Path-constrained control of a redundant manipulator in a task space

2006 ◽  
Vol 54 (3) ◽  
pp. 234-243 ◽  
Author(s):  
Mirosław Galicki
Keyword(s):  
Constrained Control ◽  
Task Space ◽  
Redundant Manipulator

Robust Control in Task Space for Redundant Manipulator

2021 ◽  
Author(s):  
Martin Crespo ◽  
Martin Mujica ◽  
Mourad Benoussaad ◽  
Sergio Junco
Keyword(s):  
Robust Control ◽  
Task Space ◽  
Redundant Manipulator

scholarly journals Robust Task Space Trajectory Tracking Control of Robotic Manipulators

2016 ◽  
Vol 21 (3) ◽  
pp. 547-568 ◽  
Author(s):  
M. Galicki
Keyword(s):  
Trajectory Tracking ◽  
Lyapunov Stability Theory ◽  
Task Space ◽  
Redundant Manipulator ◽  
Trajectory Tracking Control ◽  
Finite Time Convergence ◽  
Robot Trajectory ◽  
Vector Variable ◽  
Control Schemes ◽  
Chattering Free

Abstract This work deals with the problem of the accurate task space trajectory tracking subject to finite-time convergence. Kinematic and dynamic equations of a redundant manipulator are assumed to be uncertain. Moreover, globally unbounded disturbances are allowed to act on the manipulator when tracking the trajectory by the end-effector. Furthermore, the movement is to be accomplished in such a way as to reduce both the manipulator torques and their oscillations thus eliminating the potential robot vibrations. Based on suitably defined task space non-singular terminal sliding vector variable and the Lyapunov stability theory, we propose a class of chattering-free robust controllers, based on the estimation of transpose Jacobian, which seem to be effective in counteracting both uncertain kinematics and dynamics, unbounded disturbances and (possible) kinematic and/or algorithmic singularities met on the robot trajectory. The numerical simulations carried out for a redundant manipulator of a SCARA type consisting of the three revolute kinematic pairs and operating in a two-dimensional task space, illustrate performance of the proposed controllers as well as comparisons with other well known control schemes.

Influence of external forces on the behaviour of redundant manipulators

Robotica ◽  
1999 ◽  
Vol 17 (3) ◽  
pp. 283-292
Author(s):  
Leon Žlajpah
Keyword(s):  
Null Space ◽  
The Body ◽  
Redundant Manipulators ◽  
Redundancy Resolution ◽  
Task Space ◽  
Redundant Manipulator ◽  
Projection Technique ◽  
Position Accuracy ◽  
Two Measures ◽  
External Forces

The paper considers the influence of external forces on the behaviour of a redundant manipulator. It is assumed that the forces can act anywhere on the body of the manipulator. First, the equivalent generalized forces in the task space and the null space are defined and several special manipulator configurations regarding the equivalent forces and torques are identified. Next, two measures for the quantification of the influence of external forces on the task space are proposed. These measures are then used in the control algorithm to minimize the influence of external forces on the task space position accuracy. The control is based on the redundancy resolution at the acceleration level and the gradient projection technique. Improvement of the position accuracy is illustrated using the simulation of a four link planar manipulator.

scholarly journals Computing Robust Inverse Kinematics Under Uncertainty

2019 ◽  
Author(s):  
Anirban Sinha ◽  
Nilanjan Chakraborty
Keyword(s):  
Inverse Kinematics ◽  
Joint Space ◽  
Redundant Manipulators ◽  
Task Space ◽  
Success Rates ◽  
Redundant Manipulator ◽  
Space Error ◽  
Inverse Kinematics Problem ◽  
Robotic Tasks ◽  
Present Simulation

Abstract Robotic tasks, like reaching a pre-grasp configuration, are specified in the end effector space or task space, whereas, robot motion is controlled in joint space. Because of inherent actuation errors in joint space, robots cannot achieve desired configurations in task space exactly. Furthermore, different inverse kinematics (IK) solutions map joint space error set to task space differently. Thus for a given task with a prescribed error tolerance, all IK solutions will not be guaranteed to successfully execute the task. Any IK solution that is guaranteed to execute a task (possibly with high probability) irrespective of the realization of the joint space error is called a robust IK solution. In this paper we formulate and solve the robust inverse kinematics problem for redundant manipulators with actuation uncertainties (errors). We also present simulation and experimental results on a 7-DoF redundant manipulator for two applications, namely, a pre-grasp positioning and a pre-insertion positioning scenario. Our results show that the robust IK solutions result in higher success rates and also allows the robot to self-evaluate how successful it might be in any application scenario.

scholarly journals Kinematically Optimal Robust Control of Redundant Manipulators

2017 ◽  
Vol 22 (4) ◽  
pp. 839-865
Author(s):  
M. Galicki
Keyword(s):  
Lyapunov Stability Theory ◽  
Redundant Manipulators ◽  
Task Space ◽  
Redundant Manipulator ◽  
Finite Time Convergence ◽  
Robot Trajectory ◽  
Vector Variable ◽  
Optimal Controllers ◽  
Control Schemes ◽  
Chattering Free

Abstract This work deals with the problem of the robust optimal task space trajectory tracking subject to finite-time convergence. Kinematic and dynamic equations of a redundant manipulator are assumed to be uncertain. Moreover, globally unbounded disturbances are allowed to act on the manipulator when tracking the trajectory by the endeffector. Furthermore, the movement is to be accomplished in such a way as to minimize both the manipulator torques and their oscillations thus eliminating the potential robot vibrations. Based on suitably defined task space non-singular terminal sliding vector variable and the Lyapunov stability theory, we derive a class of chattering-free robust kinematically optimal controllers, based on the estimation of transpose Jacobian, which seem to be effective in counteracting both uncertain kinematics and dynamics, unbounded disturbances and (possible) kinematic and/or algorithmic singularities met on the robot trajectory. The numerical simulations carried out for a redundant manipulator of a SCARA type consisting of the three revolute kinematic pairs and operating in a two-dimensional task space, illustrate performance of the proposed controllers as well as comparisons with other well known control schemes.

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