Numerical method of forward position solution for 6-3 Stewart platform based on mechanism simplification
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摘要: 针对提高Stewart平台运动学位置正解速度的问题,分析了传统基于速度雅可比的数值迭代方法,并对6-3 Stewart平台结构提出了一种基于机构简化的位置正解数值方法.将6-3 Stewart平台等效为虚拟3-RPS并联机构,通过牛顿-拉夫逊方法对其进行位置正解,并将结果解算为实际机构上平台位姿.设计了一套液压6-3 Stewart平台实验系统,并通过实验证明,与传统方法相比,该方法能减少近50%的迭代次数和约85%的解算时间.该方法概念清晰,机构等效计算简单,对3-RPS并联机构的位置正解计算量明显减少,在目前主流工控机处理器上可满足控制周期0.1 ms实时控制的位置解算需求.Abstract: To increase the speed of forward position solution for Stewart platform, the classical iterative method based on speed Jacobian was analyzed, and the new method for 6-3 Stewart platform was proposed. 6-3 Stewart platform was simplified as virtual 3-RPS parallel mechanism and its forward position solution was obtained by Newton-Raphson method. The result was solved back to the pose of actual platform. Experimental results on self-designed hydraulic 6-3 Stewart platform system present that, compared with classical method, the new one reduced nearly 50% of iterations and about 85% of time cost for solution. The concept of the new method is clear, mechanism simplification is easy implementing, and the computational cost of forward position solution for simplified 3-RPS parallel mechanism is significantly decreased. The new method is capable for forward position solution in a real-time control with 0.1 ms control cycle.
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