The Design of Control System for Motion Platform based PLC

In this paper, a new-style platform control system with three degree of freedoms: up-down motion, left-right rolling and front-rear pitching is designed,and also its composition, operating principle and soft design method are introduced. The system is driven by air cylinder and consists of FX series PLC, AD module, DA module, proportional valves, sliding rheostats and so on. Among these modules, sliding rheostats works as a feedback component to comprise a closed loop. Furthermore, to ensure the high positioning precision, the "PID" algorithm is applied. In addition, to control the motion flow reliably, the ladder logic diagram of the turn-off prior to turn-on is used to replace Sequential Function Chart. Experiments show that the motion platform is steady and safety when the proportional valves and directional valves are controlled by PLC.