An intelligent control system for multiple degree-of-freedom vibration isolation

Multiple degree-of-freedom (DOF) vibration isolation and suppression capabilities are essential for precision control of a wide range of space-borne structures as well as earth-based systems. This paper presents the system design and implementation, control algorithms, parallel computing architecture, and real-time experiments of a six DOF Hexapod Active Vibration Isolation (HAVI) system developed at Intelligent Automation, Inc. The system design of the HAVI is based on the hexapod (Stewart Platform) concept. A novel geometric arrangement of a hexapod, called the ''Cubic Configuration'' is used. Magnetostrictive material Terfenol-D actuators are employed. A two-layer control system architecture incorporating local force feedback control and a robust adaptive filter control for active vibration isolation are employed. A high performance parallel computation engine MDSP-100 with multiple DSP processors and maximum 566 MFLOPs throughput is also developed for the HAVI applications and was used to implement proposed control algorithms. The unique architecture and functionality of the MDSP-100 facilitate the data acquisition and control law computation operations in a parallel computing fashion. Mechanical hardware for the HAVI system has been fabricated and tested. The six channel simultaneous active vibration control experiments were performed to demonstrate HAVI system's 6 DOF vibration isolation and suppression capabilities. A wide band (below 250 Hz) active vibration attenuation for all six channels was obtained in the real-time experiments.