Decentralized Kinematic Control of a Cooperating System of Mobile Manipulators

2002 ◽  
Author(s):  
Michel Abou-Samah ◽  
Venkat Krovi
Keyword(s):  
Degree Of Freedom ◽  
Modular System ◽  
Mobile Manipulator ◽  
Mobile Manipulators ◽  
Relative Positioning ◽  
Mobile Platforms ◽  
Relative Configuration ◽  
Kinematic Control ◽  
Common Object ◽  
Positioning Errors

In this paper, we examine the development of a decentralized control framework for a modular system of wheeled mobile manipulators that can team up to cooperatively transport a large common object. Each individually autonomous mobile manipulator consists of a differentially-driven wheeled mobile robot (WMR) with a passive, two-degree-of-freedom, planar, revolute-jointed arm mounted in the plane parallel to the base of the WMR. The composite multi-degree-of-freedom vehicle, formed by placing a common object on the end-effector of two (or more) such mobile manipulator systems, possesses the ability to accommodate relative positioning errors of the mobile bases as well as change its relative configuration. Particular attention is paid for the development of kinematic control schemes for mobile manipulators, which take into account the non-holonomic constraints of the base and the presence of passive joints in the manipulator system. The control scheme developed for the individual mobile manipulators is then adapted for the decentralized kinematic control of two mobile manipulators carrying a common object along a desired trajectory. Experimental evaluation of the performance of the resulting approach and the ability of the overall collaborating system to accommodate, detect and correct for relative positioning errors between the mobile platforms is also presented.

Manipulability-based configuration evaluation of cooperative payload transport by mobile manipulator collectives

Robotica ◽  
2006 ◽  
Vol 25 (1) ◽  
pp. 29-42 ◽  
Author(s):  
Chin Pei Tang ◽  
Venkat N. Krovi
Keyword(s):  
Kinematic Model ◽  
Nonholonomic Constraints ◽  
System Level ◽  
Mobile Manipulator ◽  
Mobile Manipulators ◽  
Cooperative System ◽  
Relative Configuration ◽  
Positioning Errors ◽  
Kinematic Loops ◽  
End Effectors

In this paper, we focus on the development of a quantitative performance analysis framework for a cooperative system of multiple wheeled mobile manipulators physically transporting a common payload. Each mobile manipulator module consists of a differentially driven wheeled mobile robot (WMR) with a mounted planar three-degree-of-freedom (DOF) revolute-jointed manipulator. A composite cooperative system is formed when a payload is placed at the end-effectors of many such modules. The system possesses the ability to change its relative configuration as well as to accommodate relative positioning errors of the wheeled agents. However, the combination of nonholonomic constraints due to the mobile bases, holonomic constraints due to the closed kinematic loops, and the different joint-actuation schema (active/passive/locked) within the system requires careful quantitative evaluation to efficiently realize the payload manipulation task. Hence, in this paper, we extend the differential kinematic model for treatment of constrained articulated mechanical systems to formulate a framework to include both the mixture effect of holonomic/nonholonomic constraints and the different possible joint-actuation schema in our system. The system-level performance is then examined quantitatively by the manipulability measure in terms of isotropy index with representative case studies.

scholarly journals On path following control of nonholonomic mobile manipulators

2009 ◽  
Vol 19 (4) ◽  
pp. 561-574 ◽  
Author(s):  
Alicja Mazur ◽  
Dawid Szakiel
Keyword(s):  
Control Algorithm ◽  
Dynamic Control ◽  
Path Following ◽  
Mobile Manipulator ◽  
Mobile Manipulators ◽  
Control Laws ◽  
Kinematic Control ◽  
Motion Constraints ◽  
Path Following Control ◽  
Cascade Structure

On path following control of nonholonomic mobile manipulatorsThis paper describes the problem of designing control laws for path following robots, including two types of nonholonomic mobile manipulators. Due to a cascade structure of the motion equation, a backstepping procedure is used to achieve motion along a desired path. The control algorithm consists of two simultaneously working controllers: the kinematic controller, solving motion constraints, and the dynamic controller, preserving an appropriate coordination between both subsystems of a mobile manipulator, i.e. the mobile platform and the manipulating arm. A description of the nonholonomic subsystem relative to the desired path using the Frenet parametrization is the basis for formulating the path following problem and designing a kinematic control algorithm. In turn, the dynamic control algorithm is a modification of a passivity-based controller. Theoretical deliberations are illustrated with simulations.

Dynamic Modeling of a Non-Redundant Spatial Mobile Manipulator

2001 ◽  
Author(s):  
James M. Stiles ◽  
Jae H. Chung ◽  
Steven A. Velinsky
Keyword(s):  
High Speed ◽  
Robot Manipulator ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
High Mobility ◽  
Mobile Manipulator ◽  
Mobile Manipulators ◽  
Mobile Platforms ◽  
Wheel Slip ◽  
Kinematic Models

Abstract Mobile manipulators are comprised of robot manipulators mounted upon mobile platforms which allow for both high mobility and dexterous manipulation ability. Although much research has been performed in the area of motion control of mobile manipulators, previous developed models are typically simplified and assume only planar motion and/or holonomic constraints. In this work, the equations of motion of a three dimensional non-redundant wheeled-vehicle based mobile manipulator system are developed using a Newton-Euler formulation. This model incorporates a complex tire model which accounts for tire slip and is thus applicable to high speed and high load applications. The model is systematically exercised to examine the dynamic interaction effects between the mobile platform and the robot manipulator, to illustrate the effects of wheel slip on system performance, and to establish bounds on the efficacy of the simplified existing kinematic models.

Manipulability-Based Configuration Evaluation of Cooperative Payload Transport by Mobile Robot Collectives

2004 ◽  
Author(s):  
Chin Pei Tang ◽  
Venkat Krovi
Keyword(s):  
Mobile Robot ◽  
Single Agent ◽  
System Level ◽  
Mobile Manipulator ◽  
Mobile Manipulators ◽  
Cooperative System ◽  
Kinematic Modeling ◽  
Relative Configuration ◽  
Holonomic Constraints ◽  
Kinematic Loops

Interest in cooperative systems typically arises when certain tasks are either too complex to be performed by a single agent or when there are distinct benefits that accrue by cooperation of many simple agents. A quantitative examination of performance enhancement, due to the implementation of cooperation, is critical. In this paper, we focus on the development of a quantitative performance-analysis framework for a cooperative system with multiple wheeled mobile manipulators physically transporting a common payload. Each mobile manipulator module consists of a differentially-driven wheeled mobile robot with a mounted planar three-degree-of-freedom (d.o.f.) manipulator. A composite cooperative system is formed when a payload is placed at the end-effectors of multiple such modules. Such a system possesses the ability to change its relative configuration as well as accommodate relative positioning errors of the mobile bases. However, the combination of nonholonomic constraints due to the mobile bases, holonomic constraints due to the closed kinematic loops formed and the varying actuation of the joints within the cooperative system requires careful treatment for realizing the payload transport task. In this paper, we will analyze the cooperative composite system within a constrained mechanical system framework, by extending methods developed for treatment of articulated-closed-chain systems. Specifically, we will focus on the velocity-level kinematic modeling, while taking into account the nonholonomic/holonomic constraints and different joint-actuation schemes within the system. We then examine the applicability of a manipulability measure (isotropy index), to quantitatively analyze the system-level performance of the cooperative system, with these different joint-actuation schemes, with representative case-studies.

A Co-operative Transferring Task by Mobile Manipulators

2000 ◽  
Vol 12 (6) ◽  
pp. 712-717
Author(s):  
Kazuya Yasui ◽  
◽  
Toshiyuki Murakami ◽  
Kouhei Ohnishi
Keyword(s):  
Trajectory Planning ◽  
Null Space ◽  
Internal Force ◽  
Mobile Manipulator ◽  
Mobile Manipulators ◽  
Positioning Errors ◽  
Force Relation ◽  
End Effectors ◽  
Computational Analyses ◽  
Complicated Task

In this paper, a method of grasping and transferring a large object by cooperative motion of multiple manipulators is introduced. To implement the task with mobile manipulators, the compliance of the grasping system between the object and end-effectors is needed. It enables us to avoid excessive internal force due to mutual positioning errors. However, the simple way of trajectory planning of the system is also required. Because the trajectory planning used to be given to each manipulator, it has been very complicated task to design the desired trajectories for each mobile manipulator. Thus this paper adopt the control algorithm with respect to objects to reduce the amount of planning tasks. The static relation between the object and end-effectors is introduced to solve the issues above. It combines the force reference of end-effectors and that of an object with static analysis of force. With this algorithm, the motion of an object is distributed to each end-effector. Then the grasping is projected to the null space of this static force relation. For confirmation of the proposed method, computational analyses are implemented and shown.

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.

Linear Algebra Applied to Kinematic Control of Mobile Manipulators

2017 ◽  
pp. 297-306
Author(s):  
Víctor H. Andaluz ◽  
Edison R. Sásig ◽  
William D. Chicaiza ◽  
Paola M. Velasco
Keyword(s):  
Linear Algebra ◽  
Mobile Manipulators ◽  
Kinematic Control

Determination of the base position and working area for mobile manipulators

2016 ◽  
Vol 36 (1) ◽  
pp. 80-88 ◽  
Author(s):  
Shunan Ren ◽  
Xiangdong Yang ◽  
Jing Xu ◽  
Guolei Wang ◽  
Ying Xie ◽  
...  
Keyword(s):  
Operation Mode ◽  
Mobile Manipulator ◽  
Planning Problem ◽  
Mobile Manipulators ◽  
Line Planning ◽  
Content Type ◽  
Practical Applications ◽  
Base Position ◽  
Intersection Area ◽  
Intersection Line

Purpose – The purpose of this paper is to determine the base position and the largest working area for mobile manipulators. The base position determines the workspace of the mobile manipulator, particularly when the operation mode is intermittent (i.e. the mobile platform stops when the manipulator conducts the task). When the base of the manipulator is in the intersection area of the Base’s Workable Location Spaces (BWLSes), the end effector (EE) can reach all path points. In this study, the intersection line of BWLSes is calculated numerically, and the largest working area is determined using the BWLS concept. The performance of this method is validated with simulations on specific surface segments, such as plane, cylinder and conical surface segments. Design/methodology/approach – The BWLS is used to determine the largest working area and the base position in which the mobile manipulator can reach all path points with the objective of reducing off-line planning time. Findings – Without considering the orientation of the EE, the base position and the working area for the mobile manipulator are determined using the BWLS. Compared to other methods, the proposed algorithm is beneficial when the planning problem has six dimensions, ensuring the reachability and stability of the EE. Originality/value – The algorithm needs no manual configuration, and its performance is investigated for typical surfaces in practical applications.

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