Fault Tolerant Control Of Quadrotors With Prescribed Performance Constraints

Due to its compact body,convenient operation,low cost and strong environmental adaptability,quadrotors have been greatly applied and popularized in various aspects of human life such as aerial photography,unmanned delivery,reconnaissance and detection.However,there are many safety and stability challenges in the actual application of quadrotors.In the actual control of quadrotors,actuators,sensors,and other communication or connection mechanisms have the possibility of failure during operation.For the safety and stability of the quadrotors control,how to deal with possible failures and ensure the transient and steady state performance of the system is particularly important.This paper conducts related research on the prescribed performance and fault-tolerant control of quadrotors with actuator failures.(1)Adaptive prescribed performance control strategy for quadrotors with actuator failures.Firstly,the actuator fault is modeled and analyzed.A simplified model of a quadrotors with actuator failure is established,based on the closed-loop control strategy of inner loop attitude control and outer loop position control,the quadrotors system is decoupled into a position subsystem and an attitude subsystem.Secondly,an adaptive control scheme is designed.The adaptive estimation of the existing actuator failure parameters effectively solves the stability control problem of the quadrotors under the actuator failure.Furthermore,a prescribed performance control strategy is proposed to ensure that the transient and steady state performance of the system meets the prescribed performance index.(2)Based on the adaptive prescribed performance control of quadrotors with actuator failure,another fixed-time prescribed performance control scheme is proposed.Based on the previous research,considering that the traditional prescribed performance function can use the error conversion method,when the time tends to infinity,the tracking error will converge to the prescribed range.Although the stability of the system can be effectively adjusted,The larger the initial value,the slower the rate of convergence.In response to this problem,a new fixed-time prescribed performance function is adopted to achieve the stability control of a quadrotors with a fault in fixed-time,and the effectiveness of the control method is verified by simulation.(3)A fixed-time prescribed performance control scheme is designed for the quadrotors with sensor failures.Firstly,the sensor fault is modeled and analyzed.A simplified model of a quadrotors with sensor failure is established,based on the closed-loop control strategy of inner loop attitude control and outer loop position control,the quadrotors system is decoupled into a position subsystem and an attitude subsystem.Secondly,an adaptive control scheme is designed to adaptively estimate sensor fault parameters,which effectively solves the problem of quadrotors fault-tolerant control under sensor faults.Furthermore,a fixed-time prescribed performance control strategy is proposed to ensure that the transient and steady state performance of the system meets the prescribed performance index and can converge in fixed-time.