Fault Diagnosis And Fault Tolerant Control For Manipulators Cooperation System

With the development of technology,modern industrial production has become more and more complicated.With its advantages of high production efficiency and good safety,the manipulator plays a key role in industrial production and gradually replaces manpower as the main productive force.A single manipulator is inefficient and has a single function that does not meet production needs,but the cooperation of multiple manipulators can overcome these shortcomings.When the fault occurs in the multiple manipulator system,it will not only affect its own control effect,but also affect other manipulators,causing loss of human and material resources,and even threatening personal safety.Therefore,it is especially important to obtain the fault information of the multi-manipulator system in time and perform fault-tolerant control.The multi-manipulator system is a complex system consisting of multiple sub-manipulator systems.When an actuator or sensor fault occurs in a multimanipulator system,fault diagnosis and fault-tolerant control are more difficult.In this paper,we design the observer to obtain the estimated value of the fault in time,and design a fault-tolerant controller which contains the fault information.Ensure that even if a fault occurs,the system output can still reach the desired value under the action of the fault-tolerant controller.In this thesis,fault diagnosis and fault tolerant control of the multi-manipulator cooperative system is studied.The main contents are shown as follows:(1)Fault diagnosis and fault tolerant control of a single manipulator system is studied.The dynamic model of the manipulator is taken as the research object,and the influence of disturbance is considered.In the manipulator system,the drive motor is an actuator that controls the trajectory of the manipulator.When the fault occurs in the actuator,the adaptive observer is designed to diagnosis the fault.The adaptive parameters of the observer can be obtained by solving the corresponding linear matrix inequality.After obtaining the fault information,a sliding mode fault-tolerant controller is designed.When the fault occurs,the manipulator can still track the desired trajectory.The stability of the manipulator system is proved by the Lyapunov theorem.Finally,the effectiveness of the proposed control algorithm is verified by computer simulation.(2)Fault diagnosis and fault tolerant control of the cooperative system composed of two manipulators is studied.When two manipulators are used for part assembly or hole shaft fit,the output of two manipulators needs to meet the objective function.The cooperation task cannot be completed when the fault occurs.For such systems,the new idea of cooperative fault tolerant control of two manipulators is adopted.It is assumed that a multiplicative actuator fault occurs in the first manipulator subsystem,which does not have the ability of fault tolerant control.An adaptive fault diagnosis observer is designed to estimate the size of the fault.The fault-tolerant controller is designed in the second manipulator subsystem.The controller contains the fault estimation information of the first manipulator subsystem,so that the output of two manipulators still satisfies the objective function after the fault occurs.Numerical simulations demonstrate the effectiveness of the proposed algorithm.(3)Fault diagnosis and fault tolerant control of leader-follower based multiple manipulator collaboration system is studied,it is required that each follower manipulator can acquire the information of the leader manipulator when manipulators complete the synchronous control task.A learning observer is designed to obtain the fault information when a time-varying sensor fault occurs in the follower manipulator.Then,the fault-tolerant controller is designed for each follower manipulator,and the disturbance is approximated by the RBF neural network to ensure that the trajectory of the leader manipulator can still be tracked by the follower manipulator when the sensor fault occurs.Finally,the numerical simulation is used to verify the effectiveness of the manipulator coordination system fault-tolerant control algorithm.