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.

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

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 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.

Computed Torque Control Method for Under-Actuated Manipulator

2009 ◽  
Author(s):  
Ambrus Zelei ◽  
La´szlo´ L. Kova´cs ◽  
Ga´bor Ste´pa´n
Keyword(s):  
Control Method ◽  
Differential Algebraic Equations ◽  
Torque Control ◽  
Pd Controller ◽  
Algebraic Equations ◽  
Ducted Fan ◽  
Computed Torque Control ◽  
Simulation Results ◽  
Load Angle ◽  
Computed Torque

The paper presents the dynamic analysis of a crane-like manipulator system equipped with complementary cables and ducted fan actuators. The investigated under-actuated mechanical system is described by a system of differential-algebraic equations. The position/orientation control problem is investigated with respect to the trajectory generation and the fine positioning of the payload. The closed form results include the desired actuator forces as well as the nominal load angle corresponding to the desired motion of the payload. Considering a PD controller, numerical simulation results and also experiments demonstrate the applicability of the concept of using complementary actuators for controlling the swinging motion of the payload.

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>

scholarly journals Artillery-Missile System Control Under Disturbances Conditions Using a Modified Computed Torque Control Method

2019 ◽  
Vol 10 (1) ◽  
pp. 75-90
Author(s):  
Piotr SZMIDT
Keyword(s):  
Control Method ◽  
Angular Position ◽  
Torque Control ◽  
System Model ◽  
Graphical Form ◽  
System Control ◽  
Control Parameters ◽  
Computed Torque Control ◽  
Missile System ◽  
Computed Torque

The paper addresses the issue of remote control of a artillery-missile system when the system is affected by dynamic and kinematic disturbances. The dynamic disturbances analysed in the paper includes disturbances from shots fired while kinematic disturbances are excitation related to the motion of the base on which the system is installed. The object of the study is a system model based on the ZU-23-2MR artillery-missile system produced and operated in Poland, designed to combat lightly armoured air, naval and ground targets. Once the system model and the assumed disturbance types are discussed, further in the paper the system control in azimuth and elevation angular position is analysed. Computed torque control with additional corrective components is presented. A certain inertia in system drive models is also adopted. Additionally, uncertainty of model identification is assumed, i.e. object control parameters are different from the parameters of the model which serves as basis for calculating the control parameters. Differences in weights, mass moments of inertia and friction torques arising in the system's drive elements are taken into account. The last part of the paper includes an analysis of the speed of target interception and precision of tracking a manoeuvring aerial target with the interference affecting the system. It was assumed that the system is located on a ship, therefore kinematic disturbances are related to the ship's movement on the sea waves, as well as dynamic disturbances are related to firing the weapon. All simulations were performed in the Scilab environment for a non-linear model of the system. Essential results are shown in a graphical form.

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