WO2022054946A1 - Robot device and control method for same - Google Patents

Abstract

A robot device according to the present disclosure includes: two links coupled via a joint; a pair of artificial muscles that are supplied with a liquid and cause the two links to rotate in a relative manner; a liquid pressure adjustment device that adjusts the pressure of the liquid supplied to the artificial muscles; and a control device. The control device includes a target rigidity setting unit that sets a target rigidity of the joint, and sets a target pressure of the liquid supplied to the artificial muscles on the basis of the target rigidity, and controls the liquid pressure adjustment device such that the pressure of the liquid supplied to the artificial muscles attains the target pressure. As a result, the robot device including the two links coupled via the joint and the pair of artificial muscles actuated by the liquid supplied can be actuated in a responsive and stable manner.

Description

Robot device and its control method

The present disclosure relates to a robot device including an artificial muscle that operates by receiving a liquid supply and a control method thereof.

Conventionally, a link that is rotatably connected to a substrate via a joint and a driving force that pulls the link in opposite directions to the substrate are generated to apply torque to the joint due to the difference in the driving force, and the driving force is applied. A robot device including a pair of pneumatic artificial muscle actuators that impart rigidity to a joint by summing is known (see, for example, Patent Document 1). The control device of this robot device calculates the driving force command value of each actuator required to make the joint rigidity the target rigidity and to make the joint angle of the joint follow the target trajectory. Then, the control device controls each actuator so that the driving force (contraction force) generated in each actuator becomes the corresponding driving force command value.

Japanese Patent No. 5930753

However, in the above-mentioned conventional robot device, it is not easy to control the pneumatic artificial muscle actuator with high accuracy, and further, the driving force (contraction force) generated in the pneumatic artificial muscle actuator approaches the driving force command value. It takes time. For this reason, in the above robot device, it becomes difficult to bring the rigidity of the joint close to the target rigidity with good responsiveness and high accuracy, and it becomes impossible to obtain the force requested from the artificial muscle with good responsiveness, or the operation of the robot device is unsuccessful. It may become stable.

Therefore, the present disclosure is responsive to a robotic device including two links connected via joints and a pair of artificial muscles that operate upon supply of liquid and rotate the two links relative to each other. The main purpose is to operate it well and stably.

The robot device of the present disclosure includes two links connected via joints, a pair of artificial muscles that receive a liquid supply and rotate the two links relatively, and the artificial muscles that are supplied to the artificial muscles. It includes a hydraulic pressure adjusting device that adjusts the pressure of the liquid and a target rigidity setting unit that sets the target rigidity of the joint, and sets the target pressure of the liquid supplied to the artificial muscle based on the target rigidity, and also sets the target pressure of the liquid. It includes a control device that controls the hydraulic pressure adjusting device so that the pressure of the liquid supplied to the artificial muscle becomes the target pressure.

The robotic apparatus of the present disclosure operates by receiving a liquid supply, and has a pair of artificial muscles that relatively rotate two links connected via joints, and the pressure of the liquid supplied to the artificial muscles. A hydraulic pressure adjusting device for adjusting the hydraulic pressure and a control device for controlling the hydraulic pressure adjusting device are included. Further, the control device includes a target rigidity setting unit for setting the target rigidity of the joint. That is, the force to be output from the artificial muscle to rotate the two links relatively can be determined from the target rigidity of the joint connecting the two links. Then, if the target pressure of the hydraulic pressure to the artificial muscle is set based on the target rigidity and the hydraulic pressure adjusting device is controlled based on the target pressure, the artificial muscle is responsive so as to output the required force. It is possible to operate it with high accuracy. As a result, the rigidity of the joint can be changed with high accuracy in a responsive manner, so that the rigidity of the joint can be reduced to allow the required torque output, or the joint can be stabilized in the operation of the robot device. It is possible to increase the rigidity of the. As a result, the robot device including two links connected via joints and a pair of artificial muscles that operate by receiving a liquid supply and rotate the two links relatively is responsive and stable. Can be activated.

The control method of the robot apparatus of the present disclosure is to supply two links connected via joints, a pair of artificial muscles that receive a liquid supply and rotate the two links relatively, and the artificial muscles. A method of controlling a robot device including a hydraulic pressure adjusting device for adjusting the pressure of the liquid, wherein the target rigidity of the joint is set and the liquid supplied to the artificial muscle based on the target rigidity. A target pressure is set, and the hydraulic pressure adjusting device is controlled so that the pressure of the liquid supplied to the artificial muscle becomes the target pressure.

According to such a method, a robot device including two links connected via joints and a pair of artificial muscles that operate by receiving a liquid supply and rotate the two links relatively is responsive. It can be operated well and stably.

It is a schematic block diagram which shows the robot apparatus of this disclosure. It is an enlarged view which shows the robot apparatus of this disclosure. It is a schematic block diagram which shows the liquid supply apparatus of the robot apparatus of this disclosure. It is a block diagram which shows the control device of the robot apparatus of this disclosure. It is a flowchart which illustrates the control procedure of the robot apparatus of this disclosure. It is a flowchart which illustrates the control procedure of the robot apparatus of this disclosure. It is a flowchart illustrating the control procedure of the robot apparatus of this disclosure. It is a flowchart illustrating the control procedure of the robot apparatus of this disclosure. It is explanatory drawing which illustrates the target pressure setting map. It is a time chart which shows the operating state of the robot apparatus of this disclosure. It is a flowchart which illustrates the control procedure of the robot apparatus of this disclosure. It is a flowchart which illustrates the control procedure of the robot apparatus of this disclosure. It is a block diagram which shows the other control apparatus applicable to the robot apparatus of this disclosure. It is a flowchart illustrating the control procedure of the robot apparatus by the control apparatus of FIG. It is a flowchart illustrating the control procedure of the robot apparatus by the control apparatus of FIG. It is explanatory drawing which illustrates the 1st and 2nd target pressure setting maps. It is a flowchart illustrating the control procedure of the robot apparatus by the control apparatus of FIG. It is explanatory drawing which illustrates the volume estimation map. It is explanatory drawing which illustrates the current command value setting map.

Next, a mode for carrying out the invention of the present disclosure will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing the robot device 1 of the present disclosure, and FIG. 2 is an enlarged view showing the robot device 1. The robot device 1 shown in these drawings includes a robot arm (robot body) 2, a liquid supply device (fluid supply device) 10, and a control device 100 that controls the entire device. The robot arm 2 includes a plurality of (three in this embodiment) joints (pin joints) J1, J2, J3, a plurality of (three in this embodiment) arms (links) 3, and joints J1, A plurality of hydraulic actuators (fluid actuators) M as artificial muscles provided for each of J2 and J3, for example, an even number (four in this embodiment), and a hand portion as a gripping portion attached to the arm 3 on the tip side. It is an articulated arm including (robot hand) 4. The hand unit 4 is controlled by the control device 100 so as to grip the target object (hereinafter, referred to as “grasping target”). Further, the liquid supply device 10 is controlled by the control device 100 to supply and discharge hydraulic oil (working fluid) as a liquid to each hydraulic actuator M. As a result, the robot arm 2 can be driven hydraulically (hydraulic pressure) to move the hand portion 4 to a desired position.

As shown in FIG. 2, each hydraulic actuator M of the robot arm 2 is a so-called Macchiben type artificial muscle including a tube T that expands and contracts by the pressure of hydraulic oil and a braided sleeve S that covers the tube T. be. The tube T is formed in a cylindrical shape by an elastic material such as a rubber material having high oil resistance, and both ends of the tube T are sealed by a sealing member C. A hydraulic oil inlet / outlet IO is formed on the sealing member C on the base end side (liquid supply device 10 side, lower end side in FIG. 2) of the tube T. The braided sleeve S is formed in a cylindrical shape by knitting a plurality of cords oriented in a predetermined direction so as to intersect each other, and is retractable in the axial direction and the radial direction. As the cord forming the braided sleeve S, a fiber cord, a high-strength fiber, a metal cord composed of ultrafine filaments, or the like can be adopted. By supplying hydraulic oil from the inlet / outlet IO into the tube T of the hydraulic actuator M to increase the pressure of the hydraulic oil in the tube T, the tube T expands in the radial direction due to the action of the braided sleeve S and the shaft. It contracts in the direction and generates a contraction force according to the pressure of the hydraulic oil inside.

As shown in FIGS. 1 and 2, of the plurality of arms 3, the arm 3 on the most proximal end side (most liquid supply device 10 side) is rotatable by the support member 5 as a link via the joint J1. Be supported. Further, the two arms 3 are rotatably connected to each other via the joint J2 or J3. Further, the connecting member 6 is fixed to the tip ends (ends on the hand side) of the two arms 3 on the liquid supply device 10 side. As shown in the figure, the support member 5 rotatably supports the sealing member C on the proximal end side of the plurality (four) hydraulic actuators M corresponding to the joint J1 on the distal end side. Further, each connecting member 6 rotatably supports the sealing member C on the tip end side (hand side) of the plurality (four) hydraulic actuators M corresponding to the joints J1 or J2 located on the proximal end side. .. Further, each connecting member 6 rotatably supports the sealing member C on the proximal end side of the plurality (four) hydraulic actuators M corresponding to the joints J2 or J3 located on the distal end side.

More specifically, the support member 5 rotatably supports the sealing member C on the proximal end side of the two hydraulic actuators M corresponding to the joint J1 via the first connecting shaft. Further, the connecting member 6 of the arm 3 on the most proximal end side rotatably supports the sealing member C on the tip end side of the two hydraulic actuators M corresponding to the joint J1 via the second connecting shaft. .. Further, the support member 5 can rotate the sealing member C on the proximal end side of the remaining two hydraulic actuators M corresponding to the joint J1 via the third connecting shaft extending in parallel with the first connecting shaft. Support. Further, the connecting member 6 of the arm 3 on the most proximal end side extends the sealing member C on the tip end side of the remaining two hydraulic actuators M corresponding to the joint J1 in parallel with the second connecting shaft. It is rotatably supported via a connecting shaft. Similarly, the connecting member 6 of the two arms 3 connected to each other via the joint J2 or J3 also has a plurality (four) corresponding to the joint J2 or J3 via the plurality of connecting shafts as described above. The corresponding sealing member C of the hydraulic actuator M is rotatably supported.

As a result, two hydraulic actuators M are arranged in parallel with the corresponding arms 3 in the present embodiment on both sides of each arm 3 extending from the joint axis of the joints J1-J3 to the hand side (hand portion 4 side). To. Then, the two hydraulic actuators M arranged on one side of each arm 3 constitute a first artificial muscle (one antagonist muscle) AM1 (see FIG. 3) corresponding to one joint J1, J2 or J3. The two hydraulic actuators M arranged on the other side of each arm 3 are the second artificial muscles (the other) corresponding to one joint J1, J2 or J3 paired with the first artificial muscle AM1. Antagonist muscle) constitutes AM2 (see FIG. 3). However, the first and second artificial muscles AM1 and AM2 may each be composed of a single hydraulic actuator M, and the number of hydraulic actuators M constituting the first artificial muscle AM1 and the second The number of hydraulic actuators M constituting the artificial muscle AM2 may be different. Further, in the present embodiment, the plurality (four) hydraulic actuators M provided for one joint J1, J2 or J3 have the same specifications. However, the specifications of the plurality of hydraulic actuators M corresponding to one joint J1, J2 or J3 do not necessarily have to be the same. For example, the specifications of the hydraulic actuator M constituting the first artificial muscle AM1. And the specifications of the hydraulic actuator M constituting the second artificial muscle AM2 may be different. Further, each arm 3 is formed to be hollow, and a plurality of hoses H (see the broken line in FIG. 2) as a liquid supply pipe are arranged inside each arm 3. Each hose H is connected to an inlet / outlet IO formed in a sealing member C on the base end side of the corresponding hydraulic actuator M, and a liquid supply device is provided in the tube T of each hydraulic actuator M via the hose H. The hydraulic oil (hydraulic pressure) from 10 is supplied.

Therefore, by controlling the liquid supply device 10 by the control device 100, the hydraulic pressure in the tube T of the two hydraulic actuators M constituting the first artificial muscle AM1 is paired with the first artificial muscle AM1. The hydraulic pressure in the tube T of the two hydraulic actuators M constituting the artificial muscle AM2 of 2 can be made different from each other. As a result, a force (rotational torque) is transmitted from the four hydraulic actuators M, that is, the paired (pair) of the first and second artificial muscles AM1 and AM2 to each arm 3 via the connecting member 6, and supported. It is possible to change the joint angle of the joints J1-J3 by rotating each arm 3 with respect to the member 5 or the arm 3 on the proximal end side. In the present embodiment, the two hydraulic actuators M constituting the first artificial muscle AM1 and the two hydraulic actuators M constituting the second artificial muscle AM2 paired with the first artificial muscle AM1 are The tube T is antagonistically driven by hydraulic pressure from the liquid supply device 10 with a state in which the tube T contracts in the axial direction by a predetermined amount (for example, about 10% of the natural length) as an initial state.

As shown in FIG. 1, the liquid supply device 10 of the robot device 1 has a tank 11 that defines a hydraulic oil storage section (liquid storage section) and a rotating shaft that extends the tank 11 in the vertical direction (one point in FIG. 1). Includes a base portion 12 that rotatably supports around the chain wire). The tank 11 is, for example, a cylinder whose upper end and lower end are closed, and can store hydraulic oil inside. In the present embodiment, as shown in FIG. 2, the support member 5 of the robot arm 2 is fixed to the upper wall portion 11u of the tank 11 via a bolt or the like (not shown). That is, the robot arm 2 is supported by the tank 11 (upper wall portion 11u) of the liquid supply device 10.

The base portion 12 is fixed to the installation location of the robot device 1 so as to be located below the robot arm 2 and the tank 11, or is mounted (fixed) on an automatic guided vehicle (AGV or AMR) (not shown). Further, the base portion 12 supports a rotation unit (not shown) that rotates the tank 11 around the rotation shaft. As a result, by operating the rotation unit, the robot arm 2 and the tank 11 can be integrally rotated around the rotation shaft. The rotating unit may be a swing motor driven by hydraulic pressure supplied from the liquid supply device 10, or may include an electric motor or the like.

Further, as shown in FIG. 3, the liquid supply device 10 includes a pump 13 as a liquid supply source, a valve body (not shown) arranged in the tank 11, and a main pressure generation, in addition to the tank 11 and the base portion 12. The valve 14, the first and second linear solenoid valves 151 and 152 as a plurality of pressure regulating valves (hydraulic pressure adjusting devices), and the first and second supply shutoff valves 161, 162 as a plurality of supply cutoffs, respectively. including. The pump 13, the first and second linear solenoid valves 151, 152 and the first and second supply isolation valves 161, 162 are all controlled by the control device 100. The first and second linear solenoid valves 151 and 152 and the first and second supply cutoff valves 161, 162 are provided one by one for each of the joints J1, J2 and J3.

The pump 13 is, for example, an electric pump, which sucks the hydraulic oil stored in the tank 11 and discharges it from the discharge port. The pump 13 includes a pump unit arranged in the tank 11 and a drive unit having an electric motor and a reduction gear mechanism and arranged in the tank 11 or outside the tank 11. The main pressure generation valve 14 drains (adjusts) a part of the hydraulic oil discharged from the pump 13 according to the signal pressure from the signal pressure generation valve (not shown) to generate the main pressure, and the main pressure is generated in the valve body. It is supplied to the oil passage (liquid passage) L0 formed in. As the signal pressure generation valve of the main pressure generation valve 14, for example, a linear solenoid valve whose energization is controlled by the control device 100 is used.

The first and second linear solenoid valves 151 and 152 include a solenoid portion 15e and a spool 15s whose energization is controlled by the control device 100, a spring SP for urging the spool 15s to the solenoid portion 15e side (upper side in FIG. 3), and the like. , Placed inside the valve body. Further, the first and second linear solenoid valves 151 and 152 have an input port 15i communicating with the oil passage L0 of the valve body, an output port 15o communicating with the input port 15i, and a feedback port 15f communicating with the output port 15o. And a drain port 15d that can communicate with the output port 15o.

In the present embodiment, the first and second linear solenoid valves 151 and 152 are normally closed valves that open when a current is supplied to the solenoid portion 15e, and each solenoid portion 15e responds to the applied current. The spool 15s is moved in the axial direction. As a result, the thrust applied to the spool 15s from the solenoid portion 15e by supplying power to the solenoid portion 15e (coil), the urging force of the spring SP, and the hydraulic pressure supplied from the output port 15o to the feedback port 15f to the spool 5s. By balancing the thrust toward the acting solenoid portion 15e, the hydraulic oil supplied from the main pressure generation valve 14 (pump 13) side to the input port 15i and flowing out from the output port 15o is regulated to a desired pressure. Can be done. Further, as shown in FIG. 3, the drain ports 15d of the first and second linear solenoid valves 151 and 152 communicate with the hydraulic oil storage portion in the tank 11 via the oil passage L3, respectively.

The first and second supply cutoff valves 161, 162 are solenoid spool valves (solenoid valves) having the same structure as each other, and as shown in FIG. 3, the input port 16i, the first and second output ports 16oa, A sleeve having 16 obs, a spool (not shown) slidably (movably) arranged in the sleeve in the axial direction, an electromagnetic unit 16e controlled by the control device 100 to move the spool, and a spool electromagnetically. Each includes a spring (not shown) for urging the portion 16e side. The input port 16i of the first supply cutoff valve 161 is connected to the output port 15o of the first linear solenoid valve 151 via an oil passage formed in the valve body, and the input port 16i of the second supply cutoff valve 162 is a valve. It is connected to the output port 15o of the second linear solenoid valve 152 via an oil passage formed in the body.

Further, the first output port 16oa of the first supply isolation valve 161 is an inlet / outlet IO for hydraulic oil of one hydraulic actuator M (tube T) constituting the corresponding first artificial muscle AM1 via the oil passage L11. Connected to. Further, the second output port 16ob of the first supply isolation valve 161 is connected to the inlet / outlet IO of the hydraulic oil of the other hydraulic actuator M (tube T) constituting the first artificial muscle AM1 via the oil passage L12. Will be done. Further, the first output port 16oa of the second supply cutoff valve 162 is an inlet / outlet IO for hydraulic oil of one hydraulic actuator M (tube T) constituting the corresponding second artificial muscle AM2 via the oil passage L21. Connected to. Further, the second output port 16ob of the second supply cutoff valve 162 is connected to the inlet / outlet IO of the hydraulic oil of the other hydraulic actuator M (tube T) constituting the second artificial muscle AM2 via the oil passage L22. Will be done.

In the present embodiment, the first and second supply cutoff valves 161, 162 are in a complete communication state, a first partial communication state, a second partial communication state, and a complete cutoff state according to the current supplied to the electromagnetic unit 16e. Form selectively. When the first and second supply cutoff valves 161, 162 form a perfect communication state, both the input port 16i and the first and second output ports 16oa and 16ob communicate with each other. When the first and second supply cutoff valves 161, 162 form the first partial communication state, the input port 16i and the second output port 16ob communicate with each other, and the input port 16i and the first output port 16oa communicate with each other. Is blocked. When the first and second supply cutoff valves 161, 162 form the second partial communication state, the input port 16i and the first output port 16oa communicate with each other, and the input port 16i and the second output port 16ob communicate with each other. Is blocked. When the first and second supply cutoff valves 161, 162 form a complete cutoff state, the communication between the input port 16i and the first and second output ports 16oa and 16ob is cut off.

The control device 100 of the robot device 1 includes a microcomputer including a CPU, ROM, RAM, an input / output interface, and various logic ICs (all of which are not shown). The control device 100 includes a main pressure sensor (not shown) that detects the pressure of the hydraulic oil in the oil passage L0 on the upstream side of the first and second linear solenoid valves 151 and 152, the first and second linear solenoid valves 151 and 152, and the first. 1. Input the detection value of a voltage sensor (not shown) that detects the voltage of the power supply of the second supply cutoff valves 161, 162. The control device 100 controls the duty of the pump 13 so that the hydraulic pressure in the oil passage L0 detected by the main pressure sensor becomes a target value, and is supplied to the electromagnetic part of the signal pressure generation valve of the main pressure generation valve 14. Control the current.

Further, the control device 100 has a current from the first and second linear solenoid valves 151 and 152 to the first and second linear solenoid valves 151 and 152 so that the hydraulic pressure corresponding to the request is supplied to each hydraulic actuator M. A command value is set, and the current supplied to each solenoid unit 15e is controlled based on the current command value. Further, the control device 100 basically supplies a current to each solenoid unit 16e so that the first and second supply isolation valves 161, 162 form the above-mentioned complete communication state while the robot device 1 is operated. To control. Further, the control device 100 includes a current detecting unit that detects a current flowing through the solenoid portion 15e of the first linear solenoid valve 151 and a current detecting unit that detects a current flowing through the solenoid portion 15e of the second linear solenoid valve 152. (Neither is shown), the current detected by each current detector is monitored.

Further, the control device 100 first and second so as to form the first partial communication state or the second partial communication state according to the detection value from the pressure sensor (not shown) that detects the hydraulic pressure in each hydraulic actuator M. Controls the applicable supply shutoff valves 161, 162. As a result, when hydraulic oil flows out from one of the two hydraulic actuators M corresponding to any of the first and second linear solenoid valves 151 and 152 due to damage or the like, the other of the two hydraulic actuators M is affected. It is possible to continuously supply the hydraulic oil to suppress the disturbance of the behavior of the robot arm 2 and to satisfactorily suppress the further outflow of the hydraulic oil from the damaged hydraulic actuator M. Further, by controlling the corresponding ones of the first and second supply shutoff valves 161, 162 so as to form a complete shutoff state by the control device 100, the first or second linear solenoid valves 151, 152 correspond to the corresponding ones. It is possible to cut off the supply of hydraulic oil to the two hydraulic actuators M, or to regulate the outflow of hydraulic oil from the two hydraulic actuators M to suppress the occurrence of unintended operation of the robot arm 2. can.

FIG. 4 is a block diagram showing a control unit of the first and second linear solenoid valves 151 and 152 in the above-mentioned control device 100. As shown in the figure, the control device 100 is a target position setting unit constructed by at least one of hardware such as a CPU, ROM, and RAM of a computer and software such as a control program installed in the computer. 101, current position derivation unit 102, target torque setting unit 105 including torque calculation unit 103 and gravity compensation unit 104, target rigidity setting unit 106, contraction rate setting unit 107, contraction force calculation unit 108, and target pressure derivation. A target pressure setting unit 110 including a unit 109, a current command value setting unit 111, and a valve drive unit 112 are included.

The target position setting unit 101 is a target that is the final target position of the hand unit 4 based on the position of the gripping target of the hand unit 4 and the target speed and target acceleration of the hand unit 4 during movement given by the user. The arrival position (three-dimensional coordinates) and the trajectory from the initial position of the hand unit 4 to the target arrival position and including a plurality of target positions, that is, transit positions (three-dimensional coordinates) are set. The current position derivation unit 102 is a hand unit 4 based on the joint angles θ1, θ2, θ3 of the joints J1-J3 of the robot arm 2 and the specifications (dimensions, etc. of the arm 3) of the robot arm 2 (robot device 1). The current position (three-dimensional coordinates) of (predetermined reference point) is derived. The joint angles θ1-θ3 of the joints J1-J3 are detected by any of the corresponding joint angle sensors 7 provided on the robot arm 2. Hereinafter, “i” is used as a joint number (however, in this embodiment, i = 1, 2, 3), the i-th joint is referred to as “joint Ji”, and the joint angle of joint Ji is “θi”. ".

The torque calculation unit 103 of the target torque setting unit 105 has two arms 3 (arm 3 and a support) connected via the joint Ji so that the hand unit 4 moves from the current position to the target position for each joint J1-J3. The joint torque Tj (i) that relatively rotates the member 5) is calculated. The gravity compensating unit 104 of the target torque setting unit 105 determines the robot arm 2 for each joint J1-J3 based on the joint angle θ1-θ3 and the specifications of the robot arm 2 (robot device 1) (dimensions of the arm 3, etc.). The gravity compensation torque Tc (i) required to maintain the posture of is calculated. Then, the target torque setting unit 105 is for relatively rotating the sum of the joint torque Tj (i) and the gravity compensation torque Tc (i) so that the two arms 3 and the like connected via the joint Ji are relatively rotated. The target torque Ttag (i), which is the target value (target driving force) of the joint torque Tj (i), is set. The target rigidity setting unit 106 has the rigidity that the joint Ji should have for each joint J1-J3, that is, two arms 3 connected via the joint Ji, etc., at least based on the target position of the robot device 1, that is, the hand unit 4. It is a force (torque) required to rotate (link) relatively by a unit angle, and makes it difficult for the joint Ji to move with respect to an external force that tries to relatively rotate the two arms 3 and the like. The indicated target stiffness R (i) is set.

The contraction rate setting unit 107 of the target pressure setting unit 110 is the first artificial artificial muscle corresponding to the joint Ji based on the joint angle θi of the joint Ji according to the current position of the hand unit 4 for each joint J1-J3. The contraction rate Cr1 (i) of the two hydraulic actuators M constituting the muscle AM1 and the contraction rate Cr2 (i) of the two hydraulic actuators M constituting the second artificial muscle AM2 corresponding to the joint Ji are obtained. Set. The shrinkage rates Cr1 (i) and Cr2 (i) indicate the ratio of the axial length of the contracted tube T to the natural length of the tube T of the corresponding hydraulic actuator M in the axial direction, respectively, and the shrinkage rate = (1-at the time of contraction). (Axial length of tube T / natural length of tube T) × 100.

The contraction force calculation unit 108 of the target pressure setting unit 110 has a target torque Ttag (i) set by the target torque setting unit 105 and a target rigidity R (target rigidity R) set by the target rigidity setting unit 106 for each joint J1-J3. Based on i), a plurality of (pair) hydraulic actuators corresponding to the joint Ji when the two arms 3 and the like connected via the joint Ji are relatively rotated by the target torque Ttag (i). The contraction forces Fc1 (i) and Fc2 (i) required for M are calculated. The contraction force Fc1 (i) is a force to be generated by the contraction of the tubes T of the two hydraulic actuators M constituting the first artificial muscle AM1 corresponding to each joint Ji, and the contraction force Fc2 (i) is It is a force to be generated by the contraction of the tube T of the two hydraulic actuators M constituting the second artificial muscle AM2 corresponding to each joint Ji.

The target pressure derivation unit 109 of the target pressure setting unit 110 has the contraction rate Cr1 (i) and the contraction force set by the contraction rate setting unit 107 from the static characteristics of the hydraulic actuator M as an artificial muscle for each joint J1-J3. The pressure corresponding to the contraction force Fc1 (i) calculated by the calculation unit 108 is derived and set to the target pressure Ptag1 (i) of the two hydraulic actuators M constituting the first artificial muscle AM1. Further, the target pressure derivation unit 109 has a contraction rate Cr2 (i) set by the contraction rate setting unit 107 and a contraction force Fc2 (i) calculated by the contraction force calculation unit 108 from the static characteristics for each joint J1-J3. ) And the target pressure Ptag2 (i) of the two hydraulic actuators M constituting the second artificial muscle AM2 by deriving the pressure corresponding to the above.

The current command value setting unit 111 sets the target pressures Ptag1 (i) and Ptag2 (i) set by the target pressure setting unit 110 to the solenoid units 15e of the first and second linear solenoid valves 151 and 152 (current command value setting unit 111). Convert directly to the target current). The valve drive unit 112 sets a target voltage by feed-forward control (or feed-forward control and feedback control) so that the current detected by the above-mentioned current detection unit (not shown) matches the current command value, and sets the target voltage. Convert to PWM signal. Further, the valve drive unit 112 controls switching of a switching element (transistor) (not shown) based on the PWM signal to apply a current to the solenoid units 15e of the first and second linear solenoid valves 151 and 152. As a result, the first and second linear solenoid valves 151 and 152 are controlled to generate hydraulic pressure according to the target pressure Ptag1 (i) or Ptag2 (i).

Subsequently, the control procedure of the above-mentioned robot device 1 will be described with reference to FIGS. 5 to 10. Hereinafter, the control procedure of the robot device 1 will be described by taking as an example a case where the hand portion 4 of the robot device 1 is moved to the gripping target and the hand portion 4 grips and transfers the gripping target.

In the present embodiment, in the control device 100 of the robot device 1, the hand of the robot arm 2, that is, the hand portion 4, and the gripping target are connected via a virtual spring and a damper, and the virtual spring and the damper are generated. It is designed on the assumption that the hand portion 4 is pulled from the current position to the gripping target or the transfer destination of the gripping target by the tensile force Ft. Under this assumption, the tensile force Ft = (f _x , f _y , f _z ) due to the virtual spring and damper is the target position (xd (t), of the hand portion 4 (predetermined reference point). From yd (t), zd (t)) and the current position (x (t), y (t), z (t)) of the hand unit 4, the following is a relational expression of so-called PD control (feedback control). As the sum of the proportional term obtained by multiplying the difference between the target position and the current position by the gain K _px , K _py or K _pz and the velocity term including the gain K _vx , K _vy or K _vz as shown in equation (1). Can be represented.

Further, since the speed of the hand with respect to the gripping target becomes zero when the hand portion 4 is in contact with the gripping target, the gripping target is pulled by the virtual spring and damper according to the above equation (1). The pressing force Fp applied to the gripping target after the contact with the gripping target can be obtained from the target position after the contact and the position of the gripping target (contact position between the hand portion 4 and the gripping target). Therefore, the final target arrival position (x _r , y _r , z _r ) of the hand portion 4 is the pressing force Fp = (f _px , f _py , f _pz ) applied from the hand portion 4 to the gripping object after the contact. , The position (contact position) of the gripping object (x _o , _yo , z _o ) and the gains K _px , K _py , K _pz can be expressed as the following equation (2).

Then, in the robot device 1, prior to the start of operation of the robot arm 2 (before the start of movement of the hand unit 4), the routine of FIG. 5 is executed by the target position setting unit 101 of the control device 100, and the final of the hand unit 4 is executed. A target arrival position (x _r , y _r , z _r ) and a target trajectory of the hand unit 4 from the initial position to the target arrival position (x _r , y _r , z _r ) are set. At the start of the routine of FIG. 5, the target position setting unit 101 of the control device 100 determines the position (x _o , _yo , z _o ) of the gripping target and the target speed of the hand unit 4 given by the user during movement. And the target acceleration is acquired (step S1). The position (x _o , _yo , z _o ) of the gripping object may be input to the control device 100 by the user of the robot device 1 if it is known in advance, and the camera may be input to the control device 100 before the operation of the robot arm 2 is started. It may be derived from the data acquired by the above.

Next, the target position setting unit 101 reaches the target of the hand unit 4 in which a predetermined pressing force Fp is applied from the hand unit 4 to the gripping object after the contact between the hand unit 4 and the gripping object according to the above equation (2). The position (x _r , y _r , z _r ) is set (step S2). In the robot device 1, the pressing force Fp = (f _px , f _py , f _pz ) in the equation (2) is based on the specifications such as the material, strength, and size of the gripping object, without destroying the gripping object. Is predetermined in consideration of variations in the positions (x _o , _yo , z _o ) of the gripping target so as to bring the gripping target into contact with the gripping target. Further, the target position setting unit 101 is based on the target speed and target acceleration of the hand unit 4 acquired in step S1 and the target arrival position (x _r , y _r , z _r ) set in step S2. A target trajectory of the hand unit 4 including a predetermined number (plural) target positions, that is, transit positions (three-dimensional coordinates) is set (step S3), and the routine of FIG. 5 is terminated.

Further, in the robot device 1, after the target arrival position and the target trajectory are set according to the position of the grip target, the target arrival position and the target trajectory are set according to the transfer destination (the mounting surface of the grip target) of the grip target. In order to do so, the routine of FIG. 5 is executed again by the target position setting unit 101. At this time, the target position setting unit 101 is placed on the mounting surface (target) from the hand unit 4 via the gripping target after the contact between the gripping target (hand) gripped by the hand unit 4 and the mounting surface (target). The target arrival position (x _r , y _r , z _r ) of the hand unit 4 to which the predetermined pressing force Fp is applied is set.

FIG. 6 is a flowchart illustrating a robot arm control routine executed by the control device 100 after the target arrival position and the target trajectory are set. After the routine of FIG. 5 is completed, the routine of FIG. 6 is repeatedly executed by the control device 100 at predetermined time (for example, about 10 ms) in response to an execution instruction by the user.

At the start of the routine of FIG. 6, the torque calculation unit 103 (target torque setting unit 105) and the target rigidity setting unit 106 of the control device 100 each acquire the target position set by the target position setting unit 101 (step S10). .. The target position acquired in step S10 is the first target position in the target trajectory or the target position acquired at the time of the previous execution of the routine of FIG. Further, the current position derivation unit 102 and the gravity compensation unit 104 of the control device 100 acquire the joint angles θ1-θ3 of the joints J1-J3 acquired by the plurality of joint angle sensors 7 (step S20). The current position deriving unit 102 derives the current position (three-dimensional coordinates) of the hand unit 4 based on the acquired joint angle θ1-θ3 and the specifications of the robot arm 2 (robot device 1) (step S30). The derived current position is given to the torque calculation unit 103.

The torque calculation unit 103 (target torque setting unit 105) of the control device 100 determines whether or not the current position of the hand unit 4 has changed from the previous position (whether or not the hand unit 4 has moved) (step). S40). When the torque calculation unit 103 determines that the current position of the hand unit 4 has changed from the previous position (step S40: YES), it further determines whether or not the current position substantially matches the target position. Determination (step S50). When it is determined that the current position substantially matches the target position (step S50: YES), the torque calculation unit 103 acquires the target position next to the target position acquired in step S10 (step S60). .. The next target position is also given to the target rigidity setting unit 106, and the target rigidity setting unit 106 sets the target rigidity R (i) of each joint Ji based on the acquired target position and the like. Further, if the current position of the hand unit 4 does not substantially match the target position, the process of step S60 is skipped.

After the process of step S50 or S60, the target torque setting unit 105 of the control device 100 sets the target torque Ttag (i) for each joint Ji (step S70). FIG. 7 is a flowchart illustrating a procedure for setting the target torque Ttag (i) by the target torque setting unit 105 in step S70. As shown in the figure, the torque calculation unit 103 of the target torque setting unit 105 first sets the above-mentioned gains K _px , K _py and K _pz based on the target position of the hand unit 4 acquired in step S10. (Step S700). In step S700, the torque calculation unit 103 has gains K _px , K _py and K _pz until the target position acquired in step S10 reaches a predetermined target position (for example, a position where the hand unit 4 starts decelerating). After each is set to a predetermined normal value and the target position acquired in step S10 becomes the predetermined target position, each of the gains K _px , K _py and K _pz is smaller than the above normal value. Set to a value.

Next, the torque calculation unit 103 describes the above-mentioned virtual from the above equation (1) based on the target position of the hand unit 4 acquired in step S10 and the current position of the hand unit 4 acquired in step S30. The tensile force Ft = (f _x , f _y , f _z ) due to the spring and the damper is calculated (step S710). In step S710, the tensile force Ft = (f _x , f _y , f _z ) may be calculated from the following equation (3), or the equations (1) and (3) may be used in combination. By using the equation (3), the movement of the robot arm 2 (each joint Ji) can be made smoother.

Further, the torque calculation unit 103 acquires a separately set human feeling flag (step S720), and determines whether or not the human feeling flag is turned off (step S730). The human sensor is turned on or off by the control device 100 based on a signal from at least one motion sensor 8 (see FIG. 1) arranged at the installation location of the robot device 1 or an automatic guided vehicle. .. That is, when the presence of a person is not detected by the at least one motion sensor 8, the control device 100 turns off the human sensor, and when the presence of a person is detected by at least one motion sensor 8, the control device 100 turns off the human sensor. Turn on the motion flag.

When the torque calculation unit 103 determines that the human feeling flag is turned off (step S730: YES), the torque calculation unit 103 sets the first force (vector) Fu1 to the upper limit value Fu of the tensile force Ft (step S740). Further, when the torque calculation unit 103 determines that the human feeling flag is turned on (step S730: NO), the torque calculation unit 103 sets the second force (vector) Fu2, which is smaller than the first force Fu1, to the upper limit of the tensile force Ft. Set to the value Fu (step S745). After the process of step S740 or S745, the torque calculation unit 103 sets (resets) the smaller of the tensile force Ft and the upper limit value Fu set in step S710 to the tensile force Ft (step S750).

Further, as shown in the following equation (4), the torque calculation unit 103 has a hand unit 4 for each joint J1-J3 from the tensile force Ft set in step S750 and the Jacobian determinant shown in the following equation (5). Calculates the joint torque Tj (i) that relatively rotates the two arms 3 (arm 3 and support member 5) connected via the joint Ji so that the force moves from the current position to the target position (step S760). ). Then, the target torque setting unit 105 sums the joint torque Tj (i) calculated by the torque calculation unit 103 as described above and the gravity compensation torque Tc (i) separately calculated by the gravity compensation unit 104. The target torque Ttag (1) -Ttag (3) for relatively rotating the two arms 3 and the like is set (step S770).

When the target torque Ttag (i) for each joint Ji is set in step S70 (step S770), the target pressure setting unit 110 of the control device 100 uses the joint Ji, that is, the plurality of hydraulic actuators M for each arm 3. The target pressures Ptag1 (i) and Ptag2 (i) are set (step S80). FIG. 8 is a flowchart illustrating the setting procedure of the target pressures Ptag1 (i) and Ptag2 (i) by the target pressure setting unit 110 in step S80. As shown in the figure, the target pressure setting unit 110 first sets the variable i, that is, the joint number to the value 1 (step S800). Next, the contraction force calculation unit 108 of the target pressure setting unit 110 has a target torque Ttag (i) for the joint Ji set by the target torque setting unit 105 and a target rigidity of the joint Ji set by the target rigidity setting unit 106. Acquire R (i) (step S810). Further, in step S810, the contraction rate setting unit 107 of the target pressure setting unit 110 acquires the current joint angle θi of the joint Ji detected by the corresponding joint angle sensor 7.

The contraction rate setting unit 107 of the target pressure setting unit 110 that has acquired the joint angle θi has the contraction rate Cr1 (i) of the two hydraulic actuators M constituting the first artificial muscle AM1 corresponding to the joint Ji, and the joint. The contraction rate Cr2 (i) of the two hydraulic actuators M constituting the second artificial muscle AM2 corresponding to Ji is set (step S820). In step S820, the contraction rate setting unit 107 configures the first artificial muscle AM1 based on the joint angle θi of the joint Ji, the specifications of the robot arm 2 (robot device 1) (dimensions of the arm 3 and the like), and the like. The contraction rate Cr1 (i) of the two hydraulic actuators M and the contraction rate Cr2 (i) of the two hydraulic actuators M constituting the second artificial muscle AM2 are derived and set.

Further, the contraction force calculation unit 108 of the target pressure setting unit 110 is the first artificial muscle corresponding to the joint Ji based on the target torque Ttag (i) acquired in step S810 and the target rigidity R (i) of the joint Ji. The contraction force (tensile force) Fc1 (i) required for the two hydraulic actuators M constituting the muscle AM1 and the two hydraulic actuators M constituting the second artificial muscle AM2 corresponding to the joint Ji are required. The contraction force (tensile force) Fc2 (i) to be generated is calculated (step S830). Here, the relationship between the target torque Ttag (i) and the contractile forces Fc1 (i) and Fc2 (i) | Ttag (i) | = | r (Fc1 (i) -Fc2 (i)) | (However, "r" is a conversion coefficient). Further, it can be considered that the relationship of R (i) = Fc1 (i) + Fc2 (i) is established between the target rigidity R (i) of the joint Ji and the contractile forces Fc1 (i) and Fc2 (i). can. Therefore, in step S830, the contraction force calculation unit 108 solves the simultaneous equations obtained from these two relational expressions, and thereby, the contraction force Fc1 corresponding to the target torque Ttag (i) and the target rigidity R (i) of the joint Ji. (I), Fc2 (i) is calculated.

After the processing of steps S820 and S830, the target pressure derivation unit 109 of the target pressure setting unit 110 has a pressure corresponding to the contraction rate Cr1 (i) and the contraction force Fc1 (i) from the target pressure setting map illustrated in FIG. Is appropriately linearly interpolated and set to the target pressure Ptag1 (i) of the two hydraulic actuators M constituting the first artificial muscle AM1 (step S840). Further, in step S840, the target pressure derivation unit 109 derives the pressure corresponding to the contraction rate Cr2 (i) and the contraction force Fc2 (i) from the target pressure setting map to form the second artificial muscle AM2. The target pressure Ptag2 (i) of the two hydraulic actuators M is set.

The target pressure setting map of FIG. 9 shows the static characteristics of the hydraulic actuator M as an artificial muscle, and the contraction rate of the tube T and the tube T are generated for each hydraulic pressure supplied to the hydraulic actuator M. It was created through experiments and analysis in advance so as to define the relationship with the contractile force. In this way, the pressure corresponding to the contraction rates Cr1 (i) and Cr2 (i) and the contraction forces Fc1 (i) and Fc2 (i) of the tube T is set to the target pressures Ptag1 (i) and Ptag2 (i). Therefore, the target pressures Ptag1 (i) and Ptag2 (i) can be set accurately according to the request to the robot arm 2.

When the target pressures Ptag1 (i) and Ptag2 (i) are set in step S840, the target pressure setting unit 110 increments the variable i (step S850) and determines whether or not the variable i is a value N + 1 or more. Determination (step S860). The value N indicates the number of joints in the robot arm 2, and in this embodiment, N = 3. When the target pressure setting unit 110 determines that the variable i is less than the value N + 1 (step S860: NO), the target pressure setting unit 110 re-executes the process of the above steps S810-S860. When the target pressure setting unit 110 determines that the variable i is the value N + 1 or more (step S860: YES), as shown in FIG. 6, the current command value setting unit 111 of the control device 100 displays a map or the like (not shown). Using, each of the target pressures Ptag1 (i) and Ptag2 (i) of each joint Ji is directly converted into a current command value (step S90). The current command value derived by the current command value setting unit 111 is given to the valve drive unit 112 of the control device 100, and the valve drive unit 112 has a plurality of first and second linear solenoids, respectively, based on the current command. The valves 151 and 152 are controlled (PWM control) (step S100).

As a result, the current command value to the liquid supply device 10 according to the target torque Ttag (i) is easily and quickly set, and the first and second linears of the liquid supply device 10 are controlled based on the current command value. Each of the solenoid valves 151 and 152 produces a hydraulic pressure corresponding to the corresponding target pressure Ptag1 (i) or Ptag2 (i). Further, the hydraulic oil regulated by the first and second linear solenoid valves 151 and 152 is supplied to the tube T of the corresponding hydraulic actuator M via the first and second supply cutoff valves 161, 162. As a result, the flow rate control valve adjusts the flow rate of the hydraulic oil and supplies it into the tube T, or the hydraulic pressure supplied to the tube T is detected by the pressure sensor so that the actual hydraulic pressure matches the target pressure. The hydraulic pressure supplied to each tube T within a short time from the setting of the target pressures Ptag1 (i) and Ptag2 (i) is applied to the target pressures Ptag1 (i) and Ptag2 (i), as compared with the case of feedback control. It is possible to substantially match i) so that the actual shrinkage rate of each tube T can be made to follow the required value with good responsiveness and high accuracy. After the process of step S100, the control device 100 temporarily terminates the routine of FIG. 6, and executes the process of step S10 and subsequent steps again according to the arrival of the next execution timing.

On the other hand, when it is determined in step S40 of FIG. 6 that the current position of the hand unit 4 has not substantially changed from the previous position (step S40: NO), the torque calculation unit 103 determines that the current position is from the previous position. It is determined whether or not a predetermined relatively short time (predetermined time) has elapsed since the change substantially stopped (step S55). When it is determined that the predetermined time has not elapsed since the current position does not substantially change (step S55: NO), the torque calculation unit 103 determines, for example, the difference between the target arrival position and the current position and the said. The target position of the hand unit 4 is set based on the predetermined time (step S65). In step S65, for example, the torque calculation unit 103 sets the target position so that the target position coincides with the target arrival position shortly before the predetermined time elapses after the current position does not substantially change. And change at a constant rate. After the process of step S65, the processes after step S70 are executed. Further, the target position set in step S65 is also given to the target rigidity setting unit 106, and the target rigidity setting unit 106 sets the target rigidity R (i) of each joint Ji based on the acquired target position and the like. Set. As a result, after the contact between the hand portion 4 and the gripping target (or after the contact between the gripping target and the mounting surface), a force equal to or less than the pressing force Fp is applied from the hand portion 4 to the gripping target (or the mounting surface). Will be added.

When it is determined in step S55 that the predetermined time has elapsed since the current position does not substantially change, the control device 100 ends the routine of FIG. 6 and causes the hand unit 4 to grip the gripping object. Executes the hand control routine of. Further, the target position setting unit 101 of the control device 100 executes the routine of FIG. 5 until the gripping target is gripped by the hand unit 4, and sets the target arrival position and the target trajectory according to the mounting position of the gripping target. Set. Further, when the gripping target is gripped by the hand unit 4 and the hand control routine is completed, the control device 100 re-executes the routine of FIG. 6 in order to convey the gripping target to the mounting position by the robot arm 2. After the negative determination is made in step S40, the target position of the hand unit 4 may be set to change at a predetermined rate from the current position to the target arrival position, and the target position is one to the target arrival position. The routine of FIG. 6 may be terminated when a predetermined time has elapsed.

As described above, the target position setting unit 101 of the control device 100 of the robot device 1 mounts the gripping target (hand) gripped by the hand portion 4 of the robot device 1 or the hand portion 4 on the gripping target or the gripping target. When contacting the mounting surface (object), after the contact between the hand unit 4 and the gripping object or after the contact between the gripping object and the mounting surface (after time t2 in FIG. 10), the gripping object or mounting from the hand unit 4 A target reaching position of the hand portion 4 to which a predetermined pressing force Fp is applied to the surface is set (step S2 in FIG. 5). That is, as shown in FIG. 10, the target position setting unit 101 sets a position slightly ahead of the position of the pinching target or the like to the target arrival position of the hand unit 4. Further, the control device 100 has a target torque Ttag (i) for each joint Ji of the robot arm 2 based on the target position included in the target trajectory set based on the target arrival position and the current position of the hand unit 4. (Step S70 in FIG. 6), and the target pressures Ptag1 (i) and Ptag2 (i) of the plurality of hydraulic actuators M corresponding to each joint Ji are set based on the target torque Ttag (i) (FIG. 6). Step S80 of 6. Further, the control device 100 controls the first and second linear solenoid valves 151 and 152 of the liquid supply device 10 based on the target pressures Ptag1 (i) and Ptag2 (i) (steps S90-S100 in FIG. 6).

As a result, for example, the above-mentioned pushing is performed in consideration of variations in the position of the gripping object or the like so that the hand portion 4 or the gripping object (hand) is brought into contact with the gripping object or the mounting surface (object) without destroying the gripping object. If the pressure Fp is set, the moving speed of the hand unit 4 is reduced when the hand unit 4 or the like approaches the gripping object to some extent, or the sensor detects the contact between the hand unit 4 or the like and the gripping object or the like. It is possible to bring the hand portion 4 or the like of the robot device 1 into contact with the gripping object or the like without causing the trouble. Further, the target torque (target driving force) Ttag (i) based on the target position and the current position of the hand unit 4, more specifically, the target pressures Ptag1 (i) and Ptag2 (i) based on the target torque Ttag (i). By controlling the liquid supply device 10 based on the above, each hydraulic actuator M can be responsively and highly responsive to a request without using a sensor for detecting the hydraulic pressure supplied to each hydraulic actuator M as an artificial muscle. It is possible to operate with high accuracy.

Further, the target position setting unit (target arrival position setting unit and target trajectory setting unit) 101 of the control device 100 sets the target arrival position, and is based on the target arrival position, the target speed of the hand unit 4, and the target acceleration. The target trajectory of the hand unit 4 including the plurality of target positions is set (steps S1-S3 in FIG. 5). Further, the target torque setting unit 105 calculates the tensile force (driving force) Ft for moving the hand unit (hand) 4 of the robot device 1 from the current position to the target position, and determines the joint Ji based on the tensile force Ft. The target torque Ttag (i) for relatively rotating the two arms (links) 3 and the like connected via the beam is set (step S70 in FIG. 6 and steps S700-S770 in FIG. 7). Further, the target pressure setting unit 110 sets the target pressures Ptag1 (i) and Ptag2 (i) based on the target torque Ttag (i) (step S80 in FIG. 6). Further, the current command value setting unit 111 directly converts the target pressures Ptag1 (i) and Ptag2 (i) into current command values to the first and second linear solenoid valves 151 and 152 of the liquid supply device 10 (FIG. 6). Step S90).

As a result, the current command values from the target torque Ttag (i) to the first and second linear solenoid valves 151 and 152 are easily and quickly set to respond to the hydraulic pressure supplied to each hydraulic actuator M as an artificial muscle. While controlling well, the hand portion 4 of the robot device 1 is moved so as to follow a target trajectory by a plurality of hydraulic actuators M so that the hand portion 4 is brought into contact with the gripping target, or the gripping target is brought into contact with the mounting surface. It is possible to make it. The target position setting unit 101 may set only the target arrival position without setting the target trajectory. In this case, the target torque setting unit 105 determines the difference between the target arrival position and the current position. The target Ttag (i) may be set based on the above. Further, when the position of the gripping object cannot be accurately acquired at the start of starting the robot device 1, the position of the gripping object acquired by a camera or the like at predetermined time intervals after the hand unit 4 approaches the gripping object. The target arrival position may be derived from the predetermined time intervals.

Further, the torque calculation unit 103 of the target torque setting unit 105 calculates the tensile force Ft so as not to exceed a predetermined upper limit value Fu (Fu1 or Fu2) (step S750 in FIG. 7). In addition, as shown in FIG. 10, the torque calculation unit 103 has a person around the robot device 1 (for example, an area including an operating range of the robot arm 2 such as a room where the robot device 1 is arranged or the inside of a fence). When this is detected and the human feeling flag is turned on (see time t1 in FIG. 10 and the two-dot chain line in the figure), the upper limit value Fu is made smaller than when there is no person around the robot device 1 (FIG. 7). Step S720-S745). As a result, even if a person comes into contact with the robot device 1 while the hand portion 4 of the robot device 1 moves along the target trajectory, the force that the person receives after the contact can be satisfactorily relaxed.

Further, in the control device 100 of the robot device 1, the target position setting unit (target trajectory setting unit) 101 limits the separately given target acceleration so as not to exceed a predetermined upper limit acceleration, and the hand unit at predetermined time intervals. It may set the target position of 4. In this case, the target position setting unit 101 may be configured so that when there is a person around the robot device 1, the upper limit acceleration is smaller than when there is no person around the robot device 1. Even with this aspect, even if a person comes into contact with the robot device 1 while the hand portion 4 of the robot device 1 moves along the target trajectory, the force received by the person after the contact can be satisfactorily relaxed. Become.

Further, in the above embodiment, the torque calculation unit 103 of the target torque setting unit 105 includes a relational expression of feedback control including a proportional term obtained by multiplying the difference between the target position and the current position by the gains K _px , K _py , and K _pz . The tensile force Ft is calculated according to 1), and the gains K _px , K _py , and K _pz are changed according to the target position of the hand portion 4 (step S700 in FIG. 7). This makes it possible to change the followability of the hand unit 4 to the target trajectory and the degree of increase of the pressing force Fp applied from the hand unit 4 or the like to the gripping object or the like after contact.

That is, when the gains K _px , K _py , and K _pz are increased, the followability of the hand portion 4 to the target trajectory is improved, while after the contact between the hand portion 4 and the gripping target or between the gripping target and the mounting surface. The increasing gradient of the pressing force Fp after the contact is increased. On the other hand, when the gains K _px , K _py , and K _pz are reduced, the followability of the hand portion 4 to the target trajectory becomes gentle, but after the contact between the hand portion 4 and the gripping target or on the gripping target. The increasing gradient of the pressing force Fp after contact with the mounting surface can be reduced. Therefore, as described above, if the gains K _px , K _py , and K _pz are made smaller than the previous values when the hand portion 4 approaches the gripping object or the mounting surface to some extent, the responsiveness of the robot device 1 is achieved. And safety can be further improved. In step S700 of FIG. 7, the gains K _px , K _py , and K _pz may be changed according to the current position of the hand unit 4.

Further, in the above embodiment, the torque calculation unit 103 of the target torque setting unit 105 calculates the joint torque Tj (i) for moving the hand unit 4 of the robot device 1 from the current position to the target position for each joint J1-J3. do. Further, the gravity compensating unit 104 of the target torque setting unit 105 calculates the gravity compensating torque Tc (i) required to maintain the posture of the robot arm 2 (robot device 1) for each of the joints J1-J3. Further, the target torque setting unit 105 is for relatively rotating the sum of the joint torque Tj (i) and the gravity compensating torque Tc (i) to rotate the two arms 3 and the like connected via the joint Ji. The target torque Ttag (i) is set (step S70 in FIG. 6 and step S770 in FIG. 7). This makes it possible to move the hand portion 4 of the robot device 1 by the plurality of hydraulic actuators M while suppressing the disturbance of the behavior of the robot arm 2 (robot device 1).

Further, the control device 100 corresponds to the target rigidity setting unit 106 that sets the target rigidity R (i) of each joint Ji based on at least the target position of the hand unit 4 of the robot device 1 and the current position of the robot device 1. Based on the contraction rate setting unit 107 that sets the contraction rates Cr1 (i) and Cr2 (i) of each hydraulic actuator M based on each joint angle θi, and the target torque Ttag (i) and the target rigidity R (i). The contraction force calculation unit 108 that calculates the contraction forces Fc1 (i) and Fc2 (i) required for the plurality of (pair) hydraulic actuators M corresponding to the joint Ji, and the contraction rate Cr1 (i) from the target pressure setting map. ) And the pressure corresponding to the contraction force Fc1 (i) and the contraction rate Cr2 (i) and the pressure corresponding to the contraction force Fc2 (i) are derived and set to the target pressures Ptag1 (i) and Ptag2 (i). Includes a target pressure derivation unit 109. As a result, the target pressures Ptag1 (i) and Ptag2 (i) are set accurately according to the requirements of each hydraulic actuator M as an artificial muscle, and the robot device 1 including the plurality of hydraulic actuators M is responsively stable. It becomes possible to operate.

Subsequently, with reference to FIGS. 11 and 12, the procedure for setting the target rigidity R (i) by the target rigidity setting unit 106 of the control device 100 will be described.

11 and 12 are flowcharts illustrating a target rigidity setting routine executed by the target rigidity setting unit 106 of the control device 100. The target rigidity setting routine shown in these drawings is repeatedly executed by the target rigidity setting unit 106 at predetermined time intervals (for example, about 10 ms) in parallel with the robot arm control routine of FIG.

At the start of the target rigidity setting routine, the target rigidity setting unit 106 uses the target arrival position of the hand unit 4, the target position of the hand unit 4 used in the robot arm control routine of FIG. 6 at that time, and the above-mentioned person. Acquire the feeling flag (step S600). Next, the target rigidity setting unit 106 determines whether or not the human feeling flag is turned off (step S605), and when it is determined that the human feeling flag is turned off (step S605: YES), the hand unit 4 determines. It is determined whether or not the gripping object is gripped (step S610). When it is determined that the gripping target is not gripped by the hand unit 4 (step S610: NO), the target rigidity setting unit 106 is concerned based on the target arrival position and the target position of the hand unit 4 acquired in step S600. It is determined whether or not the hand portion 4 is located substantially directly above the gripping target (step S615).

When the target rigidity setting unit 106 determines that the hand unit 4 is not located substantially directly above the gripping object (step S615: NO), the target rigidity value Rm is predetermined for each of the joints J1-J3. (I) is set to the target rigidity R (i) of each joint Ji (step S620), and the target rigidity setting routine is temporarily terminated. The rigidity value Rm (i) may be set so as to be able to suppress the vibration of the robot arm 2 while ensuring the contraction force (torque) of each hydraulic actuator M. Further, when it is determined that the hand portion 4 is located substantially directly above the gripping target (step S615: YES), the target rigidity setting unit 106 has a relatively low rigidity predetermined for each of the joints J1-J3. The value Rl (i) is set to the target stiffness R (i) of each joint Ji (step S640), and the target stiffness setting routine is temporarily terminated.

Here, the maximum contractile force generated by the two hydraulic actuators M constituting the first artificial muscle AM1 corresponding to the joint Ji and the two hydraulic pressures constituting the second artificial muscle AM2 corresponding to the joint Ji. If the maximum contraction force generated by the actuator M is the same and the maximum contraction force is "Fmax", the maximum torque Tmax that can be applied to the joint Ji from the four hydraulic actuators M is | Tmax | = | r. (Fc1 (i) -Fc2 (i)) | = | r · Fmax | At this time, the rigidity R of the joint Ji is R = Fmax. Therefore, in the present embodiment, the rigidity value Rl (i) is Fmax ≦ Rl (1) <Rm (1), Fmax ≦ Rl (2) <in order to enable output of the maximum torque Tmax = r · Fmax. It is predetermined to satisfy Rm (2) and Fmax ≦ Rl (3) <Rm (3). As a result, when the hand portion 4 is lowered (approached) toward the object, the hand portion 4 (a part of the robot arm 2) is provided while sufficiently securing the contraction force (torque) of each hydraulic actuator M. The impact when contacting the gripping object can be well absorbed by the joints J1-J3.

Further, when the target rigidity setting unit 106 determines that the gripping target is gripped by the hand unit 4 (step S610: YES), the target rigidity setting unit 106 is based on the target arrival position and the target position of the hand unit 4 acquired in step S600. , It is determined whether or not the hand portion 4 is located substantially directly above the mounting position of the gripping target (step S625). When it is determined that the hand unit 4 is located substantially directly above the mounting position (step S625: YES), the target rigidity setting unit 106 concerned, for example, based on the target arrival position and the target position of the hand unit 4. It is determined whether or not the hand portion 4 is moving toward the mounting position (step S630).

When the target rigidity setting unit 106 determines that the hand unit 4 is moving toward the mounting position (step S630: YES), for example, the hand unit is based on the target arrival position and the target position of the hand unit 4. It is determined whether or not 4 has reached a position separated from the mounting position by a relatively short predetermined distance (step S635). When it is determined that the hand unit 4 has reached a position separated by a predetermined distance from the mounting position (step S635: YES), the target rigidity setting unit 106 sets the above-mentioned relatively low rigidity value Rl (i) to each joint. The target rigidity R (i) of Ji is set (step S640), and the target rigidity setting routine is temporarily terminated. This makes it possible for the joints J1-J3 to satisfactorily absorb the impact when the gripping object gripped by the hand portion 4 is placed on the mounting surface.

On the other hand, when it is determined that the hand unit 4 has not reached a position separated by a predetermined distance from the mounting position (step S635: NO), the target rigidity setting unit 106 determines each of the joints J1-J3 in advance. The relatively high rigidity value Rh (i) obtained is set to the target rigidity R (i) of each joint Ji (step S645), and the target rigidity setting routine is temporarily terminated. Further, when it is determined that the hand portion 4 is substantially directly above the mounting position and separated from the mounting position (step S630: NO), the target rigidity setting unit 106 is predetermined for each of the joints J1-J3. The relatively high rigidity value Rh (i) obtained is set to the target rigidity R (i) of each joint Ji (step S645), and the target rigidity setting routine is temporarily terminated. This makes it possible to satisfactorily absorb the vibration of the robot arm 2 when the gripping object gripped by the hand portion 4 is lifted or lowered toward the mounting position.

Here, the contraction force generated by the two hydraulic actuators M constituting the first artificial muscle AM1 corresponding to the joint Ji and the two hydraulic actuators M constituting the second artificial muscle AM2 corresponding to the joint Ji. When both the contraction force generated by the joint Ji and the contraction force are the maximum contraction force Fmax, the maximum value of the rigidity Rmax of the joint Ji is Rmax = 2 × Fmax. Therefore, in the present embodiment, the rigidity values Rh (i) are Rm (1) <Rh (1) ≦ 2 × Fmax, Rm (2) <Rh (2) ≦ 2 × Fmax, and Rm (3) <. It is predetermined to satisfy Rh (3) ≦ 2 × Fmax.

On the other hand, when it is determined that the hand unit 4 is not located substantially directly above the mounting position (step S625: NO), the target rigidity setting unit 106 is the hand unit 4 at that time as shown in FIG. The target acceleration of (step S650) is acquired, and it is determined whether or not the hand unit 4 accelerates or decelerates based on the target acceleration (step S660). When it is determined that the hand unit 4 moves at a constant speed (step S660: NO), the target rigidity setting unit 106 sets the above-mentioned medium rigidity value Rm (i) to the target rigidity R (i) of each joint Ji. (Step S675), the target rigidity setting routine is temporarily terminated.

Further, when the target rigidity setting unit 106 determines that the hand unit 4 accelerates or decelerates (step S660: YES), the target rigidity setting unit 106 further determines whether or not the hand unit 4 accelerates from the target acceleration acquired in step S650. (Step S670). When it is determined that the hand unit 4 accelerates (step S670: YES), the target rigidity setting unit 106 sets the above-mentioned relatively low rigidity value Rl (i) to the target rigidity R (i) of each joint Ji (step). S680), the target rigidity setting routine is temporarily terminated. As a result, when the hand portion 4 that grips the gripping object accelerates, it is possible to sufficiently secure the contraction force (torque) of each hydraulic actuator M. When it is determined that the hand unit 4 decelerates (step S670: NO), the target rigidity setting unit 106 sets the above-mentioned relatively high rigidity value Rh (i) to the target rigidity R (i) of each joint Ji. (Step S690), the target rigidity setting routine is temporarily terminated. This makes it possible to satisfactorily absorb the vibration of the robot arm 2 when the hand portion 4 that grips the gripping object decelerates.

Further, when the target rigidity setting unit 106 determines that the human feeling flag is turned on (step S605: NO), the above-mentioned relatively low rigidity value Rl (i) is set to the target rigidity R (i) of each joint Ji. (Step S640), and the target rigidity setting routine is temporarily terminated. As a result, even if one person comes into contact with the robot arm 2 or the hand portion 4 while the robot device 1 is operating, it is possible to satisfactorily alleviate the impact caused by the contact received by the person.

As described above, the robot device 1 operates by receiving a supply of a plurality of joints Ji and hydraulic oil (liquid), and relatively has two arms (links) 3 and the like connected via the joints Ji. A plurality of hydraulic actuators (artificial muscles) M to be rotated to, a plurality of first linear solenoid valves 151 and a plurality of second linear solenoid valves for adjusting the pressure of hydraulic oil supplied to the plurality of hydraulic actuators M. The 152 includes a control device 100 for controlling the first and second linear solenoid valves 151 and 152. Further, the control device 100 sets a target torque setting unit 105 for setting a target torque Ttag (i) for relatively rotating the two arms 3 and the like, and a target rigidity R (i) for each joint Ji. The target rigidity setting unit 106 is included. Then, the control device 100 determines the hydraulic target pressures Ptag1 (i) and Ptag2 (i), which are supplied to the plurality of hydraulic actuators M corresponding to the joint Ji based on the target torque Ttag (i) and the target rigidity R (i). i) is set, and the first and second linear solenoid valves 151 and 152 are controlled based on the target pressures Ptag1 (i) and Ptag2 (i) (steps S70-S100 in FIG. 6 and steps S800- in FIG. 8). 860).

That is, the force to be output from the hydraulic actuator M as an artificial muscle in order to relatively rotate the two arms 3 and the like relatively rotates the two arms 3 and the like connected via the joint Ji. It can be determined from the target torque Ttag (i) for making the target torque Ttag (i) and the target rigidity R (i) of the joint Ji connecting the two arms 3 and the like. Then, the target hydraulic pressures Ptag1 (i) and Ptag2 (i) to the hydraulic actuator M are set based on the target torque Ttag (i) and the target rigidity R (i), and the target pressures Ptag1 (i), By controlling the first and second linear solenoid valves 151 and 152 based on Ptag2 (i), it is possible to operate each hydraulic actuator M with high responsiveness and high accuracy so as to output a force according to the request. Will be. As a result, the rigidity of the joint Ji can be changed with good responsiveness and high accuracy. Therefore, the rigidity of the joint Ji can be reduced to allow the required torque output, and the operation of the robot device 1 can be stabilized. Therefore, it is possible to increase the rigidity of the joint Ji. As a result, the robot device 1 including the plurality of hydraulic actuators M that relatively rotate the two arms 3 and the like connected via the joint Ji can be stably operated with good responsiveness.

Further, the target rigidity setting unit 106 of the control device 100 determines the target rigidity R (i), which is the rigidity that the joint Ji should have, for each of the joints J1-J3, at least based on the target position of the robot device 1, that is, the hand unit 4. Set. As a result, the target rigidity R (i) of each joint Ji is required to be lowered at a position where a large torque is required to relatively rotate the two arms 3 and the like connected via the joint Ji. The target rigidity R of each joint Ji is to stabilize the operation of the robot device 1 at a position where a large torque is not required to relatively rotate the two arms 3 and the like while allowing the output of the torque. i) can be increased. However, in the robot device 1, the target rigidity R (i) of each joint Ji may be set at least based on the current position of the hand portion 4 (robot device 1).

Further, when the target rigidity setting unit 106 moves the hand unit 4 of the robot device 1 to the gripping target or the mounting position (target) of the gripping target, the target rigidity setting unit 106 responds to the positional relationship between the robot device 1 and the gripping target or the like. The target rigidity R (i) of each joint Ji is changed (step S600-S690). This makes it possible to operate the robot device 1 responsively and stably to move the hand portion 4 toward the gripping target or the like.

Further, the target rigidity setting unit 106 lowers the target rigidity R (i) of each joint Ji before the hand unit 4 which is a part of the robot device 1 comes into contact with the gripping target (steps S615 and S640), and the hand. The target rigidity R (i) of each joint Ji is lowered before the gripping object gripped by the portion 4 and substantially a part of the robot device 1 comes into contact with the mounting surface (steps S635 and S640). As a result, the impact when the hand portion 4 or the like of the robot device 1 comes into contact with the gripping object or the like can be satisfactorily absorbed by each joint Ji.

Further, the target rigidity setting unit 106 changes the target rigidity R (i) of each joint Ji according to the moving speed and acceleration of the hand unit 4 of the robot device 1 (steps S650-S690). As a result, the target rigidity R (i) of each joint Ji is lowered to allow acceleration or high-speed movement of the hand portion 4 of the robot device 1, or when the hand portion 4 of the robot device 1 decelerates or moves at low speed. It is possible to increase the target rigidity R (i) of the joint Ji and suppress the generation of vibration.

Further, the target rigidity setting unit 106 lowers the target rigidity R (i) of each joint Ji when there is a person around the robot device 1 (steps S605 and S640). As a result, even if a person comes into contact with the robot device 1, the impact caused by the contact received by the person can be satisfactorily mitigated.

Further, in the robot device 1, the two arms 3 and the like are arranged so as to antagonize the two hydraulic actuators M constituting the first artificial muscle AM1 and the two hydraulic actuators M. It is relatively rotated by the other two hydraulic actuators M constituting the artificial muscle AM2.

As a result, one of the two arms 3 and the like connected via the joint Ji by a plurality of paired hydraulic actuators M is rotated with respect to the other with good responsiveness and high accuracy, and the rigidity of the joint Ji is increased. Can be satisfactorily approached to the target rigidity R (i). However, it is not always necessary to provide a plurality of paired hydraulic actuators (artificial muscles) M on the two arms 3 and the like connected via the joint Ji, and one or a plurality of the two arms 3 and the like. The hydraulic actuator M of the above may be connected to an elastic body such as a spring or a rubber material arranged so as to antagonize the hydraulic actuator M.

Further, the target pressure setting unit 110 (contraction rate setting unit 107) of the control device 100 determines the contraction rate of the hydraulic actuator M based on the joint angle θi of the joint Ji according to the current position of the robot device 1 (hand unit 4). Cr1 (i) and Cr2 (i) are set (step S820 in FIG. 8). Further, the target pressure setting unit 110 (contraction force calculation unit 108) has a target torque Ttag (i) set by the target torque setting unit 105 and a target rigidity R (i) set by the target rigidity setting unit 106. Based on this, the contraction forces Fc1 (i) and Fc2 (i) of the hydraulic actuator M are calculated (step S830 in FIG. 8). Further, the target pressure setting unit 110 (target pressure derivation unit 109) has a pressure corresponding to the contraction rate Cr1 (i) and the contraction force Fc1 (i) from the target pressure setting map, and the contraction rate Cr2 (i) and the contraction force Fc2. The pressure corresponding to (i) is derived and set to the target pressures Ptag1 (i) and Ptag2 (i) (step S840 in FIG. 8). Then, the current command value setting unit 111 directly converts the target pressures Ptag1 (i) and Ptag2 (i) set by the target pressure setting unit 110 into the current command values for the first and second linear solenoid valves 151 and 152. (Step S90 in FIG. 6). This makes it possible to appropriately set the target pressures Ptag1 (i) and Ptag2 (i) according to the target torque Ttag (i) and the target rigidity R (i). The contraction rates Cr1 (i) and Cr2 (i) may be set based on the target angle of each joint Ji according to the target position of the robot device 1 (hand unit 4).

Further, the first and second linear solenoid valves 151 and 152 have a solenoid portion 15e, a spool 15s, a spring SP for urging the spool 15s, an input port 15i to which hydraulic oil is supplied, an output port 15o, and an output port 15o. It includes a feedback port 15f that communicates with the input port 15i and a drain port 15d that can communicate with the input port 15i and the output port 15o. Further, the first and second linear solenoid valves 151 and 152 are added to the spool 15s by the thrust generated by the solenoid portion 15e, the urging force of the spring SP, and the action of the hydraulic pressure supplied from the output port 15o to the feedback port 15f. The pressure of the hydraulic oil is adjusted by balancing the thrust.

This makes it possible to accurately adjust the hydraulic oil supplied to the hydraulic actuator M as an artificial muscle so that the actual pressure becomes the target pressures Ptag1 (i) and Ptag2 (i). Further, by feeding back the hydraulic pressure (signal pressure or drive pressure) supplied to the hydraulic actuator M side to the first and second linear solenoid valves 151 and 152, it is driven by a plurality of hydraulic actuators M as artificial muscles. When an external force from other than the plurality of hydraulic actuators M is applied to the robot arm 2, it is possible to absorb the fluctuation of the hydraulic pressure according to the volume change of the tube T of the hydraulic actuator M due to the external force. In addition, after the external force disappears, it becomes possible to promptly supply the required hydraulic pressure (driving pressure) to the hydraulic actuator M.

However, at least one of the first and second linear solenoid valves 151 and 152 may be a normally open valve. In this case, the normally open valve balances the thrust from the solenoid part and the thrust due to the hydraulic pressure supplied to the feedback port so as to act in the same direction as the thrust from the solenoid part with the urging force of the spring. There may be. Further, at least one of the linear solenoid valves 151-156 does not have a dedicated feedback port, and is configured so that the output pressure (driving pressure) acts on the spool as a feedback pressure inside the sleeve accommodating the spool. (For example, see JP-A-2020-41687).

Further, in the liquid supply device 10, at least one of the first and second linear solenoid valves 151 and 152 (for example, the maximum value of the required output (product of contraction force and contraction speed) is all hydraulic actuators M. The linear solenoid valve (or on / off solenoid valve) that outputs the signal pressure according to the current supplied to the solenoid part and the one corresponding to the hydraulic actuator M, which is the largest in the above, operates according to the signal pressure. It may be replaced with a control valve that regulates the pressure of oil. In this case, the control valve includes a spool arranged in the valve body, a spring for urging the spool, an input port, an output port, a feedback port, a signal pressure input port, and a drain port. It may be configured so that the output pressure (driving pressure) acts on the spool as a feedback pressure inside the spool.

Further, at least one of the first and second linear solenoid valves 151 and 152 is a flow control valve in which the hydraulic pressure (hydraulic pressure) supplied to the corresponding hydraulic actuator M is controlled to be the target pressure. It may be replaced. Further, the original pressure generation valve 14 may be omitted from the liquid supply device 10. Further, an accumulator (accumulator) for storing the hydraulic pressure generated by the pump 13 may be provided in the liquid supply device 10. Further, the liquid supply device 10 may be configured to supply a liquid other than hydraulic oil such as water to the hydraulic actuator M. In addition, the first and second linear solenoid valves 151 and 152 may be omitted from the liquid supply device 10, and a pump as a hydraulic pressure adjusting device may be provided for each of the plurality of hydraulic actuators M.

Further, in the above embodiment, the hydraulic actuator M as an artificial muscle includes a tube T to which hydraulic oil is supplied to the inside and contracts in the axial direction while expanding in the radial direction in response to an increase in the hydraulic pressure inside. Although it is a Macchiben type artificial muscle including a braided sleeve S covering the tube T, the configuration of the hydraulic actuator M in the robot device 1 is not limited to this. That is, the hydraulic actuator M may include a tube that expands in the radial direction and contracts in the axial direction when the liquid is supplied. For example, an inner tubular member formed of an elastic body and an elastic body. Axial fiber reinforced liquid containing an outer tubular member and a fiber layer arranged between the inner tubular member and the outer tubular member. It may be a pressure actuator (see, for example, Japanese Patent Application Laid-Open No. 2011-137516). Further, the hydraulic actuator M may be a liquid cylinder including a cylinder and a piston. In addition, the artificial muscle of the robot device 1 may use a gas such as air as a working fluid.

Further, the robot arm 2 of the robot device 1 may include a swing motor (for example, a swing motor that rotates the base (wrist portion) of the hand portion 4) as a hydraulic actuator (fluid actuator). That is, the robot arm 2 (robot body) may include at least one of a hydraulic actuator as an artificial muscle and a swing motor. Further, the robot arm 2 of the robot device 1 may include a fluid pressure cylinder such as an air cylinder or a hydraulic cylinder as a hydraulic actuator. Further, in the robot device 1, the tank 11 may be supported by a robot body such as a robot arm 2.

The robot device 1 may include only one joint, or may include only one or two hydraulic actuators M as artificial muscles. Further, the robot device 1 is not limited to those including a robot arm 2 having at least one hydraulic actuator M or the like and a hand portion 4, and the robot device 1 includes at least one hydraulic actuator, a tool such as a drill bit, or a switch or the like. An element other than the hand portion 4 such as a pressing member that presses the robot arm may include a robot arm attached to the hand. Further, the robot device 1 may be a walking robot, a wearable robot, or the like.

In the robot device 1, for example, when the gripping target is handed over from the other party to the hand portion 4 of the robot arm 2 stationary in the air, the target rigidity R (i) of each joint Ji of the robot arm 2 is lowered. However, the target rigidity R (i) of each joint Ji may be increased after the hand portion 4 comes into contact with the gripping object. As a result, the impact due to the contact between the hand portion 4 and the gripping object can be absorbed by each joint Ji, and the robot arm 2 can be satisfactorily suppressed from vibrating after receiving the gripping object. Further, the target rigidity R (i) of each joint Ji may be changed according to the posture of the robot arm 2 (robot device 1). For example, when the posture of the robot arm 2 becomes a posture that increases the moment acting on the robot arm 2 (for example, the joint J1 on the most proximal end side), the posture of the robot arm 2 reduces the moment acting on the robot arm 2. The target rigidity R (i) of each joint Ji may be set higher than that in the posture of the joint Ji. Further, even if an obstacle other than a human being can be detected at the installation location of the robot device 1 and an obstacle is detected around the robot device 1, the target rigidity R (i) of each joint Ji is lowered. good. Further, after the preparation for operation of the robot arm 2 is completed, the target rigidity R (i) of each joint Ji may be increased to suppress the generation of vibration at the start of operation of the robot arm 2. Further, the target rigidity R (i) of the joint Ji may be increased before the operation of the robot arm 2 is stopped to suppress the generation of vibration when the operation of the robot arm 2 is stopped. Further, the target rigidity setting unit 106 may change the target rigidity R (i) of each joint Ji according to the weight of the gripping object of the hand unit 4, for example, when the gripping object is relatively heavy. May increase the target rigidity R (i) of each joint Ji and decrease the target rigidity R (i) of each joint Ji when the gripping object is relatively light.

FIG. 13 is a block diagram showing another control device 100B applicable to the robot device 1. Of the components of the control device 100B, the same elements as those of the control device 100 described above are designated by the same reference numerals, and duplicate description will be omitted.

The control device 100B shown in FIG. 13 is also constructed by at least one of hardware such as a computer CPU, ROM, and RAM, and software such as a control program installed in the computer. As shown in the figure, the control device 100B has a target position setting unit 101, a current position derivation unit 102, a target torque setting unit 105 (torque calculation unit 103 and a gravity compensation unit 104), and a target, similarly to the control device 100. The rigidity setting unit 106 and the valve drive unit 112 are included. Further, the control device 100B includes a contraction rate setting unit 107, a contraction force calculation unit 108, and a target pressure setting unit 110B including a target pressure derivation unit 109B different from that of the control device 100, and the control device 100. It includes a different current command value setting unit 111B, a volume estimation unit 118, and a flow rate estimation unit 119.

The contraction rate setting unit 107 of the target pressure setting unit 110B is the first artificial muscle corresponding to the joint Ji based on the joint angle θi of the joint Ji according to the current position of the hand unit 4 for each joint J1-J3. The contraction rate Cr1 (i) of each hydraulic actuator M constituting AM1 and the contraction rate Cr2 (i) of each hydraulic actuator M constituting the second artificial muscle AM2 corresponding to the joint Ji are set. Further, the contraction force calculation unit 108 of the target pressure setting unit 110B has a target torque Ttag (i) set by the target torque setting unit 105 and a target rigidity set by the target rigidity setting unit 106 for each joint J1-J3. Based on R (i), the contractile force Fc1 (i) required for each hydraulic actuator M constituting the first artificial muscle AM1 and each constituting the second artificial muscle AM2 corresponding to the joint Ji. The contraction force Fc2 (i) required for the hydraulic actuator M is calculated. The target pressure derivation unit 109B has a target torque Ttag (2) indicating a force required for each hydraulic actuator M based on the contraction rates Cr1 (i) and Cr2 (i) and the contraction forces Fc1 (i) and Fc2 (i). The target pressures Ptag1 (i) and Ptag2 (i) according to i) are configured to be changed between when the tube T contracts in the axial direction and when the tube T expands in the axial direction.

The volume estimation unit 118 is set by the previous value of the target pressure Ptag1 (i) set (derived) by the target pressure setting unit 110 (target pressure derivation unit 109) and the contraction rate setting unit 107 for each joint J1-J3. Based on the contraction rate Cr1 (i), the volume V1 (i) of the tube T of each hydraulic actuator M constituting the first artificial muscle AM1 corresponding to the joint Ji is estimated (derived). Further, the volume estimation unit 118 has the previous value of the target pressure Ptag2 (i) set (derived) by the target pressure setting unit 110 (target pressure derivation unit 109) and the contraction rate setting unit 107 for each of the joints J1-J3. Based on the contraction rate Cr2 (i) set by, the volume V2 (i) of the tube T of each hydraulic actuator M constituting the second artificial muscle AM2 corresponding to the joint Ji is estimated (derived).

The flow rate estimation unit 119 is the first artificial muscle AM1 corresponding to the joint Ji based on the previous value and the current value of the volume V1 (i) estimated (derived) by the volume estimation unit 118 for each joint J1-J3. The flow rate Q1 (i) of the hydraulic oil supplied to the tube T of each hydraulic actuator M constituting the above is estimated (calculated). Further, the flow rate estimation unit 119 is a second artificial muscle corresponding to the joint Ji based on the previous value and the current value of the volume V2 (i) estimated (derived) by the volume estimation unit 118 for each joint J1-J3. The flow rate Q2 (i) of the hydraulic oil supplied to the tube T of each hydraulic actuator M constituting the muscle AM2 is estimated (calculated).

The current command value setting unit 111 is the first unit corresponding to the joint Ji based on the target pressure Ptag1 (i) set by the target pressure setting unit 110 and the flow rate Q1 (i) estimated by the flow rate estimation unit 119. A current command value (target current) for the first linear solenoid valve 151 (solenoid portion 15e) for adjusting the hydraulic pressure to each hydraulic actuator M constituting the artificial muscle AM1 is set. Further, the current command value setting unit 111 corresponds to the joint Ji based on the target pressure Ptag2 (i) set by the target pressure setting unit 110 and the flow rate Q2 (i) estimated by the flow rate estimation unit 119. A current command value (target current) is set for the second linear solenoid valve 152 (solenoid portion 15e) that adjusts the hydraulic pressure to each hydraulic actuator M constituting the second artificial muscle AM2.

Subsequently, the control procedure of the robot device 1 by the control device 100B will be described with reference to FIGS. 14 to 19. Here, the control procedure of the robot device 1 will be described by taking as an example a case where the hand portion 4 of the robot device 1 is moved to the gripping target and the hand portion 4 grips and transfers the gripping target.

Prior to the start of operation of the robot arm 2, the control device 100B executes the routine of FIG. 5 in the same manner as the control device 100 (before the start of movement of the hand unit 4) to reach the final target arrival position of the hand unit 4. (X _r , y _r , z _r ) and the target trajectory of the hand unit 4 from the initial position to the target arrival position (x _r , y _r , z _r ) are set. After setting the target arrival position and the target trajectory, the control device 100B repeatedly executes the robot arm control routine shown in FIG. 14 at predetermined time (for example, about 10 ms) in response to an execution instruction by the user. The processing of steps S10-S70 in the robot arm control routine of FIG. 14 is the same processing as the processing of steps S10-S70 in the robot arm control routine of FIG.

When the execution of the robot arm control routine of FIG. 14 is started and the target torque Ttag (i) for each joint Ji is set in step S70, the target pressure setting unit 110 of the control device 100B is set for each joint J1-J3. The target pressure Ptag1 (i) of each hydraulic actuator M constituting the first artificial muscle AM1 and the target pressure Ptag2 (i) of each hydraulic actuator M constituting the second artificial muscle AM2 are set. (Step S80B). FIG. 15 is a flowchart illustrating the setting procedure of the target pressures Ptag1 (i) and Ptag2 (i) by the target pressure setting unit 110B in step S80B. As shown in the figure, the target pressure setting unit 110B first sets the variable i, that is, the joint number to the value 1 (step S801). Next, the contraction force calculation unit 108 of the target pressure setting unit 110B has the target torque Ttag (i) for the joint Ji set by the target torque setting unit 105 and the target rigidity of the joint Ji set by the target rigidity setting unit 106. Acquire R (i) (step S802). Further, in step S802, the contraction rate setting unit 107 of the target pressure setting unit 110B acquires the current joint angle θi of the joint Ji detected by the corresponding joint angle sensor 7.

The contraction rate setting unit 107 of the target pressure setting unit 110B that has acquired the joint angle θi sets the contraction rate Cr1 (i) of each hydraulic actuator M constituting the first artificial muscle AM1 corresponding to the joint Ji and the joint Ji. The contraction rate Cr2 (i) of each hydraulic actuator M constituting the corresponding second artificial muscle AM2 is calculated (step S803). In step S803, the contraction rate setting unit 107 has contraction rates Cr1 (i) and Cr2 based on the joint angle θi of the joint Ji, the specifications of the robot arm 2 (robot device 1) (dimensions of the arm 3 and the like), and the like. (I) is derived and set.

Further, the contraction force calculation unit 108 of the target pressure setting unit 110B is the first artificial muscle corresponding to the joint Ji based on the target torque Ttag (i) acquired in step S802 and the target rigidity R (i) of the joint Ji. The contraction force (tensile force) Fc1 (i) required for each hydraulic actuator M constituting the muscle AM1 and each hydraulic actuator M constituting the second artificial muscle AM2 corresponding to the joint Ji are required. The contraction force (tensile force) Fc2 (i) is calculated (step S804). In step S804, the contraction force calculation unit 108 solves the simultaneous equations for the target torque Ttag (i), the target rigidity R (i), the contraction force Fc1 (i), and the Fc2 (i) to obtain the target torque Ttag ( The contraction forces Fc1 (i) and Fc2 (i) corresponding to the target rigidity R (i) of i) and the joint Ji are calculated.

After the process of step S804, the target pressure derivation unit 109B of the target pressure setting unit 110B changes the contraction rate Cr1 (i) of each hydraulic actuator M constituting the first artificial muscle AM1 corresponding to the joint Ji ΔCr1. (I) and the change amount ΔCr2 (i) of the contraction rate Cr2 (i) of each hydraulic actuator M constituting the second artificial muscle AM2 corresponding to the joint Ji are acquired (step S805). The amount of change ΔCr1 (i) is the difference between the current value and the previous value (current value-previous value) of the shrinkage rate Cr1 (i) calculated in step S803, that is, the calculation cycle of the shrinkage rate Cr1 (i), that is, FIG. It is obtained gradually with the execution cycle dt of the robot arm control routine of. Further, the change amount ΔCr2 (i) is obtained by gradually increasing the difference (current value-previous value) between the current value and the previous value of the shrinkage rate Cr2 (i) calculated in step S803 in the execution cycle dt. It is a thing. In the present embodiment, the change amounts ΔCr1 (i) and ΔCr2 (i) are calculated by the shrinkage rate setting unit 107, and the target pressure derivation unit 109B changes the change amounts ΔCr1 (i) and ΔCr2 (from the shrinkage rate setting unit 107). i) Get.

Further, the target pressure derivation unit 109B is a map for setting the target pressure Ptag1 (i) based on the sign of the change amount ΔCr1 (i), which is the first target pressure setting map and the figure shown by the alternate long and short dash line in FIG. The first and second maps for setting the target pressure Ptag2 (i) based on the sign of the change amount ΔCr2 (i) while selecting one of the second target pressure setting maps shown by the two-dot chain line in 16. Select one of the target pressure setting maps (step S806). Here, each hydraulic actuator M of the robot device 1 includes a tube T that expands in the radial direction and contracts in the axial direction in response to an increase in the pressure of the hydraulic oil inside. Therefore, even if the hydraulic pressure and the contraction rate in the tube T are the same, each hydraulic actuator M has when the tube T contracts in the axial direction and when it expands in the axial direction (when it returns to the natural length side). It has a so-called hysteresis characteristic that the contraction force generated by and is different. That is, the hydraulic pressure supplied to the tube T that contracts in the axial direction (see the alternate long and short dash line in FIG. 16) and the hydraulic pressure supplied to the tube T that extends in the axial direction (see the alternate long and short dash line in FIG. 16) are the same. When the contraction rate of the tube T that contracts in the axial direction and the contraction rate of the tube T that expands in the axial direction are the same, the contraction force generated by the tube T that contracts in the axial direction expands in the axial direction. It is smaller than the contraction force generated by the tube T.

Based on this, in the present embodiment, the first and second target pressure setting maps are tested in advance as maps showing the static characteristics of the hydraulic actuator M for setting the target pressures Ptag1 (i) and Ptag2 (i).・ Prepared after analysis. The first target pressure setting map defines the relationship between the contraction rate of the tube T that contracts in the axial direction and the contraction force generated by the tube T for each hydraulic pressure supplied to the tube T of the hydraulic actuator M. There is (see the alternate long and short dash line in FIG. 16). Further, the second target pressure setting map defines the relationship between the contraction rate of the tube T extending in the axial direction and the contraction force generated by the tube T for each hydraulic pressure supplied to the tube T of the hydraulic actuator M. (See the two-dot chain line in FIG. 16). As can be seen from FIG. 16, the first target pressure setting map considers the hysteresis characteristics of the fluid actuator M and sets the target pressures Ptag1 (i) and Ptag2 (i) when the contraction rate and the contraction force are the same. It is created to be larger than the second target pressure setting map.

In step S806, when the target pressure derivation unit 109B has a positive sign of the change amount ΔCr1 (i), that is, when the tube T of each hydraulic actuator M constituting the first artificial muscle AM1 is contracted. When the first target pressure setting map is selected and the sign of the change amount ΔCr1 (i) is negative, that is, when the tube T of each hydraulic actuator M constituting the first artificial muscle AM1 is extended, the first 2 Select the target pressure setting map. Further, in step S806, in the target pressure derivation unit 109B, when the sign of the change amount ΔCr2 (i) is positive, that is, the tube T of each hydraulic actuator M constituting the second artificial muscle AM2 is contracted. When the first target pressure setting map is selected and the sign of the change amount ΔCr2 (i) is negative, that is, when the tube T of each hydraulic actuator M constituting the second artificial muscle AM2 is extended. , Select the second target pressure setting map.

Next, the target pressure derivation unit 109B has a shrinkage rate Cr1 (i) calculated in step S803 from the first or second target pressure setting map selected according to the sign of the change amount ΔCr1 (i) in step S804. Target pressure Ptag1 (i) of each hydraulic actuator M constituting the first artificial muscle AM1 corresponding to the joint Ji by deriving the pressure corresponding to the calculated contraction force Fc1 (i) while performing linear interpolation as appropriate. (Step S807). Further, in step S807, the target pressure derivation unit 109B has the shrinkage rate Cr1 (i) calculated in step S803 from the first or second target pressure setting map selected according to the sign of the change amount ΔCr2 (i). The pressure corresponding to the contraction force Fc1 (i) calculated in step S804 is derived while performing linear interpolation as appropriate, and the target pressure of each hydraulic actuator M constituting the second artificial muscle AM2 corresponding to the joint Ji Set to Ptag2 (i). As described above, the target pressures Ptag1 (i) and Ptag2 are set to the pressures corresponding to the contraction rates Cr1 (i) and Cr2 (i) and the contraction forces Fc1 (i) and Fc2 (i) of the tube T while considering the above-mentioned hysteresis characteristics. By setting to (i), it becomes possible to accurately set the target pressures Ptag1 (i) and Ptag2 (i) in response to the request to the robot arm 2.

When the target pressures Ptag1 (i) and Ptag2 (i) are set in step S807, the target pressure setting unit 110B increments the variable i (step S808), and the variable i has a value N + 1 (here, N = 3). ) Or not (step S809). When the target pressure setting unit 110B determines that the variable i is less than the value N + 1 (step S809: NO), the process of the above steps S802-S809 is executed again. Further, when the target pressure setting unit 110B determines that the variable i is the value N + 1 or more (step S809: YES), the setting of the target pressures Ptag1 (i) and Ptag2 (i) of each hydraulic actuator M is completed. ..

Further, as shown in FIG. 14, the control device 100B is subjected to the first artificial operation for each joint J1-J3 after setting the target pressures Ptag1 (i) and Ptag2 (i) or partially in parallel with step S80B. The flow rate Q1 (i) of the hydraulic oil supplied to the tube T of each hydraulic actuator M constituting the muscle AM1 and the hydraulic oil supplied to the tube T of each hydraulic actuator M constituting the second artificial muscle AM2. Estimate (derive) the flow rate Q2 (i) of (step S85). FIG. 17 is a flowchart illustrating the estimation procedure of the flow rates Q1 (i) and Q2 (i) in step S85. As shown in the figure, the volume estimation unit 118 of the control device 100B first sets the variable i, that is, the joint number to the value 1 in order to estimate the flow rates Q1 (i) and Q2 (i) (step S851). ).

After the process of step S851, the volume estimation unit 118 has the target pressures Ptag1 (i) and Ptag2 (i), that is, the target for the joint Ji set by the target pressure setting unit 110B at the time of the previous execution of the robot arm control routine of FIG. The previous values of the pressures Ptag1 (i) and Ptag2 (i) and the shrinkage rates Cr1 (i) and Cr2 (i) set by the shrinkage rate setting unit 107 in step S803 of FIG. 15 are acquired (step S852). .. The previous values of the target pressures Ptag1 (i) and Ptag2 (i) are the current hydraulic pressure in the tube T of each hydraulic actuator M constituting the first artificial muscle AM1 corresponding to the joint Ji, or the second artificial muscle. It is used to indicate the current hydraulic pressure in the tube T of each hydraulic actuator M constituting AM2.

Further, the volume estimation unit 118 uses the volume estimation map illustrated in FIG. 18 to obtain the volume V1 (i) of the tube T of each hydraulic actuator M constituting the first artificial muscle AM1 corresponding to the joint Ji. The volume V2 (i) of the tube T of each hydraulic actuator M constituting the second artificial muscle AM2 corresponding to the joint Ji is estimated (step S853). As shown in FIG. 18, the volume estimation map is experimentally and analyzed in advance so as to define the relationship between the pressure (internal pressure) of the hydraulic oil in the tube T and the volume of the tube T for each contraction rate of the tube T. It was created through. In step S853, the volume estimation unit 118 appropriately performs linear interpolation from the volume estimation map, and sets the volume corresponding to the previous value of the target pressure Ptag1 (i) and the shrinkage rate Cr1 (i) acquired in step S852 as the volume V1 ( Derived as i). Further, in step S853, the volume estimation unit 118 sets the volume corresponding to the previous value of the target pressure Ptag2 (i) and the shrinkage rate Cr2 (i) acquired in step S852 while performing linear interpolation as appropriate from the volume estimation map. It is derived as the volume V2 (i).

When the volumes V1 (i) and V2 (i) are estimated, the hydraulic oil supplied to the tube T of each hydraulic actuator M constituting the first artificial muscle AM1 corresponding to the joint Ji by the flow rate estimation unit 119. The flow rate Q1 (i) and the flow rate Q2 (i) of the hydraulic oil supplied to the tube T of each hydraulic actuator M constituting the second artificial muscle AM2 are estimated (step S854). In step S854, the flow rate estimation unit 119 estimates the current values of the volumes V1 (i) and V2 (i) estimated by the volume estimation unit 118 in step S853, and the volume estimation at the time of the previous execution of the robot arm control routine of FIG. The previous values of the volumes V1 (i) and V2 (i) estimated by the unit 118, that is, the volumes V1 (i) and V2 (i) are acquired. Further, in step S854, the flow rate estimation unit 119 divides the value obtained by subtracting the previous value from the current value of the volume V1 (i) by the execution cycle dt (predetermined time) of the robot arm control routine (volume change amount dV1 /. dt = {this time V1 (i) -previous V1 (i)} / dt) is derived as the flow rate Q1 (i), and the value obtained by subtracting the previous value from the current value of the volume V2 (i) is executed by the robot arm control routine. The value divided by the period dt (volume change amount dV2 / dt = {current V2 (i) -previous V2 (i)} / dt) is derived as the flow rate Q2 (i).

When the flow rates Q1 (i) and Q2 (i) are estimated, the flow rate estimation unit 119 increments the variable i (step S855) and determines whether or not the variable i is equal to or greater than the value N + 1 (here, N = 3). Determination (step S856). When the flow rate estimation unit 119 determines that the variable i is less than the value N + 1 (step S856: NO), the volume estimation unit 118 and the flow rate estimation unit 119 execute the process of step S852-S856 again. Further, when the flow rate estimation unit 119 determines that the variable i is the value N + 1 or more (step S856: YES), the flow rates of the hydraulic oil supplied to the tube T of each hydraulic actuator M Q1 (i), Q2 (step S856: YES). i) The estimation is completed.

As shown in FIG. 14, when the target pressures Ptag1 (i) and Ptag2 (i) are set in step S80B and the currents Q1 (i) and Q2 (i) are estimated in step S85, the control device 100B The current command value setting unit 111B of the above sets the current command value for the solenoid units 15e of the plurality of first and second linear solenoid valves 151 and 152, respectively, by using the current command value setting map illustrated in FIG. 19 (step). S90B). As shown in FIG. 19, the current command value setting map shows the flow rate of the hydraulic oil supplied to the tube T (Q1 (i), Q2 (i)) and the tube for each current value applied to the electromagnetic part 15e. It was created through experiments and analysis in advance so as to define the relationship with the pressure of the hydraulic oil in T (target pressures Ptag1 (i) and Ptag2 (i)). As shown in FIG. 19, in the current command value setting map, the higher the pressure of the hydraulic oil to be supplied to the tube T, that is, the target pressures Ptag1 (i) and Ptag2 (i), the larger the current value and the tube. When the hydraulic oil is supplied to T (when the flow rate is positive), the same target pressures Ptag1 (i) and Ptag2 are compared with when the hydraulic oil flows out from the tube T (when the flow rate is negative). It is created so as to increase the current value corresponding to (i)). Further, the current command value setting map becomes the same target pressure Ptag1 (i), Ptag2 (i) as the flow rate (Q1 (i), Q2 (i)) increases (as the flow rate changes from negative to positive). Created to increase the corresponding current value.

In step S90B, the current command value setting unit 111B has a current value corresponding to the target pressure Ptag1 (i) set in step S80B from the current command value setting map and the flow rate Q1 (i) estimated in step S85. Is derived while performing linear interpolation as appropriate, and is set to the current command value to each first linear solenoid valve 151 corresponding to each hydraulic actuator M constituting the first artificial muscle AM1. Further, in step S90B, the current command value setting unit 111B corresponds to the target pressure Ptag2 (i) set in step S80B from the current command value setting map and the flow rate Q2 (i) estimated in step S85. The current value is derived while performing linear interpolation as appropriate, and is set to the current command value for each second linear solenoid valve 152 corresponding to each hydraulic actuator M constituting the second artificial muscle AM2. The current command value derived by the current command value setting unit 111B is given to the valve drive unit 112 of the control device 100B, and the valve drive unit 112 has a plurality of first and second linear solenoids, respectively, based on the current command. The valves 151 and 152 are controlled (PWM control) (step S100).

As a result, the current command value to the liquid supply device 10 according to the target torque Ttag (i) is easily and quickly set, and the first and second linears of the liquid supply device 10 are controlled based on the current command value. Each of the solenoid valves 151 and 152 produces a hydraulic pressure corresponding to the corresponding target pressure Ptag1 (i) or Ptag2 (i). Further, the hydraulic oil regulated by each of the first and second linear solenoid valves 151 and 152 is supplied to the tube T of the corresponding hydraulic actuator M. As a result, the flow rate control valve adjusts the flow rate of the hydraulic oil and supplies it into the tube T, or the hydraulic pressure supplied to the tube T is detected by the pressure sensor so that the actual hydraulic pressure matches the target pressure. The hydraulic pressure supplied to each tube T within a short time from the setting of the target pressures Ptag1 (i) and Ptag2 (i) is applied to the target pressures Ptag1 (i) and Ptag2 (i), as compared with the case of feedback control. It is possible to substantially match i) so that the actual shrinkage rate of each tube T can be made to follow the required value with good responsiveness and high accuracy.

After the process of step S100, the control device 100B temporarily terminates the routine of FIG. 14, and executes the process of step S10 and subsequent steps again according to the arrival of the next execution timing. On the other hand, in step S40 of FIG. 18, when it is determined by the torque calculation unit 103 that the current position of the hand unit 4 has not substantially changed from the previous position, it is determined after the current position does not substantially change. The processes of steps S65 and S70-S100 are executed until the time elapses. Further, when a predetermined time elapses after the current position does not substantially change, the control device 100B ends the routine shown in FIG. 14 and executes a hand control routine for causing the hand unit 4 to grip the gripping object. Then, when the gripping target is gripped by the hand unit 4 and the hand control routine is completed, the control device 100B re-executes the routine of FIG. 14 in order to convey the gripping target to the mounting position by the robot arm 2.

As described above, the control device 100B sets the target pressures Ptag1 (i) and Ptag2 (i) of the hydraulic oil supplied to each hydraulic actuator M (step S80B in FIG. 14 and FIG. 15), and the target pressure. The current command value is set based on Ptag1 (i) and Ptag2 (i) and the flow rates Q1 (i) and Q2 (i) of the hydraulic oil supplied to each hydraulic actuator M (step S90B in FIG. 14). Each of the first and second linear solenoid valves 151 and 152 is controlled based on the current command value (step S100 in FIG. 14). As a result, while suppressing deterioration of the responsiveness of the operation of each hydraulic actuator M as an artificial muscle due to excess or deficiency of the flow rates Q1 (i) and Q2 (i) of the hydraulic oil supplied to the tube T, each The hydraulic oil having a pressure corresponding to the target pressures Ptag1 (i) and Ptag2 (i) can be supplied to the hydraulic actuator M. That is, according to the research and analysis by the present inventors, the current command value is set based on the target pressures Ptag1 (i) and Ptag2 (i) and the flow rates Q1 (i) and Q2 (i). Compared with the case where the target pressures Ptag1 (i) and Ptag2 (i) are directly converted into the current command value without considering the flow rates Q1 (i) and Q2 (i), the responsiveness of the operation of each hydraulic pressure actuator M and It has been confirmed that the followability of the hydraulic pressure in each tube T to the target pressures Ptag1 (i) and Ptag2 (i) can be improved. As a result, in the robot device 1 including the control device 100B, it is possible to operate a plurality of hydraulic actuators M that are operated by receiving the supply of hydraulic oil with good responsiveness and high accuracy, and the robot arm 2 is responsive and stable. Can be activated.

Further, each hydraulic actuator M of the robot device 1 includes a tube T to which hydraulic oil is supplied to the inside and contracts in the axial direction while expanding in the radial direction in response to an increase in internal pressure. Further, the flow rate estimation unit 119 of the control device 100B calculates the volume change amount (dV1 / dt, dV2 / dt) of the tube T as the flow rates Q1 (i) and Q2 (i) (steps S85 and 16 in FIG. 14). ). Further, the current command value setting unit 111B of the control device 100B has a current command value for each first linear solenoid valve 151 corresponding to the first artificial muscle AM1 based on the target pressure Ptag1 (i) and the flow rate Q1 (i). And set the current command value for each second linear solenoid valve 152 corresponding to the second artificial muscle AM2 based on the target pressure Ptag2 (i) and the flow rate Q2 (i) (step S90B in FIG. 14). ). As a result, the current command value is appropriately set according to the flow rates Q1 (i) and Q2 (i) of the hydraulic oil supplied to each hydraulic actuator M, and the first and second linear solenoid valves 151 and 152 are set. It is possible to accurately adjust the pressure of the hydraulic oil supplied to each hydraulic actuator M so as to be the target pressures Ptag1 (i) and Ptag2 (i).

Further, the control device 100B repeatedly executes the robot arm control routine of FIG. 14 at predetermined time (for example, about 10 ms) to set the target pressures Ptag1 (i) and Ptag2 (i). Further, the volume estimation unit 118 of the control device 100B is based on the previous values of the target pressures Ptag1 (i) and Ptag2 (i) and the shrinkage rates Cr1 (i) and Cr2 (i) of the tube T. Volumes V1 (i) and V2 (i) are calculated (step S85 in FIG. 14, steps S852 and S853 in FIG. 17). Further, the flow rate estimation unit 119 of the control device 100B divides the difference between the current value and the previous value of the volumes V1 (i) and V2 (i) of the tube T by the predetermined time (execution cycle dt of the routine in FIG. 8). Then, the flow rates Q1 (i) and Q2 (i) are calculated (step S85 in FIG. 8 and step S854 in FIG. 17). This makes it possible to appropriately calculate the flow rates Q1 (i) and Q2 (i) of the hydraulic oil supplied to each hydraulic actuator M.

Further, the target pressure setting unit 110B of the control device 100B sets the target pressures Ptag1 (i) and Ptag2 (i) according to the target torque Ttag (i) indicating the force required for each hydraulic actuator M by the tube T. It is changed between when it contracts in the axial direction and when the tube T expands in the axial direction (steps S805-S807 in FIG. 15). This makes it possible to satisfactorily suppress the deviation between the force (torque) output from each hydraulic actuator M and the required force (torque) due to the hysteresis characteristic.

Further, the target pressure derivation unit 109B of the target pressure setting unit 110B has the target pressures Ptag1 (i) and Ptag2 based on the contraction rates Cr1 (i) and Cr2 (i) and the contraction forces Fc1 (i) and Fc2 (i). (I) is derived and set (step S807 in FIG. 15). Further, the target pressure derivation unit 109B of the hydraulic oil supplied to the tube T when the changes in the shrinkage rates Cr1 (i) and Cr2 (i) ΔCr1 (i) and ΔCr2 (i) are positive values. A first target pressure setting map (first target pressure setting map) that defines the relationship between the contraction rates Cr1 (i) and Cr2 (i) of the tube T that contracts in the axial direction for each pressure and the contraction forces Fc1 (i) and Fc2 (i). The target pressures Ptag1 (i) and Ptag2 (i) are set using the constraint) (steps S805-S807 in FIG. 15). Further, the target pressure derivation unit 109B contracts the tube T that extends axially according to the pressure of the hydraulic oil supplied to the tube T when the changes ΔCr1 (i) and ΔCr2 (i) are negative values. The target pressure Ptag1 (i), using the second target pressure setting map (second constraint) that defines the relationship between the rates Cr1 (i), Cr2 (i) and the contraction forces Fc1 (i), Fc2 (i), Ptag2 (i) is set (steps S805-S807 in FIG. 15). This makes it possible to appropriately set the target pressures Ptag1 (i) and Ptag2 (i) while reducing the influence of the hysteresis characteristic of the hydraulic actuator M. In the robot device 1, the contraction rate setting unit 107 of the tube T has contraction rates Cr1 (i) and Cr2 (i) based on the target angle of each joint Ji according to the target position of the hand unit 4 (robot device 1). ) May be set.

[Summary of forms for carrying out the invention]
As described above, the robot device according to the embodiment of the present disclosure receives two links (3, 5) connected via joints (J1, J2, J3, Ji) and a liquid supply. The pressure of the pair of artificial muscles (M, AM1, AM2) that relatively rotate the two links (3, 5) and the liquid supplied to the artificial muscles (M, AM1, AM2) is adjusted. A hydraulic pressure adjusting device (151, 152) and a target rigidity setting unit (106) for setting a target rigidity (R (i)) of the joints (J1, J2, J3, Ji) are included, and the target rigidity (R (R) Based on i)), the target pressures (Ptag1 (i), Ptag2 (i)) of the liquid supplied to the artificial muscle (M, AM1, AM2) are set, and the artificial muscle (M, AM1, AM2) is set. ) With a control device (100, 100B) that controls the hydraulic pressure adjusting device (151, 152) so that the pressure of the liquid supplied to the target pressure (Ptag1 (i), Ptag2 (i)) becomes the target pressure. It is a robot device (1) including.

That is, the force to be output from the artificial muscle in order to rotate the two links relatively can be determined from the target rigidity of the joint connecting the two links. Then, if the target pressure of the hydraulic pressure to the artificial muscle is set based on the target rigidity and the hydraulic pressure adjusting device is controlled based on the target pressure, the artificial muscle is responsive so as to output the required force. It is possible to operate it with high accuracy. As a result, the rigidity of the joint can be changed with high accuracy in a responsive manner, so that the rigidity of the joint can be reduced to allow the required torque output, or the joint can be stabilized in the operation of the robot device. It is possible to increase the rigidity of the. As a result, the robot device including two links connected via joints and a pair of artificial muscles that operate by receiving a liquid supply and rotate the two links relatively is responsive and stable. Can be activated.

Further, the target rigidity setting unit (106) may set the target rigidity (R (i)) at least based on the target position or the current position of the robot device (1).

As a result, at the position where a large torque is required to relatively rotate the two links connected via the joint, the target rigidity of the joint is lowered to allow the output of the required torque. At a position where a large torque is not required to rotate the two links relatively, it is possible to increase the target rigidity of the joint in order to stabilize the operation of the robot device.

Further, when the robot device (1) is moved to the target, the target rigidity setting unit (106) has the target rigidity (R (i)) according to the positional relationship between the robot device (1) and the target. ) May be changed.

This makes it possible to operate the robot device in a responsive and stable manner and move the hand or the like of the robot device toward the gripping target or the like.

Further, the target rigidity setting unit (106) may reduce the target rigidity (R (i)) before a part of the robot device (1) comes into contact with the target.

This makes it possible for the joints to better absorb the impact when the hand or the like of the robot device comes into contact with the gripping object or the like.

Further, the target rigidity setting unit (106) may change the target rigidity (R (i)) according to at least one of the moving speed and the acceleration of the robot device (1).

As a result, the target rigidity of the joint is lowered to allow acceleration and high-speed movement of the robot device (hands, etc.), and when the robot device decelerates or moves at low speed, the target rigidity of the joint is increased to suppress the generation of vibration. It becomes possible to do.

Further, the target rigidity setting unit (106) may reduce the target rigidity (R (i)) when there is a person around the robot device (1).

As a result, even if a person comes into contact with the robot device, the impact caused by the contact received by the person can be satisfactorily mitigated.

Further, the two links (3, 5) may be relatively rotated by the pair of artificial muscles (M, AM1, AM2) arranged so as to antagonize each other.

As a result, one of the two links connected via the joint by a pair of artificial muscles can be rotated with respect to the other with good responsiveness and high accuracy, and the rigidity of the joint can be brought close to the target rigidity. It will be possible.

Further, the control device (100, 100B) includes a target torque setting unit (105) for setting a target torque (Ttag (i)) for relatively rotating the two links (3, 5). The target pressure (Ptag1 (i), Ptag2 (i)) is set based on the target torque (Ttag (i)) and the target rigidity (R (i)). You may.

Further, the control device (100) determines the contraction rate (Cr1 (i), Cr2 (i)) of the artificial muscle (M, AM1, AM2) based on the current position or the target position of the robot device (1). At the same time, the target torque (Ttag (i)) set by the target torque setting unit (105) and the target rigidity (R (i)) set by the target rigidity setting unit (106) are set. Based on this, the contraction force (Fc1 (i), Fc2 (i)) of the artificial muscle (M, AM1, AM2) is calculated, and the contraction rate (Cr1 (i), Cr2 (i)) and the contraction force (Fc1). It is set by the target pressure setting unit (110) that sets the target pressure (Ptag1 (i), Ptag2 (i)) based on (i) and Fc2 (i), and the target pressure setting unit (110). Even if it further includes a command value setting unit (11) that directly converts the target pressures (Ptag1 (i), Ptag2 (i)) into command values to the hydraulic pressure adjusting device (151, 152). good.

This makes it possible to properly set the target pressure according to the target torque and target rigidity.

Further, the hydraulic pressure adjusting device (151, 152) may be one that adjusts the pressure of the liquid supplied to the artificial muscles (M, AM1, AM2) by receiving the supply of current, and the control may be performed. The device (100B) has a target pressure (Ptag1 (i), Ptag2 (i)) and a flow rate of the liquid supplied to the artificial muscles (M, AM1, AM2) (Q1 (i), Q2 (i). ) And the current command value may be set, and the hydraulic pressure adjusting device (151, 152) may be controlled based on the current command value.

As a result, it is possible to supply the artificial muscle with the liquid at the required pressure while suppressing the deterioration of the responsiveness of the movement of the artificial muscle due to the excess or deficiency of the flow rate, so that the artificial muscle operates by being supplied with the liquid. It is possible to operate the artificial muscle with high responsiveness and high accuracy.

Further, even if the artificial muscle (M) includes a tube (T) to which the liquid is supplied to the inside and contracts in the axial direction while expanding in the radial direction in response to an increase in the pressure inside the artificial muscle (M). good.

Further, in the control device (100B), the tube (T) applies the target pressures (Ptag1 (i), Ptag2 (i)) according to the force required for the artificial muscles (M, AM1, AM2). It may be changed between when the tube (T) contracts in the axial direction and when the tube (T) expands in the axial direction.

This makes it possible to satisfactorily suppress the deviation between the force (torque) output from the artificial muscle and the required force (torque) due to the hysteresis characteristic.

Further, the hydraulic pressure adjusting device includes a solenoid portion (15e), a spool (15s), a spring (SP) for urging the spool (15s), an input port (15i) to which the liquid is supplied, and an output port (15o). , A solenoid valve (151, 152) including a feedback port (15f) communicating with the output port (15o) and a drain port (15d) communicating with the input port (15i) and the output port (15o). The solenoid valve (151, 152) may be the thrust generated by the solenoid portion (15e), the urging force of the spring (SP), and the feedback port (15f) from the output port (15o). ), The pressure of the liquid may be adjusted by balancing the thrust applied to the spool (15s) by the action of the hydraulic pressure supplied to the spool (15s).

Further, the robot device (1) includes a robot arm (2) having the two links (3, 5), the pair of artificial muscles (M, AM1, AM2), and a hand portion (4). It may be a thing.

Further, the target rigidity setting unit (106) may change the target rigidity (R (i)) according to the weight of the gripping object of the hand unit (104).

Further, the target rigidity (R (i)) makes it difficult for the joints (J1, J2, J3, Ji) to move with respect to an external force that tries to relatively rotate the two links (3, 5). It may be shown.

The control method of the robot device according to the embodiment of the present disclosure includes two links (3, 5) connected via joints (J1, J2, J3, Ji) and the above two links by receiving a liquid supply. A pair of artificial muscles (M, AM1, AM2) that relatively rotate (3, 5) and a hydraulic pressure adjusting device that adjusts the pressure of the liquid supplied to the artificial muscles (M, AM1, AM2). In the control method of the robot device (1) including (151, 152), the target rigidity (R (i)) of the joints (J1, J2, J3, Ji) is set, and the target rigidity (R (R)) is set. The target pressures (Ptag1 (i), Ptag2 (i)) of the liquid supplied to the artificial muscle (M, AM1, AM2) are set based on i)), and the artificial muscle (M, AM1, AM2) is set. The hydraulic pressure adjusting device (151, 152) is controlled so that the pressure of the liquid supplied to the target pressure (Ptag1 (i), Ptag2 (i)) becomes the target pressure.

According to such a method, a robot device including two links connected via a joint and a pair of artificial muscles that operate by receiving a liquid supply and rotate the two links relatively is responsive. It can be operated well and stably.

It goes without saying that the invention of the present disclosure is not limited to the above-described embodiment, and various changes can be made within the scope of the extension of the present disclosure. Further, the above embodiment is merely a specific embodiment of the invention described in the column of the outline of the invention, and does not limit the elements of the invention described in the column of the outline of the invention.

The invention of the present disclosure can be used in the manufacturing industry of robot devices including artificial muscles.

Claims (17)

1. Two links connected via joints and
   A pair of artificial muscles that rotate the two links relatively in response to the supply of liquid,
   A hydraulic pressure adjusting device that adjusts the pressure of the liquid supplied to the artificial muscle, and
   The target rigidity setting unit for setting the target rigidity of the joint is included, the target pressure of the liquid supplied to the artificial muscle is set based on the target rigidity, and the pressure of the liquid supplied to the artificial muscle is set. A control device that controls the hydraulic pressure adjusting device so as to reach the target pressure,
   A robot device equipped with.
2. In the robot device according to claim 1,
   The target rigidity setting unit is a robot device that sets the target rigidity based on at least a target position or a current position of the robot device.
3. In the robot device according to claim 1 or 2.
   The target rigidity setting unit is a robot device that changes the target rigidity according to the positional relationship between the robot device and the target when the robot device is moved to the target.
4. In the robot device according to claim 3,
   The target rigidity setting unit is a robot device that lowers the target rigidity before a part of the robot device comes into contact with the target.
5. In the robot device according to any one of claims 1 to 4.
   The target rigidity setting unit is a robot device that changes the target rigidity according to at least one of the moving speed and the acceleration of the robot device.
6. In the robot device according to any one of claims 1 to 5,
   The target rigidity setting unit is a robot device that lowers the target rigidity when there is a person around the robot device.
7. In the robot device according to any one of claims 1 to 6.
   The two links are robotic devices that are relatively rotated by the pair of artificial muscles arranged to antagonize each other.
8. In the robot device according to any one of claims 1 to 7.
   The control device further includes a target torque setting unit for setting a target torque for relatively rotating the two links, and a robot device for setting the target pressure based on the target torque and the target rigidity. ..
9. In the robot device according to claim 8,
   The control device is
   The contraction rate of the artificial muscle is set based on the current position or the target position of the robot device, the target torque set by the target torque setting unit, and the target rigidity set by the target rigidity setting unit. A target pressure setting unit that calculates the contraction force of the artificial muscle based on the above and sets the target pressure based on the contraction rate and the contraction force.
   A robot device further including a command value setting unit that directly converts the target pressure set by the target pressure setting unit into a command value to the hydraulic pressure adjusting device.
10. In the robot device according to any one of claims 1 to 8.
    The hydraulic pressure adjusting device adjusts the pressure of the liquid supplied to the artificial muscle by receiving an electric current.
    The control device is a robot device that sets a current command value based on the target pressure and the flow rate of the liquid supplied to the artificial muscle, and controls the hydraulic pressure adjusting device based on the current command value.
11. In the robot device according to any one of claims 1 to 9.
    The artificial muscle is a robot device including a tube to which the liquid is supplied to the inside and contracts in the axial direction while expanding in the radial direction in response to an increase in the pressure inside the artificial muscle.
12. In the robot device according to claim 11,
    The control device is a robot device that changes the target pressure according to the force required for the artificial muscle between when the tube contracts in the axial direction and when the tube expands in the axial direction.
13. In the robot device according to any one of claims 1 to 12,
    The hydraulic pressure adjusting device includes a solenoid part, a spool, a spring for urging the spool, an input port to which the liquid is supplied, an output port, a feedback port communicating with the output port, and the input port and the output port. It is a solenoid valve including a drain port that can communicate with
    The solenoid valve balances the thrust generated by the solenoid portion, the urging force of the spring, and the thrust applied to the spool by the action of the hydraulic pressure supplied from the output port to the feedback port to obtain the liquid. A robot device that regulates the pressure of.
14. In the robot device according to any one of claims 1 to 13.
    A robot device including a robot arm having the two links, the pair of artificial muscles, and a hand portion.
15. In the robot device according to claim 14,
    The target rigidity setting unit is a robot device that changes the target rigidity according to the weight of the gripping object of the hand unit.
16. The robot device according to any one of claims 1 to 15.
    The target rigidity is a robot device that indicates difficulty in moving the joint with respect to an external force that attempts to relatively rotate the two links.
17. Two links connected via joints, a pair of artificial muscles that receive a liquid supply and rotate the two links relatively, and a liquid that regulates the pressure of the liquid supplied to the artificial muscles. It is a control method of a robot device including a pressure adjusting device.
    The target rigidity of the joint is set, the target pressure of the liquid supplied to the artificial muscle is set based on the target rigidity, and the pressure of the liquid supplied to the artificial muscle becomes the target pressure. A method for controlling a robot device that controls the hydraulic pressure adjusting device.

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