Dynamics of dual-drive servo mechanism

Gantry mechanisms are widely used for precision manufacturing and material handling in electronics, nuclear, and automotive industries. Dual drive servo mechanism is a way to increase control bandwidth, in which two primary axes aligned in parallel are synchronously driven by identical servo motors. With this mechanism, a flexible coupling is often introduced in order to avoid the damage by the servo mismatch between the dual drives located at each side of gantry. This paper describes the dynamics of this mechanism including the flexible joints and discusses its control ramifications. Also, under the assumption of no servo mismatch between the two drives, simulations are performed to analyze the dynamic effect of the mass of end-effector. Based on the simulation results, an appropriate design guideline to increase the servo bandwidth and to reduce position errors is suggested.