High-accuracy trajectory tracking of industrial robot manipulator using adaptive-learning scheme

1999 ◽  
Vol 121 (2) ◽  
pp. 285-292 ◽  
Author(s):  
Dong Sun ◽  
James K. Mills

More and more industrial robot operations demand high-accuracy trajectory performance which may not be achievable by using conventional PID control. This paper describes a new adaptive control method with a learning ability in the repetitive tasks, called the Adaptive-Learning (A-L) scheme. The method is based on the proposed theory of two operational modes: the single operational mode and the repetitive operational mode. In the single operational mode, the control is an adaptive control with a new parameter adaptation law using information from the previous trials. In the repetitive operational mode, the control is a model-based iterative learning control. The advantage of the A-L scheme lies in the ability to guarantee convergence in both modes. Theoretical analysis and experimental evaluation on a commercial robot demonstrate the effectiveness of the A-L scheme in controlling an industrial robot manipulator.


Author(s):  
Suhua Li ◽  
Jiacheng Xie ◽  
Fang Ren ◽  
Xin Zhang ◽  
Xuewen Wang ◽  
...  

AbstractThe movement of the floating connecting mechanism between a hydraulic support and scraper conveyor is space movement; thus, when the hydraulic support pushes the scraper conveyor, there is an error between the actual distance of the scraper conveyor and the theoretical moving distance. As a result, the scraper conveyor cannot obtain the straightness requirement. Therefore, the movement law of the floating connecting mechanism between the hydraulic support and scraper conveyor is analyzed and programmed into the Unity3D to realize accurate pushing of the scraper conveyor via hydraulic support. The Coal Seam + Equipment Joint Virtual Straightening System is established, and a straightening method based on the motion law of a floating connection is proposed as the default method of the system. In addition, a straightening simulation of the scraper conveyor was performed on a complex coal seam floor, the results demonstrate that the average straightening error of the scraper conveyor is within 2–8 mm, and is in direct proportion to the fluctuation of the coal seam floor in the strike of the seam with high accuracy, the straightness of scraper conveyor is more affected by the subsidence terrain during straightening than by the bulge terrain. And some conclusions are verified by experiment. Based on the verification of the relevant conclusions, a comparison and analysis of Longwall Automation Steering Committee (LASC) straightening technology and default straightening method in the simulation system shows that the straightness accuracy of LASC straightening technology under complex floor conditions is slightly less than that of the default straightening method in the proposed system.


2021 ◽  
Vol 11 (13) ◽  
pp. 5914
Author(s):  
Daniel Reyes-Uquillas ◽  
Tesheng Hsiao

In this article, we aim to achieve manual guidance of a robot manipulator to perform tasks that require strict path following and would benefit from collaboration with a human to guide the motion. The robot can be used as a tool to increase the accuracy of a human operator while remaining compliant with the human instructions. We propose a dual-loop control structure where the outer admittance control loop allows the robot to be compliant along a path considering the projection of the external force to the tangential-normal-binormal (TNB) frame associated with the path. The inner motion control loop is designed based on a modified sliding mode control (SMC) law. We evaluate the system behavior to forces applied from different directions to the end-effector of a 6-DOF industrial robot in a linear motion test. Next, a second test using a 3D path as a tracking task is conducted, where we specify three interaction types: free motion (FM), force-applied motion (FAM), and combined motion with virtual forces (CVF). Results show that the difference of root mean square error (RMSE) among the cases is less than 0.1 mm, which proves the feasibility of applying this method for various path-tracking applications in compliant human–robot collaboration.


2013 ◽  
Vol 694-697 ◽  
pp. 1652-1655
Author(s):  
Ji Yan Wang

PD control method is widely utilized for the dynamic characteristics controlling in industrial robot manipulator area. The disturbance is usually uncertain in reality; the traditional PD controller is limited in that case. In this paper, a PD robust controller is introduced to optimize the convergence and stability of PD controller and avoid the extreme initial driving torque for two-link manipulator system. Using the co-simulation on Matlab/ Simulink and ADAMS, the paper designs a PD robust controller under uncertain upper bound disturbance and completes track control and driving torque simulation trial. The superiority of the two-link manipulators PD robust controller is verified through result comparison and analysis.


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