Control apparatus and control method for robot arm, robot, control program for robot arm, and integrated electronic circuit

A control method of a robot arm, for controlling a motion of the robot arm including:

• an end effector attached to a main body of the robot arm touched and operated by a person and caused to perform a task;
• and a grip portion attached to the main body of the robot arm so as to be separated from the end effector with a gap of a predetermined size being provided therebetween, the grip portion being relatively shiftable with respect to the end effector and being gripped by the person during the operation,
• the control method comprising:
• acquiring, by a relative positional information acquisition unit, information on a relative position of the grip portion with respect to the end effector during the operation;
• obtaining, by a tracking control unit, a shift amount of the robot arm in order to perform tracking control of shifting the robot arm in accordance with an amount of variation of a size of the gap between the end effector and the grip portion so that the information on the relative position acquired by the relative positional information acquisition unit is within a range of a predetermined threshold;
• controlling, by a control unit, the robot arm so as to shift in accordance with the amount of variation of the size of the gap between the end effector and the grip portion, based on the shift amount of the robot arm obtained by the tracking control unit;
• maintaining the size of the gap between the end effector and the grip portion, by a fixing portion including a fixing member shiftable between a fixed position where the fixing member is in contact with the end effector and the grip portion to fix the end effector and the grip portion and restrict relative shift between the end effector and the grip portion, and an accommodated position where the fixed member is accommodated in the end effector or in the grip portion and allows the end effector and the grip portion to shift relatively, when the fixing member is located at the fixed position;
• switching, by a mode switch unit, between a “teaching mode” and a “playback mode” as a control mode of the robot arm;
• switching, by a fixing switch unit, between a fixing state where, when the mode switch unit switches to the “playback mode”, the fixing portion is located at the fixed position to fix the end effector and the grip portion and maintain the size of the gap between the end effector and the grip portion, and a relatively shiftable state where, when the mode switch unit switches to the “teaching mode”, the fixing portion is located at the accommodated position and allows the end effector and the grip portion to shift relatively without maintaining the size of the gap between the end effector and the grip portion;
• acquiring, by an arm tip positional information acquisition unit, positional information on the end effector of the robot arm during the “teaching mode”;
• and
• generating, by a desired trajectory generation unit, a desired trajectory of the end effector of the robot arm during the “teaching mode”, based on the arm tip positional information acquired by the arm tip positional information acquisition unit and the information on the relative position acquired by the relative positional information acquisition unit, wherein
• the control unit causes the tracking control unit to perform tracking control on the robot arm moving in accordance with a teaching operation of the person when the mode switch unit switches to the “teaching mode”, and controls the robot arm in accordance with the desired trajectory generated by the desired trajectory generation unit when the mode switch unit switches to the “playback mode”.

A non-transitory computer readable medium storing a control program of a robot arm, for controlling a motion of the robot arm including:

• an end effector attached to a main body of the robot arm touched and operated by a person and caused to perform a task;
• and a grip portion attached to the main body of the robot arm so as to be separated from the end effector with a gap of a predetermined size being provided therebetween, the grip portion being relatively shiftable with respect to the end effector and being gripped by the person during the operation,
• the control program causing a computer to execute steps of:
• acquiring, by a relative positional information acquisition unit, information on a relative position of the grip portion with respect to the end effector during the operation;
• obtaining, by a tracking control unit, a shift amount of the robot arm in order to perform tracking control of shifting the robot arm in accordance with an amount of variation of a size of the gap between the end effector and the grip portion so that the information on the relative position acquired by the relative positional information acquisition unit is within a range of a predetermined threshold;
• controlling, by a control unit, the robot arm so as to shift in accordance with the amount of variation of the size of the gap between the end effector and the grip portion, based on the shift amount of the robot arm obtained by the tracking control unit;
• maintaining the size of the gap between the end effector and the grip portion, by a fixing portion including a fixing member shiftable between a fixed position where the fixing member is in contact with the end effector and the grip portion to fix the end effector and the grip portion and restrict relative shift between the end effector and the grip portion, and an accommodated position where the fixed member is accommodated in the end effector or in the grip portion and allows the end effector and the grip portion to shift relatively, when the fixing member is located at the fixed position;
• switching, by a mode switch unit, between a “teaching mode” and a “playback mode” as a control mode of the robot arm;
• switching, by a fixing switch unit, between a fixing state where, when the mode switch unit switches to the “playback mode”, the fixing portion is located at the fixed position to fix the end effector and the grip portion and maintain the size of the gap between the end effector and the grip portion, and a relatively shiftable state where, when the mode switch unit switches to the “teaching mode”, the fixing portion is located at the accommodated position and allows the end effector and the grip portion to shift relatively without maintaining the size of the gap between the end effector and the grip portion;
• acquiring, by an arm tip positional information acquisition unit, positional information on the end effector of the robot arm during the “teaching mode”;
• generating, by a desired trajectory generation unit, a desired trajectory of the end effector of the robot arm during the “teaching mode”, based on the arm tip positional information acquired by the arm tip positional information acquisition unit and the information on the relative position acquired by the relative positional information acquisition unit;
• and
• causing, by the control unit, the tracking control unit to perform tracking control on the robot arm moving in accordance with a teaching operation of the person when the mode switch unit switches to the “teaching mode”, and controlling, by the control unit, the robot arm in accordance with the desired trajectory generated by the desired trajectory generation unit when the mode switch unit switches to the “playback mode”.

An integrated electronic circuit of a robot arm, for controlling a motion of the robot arm including:

• an end effector attached to a main body of the robot arm touched and operated by a person and caused to perform a task;
• and a grip portion attached to the main body of the robot arm so as to be separated from the end effector with a gap of a predetermined size being provided therebetween, the grip portion being relatively shiftable with respect to the end effector and being gripped by the person during the operation,
• the integrated electronic circuit configured to:
• acquiring, by a relative positional information acquisition unit, information on a relative position of the grip portion with respect to the end effector during the operation;
• obtaining, by a tracking control unit, a shift amount of the robot arm in order to perform tracking control of shifting the robot arm in accordance with an amount of variation of a size of the gap between the end effector and the grip portion so that the information on the relative position acquired by the relative positional information acquisition unit is within a range of a predetermined threshold;
• control, by a control unit, the robot arm so as to shift in accordance with the amount of variation of the size of the gap between the end effector and the grip portion, based on the shift amount of the robot arm obtained by the tracking control unit;
• maintain the size of the gap between the end effector and the grip portion, by a fixing portion including a fixing member shiftable between a fixed position where the fixing member is in contact with the end effector and the grip portion to fix the end effector and the grip portion and restrict relative shift between the end effector and the grip portion, and an accommodated position where the fixed member is accommodated in the end effector or in the grip portion and allows the end effector and the grip portion to shift relatively, when the fixing member is located at the fixed position;
• switch, by a mode switch unit, between a “teaching mode” and a “playback mode” as a control mode of the robot arm;
• switch, by a fixing switch unit, between a fixing state where, when the mode switch unit switches to the “playback mode”, the fixing portion is located at the fixed position to fix the end effector and the grip portion and maintain the size of the gap between the end effector and the grip portion, and a relatively shiftable state where, when the mode switch unit switches to the “teaching mode”, the fixing portion is located at the accommodated position and allows the end effector and the grip portion to shift relatively without maintaining the size of the gap between the end effector and the grip portion;
• acquire, by an arm tip positional information acquisition unit, positional information on the end effector of the robot arm during the “teaching mode”;
• and
• generate, by a desired trajectory generation unit, a desired trajectory of the end effector of the robot arm during the “teaching mode”, based on the arm tip positional information acquired by the arm tip positional information acquisition unit and the information on the relative position acquired by the relative positional information acquisition unit, wherein
• the control unit causes the tracking control unit to perform tracking control on the robot arm moving in accordance with a teaching operation of the person when the mode switch unit switches to the “teaching mode”, and controls the robot arm in accordance with the desired trajectory generated by the desired trajectory generation unit when the mode switch unit switches to the “playback mode”.