JP2016125284A - Construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a construction machine allowing a point of action of a work part to be easily moved along a target locus.SOLUTION: A boom is installed on an upper revolving body. An arm is installed at a tip of the boom. A work part consists of the boom and the arm. The work part is driven by a drive unit. An operation device is operated by an operator. A sensor detects a point of action of the work part. The drive unit is controlled so that the closer to a base of the boom the point of action is, the higher a ratio of an angular speed of the boom to a control input of the operation device becomes.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a construction machine that operates a boom and an arm by operating an operating device.

  Patent Document 1 below discloses a trajectory control device for a construction machine. In this trajectory control device, the boom angular velocity and the arm angular velocity are corrected so that the rotational movements of the boom and the arm are automatically stopped at the stroke ends of the boom cylinder and the arm cylinder, respectively. Thereby, a smooth continuous operation is possible even in the vicinity of the stroke ends of the boom cylinder and the arm cylinder.

JP-A-10-121507

  In a general hydraulic excavator, the angular velocities of the boom and the arm are determined according to the operation angle of the operation lever. The moving speed of the bucket tip in the vertical direction and the front-back direction has a non-linear relationship with the angular speed of the boom and arm. As an example, the ratio of the vertical speed of the bucket tip to the angular speed of the boom and arm is defined as a mechanical speed gain. This mechanical speed gain depends on the attitude of the boom and arm. For example, as the bucket approaches the base of the boom, the mechanical speed gain decreases. When the mechanical speed gain decreases, the vertical movement of the bucket with respect to the operation amount of the operation lever becomes slow.

  There is a case where an operation of moving the bucket along a target trajectory that spans regions having different mechanical speed gains may be performed. If the position of the bucket deviates from the target locus in a region where the mechanical speed gain is small, the amount of operation for returning to the target locus must be increased. Thus, since the operation amount for returning the bucket to the target locus varies, it is difficult to move the bucket along the target locus.

  An object of the present invention is to provide a construction machine that can easily move an action point of a work part along a target locus.

According to one aspect of the invention,
A work part including a boom attached to the upper swing body and an arm attached to the tip of the boom;
A driving device for driving the work component;
An operating device operated by a pilot;
A sensor for detecting a position of an action point of the work part;
There is provided a construction machine having a control device that controls the drive device so that the ratio of the angular velocity of the boom to the operation amount of the operation device becomes higher as the action point is closer to the base of the boom.

  In general, when the operating point approaches the base of the boom, the ratio of the angular velocity of the boom to the operation amount of the operating device (mechanical speed gain) decreases. The closer the operating point is to the base of the boom, the higher the mechanical speed gain is controlled, so the driver moves the operating point of the work part without being aware of the decrease in the mechanical speed gain. It becomes possible to make it. For this reason, it is easy to move an action point along a target locus.

FIG. 1 is a side view of a construction machine according to an embodiment. FIG. 2 is a schematic diagram of a hydraulic control system of the construction machine according to the embodiment. FIG. 3 is a diagram for explaining the definition of the coordinate system and various parameters for defining the posture of the work part. FIG. 4A is a graph showing an example of the locus of the action point AP when a normal driver steers, and is a graph showing the time change of the angle θ1, and FIG. 4C shows the time change of the mechanical speed gain. It is a graph. FIG. 5A is a graph showing the longitudinal position dependency of the mechanical speed gain related to the boom, and FIG. 5B is a graph showing the vertical position dependency of the mechanical speed gain related to the arm. FIG. 6 is a block diagram illustrating a function of driving a work part of the construction machine according to the embodiment. FIG. 7 is a block diagram illustrating a function of driving a work part of a construction machine according to another embodiment. FIG. 8 is a block diagram illustrating a function of driving a work part of a construction machine according to still another embodiment. FIG. 9 is a block diagram illustrating a function of driving a work part of a construction machine according to still another embodiment.

  FIG. 1 shows a side view of a construction machine according to an embodiment. An upper turning body 12 is mounted on the lower traveling body 10 via a turning mechanism 11 so as to be turnable. Working parts such as a boom 13, an arm 15, and a bucket 17 are connected to the upper swing body 12. The work parts are hydraulically driven by hydraulic cylinders such as the boom cylinder 14, the arm cylinder 16, and the bucket cylinder 18. The boom 13, the arm 15, and the bucket 17 constitute an excavation attachment. In addition to the excavating attachment, a crushing attachment, a lifting magnet attachment, and the like can be connected.

  FIG. 2 shows a schematic diagram of a hydraulic control system of a construction machine according to the embodiment. A hydraulic circuit supplies hydraulic oil to the boom cylinder 14, arm cylinder 16, and bucket cylinder 18. Furthermore, this hydraulic circuit also supplies hydraulic oil to the hydraulic motors 19, 20 and 21. The hydraulic motors 19 and 20 drive the two crawlers of the lower traveling body 10 (FIG. 1), respectively. The hydraulic motor 21 turns the upper swing body 12 (FIG. 1).

  The hydraulic circuit includes a hydraulic pump 26 and a control valve 25. The hydraulic pump 26 is driven by the power generator 35. For the power generation device 35, for example, an internal combustion engine such as a diesel engine is used. The hydraulic pump 26 supplies high-pressure hydraulic oil to the control valve 25. The control valve 25 includes a direction switching valve 251, a flow rate adjustment valve 252, a regenerative valve 253, and the like. The direction switching valve 251 switches the direction of the flow of hydraulic oil supplied to the hydraulic cylinder and the hydraulic motor. The flow rate adjustment valve 252 adjusts the flow rate of the hydraulic oil supplied to the hydraulic cylinder and the hydraulic motor. The direction switching valve 251 and the flow rate adjustment valve 252 are prepared for each hydraulic cylinder and each hydraulic motor. The regenerative valve 253 causes return oil that returns from the boom cylinder 14 or the arm cylinder 16 to the tank when the boom 13 or the arm 15 is lowered to flow into the arm cylinder 16 or the boom cylinder 14, respectively. Thereby, the flow rate of the hydraulic oil to the arm cylinder 16 or the boom cylinder 14 is boosted.

  The bottom chamber and rod chamber of the boom cylinder 14 are connected to the control valve 25 via a hydraulic line 141 and a hydraulic line 142, respectively. The bottom chamber and the rod chamber of the arm cylinder 16 are connected to the control valve 25 via a hydraulic line 161 and a hydraulic line 162, respectively. The bottom chamber and the rod chamber of the bucket cylinder 18 are connected to the control valve 25 via a hydraulic line 181 and a hydraulic line 182 respectively.

  The pressure sensors 271 and 272 measure the pressure of hydraulic oil supplied to the bottom chamber and the rod chamber of the boom cylinder 14 or discharged from the bottom chamber and the rod chamber, respectively. The pressure sensors 273 and 274 measure the pressure of the hydraulic oil supplied to the bottom chamber and the rod chamber of the arm cylinder 16 or the hydraulic oil discharged from the bottom chamber and the rod chamber, respectively. The pressure sensors 275 and 276 measure the pressure of the hydraulic oil supplied to the bottom chamber and the rod chamber of the bucket cylinder 18 or the hydraulic oil discharged from the bottom chamber and the rod chamber, respectively. Measurement results of the pressure sensors 271 to 276 are input to the control device 30.

  The operation device 31 includes an operation lever 311 operated by a pilot. The operation device 31 generates a pilot pressure or an electric signal corresponding to the operation amount OA of the operation lever 311. A pilot pressure or an electric signal corresponding to the operation amount OA is input to the control device 30.

  The control device 30 generates a command value CV for driving the hydraulic cylinder including the boom cylinder 14, the arm cylinder 16, and the bucket cylinder 18 based on the operation amount OA input from the operation device 31. Furthermore, the control device 30 generates a command value CV for driving the hydraulic motors 19 to 21 based on the operation amount OA. A pilot pressure or an electric signal corresponding to the command value CV is given to the control valve 25. A configuration may be adopted in which pilot pressure is applied to some control valves 25 and electrical signals are applied to other control valves 25. For example, a hydraulic valve may be used as the direction switching valve 251 and an electromagnetic valve may be used as the flow rate adjustment valve 252. By controlling the control valve 25 based on the command value CV, the hydraulic cylinder and the hydraulic motors 19 to 21 operate.

  The control device 30 further controls the rotational speed of the power generation device 35 and the swash plate inclination angle of the hydraulic pump 26. As a result, the amount of hydraulic oil discharged from the hydraulic pump 26 is controlled.

  With reference to FIG. 3, a coordinate system for defining the posture of the work part will be described. A boom 13 is connected to the upper swing body 12 (FIG. 1). An arm 15 is connected to the tip of the boom 13, and a bucket 17 is connected to the tip of the arm 15. When the construction machine is placed on a horizontal plane, the connection point of the boom 13 to the upper swing body 12 is the origin, the front in the horizontal direction is the positive direction of the x axis, and the vertical direction is the positive direction of the z axis. Define Cartesian coordinate system.

  The angle formed by the boom vector 130 heading from the origin to the connection point between the boom 13 and the arm 15 and the positive direction of the z-axis is represented by θ1. An angle formed by the boom vector 130 and the arm vector 150 heading from the connection point between the boom 13 and the arm 15 to the connection point between the arm 15 and the bucket 17 is represented by θ2. The angle formed by the arm vector 150 and the bucket vector 170 heading from the connection point between the arm 15 and the bucket 17 to the action point AP that is the tip of the bucket 17 is represented by θ3. The angle formed by the boom vector 130 and the action point vector 151 directed from the connection point between the boom 13 and the arm 15 to the action point AP is represented by θ4.

  The angle sensor 291 measures the angle θ1, the angle sensor 292 measures the angle θ2, and the angle sensor 293 measures the angle θ3. The angle θ4 can be calculated from the angle θ2, the angle θ3, the length of the arm vector 150, and the length of the bucket vector 170. When the work is performed with the relative positional relationship between the arm 15 and the bucket 17 fixed, that is, when the angle θ3 is constant, the angle θ4 can be calculated from the measured value of the angle θ2. The posture of the work part is specified from the angles θ1, θ2, and θ3 measured by the angle sensors 291, 292, and 293. The angle sensors 291, 292, and 293 are collectively referred to as an attitude sensor 29.

The position (x, z) of the action point AP is uniquely determined by the angle θ1, the angle θ4, the length of the boom vector 130, and the length of the action point vector 151. In other words, the angles θ1 and θ4 are obtained from the position (x, z) of the action point AP. Therefore, the angle θ1 and the angle θ4 can be expressed by the following equations using the function A and the function B.

When the angle θ3 is constant, the angular velocity of the arm 15 is equal to the angular velocity of the action point vector 151. For this reason, the angular velocity Wb of the boom and the angular velocity Wa of the arm are expressed by the following equations.

  With reference to FIGS. 4A to 4C, an example of performing an operation (horizontal pulling operation) of moving the action point AP (FIG. 3) along the horizontal plane by the construction machine according to the comparative example will be described. It is assumed that the angle θ3 (FIG. 3) is constant during the horizontal pulling operation, and the angle θ1 and the angle θ2 (FIG. 3) change. That is, the boom cylinder 14 and the arm cylinder 16 (FIG. 2) operate, and the bucket cylinder 18 (FIG. 2) does not operate.

  FIG. 4A shows an example of the locus of the action point AP when a pilot with a general skill level steers. The actual locus L of the action point AP is indicated by a solid line. In spite of the fact that the operator has operated so that the action point AP moves along the straight line of z = 0, the locus L of the action point AP is the target in the region where the action point AP is close to the base of the boom 13. It turns out that it has deviated greatly from the locus.

  FIG. 4B shows the time change of the angle θ1. The horizontal axis represents the elapsed time from the start of operation, and the vertical axis represents the angle θ1 of the boom 13. The actual change A1 in the angle θ1 is indicated by a thick solid line. For reference, an ideal change A2 of the angle θ1 of the boom 13 for moving the action point AP along the z = 0 straight line is indicated by a thin solid line. When the elapsed time exceeds t1, the angle θ1 must be decreased rapidly as indicated by the change A2, but the decrease in the angle θ1 due to actual operation is as gentle as the change A1.

  FIG. 4C shows the time change of the mechanical speed gain. The horizontal axis represents the elapsed time from the start of operation, and the vertical axis represents the mechanical speed gain. The mechanical speed gain means the ratio of the speed of the action point AP to the angular speed of the boom and arm. The mechanical speed gain includes a value related to the vertical speed of the action point AP and a value related to the speed in the front-rear direction. In FIG. 4C, the ratio of the speed in the z direction (vertical direction) of the action point AP to the boom angular speed is shown as a mechanical speed gain.

  In a time zone before the elapsed time t2, the mechanical speed gain is substantially constant. However, in the time zone after the elapsed time t2, the mechanical speed gain gradually decreases as the elapsed time increases. This means that the movement of the action point AP in the z direction becomes slow with respect to the amount of operation of the operating device by the operator. For this reason, as shown in FIG. 4A, it is considered that even if the action point AP deviates from the target locus in the vicinity of the base portion of the boom 13, the operator could not quickly return to the target locus.

  In order to move the action point AP along the target trajectory, as shown in FIG. 4B, when the elapsed time exceeds t1, the boom angle θ1 must be rapidly reduced. However, in the example shown in FIG. 4B, the decrease in the angle θ1 is more gradual than the ideal change. This means that the operator did not notice that the movement of the action point AP became slow, and the operation amount of the operation lever was changed gently.

  FIG. 5A shows the longitudinal position dependency of the mechanical speed gain regarding the boom. The horizontal axis represents the position in the front-rear direction (x coordinate), and the vertical axis represents the ratio of the speed Vz in the z direction of the action point AP to the angular speed Wb of the boom. It can be seen that the mechanical speed gain related to the boom decreases as the x coordinate decreases, that is, as the action point AP approaches the base of the boom 13. The vertical position (z coordinate) dependence of the mechanical speed gain related to the boom is smaller than the longitudinal position dependence.

  FIG. 6 shows a block diagram of a function for driving a work part of the construction machine according to the embodiment. Referring to FIG. 6, an example in which the angle θ <b> 3 (FIG. 3) of the bucket 17 is held at a constant value and the work of changing the angle θ <b> 1 (FIG. 3) of the boom 13 and the angle θ <b> 2 (FIG. 3) of the arm 15 is performed. explain.

  An operation amount OA for each boom cylinder 14, arm cylinder 16, and bucket cylinder 18 (FIG. 2) is input from the operation device 31 to the control device 30. The attitude sensor 29 detects the attitude of the work component 23 including the boom 13, the arm 15, and the bucket 17, and the detection result is input to the control device 30. The attitude sensor 29 includes angle sensors 291, 292, and 293 (FIG. 3), and the detection result of the attitude of the work part 23 includes angles θ 1, θ 2, and θ 3. Based on the angles θ1, θ2, and θ3, the x-coordinate and z-coordinate of the action point AP can be calculated.

  The driving device 33 is driven by the control device 30 to drive the work component 23. The drive device 33 includes a power generation device 35 (FIG. 2), a hydraulic circuit 34, a boom cylinder 14, an arm cylinder 16, and a bucket cylinder 18. The hydraulic circuit 34 includes a hydraulic pump 26, a control valve 25 (FIG. 2), and the like.

  The hydraulic circuit 34 operates in response to the boom control signal SCb and the arm control signal SCa from the control device 30. As a result, the flow rate of hydraulic oil commanded by the control signal SCb is supplied to the boom cylinder 14, and the flow rate of hydraulic oil commanded by the control signal SCa is supplied to the arm cylinder 16. In this embodiment, since the bucket cylinder 18 is not driven, the description of the control of the bucket cylinder 18 is omitted.

  The control device 30 controls the drive device 33 so that the ratio of the angular velocity Wb of the boom 13 to the operation amount OA of the operation device 31 increases as the action point AP (FIG. 3) is closer to the base of the boom 13. Thereby, the change of the mechanical speed gain by the position of the action point AP shown in FIG. 5 can be compensated. The ratio of the speed of the action point AP to the manipulated variable OA is referred to as “input / output speed gain”. Similarly to the mechanical speed gain, the input / output speed gain also includes those related to the vertical speed of the action point AP and those related to the front-rear direction. The control device 30 changes the ratio of the angular velocity of the boom 13 to the operation amount OA of the operation device 31 according to the position of the action point AP so that the input / output speed gain is uniform regardless of the position of the action point AP. .

  When the input / output speed gain in the vertical direction becomes uniform, the relationship between the magnitude of the operation amount OA and the vertical movement speed of the action point AP does not depend on the position of the action point AP. For this reason, even if the action point AP approaches the base of the boom 13, it becomes easy to move the action point AP along the target trajectory.

  In FIG. 5A, the ratio of the speed Vz in the z direction of the action point AP to the angular speed Wb of the boom 13 (the vertical mechanical speed gain with respect to the boom) is shown as the mechanical speed gain, but the action on the angular speed Wa of the arm 15 is shown. The speed ratio of the point AP (mechanical speed gain for the arm) also changes depending on the position of the action point AP.

  FIG. 5B shows the vertical position dependency of the mechanical speed gain for the arm. The horizontal axis represents the vertical position (z coordinate), and the vertical axis represents the mechanical speed gain in the front-rear direction related to the arm. It can be seen that the mechanical velocity gain in the front-rear direction with respect to the arm decreases as the z coordinate decreases, that is, as the position of the action point AP decreases. Therefore, it is preferable to control the drive device 33 such that the lower the position of the action point AP, the higher the ratio of the angular velocity Wa of the arm 15 to the operation amount OA of the arm 15. By performing this control, the input / output speed gain in the front-rear direction can be made to be uniform regardless of the height of the action point AP. The longitudinal position (x coordinate) dependence of the longitudinal mechanical speed gain on the arm is smaller than the vertical position (z coordinate) dependence.

  When the action point AP is moved in the front-rear direction, the input / output speed gain in the vertical direction is corrected so as to be uniform, and when the action point AP is moved in the vertical direction, the input / output speed gain in the front-rear direction is corrected. Thus, it is preferable to make it close to uniform. Thereby, the shift | offset | difference of the action point AP from the target locus | trajectory can be corrected rapidly.

  The selection of whether to correct the input / output speed gain in the up / down direction or the input / output speed gain in the front / rear direction can be performed by a selection switch provided in the operation device 31. In addition, the control device 30 may have a function of detecting the moving direction of the action point AP. In this case, whether the control device 30 corrects the input / output speed gain in the vertical direction or the input / output speed gain in the front-rear direction is automatically determined based on the detection result of the moving direction of the action point AP. select.

  Next, the process executed by the control device 30 will be described in more detail. As illustrated in FIG. 6, the control device 30 includes an operation amount detection unit 301, a position detection unit 302, a speed request value correction unit 303, a correction coefficient determination unit 304, and a drive unit 305. The function of each part is implement | achieved, for example, when a central processing unit (CPU) runs a computer program. Further, a position-correction coefficient correspondence table 306 is stored in the storage device of the control device 30. The position-correction coefficient correspondence table 306 defines the correspondence between the position of the action point AP and the correction coefficient. A correction coefficient can be obtained from the current position of the action point AP by using the position-correction coefficient correspondence table 306. Instead of the position-correction coefficient correspondence table 306, a function for obtaining a correction coefficient from the position of the action point AP may be defined.

  The operation amount detection unit 301 generates a boom angular velocity request value WRb and an arm angular velocity request value WRa based on the operation amount OA input from the operation device 31. As an example, the boom angular velocity request value WRb and the arm angular velocity request value WRa are proportional to the operation amount OA for the boom 13 and the operation amount OA for the arm 15, respectively.

  The position detection unit 302 calculates the x coordinate and the z coordinate of the action point AP from the angles θ1, θ2, and θ3 detected by the posture sensor 29. The x-coordinate and z-coordinate of the action point AP are input to the correction coefficient determination unit 304.

  The correction coefficient determination unit 304 refers to the position-correction coefficient correspondence table 306 based on the position of the action point AP, and generates a boom correction coefficient CFb and an arm correction coefficient CFa. The generated correction coefficients CFb and CFa are input to the speed request value correction unit 303.

The speed required value correction unit 303 performs a correction operation on the boom angular speed required value WRb and the arm angular speed required value WRa based on the correction coefficients CFb and CFa, thereby generating the boom angular speed command value WCb and the arm angular speed command value WCa. . Specifically, the boom angular velocity command value WCb and the arm angular velocity command value WCa are obtained by the following calculation formula.

  The drive unit 305 transmits a boom control signal SCb and an arm control signal SCa to the drive device 33 based on the boom angular velocity command value WCb and the arm angular velocity command value WCa, respectively. When the direction switching valve 251 and the flow rate adjustment valve 252 of the drive device 33 operate based on the control signals SCb and SCa, the hydraulic oil having a flow rate corresponding to the boom angular velocity command value WCb and the arm angular velocity command value WCa is supplied to the boom cylinder. 14 and arm cylinder 16. As a result, the angular velocity Wb of the boom 13 and the angular velocity Wc of the arm 15 substantially match the boom angular velocity command value WCb and the arm angular velocity command value WCa, respectively.

Next, the relationship between the position of the action point AP and the correction coefficients CFb and CFa will be described. As shown in FIG. 4A, since it is necessary to correct the shift of the action point AP in the z direction in the horizontal pulling operation, attention is paid to the speed of the action point AP in the z direction. In Expression (2), the speed in the x direction is set to zero as a constraint condition. When dx / dt = dz / dt = 0 in the equation (2), the following equation is obtained.

The mechanical speed gains MGb and MGa related to the angular speed Wb of the boom 13 and the angular speed Wa of the arm 15 are expressed by the following formula based on the formula (4).

ここで、Ｃｂ及びＣａは定数である。 The correction coefficients CFb and CFa are determined so as to satisfy the following expressions.

Here, Cb and Ca are constants.

Since the boom cylinder 14 and the arm cylinder 16 operate so that the angular velocity Wb of the boom 13 and the angular velocity Wa of the arm 15 coincide with the boom angular velocity command value WCb and the arm angular velocity command value WCa, respectively, Wb = WCb, Wa = WCa It can be assumed that it is satisfied. Under this condition, the velocity of the action point AP in the z direction is expressed by the following equation based on the equations (5), (3), and (6).

  As can be seen from Expression (7), the speed Vz in the z direction of the action point AP is proportional to the boom angular speed request value WRb and the arm angular speed request value WRa. The correction coefficients CFb and CFa can be determined based on the equations (5) and (6). Since the functions gb (x, z) and ga (x, z) on the right side of Expression (5) are functions of the position (x, z) of the action point AP, the correction coefficients CFb and CFa are the positions of the action point AP. Depends on.

The boom angular speed request value WRb and the arm angular speed request value WRa are generated according to the operation amount OAb of the boom 13 and the operation amount OAa of the arm 15, respectively, and are proportional to the operation amounts OAb and OAa. Therefore, the boom angular velocity request value WRb and the arm angular velocity request value WRa can be expressed by the following equations.

Here, C1a and C1b are proportional constants. From the equations (7) and (8), the speed of the action point AP is expressed by the following equation.

  The constant Cb × C1b and the constant Ca × C1a in Expression (9) correspond to the input / output speed gain. That is, the input / output speed gain is a constant value. In this way, by correcting the input / output speed gain defined by the ratio of the moving speed of the action point AP with respect to the manipulated variable OA using the correction coefficients CFb and CFa depending on the position of the action point AP, the input / output speed is corrected. Gain can be close to a certain value.

  In the above embodiment, the ratio of the speed in the z direction (vertical direction) of the action point AP with respect to the operation amount OA is used as the input / output speed gain. By making this input / output speed gain close to a constant value, it is possible to reduce the deviation of the action point AP from the target locus in the horizontal pulling operation. When the action point AP is moved along a trajectory other than the horizontal direction, a direction other than the z direction may be adopted as the speed direction of the action point AP that is the basis of the input / output speed gain. For example, when the action point AP is moved in the vertical direction, it is preferable to use the ratio of the speed in the x direction (front-rear direction) of the action point AP to the operation amount OA as the input / output speed gain.

  In the above embodiment, the action point AP is moved under the condition that the angle θ3 (FIG. 3) related to the bucket 17 is kept constant, but the angle θ3 may be changed during operation. When moving the action point AP in the horizontal direction or the vertical direction, the bucket cylinder 18 (FIG. 1) may be operated to change the angle θ3.

  When the bucket cylinder 18 is operated, the input / output speed gain includes the first input / output speed gain defined by the ratio of the moving speed of the action point AP to the boom operation amount and the action point AP to the arm operation amount. A second input / output speed gain defined by the ratio of the moving speed and a third input / output speed gain defined by the ratio of the moving speed of the action point AP to the operation amount of the bucket are included. Based on the command value CV, the control device 30 determines at least one of the first input / output speed gain, the second input / output speed gain, and the third input / output speed gain based on the position of the action point AP. to correct. As an example, it is preferable that an input / output speed gain (before correction) that varies most greatly depending on the position of the action point AP is to be corrected. Thereby, the input / output speed gain to be corrected can be made uniform regardless of the position of the action point AP.

  Next, with reference to FIG. 7, the control method of the work components of the construction machine by another Example is demonstrated. Hereinafter, differences from the embodiment shown in FIGS. 1 to 6 will be described, and description of common configurations will be omitted.

  FIG. 7 shows a block diagram of a function for driving a work part of a construction machine. The control device 30 according to the embodiment shown in FIG. 7 has a discharge amount correction unit 307 instead of the speed request value correction unit 303 (FIG. 6). The boom angular velocity request value WRb and the arm angular velocity request value WRa generated by the operation amount detection unit 301 are directly input to the drive unit 305. The drive unit 305 outputs a boom control signal SCb and an arm control signal SCa based on the boom angular speed request value WRb and the arm angular speed request value WRa.

  The discharge amount correction unit 307 generates a discharge amount command value DQC based on correction coefficients CFb and CFa that depend on the position of the action point AP. Based on the discharge amount command value DQC, the drive unit 305 controls the rotational speed of the power generation device 35 so that the discharge amount of hydraulic oil from the hydraulic pump 26 (FIG. 2) matches the discharge amount command value DQC. .

  In the embodiment shown in FIG. 7, the angular velocity Wb of the boom 13 and the angular velocity Wa of the arm 15 are adjusted by controlling the discharge amount of the hydraulic oil from the hydraulic pump 26. The discharge amount of the hydraulic oil from the hydraulic pump 26 is controlled so that the actual angular velocities Wb and Wa are equal to the boom angular velocity command value WCb and the arm angular velocity command value WCa of the embodiment shown in FIG. Thereby, similarly to the embodiment shown in FIG. 6, the input / output speed gain can be made close to a constant value without depending on the position of the action point AP.

  As an example, the input / output speed gain can be increased by relatively increasing the discharge amount in a state where the action point AP is located in a region where the mechanical speed gain is relatively small. As a result, the input / output speed gain can be brought close to a constant value.

  In the embodiment shown in FIG. 7, the discharge amount of hydraulic oil is adjusted by controlling the rotational speed of the power generator 35, but by changing the inclination angle of the swash plate of the hydraulic pump 26 (FIG. 2). The discharge amount may be adjusted.

  Next, with reference to FIG. 8, a method for controlling a work part of a construction machine according to still another embodiment will be described. Hereinafter, differences from the embodiment shown in FIG. 7 will be described, and descriptions of common configurations will be omitted.

  FIG. 8 shows a block diagram of a function for driving a work part of a construction machine. The control device 30 according to the embodiment shown in FIG. 8 includes a regenerative flow rate correction unit 308 instead of the discharge amount correction unit 307 (FIG. 7).

  The regenerative flow rate correction unit 308 generates a regenerative flow rate command value RFC based on correction coefficients CFb and CFa that depend on the position of the action point AP. The drive unit 305 controls the regenerative valve 253 (FIG. 2) based on the regenerative flow rate command value RFC. For example, when the arm 15 descends, the boom cylinder 14 can be boosted by causing the return oil that returns from the arm cylinder 16 to the tank to flow into the boom cylinder 14. Thereby, it is possible to compensate for a decrease in the mechanical speed gain defined by the ratio of the speed of the action point AP to the angular speed of the boom 13.

  Conversely, when it is necessary to compensate for the decrease in the mechanical speed gain defined by the ratio of the speed of the action point AP to the angular speed of the arm 15, the return oil that returns from the boom cylinder 14 to the tank when the boom 13 descends. The arm cylinder 16 may be boosted by flowing the gas into the arm cylinder 16. In this way, by controlling the regenerative valve 253 and adjusting the direction and flow rate of the hydraulic oil flowing through the regenerative line, the input / output speed gain can be brought close to a constant value.

  Next, with reference to FIG. 9, a method for controlling a work part of a construction machine according to still another embodiment will be described. Hereinafter, differences from the embodiment shown in FIG. 8 will be described, and descriptions of common configurations will be omitted.

  FIG. 9 shows a block diagram of a function for driving a work part of a construction machine. In the embodiment illustrated in FIG. 9, the control device 30 includes a load determination unit 309. Detection results of the pressure sensors 271 to 276 (FIG. 2) are input to the load determination unit 309.

  The load determination unit 309 calculates a load applied to the action point AP based on the pressures of the boom cylinder 14, the arm cylinder 16, and the bucket cylinder 18 detected by the pressure sensors 271 to 276. Further, based on the load applied to the action point AP, it is determined whether the current work is a no-load work or a loaded work. For example, when the load (or reaction force) applied to the action point AP is less than the determination reference value, it is determined that the current work is no-load work, and when the load is greater than the determination reference value, the current work is load work. Determined.

  When the current work is a no-load work, the regenerative flow rate command value RFC generated by the regenerative flow rate correction unit 308 is input to the drive unit 305. When the current work is a load work, the regenerative flow rate command value RFC generated by the regenerative flow rate correction unit 308 is not input to the drive unit 305. In other words, when the current work is a no-load work, the function for correcting the input / output speed gain is enabled, and when the current work is a load work, the function for correcting the input / output speed gain is disabled. To be.

  In the embodiment shown in FIG. 8, the return oil that returns to the tank from one of the arm cylinder 16 and the boom cylinder 14 flows into the other through the regeneration line. Thereby, the input / output speed gain can be made close to a constant value regardless of the position of the action point AP, but the excavation force may be reduced.

  In the embodiment shown in FIG. 9, since the function of correcting the input / output speed gain is disabled during a load operation such as excavation, it is possible to prevent a decrease in excavation force. When a no-load operation such as a horizontal pulling operation is performed, the function of correcting the input / output speed gain is enabled, so that the difference between the locus of the action point AP and the target locus can be reduced.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

DESCRIPTION OF SYMBOLS 10 Lower traveling body 11 Turning mechanism 12 Upper turning body 13 Boom 14 Boom cylinder 15 Arm 16 Arm cylinder 17 Bucket 18 Bucket cylinders 19, 20, 21 Hydraulic motor 23 Work part 25 Control valve 26 Hydraulic pump 29 Attitude sensor 30 Control device 31 Operation Device 33 Drive device 34 Hydraulic circuit 35 Power generator 130 Boom vector 141, 142 Hydraulic line 150 Arm vector 151 Action vector 161, 162 Hydraulic line 170 Bucket vector 181, 182 Hydraulic line 251 Directional switching valve 252 Flow rate adjusting valve 253 Regenerative valve 271, 272, 273, 274, 275, 276 Pressure sensor 291, 292, 293 Angle sensor 301 Operation amount detection unit 302 Position detection unit 303 Speed request value correction unit 304 Correction coefficient determination unit 305 Drive unit 06 Position-correction coefficient correspondence table 307 Discharge amount correction unit 308 Regenerative flow rate correction unit 309 Load determination unit 311 Operation lever AP Action point CFa, CFb Correction coefficient CV Command value CVa Arm command value CVb Boom command value DQC Discharge amount command value L Trajectory MGa, MGb Mechanical speed gain OA Operation amount OAa Arm operation amount OAb Boom operation amount RFC Regenerative flow rate command value SCa, SCb Control signal Vz Z-direction speed WCa Arm angular velocity command value WCb Boom angular velocity command value WRa Arm Angular speed request value WRb Boom angular speed request values Wa, Wb, Wc Angular speed

Claims (13)

A work part including a boom attached to the upper swing body and an arm attached to the tip of the boom;
A driving device for driving the work component;
An operating device operated by a pilot;
A sensor for detecting a position of an action point of the work part;
A construction machine comprising: a control device that controls the drive device such that the closer the action point is to the base of the boom, the higher the ratio of the angular velocity of the boom to the operation amount of the operation device is.   2. The construction machine according to claim 1, wherein the control device controls the drive device such that a ratio of an angular velocity of the arm to the operation amount is higher as the action point is closer to a base of the boom. A work part including a boom attached to the upper swing body and an arm attached to the tip of the boom;
A driving device for driving the work component;
An operating device operated by a pilot;
A sensor for detecting a position of an action point of the work part;
A control device that controls the drive device based on an operation amount input from the operation device;
The construction device corrects a speed gain defined by a ratio of a moving speed of the action point to an operation amount of the operating device based on a position of the action point detected by the sensor.   The construction machine according to claim 3, wherein the control device brings the speed gain close to a constant value regardless of the position of the action point.   The construction machine according to claim 3 or 4, wherein the speed gain is defined by a ratio of a moving speed of the action point in a vertical direction with respect to an operation amount of the operating device.   The construction machine according to claim 3 or 4, wherein the speed gain is defined by a ratio of a moving speed in the front-rear direction of the action point with respect to an operation amount of the operating device. The speed gain is a vertical speed gain defined by a ratio of a moving speed of the operating point in the vertical direction with respect to an operation amount of the operating device, and a movement of the operating point in the front-rear direction with respect to the operating amount of the operating device. Including the longitudinal speed gain defined by the speed ratio,
The controller is
Select one speed gain from the vertical speed gain and the front-rear speed gain,
The construction machine according to claim 3 or 4, wherein the selected speed gain is corrected based on a position of the action point detected by the sensor. The controller is
A speed request value is generated based on the operation amount,
A speed command value is generated by performing a correction operation depending on the position of the action point with respect to the speed request value,
The construction machine according to claim 3, wherein the driving device is controlled based on the speed command value. The driving device includes:
A boom cylinder for driving the boom;
An arm cylinder for driving the arm;
A hydraulic pump that discharges hydraulic oil;
A control valve for adjusting the flow of the hydraulic oil from the hydraulic pump to the boom cylinder and the arm cylinder;
A power generator for driving the hydraulic pump,
The construction machine according to claim 8, wherein the control device corrects the speed gain by controlling the control valve based on the speed command value. The work part further includes a bucket attached to a tip of the arm,
The drive device further includes a bucket cylinder that drives the bucket,
The control valve further adjusts the flow of the hydraulic oil to the bucket cylinder,
The speed gain is defined by a first speed gain defined by a ratio of a moving speed of the action point to the operation amount of the boom and a ratio of a moving speed of the action point to the operation amount of the arm. A second speed gain and a third speed gain defined by a ratio of a moving speed of the action point to the operation amount of the bucket;
The control device corrects at least one of the first speed gain, the second speed gain, and the third speed gain based on the position of the action point based on the speed command value. The construction machine according to claim 9. The driving device includes:
A boom cylinder for driving the boom;
An arm cylinder for driving the arm;
A hydraulic pump that discharges hydraulic oil;
A control valve for adjusting the flow of the hydraulic oil from the hydraulic pump to the boom cylinder and the arm cylinder;
A power generator for driving the hydraulic pump,
The controller is
Controlling the control valve based on the speed requirement value;
The construction machine according to claim 8, wherein the speed gain is corrected by controlling a discharge amount of the hydraulic oil from the hydraulic pump based on a position of the action point detected by the sensor. The driving device includes:
A boom cylinder for driving the boom;
An arm cylinder for driving the arm;
A hydraulic pump that discharges hydraulic oil;
A flow rate adjusting valve for adjusting the flow of the hydraulic oil from the hydraulic pump to the boom cylinder and the arm cylinder;
A power generator for driving the hydraulic pump;
A regenerative line for allowing return oil to return to the tank from one of the boom cylinder and the arm cylinder to the other;
Including a regenerative valve provided in the regenerative line,
The controller is
Controlling the flow rate regulating valve based on the speed requirement value;
The construction machine according to claim 8, wherein the speed gain is corrected by controlling the regenerative valve based on the position of the action point detected by the sensor. The control device determines whether the current work, no-load work or loaded work based on the load applied to the action point;
If the current work is the no-load work, enable the function to correct the speed gain,
The construction machine according to any one of claims 3 to 12, wherein when the current work is the load work, the function of correcting the speed gain is invalidated.

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