A new numerical method for Stewart platform forward kinematics

This article proposes a numerical method based on equivalent model (NEM) for 6-3 Stewart platform forward kinematics problem (FKP). The NEM translates the forward kinematics problem into a ternary nonlinear equations system. Newton method was then used to solve the equations system. Simulations were conducted with different trajectories and allowable errors to compare the performance of NEM with traditional Newton-Raphson method (TNR). It turns out that NEM saves 50% iteration times, and 85% operation time of TNR, making the computing frequency as high as 54KHz, which is significant in real time control process. A practical structure of 6-3 Stewart platform without partial freedom was also designed.