Control device of robot arm and teaching system and method using the same

A robot arm teaching system, comprising:

• a pressure sensing module disposed on an operating portion of a robot arm and having a touch-sensing surface for detecting an operation command applied to the touch-sensing surface, wherein the touch-sensing surface comprises a first touch-sensing region and a second touch-sensing region, the first touch-sensing region is for defining a first reference coordinate system related to a translational motion mode, and the second touch-sensing region is for defining a second reference coordinate system related to a rotational motion mode;
• and
• a control module configured to receive at least a pressure sensing signal outputted by the pressure sensing module and to output a motor driving signal to the robot arm in response to the operation command, wherein the control module comprises:
• a joint-motor controller for generating a set of motor torque signals for moving the robot arm according to the operation command;
• a mode-switching module for switching operating modes of the robot arm, wherein the operating modes of the robot arm comprise a compliance teaching mode and a touch operating mode;
• and
• a plurality of joint-motor encoders disposed on each joint of the robot arm, wherein the joint-motor encoders generate a set of joint angle signals according to a moving trajectory of the robot arm under the compliance teaching mode;
• wherein, the control module controls the robot arm to move towards a target position according to the operation command.

A method for performing direct teaching on a robot arm, comprising:

• performing initialization on a robot arm and outputting a motor driving signal to the robot arm;
• recording a moving trajectory of the robot arm to obtain a current azimuth and posture of the robot arm;
• switching operating modes of the robot arm when the moving trajectory of the robot arm deviates from a target position, wherein the operating modes comprise a compliance teaching mode and a touch operating mode, wherein under the touch operating mode, a position control on an end effector of the robot arm is performed on the robot arm according to an operation command from a pressure sensing module;
• performing a joint posture control on the robot arm manually under the compliance teaching mode;
• correcting the moving trajectory of the robot arm by performing the position control on the end effector of the robot arm, or performing the position control on the end effector of the robot arm firstly and the joint posture control subsequently, or performing the joint posture control on the robot arm firstly and the position control on the end effector subsequently;
• terminating recording the moving trajectory of the robot arm;
• and
• reproducing a teaching trajectory of the robot arm to move the robot arm to the target position.