Tracking Control of Redundant Manipulators with Singularity-Free Orientation Representation and Null-Space Compliant Behaviour

2018 ◽  
pp. 15-28 ◽  
Author(s):  
Fabio Vigoriti ◽  
Fabio Ruggiero ◽  
Vincenzo Lippiello ◽  
Luigi Villani
Keyword(s):  
Tracking Control ◽  
Null Space ◽  
Redundant Manipulators

Gradient Optimization of Inverse Dynamics for Robotic Manipulator Motion Planning Using Combined Optimal Control

2017 ◽  
Author(s):  
Shangdong Gong ◽  
Redwan Alqasemi ◽  
Rajiv Dubey
Keyword(s):  
Optimal Control ◽  
Motion Planning ◽  
Inverse Dynamics ◽  
Null Space ◽  
Optimal Solution ◽  
Human Motion ◽  
Optimization Techniques ◽  
Redundant Manipulators ◽  
Robot Arm ◽  
Gradient Optimization

Motion planning of redundant manipulators is an active and widely studied area of research. The inverse kinematics problem can be solved using various optimization methods within the null space to avoid joint limits, obstacle constraints, as well as minimize the velocity or maximize the manipulability measure. However, the relation between the torques of the joints and their respective positions can complicate inverse dynamics of redundant systems. It also makes it challenging to optimize cost functions, such as total torque or kinematic energy. In addition, the functional gradient optimization techniques do not achieve an optimal solution for the goal configuration. We present a study on motion planning using optimal control as a pre-process to find optimal pose at the goal position based on the external forces and gravity compensation, and generate a trajectory with optimized torques using the gradient information of the torque function. As a result, we reach an optimal trajectory that can minimize the torque and takes dynamics into consideration. We demonstrate the motion planning for a planar 3-DOF redundant robotic arm and show the results of the optimized trajectory motion. In the simulation, the torque generated by an external force on the end-effector as well as by the motion of every link is made into an integral over the squared torque norm. This technique is expected to take the torque of every joint into consideration and generate better motion that maintains the torques or kinematic energy of the arm in the safe zone. In future work, the trajectories of the redundant manipulators will be optimized to generate more natural motion as in humanoid arm motion. Similar to the human motion strategy, the robot arm is expected to be able to lift weights held by hands, the configuration of the arm is changed along from the initial configuration to a goal configuration. Furthermore, along with weighted least norm (WLN) solutions, the optimization framework will be more adaptive to the dynamic environment. In this paper, we present the development of our methodology, a simulated test and discussion of the results.

scholarly journals A Synthetic Algorithm for Tracking a Moving Object in a Multiple-Dynamic Obstacles Environment Based on Kinematically Planar Redundant Manipulators

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Hongzhe Jin ◽  
Hui Zhang ◽  
Zhangxing Liu ◽  
Decai Yang ◽  
Dongyang Bie ◽  
...  
Keyword(s):  
Real Time ◽  
Null Space ◽  
Inverse Kinematic ◽  
Moving Object ◽  
Redundant Manipulators ◽  
Joint Angles ◽  
The Real ◽  
Time Path ◽  
Planar Manipulators ◽  
Spline Filter

This paper presents a synthetic algorithm for tracking a moving object in a multiple-dynamic obstacles environment based on kinematically planar manipulators. By observing the motions of the object and obstacles, Spline filter associated with polynomial fitting is utilized to predict their moving paths for a period of time in the future. Several feasible paths for the manipulator in Cartesian space can be planned according to the predicted moving paths and the defined feasibility criterion. The shortest one among these feasible paths is selected as the optimized path. Then the real-time path along the optimized path is planned for the manipulator to track the moving object in real-time. To improve the convergence rate of tracking, a virtual controller based on PD controller is designed to adaptively adjust the real-time path. In the process of tracking, the null space of inverse kinematic and the local rotation coordinate method (LRCM) are utilized for the arms and the end-effector to avoid obstacles, respectively. Finally, the moving object in a multiple-dynamic obstacles environment is thus tracked via real-time updating the joint angles of manipulator according to the iterative method. Simulation results show that the proposed algorithm is feasible to track a moving object in a multiple-dynamic obstacles environment.

Hierarchical tracking task control in redundant manipulators with compliance control in the null-space

Mechatronics ◽  
2018 ◽  
Vol 55 ◽  
pp. 171-179 ◽  
Author(s):  
Abbas Karami ◽  
Hamid Sadeghian ◽  
Mehid Keshmiri ◽  
Giuseppe Oriolo
Keyword(s):  
Null Space ◽  
Tracking Task ◽  
Redundant Manipulators ◽  
Compliance Control ◽  
Task Control

Force, orientation and position control in redundant manipulators in prioritized scheme with null space compliance

2019 ◽  
Vol 85 ◽  
pp. 23-33 ◽  
Author(s):  
Abbas Karami ◽  
Hamid Sadeghian ◽  
Mehid Keshmiri ◽  
Giuseppe Oriolo
Keyword(s):  
Position Control ◽  
Null Space ◽  
Redundant Manipulators

A Null-Space Solution of the Inverse Kinematics of Redundant Manipulators Based on a Decomposition of Screws

1993 ◽  
Vol 115 (3) ◽  
pp. 530-539 ◽  
Author(s):  
R. P. Podhorodeski ◽  
A. A. Goldenberg ◽  
R. G. Fenton
Keyword(s):  
Inverse Kinematics ◽  
Null Space ◽  
Analytical Application ◽  
Redundant Manipulators ◽  
Numerical Application ◽  
Open Chain ◽  
Computational Costs ◽  
Space Solution ◽  
Joint Velocity

In this paper, an approach for solving the inverse kinematics (velocity) problem for redundant open-chain manipulators is addressed. The solution is based upon finding a particular joint rate solution and identifying a joint velocity null-space basis through a decomposition of screw coordinates representing the joint axes. Optimal joint rate solutions are formulated in terms of the joint null-space basis. A specification of computational costs for numerical application is presented. The method is shown to be useful for analytical application through example derivations for two 7 revolute jointed manipulators and a platform mounted nonredundant manipulator.

Sign in / Sign up

Export Citation Format

Share Document