We present a general method for worst-case limlt kinematic tolerance analysis: computing the range of variation in the kinematic function of a mecnanism [rom its part tolerance specifications. The method covers fixed and changing contact mechanisms with parametric or geometric part tolerances. We develop a new model of kincmaLic variation, called kinematic tolerance space, that generalizes the ...

This work deals with modeling and tracking of mechanical systems which are given as kinematic chains with restricted degrees of freedom. Such systems may involve many joints, but due to additional restrictions or mechanical properties the joints depend on each other. So-called closed-chain or parallel manipulators are examples for kinematic chains with additional constraints. Though the degrees...

The kinematic sensitivity is a unit-consistent measure that has been recently proposed as a mechanism performance index to compare robot architectures. This paper presents a robust geometric approach for computing this index for the case of planar parallel mechanisms. The physical meaning of the kinematic sensitivity is investigated through different combinations of the Euclidean and infinity n...

The paper proposes a new architecture for a lower exoskeleton with five degrees of freedom (DOF) per each leg, where, the design and synthesis of the kinematic chains is based on human leg parameters in terms of ratios, range of motion, and physical length. This research presents the design and simulation of lower limb exoskeleton for rehabilitation of patients with paraplegia. This work presen...

In this paper, the kinematic synthesis of a four-link mechanism with rolling contacts is investigated. This mechanism comprises a two-fingered gripper and a grasped object. The synthesis equations used for motion generation and function generation are established. The number of free choices in design variables for the kinematic synthesis is also discussed. Furthermore, the optimization-based nu...

In this paper an e cient sequential approach for simulating thermal stresses in brake discs for repeated braking is presented. First a frictional heat analysis is performed by using an Eulerian formulation of the disc. Then, by using the temperature history from the rst step of the sequence, a plasticity analysis with temperature dependent material data is performed in order to determine the co...

In this paper, based on the kinematic accuracy theory and matrix-based system reliability analysis method, a practical method for system reliability analysis of the kinematic performance of planar linkageswith correlated failuremodes is proposed. The Taylor series expansion is utilized to derive a general expression of the kinematic performance errors caused by random variables. A proper limit ...

We present an optimization procedure that uses the Taguchi method to maximize the mean stiffness and workspace of a redundantly actuated parallel mechanism at the same time. The Taguchi method is used to separate the more influential and controllable variables from the less influential ones among kinematic parameters in workspace analysis and stiffness analysis. In the first stage of optimizati...