scholarly journals An Adaptive Hybrid Force/Motion Control Design for Robot Manipulators Interacting in Constrained Motion With Unknown Non-Rigid Environments

2012 ◽  
Author(s):  
Aghil Jafari ◽  
Mehdi Rezaei ◽  
Ali Talebi ◽  
Saeed Shiry Ghidary ◽  
Reza Monfaredi
Keyword(s):  
Motion Control ◽  
Lyapunov Method ◽  
Hybrid Control ◽  
Control Law ◽  
Environment Interaction ◽  
Task Space ◽  
Constrained Motion ◽  
End Effector ◽  
Control Approach ◽  
Rigid Environment

In the present paper, the objective of hybrid control is specified and an adaptive hybrid force/motion control approach is proposed. Based on the concept of hybrid control, the task space is decomposed into position and force controlled subspaces. An adaptive scheme is presented which makes the controller robust when the robot is in interaction with an unknown non-rigid environment. By using the classical Lyapunov method, it is demonstrated that the proposed control law ensures the tracking of the unconstrained components of the desired end-effector trajectories, with regulation of the desired contact force along the constrained direction. Simulation results verify the effectiveness of our prosperous adaptive hybrid control in robot-environment interaction.

Task-Space Control Design and Performance Evaluation for a 6DOF Stewart Nanoscale Platform

2008 ◽  
Author(s):  
Chun-Chung Li ◽  
Yung Ting ◽  
Yi-Hung Liu ◽  
Yi-Da Lee ◽  
Chun-Wei Chiu
Keyword(s):  
Feedback Control ◽  
Hybrid Control ◽  
Feedforward Control ◽  
Feedback Controller ◽  
Test Method ◽  
Computation Method ◽  
Task Space ◽  
Force Output ◽  
End Effector ◽  
Control Scheme

A 6DOF Stewart platform using piezoelectric actuators for nanoscale positioning objective is designed. A measurement method that can directly measure the pose (position and orientation) of the end-effector is developed so that task-space on-line control is practicable. The design of a sensor holder for sensor employment, a cuboid with referenced measure points, and the computation method for obtaining the end-effector parameters is introduced. A control scheme combining feedforward and feedback is proposed. The inverse model of a hysteresis model derived by using a dynamic Preisach method is used for the feedforward control. Hybrid control to maintain both the positioning and force output for nano-cutting and nano-assembly applications is designed for the feedback controller. The optimal gain of the feedback controller is searched by using relay feedback test method and genetic algorithm. In experiment, conditions with/without external load employed with feedforward, feedback, and feedforward with feedback control schemes respectively are carried out. Performance of each control scheme verifies the capability of achieving nanoscale precision. The combined feedforward and feedback control scheme is superior to the others for gaining better precision.

scholarly journals Fault-tolerant scheme for robotic manipulator—Nonlinear robust back-stepping control with friction compensation

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256491
Author(s):  
Khurram Ali ◽  
Adeel Mehmood ◽  
Jamshed Iqbal
Keyword(s):  
Hybrid Control ◽  
Autonomous Robots ◽  
Fault Tolerant ◽  
Robot Manipulator ◽  
Robotic Manipulator ◽  
Friction Model ◽  
Fault Estimation ◽  
Friction Compensation ◽  
Control Law ◽  
Control Approach

Emerging applications of autonomous robots requiring stability and reliability cannot afford component failure to achieve operational objectives. Hence, identification and countermeasure of a fault is of utmost importance in mechatronics community. This research proposes a Fault-tolerant control (FTC) for a robot manipulator, which is based on a hybrid control scheme that uses an observer as well as a hardware redundancy strategy to improve the performance and efficiency in the presence of actuator and sensor faults. Considering a five Degree of Freedom (DoF) robotic manipulator, a dynamic LuGre friction model is derived which forms the basis for design of control law. For actuator’s and sensor’s FTC, an adaptive back-stepping methodology is used for fault estimation and the nominal control law is used for the controller reconfiguration and observer is designed. Fault detection is accomplished by comparing the actual and observed states, pursued by fault tolerant method using redundant sensors. The results affirm the effectiveness of the proposed FTC strategy with model-based friction compensation. Improved tracking performance as well robustness in the presence of friction and fault demonstrate the efficiency of the proposed control approach.

scholarly journals Hybrid Control of a Pendubot System Using Nonlinear H∞ and LQR

2021 ◽  
Vol 16 ◽  
pp. 155-161
Author(s):  
Seif-El-Islam Hasseni
Keyword(s):  
Dynamic Modeling ◽  
Nonlinear Model ◽  
Equilibrium Position ◽  
Hybrid Control ◽  
Control Law ◽  
Lagrange Method ◽  
Control Approach ◽  
Linearized Model ◽  
Active Link ◽  
Pendubot System

In this paper, a hybrid control approach is synthesized for stabilizing an under-actuated mechanical system, the Pendubot. This kind of system is divided into two modes, the swing-up mode, and the balancing mode. First, dynamic modeling is established by the Euler-Lagrange method. Next, the robust nonlinear H∞ is designed for the swing-up mode, which handles with the nonlinear model. To weaken the under-actuation characteristic, the control law is developed for the active link with its coupling with the passive link. The LQR is designed for the balancing mode where LQR handles with the linearized model about the unstable top equilibrium position. A simulation is achieved under the MATLAB/Simulink environment. It shows robustness against the external inputs and the fast convergence to the equilibrium position.

scholarly journals Constant speed control of Slider-Crank mechanisms: A Joint-Task Space Hybrid Control Approach

IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Juan Alejandro Flores-Campos ◽  
Adolfo Perrusquia ◽  
Luis Hector Hernandez Gomez ◽  
Noe Gonzalez ◽  
Alejandra Armenta-Molina
Keyword(s):  
Hybrid Control ◽  
Speed Control ◽  
Constant Speed ◽  
Task Space ◽  
Control Approach ◽  
Joint Task

scholarly journals Pengendalian konvergensi eksponensial untuk omnidirectional mobile robot dengan empat roda

JURNAL ELTEK ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 108
Author(s):  
Muhammad Jodi Pamenang ◽  
Indrazno Siradjuddin ◽  
Budhy Setiawan
Keyword(s):  
Mobile Robot ◽  
Mobile Robots ◽  
Motion Control ◽  
Kinematic Model ◽  
Robot Motion ◽  
Control Law ◽  
Task Space ◽  
Wheeled Mobile Robots ◽  
Simulation Experiments ◽  
Omnidirectional Mobile Robot

Tujuan mendasar dari kontrol gerak mobile robot adalah untuk mengarahkan robot ke posisi yang diberikan secara acak pada ruang 2D. Mobile robot dengan roda omni memiliki sifat holonomic di mana memiliki keunggulan kelincahan dan permasalahan pengendalian gerak hanya pada sisi aktuator, sedangkan mobile robot dengan roda konvensional, memiliki permasalahan tambahan pengendalian gerak dalam ruang area operasional robot. Karenanya, robot omni lebih gesit untuk bergerak dalam konfigurasi ruang area kerja apa pun. Makalah ini menyajikan model kontrol konvergensi eksponensial berbasis model untuk mobile robot omnidirectional roda empat. Kontrol yang diusulkan menjamin penurunan kesalahan secara eksponensial dari gerakan robot ke setiap posisi robot yang diinginkan. Pembahasan meliputi model kinematik dan kontrol dari robot bergerak omnidirectional roda empat dan eksperimen simulasi yang telah dilakukan untuk memverifikasi kinerja kontrol yang meliputi lintasan robot 2D, serta nilai error atau kesalahan pada kontrol robot. Hasil dari eksperimen simulasi menunjukkan keefektifan kontrol yang diusulkan. Mobile robot telah bergerak ke posisi yang diinginkan pada garis lurus dengan tujuan robot yang akurat dan niali error atau kesalahan yang didapat ialah |0.02735| serta grafik error telah menurun secara eksponensial.   The fundamental objective of a mobile robot motion control is to navigate the robot to any given arbitrary posture in which robot 2D location and its heading are concerned. Mobile robots with omni wheels have a holonomic properties the advantage is of agility and motion control problems only on the actuator, while mobile robots with conventional wheels, have a problem of motion control the robot in task space. Therefore, the omni-wheeled mobile robots are more agile to move in any task space configuration.  This paper presents a model based exponential convergence control law for a four-wheeled omnidirectional mobile robot. The proposed control law guarantees an exponential error decay of mobile robot motion to any given desired robot posture. The kinematic model and the control law of a four-wheeled omnidirectional mobile robot are discussed. Simulation experiments have been conducted to verify the control law performances which include the 2D robot trajectory, the error signals, and the robot control signals. Results from simulation experiments show the effectiveness of the proposed control law. Mobile robot has moved to the desired position in a straight line with the aim of the robot that is accurate and the error or error obtained is | 0.02735 | and the error graph has decreased exponentially

scholarly journals A force/motion control approach based on trajectory planning for industrial robots with closed control architecture

IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Alejandro GutierreznGiles ◽  
Luis U. EvangelistanHernandez ◽  
Marco A. Arteaga ◽  
Carlos A. CruznVillar ◽  
Alejandro RodrigueznAngeles
Keyword(s):  
Motion Control ◽  
Trajectory Planning ◽  
Industrial Robots ◽  
Control Architecture ◽  
Control Approach

scholarly journals Adaptive Optimal Robust Control for Uncertain Nonlinear Systems Using Neural Network Approximation in Policy Iteration

2021 ◽  
Vol 11 (5) ◽  
pp. 2312
Author(s):  
Dengguo Xu ◽  
Qinglin Wang ◽  
Yuan Li
Keyword(s):  
Neural Network ◽  
Optimal Control ◽  
Robust Control ◽  
Nonlinear Systems ◽  
Policy Iteration ◽  
Control Law ◽  
Globally Asymptotically Stable ◽  
Control Approach ◽  
Input Uncertainties ◽  
Theoretical Results

In this study, based on the policy iteration (PI) in reinforcement learning (RL), an optimal adaptive control approach is established to solve robust control problems of nonlinear systems with internal and input uncertainties. First, the robust control is converted into solving an optimal control containing a nominal or auxiliary system with a predefined performance index. It is demonstrated that the optimal control law enables the considered system globally asymptotically stable for all admissible uncertainties. Second, based on the Bellman optimality principle, the online PI algorithms are proposed to calculate robust controllers for the matched and the mismatched uncertain systems. The approximate structure of the robust control law is obtained by approximating the optimal cost function with neural network in PI algorithms. Finally, in order to illustrate the availability of the proposed algorithm and theoretical results, some numerical examples are provided.

Cooperation and Null-Space Control of Networked Omni-Directional Mobile Manipulators

2020 ◽  
Author(s):  
Michael John Chua ◽  
Yen-Chen Liu
Keyword(s):  
Degrees Of Freedom ◽  
Null Space ◽  
Kinematic Model ◽  
Mobile Manipulator ◽  
Main Task ◽  
Mobile Manipulators ◽  
Robot Arm ◽  
Task Space ◽  
End Effector ◽  
Mobile Base

Abstract This paper presents cooperation and null-space control for networked mobile manipulators with high degrees of freedom (DOFs). First, kinematic model and Euler-Lagrange dynamic model of the mobile manipulator, which has an articulated robot arm mounted on a mobile base with omni-directional wheels, have been presented. Then, the dynamic decoupling has been considered so that the task-space and the null-space can be controlled separately to accomplish different missions. The motion of the end-effector is controlled in the task-space, and the force control is implemented to make sure the cooperation of the mobile manipulators, as well as the transportation tasks. Also, the null-space control for the manipulator has been combined into the decoupling control. For the mobile base, it is controlled in the null-space to track the velocity of the end-effector, avoid other agents, avoid the obstacles, and move in a defined range based on the length of the manipulator without affecting the main task. Numerical simulations have been addressed to demonstrate the proposed methods.

Design, Modelling and Simulation of a Rotational Robotic Arm

2020 ◽  
Author(s):  
Bin Wei
Keyword(s):  
Angular Velocity ◽  
3D Model ◽  
Modelling And Simulation ◽  
Robotic Arm ◽  
Forward Kinematics ◽  
Position Vector ◽  
Control Law ◽  
Model Design ◽  
End Effector ◽  
Design And Optimization

Abstract In this paper, a rotational robotic arm is designed, modelled and optimized. The 3D model design and optimization are conducted by using SolidWorks. Forward kinematics are derived so as to determine the position vector of the end effector with respect to the base, and subsequently being able to calculate the angular velocity and torque of each joint. For the goal positioning problem, the PD control law is typically used in industry. It is employed in this application by using virtual torsional springs and frictions to generate the torques and to keep the system stable.

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