Closed loop motion planning of cooperating mobile robots using graph connectivity

2008 ◽  
Vol 56 (4) ◽  
pp. 373-384 ◽  
Author(s):  
Guilherme Augusto Silva Pereira ◽  
Vijay Kumar ◽  
Mario Fernando Montenegro Campos
Keyword(s):  
Motion Planning ◽  
Mobile Robots ◽  
Closed Loop ◽  
Graph Connectivity ◽  
Loop Motion

Semiglobal Stabilization for Nonholonomic Mobile Robots Based on Dynamic Feedback With Inputs Saturation

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Hua Chen ◽  
Chaoli Wang ◽  
Liu Yang ◽  
Dongkai Zhang
Keyword(s):  
Mobile Robots ◽  
Finite Time ◽  
Closed Loop ◽  
Kinematic Model ◽  
Loop System ◽  
Control Technique ◽  
Dynamic Feedback ◽  
Closed Loop System ◽  
Nonholonomic Mobile Robots ◽  
Semiglobal Stabilization

This paper investigates the semiglobal stabilization problem for nonholonomic mobile robots based on dynamic feedback with inputs saturation. A bounded, continuous, time-varying controller is presented such that the closed-loop system is semiglobally asymptotically stable. The systematic strategy combines finite-time control technique with the virtual-controller-tracked method, which is similar to the back-stepping procedure. First, the bound-constrained smooth controller is presented for the kinematic model. Second, the dynamic feedback controller is designed to make the generalized velocity converge to the prespecified kinematic (virtual) controller in a finite time. Furthermore, the rigorous proof is given for the stability analysis of the closed-loop system. In the mean time, the position and torque inputs of robots are proved to be bounded at any time. Finally, the simulation results show the effectiveness of the proposed control approach.

On the elimination of branching in the synthesis of spatial single-loop mechanisms with lower pairs

Robotica ◽  
1988 ◽  
Vol 6 (2) ◽  
pp. 149-154
Author(s):  
George N. Sandor ◽  
Yongxian Xu ◽  
Tzu-Chen Weng
Keyword(s):  
Closed Loop ◽  
End Effector ◽  
Single Loop ◽  
Spatial Mechanism ◽  
The Relationship ◽  
Motion Generator ◽  
Loop Motion

SUMMARYA single-loop spatial mechanism kinematically becomes an open robot, if we separate the grounded joint of the input link which may then be considered as the end effector of the robot. Any position of the end-effector within the workspace of such an open robot can be reached via a number of different configurations of the links. These configurations are called “branches” of the open robot for that particular position of the end effector.If the open robot is now stretched to a limiting position by a force exerted on the end effector, all the possible branches of the mechanism approach each other. When they become coincident, they form the “limiting configuration”. Any two related branches are at opposite sides of the limiting configuration. From the relationship between the links in th elimiting configuration and in related branches, conditions for aviodance of branching of the original closed-loop mechanism can be obtained. This is necessary in order to assure that a set of consistent relative displacements are specified for the open robot to move displacements are specified for the open robot to move toward the desired end-effector position without jumping from one branch to another. As for the closed-loop mechanism, open robot branching aviodance ensures that a desired sequence of positions of a particular floating link in the loop will be generated without changing the branch of the link configuration.In this paper, the above approach is applied to RSSR, RRSC, RRSRR, RRRRRRR and RPCRRR spatial closed-loop motion-generator mechanisms and the corresponding conditions for aviodance of branching in the synthesis of the mechanisms are derived.

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