Multichannel Asynchronous Triggering-Based Adaptive Output Feedback Control for Uncertain Nonlinear Systems with Actuator Faults
Authors: Xinpeng Fang, Huijin Fan, Lei Liu, Bo Wang
Extended abstract:
For a control system, the control commands need to be executed accurately by the actuator. However, harsh environments and aging hardware may cause actuator faults. As a consequence, the designed control commands cannot be executed correctly, and the control performance may be degraded. Meanwhile, in practical systems, signals are usually transmitted among different components through networks with limited bandwidth. Therefore, tolerating actuator faults while reducing resource consumption can significantly contribute to the safety enhancement and lifespan extension of the system. This paper proposes an adaptive event-triggered output feedback fault-tolerant control scheme for a class of uncertain nonlinear systems with unknown actuator faults. Multiple channels, including the state estimation filter-to-controller (S-C) channel, the parameter estimator-to-controller (P-C) channel and the controller-to-actuator (C-A) channel, are all event-triggered. Moreover, by designing a series of uncorrelated triggering conditions, the triggering of different channels is independent and asynchronous. The advantages of the proposed triggering mechanism are to 1) reduce the communication burden for multiple types of channels by decreasing the signal transmission frequency, and 2) reduce the computation burden by removing real-time integration. Therefore, the communication and computation burden of the system can be released. Meanwhile, the signal transmission frequency of each channel can be adjusted independently. It is proved rigorously that, with our proposed control scheme, all the closed-loop signals are bounded and the output tracking error converges into an adjustable residual set. Also, the Zeno behavior can be excluded. Finally, the scheme is applied to a robot manipulator and the simulation results illustrate the effectiveness of the proposed control scheme.
