摘要:

AbstractA trajectory planning approach for controlling flexible manipulators is proposed. It is demonstrated that choosing actual joint angles as the generalized rigid coordinates is the key to applying the proposed approach. From the observation of the special structure of the input matrix, the concepts of motion‐induced vibration and inverse dynamics under a specified motion history of the joints are formed naturally. Based on the above concepts, trajectory planning in joint space is proposed by using the optimization technique to determine the motion of joints along a specified path in joint space or work space and for general point‐to‐point motion. The motion for each joint is assumed to be in a class consisting of a fifth‐order polynomial and a finite terms of Fourier series. This parameterization of motion allows the optimal trajectory planning to be formulated as a standard nonlinear programming problem, which avoids the necessity of solving a two‐point‐boundary‐value problem and using dynamic programming. Setting the accelerations to zero at the initial and the final times is used to obtain smoother motion to reduce the spillover energy into unmodeled high‐frequency dynamics. A penalty term on vibration energy contained in the performance index is used to minimize the vibration of the system modeled by lower frequency only. The final simulation results show the effectiveness of the proposed approach and the advantage for proper trajectory planning. © 2995 John

ISSN:0741-2223    

DOI:10.1002/rob.4620120502

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

年代:1995

数据来源: WILEY

摘要:

AbstractIn this article, the problem of controlling redundant manipulators to reduce collision impact effects is considered, and an augmented kinematics and impedance control scheme is proposed for its solution. The proposed scheme achieves satisfactory performance by minimizing the magnitudes of impulsive forces as well as reducing rebound effects of the end‐effector. In the proposed control scheme, kinematic redundancy is resolved using an augmented kinematics approach where the augmentation of the Jacobian matrix is based on an impact model derived using the Cartesian‐space dynamic model of the manipulator. The proposed impact controller uses a simplified impedance control scheme aimed at reducing impulsive forces as well as rebound effects. The performance of the proposed controller is illustrated by computer simulations. © 2995 John Wiley&Sons,

ISSN:0741-2223    

DOI:10.1002/rob.4620120503

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

年代:1995

数据来源: WILEY

摘要:

AbstractThis article considers the question of position and force control of three‐link elastic robotic systems on a constraint surface in the presence of robot parameter and environmental constraint geometry uncertainties. The approach of this article is applicable to any multi‐link elastic robot. A sliding mode control law is derived for the position and force trajectory control of manipulator. Unlike the rigid robots, sliding mode control of an end point gives rise to unstable zero dynamics. Instability of the zero dynamics is avoided by Controlling a point that lies in the neighborhood of the actual end point position. The sliding mode controller accomplishes tracking of the end‐effector and force trajectories on the constrained surface; however, the maneuver of the arm causes elastic mode excitation. For point‐to‐point control on the constraint surface, a stabilizer is designed for the final capture of the terminal state and vibration suppression. Numerical results are presented to show that in the closed‐loop system position and force control is accomplished in spite of payload and constraint surface geometry uncertainty. © 1995 John Wil

ISSN:0741-2223    

DOI:10.1002/rob.4620120504

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

年代:1995

数据来源: WILEY

摘要:

AbstractPassive approaches for vibration‐free handling of deformable beams are investigated in this article. Dynamic equations of a flexible beam handled by robot end‐effectors are formulated and analyzed first. From the analysis, it is revealed that the inertia forces caused by the beam motion may affect the vibration of the beam in certain motion patterns. Motion trajectories of the end‐effector that lead to a small or no vibration of the beam in these motion patterns are then specified. Because vibrations cannot be totally eliminated even if the vibration‐free motion trajectory is employed, another passive approach is further suggested. The approach employs a rubber pad in parallel with a spring installed on the fingers of the end‐effector. To understand the effectiveness of this passive approach, damped vibration and optimal damping are investigated. Experiments and simulations are conducted to verify the above two methods. The experiments display the vibration‐free motion of the beam using the proposed motion planning strategy. The simulation results demonstrate the effects of the vibration‐free trajectory and the passive damping. © 1995 John W

ISSN:0741-2223    

DOI:10.1002/rob.4620120505

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.4620120501

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

年代:1995

数据来源: WILEY