A 6-DOF 4-4 parallel manipulator is presented. Its forward kinematics can be solved by a sequence of three trilaterations and, as a consequence, its singularities can be described in geometric terms as the degeneration of three tetrahedra. Moreover, it is shown how the proposed manipulator belongs to the family of flagged parallel manipulators. This identification is useful because the topology...

Mobile manipulators are of high interest to industry because of the increased flexibility and effectiveness they offer. The combination and coordination of the mobility provided by a mobile platform and of the manipulation capabilities provided by a robot arm leads to complex analytical problems for research. These problems can be studied very well on the KUKA youBot, a mobile manipulator desig...

The Stewart platform is a six-axis parallel robot manipulator with a force-to-weight ratio and positioning accuracy far exceeding that of a conventional serial-link arm. Its stiffness and accuracy approach that of a machine tool yet its workspace dexterity approaches that of a conventional manipulator. In this article, we study the dynamic equations of the Stewart platform manipulator. Our deri...

In this article, the authors investigate the fault tolerance of manipulators in their nominal configuration. In this work, fault tolerance is measured in terms of the worst case relative manipulability index. While this approach is applicable to both serial and parallel mechanisms, it is especially applicable to parallel mechanisms with a limited workspace. It is first shown that the relative m...

The LARMbot design is a mechanism-based structure that is inspired by the muscular-skeleton structure of the human anatomy considering the bones as per the serial chains and the muscular systems per the driving parallel architectures, [2]. In Figure 1 the main conceptual designs are shown as referring to the trunk structure as a combination of serial spine-like chain and a cable parallel manipu...

Abstract In this paper, a time - varying chattering free disturbance observer based position tracking control law of serial robotic manipulators is presented to track reference signal in finite time. The key idea employ positive-increasing function associated with the control/observer objectives improve performance. First, model an uncertain manipulator as case study proposed strategy. Then, fo...

The paper presents the compliance errors compensation technique for over-constrained parallel manipulators under external and internal loadings. This technique is based on the non-linear stiffness modeling which is able to take into account the influence of non-perfect geometry of serial chains caused by manufacturing errors. Within the developed technique, the deviation compensation reduces to...

This paper presents a five degrees-of-freedom (DoF) low inertia shoulder exoskeleton. This device is comprised of two novel technologies. The first is 3DoF spherical parallel manipulator (SPM), which was developed using a new method of parallel manipulator design. This method involves mechanically coupling certain DoF of each independently actuated linkage of the parallel manipulator in order t...