Control of a pneumatically actuated 6-DOF Gough-Stewart platform

This paper addresses the control of a pneumatically actuated Gough-Stewart platform with Six Degrees-of-Freedom. The platform understudy has six links for which each link contains one linear potentiometer, for the exact position of link, two pressure indicators, for input and output pressures of the jack, and one valve to adjust the air flow. The orientation and position of the moving platform are prescribed as the trajectory of the end-effector and using Inverse Kinematic Problem (IKP) the length of each link one obtained. Then air flow rate of each valve and rate of air pressure passing over each cylinder have been modelled based on displacement of each piston. Subsequently, changing the input voltage of the valves, the air flow rates and the displacement of each link have been controlled. In this study, PI controller is used and position errors are less than 0.01 inch.