Predictive Trajectory Tracking Algorithm of Underactuated Systems Based On the Calculus of Variations

2021 ◽  
Author(s):  
Bálint Bodor ◽  
Ambrus Zelei ◽  
László Bencsik
Keyword(s):  
Inverse Dynamics ◽  
Numerical Study ◽  
Tracking Error ◽  
Torque Control ◽  
Underactuated Systems ◽  
Inverse Kinematics Problem ◽  
Predictive Controller ◽  
Servo Constraints ◽  
The Stability ◽  
Computed Torque

Abstract The tracking control of underactuated systems is a challenging problem due to the structural differences compared to fully actuated systems. Contrarily to fully actuated systems, resolving the inverse kinematics problem of underactuated systems is not possible independently from the dynamic equations. Instead, the inverse dynamics must be addressed. It is common to extend the computed torque control (CTC) technique with servo constraints. Besides the CTC's clearness, the stability of the system cannot be always guaranteed. A novel predictive controller (PC) is presented in this paper. Our PC applies the variational principle to design the motion of the system in order to achieve a stable motion with the lowest possible tracking error. To demonstrate the applicability and the performance of the PC method, a numerical study is presented for a planar manipulator resulting in about 20% RMS error compared to the CTC method from the literature.

Robust Computed Torque Schemes for Mechanical Manipulators: Nonadaptive Versus Adaptive

1991 ◽  
Vol 113 (2) ◽  
pp. 324-327 ◽  
Author(s):  
Y. H. Chen
Keyword(s):  
Finite Time ◽  
Tracking Control ◽  
Tracking Error ◽  
Statistical Information ◽  
Torque Control ◽  
Control Algorithms ◽  
Computed Torque Control ◽  
Control Schemes ◽  
Mechanical Manipulators ◽  
Computed Torque

We consider the tracking control problem of mechanical manipulators in the presence of uncertainty. Two classes of control algorithms are proposed. If the possible bound of the uncertainty is known, a class of nonadaptive robust computed torque control schemes is used. The control guarantees the tracking error to be confined within a specified region after a finite time. If the bound of uncertainty is unknown, a class of adaptive robust computed torque control schemes is used. The control guarantees the tracking error to converge to zero. Both classes of controls are continuous. No statistical information on the uncertainty is ever assumed.

Research on Grinding Robot for Trajectory Control Based on Computed Torque

2011 ◽  
Vol 58-60 ◽  
pp. 2392-2395
Author(s):  
Tong Ying Guo ◽  
Jie Jia Li ◽  
Hai Chen Wang
Keyword(s):  
Tracking Error ◽  
Response Speed ◽  
Trajectory Control ◽  
Torque Control ◽  
Position Tracking ◽  
Quick Response ◽  
Experimental Platform ◽  
Computed Torque Control ◽  
Velocity Tracking ◽  
Computed Torque

In this paper, in order to achieve high-precision trajectory control of grinding robot, the method of computed torque control is proposed based on PD feedback, a single-joint robot experimental platform was built, position and velocity tracking experiment is carried out with empty Load and load. Experimental results show that the method of computed torque based on PD feedback control has the characteristic of quick response speed and small position tracking error.

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.

Development of a model reference computed torque controller for a human lower extremity exoskeleton robot

2021 ◽  
pp. 095965182110090
Author(s):  
SK Hasan ◽  
Anoop K Dhingra
Keyword(s):  
Control System ◽  
Physical Therapy ◽  
Lower Extremity ◽  
Torque Control ◽  
Joint Torque ◽  
Tracking Performance ◽  
Model Reference ◽  
Exoskeleton Robot ◽  
The Stability ◽  
Computed Torque

Exoskeleton robot–based neurorehabilitation has received a lot of attention recently due to positive evidence supporting its ability to provide different forms of physical therapy and in helping evaluate the patient recovery rate accurately. The performance of exoskeleton robot–based physical therapy depends on the accuracy of the motion control system. While the computed torque control scheme based on inverse dynamics is ideal from a theoretical perspective, the stability and tracking performance strongly depends on the model accuracy. Expecting a deterministic payload for a rehabilitation robot is impractical, which makes the computed torque controller unrealistic for such an application. In this article, a 7-degree-of-freedom human lower extremity dynamic model is developed using the Lagrange method and a novel Model Reference Computed Torque Controller is utilized for control. The computed torque controller is used to estimate the joint torque requirements for tracking a trajectory. Calculated joint torques are applied to a similarly structured plant with different parameters. The deviation of the plant from the model is calculated. A proportional–integral–derivative controller is employed to force the plant to behave like the robot model. A realistic friction model is incorporated to simulate joint friction in the plant. The stability and tracking performance of the control system is presented for sequential as well as simultaneous joint movements. To verify the robustness of the developed controller, analysis of variance statistical technique is used.

scholarly journals A Novel Dual Quaternion Based Cost Effcient Recursive Newton-Euler Inverse Dynamics Algorithm

2019 ◽  
Vol 1 (2) ◽  
pp. 144-168
Author(s):  
Cristiana Miranda de Farias
Keyword(s):  
Feedback Linearization ◽  
Inverse Dynamics ◽  
Joint Space ◽  
Linearization Method ◽  
Torque Control ◽  
Dual Quaternion ◽  
Serial Manipulators ◽  
Dual Quaternions ◽  
Forward Kinematic ◽  
Computed Torque

In this paper, the well known recursive Newton-Euler inverse dynamics algorithm for serial manipulators is reformulated into the context of the algebra of Dual Quaternions. Here we structure the forward kinematic description with screws and line displacements rather than the well established Denavit-Hartemberg parameters, thus accounting better efficiency, compactness and simpler dynamical models. We also present here the closed solution for the dqRNEA, and to do so we formalize some of the algebra for dual quaternion-vectors and dual quaternion-matrices. With a closed formulation of the dqRNEA we also create a dual quaternion based formulation for the computed torque control, a feedback linearization method for controlling a serial manipulator's torques in the joint space. Finally, a cost analysis of the main Dual Quaternions operations and of the Newton-Euler inverse dynamics algorithm as a whole is made and compared with other results in the literature.

Sign in / Sign up

Export Citation Format

Share Document