This paper investigates the stiffness modelling of a 3-DOF parallel manipulator with two additional legs. The stiffness model in six directions of the 3-DOF parallel manipulator with two additional legs is derived by performing condensation of DOFs for the joint connection and treatment of the fixed-end connections. Moreover, this modelling method is used to derive the stiffness model of the ma...

Abstract—This paper presents the trajectory tracking control of a spatial redundant hybrid manipulator. This manipulator consists of two parallel manipulators which are a variable geometry truss (VGT) module. In fact, each VGT module with 3-degress of freedom (DOF) is a planar parallel manipulator and their operational planes of these VGT modules are arranged to be orthogonal to each other. Als...

This paper presents the concept of a cable-manipulator based 6-DOF hardware-in-the-loop (HIL) dynamics simulation system for testing and verification of microgravity contact-dynamics behavior of a space system. It then focuses on the inverse dynamics problem of the 6-DOF cable-driven manipulator which is designed for the simulation system. Accurate modeling and solution of the inverse dynamics ...

Planning robot trajectory is a complex task that plays a significant role in design and application of robots in task space. The problem is formulated as a trajectory optimization problem which is fundamentally a constrained nonlinear optimization problem. Open-loop optimal control method is proposed as an approach for trajectory optimization of cable parallel manipulator for a given two-end-po...

The dynamic formulation and performance evaluation of the redundant parallel manipulator are presented in this paper. By means of the principle of virtual work and the concept of link Jacobian matrices, the inverse dynamic model of the redundant parallel manipulator is set up. It consists of six linear consistent equations with eight unknown quantities. Then, the optimum solution of the actuati...

In this paper, the authors study the kinematic isotropic configuration of spatial cable-driven parallel robots by means of four different methods, namely, (i) symbolic method, (ii) geometric workspace, (iii) numerical workspace and global tension index (GTI), and (iv) numerical approach. The authors apply the mentioned techniques to two types of spatial cable-driven parallel manipulators to obt...

In this work, the 3-RPRR, a new kinematically redundant planar parallel manipulator with six degrees of freedom, is presented. First the manipulator is introduced and its inverse displacement problem discussed. Then, all types of the singularities of the 3-RPRR manipulator are analysed and demonstrated. Thereafter, the reachable and dexterous workspaces are obtained and compared with those of t...