Robust Adaptive Control Of Flexible Manipulator For Express Delivery Sortin

In courier sorting,the automation process of sorting is being enhanced as the business volume increases year by year.Robotic arms play an important role in improving sorting efficiency.Flexible manipulators have the advantages of low energy consumption and high flexibility compared to traditional rigid manipulator arms,and are therefore increasingly used in express sorting.However,due to the flexibility of the constituent materials,large deformations and elastic vibrations are inevitably generated during the execution process,affecting the positioning accuracy of the flexible manipulators’ performing sorting work.In addition,the input nonlinearity and communication constraint in the system will affect the input control signal,so that its control role can’t be fully performed,reducing the control accuracy and sorting efficiency of the system.In this paper,we analyze the input nonlinearity and communication constraints in the system,and develop a robust adaptive control algorithm to achieve the vibration suppression and trajectory tracking of the system,so as to improve the sorting accuracy and efficiency of the flexible manipulator.The main contents include:(1)For the unknown dead zone in the system,the nonlinear model is deconstructed,the estimation variables are designed with adaptive iterative laws to estimate the unknown parameters of the dead zone,and the adverse effects of the dead zone are eliminated in the controller design to reduce the steady-state error of the system sorting and positioning.(2)Considering the existence of dead zone and input quantization in the system,the hysteresis quantizer is applied to simulate the quantization process of the signal,the coupling effect of dead zone and input quantization is analyzed,and the quantization error is eliminated in the controller design,thus enabling the system to maintain sufficient control accuracy at low communication rates when performing sorted express.(3)When input saturation exists in the system,the hyperbolic tangent function is applied to describe the nonlinear model of input saturation,and the controller design is based on the backstepping method with the Nussbaum function to compensate for the saturation nonlinearity,avoid the chattering phenomenon of the control signal,and ensure that the system can perform the sorting work stably and quickly even under the input amplitude limitation.For the designed control strategy,this paper will theoretically apply Lyapunov direct method for stability analysis to ensure the boundedness of the system state.Numerical simulation of the system operation is performed using Matlab software,while experiments are carried out on a flexible link control platform developed by Quanser.Other control strategies are introduced for comparison to observe the execution effect of the designed strategy,thus verifying the effectiveness and practicality of the designed control strategy.