Sensory Configuration of Stewart Platform-A Numerical Study

Stewart mechanisms or hexapods are mainly used in actuation and three dimensional motion simulators. However, three dimensional position of any object on the movable platform could be recognized based on the six leg variable lengths which their tasks have altered to displacement sensors. The mentioned configuration will have application in test benches and determining the rational positions of two planes which are attached to the moveable and fix platforms. This configuration of Stewart platforms involves in forward dynamics problem and often requires challenging calculation procedure. In this research, a method based on the geometrical constraints of the configuration is developed and a system of nine nonlinear equations is solved using Newton-Raphson iterative procedure. Sensitivity of proposed procedure to initial conditions and its performance in predicting the position of the platform is investigated. Effect of initial conditions’ updating in expediting the numerical algorithmconvergence is also studied.

Keywords:

Hexapod , Position Sensor , Stewart platform , Forward dynamics.