JP2020151243A - wheelchair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize a wheelchair posture even during an ascending / descending motion, to ascend / descend a step in a relatively short time without giving anxiety to a wheelchair occupant, and a wheelchair occupant alone can make a step. Provide a wheelchair that can be lifted and lowered. SOLUTION: When a wheelchair 1 performs a descending motion from an upper stage 29 to a lower stage 30, the rear arm portion 11 is rotated so that its tip is directed downward, and the forearm portion 16 is rotated so that its tip is directed downward. It is rotated so that the tips of the rear arm 11 and the forearm 16 are rotated in a direction approaching each other, the front wheels 2 and the rear wheels 3 are lifted from the upper stage, and the tips of the rear arm 11 and the forearm 16 are separated from each other. When the front wheels 2 and the rear wheels 3 are brought into contact with the lower stage by rotating in the direction, the inclination of the main body 5 is kept constant by coordinating the rear arm driving unit 12 and the forearm driving unit 17. .. [Selection diagram] Fig. 1

Description

The present invention relates to a wheelchair capable of raising and lowering a step.

Conventionally, wheelchairs used when a person with walking difficulty moves include a manual wheelchair in which a passenger manually rotates wheels to travel, and an electric wheelchair in which a motor is rotated by a mounted battery. Since it is difficult for these general wheelchairs to get over a step exceeding several centimeters, there is a problem that a caregiver must accompany the wheelchair when going out, for example.

Therefore, various wheelchairs with various improvements that enable them to overcome steps have been proposed. For example, Patent Document 1 describes a plurality of undulating legs on the front of the left and right frames of a wheelchair body that can be traveled by front wheels and rear wheels, and rotatable only in one direction provided at the tips of these legs. A front leg wheel consisting of various wheels is provided, and a rear leg wheel composed of a plurality of undulating legs and wheels provided at the tips of these legs that can rotate only in one direction is provided at the rear of the left and right frames. A wheelchair step-overcoming device has been proposed in which a driving means for simultaneously undulating and driving the legs of the front limbs and the legs of the rear limbs is provided between the front limbs and the rear limbs.

Further, for example, in Patent Document 2, a device in which a plurality of telescopic cylinders with casters, a link mechanism, etc. are arranged near the left and right side surfaces of the front wheel and the rear wheel is attached, and when a step is encountered, a lever operation is performed to expand and contract the function. A wheelchair has been proposed in which the entire wheelchair can be raised while being kept horizontal by extending the lifting cylinder with casters. This wheelchair uses casters to move the wheelchair forward in the raised state, and when the front wheel of the wheelchair touches the ground on a step, the front elevating cylinder is retracted to its original state by lever operation, and the wheelchair is further moved forward to the rear wheel of the wheelchair. When the wheelchair touches the ground, the lift cylinder on the rear side is also retracted to its original state by lever operation, so the wheelchair passenger can safely get over the step without fear of falling off the wheelchair. ..

Japanese Unexamined Patent Publication No. 2001-212181 JP-A-2002-126010

However, the device of Patent Document 1 raises and lowers the wheelchair by simultaneously undulating and driving the legs of the front limbs and the legs of the rear limbs, and the driving device for undulating and driving these legs is the front limbs. Since the legs and the legs of the rear wheel are mechanically driven at the same time, and the angular speed of each leg is not controlled in a special manner, the wheelchair body tilts when the wheelchair is raised or lowered. Changes will occur, causing anxiety for wheelchair passengers and the risk of falling out of the wheelchair.

Further, the device of Patent Document 2 can be raised without changing the inclination of the entire wheelchair by extending the elevating cylinder with casters, but when overcoming a step, first, both elevating cylinders are extended. Raise the entire wheelchair, support the wheelchair with the casters of the front and rear elevating cylinders, then move it forward to place the front wheels above the upper stage, and then slightly shorten the elevating cylinder to touch the front wheels to the upper stage surface. Let me. Next, the front elevating cylinder is shortened, the wheelchair is advanced while being supported by the casters of the front wheel and the rear elevating cylinder, and the front elevating cylinder crosses the step, and the rear wheel goes up and down backward at a position beyond the step. The cylinder is shortened, the rear wheel is grounded on the upper surface, and the wheelchair is moved to the upper surface. Therefore, it is necessary to repeatedly extend and shorten the elevating cylinder, and it takes time to complete the operation of overcoming the step. Moreover, since the casters of the elevating cylinder are not provided with a driving force, it is difficult to perform a series of operations over a step without an assistant.

Therefore, according to the present invention, the posture of the wheelchair is stable even during the ascending / descending motion, and the wheelchair occupant can ascend / descend the step in a relatively short time without giving anxiety to the wheelchair occupant. It is an object of the present invention to provide a wheelchair capable of performing a step-up / down operation by itself.

In the wheelchair of the present invention, a pair of front wheels, a pair of rear wheels, a main body that movably holds the front wheels and the rear wheels, a base end is swingably supported by the main body, and the tip is the rear wheel. A rear arm portion that protrudes rearward, a rear arm drive portion that swings the rear arm portion, a rear arm ring formed at the tip of the rear arm portion, and an auxiliary drive that drives the rear arm ring in forward and reverse rotations. A forearm portion whose base end is swingably supported by the main body and whose tip protrudes forward from the front wheel, a forearm driving portion for swinging the forearm portion, and a tip of the forearm portion are formed. A forearm ring, a step detection unit for detecting that a predetermined position of the main body has passed a step, and a control unit for controlling the operation of the rear arm drive unit, the forearm drive unit, and the auxiliary drive unit. When performing the descending operation from the upper stage to the lower stage, the control unit drives the rear arm driving unit with the step facing forward, and the tip of the rear arm is directed downward. The rear arm ring contact step at the time of descending to bring the rear arm ring into contact with the upper stage, and the forearm driving unit is driven to rotate the forearm portion so that its tip points downward to rotate the front arm ring. After the step of touching down the front arm ring to touch the lower stage, the step of touching down the rear arm ring and the step of touching down the front arm ring at the time of descending are completed, the rear arm drive unit and the front arm drive unit are driven. , The rear arm portion and the tip of the forearm portion are rotated in a direction approaching each other, and the front wheel and the rear wheel are lifted from the upper stage. Is driven in a forward rotation to move forward, and based on the step passing information detected by the step detecting unit, a step passing detection step at the time of descending to determine that the rear wheel has passed the step, and a step at the time of descending When it is determined in the passage detection step that the rear wheel has passed the step, the step-down stop step for stopping the drive of the auxiliary drive unit and the step-down stop step for stopping the drive of the auxiliary drive unit are performed. A descending wheel that drives the rear arm drive unit and the fore arm drive unit to rotate the tips of the rear arm portion and the fore arm portion in a direction away from each other, and brings the front wheel and the rear wheel into contact with the lower stage. The lowering step is executed, and the control unit cooperates with the rear arm driving unit and the forearm driving unit in the descending wheel ascending step and the descending wheel lowering step. It is characterized by keeping the tilt of the main body constant.

In the wheelchair of the present invention, when performing the ascending operation from the lower stage to the upper stage, the control unit drives the rear arm driving unit with the tip of the rear arm portion in a state where the step is arranged behind. The rear bracelet grounding step at the time of ascending, in which the rear bracelet is rotated downward to bring the rear bracelet into contact with the upper stage, and the forearm driving portion are driven to rotate the forearm portion so that the tip thereof is downward, and the front After the ascending front bracelet grounding step for grounding the bracelet to the lower stage, the ascending rear bracelet grounding step, and the ascending front bracelet grounding step are completed, the rear arm driving unit and the forearm driving unit are driven. A wheel raising step at the time of ascending to lift the front wheel and the rear wheel from the lower stage by rotating the rear arm portion and the tip of the front arm portion in a direction approaching each other, and driving the auxiliary drive portion to reverse the rear bracelet. In the step-up retreat stop signal reception step and the step-up retreat stop signal reception step, which receives a signal to the effect that the drive of the rear bracelet is stopped after the front wheel has passed the step by rotationally driving and retreating. Upon receiving the signal indicating that the drive of the rear bracelet has been stopped, the rear arm drive unit and the front arm drive unit are driven to rotate the rear arm portion and the tips of the front arm portions in a direction away from each other. The control unit includes the rear arm driving unit and the forearm in the ascending wheel ascending step and the ascending wheel lowering step, comprising the ascending wheel lowering step of bringing the front wheel and the rear wheel into contact with the upper stage. It is characterized in that the inclination of the main body is kept constant by coordinating with the drive unit.

In the wheelchair of the present invention, the base end of the forearm portion is formed at the front end of the main body and is swingably supported by the footrest portion on which the occupant rests his / her foot, and the tip thereof is in front of the footrest portion. It is characterized by being protrudable.

In the wheelchair of the present invention, the control unit may perform the rear bracelet in the lowering rear bracelet grounding step, the descending front bracelet grounding step, the ascending rear bracelet grounding step, and the ascending front bracelet grounding step. It is characterized in that the ground contact of the rear bracelet is determined by detecting the disturbance torque generated when the vehicle touches the ground.

The wheelchair of the present invention further includes a first angle sensor for detecting the angle of the forearm portion with respect to the horizontal plane and a second angle sensor for detecting the angle of the rear arm portion with respect to the horizontal plane, and when performing the step-down operation. , The control unit estimates the step height based on the detection angle of the first angle sensor in a state where the front wheel and the rear wheel are in contact with each other after the step of touching down the forearm ring at the time of descending is completed. At the same time, when the step-up operation is performed, the control unit is based on the detection angle of the second angle sensor with the front wheels and the rear wheels touching the ground after the step of touching the rear brace during the step-up is completed. It is characterized by estimating the step height.

In the wheelchair of the present invention, the step detection portion is provided with the base end portion fixed to the main body and inclined downward toward the front, and the height of the tip portion thereof is the front wheel and the wheelchair. A swing bar rotatably formed around the base end portion and the swing so that the rear wheel can move from a position higher to a position lower than the height level of the ground contact surface when the rear wheel touches the ground. It has a switch that sends information indicating that when the tip of the moving bar is lower than a predetermined height to the control unit, and the control unit has a step of the step based on the information received from the switch. It is characterized by detecting the position.

According to the wheelchair of the present invention, when performing the descending operation from the upper stage to the lower stage, the rear bracelet is grounded on the upper stage, the front bracelet is grounded on the lower stage, and then the front and rear wheels are lifted from the upper stage and passed through the step. After the front wheels and the rear wheels have passed the step, the front wheels and the rear wheels are lowered until they touch the lower stage to lower the stage. Therefore, it is possible to go down the step by raising and lowering the front wheel and the rear wheel once, and it is possible to get over the step with a relatively simple operation, so that the step down operation can be performed in a short time. .. Further, the auxiliary drive unit that drives the rear bracelet in the forward and reverse rotations allows the rear bracelet that is in contact with the ground to be rotationally driven to move forward even when the front and rear wheels are lifted, so that the passenger in a wheelchair can move forward. Can be operated alone to perform a step-down operation. Then, the control unit maintains the inclination of the main body constant by coordinating the rear arm driving unit and the forearm driving unit in the wheel raising step at the time of descending and the wheel lowering step at the descending stage, so that the wheelchair during the ascending / descending operation The posture of the wheelchair is stable, and it is possible to suppress giving a feeling of anxiety to the passenger in the wheelchair.

According to the wheelchair of the present invention, when performing the ascending operation from the lower stage to the upper stage, the wheelchair is moved so that the step is behind the wheelchair, the rear bracelet is grounded on the upper stage, and the front bracelet is installed on the lower stage. The front and rear wheels are lifted from the upper stage and passed through the step, and after the front and rear wheels have passed the step, the front and rear wheels are lowered until they touch the upper stage to ascend the stage. Therefore, the step can be crossed by raising and lowering the front wheel and the rear wheel once, and the step can be raised with a relatively simple operation, so that the step-up operation can be performed in a short time. The auxiliary drive unit that drives the rear bracelet to rotate in the forward and reverse directions enables the wheelchair to retract by rotating the rear bracelet that is in contact with the ground even when the front and rear wheels are lifted. The passenger can operate the step by himself to ascend the step. Since the rear bracelet is always in contact with the ground when the wheelchair moves forward and backward while the wheelchair is moving up and down the step, it is possible to move forward and backward by providing an auxiliary drive unit for driving the rear bracelet. Then, the control unit maintains the inclination of the main body constant by coordinating the rear arm driving unit and the forearm driving unit in the ascending wheel ascending step and the ascending wheel descending step, so that the wheelchair posture during the ascending / descending operation. Is stable, and it is possible to suppress giving anxiety to the passengers in the wheelchair.

According to the wheelchair of the present invention, the base end of the forearm portion is formed at the front end of the main body and is swingably supported by the footrest portion on which the occupant rests his / her foot, and the tip of the forearm portion protrudes forward of the foot rest portion. Since it is possible, the footrest does not interfere with the step during the ascending / descending operation. In addition, since the forearm ring formed at the tip of the forearm portion is arranged so as to project forward from the foot rest portion, the forearm portion and the forearm ring do not interfere with the foot rest portion, and the swing range of the forearm portion. Since it is possible to widen the space, it is possible to cope with a relatively large step difference in height, such as a general entrance stile.

According to the wheelchair of the present invention, in the control unit, the rear bracelet or the front bracelet touches the ground in the step of descending the rear bracelet, the step of descending the front bracelet, the step of descending the rear bracelet, and the step of ascending the front bracelet. By detecting the disturbance torque generated when the bracelet is used, the contact of the rear bracelet and the front bracelet is determined. Therefore, the contact of the rear bracelet and the front bracelet can be reliably determined with a simple configuration, and the step can be overcome more safely. Can control.

According to the wheelchair of the present invention, the angle of the forearm and the angle of the rear arm are detected by a first angle sensor that detects the angle of the forearm with respect to the horizontal plane and a second angle sensor that detects the angle of the rear arm with respect to the horizontal plane. Can be detected, so that the height of the step can be calculated based on these detected angles, and the calculated height of the step can be used for control during the operation of overcoming the step.

According to the wheelchair of the present invention, when the tip of the swing bar is higher than a predetermined height, it is found that the swing bar is in contact with the ground below the swing bar, and the tip of the swing bar is in contact with the ground. When the height is lower than the predetermined height, it can be seen that the height of the ground contact surface below the swing bar is low, so that it is possible to determine whether the lower part of the swing bar is the upper step or the lower step, and swings. It can be seen that the position where the height of the bar is switched is the position of the step. Then, when the tip of the rocking bar is lower than a predetermined height, information to that effect is sent from the switch to the control unit, and the control unit detects the position of the step based on the information, so that the rocking bar is shaken. The position of the step can be accurately detected based on the physical movement of the moving bar, and the operation of overcoming the step can be safely executed.

The side view which shows the appearance structure of the wheelchair of this embodiment. The block diagram which shows the electric structure of the wheelchair of this embodiment. (A) shows a step detection unit in a state where the step detection wheel is in contact with the ground and the swing bar is raised, and (B) shows a step detection unit in a state where the step detection wheel is separated from the ground and the swing bar is lowered. Figure. FIG. 3A is a circuit diagram showing control when the step detection unit is in the state of FIG. 3A, and FIG. 3B is a circuit diagram showing control when the step detection unit is in the state of FIG. 3B. A flowchart showing the processing of the step-down operation mainly executed by the control unit. The figure which shows the first half of the wheelchair movement in order in the descending movement. The figure which shows the latter half of the wheelchair movement in order in the descending movement. A flowchart showing the processing of the step-up operation mainly executed by the control unit. The figure which shows the first half of the wheelchair movement in order in the ascending movement. The figure which shows the latter half of the wheelchair movement in order in the ascending movement. Control block diagram of the disturbance detection system. (A) is a graph showing the difference between the control signal of the disturbance detection system and the response of the estimated voltage when the front bracelet or the rear bracelet is not grounded, and (B) is the disturbance detection system when the front bracelet or the rear bracelet is grounded. The graph which shows the difference between the control signal and the response of the estimated voltage. The figure which shows the length or the angle which each value in a formula 1 to a formula 4 shows.

Hereinafter, the wheelchair 1 according to the embodiment of the present invention will be described with reference to FIGS. 1 to 13. As shown in FIGS. 1 and 2, the wheelchair 1 of the present embodiment is a wheelchair 1 including a pair of front wheels 2, a pair of rear wheels 3, and a main body 5. The front wheels 2 are casters that can rotate horizontally. The main drive unit 4 of the electric motor is connected to the rear wheel 3, and each of the pair of rear wheels 3 is formed so as to be independently rotatable in the forward and reverse directions. The wheelchair 1 moves forward by rotating both rear wheels 3 in the forward direction, and moves backward by rotating both rear wheels 3 in the reverse direction. Further, while rotating one rear wheel 3 in the forward direction, the other rear wheel 3 is stopped to rotate in the left-right direction. The main body 5 includes a frame 6 in which a metal pipe of a round cylinder is combined, a seat 7 in which a passenger in a wheelchair 1 sits, an elbow rest 8 provided on each side of the seat 7 on which the passenger puts an elbow, and boarding. It has a pair of left and right footrests 9 provided at the feet of the person, and a rear handle 10 for the caregiver to operate the wheelchair 1. The shapes of the pair of front wheels 2, the pair of rear wheels 3, and the main body 5 are not limited to this, and the present invention may have any shape as long as it is a general wheelchair 1. It can be used as a configuration of the wheelchair 1. In the present embodiment, the rear wheel 3 is an electric wheelchair 1 driven by the main drive unit 4 of the electric motor, but the wheelchair 1 of the present invention is a wheelchair 1 in which the passenger manually rotates the rear wheel 3. Good.

Further, as shown in FIGS. 1 and 2, the wheelchair 1 includes a rear arm portion 11 projecting rearward from the rear wheel 3, a rear arm driving portion 12 for swinging the rear arm portion 11, and a rear arm portion. A rear bracelet 13 formed at the tip of 11 is further provided. The base end of the rear arm portion 11 is swingably supported by the frame 6 of the main body 5. The rear arm drive unit 12 is a jack formed so as to be expandable, and one end is rotatably fixed to the frame 6 of the main body 5 and the other end is rotatably fixed to the intermediate portion in the length direction of the rear arm portion 11. The rear arm portion 11 swings due to the expansion and contraction of the rear arm driving portion 12. The rear arm driving unit 12 is not limited to a jack that can be expanded and contracted, and may be any power that can rotate the rear arm portion 11 with respect to the frame 6 about the base end thereof. The rear bracelet 13 provided at the tip of the rear arm portion 11 is connected to the auxiliary drive portion 14 of the electric motor and can rotate in the forward and reverse directions. A pair of left and right rear bracelets 13 are arranged so as to sandwich the tip of the rear arm portion 11. Further, the rear arm portion 11 is provided with a second angle sensor 15 that detects the angle formed by the length direction of the rear arm portion 11 and the horizontal plane.

Then, the wheelchair 1 further includes a forearm portion 16 whose tip protrudes forward from the front wheel 2, a forearm driving portion 17 that swings the forearm portion 16, and a forearm ring 18 formed at the tip of the forearm portion 16. Be prepared. The forearm portion 16 is supported so that its base end can swing between the pair of left and right footrest portions 9 of the main body 5 about the left-right direction of the wheelchair 1. The forearm drive unit 17 is a motor connected to the shaft at the base end of the forearm unit 16, and can rotate the forearm unit 16 in the forward and reverse directions within a predetermined range. The forearm wheel 18 is a wheel provided at the tip of the forearm portion 16 and capable of idling. A pair of left and right forearm rings 18 are provided so as to sandwich the tip of the forearm portion 16. The forearm portion 16 is provided with a first angle sensor 19 that detects the angle formed by the length direction of the forearm portion 16 and the horizontal plane. As described above, since the base end of the forearm portion 16 is swingably supported by the footrest portion 9, the tip of the forearm portion 16 can protrude forward from the footrest portion 9, and the foot is in the ascending / descending operation. Since it is possible to prevent the placing portion 9 from interfering with the step, and the forearm portion 16 and the forearm ring 18 can widen the swing range of the forearm portion 16 without interfering with the foot rest portion 9, for example, it is general. It can also handle relatively large steps with a height difference, such as a rising stile at the entrance.

Further, the wheelchair 1 is formed with a step detection unit 20 that detects that a predetermined position of the main body 5 of the wheelchair 1 has passed the step. As shown in FIGS. 1 and 3, the step detection unit 20 includes a swing bar 21 that is swingably fixed to the main body 5 and a step detection ring 22 that is slidably formed at the tip of the swing bar 21. The rocking bar 21 is formed in the vicinity of the base end of the rocking bar 21, and the rocking bar 21 has a switch 23 capable of contacting and separating. The swing bar 21 has a base end portion fixed to the main body 5 so as to be swingable, and is provided so as to be inclined downward toward the front. The step detection wheel 22 formed at the tip of the swing bar 21 can move up and down by swinging the swing bar 21, and the height thereof is when the front wheel 2 and the rear wheel 3 of the wheelchair 1 touch the ground. It is possible to move from a position higher than the height level of the ground contact surface to a position lower than the height level. When the front wheels 2 and the rear wheels 3 are in contact with the ground, the step detection wheel 22 comes into contact with the ground, so that the swing bar 21 is rotated upward. Further, when the front wheels 2 and the rear wheels 3 are lifted and separated from the ground contact surface, the step detection wheel 22 separates from the ground and the swing bar 21 rotates downward. As shown in FIG. 4, when the rocking bar 21 rotates upward, the switch 23 comes into contact with the base end of the rocking bar 21 and presses the switch 23, so that the circuit is closed and the control unit 24 is charged. Is detected. On the other hand, when the swing bar 21 rotates downward, the base end portion of the swing bar 21 separates from the switch 23, the circuit opens, and the control unit 24 does not detect the voltage.

Further, as shown in FIGS. 1 and 2, the wheelchair 1 is operated by a passenger to operate the wheelchair 1 and to start an operation of ascending / descending a step, and the wheelchair 1 A control unit 24 that controls each unit of the above is provided. The operation unit 25 operates the drive of the rear wheel 3 to operate the main operation joystick 26 provided on the elbow rest 8 and the rear bracelet 13 to operate the wheelchair 1 to move forward, backward, and turn. It has an auxiliary joystick 27 provided on the other elbow rest 8 for operating forward and backward movements during the lifting movement, and a keyboard 28 for inputting the start and stop of the lifting movement. Further, the control unit 24 is a computer connected to each unit by wire or wirelessly. The control unit 24 has a CPU, a memory, and a display (not shown), transmits commands to control each unit based on signals obtained from the operation unit 25 and each unit, and performs a process of ascending and descending a step.

Next, the processing of the step-down operation mainly performed by the control unit 24 when the wheelchair 1 configured as described above descends the step will be described with reference to FIG. When processing the step-down operation, first, the main operation joystick 26 is operated, and the step that descends from the upper step 29 to the lower step 30 in front of the wheelchair 1 in the traveling direction is the step in front of the wheelchair 1 in the traveling direction. Wheelchair 1 is arranged so that is perpendicular to the direction of travel. At this time, as shown in FIG. 6A, the forearm portion 16 and the rear arm portion 11 are arranged at lifted positions so that the tips are higher than the base ends, respectively, and the forearm ring 18 and the rear bracelet 13 are arranged. Is not grounded. Next, the passenger operates the keyboard 28 of the operation unit 25 to start the descending operation (S100).

The control unit 24 determines whether or not the step down process start operation has been performed (S100), and if it determines that the step down process start operation has been performed (S100: YES), the process proceeds to step S101. On the other hand, if it is determined that the step-down processing start operation has not been performed (S100: NO), the processing is waited as it is. Proceeding to step S101, as shown in FIG. 6B, the rear arm drive unit 12 is driven to rotate the rear arm unit 11 so that its tip points downward, and the rear bracelet 13 touches the upper stage 29. (S101).

Specifically, the control unit 24 sends a command to the rear arm drive unit 12 to drive the rear arm unit 11 in the extension direction so that the angular velocity of the rear arm unit 11 is constant, and the rear arm drive unit 12 extends. As a result, the tip of the rear arm portion 11 is gradually lowered downward. Then, as shown in a simulated manner in FIG. 11, the difference between the voltage due to the control signal u when the rear bracelet 13 touches the ground and the estimated voltage u ~ estimated from the inverse model equation of the motor based on the angular velocity is detected. Calculated as d *. Then, as shown in FIG. 12 (A), when the detected disturbance torque d * is equal to or less than a predetermined threshold value, the rear bracelet 13 is not in contact with the upper stage 29, and as shown in FIG. 12 (B), this When the detected disturbance torque d * exceeds a predetermined threshold value, it is determined that the rear bracelet 13 has touched the upper stage 29.

When the rear bracelet 13 is grounded to the upper stage 29 (S101), then, as shown in FIG. 6 (C), the forearm drive unit 17 is driven to rotate the forearm unit 16 so that its tip points downward. , The forearm ring 18 is grounded to the lower stage 30 (S102). Specifically, similarly to the rear bracelet ground contact step (S101), the control unit 24 transmits a command to the forearm drive unit 17 to drive the forearm unit 16 so that the angular velocity of the forearm unit 16 is constant. Gradually lower the tip of the. Then, as shown in FIG. 11, the difference between the voltage due to the control signal u when the forearm bracelet 18 touches the ground and the estimated voltage u ~ estimated from the inverse model equation of the motor based on the angular velocity is used as the detection disturbance torque d *. calculate. Then, as shown in FIG. 12 (A), when the detected disturbance torque d * is equal to or less than a predetermined threshold value, the forearm bracelet 18 is not in contact with the upper stage 29, and as shown in FIG. 12 (B), this When the detected disturbance torque d * exceeds a predetermined threshold value, it is determined that the front bracelet 18 has touched the lower stage 30.

When the rear bracelet 13 touches the upper stage 29 and the front bracelet 18 touches the lower stage 30, the control unit 24 then estimates the step height at the time of descending (S103). The specific step height at the time of descending is calculated based on Equation 1 described later.

As shown in FIG. 13 (A), the height h ₁ from the ground of the upper stage 29 to the axis of the base end of the forearm portion 16, the radius r _{1 of} the forearm bracelet 18, and the length of the forearm portion 16 (the base of the forearm portion 16). The length from the end axis to the central axis of the forearm ring 18) L ₁ is a fixed numerical value, so that the control unit 24 stores these numerical values in advance, and the forearm portion 16 is in the length direction with respect to the horizontal plane. The first angle sensor 19 detects the angle θ ₁ . Then, the control unit 24 substitutes these numerical values h1, r1, L1, and θ1 into the following mathematical formula 1 to calculate the step height H. In this embodiment, the "characters of θ ₁ and H with a circumflex (^)" included in the formulas 1 to 4 are "θ ₁ " and "H" with the circumflex (^) omitted. Represents.

After completing the process of estimating the step height (A103), the rear arm driving unit 12 and the forearm driving unit 17 are then driven so that the tips of the rear arm portion 11 and the forearm portion 16 approach each other. The arm portion 11 and the forearm portion 16 are rotated, and as shown in FIG. 6D, the lowering wheel raising step of lifting the front wheel 2 and the rear wheel 3 from the upper step 29 is executed (S104). In this step of raising the wheels at the time of descending, the inclination of the main body 5 of the wheelchair 1 is maintained constant by coordinating the rear arm driving unit 12 and the forearm driving unit 17. That is, when the rear arm driving unit 12 and the forearm driving unit 17 are driven to lift the main body 5 of the wheelchair 1, the angular velocities of the rear arm driving unit 12 and the forearm driving unit 17 are adjusted, and the base end of the rear arm driving unit 12 is adjusted. By controlling the base ends of the forearm drive unit 17 to be lifted in the vertical direction at the same speed, the front wheels 2 and the rear wheels 3 of the wheelchair 1 are horizontally the same as the posture of the main body 5 when they are in contact with the ground. It lifts up as it is in the posture.

Specifically, the step of raising the wheel at the time of descending is the amount of change Δθ of the angle of the forearm 16 when lifting the main body 5 of the wheelchair 1 while maintaining the posture of the wheelchair 1 based on the mathematical formulas 2 and 3 described later. _The amount of change Δθ ₂ in the angles of ₁ and the hind arm 11 is calculated. The step height H is calculated in the above-mentioned estimation of the step height at the time of descending (S103), and is the height h ₁ from the ground of the upper step 29 to the axis of the base end of the forearm portion 16 and the radius of the forearm ring 18. r ₁ , the length of the forearm portion 16 (the length from the axis of the base end of the forearm portion 16 to the central axis of the forearm ring 18) L ₁ is a fixed numerical value. Then, the height h ₂ from the ground of the upper stage 29 to the axis of the base end of the rear arm portion 11, the radius r ₂ of the rear bracelet 13, and the length of the forearm portion 16 (from the axis of the base end of the forearm portion 16 to the forearm ring 18). The length to the central axis of) L ₂ is also a fixed value. Further, the angle θ ₁ in the length direction of the forearm 16 with respect to the horizontal plane is detected by the first angle sensor 19, and the angle θ ₂ in the length direction of the rear arm 11 with respect to the horizontal plane is detected by the second angle sensor 15. .. Therefore, the control unit 24 inputs the amount of change ΔH for lifting the main body 5 into the formulas 2 and 3, so that the angle of the forearm portion 16 required to lift the main body 5 upward without changing its posture. The amount of change Δθ ₁ and the amount of change Δθ ₂ in the angle of the hind arm 11 can be calculated.

As described above, the drive of the forearm drive unit 17 is controlled based on the calculated change amount Δθ ₁ of the angle of the forearm portion 16, and the forearm drive unit is based on the change amount Δθ ₂ of the angle of the rear arm portion 11. The drive of the wheelchair 1 is controlled, and the main body 5 of the wheelchair 1 is lifted to the height of ΔH while maintaining the posture of the main body 5 of the wheelchair 1.

Next, when the passenger of the wheelchair 1 operates the auxiliary joystick 27 of the operation unit 25 (S105: YES), the auxiliary drive unit 14 is driven and the rear bracelet 13 is driven in the forward rotation direction. , Advance wheelchair 1. On the other hand, if the auxiliary joystick 27 of the operation unit 25 is not operated, the process waits (S105: NO). The wheelchair 1 of the present invention is not limited to the one in which the auxiliary drive unit 14 is driven by the operation of the passenger, and even if the wheelchair 1 is automatically driven by the auxiliary drive unit 14 when the wheel raising step at the time of descending is completed. Good.

Then, when the wheelchair 1 moves forward and the predetermined position of the main body 5 passes the step, the step detection unit 20 detects that the step has been passed (S106). Specifically, when the step detection wheel 22 of the step detection unit 20 is separated from the upper stage 29, the swing bar 21 rotates downward to press the switch 23, the circuit is closed, and the control unit 24 detects the voltage. Since the step detection unit 20 has a configuration in which the switch 23 is pressed by the physical movement of the swing bar 21 in this way, the certainty of the step detection can be improved. After the step detection unit 20 detects the step, the control unit 24 further drives the auxiliary drive unit 14 to advance the wheelchair 1 until the rear wheel 3 passes over the step, as shown in FIG. 7A. And stop (S107). Specifically, the control unit 24 stores in advance a predetermined distance between the position where the step detection unit 20 in the main body 5 detects the step and the position of the rear wheel 3, and the step detection unit 20 detects the step. Then, when the wheelchair 1 advances a predetermined distance, the auxiliary drive unit 14 is stopped.

When the wheelchair 1 is stopped, then, as shown in FIG. 7B, the rear arm driving unit 12 and the forearm driving unit 17 are driven, and the tips of the rear arm portion 11 and the forearm portion 16 are separated from each other. The rear arm portion 11 and the forearm portion 16 are rotated, and the front wheel 2 and the rear wheel 3 are gradually lowered to bring the front wheel 2 and the rear wheel 3 into contact with the lower stage 30 (S108). In this step of lowering the wheels at the time of descending, the inclination of the main body 5 of the wheelchair 1 is maintained constant by coordinating the rear arm driving unit 12 and the forearm driving unit 17. That is, when the rear arm driving unit 12 and the forearm driving unit 17 are driven to lower the main body 5 of the wheelchair 1, the angular velocities of the rear arm driving unit 12 and the forearm driving unit 17 are adjusted, and the base end of the rear arm driving unit 12 is adjusted. By controlling the base ends of the forearm drive unit 17 to descend in the vertical direction at the same speed, the front wheels 2 and the rear wheels 3 of the wheelchair 1 are horizontally the same as the posture of the main body 5 when they are in contact with the ground. It goes down as it is in the posture. Specifically, the wheel lowering step at the time of descending is based on the above-mentioned formulas 2 and 3, and the amount of change in the angle of the forearm portion 16 when lowering the main body 5 of the wheelchair 1 while maintaining the posture of the wheelchair 1 Δθ1. And the amount of change Δθ2 in the angle of the hind arm portion 11 is calculated. Since the specific description of the formula 2 and the formula 3 is as described above, the description thereof will be omitted. Therefore, the control unit 24 changes the angle of the forearm 16 required to lift the main body 5 without changing its posture by inputting the change amount ΔH for lowering the main body 5 into the formulas 2 and 3. It is possible to calculate the amount Δθ1 and the amount of change Δθ2 in the angle of the hind arm portion 11. Then, the drive of the forearm drive unit 17 is controlled based on the calculated change amount Δθ1 of the angle of the forearm portion 16, and the drive of the forearm drive unit 17 is controlled based on the change amount Δθ2 of the angle of the rear arm portion 11. While maintaining the posture of the main body 5 of the wheelchair 1, the main body 5 of the wheelchair 1 is lowered to bring the front wheels 2 and the rear wheels 3 into contact with the ground.

When the wheel lowering step at the time of descending is completed, as shown in FIG. 7C, the forearm driving unit 17 and the rear arm driving unit 12 are driven, and the tips of the forearm portion 16 and the rear arm portion 11 are lifted and descended. Complete the step processing.

Next, the step-up process mainly performed by the control unit 24 when the wheelchair 1 ascends the step will be described with reference to FIG. When performing the step-up process, first, the main operation joystick 26 is operated so that the step rising from the lower step 30 to the upper step 29 rearward in the traveling direction of the wheelchair 1 is perpendicular to the backward direction of the wheelchair 1. Wheelchair 1 is placed. At this time, as shown in FIG. 9A, the forearm portion 16 and the rear arm portion 11 are arranged at lifted positions so that the tips are higher than the base ends, respectively, and the forearm ring 18 and the rear bracelet 13 are arranged. Is not grounded. Next, the passenger operates the keyboard 28 of the operation unit 25 to start the ascending process.

When the control unit 24 determines whether or not the start operation of the step-up process has been performed (S200) and determines that the start operation of the step-up process has been performed (S200: YES), the process proceeds to step S201. On the other hand, if it is determined that the start operation of the step-up process has not been performed (S200: NO), the process is waited as it is. Proceeding to step S201, as shown in FIG. 9B, the rear arm drive unit 12 is driven to rotate the rear arm unit 11 so that its tip points downward, and the rear bracelet 13 touches the upper stage 29. (S201).

Specifically, the control unit 24 sends a command to the rear arm drive unit 12 to drive the rear arm unit 11 in the extension direction so that the angular velocity of the rear arm unit 11 is constant, and the rear arm drive unit 12 extends. As a result, the tip of the rear arm portion 11 is gradually lowered downward. Then, as shown in FIG. 11, the difference between the voltage due to the control signal u when the rear bracelet 13 touches the ground and the estimated voltage u ~ estimated from the inverse model equation of the motor based on the angular velocity is used as the detection disturbance torque d *. calculate. Then, as shown in FIG. 12 (A), when the detected disturbance torque d * is equal to or less than a predetermined threshold value, the rear bracelet 13 is not in contact with the upper stage 29, and as shown in FIG. 12 (B), this When the detected disturbance torque d * exceeds a predetermined threshold value, it is determined that the rear bracelet 13 has touched the upper stage 29.

When the rear bracelet 13 is grounded to the upper stage 29 (S201), then, as shown in FIG. 9 (C), the forearm drive unit 17 is driven to rotate the forearm unit 16 so that its tip points downward. , The forearm ring 18 is grounded to the lower stage 30 (S202). Specifically, similarly to the rear bracelet ground contact step (S201), the control unit 24 transmits a command to the forearm drive unit 17 to drive the forearm unit 16 so that the angular velocity of the forearm unit 16 is constant. Gradually lower the tip of the. Then, as shown in FIG. 11, the difference between the voltage due to the control signal u when the forearm bracelet 18 touches the ground and the estimated voltage u ~ estimated from the inverse model equation of the motor based on the angular velocity is used as the detection disturbance torque d *. calculate. Then, as shown in FIG. 12 (A), when the detected disturbance torque d * is equal to or less than a predetermined threshold value, the forearm bracelet 18 is not in contact with the upper stage 29, and as shown in FIG. 12 (B), this When the detected disturbance torque d * exceeds a predetermined threshold value, it is determined that the rear bracelet 13 has touched the lower stage 30.

When the rear bracelet 13 touches the upper stage 29 and the front bracelet 18 touches the lower stage 30, the control unit 24 then estimates the step height at the time of ascending (S203). The specific step height at the time of ascending is calculated based on the formula 4 described later.

As shown in FIG. 13 (B), the height h ₂ from the ground of the lower stage 30 to the axis of the base end of the rear arm portion 11, the radius r ₂ of the rear bracelet 13, and the length of the rear arm portion 11 (rear arm portion). Since the length L ₂ from the axis at the base end of 11 to the central axis of the rear bracelet 13 is a fixed numerical value, the control unit 24 stores these numerical values in advance, and the rear arm portion 11 with respect to the horizontal plane The second angle sensor 15 is made to detect the angle θ ₂ in the length direction. Then, the control unit 24 substitutes these numerical values h ₂ , r ₂ , L ₂ , and θ ₂ into the following equation 1 to calculate the step height H. In this embodiment, the "characters of θ ₂ and H with a circumflex (^)" included in the formulas 1 to 4 are "θ ₂ " and "H" with the circumflex (^) omitted. Represents.

After completing the process of estimating the step height (S203), the rear arm driving unit 12 and the forearm driving unit 17 are then driven so that the tips of the rear arm portion 11 and the forearm portion 16 approach each other. The arm portion 11 and the forearm portion 16 are rotated, and as shown in FIG. 9D, the wheel ascending step of lifting the front wheel 2 and the rear wheel 3 from the upper stage 29 is executed (S204). In this step of ascending the wheel, the inclination of the main body 5 of the wheelchair 1 is maintained constant by coordinating the rear arm driving unit 12 and the forearm driving unit 17. That is, when the rear arm driving unit 12 and the forearm driving unit 17 are driven to lift the main body 5 of the wheelchair 1, the angular velocities of the rear arm driving unit 12 and the forearm driving unit 17 are adjusted, and the base end of the rear arm driving unit 12 is adjusted. By controlling the base ends of the forearm drive unit 17 to be lifted in the vertical direction at the same speed, the main body 5 has the same posture as when the front wheels 2 and the rear wheels 3 of the wheelchair 1 are horizontally in contact with the ground. Is lifted upward as it is.

Specifically, the step of raising the wheel during ascending is the amount of change in the angle of the forearm 16 when lifting the main body 5 of the wheelchair 1 while maintaining the posture of the wheelchair 1 based on the above-mentioned equations 2 and 3. Δθ ₁ And the change amount Δθ ₂ of the angle of the forearm portion 11 is calculated, and the drive of the forearm drive portion 17 is controlled based on the calculated change amount Δθ ₁ of the angle of the forearm portion 16, and the change of the angle of the forearm portion 11 is performed. Based on the amount Δθ ₂ , the drive of the forearm driving unit 17 is controlled, and the main body 5 of the wheelchair 1 is lifted to the height of ΔH while maintaining the posture of the main body 5 of the wheelchair 1.

Next, when the passenger of the wheelchair 1 operates the auxiliary joystick 27 of the operation unit 25 (S205: YES), the auxiliary drive unit 14 is driven and the rear bracelet 13 is driven in the reverse rotation direction. , Retract wheelchair 1. On the other hand, if the auxiliary joystick 27 of the operation unit 25 is not operated, the process waits (S205: NO). The wheelchair 1 of the present invention is not limited to the one in which the auxiliary drive unit 14 is driven by the operation of the passenger, and the auxiliary drive unit 14 may be automatically driven when the wheel ascending step at the time of ascending is completed. ..

Then, the wheelchair 1 is retracted, and as shown in FIG. 10A, the wheelchair 1 is retracted until the front wheel 2 passes over the step, and the passenger operates the auxiliary joystick 27 to stop the retreat. Then, the auxiliary drive unit 14 is stopped to stop the wheelchair 1 from retreating (S206: YES). The control unit 24 may automatically stop the auxiliary drive unit 14 after the front wheel 2 has passed over the step based on the step position detected by the step detection unit 20 in the main body 5.

When the wheelchair 1 is stopped, the control unit 3 performs a step of receiving a reverse stop signal at the time of ascending stage to receive a signal from the auxiliary drive unit 14 to the effect that the drive of the rear bracelet 13 has been stopped (S207), and then FIG. 10 (B). ), The rear arm drive unit 12 and the forearm drive unit 17 are driven to rotate the rear arm portion 11 and the forearm portion 16 in the direction in which the tips of the rear arm portion 11 and the forearm portion 16 are separated from each other. The wheel lowering step at the time of ascending is executed by gradually lowering the 2 and the rear wheel 3 to bring them into contact with the upper 29 (S208). In this step of lowering the wheels at the time of ascending, the inclination of the main body 5 of the wheelchair 1 is maintained constant by coordinating the rear arm driving unit 12 and the forearm driving unit 17. That is, when the rear arm driving unit 12 and the forearm driving unit 17 are driven to lower the main body 5 of the wheelchair 1, the angular velocities of the rear arm driving unit 12 and the forearm driving unit 17 are adjusted, and the base end of the rear arm driving unit 12 is adjusted. By controlling the base ends of the forearm drive unit 17 to descend in the vertical direction at the same speed, the front wheels 2 and the rear wheels 3 of the wheelchair 1 are horizontally the same as the posture of the main body 5 when they are in contact with the ground. It goes down as it is in the posture. Specifically, the wheel lowering step at the time of ascending is based on the above-mentioned formulas 2 and 3, and the amount of change Δθ1 and the amount of change in the angle of the forearm 16 when lowering the main body 5 of the wheelchair 1 while maintaining the posture of the wheelchair 1. The amount of change Δθ2 in the angle of the hind arm portion 11 is calculated. Since the specific description of the formula 2 and the formula 3 is as described above, the description thereof will be omitted. Therefore, the control unit 24 changes the angle of the forearm 16 required to lift the main body 5 without changing its posture by inputting the change amount ΔH for lowering the main body 5 into the formulas 2 and 3. It is possible to calculate the amount Δθ1 and the amount of change Δθ2 in the angle of the hind arm portion 11. Then, the drive of the forearm drive unit 17 is controlled based on the calculated change amount Δθ1 of the angle of the forearm portion 16, and the drive of the forearm drive unit 17 is controlled based on the change amount Δθ2 of the angle of the rear arm portion 11. The main body 5 of the wheelchair 1 is lowered while maintaining the posture of the main body 5 of the wheelchair 1, and the front wheels 2 and the rear wheels 3 are brought into contact with the ground.

When the wheel lowering step at the time of ascending is completed, as shown in FIG. 10C, the forearm driving unit 17 and the hind arm driving unit 12 are driven, and the tip of the forearm portion 16 and the hind arm portion 11 is lifted to descend the stage. Complete the process.

As described above, the wheelchair 1 of the present embodiment can raise and lower the step by raising and lowering the front wheels 2 and the rear wheels 3 once, and can easily move up and down in a relatively short time. it can. Then, the auxiliary drive unit 14 that drives the rear bracelet 13 in the forward and reverse rotations can rotate the rear bracelet 13 that is in contact with the ground to move forward and backward even when the front wheels 2 and the rear wheels 3 are lifted. Therefore, the passenger in the wheelchair 1 can operate the wheelchair 1 by himself to raise and lower the step. Then, since the control unit 24 maintains the inclination of the main body 5 constant by coordinating the rear arm drive unit 12 and the forearm drive unit 17, the posture of the wheelchair 1 during the ascending / descending operation is stabilized, and the wheelchair 1 is boarded. It is possible to suppress giving anxiety to a person.

It goes without saying that the embodiment of the present invention is not limited to the above-described embodiment and can be appropriately changed without departing from the scope of the idea of the present invention.

The wheelchair 1 according to the present invention is suitable as a wheelchair 1 capable of ascending and descending steps without the need for an assistant.

1 Wheelchair 2 Front wheel 3 Rear wheel 4 Main drive wheel 5 Main body 11 Rear arm part 12 Rear arm drive part 13 Rear bracelet 14 Auxiliary drive part 15 Second angle sensor 16 Forearm part 17 Forearm drive part 18 Forearm wheel 19 First angle sensor 20 Step detection unit 21 Swing bar 23 Switch 24 Control unit 25 Operation unit 29 Upper stage 30 Lower stage

Claims (6)

A pair of front wheels and
A pair of rear wheels and
A main body that holds the front wheels and the rear wheels so that they can run,
A rear arm portion whose base end is swingably supported by the main body and whose tip protrudes rearward from the rear wheel.
The rear arm drive unit that swings the rear arm unit and
The hind bracelet formed at the tip of the hind arm and
An auxiliary drive unit that drives the rear bracelet in the forward and reverse rotations,
A forearm portion whose base end is swingably supported by the main body and whose tip protrudes forward from the front wheel.
The forearm drive unit that swings the forearm unit and
The forearm bracelet formed at the tip of the forearm and
A step detection unit that detects that a predetermined position of the main body has passed a step,
The rear arm drive unit, the forearm drive unit, and a control unit that controls the operation of the auxiliary drive unit are provided.
When performing the descending operation from the upper stage to the lower stage, the control unit is in a state where the step is arranged in front.
A rear bracelet grounding step at the time of descending, in which the rear arm driving unit is driven to rotate the rear arm portion so that its tip points downward, and the rear bracelet is grounded to the upper stage.
A forearm bracelet grounding step at the time of descending, in which the forearm driving portion is driven to rotate the forearm portion so that its tip points downward, and the forearm bracelet is grounded to the lower stage.
After the step of touching down the rear bracelet and the step of touching down the front bracelet during descending are completed, the rear arm driving unit and the forearm driving unit are driven so that the tips of the rear arm and the forearm approach each other. A wheel raising step at the time of descending, in which the front wheel and the rear wheel are lifted from the upper stage by rotating in the direction of
At the time of descending, it is determined that the rear bracelet has passed the step based on the step passage information detected by the step detection unit by driving the auxiliary drive unit to drive the rear bracelet in the forward rotation to move forward. Step passage detection step and
When it is determined that the rear wheel has passed the step in the step-down step passage detection step, the step-down stop step for stopping the driving of the auxiliary drive unit and the step-down stop step.
When the drive of the auxiliary drive unit is stopped in the step of stopping at the time of descending, the rear arm drive unit and the forearm drive unit are driven to rotate in a direction in which the tips of the rear arm portion and the forearm portion are separated from each other. , The wheel lowering step at the time of descending to bring the front wheel and the rear wheel into contact with the lower stage,
Is to execute
The control unit is characterized in that the inclination of the main body is kept constant by coordinating the rear arm driving unit and the forearm driving unit in the descending wheel raising step and the descending wheel lowering step. Wheelchair. When performing the ascending operation from the lower stage to the upper stage, the control unit is in a state where the step is arranged behind.
A rear bracelet grounding step at the time of ascending, in which the rear arm driving unit is driven to rotate the rear arm portion so that its tip points downward, and the rear bracelet is grounded to the upper stage.
A forearm bracelet grounding step at the time of ascending, in which the forearm driving unit is driven to rotate the forearm portion so that its tip points downward, and the forearm bracelet is grounded to the lower stage.
After the rear bracelet grounding step at the time of ascending and the forearm grounding step at the time of ascending are completed, the rear arm driving unit and the forearm driving unit are driven so that the tips of the rear arm portion and the forearm portion approach each other. And the wheel raising step at the time of ascending to lift the front wheel and the rear wheel from the lower stage.
A backward stop signal at the time of ascending to receive a signal to the effect that the auxiliary drive unit is driven to reversely drive the rear bracelet to retract the rear bracelet, and after the front wheel has passed the step, the drive of the rear bracelet is stopped. Receive step and
When the signal indicating that the driving of the rear bracelet is stopped is received in the step of receiving the backward stop signal at the time of ascending stage, the rear arm driving unit and the forearm driving unit are driven to drive the rear arm portion and the tip of the forearm portion. And the wheel lowering step at the time of ascending, in which the front wheels and the rear wheels are brought into contact with the upper stage by rotating the wheels in a direction away from each other.
With
The control unit is characterized in that the inclination of the main body is kept constant by coordinating the rear arm driving unit and the forearm driving unit in the ascending wheel raising step and the ascending wheel lowering step. The wheelchair according to claim 1. The base end of the forearm portion is formed on the front end of the main body and is swingably supported by the footrest portion on which the user places his / her foot, and the tip can project forward from the footrest portion. The wheelchair according to claim 2. The control unit occurs when the rear bracelet touches the ground in the lower stage rear bracelet ground contact step, the lower stage front bracelet ground contact step, the ascending rear bracelet ground contact step, and the ascending front bracelet ground contact step. The wheelchair according to claim 2 or 3, wherein the ground contact of the rear bracelet is determined by detecting the disturbance torque. A first angle sensor that detects the angle of the forearm with respect to the horizontal plane,
A second angle sensor that detects the angle of the hind arm with respect to the horizontal plane,
With more
When performing the step-down operation, the control unit is based on the detection angle of the first angle sensor in a state where the front wheel and the rear wheel are in contact with the ground after the step of step-down front bracelet ground contact is completed. Estimate the step height and
When performing the step-up operation, the control unit steps after the rear bracelet grounding step at the time of step-up is completed, with the front wheels and the rear wheels touching the ground, based on the detection angle of the second angle sensor. The wheelchair according to any one of claims 2 to 4, wherein the height is estimated. The step detection unit
The base end portion is fixed to the main body and is provided so as to be inclined downward toward the front, and the height of the tip end portion of the ground contact surface when the front wheel and the rear wheel touch the ground. A swing bar rotatably formed around the base end so that it can move from a position higher than the height level to a position lower than the height level.
A switch that sends information indicating that when the tip of the swing bar is lower than a predetermined height to the control unit.
Have and
The wheelchair according to any one of claims 1 to 5, wherein the control unit detects the position of the step based on the information received from the switch.

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