Abstract

The Five-hundred-meter Aperture Spherical radio Telescope is the world’s largest single-dish radio telescope and is located in the southwest of China. The cable-driven parallel robot and A-B rotator of the feed support system in Five-hundred-meter Aperture Spherical radio Telescope are designed to realize the theoretical position and attitude of the receiver. The feed support system is a pose-redundant and rigid–flexible coupling system; thus, the method of pose distribution between the A-B rotator and the cable-driven parallel robot impacts on the cable tension distribution and stiffness of the feed support system, which are crucial to the feed support system stability. The main purpose of this study is to examine the pose optimal distribution method for the feed support system. First, a mechanical model of the feed support system, which considers the time-varying barycenter of the feed cabin and the back-illuminated strategy of the receiver, is established. Then, a pose distribution method that ensures the position and attitude accuracy of the receiver is proposed for the feed support system. Considering the performance indices of the variance of cable tensions and the stiffness of the cable-driven parallel robot, an optimization of the rotation angles of the A-B rotator with multiple objectives is implemented using a genetic algorithm. Finally, simulations are conducted to demonstrate the effectiveness of the proposed method compared with others. Results show that the proposed approach not only ensures the attitude accuracy of the receiver but also maintains the lower variance of cable tensions and higher stiffness of the feed support system.

Highlights

  • The feed support system (FSS) is composed of a six-cable-driven parallel robot (CDPR) and a feed cabin.[5,6,7]

  • The CDPR and A-B rotator are designed to realize the theoretical pose of the receiver

  • The back-illuminated strategy of the receiver and the dimensionless stiffness of the FSS were derived in detail

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Summary

Introduction

The FSS is composed of a six-cable-driven parallel robot (CDPR) and a feed cabin.[5,6,7] the feed cabin contains three mechanisms: a star frame, A-B rotator, and rigid Stewart manipulator. When the feed cabin is located on the center point of the focal surface, and the FSS is on the initial pose, the three axes of each coordinate system are, respectively, parallel to each other and with the same pointing direction. Let fTig (oi-xizi) be the ith cable coordinate system, which is attached to the ith anchor node with the z-axis in the direction opposite to the force of gravity and with the x-axis horizontally pointing to the ith support tower.

C R AB ðAB R B ðB RPPKC RABðABRBBK lli þ
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V þ þ jjT Ai jjA jjT Bi jj
Declaration of conflicting interests
Findings
Conclusions and future work
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