Servo-Constraint Based Computed Torque Control of Underactuated Mechanical Systems

2011 ◽  
Author(s):  
La´szlo´ L. Kova´cs ◽  
Jo´zsef Ko¨vecses ◽  
Ambrus Zelei ◽  
La´szlo´ Bencsik ◽  
Ga´bor Ste´pan
Keyword(s):  
Degrees Of Freedom ◽  
Control Method ◽  
Equations Of Motion ◽  
Geometric Constraints ◽  
Torque Control ◽  
Underactuated Mechanical Systems ◽  
Computed Torque Control ◽  
Distribution Matrix ◽  
Underactuated Robot ◽  
Computed Torque

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.

scholarly journals Dynamic Analysis Of Two Link Robot Manipulator For Control Design Using PID Computed Torque Control.

2016 ◽  
Vol 5 (4) ◽  
pp. 277
Author(s):  
Jolly Atit Shah ◽  
S S Rattan
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Robot Manipulator ◽  
Equation Of Motion ◽  
Torque Control ◽  
Computed Torque Control ◽  
Speed Accuracy ◽  
Accuracy And Repeatability ◽  
Computed Torque

<p>Due to their advantage of high speed, accuracy and repeatability, robot manipulators have become major component of manufacturing industries and even now a days they become part of routine life.            </p><p>Two link robot manipulator is a very basic classical and simple example of robot followed in understanding of basic fundamentals of robotic manipulator. The equation of motion for two link robot is a nonlinear differential equation. For higher degrees of freedom, as the closed form solutions are very difficult we have to use numerical solution. Here we focused mainly on control of robot manipulator to get the desired position using combination of two classical methods PID and computed torque control method after deriving the equation of motion. For the same simulation is represented using MATLAB and compared with computed torque control method.</p>

A PD Computed Torque Control Method with Online Self-gain Tuning for a 3UPS-PS Parallel Robot

Robotica ◽  
2021 ◽  
pp. 1-13
Author(s):  
Xiaogang Song ◽  
Yongjie Zhao ◽  
Chengwei Chen ◽  
Liang’an Zhang ◽  
Xinjian Lu
Keyword(s):  
Feedback Loop ◽  
Control Method ◽  
Virtual Work ◽  
Parallel Robot ◽  
Torque Control ◽  
Virtual Work Principle ◽  
Tuning Method ◽  
Computed Torque Control ◽  
Control Feedback ◽  
Computed Torque

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.

Computed Torque Control Method for Two-Axis Planar Serial Robotic Arm

2021 ◽  
pp. 1-9
Author(s):  
G. Perumalsamy ◽  
Deepak Kumar ◽  
Joel Jose ◽  
S. Joseph Winston ◽  
S. Murugan
Keyword(s):  
Control Method ◽  
Torque Control ◽  
Robotic Arm ◽  
Computed Torque Control ◽  
Computed Torque

Adaptive Computed Reference Computed Torque Control of Flexible Robots

1995 ◽  
Vol 117 (1) ◽  
pp. 31-36 ◽  
Author(s):  
I. M. M. Lammerts ◽  
F. E. Veldpaus ◽  
M. J. G. Van de Molengraft ◽  
J. J. Kok
Keyword(s):  
Degrees Of Freedom ◽  
Torque Control ◽  
Control Technique ◽  
Control Law ◽  
State Variables ◽  
Flexible Robots ◽  
Computed Torque Control ◽  
Link Flexibility ◽  
Simulation Results ◽  
Computed Torque

This paper presents a motion control technique for flexible robots and manipulators. It takes into account both joint and link flexibility and can be applied in adaptive form if robot parameters are unknown. It solves the main problems that are related to the fact that the number of degrees of freedom exceeds both the number of actuators and the number of output variables. The proposed method results in trajectory tracking while all state variables remain bounded. Global, asymptotic stability is ensured for all values of the stiffnesses of joints and links. To show the characteristics of the proposed control law, some simulation results are presented.

scholarly journals Control par calculado para seguimiento de trayectoria aplicado a la dinámica de un robot de 3gdl con propósitos didácticos

2020 ◽  
pp. 1-8
Author(s):  
Juan Carlos Hernández-Durón ◽  
José Luis Ortiz-Simón ◽  
Martha Aguilera-Hernandez ◽  
Daniel Olivares-Caballero
Keyword(s):  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Torque Control ◽  
Work Place ◽  
A Value ◽  
Computed Torque Control ◽  
Christoffel Symbols ◽  
Gravitational Vector ◽  
Three Degrees Of Freedom ◽  
Computed Torque

The article shows the needed procedure to obtain the dynamic model of a robot, with the purpose of being able to follow a planned path using the control law “CTC” Computed Torque Control. The robot was designed in a simple way for didactic reasons, this robot has three degrees of freedom, four links and three joints to move around in the work place. Two out of these joints are rotatory joints meanwhile the third one is a prismatic joint. The dynamic model of the robot is obtained using the Jacobians and Christoffel symbols of the center of mas of each link. Also including the Gravitational vector and the frictions of each joint. The objective of the dynamic model is to be able to simulate the robot in “Simulink” and test different paths using the computed torque control in which the gains of the control will be manipulated until a value that satisfies the desired path is found

scholarly journals Robust Computed Torque Control for Uncertain Robotic Manipulatorss

2021 ◽  
Vol 17 (3) ◽  
pp. 22-28
Author(s):  
Maryam Sadeq Ahmed ◽  
Ali Hussien M Mary ◽  
Hisham Hassan Jasim
Keyword(s):  
Control Systems ◽  
Control Method ◽  
External Disturbance ◽  
Torque Control ◽  
Robotic Control ◽  
System Uncertainty ◽  
Computed Torque Control ◽  
And Performance ◽  
The Stability ◽  
Computed Torque

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.

scholarly journals COMPUTED TORQUE CONTROL FOR A SPATIAL DISORIENTATION TRAINER

2020 ◽  
Vol 18 (2) ◽  
pp. 269
Author(s):  
Jelena Vidaković ◽  
Vladimir Kvrgić ◽  
Mihailo Lazarević ◽  
Pavle Stepanić
Keyword(s):  
Control System ◽  
Robot Control ◽  
Inverse Dynamics ◽  
Control Method ◽  
Robot Manipulator ◽  
Training System ◽  
Torque Control ◽  
Spatial Disorientation ◽  
Computed Torque Control ◽  
Computed Torque

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.

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

2021 ◽  
pp. 095965182110480
Author(s):  
Tayfun Abut ◽  
Servet Soyguder
Keyword(s):  
Real Time ◽  
Optimization Algorithm ◽  
Control Method ◽  
Torque Control ◽  
Gray Wolf ◽  
Uncertain Dynamics ◽  
Computed Torque Control ◽  
Dynamic Uncertainty ◽  
Control Coefficients ◽  
Computed Torque

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.

scholarly journals PD-computed torque control for an autonomous airship

2019 ◽  
Vol 8 (1) ◽  
pp. 44
Author(s):  
Y. Meddahi ◽  
K. Zemalache Meguenni
Keyword(s):  
Control Method ◽  
Torque Control ◽  
Kinematics And Dynamics ◽  
Control Law ◽  
Euler Angles ◽  
Dynamics Modeling ◽  
Computed Torque Control ◽  
Trajectory Following ◽  
Computed Torque

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.

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