Brian Moore

Bio: Brian Moore is an academic researcher from Austrian Academy of Sciences. The author has contributed to research in topics: Kinematics & Wrench. The author has an hindex of 6, co-authored 11 publications receiving 202 citations. Previous affiliations of Brian Moore include Laval University.

On the Ability of a Cable-Driven Robot to Generate a Prescribed Set of Wrenches

Abstract: This paper presents a new geometry-based method to determine if a cable-driven robot operating in a d-degree-of-freedom workspace (2≤d≤6) with n≥d cables can generate a given set of wrenches in a given pose, considering acceptable minimum and maximum tensions in the cables. To this end, the fundamental nature of the available wrench set is studied. The latter concept, defined here, is closely related to similar sets introduced by Ebert-Uphoff and co-workers (2004, “Force-Feasible Workspace Analysis for Underconstrained, Point-Mass Cable Robots,” IEEE Trans. Rob. Autom., 5, pp. 4956–4962; 2007, “Workspace Optimization of a Very Large Cable-Driven Parallel Mechanism for a Radiotelescope Application,” Proceedings of the ASME IDETC/CIE Mechanics and Robotics Conference, Las Vegas, NV). It is shown that the available wrench set can be represented mathematically by a zonotope, a special class of convex polytopes. Using the properties of zonotopes, two methods to construct the available wrench set are discussed. From the representation of the available wrench set, computationally efficient and noniterative tests are presented to verify if this set includes the task wrench set, the set of wrenches needed for a given task.

Interval-Analysis-Based Determination of the Wrench-Feasible Workspace of Parallel Cable-Driven Robots

Abstract: This paper deals with the wrench-feasible workspace (WFW) of n-degree-of-freedom parallel robots driven by n or more than n cables. The WFW is the set of mobile platform poses for which the cables can balance any wrench of a given set of wrenches, such that the tension in each cable remains within a prescribed range. Requirements of nonnegative cable tensions, as well as maximum admissible tensions, are thus satisfied. The determination of the WFW is an important issue since its size and shape are highly dependent on the geometry of the robot and on the ranges of allowed cable tensions. The approach proposed in this paper is mainly based on interval analysis. Two sufficient conditions are presented, namely, a sufficient condition for a box of poses to be fully inside the WFW and a sufficient condition for a box of poses to be fully outside the WFW. These sufficient conditions are relevant since they can be tested, with the means to test them being discussed in the paper. Used within usual branch-and-prune algorithms, these tests enable WFW determinations in which full-dimensional sets of poses (volumes) are found to lie within or, on the contrary, to lie outside the WFW. This provides a useful alternative to a basic discretization, the latter consisting of testing a discrete (zero-dimensional) finite set of poses. In order to improve the efficiency of the computations, a means to mitigate the undesirable effects of the so-called wrapping effect is introduced. The paper also illustrates how the proposed approach is capable of dealing with small uncertainties on the geometric design parameters of a parallel cable-driven robot.

A review on topological architecture and design methods of cable-driven mechanism:

Abstract: Research on the cable-driven mechanism has greatly developed with the booming of the robots in the past 30 years, and a range of corresponding theoretical studies have been published on them. The large-scale robot or manipulator with the complex cable-driven mechanism can be reconfigured. However, more theoretical studies are required on their topological architecture design and optimization to achieve this. Therefore, the applied cable-driven architectures and the corresponding theoretical studies are reviewed and summarized here. The parallel, serial, and differential architecture are illustrated, as well as their theories and methods, such as the workspace analysis based on the Jacobian matrix, particle swarm optimization and genetic algorithm, and kinematic design based on the graph theory are described. The features of the architecture and the theory studies are concluded. It is hoped that this study will help with design of future studies.

Stability Analysis of Underconstrained Cable-Driven Parallel Robots

Abstract: This paper studies cable-driven parallel robots with less than six cables, in crane configuration. A geometrico-static model is provided, and the stability of static equilibrium is assessed within the framework of a constrained optimization problem. The method relies on ordinary linear-algebra routines, and it may be very simply applied to the most general architectures. Several examples are provided, concerning robots with a number of cables that range from 2 to 4.

On the determination of the force distribution in overconstrained cable-driven parallel mechanisms

Abstract: This paper addresses the determination of the force distribution in the cables of a redundantly actuated cable-driven parallel mechanism. First, the static model of cable-driven parallel mechanisms is derived based on the wrench matrix. Then, four performance indices are considered in order to solve the underdetermined problem associated with the distribution of the forces. A simple numerical example is then developed in order to provide insight into the problem, which leads to a geometric interpretation of the results. Based on the presented results, it is proposed to use a p-norm (e.g. a 4-norm) to optimize the distribution of the forces in a cable-driven parallel mechanism in order to minimize the largest deviations from the median forces (or other target values) while maintaining continuity in the solution. A non-iterative polynomial formulation is then proposed for the 4-norm. It is also pointed out that this formulation leads to a unique real solution.

Cable-driven parallel mechanisms: state of the art and perspectives

Abstract: This paper presents a review of the state of the art in the area of cable-driven parallel mechanisms. The basic kinematic architecture of cable-driven parallel mechanisms is first recalled and the associated kinematic and static model is briefly exposed. Fundamental problems are formulated, including the definition of the wrench matrix, the wrench-closure workspace and the wrench-feasible workspace. Advances that have been made in the determination of such workspaces are reported. The dynamics and control of cable-driven parallel mechanisms are then considered, first for fully constrained cable-driven parallel mechanisms and secondly for cable-suspended parallel mechanisms. Calibration and identification issues are also addressed and various alternative architectures of cable-driven parallel mechanisms are reported. Finally, applications are considered and open issues are mentioned.