摘要:

AbstractReal‐time issues are becoming more and more important in robot programming. When a 6‐dof manipulator is used, planning obstacle‐avoiding paths is a time‐consuming activity, usually done in simulation. We present the geometric models and the reasoning techniques we have implemented while realizing a gross motion planner for a manipulator with six revolute joints. First, construction of a problem‐oriented representation of the robot working space is explained. Then, the actual trajectory research carried out in our C‐space representation is described. The whole C‐space is not calculated; instead, a sequential strategy is used to determine the C‐space only for the first two links. Our approximation of the obstacles, which occupy fixed and known positions, greatly speeds the computation, allowing us to reduce the problem to planar geometric reasoning. The work is not limited to theoretical studies or simulations; experiments have been run very thoroughly, with various tests, on a PUMA robot to assess the real efficiency and usability of our software. The method applies to robots in a fixed and known environment. © 3995 John

ISSN:0741-2223    

DOI:10.1002/rob.4620120202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe two‐level hierarchical control scheme is adopted to solve a dual‐chain robotic system formed by two redundant manipulators grasping a common object with hard point contacts. The upper‐level coordinator gathers all the necessary information to resolve the force distribution problem so as to generate all the desired contact forces With all the desired contact forces being specified, the dynamics of each chain are decoupled. Therefore, the lower‐level local control problem can be treated as a general open‐chain redundant manipulator problem. Furthermore, the Compact‐Dual LP method is applied to resolve the upper‐level coordination problem; while the Compact QP method associated with the computed torque control method is adopted to solve the redundant manipulator problem. To obtain proper simulation results, the simulated actual contact forces are formulated and the corresponding simulation problem of the closed‐chain robotic system is also completely solved in the article. Simulation results show that the two‐level hierarchical control scheme is an effective and efficient algorithm for resolving the large‐scale control problem of multiple‐chain robotic systems. © 199

ISSN:0741-2223    

DOI:10.1002/rob.4620120203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe problem of part mating and assembly with close tolerances has been addressed in the past by active or passive compliance and by force/position control. With ambient sensor and transmission noise and with imprecise measurements it is often difficult to attain high precision in manipulator positioning. In this article, a position‐sensing wrist using simple strain gauges is described. A fuzzy logic algorithm to ascertain the positional error during an unsuccessful assembly attempt is explained. The results obtained by using this wrist and the fuzzy logic algorithm to reposition a manipulator for precision assembly are presented and discussed. © 1995 John Wiley&Sons, I

ISSN:0741-2223    

DOI:10.1002/rob.4620120204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractIn this article, a fast approach for robust trajectory planning, in the task space, of redundant robot manipulators is presented. The approach is based on combining an original method for obstacle avoidance by the manipulator configuration with the traditional potential field approach for the motion planning of the end‐effector. This novel method is based on formulating an inverse kinematics problem under an inexact context. This procedure permits dealing with the avoidance of obstacles with an appropriate and easy to compute null space vector; whereas the avoidance of singularities is attained by the proper pseudoinverse perturbation. Furthermore, it is also shown that this formulation allows one to deal effectively with the local minimum problem frequently associated with the potential field approaches. The computation of the inverse kinematics problem is accomplished by numerically solving a linear system, which includes the vector for obstacle avoidance and a scheme for the proper pseudoinverse perturbation to deal with the singularities and/or the potential function local minima. These properties make the proposed approach suitable for redundant robots operating in real time in a sensor‐based environment. The developed algorithm is tested on the simulation of a planar redundant manipulator. From the results obtained it is observed that the proposed approach compares favorably with the other approaches that have recently been proposed. © 1995 John Wiley&Sons,

ISSN:0741-2223    

DOI:10.1002/rob.4620120205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

ISSN:0741-2223    

DOI:10.1002/rob.4620120201

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY