A Redundant Manipulator Joint Torque Estimation Method Based on Disturbance Observer

2020 ◽  
Vol 29 (07n08) ◽  
pp. 2040015
Author(s):  
Xun Liu ◽  
Yaqiu Liu ◽  
Hanchen Zhao

With the continuous development of the robot industry, both industrial robots and collaborative robots are developing towards light type and intelligence. The core issue is that how to improve the dynamic control performance of robots and reduce costs. The accurate torque feedback control can be achieved by introducing a joint torque sensor. The disadvantages brought by it are higher cost and the limited performance of the torque sensor. Therefore, on the basis of the traditional current estimated torque, combined with the accurate joint torque data fed back by the torque sensor, a method to estimate the harmonic transmission torque in the joint based on the disturbance observer is proposed, and a joint torque model is constructed. At the same time, the compensation factor is introduced to improve the accuracy of torque estimation. In the method proposed in this paper, the theoretical position and actual position, speed difference and motor current of the dual encoder on the motor side and the link side are used to estimate the harmonic transmission torque through the disturbance observer, and the corresponding coefficient is identified. By calibrating the transmission error compensation term and friction force with the torque sensor, the joint torque estimation model is obtained, and the sensorless joint torque estimation can be realized. This method does not require additional torque error compensation caused by harmonic drive deformation in the controller. Therefore, the torque control method without torque sensor is adopted in batch, which is not affected by the configuration and dynamic parameters of the manipulator. In the experiment, the output data of the joint torque sensor is used for testing and comparison. Through the single joint and redundant robot manipulator integration testing, the effectiveness of the proposed joint torque estimation method is verified.

Author(s):  
Hwadong Sun ◽  
Seunghwan Kim ◽  
Daehie Hong ◽  
Daeho Kim ◽  
Jung-Hoon Hwang ◽  
...  

1991 ◽  
Vol 27 (6) ◽  
pp. 693-699
Author(s):  
Junichi IMURA ◽  
Toshiharu SUGIE ◽  
Yasuyoshi YOKOKOHJI ◽  
Tsuneo YOSHIKAWA

Measurement ◽  
2020 ◽  
Vol 152 ◽  
pp. 107328
Author(s):  
Kang Han ◽  
Liheng Chen ◽  
Mingyi Xia ◽  
Qinwen Wu ◽  
Zhenbang Xu ◽  
...  

Mechatronics ◽  
2019 ◽  
Vol 63 ◽  
pp. 102265 ◽  
Author(s):  
Jae-Kyung Min ◽  
Kuk-Hyun Ahn ◽  
Hui-Chang Park ◽  
Jae-Bok Song

Author(s):  
Yoon Haeng Lee ◽  
Young Hun Lee ◽  
Hyunyong Lee ◽  
Hansol Kang ◽  
Luong Tin Phan ◽  
...  

Author(s):  
Anwar Alkeilani ◽  
Le Yi Wang ◽  
Hao Ying

At the present time, both control and estimation accuracies of engine torque are causes for under-achieving optimal drivability and performance in today’s production vehicles. The major focus in this area has been to enhance torque estimation and control accuracies using existing open-loop torque control and estimation structures. Such an approach does not guarantee optimum torque tracking accuracy and optimum estimation accuracy due to air flow and efficiencies estimations errors. Furthermore, current approach overlooks the fast torque path tracking which does not have any related feedback. Recently, explicit torque feedback control has been proposed in the literature using either estimated or measured torques as feedback to control the torque using the slow torque path only. We propose the usage of a surface acoustic wave (SAW) torque sensor to measure the engine brake torque and feedback the signal to control the torque using both the fast and slow torque paths utilizing an inner-outer loop control structure. The fast torque path feedback is coordinated with the slow torque path by a novel method using the potential torque that is adapted to the sensor reading. The torque sensor signal enables a fast and explicit torque feedback control that can correct torque estimation errors and improve drivability, emission control, and fuel economy. Control-oriented engine models for the 3.6L engine are developed. Computer simulations are performed to investigate the advantages and limitations of the proposed control strategy, versus the existing strategies. The findings include an improvement of 14% in gain margin and 60% in phase margin when the torque feedback is applied to the cruise control torque request at the simulated operating point. This study demonstrates that the direct torque feedback is a powerful technology with promising results for improved powertrain performance and fuel economy.


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