Research On Decentralized Interactive Control Of Reconfigurable Robots Based On Joint Torque Estimation

Reconfigurable robots can recombine and configure their own configurations according to different task requirements and working environments,thus showing many advantages that traditional robots do not have." reconfigurable " and " Modular " are the two basic properties for reconfigurable robot design.The main idea is to decompose a complex robot system into multiple subsystems with high portability and maintainability.Shorten the design and manufacturing cycle of the robot system effectively.It is inevitable for reconfigurable robot to complete its work in an uncertain environment,and the stability,robustness,accuracy as well as other indicators of the system should be comprehensively considered and ensured,so that it is necessary to design appropriate control laws for the above situations.This paper focuses on the following research for reconfigurable robots:(1)Robot joint torque estimation based on harmonic drive flexible modelIn order to achieve high control accuracy for reconfigurable robot systems,it is necessary to consider the compensation of the constraints and load force of the robot joints.Joint torque estimation technology is considered to be an effective way to solve this problem.In order to obtain joint torque without using torque sensor,a joint moment estimation method is introduced based on the improved nonlinear harmonic drive model.Considering the flexibility of wave generator and flexspline,the kinematics error of harmonic drive and the torque deviation,estimated the joint torque by only using the position measurement data acquired by the encoders at the motor side and the end of joint.Moreover,the applicability of this method is verified by experiments.(2)Dynamic model of harmonic drive-based reconfigurable robots with joint torque estimationThis paper introduces the kinematic relationship and torque transmission principle of the harmonic drive,which is an important component of the reconfigurable robot joint module,and established a mathematical model based on the flexibility of harmonic drive.The disturbance torque transmission of harmonic drive and the measurement error of sensor are taken into account.Combined the idea of reconfiguration,the dynamic model of reconfigurable robot system is established based on joint torque estimation technology.(3)Decentralized interactive control of reconfigurable robot based on joint torque estimationDecentralized control method decomposes the complex dynamics model of robot into multiple coupled subsystems,and designed the local controller to compensate the uncertainties and coupling effects of the subsystem model simultaneously.The advantage of the method is reducing the complexity of the control system from the whole system level to the decentralized level,which greatly simplifies the complexity of the controller and effectively improves the computation speed.In this paper,the joint torque estimation is used to realize the decentralized interactive control of reconfigurable robot based on joint torque estimation.The controller also uses neural network to estimate and compensate the uncertainty of the robot model,which achieves high-precision control effect.When the reconfigurable robot is impacted by external collisions,the robust algorithm is applied to the decentralized control,which makes the robot system run smoothly.The stability of the controller is proved by Lyapunov stability analysis method.Finally,the effectiveness of the controller is verified by experiments.(4)Decentralized active disturbance rejection interactive control for reconfigurable robot under uncertain environmentsIn the practical application of reconfigurable robot,uncertain task environments are worth considering.According to the physical human-robot interaction and collision,through the analysis of the reconfigurable robot in the previous chapters,the dynamic model of each joint subsystem of the reconfigurable robot is established.Based on the design of extended state observer and terminal sliding mode,the decentralized active disturbance rejection control algorithm for reconfigurable robot under uncertain task environment is proposed.Under the condition of model uncertainty and interconnected dynamic coupling between joint subsystems,the robot can track the desired trajectory of joint in uncertain environment,ensure the stability of extended state observer and closed-loop system,as well as the trajectory tracking error can converge to zero in finite time,so as to achieve high-precision control effect.The stability of the controller is proved by Lyapunov stability analysis method.Finally,the effectiveness of the controller is verified by experimental research on Quanser robot platform.