Robot device and ultrasound diagnostic system

Abstract

This robot device comprises: a robot body; a driving unit that drives the robot body; an external force detecting unit that detects an external force acting on the robot body; and a control unit that transitions to a safe state for controlling the driving unit so that the robot body performs an evacuation action in a prescribed direction when an external force acting on the robot body has been detected by the external force detecting unit.

Description

Robotic device and ultrasound diagnostic system

[0001] This specification discloses a robotic device and an ultrasound diagnostic system.

[0002] A conventional robotic device of this type includes a collision detection unit that detects when the robot collides with an object, a first control unit that executes deceleration control to drive each motor of the robot to decelerate when it detects that the robot has collided with an object, and a second control unit that executes dynamic braking for a predetermined period of time after the deceleration control is executed, by stopping the supply of power to each motor and shorting the power input / output terminals of each motor (see, for example, Patent Document 1). This robotic device can quickly decelerate the robot when it collides with an object, thereby preventing injury to the worker. Furthermore, the worker can push the robot to move or move away from the robot while dynamic braking is being executed.

[0003] Japanese Patent Application Laid-Open No. 2019-014008

[0004] However, in the above-mentioned robot device, when the robot collides with a worker, simply slowing down each motor of the robot or applying dynamic braking may result in the force (pushing force) applied from the robot to the worker remaining, and there may be cases where the safety of the worker cannot be sufficiently ensured.

[0005] A primary object of the present disclosure is to provide a robotic device or an ultrasound diagnostic system including a robotic device that can improve safety against collisions between the robot and an object.

[0006] The present disclosure has adopted the following means to achieve the above-mentioned main object.

[0007] The robot device of the present disclosure comprises: a robot body; a drive unit that drives the robot body; an external force detection unit that detects an external force acting on the robot body; and a control unit that transitions to a safe state by controlling the drive unit so that the robot body performs a retreat operation in a predetermined direction when an external force acting on the robot body is detected by the external force detection unit.

[0008] The robot device disclosed herein controls the drive unit to cause the robot body to retreat in a predetermined direction when an external force acting on the robot body due to contact with an object is detected, thereby reducing the pushing force of the robot body when the robot body collides with an object, thereby further improving the safety of workers and the like.

[0009] The ultrasound diagnostic system of the present disclosure includes an ultrasound probe and the robotic device of the present disclosure that holds the ultrasound probe at its hand, and therefore can achieve the same effects as the robotic device of the present disclosure.

[0010] FIG. 1 is an external perspective view of an ultrasound diagnostic system including a robot device of the present embodiment; FIG. 2 is a side view of the robot device; FIG. 3 is a block diagram showing the electrical connection relationship between the robot device and an ultrasound diagnostic device; FIG. 4 is an explanatory diagram showing the movement trajectory of an ultrasound probe; FIG. 5 is a flowchart showing an example of a collision determination process; FIG. 6 is an explanatory diagram explaining a restricted area; FIG. 7 is a flowchart showing an example of a safety process; and FIG. 8 is an explanatory diagram showing the compensation torques of the lift axis J1 and each joint axis J2 to J7 set in a normal state and a safe state, respectively.

[0011] Next, embodiments of the present disclosure will be described with reference to the drawings.

[0012] Fig. 1 is a perspective view of the appearance of an ultrasound diagnostic system 10 including a robotic device 20 according to this embodiment. Fig. 2 is a side view of the robotic device 20. Fig. 3 is a block diagram showing the electrical connection between the robotic device 20 and an ultrasound diagnostic device 100. In Fig. 1, the left-right direction is the X-axis, the front-back direction is the Y-axis, and the up-down direction is the Z-axis.

[0013] In the ultrasound diagnostic system 10 of this embodiment, an ultrasound probe 101 is held at the tip of a robot arm 21, and the robot device 20 is operated so that the ultrasound probe 101 is pressed against the surface of a patient's body to acquire ultrasound echo images. This ultrasound diagnostic system 10 is used, for example, in catheter treatment. An operator (surgeon) operating a catheter guidewire presses the ultrasound probe 101 against the surface of the patient's thigh and advances the guidewire while recognizing the positional relationship between the tip of the guidewire and the blood vessel from the obtained ultrasound echo image, thereby allowing the guidewire to accurately pass through the center of an occluded or narrowed portion of the blood vessel.

[0014] As shown in FIGS. 1 to 3, the ultrasound diagnostic system 10 of this embodiment includes a robot device 20, a console device 90, and an ultrasound diagnostic device 100.

[0015] 1, the ultrasound diagnostic device 100 includes an ultrasound probe 101 and an ultrasound diagnostic device main body 110 connected to the ultrasound probe 101 via a cable 102. As shown in FIG. 3, the ultrasound diagnostic device main body 110 includes an ultrasound diagnosis control unit 111 that controls the entire device, an image processing unit 112 that processes signals received from the ultrasound probe 101 to generate ultrasound echo images, an image display unit 113 that displays the ultrasound echo images, and various operation switches (not shown).

[0016] The console device 90 is provided separately from the robot device 20, and instructs the robot device 20 to perform various operations and displays various information including the status of the robot device 20. The console device 90 includes a console control unit 91 that controls the entire device, an operation panel 92 that displays various information and can be touch-operated by an operator, a speaker 93, a communication unit 94 that communicates with the robot device 20, and an emergency stop switch 95. The emergency stop switch 95 is a switch for stopping the operation of the robot device 20 in the event of an emergency. Furthermore, a foot pedal 96 and a joint controller 97 are connected to the console device 90 via cables. The foot pedal 96 and the joint controller 97 are operation members that can issue various instructions.

[0017] As shown in Figures 1 to 3, the robot device 20 includes a base 25, a robot arm 21 installed on the base 25, a height adjustment mechanism 45 that manually adjusts the height of the robot arm 21, and a robot control device 80 (see Figure 3) that controls the robot arm 21.

[0018] 1 and 2, casters 26 with stoppers are attached to the four corners of the back surface of the base 25. The robot device 20 can be freely moved by the casters 26. In addition, locking portions 28 are provided at multiple locations (e.g., three locations) on the back surface of the base 25. These locking portions 28 protrude vertically downward when a lever 27 is pressed down, thereby locking (fixing) the robot device 20 so that it cannot move.

[0019] As shown in FIG. 1, the robot arm 21 includes a first arm 22, a second arm 23, a base 24, a first arm driving device 35, a second arm driving device 36, a position holding device 37, and a three-axis rotation mechanism 50.

[0020] The base end of the first arm 22 is connected to the base 24 via a first joint shaft 31 (hereinafter, sometimes referred to as the "joint shaft J2") extending in the vertical direction (Z-axis direction). The first arm driving device 35 includes a motor 35a, an encoder 35b, and an amplifier 35c. The rotation shaft of the motor 35a is connected to the first joint shaft 31 via a reducer (not shown). The first arm driving device 35 rotates (pivots) the first arm 22 along a horizontal plane (XY plane) around the first joint shaft 31 as a fulcrum by driving the first joint shaft 31 with the motor 35a. The encoder 35b is attached to the rotation shaft of the motor 35a and is configured as a rotary encoder that detects the amount of rotational displacement of the motor 35a. The amplifier 35c is a driving unit that drives the motor 35a by switching on and off a switching element.

[0021] The base end of the second arm 23 is connected to the tip end of the first arm 22 via a second joint shaft 32 (hereinafter sometimes referred to as the "joint shaft J3") extending in the vertical direction. The second arm driving device 36 includes a motor 36a, an encoder 36b, and an amplifier 36c. The rotation shaft of the motor 36a is connected to the second joint shaft 32 via a reducer (not shown). The second arm driving device 36 rotates (pivots) the second arm 23 along a horizontal plane around the second joint shaft 32 as a fulcrum by driving the second joint shaft 32 with the motor 36a. The encoder 36b is attached to the rotation shaft of the motor 36a and is configured as a rotary encoder that detects the amount of rotational displacement of the motor 36a. The amplifier 36c is a driving unit that drives the motor 35a by switching on and off a switching element.

[0022] The base 24 is movable up and down relative to the base 25 by an elevator device 40 installed on the base 25. As shown in FIGS. 1 and 2 , the elevator device 40 includes a first slider 41 fixed to the base 24, a first guide member 42 extending in the vertical direction to guide the movement of the first slider 41, a first ball screw shaft 43 (hereinafter sometimes referred to as the “elevation shaft J1”) extending in the vertical direction and threadedly engaging with a ball screw nut (not shown) fixed to the first slider 41, a motor 44 a that rotationally drives the first ball screw shaft 43, an encoder 44 b (see FIG. 3 ), and an amplifier 44 c that drives the motor 44 a. The elevator device 40 moves the base 24 fixed to the first slider 41 up and down along the first guide member 42 by rotationally driving the first ball screw shaft 43 with the motor 44 a. As a result, the robot arm 21 moves up and down along the elevator shaft J1. The encoder 44b is configured as a linear encoder that detects the vertical position (lifted position) of the first slider 41 (base 24).

[0023] 2 , the height adjustment mechanism 45 includes a second slider 46 fixed to the first guide member 42 of the lifting device 40, a second guide member 47 fixed to the base 25 and extending in the vertical direction to guide the movement of the second slider 46, a second ball screw shaft 48 (lifting shaft) extending in the vertical direction and threadedly engaging with a ball screw nut (not shown) fixed to the second slider 46, and an operation handle 49 connected to the second ball screw shaft 48 via a power transmission mechanism (bevel gear). The height adjustment mechanism 45 moves the first guide member 42 of the lifting device 40 fixed to the second slider 46 up and down along the second guide member 47 by manually operating the operation handle 49 to rotate the second ball screw shaft 48. The base end of the robot arm 21 is fixed to the base 24, and the base 24 is supported by the first guide member 42. Therefore, the height of the robot arm 21 can be adjusted by moving the first guide member 42 up and down using the height adjustment mechanism 45. This allows the height of the robot arm 21 to be adjusted according to the height of a bed on which a subject (patient) of ultrasound diagnosis lies, for example.

[0024] As shown in FIGS. 1 and 2 , the three-axis rotation mechanism 50 is connected to the tip of the second arm 23 via an attitude-maintaining shaft 33 (hereinafter sometimes referred to as the “joint shaft J4”) extending in the vertical direction. The three-axis rotation mechanism 50 includes a first rotation shaft 51 (hereinafter sometimes referred to as the “joint shaft J5”), a second rotation shaft 52 (hereinafter sometimes referred to as the “joint shaft J6”), and a third rotation shaft 53 (hereinafter sometimes referred to as the “joint shaft J7”) that are perpendicular to one another, a first rotation device 55 that rotates the first rotation shaft 51, a second rotation device 56 that rotates the second rotation shaft 52, and a third rotation device 57 that rotates the third rotation shaft 53. The first rotation shaft 51 is supported in an orthogonal orientation with respect to the attitude-maintaining shaft 33. The second rotation shaft 52 is supported in an orthogonal orientation with respect to the first rotation shaft 51. The third rotation shaft 53 is supported in an orthogonal orientation with respect to the second rotation shaft 52. The first rotation device 55 includes a motor 55a that rotates the first rotation shaft 51, an encoder 55b attached to the rotation shaft of the motor 55a and detecting the rotational displacement of the motor 55a, and an amplifier 55c that drives the motor 55a. The second rotation device 56 includes a motor 56a that rotates the second rotation shaft 52, an encoder 56b attached to the rotation shaft of the motor 56a and detecting the rotational displacement of the motor 56a, and an amplifier 56c that drives the motor 56a. The third rotation device 57 includes a motor 57a that rotates the third rotation shaft 53, an encoder 57b attached to the rotation shaft of the motor 57a and detecting the rotational displacement of the motor 57a, and an amplifier 57c that drives the motor 56a. The third rotation shaft 53 is provided with a holder 60 for holding the ultrasound probe 101.

[0025] The holder 60 holds the ultrasonic probe 101 so as to be positioned coaxially with the third rotation axis 53. In this embodiment, the holder 60 is provided with a switch 62 that permits manual operation when an operator manually operates the ultrasonic probe 101 while the ultrasonic probe 101 is held at the hand (holder 60) of the robot arm 21 in a teaching mode, which will be described later. This may be used as a direct teaching enable switch 62, and a function for stopping the robot arm 21 in an emergency may be added.

[0026] The robot device 20 of this embodiment can move the ultrasonic probe 101 to any position in any orientation within the movable area by combining translational motion in three directions, namely, the X-axis direction, the Y-axis direction, and the Z-axis direction, by the first arm driving device 35, the second arm driving device 36, and the lifting device 40, with rotational motion in three directions, namely, around the X-axis (pitching), around the Y-axis (rolling), and around the Z-axis (yawing), by the three-axis rotation mechanism 50.

[0027] The attitude holding device 37 holds the attitude of the three-axis rotation mechanism 50 (the orientation of the first rotation shaft 51) in a fixed direction regardless of the attitudes of the first arm 22 and the second arm 23. The attitude holding device 37 includes a motor 37a, an encoder 37b, and an amplifier 37c. The rotation shaft of the motor 37a is connected to the attitude holding shaft 33 via a reducer (not shown). The attitude holding device 37 sets a target rotation angle of the attitude holding shaft 33 based on the rotation angles of the first joint shaft 31 and the second joint shaft 32 so that the axial direction of the first rotation shaft 51 is always aligned in the left-right direction (X-axis direction), and drives and controls the motor 37a so that the attitude holding shaft 33 reaches the target rotation angle. This enables the translational motion in three directions and the rotational motion in three directions to be controlled independently, making control easier.

[0028] The force sensor 61 is attached to the tip of the robot arm 21 and detects the force components acting in the directions of the X-axis, Y-axis, and Z-axis as well as the torque components acting around each axis as external forces acting on the robot arm 21.

[0029] As shown in FIG. 3 , the robot control device 80 includes a robot control unit 81, a monitoring unit 82, an IO unit 83, a communication unit 84, and a storage unit 85. The robot control unit 81 is configured as a processor including a CPU, ROM, RAM, peripheral circuits, etc. The monitoring unit 82 is configured as a one-chip microcomputer including a CPU, ROM, RAM, peripheral circuits, etc. The monitoring unit 82 may also be duplicated. The robot control unit 81 performs various processes related to the control of the robot arm 21 (motors 35 a to 37 a, 44 a, 55 a to 57 a). The monitoring unit 82 monitors the status of each unit, such as the IO unit 83, the communication unit 84, and the sensor unit including amplifiers 35 c to 37 c, 44 c, 55 c to 57 c, and encoders 35 b to 37 b, 44 b, 55 b to 57 b. The IO unit 83 is an I / O port that inputs a detection signal from the direct teaching enable switch 62 and inputs and outputs signals from external devices. The communication unit 84 communicates between the robot control device 80 and the console device 90 via wired or wireless connections, exchanging various control signals and data between them.

[0030] Each of the amplifiers 35c to 37c, 44c, and 55c to 57c includes a motor control unit 71, a drive power supply unit 72, and an IO unit 73. The motor control unit 71 has switching elements and controls the motors 35a to 37a, 44a, and 55a to 57a by controlling the switching of the switching elements based on feedback signals from the encoders 35b to 37b, 44b, and 55b to 57b, etc. The drive power supply unit 72 supplies the power necessary to drive the motors 35a to 37a, 44a, and 55a to 57a. The IO unit 83 is an I / O port that inputs various signals such as position signals from the encoders 35b to 37b, 44b, and 55b to 57b, current signals from current sensors that detect the current flowing through each of the motors 35a to 37a, 44a, and 55a to 57a, and command signals (control signals) from the robot control unit 81 to each of the motors 35a to 37a, 44a, and 55a to 57a.

[0031] Next, a description will be given of the operation of the robot device 20 included in the thus configured ultrasound diagnostic system 10. The robot device 20 of this embodiment has two operation modes: a direct teaching mode and an automatic operation mode.

[0032] The direct teaching mode is a mode in which an operator can register the position and orientation of the ultrasonic probe 101 at any multiple points while grasping and manually operating the tip (holding unit 60) of the robot arm 21 holding the ultrasonic probe 101. In the direct teaching mode, the robot control unit 81 (CPU) acquires the elevation position Z1 of the elevator shaft J1 and the rotation angles θ2 to θ7 of the joint axes J2 to J7 from the encoders 35b to 37b, 44b, and 55b to 57b based on a registration instruction from the operator. Next, the robot control unit 81 calculates the position and orientation of the tip of the robot arm 21, i.e., the position and orientation of the ultrasonic probe 101, by forward kinematics based on the acquired elevation position Z1 of the elevator shaft J1 and the rotation angles θ2 to θ7 of the joint axes J2 to J7. The robot control unit 81 then associates the acquired elevation position Z1 and rotation angles θ2 to θ7 with the calculated position and orientation of the ultrasonic probe 101 and stores them in the memory unit 85 as registration points. The operator can issue a registration instruction by, for example, stepping on the foot pedal 96, operating the operation panel 92, or operating using voice recognition.

[0033] Here, a movable area is defined for the robot device 20. In the direct teaching mode, when the hand (ultrasonic probe 101) of the robot arm 21 approaches the boundary of the movable area, the motors 35a to 37a, 44a, and 55a to 57a are controlled so that a load (resistance) is applied in the direction opposite to the direction of operation of the robot arm 21 by the operator. This prevents the hand of the robot arm 21 from being operated beyond the movable area. The operation direction of the robot arm 21 can be determined based on the detection signal from the force sensor 61 and the detection signals from the encoders 35b to 37b, 44b, and 55b to 57b.

[0034] The automatic operation mode is a mode in which the robot device 20 automatically moves the ultrasonic probe 101 so that it passes through the multiple points registered in the direct teaching mode in a predetermined order. In the automatic operation mode, when the operator instructs the robot control unit 81 to start diagnosis, the robot control unit 81 moves the ultrasonic probe 101 to the first point among the multiple points registered in advance. The ultrasonic probe 101 is moved by setting the elevation position of the elevator shaft J1 of the robot arm 21 and the rotation angles of the joint shafts J2 to J7 of the robot arm 21 corresponding to the point to be moved (the position and posture of the hand of the robot arm 21) as a target elevation position Z1tag and target rotation angles θ2tag to θ7tag, and controlling the motors 35a to 37a, 44a, and 55a to 57a so that the elevation position Z1 of the elevator shaft J1 and the rotation angles θ2 to θ7 of the joint shafts J2 to J7 detected by the encoders 35b to 37b, 44b, and 55b to 57b match the corresponding target elevation position Z1tag and target rotation angles θ2tag to θ7tag. When the operator performs a forward operation, the robot control unit 81 moves the ultrasonic probe 101 to the next point. On the other hand, when the operator performs a backward operation, the robot control unit 81 moves the ultrasonic probe 101 to the previous point. The forward and backward operations can be performed by, for example, stepping on the foot pedal 96, operating the operation panel 92, or operating by voice recognition.

[0035] In the automatic operation mode, the points (movement trajectory) registered in the direct teaching mode are displayed in three dimensions on the operation panel 92 of the console device 90, as shown in Fig. 4. When moving the ultrasonic probe 101 to the robot device 20, the operator can check the destination of the ultrasonic probe 101 in advance on the operation panel 92.

[0036] When applying ultrasonic diagnosis to catheter treatment, if the operator pre-teaches the scanning direction of the ultrasonic probe 101 to coincide with the central axis direction (length direction) of the patient's blood vessel, the operator can execute the automatic operation mode to automatically move the ultrasonic probe 101 in the central axis direction of the blood vessel simply by operating the foot pedal 96. This allows the operator to operate the ultrasonic probe 101 by himself and advance the guidewire while checking the position of the patient's blood vessel from the ultrasonic echo image.

[0037] As described above, since the robot device 20 of this embodiment is expected to work in the same space as a worker, there is a possibility of collision with another object (worker). For this reason, the robot device 20 of this embodiment determines whether or not there is a collision between the robot arm 21 (including the ultrasonic probe 101) and another object, and if it determines that there has been a collision with the other object, it transitions to a safe state in which the robot arm 21 is retracted from the object.

[0038] 5 is a flowchart showing an example of a collision determination process executed by the robot control unit 81 of the robot control device 80. This process is repeatedly executed at predetermined time intervals (for example, every few msec or every tens of msec).

[0039] When the collision detection process is executed, the robot control unit 81 first determines whether the current state of the robot device 20 is a normal state (S100). If the robot control unit 81 determines that the current state is not a normal state but a safe state, it terminates the collision detection process. On the other hand, if the robot control unit 81 determines that the current state is a normal state, it inputs the elevation position Z1 of the elevation shaft J1 and the rotation angles θ2 to θ7 of the joint shafts J2 to J7 from the encoders 35b to 37b, 44b, and 55b to 57b (S110), calculates the elevation speed V1 based on the input elevation position Z1, and calculates the angular velocities ω2 to ω7 based on the input rotation angles θ2 to θ7 (S120). Then, the robot control unit 81 determines whether the elevation position Z1 is greater than a threshold value Z1ref and whether the angular velocities ω2 to ω7 are greater than the corresponding threshold values ​​ω2ref to ω7ref (S130). Here, the thresholds Z1ref and ω2ref to ω7ref are thresholds for determining whether the displacement of the robot arm 21 is due to a collision with another object, and are usually set to speeds slightly higher than the upper limit of the speed range of the lifting speed of the lifting axis J1 and the angular velocities of the joint axes J2 to J7 when operating the robot arm 21. When the robot control unit 81 determines that the lifting speed V1 is equal to or lower than the threshold V1ref and that all of the angular velocities ω2 to ω7 are equal to or lower than the corresponding thresholds ω2ref to ω7ref, it determines that no collision with another object has occurred and ends the collision determination process.

[0040] On the other hand, if the robot control unit 81 determines that the elevation velocity V1 is greater than the threshold value V1ref or that any of the angular velocities ω2 to ω7 are greater than the corresponding threshold values ​​ω2ref to ω7ref, it determines that a collision with another object has occurred (S140). Next, the robot control unit 81 calculates the hand position P (position of the ultrasound probe 101) of the robot arm 21 using forward kinematics based on the elevation position Z1 of the elevation axis J1 and the rotation angles θ2 to θ7 of the joint axes J2 to J7 input in S110 (S150), and updates the restricted area based on the calculated hand position P (S160). The robot control unit 81 then transitions to a safe state (S170) and ends the collision detection process.

[0041] The restricted area is an area of ​​the movable area where the movement of the robot arm 21 is restricted. When the ultrasound probe 101 is pressed against the surface of a patient's thigh for ultrasound diagnosis, the restricted area is the portion of the thigh. In this embodiment, the restricted area is initially set as a circular (sector-shaped) area in a cross-sectional view of the thigh, as shown in FIG. 6 , with a predetermined position O as the thigh center and surrounded by the maximum expected radius of the thigh (the maximum expected thigh radius). Then, when it is determined that the robot arm 21 has collided with another object (patient), the restricted area is updated (changed) in S160 to a circular (sector-shaped) area whose radius (the collision position radius) is the distance between the hand position P (the position of the ultrasound probe 101) at the time of collision and the predetermined position O. Note that the shape of the restricted area is not limited to a circular (sector-shaped) shape in a cross-sectional view of the thigh, and may be an ellipse, an egg shape, or the like. The restricted area may also be set to a cylindrical or tapered shape in the depth direction of FIG. 6 . The operation of the robot device 20 when the tip (ultrasonic probe 101) of the robot arm 21 enters the restricted area in the safe state will be described later.

[0042] Next, the operation of the robot device 20 in the safe state will be described. Fig. 7 is a flowchart showing an example of safety processing executed by the robot control unit 81. This processing is repeatedly executed at predetermined time intervals (for example, every few msec or every tens of msec) from when the robot device 20 transitions to the safe state until the safe state ends.

[0043] When safety processing is executed, the robot control unit 81 first inputs the elevation position Z1 of the elevation shaft J1 and the rotation angles θ2 to θ7 of the joint shafts J2 to J7 from the encoders 35b to 37b, 44b, and 55b to 57b (S200), and calculates the hand position P, the retraction distance L, and the retraction velocity V (S210). The calculation of the hand position P has been described above. The retraction distance L is the cumulative movement amount of the hand position P since the transition to the safe state, and can be calculated by adding up the distance between the currently calculated hand position P and the previously calculated hand position. The retraction velocity V can be calculated by dividing the distance between the currently calculated hand position P and the previously calculated hand position by the execution time interval of the safety processing.

[0044] Next, the robot control unit 81 determines whether the hand position P is within the restricted area (S220), whether the retraction distance L exceeds a threshold Lref (S230), whether the retraction speed V exceeds a threshold Vref (S240), and whether a predetermined time has elapsed since the transition to the safe state (S250). If the robot control unit 81 determines that the hand position P is not within the restricted area, the retraction distance L is equal to or less than the threshold Lref, the retraction speed V is equal to or less than the threshold Vref, and the predetermined time has not elapsed since the transition to the safe state, it calculates the lifting speed V1 based on the lifting position Z1 input in S200 and calculates the angular velocities ω2 to ω7 based on the rotation angles θ2 to θ7 input in S200 (S260). Next, the robot control unit 81 sets a compensation torque Tc1 for the lift shaft J1 based on the calculated lift speed V1, and sets compensation torques Tc2 to Tc7 for the joint shafts J2 to J7 based on the calculated angular velocities ω2 to ω7 (S270). Next, the robot control unit 81 sets a torque command for the lift shaft Z1 obtained by adding the compensation torque Tc1 to the original torque to be output to the lift shaft Z1, and sets a torque command for each joint shaft J2 to J7 obtained by adding the compensation torques Tc2 to Tc7 to the original torque to be output to each joint shaft J2 to J7 (S280). Then, the robot control unit 81 controls the motors 35a to 37a, 44a, 55a to 57a so that torques corresponding to the set torque commands are output (S290), and the safety process ends.

[0045] In the safe state, when the robot arm 21 moves along the lift axis Z1 due to a reaction force from a collision with another object, a torque corresponding to (proportional to) the lift velocity V1 is output in the direction of movement. Furthermore, when the robot arm 21 rotates around the joint axes J2 to J7 due to a reaction force from a collision with another object, a torque corresponding to (proportional to) the angular velocities ω2 to ω7 is output in the direction of rotation. FIG. 8 is an explanatory diagram showing the compensation torques of the lift axis J1 and each joint axis J2 to J7 set in the normal state and the safe state. In the safe state, the compensation torques Tc1 to Tc7 include compensation torque for static friction (static friction compensation) and compensation torque for viscous friction (viscous friction compensation). The torque corresponding to the lift velocity V1 and angular velocities ω2 to ω7 is added to the viscous friction compensation term. The compensation torques of the lift axis J1 and the joint axes J5 to J7 include compensation torque (gravity compensation) in a direction that cancels out the load torque due to their own weight, both in the normal state and the safe state. The joint axes J2 to J4 have axial directions extending vertically, so gravity compensation is not required.

[0046] By performing such safety processing, the robot device 20 can retract the robot arm 21 that has collided with an object (worker) in a direction away from the object. As a result, the pressing force of the robot arm 21 can be quickly alleviated, and the safety of the worker can be fully ensured. Furthermore, the retraction operation of the robot arm 21 is performed by a torque corresponding to the external force acting on the robot arm 21. Therefore, once the external force is no longer applied to the robot arm 21, the torque corresponding to the external force is not output. This allows the robot device 20 to retract the robot arm 21 by the amount necessary to alleviate the pressing force, thereby preventing secondary damage, such as a collision with another object, during the retraction operation.

[0047] When the robot control unit 81 determines in S220 that the hand position P is within the restricted area, determines in S230 that the retraction distance L exceeds the threshold Lref, determines in S240 that the retraction speed V exceeds the threshold Vref, or determines in S250 that a predetermined time has elapsed since transitioning to the safe state, the robot control unit 81 ends the safe state (S300) and terminates the safety processing. Specifically, the robot control unit 81 controls the motors 35a to 37a, 44a, and 55a to 57a so that the retraction operation of the robot arm 21 is stopped. This makes it possible to avoid unexpected operations during the retraction operation of the robot arm 21 and suppress the occurrence of secondary damage.

[0048] Here, the correspondence between the main elements of the embodiment and the main elements of the present disclosure described in the claims will be described. That is, in this embodiment, the robot arm 21 corresponds to the robot main body, the motors 35a to 37a, 44a, and 55a to 57a correspond to the drive unit, the encoders 35b to 37b, 44b, and 55b to 57b correspond to the external force detection unit, and the robot control unit 81 corresponds to the control unit. The encoders 35b to 37b, 44b, and 55b to 57b also correspond to the position detection unit. Furthermore, the ultrasonic probe 101 corresponds to the ultrasonic probe.

[0049] It goes without saying that the present disclosure is not limited to the above-described embodiments, and can be implemented in various forms as long as they fall within the technical scope of the present disclosure.

[0050] For example, in the above-described embodiment, the robot device 20 detects an external force acting on the robot arm 21 due to a collision with another object by determining whether the elevation velocity V1 of the elevation axis J1 and the angular velocities ω2 to ω7 of the joint axes J2 to J7 are greater than the corresponding thresholds Z1ref and ω2ref to ω7ref. However, the robot device 20 may also detect an external force acting on the robot arm 21 due to a collision with another object by detecting the torque acting on the elevation axis J1 and the joint axes J2 to J7 using a torque sensor. In this case, the robot control unit 81 may set a compensation torque corresponding to (proportional to) the detected torque in the direction of the detected torque. Alternatively, the robot device 20 may directly detect an external force acting on the robot arm 21 using the force sensor 61. In this case, the force sensor 61 detects force components acting in the X-, Y-, and Z-axis directions and torque components acting around each axis as the external force acting on the robot arm 21. Therefore, the robot control unit 81 can use a transformation matrix to convert the force components and torque components detected by the force sensor 61 into torques for the elevator axis J1 and each of the joint axes J2 to J7, and set the compensation torques.

[0051] In the above-described embodiment, the robot control unit 81 controls the motors 35a to 37a, 44a, and 55a to 57a so that the robot arm 21 retracts in the direction of an external force acting on the robot arm 21 due to a collision with another object (the direction of the lifting / lowering velocity V1 or the angular velocities ω2 to ω7). However, the robot control unit 81 may set the direction of the retraction movement of the robot arm 21 to the opposite direction to the direction of the movement of the robot arm 21 at the time of the collision (the lifting / lowering direction of the lifting axis J1 and the rotational direction of the joint axes J2 to J7).

[0052] In the above-described embodiment, the robot device 20 is configured as a seven-axis articulated robot capable of translational movement in three directions and rotational movement in three directions. However, the number of axes may be any number. The robot device 20 may also be configured as a so-called vertical articulated robot, horizontal articulated robot, or the like.

[0053] As described above, when an external force acting on the robot body due to contact with an object is detected, the robot device of the present disclosure controls the drive unit to cause the robot body to retreat in a predetermined direction. This makes it possible to reduce the pushing force of the robot body when the robot body collides with an object, thereby further improving the safety of workers, etc.

[0054] In the robot device according to the present disclosure, the control unit may control the drive unit to, as the safe state, perform a retreat operation with a greater drive force as the detected external force increases. In this way, when the robot body collides with another object (worker), the pushing force of the robot body can be reduced by a necessary amount, thereby further improving the safety of the worker, etc.

[0055] In the robot device according to the present disclosure, the control unit may control the drive unit to cause the robot body to perform a retreat operation in the direction of the detected external force as the safe state. This allows the retreat direction of the robot body to be appropriately determined by simple processing.

[0056] Furthermore, the robot device of the present disclosure may further include a position detection unit that detects the position of the robot body, the robot body being a medical robot used for diagnosing and treating patients, the control unit controlling the drive unit to operate the robot body based on the expected position of the patient's thigh, and changing the position of the thigh based on the position of the robot body detected by the position detection unit when an external force acting on the robot body is detected. In this way, when performing work on a patient's thigh, the position of the thigh, which varies from person to person, can be appropriately grasped.

[0057] In the robot device disclosed herein, the control unit may terminate the retraction operation when, in the safe state, the retraction operation causes the robot main body to enter a restricted area set within the movable area. This can avoid unexpected movements during the retraction operation and suppress secondary damage. In this case, the robot device may include a position detection unit that detects the position of the robot main body, and the control unit may set the restricted area as a predetermined range whose boundary is the position of the robot main body detected by the position detection unit when the external force detection unit detects an external force acting on the robot main body. This allows the restricted area to be set appropriately.

[0058] In the robot device of the present disclosure, the control unit may terminate the retraction operation when a predetermined time has elapsed since the robot device entered the safe state, when the movement amount of the robot body during the retraction operation in the safe state exceeds a predetermined amount, or when the movement speed of the robot body during the retraction operation in the safe state exceeds a predetermined speed. In this way, unexpected operations can be avoided during the retraction operation, and the occurrence of secondary damage can be suppressed.

[0059] In the robot device of the present disclosure, the robot body may have an arm, the drive unit may have a motor that drives a joint shaft of the arm, the external force detection unit may detect an angular velocity of the joint shaft or a torque acting on the joint shaft as an external force acting on the robot body, and the control unit may control the drive unit so that, in the safe state, an additional torque corresponding to the detected angular velocity or torque is output from the corresponding motor in the direction of the detected angular velocity or torque. This allows for appropriate retraction operations.

[0060] Alternatively, in the robot device of the present disclosure, the robot main body may have an arm, the drive unit may have a motor that drives a joint axis of the arm, the external force detection unit may have a force sensor provided on the arm, and the control unit may control the drive unit so that, in the safe state, an additional torque corresponding to a detection value of the force sensor is output from the corresponding motor in the direction of the detected external force. In this way, the retraction operation can be performed appropriately.

[0061] The present disclosure is not limited to the form of a robot device, but can also be in the form of an ultrasound diagnostic system.

[0062] The present disclosure is applicable to industries such as the manufacturing of robotic devices and ultrasound diagnostic systems.

[0063] 10 Ultrasound diagnostic system, 20 Robot device, 21 Robot arm, 22 First arm, 23 Second arm, 24 Base, 25 Base, 26 Caster, 27 Lever, 28 Locking part, 31 First joint axis, 32 Second joint axis, 33 Attitude holding axis, 35 First arm driving device, 35a Motor, 35b Encoder, 35c Amplifier, 36 Second arm driving device, 36a Motor, 36b Encoder, 36c Amplifier, 37 Attitude holding device, 37a Motor, 37b Encoder, 37c Amplifier, 40 Elevating device, 41 First slider, 42 First guide member, 43 First ball screw shaft, 44a Motor, 44b Encoder, 44c Amplifier, 45 Height adjustment mechanism, 46 Second slider, 47 Second guide member, 48 Second ball screw shaft, 49 Operating handle, 50 3-axis rotating mechanism, 51 first rotating axis, 52 second rotating axis, 53 third rotating axis, 55 first rotating device, 55a motor, 55b encoder, 55c amplifier, 56 second rotating device, 56a motor, 56b encoder, 56c amplifier, 57 third rotating device 57a motor 57b encoder, 57c amplifier, 60 holding unit, 61 force sensor, 62 switch, 71 motor control unit, 72 drive power supply unit, 73 IO unit, 80 robot control device, 81 robot control unit, 82 monitoring unit, 83 IO unit, 84 communication unit, 85 memory unit, 90 console device, 91 console control unit, 92 operation panel, 93 speaker, 94 communication unit, 95 emergency stop switch, 96 foot pedal, 97 joint controller, 100 ultrasound diagnostic device, 101 ultrasound probe, 102 Cable, 110 ultrasound diagnostic device main body, 111 ultrasound diagnostic control unit, 112 image processing unit, 113 image display unit, J1 lift axis, J2, J3, J4, J5, J6, J7 joint axes.

Claims

1. The robot body, A drive unit that drives the robot body; an external force detection unit that detects an external force acting on the robot body; a control unit that transitions to a safe state by controlling the drive unit when an external force acting on the robot body is detected by the external force detection unit so that the robot body performs an escape operation in a predetermined direction; A robot device comprising:

2. The robot device according to claim 1 , the control unit controls the drive unit so that, as the detected external force is greater, the robot body performs an evacuation operation with a greater drive force as the safe state. Robot device.

3. The robot device according to claim 1 , the control unit controls the drive unit so that, as the safe state, the robot body performs an escape operation in a direction of the detected external force. Robot device.

4. The robot device according to any one of claims 1 to 3, a position detection unit for detecting a position of the robot main body, The robot body is a robot body of a medical robot used for diagnosing or treating a patient, the control unit controls the drive unit so that the robot body operates based on an assumed thigh position of the patient, and changes the thigh position based on the position of the robot body detected by the position detection unit when an external force acting on the robot body is detected. Robot device.

5. The robot device according to any one of claims 1 to 3, the control unit, when the robot body enters a restricted area set within a movable area as a result of the evacuation operation in the safe state, ends the evacuation operation. Robot device.

6. The robot device according to claim 5, a position detection unit for detecting a position of the robot main body, the control unit sets the restricted area to a predetermined range having a boundary defined by a position of the robot main body detected by the position detection unit when an external force acting on the robot main body is detected by the external force detection unit. Robot device.

7. The robot device according to any one of claims 1 to 3, the control unit terminates the evacuation operation when a predetermined time has elapsed since transition to the safe state, when a movement amount in the evacuation operation of the robot body in the safe state exceeds a predetermined amount, or when a movement speed in the evacuation operation of the robot body in the safe state exceeds a predetermined speed. Robot device.

8. The robot device according to any one of claims 1 to 3, The robot body has an arm, the drive unit has a motor that drives a joint shaft of the arm, the external force detection unit detects an angular velocity of the joint shaft or a torque acting on the joint shaft as an external force acting on the robot main body, The control unit controls the drive unit so that, in the safe state, an additional torque corresponding to the detected angular velocity or torque is output from a corresponding motor in a direction of the detected angular velocity or torque. Robot device.

9. The robot device according to any one of claims 1 to 3, The robot body has an arm, the drive unit has a motor that drives a joint shaft of the arm, the external force detection unit has a force sensor provided on the arm, the control unit controls the drive unit so that, in the safe state, an additional torque corresponding to the detection value of the force sensor is output from a corresponding motor in a direction of the detected external force. Robot device.

10. An ultrasonic probe; a robot body that holds the ultrasonic probe at its hand; A drive unit that drives the robot body; an external force detection unit that detects an external force acting on the robot body; a control unit that transitions to a safe state by controlling the drive unit when an external force acting on the robot body is detected by the external force detection unit so that the robot body performs an escape operation in a predetermined direction; An ultrasound diagnostic system comprising: