Design and validation of an FPGA-based self-healing controller for hybrid machine tools

摘要

It has been recognised that the ability of dynamic reconfiguration and parallel computation for field programmable gate array (FPGA) provides significant advantages, particularly for increasing reliability and maintainability of electromechanical products. An FPGA-based self-healing controller for hybrid machine tools (HMTs) is developed to meet the high speed sampling rate requirement and a circuit of self-healing controllers as well as velocity profile generators for HMTs is designed using the very high speed integrated circuit hardware description language (VHDL) and implemented with an FPGA. A self-healing controller framework for HMTs is proposed and incorrectly measured leg position faults (LPFs) and incorrectly measured leg velocity faults (LVFs) are considered as examples. Faults are detected by fault detection and isolation (FDI) module considering the closed-loop kinematic chain constrains of spatial hybrid mechanism utilising a sensored passive leg. When a fault is detected, the control system and the desired joint space trajectory are reconfigured according to the nature of the isolated fault and the task is resumed to the largest extent possibility. Feasibility and performance of above self-healing controller are validated by experiments and simulation examples.