The paper presents a new stiffness modeling method for overconstrained parallel manipulators with flexible links and compliant actuating joints. It is based on a multidimensional lumped-parameter model that replaces the link flexibility by localized 6-dof virtual springs that describe both translational/rotational compliance and the coupling between them. In contrast to other works, the method ...

We propose a new model for robot manipulators with rigid links and flexible joints. Our model is expressed in Cartesian dependent coordinates which represent the positions, orientations and velocities of the links and the rotors, as opposed to independent generalized coordinates in which classical “Lagrangian” models are defined. The model consists of a set of dynamics equations and holonomic c...

This paper addresses the problem of impedance control for flexible joint robots based on a singular perturbation approach. Some aspects of the impedance controller, which turned out to be of high practical relevance during applications are then addressed, such as the implementation of nullspace stiffness for redundant manipulators, the avoiding of mass matrix decoupling and the related design o...

This paper presents an end-point position measurement method for long-reach flexible manipulators using a landmark tracking system (LTS). The LTS is based on a computer vision system designed for the tracking of retroreflective landmarks. Hardware and software components of the LTS are described and the calibration procedure and sensing performance are discussed. Two methods are suggested to im...

Trajectory tracking is a common application method for manipulators. However, the performance hard to improve if manipulators contain flexible joints and mismatched uncertainty, especially when trajectory nonholonomic. On basis of Udwadia–Kalaba Fundamental Equation (UKFE), prescribed position or velocity trajectories are creatively transformed into second-order standard differential form. The ...

We present a modeling framework which combines kinematic and dynamic aspects of a motion planning task. This paper presents the control algorithms for multiple mobile manipulators cooperatively grasping and transporting an object. The planning and control tasks are decentralized, and the framework explicitly incorporates the protocols used to coordinate the robots in the team. The framework is ...

In this paper, we consider the state estimation problem for flexible joint manipulators that involve nonlinear characteristics in their stiffness. The two key ideas of our design are that (a) an accelerometer is used in order that the estimation error dynamics do not depend on nonlinearities at the link part of the manipulators and (b) the model of the nonlinear stiffness is indeed a Lipschitz ...

In this paper, finding Dynamic Load Carrying Capacity (DLCC) of flexible link manipulators in point to-point motion was formulated as an optimal control problem. The finite element method was employed for modelling and deriving the dynamic equations of the system. The study employed indirect solution of optimal control for system motion planning. Due to offline nature of the method, many diffic...