Vibration control on linear robots with digital servocompensator

This paper presents the results of a digital vibration control strategy for high speed robots used by the NIST ATP Precision Optoelectronics Assembly Consortium. In this project, the goal is to develop high speed assembly platform to achieve 0.1 μm linear tolerance. However, as the robot's acceleration may reach 3g, rapid slewing motion inevitably excites the structural resonance of the mechanical members of the robot and degrades the performance of the system. The robust servomechanism problem is implemented digitally to suppress these vibration modes. The performance of the servocompensator is measured by comparing the frequency response of the plant in open loop to that with the servocompensator running. Typically, about 40dB of attenuation is achieved in the amplitude of the targeted mode. Suppression of vibration up to seven modes have been implemented satisfactorily.