Optimal adaptive computed torque control for haptic-teleoperation system with uncertain dynamics

Author(s):  
Tayfun Abut ◽  
Servet Soyguder

This study aimed to eliminate dynamic uncertainty, one of the main problems of haptic teleoperation robotic systems. The optimal adaptive computed torque control method was used to overcome this problem. As is known, excellent stability and transparency are required in teleoperation systems. However, dynamic uncertainty that causes stability problems in the control of these systems also causes poor performance. In conventional adaptive computed torque control methods, updating the parameters of the system is generally discussed, but updating the control coefficients of vital importance in the control of the system is not considered. In the proposed method, an adaptation rule has been created to update uncertain parameters. In addition, the gray wolf optimization algorithm, one of the current optimization algorithms, has been proposed and applied to obtain the control coefficients of the system. The position tracking stability of the system was examined by using Lyapunov stability analysis method. As a result, both simulation and real-time optimal adaptive computational torque control method were used and bilateral position and force control was performed and the performance results of the system are obtained graphically and examined. Optimal adaptive computed torque control method obtained using the gray wolf optimization algorithm was used first in the literature search and success results have been obtained. In this regard, the authors have the idea that this work is an innovative aspect of both simulation and real time with the optimal adaptive computed torque control method.

Robotica ◽  
2021 ◽  
pp. 1-13
Author(s):  
Xiaogang Song ◽  
Yongjie Zhao ◽  
Chengwei Chen ◽  
Liang’an Zhang ◽  
Xinjian Lu

SUMMARY In this paper, an online self-gain tuning method of a PD computed torque control (CTC) is used for a 3UPS-PS parallel robot. The CTC is applied to the 3UPS-PS parallel robot based on the robot dynamic model which is established via a virtual work principle. The control system of the robot comprises a nonlinear feed-forward loop and a PD control feedback loop. To implement real-time online self-gain tuning, an adjustment method based on the genetic algorithm (GA) is proposed. Compared with the traditional CTC, the simulation results indicate that the control algorithm proposed in this study can not only enhance the anti-interference ability of the system but also improve the trajectory tracking speed and the accuracy of the 3UPS-PS parallel robot.


2021 ◽  
pp. 1-9
Author(s):  
G. Perumalsamy ◽  
Deepak Kumar ◽  
Joel Jose ◽  
S. Joseph Winston ◽  
S. Murugan

2011 ◽  
Vol 225-226 ◽  
pp. 978-981
Author(s):  
Bing Shao ◽  
En Tao Yuan ◽  
Zhong Hai Yu

Lie groups and Lie algebras are used to research the dynamics and computed torque law control of free flying space robot systems. First the adjoint transformations and adjoint operators of Lie groups and Lie algebras are discussed. Then the free flying base systems are transformed to fixed base systems. The inverse dynamics and forward dynamics are described with Lie groups and Lie algebras. The computed torque control law is used to simulate with the results of dynamics. The simulation results show that with the method the dynamical simulation problems of space robot can be solved quickly and efficiently. This built the foundation of real-time control based on dynamics. The computed torque control law has good performance.


Author(s):  
La´szlo´ L. Kova´cs ◽  
Jo´zsef Ko¨vecses ◽  
Ambrus Zelei ◽  
La´szlo´ Bencsik ◽  
Ga´bor Ste´pan

This paper aims to generalize the computed torque control method for underactuated systems which are modeled by a non-minimum set of generalized coordinates subjected to geometric constraints. The control task of the underactuated robot is defined in the form of servo constraint equations that have the same number as the number of independent control inputs. A PD controller is synthesized based on projecting the equations of motion into the nullspace of the distribution matrix of the actuator forces/torques. The results are demonstrated by numerical simulation and experiments conducted on a two degrees-of-freedom device.


2021 ◽  
Vol 17 (3) ◽  
pp. 22-28
Author(s):  
Maryam Sadeq Ahmed ◽  
Ali Hussien M Mary ◽  
Hisham Hassan Jasim

This paper presents a robust control method for the trajectory control of the robotic manipulator. The standard Computed Torque Control (CTC) is an important method in the robotic control systems but its not robust to system uncertainty and external disturbance. The proposed method overcome the system uncertainty and external disturbance problems. In this paper, a robustification term has been added to the standard CTC. The stability of the proposed control method is approved by the Lyapunov stability theorem.  The performance of the presented controller is tested by MATLAB-Simulink environment and is compared with different control methods to illustrate its robustness and performance.


2020 ◽  
Vol 18 (2) ◽  
pp. 269
Author(s):  
Jelena Vidaković ◽  
Vladimir Kvrgić ◽  
Mihailo Lazarević ◽  
Pavle Stepanić

A development of a robot control system is a highly complex task due to nonlinear dynamic coupling between the robot links. Advanced robot control strategies often entail difficulties in implementation, and prospective benefits of their application need to be analyzed using simulation techniques. Computed torque control (CTC) is a feedforward control method used for tracking of robot’s time-varying trajectories in the presence of varying loads. For the implementation of CTC, the inverse dynamics model of the robot manipulator has to be developed. In this paper, the addition of CTC compensator to the feedback controller is considered for a Spatial disorientation trainer (SDT). This pilot training system is modeled as a 4DoF robot manipulator with revolute joints. For the designed mechanical structure, chosen actuators and considered motion of the SDT, CTC-based control system performance is compared with the traditional speed PI controller using the realistic simulation model. The simulation results, which showed significant improvement in the trajectory tracking for the designed SDT, can be used for the control system design purpose as well as within mechanical design verification.


2018 ◽  
Vol 15 (5) ◽  
pp. 172988141880173 ◽  
Author(s):  
Chao Chen ◽  
Chengrui Zhang ◽  
Tianliang Hu ◽  
Hepeng Ni ◽  
WeiChao Luo

Computed torque control is an effective control scheme for trajectory tracking of robotic manipulators. However, computed torque control requires precise dynamic models of robotic manipulators and is severely affected by uncertain dynamics. Thus, a new scheme that combines a computed torque control and a novel model-assisted extended state observer is developed for the robust tracking control of robotic manipulators subject to structured and unstructured uncertainties to overcome the disadvantages of computed torque control and exploit its merits. The model-assisted extended state observer is designed to estimate and compensate these uncertain dynamics as a lumped disturbance online, which further improves the disturbance rejection property of a robotic system. Global uniform ultimate boundedness stability with an exponential convergence of a closed-loop system is verified through Lyapunov method. Simulations are performed on a two degree-of-freedom manipulator to verify the effectiveness and superiority of the proposed controller.


Author(s):  
Y. Meddahi ◽  
K. Zemalache Meguenni

For the trajectory following problem of an airship, the standard computed torque control law is shown to be robust with respect to unknown dynamics by judiciously choosing the feedback gains and the estimates of the nonlinear dynamics. In the first part of this paper, kinematics and dynamics modeling of the airships is presented. Euler angles and parameters are used in the formulation of this model and the technique of Computed Torque control is introduced. In the second part of the paper, we develop a methodology of control that allows the airship to accomplish a prospecting mission of an environment, as the follow-up of a trajectory by the simulation who results show that Computed Torque control method is suitable for airships.


Sign in / Sign up

Export Citation Format

Share Document