Robotic devices and ultrasound diagnostic systems

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

Technical Field

[0001] This specification discloses a robot device and an ultrasonic diagnostic system.

Background Art

[0002] Conventionally, as this type of robot device, there has been proposed one including a collision detection unit that detects that the robot has collided with an object, a first control unit that executes deceleration control to drive each motor of the robot to decelerate when it is detected that the robot has collided with an object, and a second control unit that, after the deceleration control is executed, stops the power supply to each motor and executes dynamic braking for a predetermined time to short-circuit between the power input / output terminals in each motor (see, for example, Patent Document 1). In this robot device, when the robot collides with an object, the robot can be quickly decelerated, and it is possible to prevent an operator from being injured. Further, while the dynamic braking is being executed, the operator can push and move the robot or move away from the robot.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described robot device, when the robot collides with an operator, just decelerating each motor of the robot or executing dynamic braking is not enough to eliminate the force (pushing force) applied from the robot to the operator, and there are cases where the safety of the operator cannot be sufficiently ensured.

[0005] The primary objective of this disclosure is to provide a robotic device or an ultrasonic diagnostic system equipped with a robotic device that can enhance safety against collisions between the robot and objects. [Means for solving the problem]

[0006] This disclosure employs the following means to achieve the primary objectives described above.

[0007] The robotic device described herein is The robot body and The drive unit that drives the robot body, An external force detection unit for detecting external forces acting on the robot body, When the external force detection unit detects an external force acting on the robot body, the control unit transitions to a safety state in which it controls the drive unit so that the robot body moves to a retraction position in a predetermined direction. The gist of it is that it is equipped with the following features.

[0008] The robotic device of this disclosure controls the drive unit so that the robot body retracts in a predetermined direction when an external force acting on the robot body due to contact with an object is detected. This makes it possible to mitigate the pushing force of the robot body when it collides with an object, thereby further enhancing the safety of workers and others.

[0009] The ultrasound diagnostic system of this disclosure comprises an ultrasound probe and a robotic device of this disclosure that holds the ultrasound probe at its end, and can therefore achieve the same effects as the robotic device of this disclosure. [Brief explanation of the drawing]

[0010] [Figure 1] This is an external perspective view of the ultrasound diagnostic system including the robotic device of this embodiment. [Figure 2] This is a side view of the robotic device. [Figure 3] This is a block diagram showing the electrical connection between a robotic device and an ultrasound diagnostic device. [Figure 4] This is an explanatory diagram showing the movement trajectory of an ultrasound probe. [Figure 5] This flowchart shows an example of collision detection processing. [Figure 6] This is an explanatory diagram describing the restricted area. [Figure 7] This flowchart shows an example of a safety procedure. [Figure 8] This is an explanatory diagram showing the compensation torques for the lifting axis J1 and each joint axis J2 to J7, which are set for the normal state and the safety state, respectively. [Modes for carrying out the invention]

[0011] Next, the forms for implementing this disclosure will be described with reference to the drawings.

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

[0013] The ultrasound diagnostic system 10 of this embodiment acquires ultrasound echo images by holding an ultrasound probe 101 at the end of a robotic arm 21 and operating the robotic device 20 so that the ultrasound probe 101 is pressed against the patient's body surface. This ultrasound diagnostic system 10 is used, for example, in catheter treatment. The operator (surgeon) who is operating the catheter guidewire can press the ultrasound probe 101 against the surface of the patient's thigh and advance the guidewire while recognizing the positional relationship between the tip of the guidewire and the blood vessel from the obtained ultrasound echo image, thereby accurately passing the guidewire through the center of the occluded or narrowed area of ​​the blood vessel.

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

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

[0016] The console device 90 is provided separately from the robot device 20, and instructs various operations of the robot device 20 and displays various information including the state of the robot device 20. The console device 90 includes a console control unit 91 that controls the entire apparatus, an operation panel 92 that displays various information and can be touched and 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 an emergency. Further, the console device 90 has a foot pedal 96 and a joint controller 97 connected via a cable. The foot pedal 96 and the joint controller 97 are operation members capable of giving various instructions.

[0017] As shown in FIGS. 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 for manually adjusting the height of the robot arm 21, and a robot control device 80 (see FIG. 3) for controlling the robot arm 21.

[0018] As shown in FIGS. 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. Further, a locking portion 28 is provided at a plurality of locations (for example, three locations) on the back surface of the base 25, which projects vertically downward by pushing down a lever 27 to lock (fix) 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, an attitude holding device 37, and a rotating three-axis mechanism 50.

[0020] The base end portion of the first arm 22 is connected to the base 24 via a first joint axis 31 (hereinafter, may be referred to as "joint axis 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 rotating shaft of the motor 35a is connected to the first joint axis 31 via a speed reducer (not shown). The first arm driving device 35 rotates the first joint axis 31 by the motor 35a to rotate (swing) the first arm 22 along the horizontal plane (XY plane) with the first joint axis 31 as a fulcrum. The encoder 35b is attached to the rotating shaft of the motor 35a and is configured as a rotary encoder that detects the rotational displacement amount of the motor 35a. The amplifier 35c is a driving unit for driving the motor 35a by switching of switching elements.

[0021] The base end portion of the second arm 23 is connected to the tip end portion of the first arm 22 via a second joint axis 32 (hereinafter, may be referred to as "joint axis J3") extending in the vertical direction. The second arm driving device 36 includes a motor 36a, an encoder 36b, and an amplifier 36c. The rotating shaft of the motor 36a is connected to the second joint axis 32 via a speed reducer (not shown). The second arm driving device 36 rotates the second joint axis 32 by the motor 36a to rotate (swing) the second arm 23 along the horizontal plane with the second joint axis 32 as a fulcrum. The encoder 36b is attached to the rotating shaft of the motor 36a and is configured as a rotary encoder that detects the rotational displacement amount of the motor 36a. The amplifier 36c is a driving unit for driving the motor 35a by switching of switching elements.

[0022] The base 24 is provided so as to be able to move up and down relative to the base 25 by a lifting device 40 installed on the base 25. As shown in Figures 1 and 2, the lifting 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 "lifting shaft J1") extending in the vertical direction and into which a ball screw nut (not shown) fixed to the first slider 41 is screwed, a motor 44a that rotationally drives the first ball screw shaft 43, an encoder 44b (see Figure 3), and an amplifier 44c that drives the motor 44a. The lifting device 40 rotates the first ball screw shaft 43 with the motor 44a, thereby moving the base 24 fixed to the first slider 41 up and down along the first guide member 42. As a result, the robot arm 21 moves up and down along the lifting shaft J1. The encoder 44b is configured as a linear encoder that detects the vertical position (up / down position) of the first slider 41 (base 24).

[0023] As shown in Figure 2, the height adjustment mechanism 45 includes a second slider 46 fixed to a first guide member 42 of the lifting device 40, a second guide member 47 fixed to the base 25 and extending vertically to guide the movement of the second slider 46, a second ball screw shaft 48 (lifting shaft) extending vertically and into which a ball screw nut (not shown) fixed to the second slider 46 is screwed, and an operating handle 49 connected to the second ball screw shaft 48 via a power transmission mechanism (bevel gear). The height adjustment mechanism 45 rotates the second ball screw shaft 48 by manually operating the operating handle 49, thereby moving the first guide member 42 of the lifting device 40, which is fixed to the second slider 46, up and down along the second guide member 47. The base 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, for example, the height of the robot arm 21 to be adjusted according to the height of the bed on which the subject (patient) of the ultrasound diagnosis lies.

[0024] As shown in Figures 1 and 2, the three-axis rotating mechanism 50 is connected to the tip of the second arm 23 via a vertically extending posture-holding shaft 33 (hereinafter sometimes referred to as "joint shaft J4"). The three-axis rotating mechanism 50 comprises a first rotation axis 51 (hereinafter sometimes referred to as "joint shaft J5"), a second rotation axis 52 (hereinafter sometimes referred to as "joint shaft J6"), and a third rotation axis 53 (hereinafter sometimes referred to as "joint shaft J7"), all of which are orthogonal to each other, a first rotation device 55 for rotating the first rotation axis 51, a second rotation device 56 for rotating the second rotation axis 52, and a third rotation device 57 for rotating the third rotation axis 53. The first rotation axis 51 is supported in a posture orthogonal to the posture-holding shaft 33. The second rotation axis 52 is supported in a posture orthogonal to the first rotation axis 51. The third rotation axis 53 is supported in a posture orthogonal to the second rotation axis 52. The first rotating device 55 includes a motor 55a that rotates the first rotating shaft 51, an encoder 55b attached to the rotating shaft of the motor 55a to detect the rotational displacement of the motor 55a, and an amplifier 55c that drives the motor 55a. The second rotating device 56 includes a motor 56a that rotates the second rotating shaft 52, an encoder 56b attached to the rotating shaft of the motor 56a to detect the rotational displacement of the motor 56a, and an amplifier 56c that drives the motor 56a. The third rotating device 57 includes a motor 57a that rotates the third rotating shaft 53, an encoder 57b attached to the rotating shaft of the motor 57a to detect the rotational displacement of the motor 57a, and an amplifier 57c that drives the motor 56a. The third rotating shaft 53 is also provided with a holding part 60 for holding the ultrasonic probe 101.

[0025] The holding unit 60 holds the ultrasonic probe 101 so as to be coaxial with the third rotation axis 53. In this embodiment, the holding unit 60 is provided with a switch 62 that allows manual operation when an operator manually operates the ultrasonic probe 101 while the ultrasonic probe 101 is held by the end-effector (holding unit 60) of the robot arm 21 in the teaching mode described later. This may be designated as a direct teaching enable switch 62, and a function to stop 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 posture within the movable area by combining translational motion in three directions (X-axis, Y-axis, and Z-axis) by the first arm drive device 35, the second arm drive device 36, and the lifting device 40, and rotational motion in three directions (pitching around the X-axis, rolling around the Y-axis, and yawing around the Z-axis) by the three-axis rotation mechanism 50.

[0027] The attitude holding device 37 maintains the attitude of the three-axis rotation mechanism 50 (the orientation of the first rotation axis 51) in a constant orientation, regardless of the orientation of the first arm 22 and the second arm 23. The attitude holding device 37 comprises a motor 37a, an encoder 37b, and an amplifier 37c. The rotation axis of the motor 37a is connected to the attitude holding axis 33 via a reduction gear (not shown). The attitude holding device 37 sets a target rotation angle of the attitude holding axis 33 based on the rotation angle of the first joint axis 31 and the rotation angle of the second joint axis 32, so that the axial direction of the first rotation axis 51 is always in the left-right direction (X-axis direction), and drives and controls the motor 37a so that the attitude holding axis 33 reaches the target rotation angle. This makes it possible to control the translational motion in three directions and the rotational motion in three directions independently, making control easier.

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

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

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

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

[0032] The direct teaching mode allows the operator to manually operate the end-effector (holding part 60) of the robot arm 21 holding the ultrasonic probe 101, and register the position and orientation of the ultrasonic probe 101 at any number of points. In direct teaching mode, the robot control unit 81 (CPU) acquires the lifting position Z1 of the lifting axis J1 and the rotation angles θ2 to θ7 of the joint axes J2 to J7 from each encoder 35b to 37b, 44b, and 55b to 57b based on the registration instructions from the operator. Subsequently, the robot control unit 81 calculates the position and orientation of the end-effector of the robot arm 21, i.e., the position and orientation of the ultrasonic probe 101, using forward kinematics based on the acquired lifting position Z1 of the lifting axis J1 and the rotation angles θ2 to θ7 of the joint axes J2 to J7. Then, the robot control unit 81 stores the acquired lifting position Z1 and rotation angles θ2 to θ7 and the calculated position and orientation of the ultrasonic probe 101 as registration points in the storage unit 85. Operator registration instructions can be given, for example, by pressing the foot pedal 96, operating the control panel 92, or by voice recognition.

[0033] Here, the robot device 20 has a defined movable area. In direct teaching mode, when the end effector (ultrasonic probe 101) of the robot arm 21 approaches the boundary of the movable area, the motors 35a~37a, 44a, 55a~57a are controlled so that a load (resistance) is applied in the opposite direction to the direction of operation of the robot arm 21 by the operator. This prevents the end effector of the robot arm 21 from being operated beyond the movable area. The direction of operation of the robot arm 21 can be determined based on detection signals from the force sensor 61 and from the encoders 35b~37b, 44b, 55b~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 a predetermined sequence of points registered by the direct teaching mode. In automatic operation mode, when the operator instructs the robot control unit 81 to start the diagnosis, it moves the ultrasonic probe 101 to the first of the pre-registered points. The movement of the ultrasonic probe 101 is performed by setting the lifting position of the lifting axis J1 and the rotation angles of the joint axes J2 to J7 of the robot arm 21 corresponding to the point to be moved (the position and orientation of the end effector of the robot arm 21) to target lifting position Z1tag and target rotation angles θ2tag to θ7tag, and controlling each motor 35a to 37a, 44a, 55a to 57a so that the lifting position Z1 of the lifting axis J1 and the rotation angles θ2 to θ7 of the joint axes J2 to J7 detected by each encoder 35b to 37b, 44b, 55b to 57b match the corresponding target lifting position Z1tag and target rotation angles θ2tag to θ7tag. When the operator performs an advance operation, the robot control unit 81 moves the ultrasonic probe 101 to the next point. On the other hand, when the operator performs a return operation, the robot control unit 81 moves the ultrasonic probe 101 to the previous point. Forward and backward movements can be performed, for example, by pressing the foot pedal 96, operating the control panel 92, or by voice recognition.

[0035] In automatic operation mode, the control panel 92 of the console device 90 displays the points (movement trajectories) registered in direct teaching mode in three dimensions, as shown in Figure 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 control panel 92.

[0036] When applying ultrasound diagnosis to catheter treatment, if the operator pre-teaches the ultrasound probe 101 to align with the central axis (length direction) of the patient's blood vessel, they can automatically move the ultrasound probe 101 along the central axis of the blood vessel simply by operating the foot pedal 96 in automatic operation mode. This allows a single operator to advance the guidewire while confirming the position of the patient's blood vessel from the ultrasound echo image by operating the ultrasound probe 101.

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

[0038] Figure 5 is a flowchart showing an example of collision detection processing performed by the robot control unit 81 of the robot control device 80. This processing is repeatedly performed at predetermined time intervals (for example, every few milliseconds or every tens of milliseconds).

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

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

[0041] The restricted area is the area within the movable area where the movement of the robot arm 21 is restricted. When performing an ultrasound diagnosis by pressing the ultrasound probe 101 against the surface of the patient's thigh, a certain part of the thigh is the restricted area. In this embodiment, the restricted area is initially set as a circular (sector-shaped) region enclosed by the assumed maximum radius of the thigh (assumed maximum thigh radius) with a predetermined position O as the center of the thigh in a cross-sectional view of the thigh, as shown in Figure 6. 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) region with a radius (collision position radius) equal to the distance between the end-effector position P (position of the ultrasound probe 101) and the predetermined position O at the time of collision. 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, but may also be elliptical or egg-shaped. Furthermore, the restricted area may be set to a cylindrical or tapered shape in the depth direction of Figure 6. The operation of the robot device 20 when the end-effector (ultrasonic probe 101) of the robot arm 21 enters the restricted area under safe conditions will be described later.

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

[0043] When safety processing is performed, the robot control unit 81 first receives the lifting position Z1 of the lifting axis J1 and the rotation angles θ2 to θ7 of the joint axes J2 to J7 from encoders 35b to 37b, 44b, and 55b to 57b (S200), and calculates the end-effector position P, the evacuation distance L, and the evacuation speed V, respectively (S210). The calculation of the end-effector position P is described above. The evacuation distance L is the cumulative amount of movement of the end-effector position P since transitioning to the safe state, and can be calculated by multiplying the distance between the end-effector position P calculated this time and the end-effector position calculated last time. The evacuation speed V can be calculated by dividing the distance between the end-effector position P calculated this time and the end-effector position calculated last time by the execution time interval of the safety processing.

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

[0045] In the safe state, if the robot arm 21 moves along the lifting axis Z1 due to a reaction force from a collision with another object, a torque proportional to the lifting speed V1 is output in the direction of that movement. Also, if the robot arm 21 rotates around the joint axes J2~J7 due to a reaction force from a collision with another object, a torque proportional to the angular velocity ω2~ω7 is output in the direction of that rotation. Figure 8 is an explanatory diagram showing the compensation torques for the lifting axis J1 and each joint axis J2~J7 set in the normal state and the safe state, respectively. In the safe state, the compensation torques Tc1~Tc7 include compensation torque for static friction (static friction compensation) and compensation torque for viscous friction (viscous friction compensation). The torques corresponding to the lifting speed V1 and angular velocity ω2~ω7 mentioned above are added to the viscous friction compensation term. Note that the compensation torques for the lifting axis J1 and joint axes J5~J7 include compensation torque in the direction that cancels out the load torque due to its own weight (gravity compensation) in both the normal state and the safe state. Since the joint axes J2 to J4 extend vertically in their axial direction, gravity compensation is not required.

[0046] These safety measures allow the robot device 20 to retract the robot arm 21 that has collided with an object (worker) in a direction that moves it away from the object. As a result, the pressing force of the robot arm 21 can be quickly reduced, and the safety of the worker can be sufficiently ensured. Furthermore, the retraction movement of the robot arm 21 is performed by torque corresponding to the external force acting on the robot arm 21. Therefore, when no external force is applied to the robot arm 21, no torque corresponding to the external force is output. This allows the robot device 20 to retract the robot arm 21 only by the amount necessary to reduce the pressing force, thereby suppressing the occurrence of secondary damage, such as collision with other objects during the retraction movement.

[0047] The robot control unit 81 terminates the safety state (S300) and ends the safety process if it determines in S220 that the end-effector position P is within the restricted area, in S230 that the retraction distance L exceeds the threshold Lref, in S240 that the retraction speed V exceeds the threshold Vref, or in S250 that a predetermined time has elapsed since transitioning to the safety state. Specifically, the robot control unit 81 controls each motor 35a~37a, 44a, 55a~57a so that the retraction movement of the robot arm 21 is stopped. This prevents unexpected movements from occurring during the retraction movement of the robot arm 21 and suppresses the occurrence of secondary damage.

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

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

[0050] For example, in the embodiment described above, the robot device 20 detects external forces acting on the robot arm 21 due to collisions with other objects by determining whether the lifting speed V1 of the lifting axis J1 and the angular velocities ω2 to ω7 of the joint axes J2 to J7 are greater than the corresponding thresholds Z1ref, ω2ref to ω7ref. However, the robot device 20 may also detect external forces acting on the robot arm 21 due to collisions with other objects by detecting the torque acting on the lifting axis J1 and the joint axes J2 to J7 using a torque sensor. In this case, the robot control unit 81 only needs to set a compensation torque that is proportional to the detected torque in the direction of the detected torque. Alternatively, the robot device 20 may directly detect external forces acting on the robot arm 21 using a 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 external forces acting on the robot arm 21. Therefore, the robot control unit 81 can use a transformation matrix to convert the force component and torque component detected by the force sensor 61 into torques for the lifting axis J1 and each joint axis J2 to J7, and then set the compensation torque.

[0051] Furthermore, in the embodiment described above, the robot control unit 81 controls each motor 35a~37a, 44a, 55a~57a so that the robot arm 21 retracts in the direction of the retraction direction, with the direction of the external force acting on the robot arm 21 due to a collision with another object (the direction of the lifting speed V1 and angular velocity ω2~ω7). However, the robot control unit 81 may also set the direction of the robot arm 21's retraction movement in the opposite direction to the direction of the robot arm 21's movement during a collision (the lifting direction of the lifting axis J1 and the rotation direction of the joint axes J2~J7).

[0052] Furthermore, in the embodiment described above, the robot device 20 is configured as a 7-axis articulated robot capable of translational motion in three directions and rotational motion in three directions. However, the number of axes can be any number. Also, the robot device 20 may be configured as a so-called vertical articulated robot or a horizontal articulated robot.

[0053] As described above, the robot device of this disclosure controls the drive unit so that the robot body moves in a predetermined direction when an external force acting on the robot body due to contact with an object is detected. This makes it possible to mitigate the pushing force of the robot body when it collides with an object, thereby further enhancing the safety of workers and others.

[0054] In the robot device of this disclosure, the control unit may control the drive unit such that, as the safety state, the robot body moves back with a larger driving force the greater the detected external force. In this way, when the robot body collides with another object (worker), the pushing force of the robot body can be mitigated by the necessary amount, thereby further enhancing the safety of workers and others.

[0055] Furthermore, in the robot apparatus of this disclosure, the control unit may control the drive unit so that the robot body moves to a retraction position in the direction of the detected external force as the safety state. In this way, the retraction direction of the robot body can be appropriately determined by a simple process.

[0056] Furthermore, the robotic device of this disclosure includes a position detection unit for detecting the position of the robot body, wherein the robot body is the robot body of a medical robot used for diagnosing and treating patients, and the control unit controls the drive unit so that the robot body operates based on the assumed thigh position of the patient, and the thigh position may be changed 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 the thigh of a patient, the position of the thigh, which varies from person to person, can be appropriately grasped.

[0057] Furthermore, in the robot device of this disclosure, the control unit may terminate the retraction operation when the robot body enters a restricted area set within the movable area due to the retraction operation while in the safe state. This prevents unexpected movements from occurring during the retraction operation and suppresses the occurrence of secondary damage. In this case, the control unit may include a position detection unit for detecting the position of the robot body, and when an external force acting on the robot body is detected by the external force detection unit, the control unit may set a predetermined range with the position of the robot body detected by the position detection unit as the boundary for the restricted area. This allows the restricted area to be set appropriately.

[0058] Furthermore, in the robot device of this disclosure, the control unit may terminate the retraction operation when a predetermined time has elapsed since transitioning to the safe state, when the amount of movement 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. This makes it possible to avoid unexpected movements during the retraction operation and suppress the occurrence of secondary damage.

[0059] Furthermore, in the robot device of this disclosure, the robot body has an arm, the drive unit has a motor that drives the joint axis of the arm, the external force detection unit detects the angular velocity of the joint axis or the torque acting on the joint axis 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 proper retraction.

[0060] Alternatively, in the robot device of the present disclosure, the robot body may have an arm, the drive unit may have a motor that drives the 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 the value detected by 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] Furthermore, this disclosure is not limited to the form of a robotic device, but can also be in the form of an ultrasound diagnostic system. [Industrial applicability]

[0062] This disclosure can be used in industries such as the manufacturing of robotic devices and ultrasound diagnostic systems. [Explanation of Symbols]

[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 Posture holding axis, 35 First arm drive device, 35a Motor, 35b Encoder, 35c Amplifier, 36 Second arm drive device, 36a Motor, 36b Encoder, 36c Amplifier, 37 Posture holding device, 37a Motor, 37b Encoder, 37c Amplifier, 40 Lifting device, 41 First slider, 42 First guide member, 43 First ball screw axis, 44a Motor, 44b Encoder, 44c Amplifier, 45 Height adjustment mechanism, 46 Second slider, 47 Second guide member, 48 Second ball screw axis, 49 Operating handle, 50 Rotating 3-axis mechanism, 51 First rotation axis, 52 Second rotation axis, 53 Third rotation axis, 55 First rotation device, 55a Motor, 55b Encoder, 55c Amplifier, 56 Second rotation device, 56a Motor, 56b Encoder, 56c Amplifier, 57 Third rotation 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 I / O unit, 80 Robot control device, 81 Robot control unit, 82 Monitoring unit, 83 I / O 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 unit, 111 Ultrasound diagnostic control unit, 112 Image processing unit, 113 Image display unit, J1 Lifting axis, J2, J3, J4, J5, J6, J7 Joint axes.

Claims

1. The robot body and The drive unit that drives the robot body, An external force detection unit for detecting external forces acting on the robot body, A position detection unit for detecting the position of the robot body, When the external force detection unit detects an external force acting on the robot body, the control unit transitions to a safety state in which it controls the drive unit so that the robot body moves to a retraction position in a predetermined direction. A robotic device equipped with, The control unit monitors the position of the robot body detected by the position detection unit, the amount of movement of the robot body during the retraction operation after transitioning to the safe state, the movement speed during the retraction operation, and the elapsed time since transitioning to the safe state, and determines whether any of these satisfy a corresponding predetermined condition. The control unit continues the safe state as long as none of the predetermined conditions are satisfied, and terminates the safe state when any of the predetermined conditions are satisfied, and terminates the retraction operation upon termination of the safe state.

2. A robotic device according to claim 1, The control unit controls the drive unit such that, as the safety state, the robot body moves to a retraction position with a larger driving force the greater the detected external force. Robotic device.

3. A robotic device according to claim 1, The control unit controls the drive unit so that the robot body moves to a retraction position in the direction of the detected external force, as the safety state. Robotic device.

4. A robotic device according to any one of claims 1 to 3, The predetermined conditions include, in the safe state, the robot body entering a restricted area set within the movable area by the retraction operation. Robotic device.

5. A robotic device according to claim 4, When the external force acting on the robot body is detected by the external force detection unit, the control unit sets a predetermined range bounded by the position of the robot body detected by the position detection unit as the limiting area. Robotic device.

6. A robotic device according to any one of claims 1 to 3, The predetermined conditions include any of the following: a predetermined time has elapsed since transitioning to the safe state; the amount of movement of the robot body during its retraction operation in the safe state exceeds a predetermined amount; and the movement speed of the robot body during its retraction operation in the safe state exceeds a predetermined speed. Robotic device.

7. A robotic device according to any one of claims 1 to 3, The robot body has an arm, The drive unit has a motor that drives the joint axis of the arm, The external force detection unit detects the angular velocity of the joint axis or the torque acting on the joint axis as an external force acting on the robot 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 the corresponding motor in the direction of the detected angular velocity or torque. Robotic device.

8. A robotic device according to any one of claims 1 to 3, The robot body has an arm, The drive unit has a motor that drives the joint axis 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 value detected by the force sensor is output from the corresponding motor in the direction of the detected external force. Robotic device.

9. Ultrasound probe and A robot body that holds the aforementioned ultrasonic probe at its end, The drive unit that drives the robot body, An external force detection unit for detecting external forces acting on the robot body, A position detection unit for detecting the position of the robot body, When the external force detection unit detects an external force acting on the robot body, the control unit transitions to a safety state in which it controls the drive unit so that the robot body moves to a retraction position in a predetermined direction. An ultrasound diagnostic system comprising, An ultrasonic diagnostic system wherein the control unit monitors, in the safe state, the position of the robot body detected by the position detection unit, the amount of movement of the robot body during the retraction operation after transitioning to the safe state, the speed of movement during the retraction operation, and the elapsed time since transitioning to the safe state, and determines whether any of these satisfy a corresponding predetermined condition, continues the safe state as long as none of the predetermined conditions are satisfied, and terminates the safe state when any of the predetermined conditions are satisfied, and terminates the retraction operation upon termination of the safe state.

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