Optimal Force Distribution Based on Slack Rope Model in the Incompletely Constrained Cable-Driven Parallel Mechanism of FAST Telescope
This paper addressed the determination of the tension distribution in the slack steel wires of the incompletely constrained cable-driven parallel mechanism of FAST telescope. Slack rope hung with piecewise uniform mass is specially investigated. First, the general formulation based on the wrench matrix was derived. Then the analytical model of slack rope was built to give the quantized relation between direction and amplitude of tension vector. The wrench matrix is not only platform pose dependent but influenced by rope geometry. Finally, a performance index based on minimal tension variance is selected to optimize the tension distribution among steel wires. Levenberg-Marquardt method is applied to solve the quadratic program and a discrete-mesh plan is proposed for the whole focal surface. An example of computation is given to verify the effect of the resolution.
KeywordsSteel Wire Mobile Platform Base Frame Tension Distribution Focal Surface
The author would like to acknowledge the financial support of the National Natural Science Foundation (NNSF) under grant No. 10973023.
- 1.Nan, R.D.: Five-hundred-meter aperture spherical radio telescope (FAST). Sci. China Ser. G Phys. Mech. Astron. 49(2), 129–148 (2006).Google Scholar
- 2.Li, H., Zhu, W., Pan, G.: Equilibrium analysis of FAST rope-drive parallel manipulator based on rope force optimization. Eng. Mech. 28(4), 185–193 (2010) (in Chinese).Google Scholar
- 4.Bosscher, P., Ebert-Uphoff, I.: Wrench-based analysis of cable-driven robots. In: Proceedings of the 2004 IEEE International Conference on Robotics and Automation, pp. 4950–4955, New Orleans, LA, USA (2004).Google Scholar
- 6.Riechel, A.T., Ebert-Uphoff, I.: Force-feasible workspace analysis for underconstrained point-mass cable robots. In: Proceedings of the 2004 IEEE International Conference on Robotics and Automation, pp. 4956–4962, New Orleans, LA, USA (2004).Google Scholar
- 7.Li, H., Nan, R., Kärcher, H., et al.: Working space analysis and optimization of the main positioning system of FAST cabin suspension. In: Proceedings of SPIE, Astronomical Instrumentation, Ground-Based and Airborne Telescopes II, Marseille, vol. 70120T(1–11) (2008).Google Scholar