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.

https://journals.sagepub.com/doi/pdf/10.1177/1687814018774186

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

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.

/pdf/cable-driven-parallel-mechanisms-state-of-the-art-and-4342afa6ap.pdf

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

In this paper, redundancy resolution of a cable-driven parallel manipulator is performed through an analytic-iterative scheme. The redundancy resolution scheme is formulated as a convex optimization problem with inequality constraints that are imposed by manipulator structure and cable dynamics. The Karush-Kuhn-Tucker theorem is used to analyze the optimization problem and to draw an analytic-iterative solution for it. Subsequently, a tractable and iterative search algorithm is proposed to implement the redundancy resolution of such redundant manipulators. Furthermore, it is shown through simulations that the worst case and average elapsed time that is required to implement the proposed redundancy resolution scheme in a closed-loop implementation is considerably less than that of other numerical optimization methods.

An Analytic-Iterative Redundancy Resolution Scheme for Cable-Driven Redundant Parallel Manipulators

In this paper the dynamic analysis of a macro–micro parallel manipulator is studied in detail. The manipulator architecture is a simplified planar version adopted from the structure of the Large Ad...

Dynamic Analysis of a Macro–Micro Redundantly Actuated Parallel Manipulator

Gravitational lensing of epoch-of-reionization gas

The Large Adaptive Reflector (LAR) is a concept for a low-cost, large aperture, wideband, radio telescope, designed to operate over the wavelength range from 2 m to 1.4 cm. It consists of a 200-m diameter actuated-surface parabolic reflector with a focal length of 500 m, mounted flat on the ground. The feed is held in place by a tension-structure, consisting of three or more tethers tensioned by the lift of a large, helium-filled aerostat-a stiff structure that effectively resists wind forces. The telescope is steered by simultaneously changing the lengths of the tethers with winches (thus the position of the feed) and by modifying the shape of the reflector. At all times the reflector configuration is that of an offset parabolic antenna, with the capability to point anywhere in the sky above -15° Elevation Angle. At mid-range wavelengths, the feed is a multi-beam prime-focus phased array, about 5 m diameter; at meter wavelengths, it is a single-beam phased array of up to 10 m diameter. Simulations have shown that in operating wind conditions (10 m / s average speed with 2.5 m / s gusts), the position of the feed platform can be stabilized to within a few cm over time scales of -20 s. Research indicates that the telescope concept is feasible and that an order of magnitude improvement in cost per m 2 of collecting area over traditional designs of large parabolic antennas can be achieved.

The Large Adaptive reflector : A 200-m diameter, wideband, cm-m wave radio telescope

The Large Adaptive Reflector (LAR) is a concept for a low- cost, large aperture, wideband, radio telescope, designed to operate over the wavelength range from 2 m to 1.4 cm. It consists of a 200-m diameter actuated-surface parabolic reflector with a focal length of 500 m, mounted flat on the ground. The feed is held in place by a tension-structure, consisting of three or more tethers tensioned by the lift of a large, helium-filled aerostat -- a stiff structure that effectively resists wind forces. The telescope is steered by simultaneously changing the lengths of the tethers with winches (thus the position of the feed) and by modifying the shape of the reflector. At all times the reflector configuration is that of an offset parabolic antenna, with the capability to point anywhere in the sky above approximately 15 degree Elevation Angle. At mid-range wavelengths, the feed is a multi-beam prime-focus phased array, about 5 m diameter; at meter wavelengths, it is a single-beam phased array of up to 10 m diameter. Simulations have shown that in operating wind conditions (10 m/s average speed with 2.5 m/s gusts), the position of the feed platform can be stabilized to within a few cm over time scales of approximately 20 s. Research indicates that the telescope concept is feasible and that an order of magnitude improvement in cost per m2 of collecting area over traditional designs of large parabolic antennas can be achieved.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The large adaptive reflector: a 200-m diameter wideband centimeter- to meter-wave radio telescope

In recent years, the direct-liquid-cooled thin-disk lasers have become ahot research topic due to their advantages of extremely small volume to output power ratio and strong thermal management ability. A method of analyzing the wavefront aberration of the direct-liquid-cooled thin-disk laser is established in this paper. The influence of pumping light uniformity on the wavefront aberration is investigated by this method. The high order aberration distribution of the laser beam is calculated, when the uniformity is 92%, 80% and 70%,separately. With the decrease of beam uniformity, the higher order aberrationsincrease gradually, while the low order aberrations remain basically unchanged. Experimentally, the pumping beam distributions respectively with uniformity of 92% and 70% are designed with and without using the waveguide structure. The wavefront jitter and wavefront aberration distribution of the whole gain module are measured in these two cases. The pump power is kept at 5 kW. The higher order of optical path difference (OPDH) values of the whole gain module are measured to be 0.66 μm and 0.79 μm, respectively. The experimental results are in agreement with the theoretical analyses.

Xiaohui Deng

Papers

The Large Adaptive reflector : A 200-m diameter, wideband, cm-m wave radio telescope

The large adaptive reflector: a 200-m diameter wideband centimeter- to meter-wave radio telescope

Influence of pumping light uniformity on laser wavefront aberration in direct-liquid-cooled thin-disk laser