Robot device and direct teaching assistance method

Abstract

This robot device comprises: a driving unit that drives a multi-joint arm unit; a detection unit that detects a position or a velocity of a predetermined portion of the arm unit; a control unit that executes assisting control of controlling the driving unit so as to assist a manual operation of the arm unit during direct teaching in which an operator manually operates the arm unit and a pose of the arm unit is recorded; a limiting unit; and a changing unit. The limiting unit executes limiting control of limiting execution of the assisting control when the position or the velocity of the predetermined portion of the arm unit detected by the detection unit exceeds a threshold value. Then the control unit changes the threshold value on the basis of the pose of the arm unit.

Description

Technical Field

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[0001] This specification discloses a robot device and an assist method for direct teaching.

Background Art

[0002] Conventionally, in a robot device that performs assist control to assist a worker's manual operation of an arm during direct teaching, it has been proposed to control such that the assist force is restricted as the hand of the arm approaches a stop area (see, for example, Patent Document 1). <​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​A drive unit that drives the aforementioned arm portion, A detection unit for detecting the position or speed of a predetermined portion of the arm portion, In direct teaching, in which an operator manually operates the arm and records the posture of the arm, a control unit performs assist control to control the drive unit to assist the manual operation of the arm, When the position or speed of a predetermined part of the arm detected by the detection unit exceeds a threshold, a limiting unit executes limiting control to restrict the execution of the assist control. A modification unit that changes the threshold based on the posture of the arm portion, The gist of it is that it is equipped with the following features.

[0008] According to the robotic device of this disclosure, the limitations of the assist control can be optimized according to the posture of the arm, thereby ensuring safety while improving operability during direct teaching.

[0009] Alternatively, a direct teaching assistance method may be used instead of the robotic apparatus described herein. This method can achieve the same effects as the robotic apparatus described herein. [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 relationships between the robotic device, the console device, and the ultrasound diagnostic device. [Figure 4] This is an explanatory diagram showing an example of an area that can be accessed and an area that cannot be accessed. [Figure 5] This flowchart shows an example of assist control processing. [Figure 6] A flowchart illustrating an example of a state transition process. [Figure 7] A flowchart illustrating an example of a warning process. [Figure 8] It is an explanatory diagram showing an example of the relationship between an area, a risk level, an output torque, a generated sound, and a state transition. [Figure 9] It is a flowchart showing an example of threshold setting processing. [Figure 10A] It is an explanatory diagram showing an accessible area of the right hand posture. [Figure 10B] It is an explanatory diagram showing an accessible area of the left hand posture. [Figure 11] It is a flowchart showing assist control processing of a modified example. [Figure 12] It is a flowchart showing state transition processing of a modified example. [Figure 13] It is an explanatory diagram showing an example of the relationship between an area, a risk level, an output torque, a generated sound, a speed threshold, and a state transition. [Figure 14] It is a flowchart showing threshold setting processing of a modified example.

Mode for Carrying Out the Invention

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

[0012] FIG. 1 is an external perspective view of an ultrasonic diagnostic system 10 including a robot device 20 according to the present embodiment. FIG. 2 is a side view of the robot device 20. FIG. 3 is a block diagram showing an electrical connection relationship between the robot device 20, a console device 90, and an ultrasonic diagnostic device 100. In FIG. 1, the left - right direction is the X - axis, the front - rear direction is the Y - axis direction, and the up - down direction is the Z - axis direction.

[0013] The ultrasonic diagnostic system 10 of this embodiment holds the ultrasonic probe 101 at the end of the robotic arm 21, and acquires ultrasonic echo images by operating the robotic device 20 so that the ultrasonic probe 101 is pressed against the body surface of the patient. This ultrasonic diagnostic system 10 is used, for example, in catheter treatment. An operator (surgeon) who operates the guide wire of the catheter presses the ultrasonic probe 101 against the surface of the patient's thigh, and while recognizing the positional relationship between the tip of the guide wire and the blood vessel from the obtained ultrasonic echo image, advances the guide wire, so that the guide wire can accurately pass through the center of the occluded or stenotic part of the blood vessel.

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

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

[0016] The console device 90 is installed separately from the robot device 20 and instructs various operations of the robot device 20 and displays various information, including the status of the robot device 20. The console device 90 comprises a console control unit 91 that controls the entire device, an operation panel 92 that displays various information and can be operated by the operator via touch, 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 that stops the operation of the robot device 20 in an emergency. Furthermore, the console device 90 is connected to a foot pedal 96 and a joint controller 97 via cables. The foot pedal 96 and the joint controller 97 are operating members that can issue various instructions.

[0017] As shown in Figures 1 to 3, the robot device 20 comprises a base 25, a robot arm 21 mounted 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 Figure 3) for controlling the robot arm 21.

[0018] As shown in Figures 1 and 2, casters 26 with stoppers are attached to the four corners of the underside of the base 25. The robot device 20 can be moved freely using the casters 26. In addition, locking parts 28 are provided at multiple locations (for example, three locations) on the underside of the base 25, which protrude vertically downward when a lever 27 is pressed down, locking (fixing) the robot device 20 so that it cannot be moved.

[0019] As shown in Figure 1, the robot arm 21 includes a first arm 22, a second arm 23, a base 24, a first arm drive unit 35, a second arm drive unit 36, a posture 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 "joint shaft J2") that extends in the vertical direction (Z-axis direction). The first arm drive unit 35 comprises a motor 35a (servo motor), an encoder 35b, and an amplifier 35c. The rotation axis of the motor 35a is connected to the first joint shaft 31 via a reduction gear (not shown). The first arm drive unit 35 rotates (swivels) the first arm 22 along the horizontal plane (XY plane) with the first joint shaft 31 as a pivot point by rotationally driving the first joint shaft 31 with the motor 35a. The encoder 35b is attached to the rotation axis of the motor 35a and is configured as a rotary encoder that detects the rotational displacement of the motor 35a. The amplifier 35c is a drive unit for driving the motor 35a by switching a switching element.

[0021] The base end of the second arm 23 is connected to the tip of the first arm 22 via a second joint shaft 32 (hereinafter sometimes referred to as "joint shaft J3") that extends in the vertical direction. The second arm drive unit 36 ​​comprises a motor 36a (servo motor), an encoder 36b, and an amplifier 36c. The rotation axis of the motor 36a is connected to the second joint shaft 32 via a reduction gear (not shown). The second arm drive unit 36 ​​rotates (swivels) the second arm 23 along the horizontal plane with the second joint shaft 32 as a pivot point by rotationally driving the second joint shaft 32 with the motor 36a. The encoder 36b is attached to the rotation axis of the motor 36a and is configured as a rotary encoder that detects the rotational displacement of the motor 36a. The amplifier 36c is a drive unit for driving the motor 35a by switching a switching element.

[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 (servo motor) 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. Therefore, the robot arm 21 moves up and down along the lifting axis J1. The encoder 44b is configured as a linear encoder that detects the vertical position (lifting 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 (servo motor) 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 (servo motor) 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 (servo motor) 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] 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 Z1 of the lifting axis J1 and the rotation angles θ2 to θ7 of the joint axes J2 to J7 of the robot arm 21, which correspond 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. Then, the motors 35a to 37a, 44a, 55a to 57a are controlled 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. Conversely, 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. In this embodiment, the distance between two adjacent points of the registered points is interpolated using an interpolation method such as linear interpolation. As a result, the end effector (ultrasonic probe 101) of the robot arm 21 moves along a movement trajectory that has been interpolated to pass through the registered points.

[0034] Here, the robot device 20 has defined accessible areas where certain parts of the robot arm 21 (for example, end-effector, joint, or link parts of the robot arm 21) can enter, and inaccessible areas where certain parts of the robot arm 21 cannot enter. The accessible areas are areas where the robot arm 21 can be safely operated. The inaccessible areas are defined outside the accessible areas. In this embodiment, as shown in Figure 4, the accessible areas are set as a rectangular area centered on a position O offset in the X direction in an XY coordinate system based on the base 25. However, the accessible areas are not limited to rectangular shapes and may be set as elliptical or circular shapes, etc.

[0035] In direct teaching mode, the robot control unit 81 basically performs assist control by controlling each motor 35a~37a, 44a, 55a~57a so that an assist force acts in the direction of the operator's operation of the robot arm 21 when a predetermined part of the robot arm 21 is within the accessible area. The direction of operation of the robot arm 21 can be obtained based on detection signals from the force sensor 61 and from the encoders 35b~37b, 44b, 55b~57b. On the other hand, the robot control unit 81 restricts assist control when a predetermined part of the robot arm 21 approaches the boundary between the accessible and inaccessible areas. This prevents the predetermined part of the robot arm 21 from being operated beyond the accessible area.

[0036] Next, we will describe in detail the operation that limits the assist control. Figure 5 is a flowchart showing an example of the assist control process performed by the robot control unit 81.

[0037] In the assist control process, the robot control unit 81 (CPU) first inputs position signals from each encoder 35b~37b, 44b, 55b~57b and the magnitude and direction of external forces from the force sensor 61 (step S100). Next, the robot control unit 81 calculates the position P (coordinate value in the XY coordinate system with respect to the base 25) of a predetermined part of the robot arm 21 (for example, the end effector, joint, or link part of the robot arm 21) using forward kinematics based on the input position signals (step S110). Then, the robot control unit 81 determines the degree of safety risk based on the calculated position P (step S120). The degree of risk includes, for example, minimum, small, medium, large, and maximum, in descending order from lowest to highest. Each degree of risk has corresponding area thresholds A1, A2, A3, and A4 (coordinate values ​​in the XY coordinate system with respect to the base 25 at each area boundary) (see Figure 4). If position P is inside area threshold A1, the risk level is determined to be minimal. If position P is outside area threshold A1 but inside area threshold A2, the risk level is determined to be low. If position P is outside area threshold A2 but inside area threshold A3, the risk level is determined to be medium. If position P is outside area threshold A3 but inside area threshold A4, the risk level is determined to be high. Furthermore, if position P is outside area threshold A4, the risk level is determined to be maximum. In this embodiment, area threshold A4 is set as the boundary between the inaccessible area and the inaccessible area. Thus, the risk level is determined to increase as position P approaches the inaccessible area. The risk level determination may also take into account the operating direction of the robot arm 21 obtained in step S100 (e.g., whether the operating direction is toward the inaccessible area or toward the inaccessible area).

[0038] If the robot control unit 81 determines that the risk level is minimal (YES in step S130), it determines whether the pause execution flag F, described later, is valued at 1 (step S140). If the robot control unit 81 determines that the pause execution flag F is valued at 1, it sets the pause execution flag F to value 0 (step S150) and proceeds to step S160. If the pause execution flag F is not valued at 1 but is valued at 0, it skips step S150 and proceeds to step S160. Next, the robot control unit 81 executes the assist control described above (step S160). Then, the robot control unit 81 determines whether the termination of direct teaching has been requested (step S190). If the robot control unit 81 determines that the termination of direct teaching has not been requested, it returns to step S100 and repeats the processing in steps S100 to S180. On the other hand, if the robot control unit 81 determines that the termination of direct teaching has been requested, it terminates the assist control process.

[0039] In step S130, if the robot control unit 81 determines that the risk level determination result is not minimal, that is, small, medium, large, or extremely large (NO in step S130), it performs a state transition process to restrict assist control (step S170) and a warning process to inform the user that the risk level is increasing (step S180), and then proceeds to step S190.

[0040] The state transition process is performed by executing the state transition process shown in Figure 5. In the state transition process, the robot control unit 81 determines whether the risk level is small (step S200), medium (step S210), or large (step S220). If the robot control unit 81 determines that the risk level is small, it performs assist force attenuation control to reduce the assist force (step S230) and terminates the state transition process. Assist force attenuation control is performed by controlling each motor 35a~37a, 44a, 55a~57a to assist the manual operation of the robot arm 21 with less assist force than normal assist control. The robot control unit 81 may also control the system so that a force (repulsive force) acts in the opposite direction to the operating direction of the robot arm 21 (repulsive control).

[0041] If the robot control unit 81 determines in step S210 that the risk level is medium, it determines whether the pause execution flag F is valued at 0 (step S240). If the robot control unit 81 determines that the pause execution flag F is valued at 0, it performs a pause by controlling each motor 35a~37a, 44a, 55a~57a to maintain the robot arm 21 in its current position (step S250). The pause can be performed, for example, by position feedback based on detection signals from encoders 35b~37b, 44b, 55b~57b so that the lifting axis J1 and joint axes J2~J7 of the robot arm 21 are maintained in their current positions. As a result, a holding force is generated in the robot arm 21, making it difficult or impossible for the operator to manually operate the robot arm 21. Once the robot control unit 81 performs a pause, it waits for a predetermined release operation to be performed to cancel the pause (step S260). The release operation can be performed, for example, by an operator operating the operation panel 92 of the console device 90, or by providing a release switch on the robot device 20 or the console device 90 and having the operator operate the release switch. When the robot control unit 81 determines that the release operation has been performed, it releases the pause (step S270), sets the pause execution flag to a value of 1 (step S280), and terminates the state transition process. This allows the operator to resume manual operation of the robot arm 21.

[0042] Even if the robot control unit 81 determines in step S210 that the risk level is medium, if it determines in step S240 that the pause execution flag F is value 1 and not value 0, it will execute assist force damping control and rebound control (step S230) without performing a pause and terminate the state transition process. As a result, once the pause is released and the pause execution flag F is set to value 1, the pause will not be re-executed until the pause execution flag F is set to value 0. As described above, the pause execution flag F is set to value 0 in steps S130 to S150 of the assist control process when the risk level is minimal (the position P of a predetermined part of the robot arm 21 is inside the area threshold A1) and the pause execution flag F is value 1. Therefore, if a pause is performed when the position P of a predetermined part of the robot arm 21 exceeds the area threshold A2, the pause will not be re-executed until it falls below the area threshold A1, which is inside the area threshold A2. This is to avoid repeated execution and release of pauses when the position of a predetermined part of the robot arm 21 is near the area threshold L2.

[0043] If the robot control unit 81 determines in step S220 that the risk level is high, it stops the control of each motor 35a~37a, 44a, 55a~57a (servo off) (step S290). Unlike a temporary pause, servo off does not apply an active holding force to the robot arm 21. Therefore, in the servo off state, the operator can manually operate the robot arm 21 to return it to a safer area. The robot control unit 81 then waits for a predetermined return operation to be performed (step S300). The return operation can be performed, for example, by the operator operating the operation panel 92 of the console device 90, or by providing a return switch on the robot device 20 or the console device 90 and operating the return switch. If the robot control unit 81 determines that a return operation has been performed, it releases the servo off and performs a predetermined return operation (step S310), and terminates the state transition process. The return operation includes returning the encoder to its home position. In this embodiment, the attitude holding device 37 is controlled so that the first rotation axis 51 of the three-axis rotation mechanism 50 is always facing a certain direction (X-axis direction). Therefore, if the robot arm 21 is manually operated by the operator after the servo off operation is performed, the orientation of the first rotation axis 51 of the three-axis rotation mechanism 50 will deviate from the above-mentioned certain direction, making it uncontrollable. To address this, the robot control unit 81 controls the motors 35a~37a, 44a, 55a~57a to drive so that the encoders 35b~37b, 44b, 55b~57b return to their home positions as a recovery operation after the servo off operation is performed. After this recovery operation is performed, the operator can manually operate the robot arm 21 to resume direct teaching.

[0044] If the robot control unit 81 determines in steps S200 to S220 that the risk level is neither low, medium, nor high, it determines that it is extremely high and performs a power cutoff by controlling the drive power supply unit 72 to stop supplying power to each amplifier 35c to 37c, 44c, and 55c to 57c (step S320), terminates direct teaching (step S330), and ends the state transition process. By performing a power cutoff when a predetermined part of the robot arm 21 reaches an area that cannot be entered, the occurrence of danger can be avoided.

[0045] Next, the details of the warning process will be explained. Figure 7 is a flowchart showing an example of the warning process performed by the robot control unit 81. In the warning process, the robot control unit 81 determines whether the risk level is low or medium (step S400). If the robot control unit 81 determines that the risk level is low or medium, it outputs a first warning sound from the speaker 93 (step S410) and outputs a control signal to the console control unit 91 of the console device 90 so that a first warning display is shown on the operation panel 92 (step S420), and then terminates the warning process. The first warning sound and the first warning display are intended to warn the operator that a predetermined part of the robot arm 21 is approaching a restricted area. On the other hand, if the robot control unit 81 determines that the risk level is neither low nor medium, that is, that the risk level is high or extremely high, it outputs a second warning sound from the speaker 93 that is different from the first warning sound (step S430), and outputs a control signal to the console control unit 91 of the console device 90 so that a second warning display different from the first warning display is displayed on the operation panel 92 (step S440), and terminates the warning process. The second warning sound and second warning display are intended to warn the worker at a higher warning level than the first warning sound and second warning display. Note that if the risk level is extremely low, the warning process is not executed, so no warning sound or warning display is output, and there is no sound or display.

[0046] Figure 8 is an explanatory diagram illustrating an example of the relationship between area, risk level, output torque, warning sound, area threshold, and state transitions. As shown in the figure, the risk level increases from minimal to maximum as a predetermined part of the robot arm 21 approaches the boundary between the accessible and inaccessible areas. The state of the robot device 20 transitions in the following order as the risk level increases: pause, servo off, and power supply cut off. In addition, there is no sound when the risk level is minimal, a first warning sound is emitted when the risk level changes from minimal to small, and a second warning sound is emitted when the risk level changes from medium to large. Furthermore, a first warning display is shown along with the first warning sound, and a second warning display is also shown along with the second warning sound. Through these, the operator can easily recognize when a predetermined part of the robot arm 21 is approaching or has entered the inaccessible area.

[0047] Next, the operation of changing the area threshold used for risk assessment will be described. Figure 9 is a flowchart of an example of the threshold setting process performed by the robot control unit 81. When the threshold setting process is performed, the robot control unit 81 acquires the current posture of the robot arm 21 based on the detection signals from each encoder 35b~37b, 44b, 55b~57b (step S500). In this embodiment, the first arm 22 and the second arm 23 of the robot device 20 are configured as horizontal joint arms, and the posture of the robot arm 21 includes a right-handed posture in which the first arm 22 and the second arm 23 are operated in a right-handed system, and a left-handed posture in which the first arm 22 and the second arm 23 are operated in a left-handed system. Next, the robot control unit 81 sets area thresholds A1, A2, A3, and A4 according to the acquired posture (step S510). Then, the robot control unit 81 registers the set area thresholds A1, A2, A3, and A4 in the storage unit 85 (step S520) and ends the threshold setting process.

[0048] Figure 10A is an explanatory diagram showing the accessible area in the right-handed posture, and Figure 10B is an explanatory diagram showing the accessible area in the left-handed posture. In the XY coordinate system based on the base 25 of the robot device 20, the accessible areas are defined as being shifted in the X-axis direction for the right-handed posture and the left-handed posture, as shown in the figures. The area thresholds A1, A2, A3, and A4 are set according to the accessible areas defined for the right-handed posture and the left-handed posture, respectively. This allows for accurate determination of the risk level in direct teaching, regardless of whether the robot arm 21 is operated in the right-handed or left-handed posture, and enables appropriate responses according to the risk level.

[0049] Here, the correspondence between the main elements of the embodiment and the main elements of the present disclosure as described in the claims will be explained. Specifically, the robot device 20 of this embodiment corresponds to the robot device of the present disclosure, the robot arm 21 corresponds to the arm part, the motors 35a~37a, 44a, 55a~57a and amplifiers 35c~37c, 44c, 55c~57c correspond to the drive part, the robot control unit 81 that performs assist control processing corresponds to the control unit, the robot control unit 81 that performs state transition processing corresponds to the limiting unit, and the robot control unit 81 that performs threshold change processing corresponds to the change unit. In addition, the robot control unit 81 that performs warning processing and the operation panel 92 and speaker 93 of the console device 90 correspond to the warning unit.

[0050] 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.

[0051] For example, the robot control unit 81 determines the risk level based on the position P of a predetermined part of the robot arm 21, but it may also determine the risk level based on the movement speed of a predetermined part of the robot arm 21. In this case, the robot control unit 81 may execute the assist control process in Figure 11 instead of Figure 5, and the state transition process in Figure 12 instead of Figure 6. Note that the same step numbers are used for each process in the assist control process in Figure 11 that are the same as the assist control process in Figure 5. Similarly, the same step numbers are used for each process in the state transition process in Figure 12 that are the same as the state transition process in Figure 6.

[0052] In the assist control process of FIG. 11, the robot control unit 81 calculates the speed V of a predetermined portion of the robot arm 21 from the detection signals of the encoders 35b to 37b, 44b, 55b to 57b input in step S100 (step S110B). This process can be performed by calculating the position of a predetermined portion of the robot arm 21 from the detection signal and calculating the differential of the calculated position. Subsequently, the robot control unit 81 determines the risk level based on the calculated speed V (step S120B). For example, the risk levels include extremely low, low, medium, and high in ascending order, and speed thresholds V1, V2, V3 (V1 < V2 < V3) are defined corresponding to each risk level (see FIG. 4). When the speed V is less than or equal to the speed threshold V1, the risk level is determined to be extremely low. When the speed V is greater than the speed threshold V1 and less than or equal to the speed threshold V2, the risk level is determined to be low. When the speed V is greater than the speed threshold V2 and less than or equal to the speed threshold V3, the risk level is determined to be medium. When the speed V is greater than the speed threshold V3, the risk level is determined to be high. The speed threshold V3 is set to the allowable limit speed of the robot arm 21 or a speed slightly lower than that. Thus, the risk level is determined to increase as the speed V approaches the allowable limit speed. After determining the risk level, if the robot control unit 81 determines that the determination result is low (YES in step S130B), it executes assist control (step S160). On the other hand, if the determination result of the risk level is not extremely low, that is, if it is determined to be any of low, medium, or high (NO in step S130), it executes the state transition process of FIG. 12 (step S170B) and executes a warning process (step S180B). Although not shown, in the warning process, when the risk level is low or medium, the output of the first warning sound and the first warning display are performed. When the risk level is high, the output of the second warning sound and the second warning display are performed.

[0053] In the state transition process shown in Figure 12, if the robot control unit 81 determines that the risk level is small (YES in step S200), it executes assist force damping control and rebound control (step S230) and terminates the state transition process. On the other hand, if the robot control unit 81 determines that the risk level is not small but medium (NO in step S200, YES in step S210), it performs a pause (step S250), waits for the release operation to be performed (step S260), and then releases the pause (step S260). The pause and release operations are described above. Note that when a pause is performed, the velocity V becomes 0, so the pause execution flag F to avoid repeated pause execution and release is unnecessary. Furthermore, if the robot control unit 81 determines that the risk level is neither small nor medium (NO in step S200, NO in step S210), it determines that it is large, cuts off the power supply (step S320), terminates direct teaching (step S330), and terminates the state transition process.

[0054] Figure 13 is an explanatory diagram illustrating an example of the relationship between area, risk level, output torque, warning sound, speed threshold, and state transitions. As shown in the figure, the risk level increases sequentially from very small to very large as the speed of a predetermined part of the robot arm 21 approaches the permissible limit speed. The state of the robot device 20 transitions from temporary stop to power cut-off as the risk level increases. In addition, there is no sound when the risk level is low, a first warning sound is emitted when the risk level changes from low to medium, and a second warning sound is emitted when the risk level changes from medium to high. Furthermore, a first warning display is made along with the first warning sound, and a second warning display is made along with the second warning sound. Through these, the operator can easily recognize that the operating speed of the robot arm 21 is too high.

[0055] Furthermore, in the embodiment described above, the robot control unit 81 sets thresholds (area thresholds) based on the posture of the robot arm 21 (right hand posture, left hand posture), but the thresholds may be set based on the operation mode. In this case, the robot control unit 81 can perform the threshold setting process in Figure 14 instead of Figure 9. Note that the same step numbers are used for each process in the threshold setting process in Figure 14 that are the same as those in the threshold setting process in Figure 9. In the threshold setting process in Figure 14, the robot control unit 81 acquires the current operation mode (step S500B). Here, the operation mode includes, in addition to the direct teaching mode described above, a linear interpolation mode in which, when an operating member (e.g., joint controller 90) is operated by an operator during teaching, the end-effector of the robot arm 21 is moved by an amount corresponding to the amount of operation in the direction corresponding to the operation, and an individual axis operation mode in which the lifting axis J1 and each joint axis J2 to J7 are individually specified and operated. The linear interpolation mode is performed by detecting the direction and amount of operation of the operating member by the operator to set the target position of the end effector of the robot arm 21, and then controlling each motor 35a~37a, 44a, 55a~57a by setting the target lifting position Z1tag of the lifting axis J1 and the target rotation angles θ2tag~θ7tag of the joint axes J2~J7 using inverse kinematics based on the set target position of the end effector. In addition, each axis operation mode is performed by setting a target value (target lifting position Z1tag or target rotation angle θ2tag~θ7tag) of the axis specified by the operator from the lifting axis J1 or joint axes J2~J7 and controlling the corresponding motor. This makes it possible to fine-tune the posture of the robot arm 21 registered in direct teaching mode, for example. The robot control unit 81 then sets a threshold (area threshold) according to the operation mode (step S510B), registers the set threshold in the storage unit 83 (step S520), and ends the threshold setting process. The threshold can be set such that, for example, when linear interpolation mode or individual axis driving mode is selected, the threshold is made larger compared to direct teaching mode so that assist control is less restricted.

[0056] Furthermore, in the above-described embodiment, the robot control unit 81 outputs a warning sound and displays a warning according to the risk level during the warning process, but it is also possible to output only one of the warning sound or display a warning.

[0057] 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.

[0058] As explained above, the robot device of this disclosure allows for the optimization of the assist control limits according to the posture of the arm, thereby ensuring safety while improving operability during direct teaching.

[0059] In the robotic apparatus of this disclosure, the arm portion has a horizontal articulated arm, and the posture of the arm portion has a right-handed posture in which the arm portion operates in a right-handed system and a left-handed posture in which the arm portion operates in a left-handed system, and the modification portion may set different thresholds for the right-handed posture and the left-handed posture. In this way, regardless of whether direct teaching is performed in the right-handed posture or the left-handed posture, the assist control can be appropriately limited.

[0060] Furthermore, in the robot device of this disclosure, the modification unit may change the threshold value based on the operating mode of the arm. This allows for proper limitation of assist control regardless of the operating mode.

[0061] Furthermore, in the robotic apparatus of this disclosure, the arm portion may move along a movement trajectory interpolated to pass through a plurality of recorded postures after the direct teaching has been performed. This allows the arm portion to move smoothly.

[0062] Furthermore, in the robot device of this disclosure, the limiting unit may, when the position of a predetermined part of the arm exceeds a first threshold, execute a first limiting control as the limiting control; when the position of the arm exceeds a second threshold that poses a higher risk to safety than the first threshold, execute a second limiting control that requires a predetermined return operation to release the limiting control as the limiting control; and once the first limiting control is executed, the limiting unit may not re-execute the first limiting control even if the position of the arm exceeds the first threshold until the position of the predetermined part of the arm falls below a third threshold that poses a lower risk to safety than the first threshold. This allows the operator to appropriately recognize the state of the arm during direct teaching. In addition, it is possible to avoid repeated execution and release of the first limiting control when the position of the predetermined part of the arm is near the first threshold.

[0063] Furthermore, the robot device of this disclosure may include a warning unit that outputs a first warning sound or a first warning display when the position or speed of a predetermined part of the arm exceeds a first threshold, and outputs a second warning sound different from the first warning sound or a second warning display different from the first warning display when the position or speed of the predetermined part of the arm exceeds a second threshold that poses a higher risk to safety than the first threshold. This allows the operator to appropriately recognize the state of the arm during direct teaching.

[0064] Furthermore, this disclosure is not limited to the form of a robotic device, but can also be in the form of an assist method for assisting the manual operation of the robot arm 21 in direct teaching of a robotic device.

[0065] This specification also discloses technical concepts in which "the robot device described in claim 1" is changed to "the robot device described in claim 1 or 2" in claim 3 of the original application, technical concepts in which "the robot device described in claim 1" is changed to "the robot device described in any one of claims 1 to 3" in claim 4 of the original application, and technical concepts in which "the robot device described in any one of claims 1 to 4" is changed to "the robot device described in any one of claims 1 to 5" in claim 6 of the original application. [Industrial applicability]

[0066] This disclosure can be used in industries such as the manufacturing of robotic devices. [Explanation of Symbols]

[0067] 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 Direct teaching enable 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.

Claims

1. A robotic device having a multi-jointed arm, A drive unit that drives the aforementioned arm portion, A detection unit for detecting the position or speed of a predetermined portion of the arm portion, In direct teaching, in which an operator manually operates the arm and records the posture of the arm, a control unit performs assist control to control the drive unit to assist the manual operation of the arm, When the position or speed of a predetermined part of the arm detected by the detection unit exceeds a threshold, a limiting unit executes limiting control to restrict the execution of the assist control. A modification unit that changes the threshold based on the posture of the arm portion, A robotic device equipped with the following features.

2. A robotic device according to claim 1, The aforementioned arm section has a horizontal multi-joint arm, The arm portion has two postures: a right-handed posture in which the arm portion operates in a right-handed system, and a left-handed posture in which the arm portion operates in a left-handed system. The modification unit sets different thresholds for the right-hand posture and the left-hand posture. Robotic device.

3. A robotic device according to claim 1, The modification unit modifies the threshold based on the operating mode of the arm unit. Robotic device.

4. A robotic device according to claim 1, The arm portion moves along a movement trajectory interpolated to pass through a plurality of recorded postures after the direct teaching is performed. Robotic device.

5. A robotic device according to any one of claims 1 to 4, The limiting unit executes a first limiting control as the limiting control when the position of a predetermined part of the arm exceeds a first threshold, and executes a second limiting control as the limiting control when the position of the arm exceeds a second threshold which poses a higher risk to safety than the first threshold, and once the first limiting control is executed, the limiting unit does not re-execute the first limiting control even if the position of the arm exceeds the first threshold until the position of the predetermined part of the arm falls below a third threshold which poses a lower risk to safety than the first threshold. Robotic device.

6. A robotic device according to any one of claims 1 to 4, The system includes a warning unit that outputs a first warning sound or a first warning display when the position or speed of a predetermined part of the arm exceeds a first threshold, and outputs a second warning sound different from the first warning sound or a second warning display different from the first warning display when the position or speed of the predetermined part of the arm exceeds a second threshold that poses a higher risk to safety than the first threshold. Robotic device.

7. In direct teaching of a robotic device in which an operator manually operates a multi-jointed arm to record the posture of the arm, a direct teaching assistance method for assisting the manual operation of the arm is provided, Assist control is performed to drive the arm in order to assist the manual operation of the arm. The position or velocity of a predetermined part of the arm is detected, and if the detected position or velocity of the predetermined part of the arm exceeds a threshold, the execution of the assist control is restricted. The threshold is changed based on the posture of the arm portion. Methods for assisting with direct teaching.

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