Fault-tolerant Error Correction Strategies For Parallel Robot Sensor Failure, And Its Fpga Implementation

Fault tolerance and fault rectification technologies are effective approaches for enhancing reliability and safety of electro-mechanical products(EMPs). Fault tolerance and fault rectification strategy, reconfiguration algorithm and its field programmable gate array (FPGA) implementation technology for 2RPS+2TPS type parallel manipulators are taken as the main clue, above research contents are studied deeply and systemly in this paper.A fault tolerance and fault rectification strategy for sensor faults of 2RPS+2TPS type parallel manipulators is presented in this paper, in this strategy, a flexible cable is attached between the center of fixed platform and the center of movable platform, and spring and redundant sensor are connected to one end of the flexible cable. If fault occurs in one of the four driving legs'sensors, the real value of fault sensor can be computed by the detected value of the other three driving legs'sensors and the redundant sensor utilizing spatial closed chain constrain relationship, corresponding algorithms of fault tolerance reconfiguration for displacement sensors and velocity sensors are deduced, simulation researches for fault tolerance and fault rectification performance of above strategy are conducted by emulation of a gradual type sensor fault and a abrupt type sensor fault, simulation results show that the fault tolerance and fault rectification strategy proposed in this paper can guarantee the reliability and safety of parallel manipulators system effectively.FPGA implementation technology for fault tolerance reconfiguration algorithm of displacement sensor fault in parallel manipulators is studied in this paper, CORDIC algorithm and Chebyshev algorithm are utilized to implement complex mathematic computation in FPGA, the implementation of displacement reconfiguration algorithm for parallel manipulators is taken as examples, simulation verification is conducted for several group datas.Based on reconfiguration property of embryo cells, a self-healing mechanism is presented in this paper, fault tolerance and fault rectification methodology for FPGA digital circuit of reconfiguration algorithm is studied, basic structure cell is designed, self-healing mechanism for above digital circuit is analyzed using examples, contrast researches demonstrate that above methodology can enhance the fault tolerance performance of FPGA system effectively.Experiment framework, experiment methodology and experiment step of fault tolerance reconfiguration for sensor fault of parallel manipulators are presented in this paper. FPGA system structures of three main function modules for above experiment, including reconfiguration algorithm, control system and fault detection and isolation, are designed, the implementation of a PID controller for DC servo motors based on FPGA is studied, experiments are carried out to validate the FPGA based PID controller.The fault tolerance and fault rectification strategy, reconfiguration algorithm and its FPGA implementation technology for parallel manipulators presented in this paper will provide valuable reference and guidance for the fault tolerance and fault rectification of the other EMPs.