Control of hybrid machines with-2-DOF for trajectory tracking problems

There are two types of drivers in production machine systems: constant velocity (CV) motor and servo-motor. If a system contains two drivers or more, among which some are of the CV motor while the other are the servo-motor, the system has the so-called hybrid driver architecture and is called hybrid machine for short. The hybrid system has the advantage of high payload and application flexibility. In this brief, we propose a control algorithm and show that the controlled hybrid machine is stable. A simulation is performed to verify the proposed controller. The CV motor has the velocity fluctuation due to the change of its workload. The common approach to attenuate the velocity fluctuation is via a flywheel which is attached on the shaft of the CV motor. We show that this can further improve the tracking performance of the hybrid system. A five-bar linkage with two degrees of freedom is used for illustration throughout the brief.