Kinodynamic rapidly-exploring random tree (RRT) planners are effective tools for finding feasible trajectories in many classes of robotic systems. However, they hard to apply systems with closed-kinematic chains, like parallel robots, collaborative arms manipulating an object, or legged robots keeping their feet contact the environment. The state space such is implicitly-defined manifold that c...

An analytical method is presented to obtain all surfaces enveloping the workspace of a general n degree-of-freedom mechanism with non-unilateral constraints. The method is applicable to kinematic chains that can be modeled using the Denavit-Hartenberg representation method for serial kinematic chains or its modification for closed-loop kinematic chains. The method developed is based upon analyt...

Maximizing the use of dual-arm robotic systems requires the development of planning algorithms analogous to those available for single-arm operations. In this paper, the global properties of the configuration spaces of planar n-bar mechanisms (i.e., kinematic chains forming a single closed loop) are used to design a complete motion planning algorithm. Numerical experiments demonstrate the algor...

Background Every foot muscle crosses and acts upon multiple joints. The close association of foot bones and their supportive ligaments creates several closed kinematic chains. The movement of one bone necessitates the movement of several others. Terms that describe foot motion do not seem to account for these correlated motions. This presentation shows that “plantarflexion-dorsiflexion” necessi...

In formulating the stability problem for an infinite chain of cars, state space is traditionally taken to be the Hilbert space `, wherein the displacements of cars from their equilibria, or the velocities from their equilibria, are taken to be square summable. But this obliges the displacements or velocity perturbations of cars that are far down the chain to be vanishingly small and leads to an...

Tennis is numbered among technically complex sports disciplines, where a variety of shots considerably affects the results obtained by professional players. According to the references worldwide, tennis players should master four areas: technical, tactical, physical and mental ones [1]. One of the most essential elements of technical training is backhand, which can be performed with one or two ...

One of the most important approaches in the scientific research concerning the increase of the positioning accuracy is the use of parallel structures. Parallel kinematic structures have a series of advantages that makes them adequate for the mini-robots construction: actuator positioning on the seating, miniaturization, stiffness, positioning precision and repeatability, actuators separation fr...

We present an algorithm for functional kinematic tolerance analysis of general planar mechanical systems with parametric tolerances. The algorithm performs worst-case analysis of systems of curved parts with contact changes, including open and closed kinematic chains. It computes quantitative variations and helps designers detect qualitative variations, such as blocking and under-cutting. The a...