Adaptive robust synchronous control of a individual metering dual-cylinder pneumatic system with composite parallel method

There are large extents of parametric uncertainties and uncertain nonlinearities in the inherent nonlinear dynamics of a dual-cylinder pneumatic system, and there are two separate control degrees of freedom for each pneumatic cylinder due to individual metering, which results in great challenges in precision synchronization motion and brings about flexibility in controller design. In this paper, a synchronous control of the individual pneumatic system is synthesized through introducing composite errors of synchronous and individual tracking motion into two independent parallel adaptive robust motion controllers for one-side chamber of pneumatic cylinder. Simultaneously, an adaptive robust pressure controller for the other-side chamber of each cylinder is presented to keep stable influences of friction force and other uncertainties. The effects of synchronous coefficient upon synchronization performance are extensively analyzed. Simulations results demonstrated that the proposed adaptive robust synchronous control with composite parallel method can significantly decrease synchronous error and individual tracking error compare to synchronous control with pure parallel method that without cross-coupling feedback of synchronous error.