Dynamic Analysis of Stewart platform Using Sim Mechanics

Abstract

In this work, the dynamic analysis of Stewart platform using SimMechanics is presented. Stewart platform is a positioning system that consists of moving or top plate, a fixed or bottom plate and six extensible legs connecting the two plates. The model is developed in SimMechanics using spherical joints. The axial rotation of the legs is constrained. The work includes modelling and dynamics analysis of a complete positioning system. Firstly, the physical plant of Stewart platform is developed in SimMechanics environment. The physical plant contains leg subsystem, moving plate and fixed plate which is grounded. For controlling the trajectory a PID controller is attached to the physical plant. The given inputs to the leg trajectory in the form of position and orientation of the legs are in sinusoidal form. The reference position is obtained as output and fed to controller. The output of the controller is applied to the physical plant as actuating force, which controls the motion of Stewart platform. The simulation results include position of the body, the error in length and the leg forces.