Research On Active Disturbance Rejection Control Algorithm And Its Application In Robot System

In this paper,the traditional ADRC algorithm is improved,and the stability of the improved algorithm is proved.The ADRC algorithm is applied to the first-order system and the second-order system respectively.The simulation and experiment indicate the effectiveness of the ADRC algorithm.Firstly,as high-gain linear extended state observer(LESO)will cause initial peak value,an improved linear active disturbance rejection control(LADRC)strategy is proposed to optimize the control performance.For low-order systems,disturbance compensation is limited using saturation function in the inner loop.Meanwhile the output feedback is adopted in the outer loop.The improved LADRC is shown to be bounded input bounded output(BIBO)under certain conditions.In addition,LADRC is applied to an inverted pendulum in simulation.Tuning methods are proposed for the upper and lower limits of the saturation function and the compensation factor.Secondly,in order to further explain the physical significance of the parameters in the LADRC algorithm and verify the effectiveness of the algorithm,the LADRC algorithm is applied to a first-order controlled object--lower limb rehabilitation robot.A lower limb rehabilitation robot was designed according to the information of the range of motion of human lower limbs.The kinematics and dynamics models of the lower limb rehabilitation robot were established,and then the speed active disturbance rejection controller was designed.The simulation model was built and a series of simulation operations were carried out.A prototype of rehabilitation robot was produced and experimented.The improved LADRC method can meet the control requirements of the rehabilitation robot.Finally,in order to illustrate the generality of the LADRC algorithm,the LADRC algorithm is applied to a more common second-order system--the joint control of a biped walking robot.The kinematics model of the single leg of the existing biped walking robot in the laboratory was established,and the gravity of some joints was compensated.The simulation and experiment of single joint control and multi-joint linkage control are carried out successively.After applying the LADRC algorithm to other joints of the robot,the standing balance experiment of the robot was carried out.The LADRC algorithm can realize the initial control of the robot.