Predefined-Time Fault-Tolerant Control for Active Vehicle Suspension Systems With Reference X-Dynamics and Conditional Disturbance Cancellation

Active vehicle suspension systems exhibit substantial vibration isolation capabilities, however, suffer from external disturbances, high energy consumption, risks of fault signals, limited transient performance, etc. In this paper, a predefined-time fault-tolerant control scheme is proposed for active suspensions to improve ride comfort and reliability, and enhance energy conservation. The reference X-dynamics together with a conditional disturbance cancellation scheme are developed to avoid the cancellation of beneficial nonlinearities and beneficial disturbances, respectively, which can reduce energy consumption without any optimization calculation or hardware alteration. Importantly, the error signals can converge to a predefined bound within the predefined time interval. Both the settling time and the residual bound can be arbitrarily user-defined, which are independent of initial states and control gains. Especially, to avoid singularity and alleviate chattering, a continuous piecewise function and a quadratic fraction inequality are constructed. The utilization of the proposed predefined-time fault-tolerant control facilitates satisfactory ride comfort with low energy cost. Experimental results are presented to validate the superior control performance of the designed control scheme.