面向并联机器人传感器故障的容错纠错策略、算法及其FPGA实现

【作者】 陈晓东；

【导师】 范守文；

【作者基本信息】 电子科技大学 ， 机械设计及理论， 2010， 硕士

【摘要】 容错纠错技术是提高机电产品安全性、可靠性的有效手段。本文以四自由度2RPS+2TPS型并联机器人传感器故障的容错纠错策略、重构算法及其现场可编程门阵列(Field Programmable Gate Array,FPGA)实现技术的研究为主线,对上述研究内容进行了较为深入系统的研究。针对2RPS+2TPS型四自由度并联机器人可能出现的传感器故障提出了一种容错纠错策略,该策略通过在机器人的固定平台和动平台中心附加一柔索,柔索一端连接弹簧和冗余传感器,实现了对机器人四条驱动腿传感器故障的容错纠错功能。如果驱动腿中的某一个传感器发生故障,则可根据空间闭链机构约束,由其它正常工作驱动腿的传感器和冗余传感器的测量值计算出故障传感器的应测值,文中导出了位移和速度传感器故障的容错纠错重构算法。通过模拟渐变型和突变型的传感器故障,对文中提出的容错纠错方案进行了仿真研究。对位移传感器故障容错纠错重构算法的FPGA实现技术进行了研究,针对重构算法中的复杂数学运算,应用了CORDIC、Chebyshev等易于用FPGA实现的算法来求解,对各种复杂运算的FPGA实现技术进行了研究,以位移重构算法的FPGA实现为实例,用多组数据进行了仿真验证。基于胚胎细胞的可重构特性,提出了一种自修复机制,对重构算法的FPGA数字电路的容错纠错方法进行了研究,设计了基本结构单元,应用实例分析了该数字电路的自修复机理,通过对比研究验证了该方法能有效提高FPGA系统的容错性能。提出了基于FPGA实现位移传感器故障容错重构实验的整体架构及实验验证方法步骤。对容错重构实验中重构算法、控制系统及故障检测与隔离三大功能的FPGA的系统结构进行了设计,研究了FPGA实现直流伺服电机PID控制的结构和电路,并通过了实验验证。本论文研究的并联机器人传感器故障的容错纠错策略、算法及其FPGA实现技术将为其它机电产品的容错纠错提供了有价值的借鉴和指导。更多还原

【Abstract】 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.更多还原