ABSTRACT This paper deals with the sensitivity analysis of 3-RPR planar parallel manipulators (PPMs). First, the sensitivity coefficients of the pose of the manipulator moving platform to variations in the geometric parameters and in the actuated variables are expressed algebraically. Moreover, two aggregate sensitivity indices are determined, one related to the orientation of the manipulator m...

This paper presents a study of three different Visual Servoing architectures for a planar robot manipulator, comparing their behaviour in achieving a desired goal. The studied architectures were 2D Visual Servoing, 21⁄2D Visual Servoing and Visual Servoing by path planning. The target used in the experiments was planar. Four target points were selected as the visual features. Since the robot is...

In this paper, the static balancing of existing spatial and planar parallel manipulators by the addition of balancing elements is addressed. Static balancing is defined here as the set of conditions on manipulator dimensional and inertial parameters which, when satisfied, ensure that the weight of the links does not produce any force (or torque) at the actuators for any configuration of the man...

The subject of this paper is a special class of closedchain manipulators. First, we analyze a family of twodegree-of-freedom (dof) five-bar planar linkages. Two Jacobian matrices appear in the kinematic relations between the joint-rate and the Cartesian-velocity vectors, which are called the “inverse kinematics” and the “direct kinematics” matrices. It is shown that the loci of points of the wo...

Null space velocity control is essential for achieving good behaviour of a redundant manipulator. Using the dynamically consistent pseudo-inverse, the task and null space motion and forces are decoupled. The paper presents a globally stable null space velocity controller and the gradient projection technique in conjunction with the dynamically consistent pseudo-inverse. The physical meaning and...

An important issue in designing manipulators for dynamic performance is the determination of the acceleration properties of (some reference-point on) the end-effector of the manipulator. Given the dynamical equations of the planar two degree-of-freedom manipulator and a set of constraints on the actuator torques and on the rates-ofchanges of the joint variables, we systematically develop (a) th...

This paper illustrates an application of intelligent control for a planar 3-RRR parallel manipulator. Unlike control of serial manipulators that has been vastly addressed in scientific literature, control of parallel manipulators has been only addressed by few. A GA optimized bi-level tuning fuzzy PD controller is designed here to control the manipulator. In order to consider the maximum allowa...