Integrated Dynamic Modeling for a Stewart Platform

Abstract

This work is to study the integrated dynamic modeling for a Stewart platform from the control point of view. A general Stewart platform is composed of moving platform, fixed platform, connecting rod (actuator) and joint hinge. The kinematic inverse solution can accurately reflect the relationship between the connecting rod length and the position and orientation of the moving platform. As a highlight, this approach takes into account the moving platform's mechanical model and the actuator's electrical model respectively. We can apply the Newton-Euler method to the moving platform's force analysis to obtain the dynamic mechanical model. In this paper, the voice coil motor is chosen as the actuator due to its advantages of fast response, frequency bandwidth, and mature technology. According to the Jacobian matrix, which can describe the transmission of joints, we connect the actuator's electrical model to the mechanical model of the moving platform. In this way, the singularity of the parallel mechanism could be judged by the controllability of the integrated model. The integrated modeling not only establishes a direct connection between the control input and the task-space, but gives the way of singularity discrimination from the control point of view.