Research On Attitude Tracking Fault-tolerant Control Of A Two-degree-of-freedom Helicopte

As scientific and technological advances continue to develop,the field of transportation is also moving towards intelligence.In this development process,unmanned helicopters play an important role in tasks such as monitoring,information collection and dissemination.However,unmanned helicopters face complex and ever-changing environmental factors during task execution,and in the event of a malfunction,may cause irreparable consequences.Therefore,ensuring the flight stability and safety of unmanned helicopters in the event of a failure is of great significance for improving the application level of unmanned helicopters in the field of transportation.This paper takes the two-degree-of-freedom helicopter produced by Quanser as the research object and designs a fault-tolerant controller based on the sliding mode control algorithm for its actuator and sensor failures.The controller uses an observer for fault estimation and real-time compensation to ensure that the helicopter can maintain a stable flight attitude in the event of a failure.The research contents of this paper mainly include:(1)Based on the system model of the two-degree-of-freedom helicopter,using the Riemann-Liouville theorem of the β-order derivative and the sliding mode control method,a finite-time fractional sliding mode controller is designed.The controller can effectively reduce the chattering effect of the sliding mode controller and ensure that the system state reaches the equilibrium point within a finite time.In addition,considering the possibility of actuator failures in the two-degree-of-freedom helicopter,an actuator fault model is established,and a neural network observer is used to detect the fault value of the actuator in real time,which is then compensated into the finite-time fractional sliding mode controller.Finally,the effectiveness of the designed fault-tolerant control algorithm is verified in simulation and experiments.(2)Based on the system model of the two-degree-of-freedom helicopter,a control strategy based on interval type-2 fuzzy sliding mode method is proposed.This control strategy combines fuzzy logic control algorithm and sliding mode control algorithm,which can effectively reduce the system chattering.Meanwhile,considering the possibility of sensor failures in the two-degree-of-freedom helicopter,a sensor fault model is established,and an adaptive observer is used to estimate the sensor fault value.According to the estimated fault value,a new sliding surface is obtained using the Lyapunov function,and a fault-tolerant controller is reconstructed for the interval type-2 fuzzy sliding mode controller.Finally,the effectiveness of the designed fault-tolerant control algorithm is verified in simulation and experiments.