Vibration Analysis of Tendon-Based Parallel Robot for Processing

The vibration characteristics of the tendon-based parallel robot for processing are presented. Firstly, the free vibration equations of the robot on the stable position and orientation were modeled, and secondly the natural frequencies were deduced from the transformation of principal coordinates into modal coordinates. Next, cutting-force model was introduced and the solutions of the forced vibration equations were obtained from the Runge-Kutta method, where the minimum natural frequency was taken as basis of the time step that was important for computation convergence. Lastly, the algorithm was verified by simulations, also including solution transformation of time domain into frequency domain by Fast Fourier Transformation (FFT). The vibration properties could be manifested clearly by the solutions in frequency domain. The results show that the eccentricity and the mass of the moving platform are the important factors to make system instable in certain excitation frequency.