摘要:

AbstractThis article develops the exact first‐order endpoint Jacobian matrix for a general n‐degrees of freedom tree‐like robot with flexible links. The Jacobian is developed in terms of the joint axes, the link deformations, and the relative position vectors using cross products. To have the correct first‐order endpoint Jacobian matrix, the second‐order kinematics is used to describe a flexible link. Using two local Jacobian matrices enables to write the endpoint Jacobian sub‐matrix associated to a flexible link, which is similar to the column of the Jacobian associated to a joint. An example with a one‐link flexible arm rotating in a vertical plane illustrates the usefulness of the endpoint Jacobian in calculating the torque required to apply an endpoint force and the link deformation resulting from this force. An experimental verification proves the validity of the developed Jacobian and suggests that using only first‐order kinematics results in serious errors in the prediction of the beam's curvatures and deformations © 1995John

ISSN:0741-2223    

DOI:10.1002/rob.4620121102

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

年代:1995

数据来源: WILEY

摘要:

AbstractThis article presents a partial state feedback controller for a rigid‐link flexible‐joint (RLFJ) robot using an observed integrator backstepping approach. The robot controller requires only link position and actuator position measurements, and eliminates the need for measuring link velocity and actuator velocity. The controller uses two exact knowledge, second‐order nonlinear observers to estimate the link and actuator velocities. The overall control system achieves a semiglobal exponential stability result for the link position and velocity tracking errors as well as the velocity observation errors. A stability proof and simulation results for the proposed partial state feedback controller are included in the article. © 1995John Wiley&Son

ISSN:0741-2223    

DOI:10.1002/rob.4620121103

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

年代:1995

数据来源: WILEY

摘要:

AbstractThis article deals with the control of a robot manipulator performing constrained motion in an environment where the constraint function contains uncertainties. The uncertainties are appropriately modeled, and a controller consisting two components, one for positional and velocity tracking, and the other for force regulation, is proposed. The controller contains a nonlinear term that takes the form of a polynomial in the norms of the trajectory and force errors. The coefficients of the nonlinear function are chosen in relation to the bounds on the dynamic parameters of the robot system and an estimate of the bound on the uncertainty in the constraint function. Simulation results show that the modeling is appropriate and the controller is robust against parameter uncertainties ©1995 John Wiley&Sons, Inc

ISSN:0741-2223    

DOI:10.1002/rob.4620121104

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

年代:1995

数据来源: WILEY

摘要:

AbstractA crucial point in developing walking machines is the load to weight ratio. Leg design and in it the drives essentially determine the leg's weight. Therefore it makes sense to optimize the design as well as the best motor‐gear‐combination with respect to power density. Some typical principles of legs have been derived from biological findings, especially for insects. The technical solution was adapted to these principles in an optimal way. The resulting leg achieves a load to weight ratio of approximately six. ©1995 John Wiley&Sons,

ISSN:0741-2223    

DOI:10.1002/rob.4620121105

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

年代:1995

数据来源: WILEY

摘要:

AbstractFuture space systems will use teleoperated robotic systems mounted on flexible bases such as the Shuttle Remote Manipulator System. Due to dynamic coupling, a major control issue associated with these systems is the effect of flexible base vibrations on the performance of the robot. If uncompensated, flexible vibrations can lead to inertial tracking errors and an overall degradation in system performance. One way to overcome this problem is to use kinematically redundant robots. Thus, this article presents research results obtained from locally resolving kinematic redundancies to reduce or damp flexible vibrations. Using a planar, three‐link rigid robot example, numerical simulations were performed to evaluate the feasibility of three vibration damping redundancy control algorithms. Results showed that compared to a zero redundancy baseline, the three controllers were able to reduce base vibration by as much as 90% in addition to decreasing the required amount of joint torque. However, similar to locally optimizing joint torques, excessive joint velocities often occurred. To improve stability, fixed weight, multi‐criteria optimizations were performed. ©1995 John Wiley&Sons,

ISSN:0741-2223    

DOI:10.1002/rob.4620121106

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.4620121101

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

年代:1995

数据来源: WILEY