Rather severe parametric uncertainties and uncertain nonlinearities exist in the dynamic modeling of a parallel manipulator driven by pneumatic muscles. Those uncertainties not only come from the timevarying friction forces and the static force modeling errors of pneumatic muscles but also from the inherent complex nonlinearities and unknown disturbances of the parallel manipulator. In this pap...

This paper concerns the singuIariQ of the HALF parallel manipulato,: a novel three degrees of feedom (DoFs) mechanism, with revolute actuators. The parallel manipulato,: pmposed previousb, consists of a base plate, a movable platform, and three connecting legs. It has the advantages in terms of only single-DoF joints and high rotational capability The parallef manipulator has wide application i...

This paper presents the systematic methods to deal with kinematic analysis of 3-PRS configuration parallel manipulator involving non-linear simultaneous equations. Using the loop closure constraints, three coupled equations are formulated using configuration of the manipulator. Bezout’s resultant and Sylvester method are used to determine roots of three non-linear equations. The tilt of the mov...

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 ...

In order to improve trajectory tracking accuracy for a redundantly actuated parallel manipulator, a so-called augmented nonlinear PD (ANPD) controller based on the conventional dynamic controller is proposed in this paper. The ANPD controller is designed by replacing the linear PD in the augmented PD controller with a nonlinear PD algorithm. The stability of the parallel manipulator system with...

In this paper a general procedure devoted to trajectory optimization is presented. This procedure is used for optimizing the trajectory of a parallel manipulator named CaPaMan (Cassino Parallel Manipulator) by using a performance criterion that includes the mechanical energy and the total traveling time. The resulting scalar objective function is then minimized. The trajectory is represented by...

Parallel mechanisms have the advantages of high rigidity, high precision and fast movement in its workspace. It is a most suitable mechanism to serve as the mini manipulator in a macro/mini manipulator as the mini manipulator needs to have fast response and high resolution in positioning. In this paper, the design of a 3-PUU parallel mechanism to be used as such a mini is presented. Failures ar...

This paper analyzes the singularities of a three degree of freedom (DOF) spatial parallel manipulators utilizing line geometry and linear complex approximation. First, the 6 · 6 matrix, mapping external wrenches acting on the moving platform to internal forces/moments at the manipulator s joints, is derived as a set of six governing lines. By analyzing the dependencies of these lines, all singu...

This work proposes direction-dependent Jacobian indices that allow tackling the performance evaluation and dimensional synthesis of parallel manipulators. These indices characterize the kinetostatic capabilities of a manipulator along and about each direction of the Cartesian space and are more likely to help the designer to achieve an assessment of different geometries without having to resort...

A parallel manipulator is naturally associated with a set of constraint functions defined by its closure constraints. The differential forms arising from these constraint functions completely characterize the geometric properties of the manipulator. In this paper, using the language of differential forms, we provide a thorough geometric study on the various types of singularities of a parallel ...