JPH01244748A - Floating leg phase control thigh artificial leg - Google Patents

Abstract

PURPOSE:To properly execute the control of the pursuit of a floating leg phase corresponding to respective speeds by providing a sensor to detect the change of a relative angle between a thigh frame part and a lower thigh frame part, deriving a floating leg phase time from the time of a standing leg phase obtained from the detecting signal, and controlling the valve operation of an air cylinder in the floating leg phase time. CONSTITUTION:Between both side upper edges of a lower thigh frame part 2 and the shaft front extended part of a thigh frame part 1, stoppers 7 for preventing an excessive extension made of a rubber material are provided at both sides, an interval between both stoppers is utilized as the vicinity position of a knee shaft 3, a knee angle sensor 8 is fitted at the front upper part internal side of the lower thigh frame part, and a neighboring piece 9 is fitted in the shaft front extended part of the thigh frame part 1. The sensor 8 and neighboring piece 9 detect the change of an angle prepared by both frame parts around the knee shaft 3 by approaching and separating, the standing leg phase and floating leg phase are decided by a microcomputer by means of the detecting signal, a rotary solenoid 6 is operated by the control signal, valves of an air cylinder 5 are multistage-controlled, and the movement of the lower thigh frame part in the floating leg phase is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a femoral prosthesis for a transfemoral amputee having residual muscle around the stump.

(Prior Art) FIG. 6 shows sequential changes in the posture of the right side of the body when a healthy person is walking. (a) shows the heel, (a) shows the knee, (C) shows the crotch, (d) shows the lower leg, and (e) shows the thigh. It is subjected to a ground reaction force (f) in a substantially vertical direction as shown.

The period from leaving the bed to the next landing is the swing phase.

FIG. 7 shows an example of a general femoral prosthesis using an air cylinder (g) (see Japanese Patent Publication No. 47638/1983).

The thigh frame part (b) and the lower leg frame part (i) are connected to the knee axis (
j), and an air cylinder (g) is interposed between the two parts. During the stance phase, both parts come into contact with the stopper (stopper) to prevent knee bending, and during the swing phase, the lower leg frame section (i) below the knee axis (j) acts as a kind of pendulum, but the air cylinder (6) It compensates for the action of the lower leg control muscles by using the braking force due to the flow resistance and the repulsive force due to air compression.

In the above-mentioned case, the internal structure of the air cylinder (g) is adjusted so that the suspension, swinging, and cushioning of the lower leg frame are appropriate at a constant walking speed.

Figures 8(a) and 8(b) show another example of the prior art femoral prosthesis. The body weight switch built into the lower leg frame (i) is equipped with a metal plate electrode (ml) as shown in Figure 8 (c).
) (m2) with a pressurized conductive rubber (n) sandwiched between them and a certain load is applied, it turns on, and as shown in the control circuit block diagram in Figure 8 (d), this ON signal causes the microcomputer (0 ) operates and controls the air cylinder (barrel pulp (r)) via the rotary solenoid (q). (S) is the battery that powers it.

(Problems to be Solved by the Invention) The prior art femoral prosthesis shown in FIG. It is possible to control according to each walking speed such as when crossing an intersection, and the control characteristics can be brought close to the model, and functionally the mobility of the prosthesis is relatively good. However, the structure of this femoral prosthesis requires improvement in the following points.

(i) A large space is required for the weight switch;
The overall length tends to be longer. This makes it difficult to apply it to children and women.

(ii) There is a high possibility that the weight switch will malfunction due to changes in ground reaction force due to ground conditions or due to deterioration of the sliding part of the shaft. This may cause problems in terms of safety.

(ij) Since the weight switch is a contact type sensor, the sliding part is subject to friction and its lifespan is short.

(iv) 1N arrangement, maintenance is generally troublesome;

(v) Since the weight switch wiring is exposed to the outside, it is easily disconnected.

(vi) Displacement between the actuating parts required for ON-OFF of the weight switch causes malfunction. It also causes poor walking feeling.

(vi) Since the weight switch is provided at the bottom of the lower leg frame, the center of gravity including the attachment is located at a lower position, making the wearer feel heavier than the actual weight.

(Means for Solving the Problems) The present invention has been made to solve the above-mentioned problems of the prior art femoral prosthesis shown in FIG. This eliminates the need to rely on a body weight switch that is turned on when the thigh frame is moved, and an angular displacement detection sensor that detects the angle between the thigh frame and the lower leg frame is installed at the knee axis. The stance phase and swing phase are distinguished by extension and flexion. The ground reaction force due to the body weight is supported by the knee axis and is not applied to the angular displacement detection sensor. Therefore, as angular displacement detection sensors that operate without load, it is now possible to use highly sensitive sensors such as proximity switches and photoelectric switches that operate non-contact with minute angular displacements, and contact limit switches and potentiometers that operate without contact can also be used. May be operated under similar operating conditions.

That is, the swing phase control femoral prosthesis of the present invention has an overall structure in which a thigh frame for attachment and a lower leg frame are pivotally connected by the knee axis, and an air cylinder is interposed between the two parts. In the prosthetic leg, a sensor is installed near the knee axis to detect changes in the relative angle between the two parts, and the swing phase duration at each walking speed is derived from the stance phase time obtained from the detection signal. The present invention is characterized in that a microcomputer control device is provided to control valve operation of the air cylinder.

(Function) According to the present invention, changes in the bending and stretching of both frame parts around the knee axis occur regularly as one walks, regardless of the way the weight is applied to the prosthesis, which tends to vary between individuals wearing the thigh prosthesis. Depending on the situation, stance phase time can be detected relatively accurately, and from this, for example, the corresponding swing phase duration and swing/stance time ratio can be determined from actual gait data at three stages of low, medium, and high, and these factors and gait can be determined. The relationship between changes in walking conditions at each speed can be more closely investigated and used to improve controllability.

Moreover, the sensor for detecting the bending/extending angle at the knee in the present invention is
Structurally, unlike the conventional weight switch, which is installed between the two halves of the lower leg frame member and must be displaced under the largest load of body weight, the load is received by the knee axis and does not directly act on the sensor. Therefore, a compact and highly sensitive device can be adopted, and as a result, the relative arrangement of each component can be rationalized and simplified.

(Example) Hereinafter, the control femoral prosthesis for swinging legs of the present invention will be described below.
A detailed explanation will be given based on an example with reference to the drawings. FIG. 1 is a longitudinal sectional side view of the essential parts of the present invention in the first embodiment, and FIG. 2 is a front view thereof. For related parts equivalent to the prior art that are not shown, please refer to the illustrations and explanations as necessary. It shall be.

In Figures 1 and 2, the portion of the thigh frame (1) and the portion of the lower leg frame (2), which are shown as mounting plates for the socket that fit onto the wearer, are pivotally connected at the knee axis (3). Ru. In this example, the knee axis (3) is the lower leg frame (
2), and the thigh frame (1) is fixed to the side of the bush (
4) is rotatably held around the knee axis (3).

The axial rear extension of the thigh frame section (1) is connected to the lower leg frame section (2) by an air cylinder (5) which includes a flow control means for pulp or the like similar to that in the prior art. A rotary solenoid (6) is provided to control valve operation.

The upper ends of both sides of the lower leg frame part (2) and the thigh frame part (1
) are provided with stoppers (7) made of rubber on both sides to prevent overextension. and knee axis (3)
A knee angle sensor (8) consisting of a proximity switch is installed on the inside of the front upper part of the lower leg frame, using the distance between the two stoppers as a position close to The extension has a proximal piece made of metal plate (
9) Install.

The sensor (8) and the proximal piece (9) detect changes in the angle formed by both frame parts around the knee axis (3) by approaching and separating, and the detection signal is used to determine the stance phase and the stance phase in a microcomputer as in the prior art. It is determined whether the leg is for free leg use, and the rotary solenoid (6) is operated based on the control signal to control the valves of the air cylinder (5) in multiple stages to control the movement of the lower leg frame portion during the free leg use.

In the above embodiment, the sensor (8) may be of any type as long as it detects when the knee axis angle falls within a certain range of angles before and after the extended state, and therefore it does not matter what type it is or where it is installed near the knee axis. For example, not only the above-mentioned proximity switch,
It can also be used with non-contact photoelectric switches, contact limit switches, etc. Further, the control device is not limited to the illustrated microcomputer, but may be a combination of IC chips such as an I10 chip and a comparator having equivalent functions.

FIG. 3 shows a flowchart of the control operation of this type of embodiment. The control operations are performed in the order and manner shown in the figure.

FIG. 4 shows a longitudinal sectional view of a modified part of a slightly modified embodiment, and equivalent parts are designated by the same reference numerals.

In this embodiment, instead of the proximity sensor of the previous embodiment, a potentiometer 00) is provided on the knee shaft (3), and together with the contactor (11) attached to the thigh frame (1), the knee shaft angle can be adjusted. Detection of Since the potentiometer can continuously detect changes in angle, it is also possible to continuously change the opening degree of the pulp of the air cylinder.

However, for the purpose of the present invention, it is only necessary to accurately detect the stance phase time when the knee axis angle is within a certain range, so the operation is performed according to the flowchart shown in FIG. 5(a) and the time shown in FIG. 5(b). As shown in the diagram of the detected value signal of the angular coordinate, comparison is made at a constant darkness value (TH), and the time t during which the signal is below the darkness value is measured and taken as the stance phase time.

(Effects of the Invention) According to the present invention, even if the walking speed changes from low speed to medium speed to high speed, the following function for the swing leg can be appropriately controlled in accordance with each speed. This has the effect of providing a femoral prosthesis.

In addition, since there is no body weight switch that must be activated under heavy loads, it is possible to save space, reduce weight, and create a compact model for women's use. , it is unaffected by ground conditions, has no sliding resistance parts, has a long service life and is reliable over a long period of time, is easy to adjust and maintain, prevents malfunctions, does not have to worry about disconnection, and the sensor is commercially available. Since a plate can be used, various effects such as being able to be manufactured at low cost can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional side view of the main parts of a swing phase control femoral prosthesis according to one embodiment of the present invention, Fig. 2 is a front view thereof, Fig. 3 is a flowchart of its control operation, and Fig. 4 is the invention of the present invention. FIG. 5(a) is a flowchart of the control operation, and FIG. 5(b) is a longitudinal sectional view of the changed part of the modified example.
A diagram of signal detection on angular coordinates, Figure 6 is a diagram showing sequential changes in the walking situation of a healthy person, Figure 7 is a side view of an example of a conventional femoral prosthesis, and Figure 8 (A) is a diagram of signal detection on angular coordinates. A side view of the other side of the femoral prosthesis of the prior art, FIG. 8(B) is a front view thereof, FIG.
C) is a schematic explanatory diagram of the weight switch, and FIG. 8(D) is a block diagram of its control circuit. (1)...Thigh frame part, (2)...Lower leg frame part, (3)...Plb, (4)...Buttons, (
5)...Air cylinder, (6)...Rotary solenoid, (7)...Stopper, (8)...Sensor, (9)...Proximity piece, 00)...Potentiometer, ( 11)...Contact, (TI()...Darkness value, (1
)...time, (a)...heel, (b)...knee,
(C)...Thigh, (d)...Lower leg, (e)...Thigh, bulge)...Ground reaction force, (→...Air cylinder,
(5)... Thigh frame part, (i)... Lower leg frame part, (j)... Knee axis, (k)... Stopper, (
f)... Weight switch, (ml) (m2)... Metal plate electrode, (n)... Pressurized conductive rubber, (0)...
Microcomputer, (P)...driver, (q)
...Rotary solenoid, (r)...Valve, (S
)···battery.

Claims (1)

[Claims] In a femoral prosthesis in which the thigh frame for attachment and the lower leg frame are pivotally connected at the knee axis and an air cylinder is interposed between the two parts, a sensor is installed near the knee axis to detect changes in the relative angle between the two parts. and a microcomputer control device that derives the swing phase time at each walking speed from the stance phase time obtained from the detection signal and controls the valve operation of the air cylinder during the swing phase time. Femoral prosthesis that controls swing phase.