In this paper, the kinematics of the parallel modules of a variable-geometry-truss (VGT) manipulator is studied, at the position level, by a multilayer neural network and via the kinematics of an equivalent serial mechanism. We show that the trained network provides good estimate of the exact solution to the kinematics of each module. Moreover, this indirect approach allows us to efficiently project the practical limits on the displacement of actuators onto the backbone-curve posture. This feature of the proposed approach is very attractive for the real-time configuration control and motion planning of a VGT manipulator, that comprises a large number of parallel modules connected in series.

The macroscopic geometric shape of a hyper-redundant manipulator can be described by a curve which is called the reference or backbone curve (BBC). In this paper, a discrete model with compliance is developed for the BBC that is a practical approximation to a continuous elastic cord. Based on the proposed model, kinematic redundancy is resolved through shape optimization: minimizing the elastic potential energy of the BBC. The formulation introduced here is general and can be efficiently used for the configuration control of hyper-redundant manipulators. Moreover, the proposed discrete model is well suited for a class of variable-geometry-truss (VGT) manipulators that are made up of double-octahedral modules. The effectiveness of the model is verified by numerical simulations and hardware experiments.

The subject of this paper is the kinematic analysis of a hand controller at the displacement level. The device is a six degree-of-freedom hybrid mechanism comprising two modules, each with three degrees of freedom. Based on the proposed kinematic model of the mechanism, we derive the necessary relations between the Cartesian coordinates of the end-effector and the joint variables.

This paper presents a spline-based solution method for the inverse kinematics of hyper-redundant manipulators. The reference or backbone curve, that describes the macroscopic geometric shape of the manipulator is modelled by cubic and quintic piecewise parametric spline segments. A procedure for the coordinate frame distribution is proposed that allows any desirable rotation to be deployed about the backbone curve. Moreover, control points are used to determine the optimum shape and to change the length of the manipulator. The proposed solution method is general and applicable to non-extensible as well as extensible planar or spatial hyper-redundant manipulators with different morphologies.

In this paper we study the velocity and acceleration relations of a novel redundant parallel manipulator. Through this study, we derive the Jacobian matrices of the inverse and direct velocity problems. Moreover, we introduce two practical designs that are kinematically equivalent to the ideal manipulator. The proposed manipulator has potential to be used in a wide range of applications from space robotics to highly dexterous flight simulators.>

Presented in this paper is a new platform-type manipulator that is parallel and kinematically redundant. The use of redundancy not only increases the workspace, but also helps in coping with singularities and improves dexterity. A complete kinematic model of the structure is presented in this paper, that is used for its mobility, and its direct and inverse position analyses.>