Design and Position & Gesture Matrix Expression of 3-DOF Wrist of Two-color Sole Molding Robot

In the multi-color sole molding process, multiple robots instead of manual operation are used. The robot end-effector must complete the serial action of mold closing, residual material cleaning, mold opening, inspecting and up-picking of the work as the main functions and techniques. In this paper, based on the new technological process of the sole injection, robot logical action sequence, and functional requirements and mechanism theory, a wrist compact in structure and independent in motion with three degrees of freedom was designed. According to the new molding process, the three end-effectors, namely, the opening and closing actuator, the flapping residual material cleaning actuator, and the inspection and picking actuator, were connected with the wrist after logic induction and integration of action functions. By setting the local coordinate system and the global coordinate system, the unified matrix expression describing the position of the base, the arm and the wrist reference points and the gestures of three end-effectors was developed, so that the robot's action function is fully matched with the multi-color sole molding process requirements of the robot replacing the operator. Such expression provides effective methods and means for further research, test and optimization of wrist and robot systems.