This grant provides funding for the development of high bandwidth fast actuators and control for machining applications. The fast tool servos will be used to machine software programmed deterministic surfaces and compensate for dynamic errors occurred in the process. The research will first develop an innovative fast actuator, which combines dual-stage solid state actuators with fluid power transmission for high bandwidth actuation in a compact package. Multivariable linear robust performance control design method, which incorporates repetitive control, previewed feedforward control, and the effect of the cutting force in a unified feedback control formulation, will be developed for the actuator to precisely generate dynamic trajectories. To realize the fastest possible actuator response so that a fine feature may be machined, switching control for pulse width modulation will also be investigated. Machining experiment will be conducted to test the actuator and control capabilities. In particular, the fast tool servos will be used to generate non-circular engine cylinder bore shapes for compensating cylindrical errors and surface texture to provide improved cylinder-piston fit and tribology conditions, thereby reducing emission, increasing fuel economy, and simplifying manufacturing processes.
If successful, the results of this research will lead to improvements in the speed, accuracy, and consistency of machining such irregularly shaped parts as engine piston profiles, piston pin holes, and cylinder bores. Potentially the proposed work could also be applied to machining deterministic tribology surface in parts like journal bearings, linear guide ways, and hydraulic valves/cylinders. The proposed work also contribute in the general motion control field. The proposed actuator and control design methods may contribute to extend the motion control performance and find new applications besides machining.
