In this paper we introduce two new posture-dependent performance indices for 6dof UPS and 3-dof RPR parallel manipulators. One is based on an object-oriented metric in the workspace (end-effector dependent) and the other one takes the angular velocities of the passive joints into consideration (end-effector independent). Both newly defined indices are invariant under rigid-body motions and simi...

Natural orifice endoscopic surgery can enable incisionless approaches, but a major challenge is the lack of small and dexterous instrumentation. Surgical robots have the potential to meet this need yet often disrupt the clinical workflow. Hand-held robots that combine thin manipulators and endoscopes have the potential to address this by integrating seamlessly into the clinical workflow and enh...

A mixed Optimal/robust control is proposed is this paper for the tracking of rigid robotic systems under parametric uncertainties and external perturbations. The design objective is that under a prescribed disturbance norm level, an optimal control system is to be designed as well as a robust control to overcome the effect of uncertainties. The optimal control is based on the solution of a nonl...

Operational problems with robot manipulators in space relate to several factors, most importantly, structural flexibility and subsequent difficulties with their position control. In this paper we present control methods for endpoint tracking of a 12 6 12 6 m2 trajectory by a two-link robot manipulator. Initially, a manipulator with rigid links is modeled using inverse dynamics, a linear quadrat...

This paper focuses on parameter identification of a target tracker robot possessing flexible joints using particle swarm optimization (PSO) algorithm. Since, belt and pulley mechanisms are known as flexible joints in robotic systems, their elastic behavior affecting a tracker robot is investigated in this work. First, dynamic equations governing the robot behavior are extracted taking into acco...

This paper reports the experimental results of a novel method to calibrate geometric errors of multi-axis robotic manipulators. The method proposed by the authors is based on a least-square estimation of the rotation matrix of a rigid body in three-dimensional Cartesian space. The error is filtered by hnposing the orthogonality constraint on the rotation matrix, using the polar-decomposition th...

Flexible-link robotic manipulators are mechanical devices whose control can be rather challenging, among other reasons because of their intrinsic under-actuated nature. This chapter presents various experimental studies of diverse robust control schemes for this kind of robotic arms. The proposed designs are based on several control strategies with well defined theoretical foundations whose eff...

We have developed a planner for redundant manipula-tors that is fast, eeective and versatile, based on the idea of treating each link of a rigid-linked robot as if it were slightly exible and under the innuence of a potential eld. We describe the extensions to the basic method that allow it to plan paths for manipulators with revolute joints (linear and spherical joints having been covered in a...

In this paper is presented the development of an indirect force control for robot manipulators with elastic joints employed in machining tasks. Based on the study of centralized compliance control for rigid manipulators, it is proposed an extension for robots with torsional flexibility in the joints structured as a cascade control. Additionally, it is proposed a reduced force model, based on ex...

A methodology for the formulation of dynamic equations of motion of a serial flexible-link manipulator using the decoupled natural orthogonal complement (DeNOC) matrices, introduced elsewhere for rigid links, is presented in this paper. First, the Euler Lagrange (EL) equations of motion of the system at hand are written. Then, using the DeNOC matrices associated with the velocity constraints of...