Global Modal Space Control for a Hydraulically Driven Stewart Platform

This paper presents a global modal space controller for hydraulically driven Stewart platforms that has high control performance in a large overall workspace. The relationship between the modes and the platform position is analyzed employing perturbation theory. According to the principle of mode relativity, a new real-time mode-tracing algorithm is developed to resolve the mode-jumping phenomenon in the global workspace. Applying the proposed algorithm and combining dynamic pressure feedback correction, the global modal space controller of the parallel manipulator is estimated. Experimental results show the proposed controller has good performance and can broaden the bandwidth in the global workspace.