scholarly journals Investigation of feasible controller for position control of flexible joint manipulator using multiple control techniques

2019 ◽  
Vol 1 (12) ◽  
Author(s):  
Subodh Kumar ◽  
Kuldeep Jayaswal ◽  
D. P. Kothari
Keyword(s):  
Position Control ◽  
Multiple Control ◽  
Flexible Joint ◽  
Control Techniques ◽  
Flexible Joint Manipulator

A model-based PID-like motion control method for flexible-joint manipulator with harmonic drives

2021 ◽  
pp. 095440622110369
Author(s):  
Guocai Yang ◽  
Yechao Liu ◽  
Junhong Ji ◽  
Minghe Jin ◽  
Songhao Piao
Keyword(s):  
Position Control ◽  
Control Method ◽  
Joint Torque ◽  
Dynamics Model ◽  
Motion Error ◽  
Flexible Joint ◽  
Speed Range ◽  
Position Controller ◽  
Flexible Joint Manipulator ◽  
Better Than

A novel control method is proposed to achieve high trajectory tracking precision, for flexible-joint manipulators. The method consists of three major parts: joint torque generator, joint torque tracker and motor position controller. The expected torque is generated by a PID controller based on the manipulator’s rigid dynamics model. In the torque tracker, motor position is corrected in both feedback and feedforward ways. Finally, the motor position controller is responsible to track the corrected motor trajectory to achieve the torque and position control. To suppress nonlinear friction, a disturbance observer is also implemented. The method is verified with a seven-DOFs manipulator. Simulation and experimental results show that, the proposed method is efficient and practical to suppress vibration caused by flexible transmission and disturbance due to friction. As result, high positioning accuracy is achieved in a certain wide working speed range. The no-load motion accuracy is better than 0.6 mm with a manipulator whose length is 1.8 meter, and the motion error is less than 3 mm with loading of four kilograms.

scholarly journals Backstepping Controller for Electrically Driven Flexible Joint Manipulator Under Uncertainties

2015 ◽  
Vol 4 (2) ◽  
pp. 156
Author(s):  
Lilia Zouari ◽  
Hafedh Abid ◽  
Mohamed Abid
Keyword(s):  
Position Control ◽  
Current Control ◽  
Tracking Accuracy ◽  
Parameter Uncertainties ◽  
Flexible Joint ◽  
Brushless Dc ◽  
Hysteresis Controller ◽  
Bounded Disturbances ◽  
Backstepping Controller ◽  
Flexible Joint Manipulator

The grown complexity of the robot manipulators dynamics taking into account the jointflexibility, parameter uncertainties and unknown bounded disturbances makes conventionalcontrol strategies difficult and complex to synthesize. This paper focuses on the investiga-tion into backstepping control of flexible joint manipulator driving by Brushless DC Motor(BDCM) in the presence of parameter uncertainties and unknown bounded disturbances fortracking trajectory. The goal of this paper is to compensate all uncertainties and distur-bances for flexible joint manipulator. To study the effectiveness of the controllers, backstep-ping controller has been developed for position control and an hysteresis controller has beentreated for current control. Simulation results of the response of the flexible joint manipu-lators associated with their controllers have been presented. The high performances of thebackstepping control are examined in terms of tracking accuracy and error reduction.

Trajectory and Vibration Control of a Single-Link Flexible-Joint Manipulator Using a Distributed Higher-Order Differential Feedback Controller

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
John T. Agee ◽  
Zafer Bingul ◽  
Selcuk Kizir
Keyword(s):  
Trajectory Tracking ◽  
Higher Order ◽  
Feedback Controller ◽  
Step Response ◽  
Position Measurement ◽  
Tracking Errors ◽  
Flexible Joint ◽  
Nonminimum Phase ◽  
Step Input ◽  
Flexible Joint Manipulator

The trajectory tracking in the flexible-joint manipulator (FJM) system becomes complicated since the flexibility of the joint of the FJM superimposes vibrations and nonminimum phase characteristics. In this paper, a distributed higher-order differential feedback controller (DHODFC) using the link and joint position measurement was developed to reduce joint vibration in step input response and to improve tracking behavior in reference trajectory tracking control. In contrast to the classical higher-order differential (HOD), the dynamics of the joint and link are considered separately in DHODFC. In order to validate the performance of the DHODFC, step input, trajectory tracking, and disturbance rejection experiments are conducted. In order to illustrate the differences between classical HOD and DHODFC, the performance of these controllers is compared based on tracking errors and energy of control signal in the tracking experiments and fundamental dynamic characteristics in the step response experiments. DHODFC produces better tracking errors with almost same control effort in the reference tracking experiments and a faster settling time, less or no overshoot, and higher robustness in the step input experiments. Dynamic behavior of DHODFC is examined in continuous and discontinues inputs. The experimental results showed that the DHODFC is successful in the elimination of the nonminimum phase dynamics, reducing overshoots in the tracking of such discontinuous input trajectories as step and square waveforms and the rapid damping of joint vibrations.

Flexible-Joint Humanoid Balancing Augmentation via Full-State Feedback Variable Impedance Control

2021 ◽  
Vol 13 (2) ◽  
Author(s):  
Emmanouil Spyrakos-Papastavridis ◽  
Jian S. Dai
Keyword(s):  
State Feedback ◽  
Position Control ◽  
Impedance Control ◽  
Humanoid Robots ◽  
Flexible Joint ◽  
Model Free ◽  
Floating Base ◽  
Full State ◽  
Full State Feedback ◽  
Series Elastic Actuators

Abstract This paper attempts to address the quandary of flexible-joint humanoid balancing performance augmentation, via the introduction of the Full-State Feedback Variable Impedance Control (FSFVIC), and Model-Free Compliant Floating-base VIC (MCFVIC) schemes. In comparison to rigid-joint humanoid robots, efficient balancing control of compliant bipeds, powered by Series Elastic Actuators (or harmonic drives), requires the design of more sophisticated controllers encapsulating both the motor and underactuated link dynamics. It has been demonstrated that Variable Impedance Control (VIC) can improve robotic interaction performance, albeit by introducing energy-injecting elements that may jeopardize closed-loop stability. To this end, the novel FSFVIC and MCFVIC schemes are proposed, which amalgamate both collocated and non-collocated feedback gains, with power-shaping signals that are capable of preserving the system's stability/passivity during VIC. The FSFVIC and MCFVIC stably modulate the system's collocated state gains to augment balancing performance, in addition to the non-collocated state gains that dictate the position control accuracy. Utilization of arbitrarily low-impedance gains is permitted by both the FSFVIC and MCFVIC schemes propounded herein. An array of experiments involving the COmpliant huMANoid reveals that significant balancing performance amelioration is achievable through online modulation of the full-state feedback gains (VIC), as compared to utilization of invariant impedance control.

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