Finite-Time Command Filter Inversion Control Of Flexible Articulated Robotic Arm

Because of its advantages of high production efficiency,reasonable price and strong adaptability to the environment,robotic arms have been widely used in aerospace,industrial manufacturing,textile and garment industries.However,due to its rigid structure,it is difficult to ensure the safety of system interaction during operation.Flexible joint manipulator can provide flexible movement,and at the same time has the advantages of light weight,low material energy consumption and small inertia,and has a wide range of application prospects in medical rehabilitation,daily life and other fields.However,the introduction of flexible joints will inevitably cause elastic vibration of the robotic arm,which will affect the control accuracy.In this thesis,taking the tracking control of flexible joint manipulator arm as the research object,the fixed threshold event trigger command filter inversion control,the adaptive threshold event trigger fast finite time command filter inversion control and the finite time command filter fault tolerance control are proposed.The specific research content is as follows:Firstly,taking the tracking control of flexible joint manipulator as the research goal,a design method of fixed threshold command filter inversion controller considering error compensation is proposed.This method uses the second-order command filter to calculate the virtual control law differentiation,which solves the explosion problem in traditional inversion control.In order to reduce the communication burden of the controller,a fixed threshold event is introduced to trigger the control strategy;Next,the Lyapunov function is constructed using the compensated tracking error to prove the stability of the controller.Secondly,in order to further improve the convergence speed of the controller and reduce the communication bandwidth,an adaptive threshold event trigger fast finite time command filtering inversion controller is proposed.In order to improve the response speed and approximation accuracy of the command filter,the command filter is designed by replacing the traditional second-order filter with a fast and accurate differential with global convergence.Combining finite time control and adaptive threshold event triggering two control strategies,a fast finite time adaptive threshold event triggering attitude tracking control is designed.The design scheme allows the tracking error of the system to converge in an arbitrarily small neighborhood from the origin within a limited time,and the output variable can track the desired output signal in a limited time,and the tracking error is located in a small neighborhood at the origin.At the same time,the differential explosion problem in traditional inversion control is solved by command filtering technology.Finally,the simulation results prove the effectiveness of the proposed algorithm.Finally,aiming at the problem of flexible joint manipulator control under fixed bias fault and failure fault of sensor,a fault-tolerant control strategy of finite time command filtering is proposed.The fuzzy logic reasoning system is used to deal with the unknown function in the sensor fault,and the Lyapunov function is constructed by combining the control strategies such as finite time control,command filter control,fault-tolerant control,and fuzzy control.Then,according to Lyapunov’s stability theorem,the stability analysis of the tracking system of flexible joint manipulator arm with sensor fault is carried out,which proves that the design scheme proposed in this thesis can ensure that the system is a semi-global finite time problem at the origin regardless of whether it fails or not.