高速凸轮NURBS廓线改进人工鱼群多目标动力学优化

摘要

为改善高速凸轮机构动力学性能,首先采用非均匀有理B样条(NURBS)重构凸轮廓线,建立高速凸轮单自由度弹性动力学模型,进行高速凸轮机构多目标动力学优化设计.然后利用改进人工鱼群算法求解该模型,获取系统Pareto最优解从而得到优化后的NURBS廓线.最后,分析和比较高速凸轮机构在NURBS和修正正弦两种廓线下的动力学响应.结果表明:改进人工鱼群算法可以有效解决多目标优化问题,优化后NURBS廓线运动学特性与修正正弦廓线相差不大,在一定程度上降低了高速凸轮机构的残余振动幅值,提高了高速凸轮机构的定位精度和动力性能,减少了振动和冲击的噪声.%To improve dynamic characteristics of high-speed cam mechanisms,Non-uniform rational B-Spline (NURBS) was used to fit a modified-sine curve.Based on the SDOF elastic dynamic theory,a multi-objective dynamic optimization model for NURBS profile was designed here.The multi-objective dynamic model was optimized to search a Pareto optimal solution with an improved artificial fish swarm algorithm,the optimized NURBS profile was acquired.Finally,the dynamic responses of a high-speed cam mechanism under NURBS profile and modified sine profile were analyzed and compared.The results showed that the improved artificial fish swarm algorithm can effectively solve the multi-objective optimization problem; the optimized NURBS profile keeps the modified sine profile's fine kinematic characteristics,and the residual vibration is reduced; the high-speed cam mechanism designed by using this method has advantages of stable transmission and lower noise.