Design of pressure control system for a large freeform surface polishing robot

A polishing implementing mechanism control system of a large freeform surface polishing robot is designed in this paper. According to the structure characteristic of the implementing mechanism, the control process is composed of position control process and pressure control process. The control system has overcome nonlinear characteristic of the proportional reducing valve effectively and ensured the implementing mechanism can start quickly by using the position and pressure closed loops. For the purpose that the robot can polish on a large freeform surface, a mathematic model of valve control cylinder system is established. The factor of influencing polishing pressure is analyzed. The PID control algorithm is used into the system with the position and pressure of cylinder as the signal of feedback. The experiments prove that this control system can achieve constant pressure polishing while the robot polishes with a certain velocity.