scholarly journals Motion Planning for Mobile Manipulators along Given End-effector Paths

2006 ◽  
Author(s):  
G. Oriolo ◽  
C. Mongillo
Keyword(s):  
Motion Planning ◽  
Mobile Manipulators ◽  
End Effector

Adaptive motion selection for online hand–eye calibration

Robotica ◽  
2007 ◽  
Vol 25 (5) ◽  
pp. 529-536
Author(s):  
Jing Zhang ◽  
Fanhuai Shi ◽  
Yuncai Liu
Keyword(s):  
Motion Planning ◽  
Dynamic Threshold ◽  
Selection Algorithm ◽  
Robot System ◽  
End Effector ◽  
Threshold Determination ◽  
Robot Gripper ◽  
Adaptive Motion ◽  
Selection For ◽  
Relative Pose

SUMMARYWhile a robot moves, online hand–eye calibration to determine the relative pose between the robot gripper/end-effector and the sensors mounted on it is very important in a vision-guided robot system. During online hand–eye calibration, it is impossible to perform motion planning to avoid degenerate motions and small rotations, which may lead to unreliable calibration results. This paper proposes an adaptive motion selection algorithm for online hand–eye calibration, featured by dynamic threshold determination for motion selection and getting reliable hand–eye calibration results. Simulation and real experiments demonstrate the effectiveness of our method.

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.

New repetitive motion planning scheme with cube end-effector planning precision for redundant robotic manipulators

Robotica ◽  
2021 ◽  
pp. 1-22
Author(s):  
Limin Shen ◽  
Yuanmei Wen
Keyword(s):  
Theoretical Analysis ◽  
Motion Planning ◽  
Robotic Manipulators ◽  
Robotic Manipulator ◽  
Repetitive Motion ◽  
End Effector ◽  
Difference Formula ◽  
Planning Scheme ◽  
Simulation Results ◽  
The Difference

Abstract Repetitive motion planning (RMP) is important in operating redundant robotic manipulators. In this paper, a new RMP scheme that is based on the pseudoinverse formulation is proposed for redundant robotic manipulators. Such a scheme is derived from the discretization of an existing RMP scheme by utilizing the difference formula. Then, theoretical analysis and results are presented to show the characteristic of the proposed RMP scheme. That is, this scheme possesses the characteristic of cube pattern in the end-effector planning precision. The proposed RMP scheme is further extended and studied for redundant robotic manipulators under joint constraint. Based on a four-link robotic manipulator, simulation results substantiate the effectiveness and superiority of the proposed RMP scheme and its extended one.

Enhancing kinematic accuracy of redundant wheeled mobile manipulators via adaptive motion planning

Mechatronics ◽  
2021 ◽  
Vol 79 ◽  
pp. 102639
Author(s):  
Hongjun Xing ◽  
Ali Torabi ◽  
Liang Ding ◽  
Haibo Gao ◽  
Weihua Li ◽  
...  
Keyword(s):  
Motion Planning ◽  
Mobile Manipulators ◽  
Kinematic Accuracy ◽  
Adaptive Motion ◽  
Wheeled Mobile Manipulators

Optimal Base Placement and Motion Planning for Mobile Manipulators

2012 ◽  
Author(s):  
Bin Du ◽  
Jing Zhao ◽  
Chunyu Song
Keyword(s):  
Motion Planning ◽  
Great Influence ◽  
Initial Point ◽  
Mobile Manipulator ◽  
Target Point ◽  
Mobile Manipulators ◽  
Redundant Manipulator ◽  
Self Motion ◽  
The Given ◽  
Manipulation Capability

A mobile manipulator typically consists of a mobile platform and a robotic manipulator mounted on the platform. The base placement of the platform has a great influence on whether the manipulator can perform a given task. In view of the issue, a new approach to optimize the base placement for a specified task is proposed in this paper. Firstly, the workspace of a redundant manipulator is investigated. The manipulation capability of the redundant manipulator is maximized based on the manipulability index through the joint self-motion of the redundant manipulator. Then the maximum manipulation capability in the specified work point is determined. Next, the relative manipulability index (RMI) is defined for analyzing manipulation capability of the manipulator in its workspace, and the global manipulability map (GMM) is presented based on the above measure. Moreover, the optimal base placement related to the given task is obtained, and the motion planning is implemented by an improved rapidly-exploring random tree (RRT) algorithm with the RMI, which can enhance the manipulation capability from the initial point to the target point. Finally, the feasibility of the proposed algorithm is illustrated with numerical simulations and experiments on the mobile manipulator.

End-effector Motion Planning for One-Link Flexible Robot

2000 ◽  
Vol 33 (27) ◽  
pp. 315-320 ◽  
Author(s):  
M. Benosman ◽  
G. Le Vey
Keyword(s):  
Motion Planning ◽  
Flexible Robot ◽  
End Effector

Autonomous Rectilinear Motion Planning for a Spatial Robot: Path Planning for a Spatial 4R Manipulator With a Single Spherical Obstacle Inside the Workspace

1992 ◽  
Vol 114 (4) ◽  
pp. 559-563 ◽  
Author(s):  
Menq-Dar Shieh ◽  
J. Duffy
Keyword(s):  
Path Planning ◽  
Motion Planning ◽  
Free Path ◽  
Efficient Algorithm ◽  
Rectilinear Motion ◽  
Robot Path Planning ◽  
End Effector ◽  
Truncated Pyramid ◽  
Robot Path

This is the first of a series of papers dealing with the path planning for a spatial 4R robot with multiple spherical obstacles inside the workspace. In this paper, a time efficient algorithm has been developed to determine a collision free path for the end effector tip of the robot with a single spherical obstacle inside the workspace. A truncated pyramid and a right circular torus are used to model the nonreachable workspaces of the end effector tip of the robot. The problem of guiding the spatial 4R manipulator while avoiding a spherical obstacle is reduced to moving a point while avoiding a truncated pyramid and/or a right circular torus inside the workspace. The point represents the tip of the end effector of the manipulator. This approach produces an efficient algorithm for determining a collision free path. The algorithm has been successfully developed and implemented in the Silicon Graphics 4D-70GT workstation to verify the results.

Motion Planning of Tomato Harvesting Manipulators with 7 DOF

2010 ◽  
Vol 97-101 ◽  
pp. 2840-2844 ◽  
Author(s):  
Xi Feng Liang ◽  
Yong Wei Wang
Keyword(s):  
Motion Planning ◽  
Degrees Of Freedom ◽  
Numerical Solutions ◽  
Optimization Technique ◽  
Tracking Error ◽  
Absolute Error ◽  
Initial Position ◽  
End Effector ◽  
Mathematical Relationships ◽  
Computation Load

This work presents a motion planning approach for tomato harvesting manipulators with seven degrees of freedom (7 DOF) based on an optimization technique and alternative method. It is to find optimal joint perturbations during the path planning so that a manipulator reaches a goal from an initial position with high accuracy. The optimization model consists of the objective function defined by the tracking error and the representation of a set of mathematical relationships that describe the kinematic restrictions of the manipulator. In this method, only a forward kinematics is used and the complex mathematics in numerical solutions of an inverse kinematics is avoided to reduce the computation load. Simulation results show that the tomato harvesting manipulator can move the end-effector to the target from an initial position along a specified geometric trajectory in its workspace. Simultaneously, the joint displacements vary smoothly within their limits during tracking. The position absolute error, moving velocity and precision of the end-effector are 0.53mm, 0.18m/s and 3.75% respectively, which fulfill the requirements of tomato picking with well working efficiency.

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