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在ADAMS中建立传动机构的铰接点,连接各点建立八连杆机构的虚拟样机模型。参数化各铰接点的横纵坐标作为设计变量,比较各设计变量对工作行程内滑块速度标准差的影响,选择敏感度较大的设计变量作为优化变量。基于曲柄存在条件建立约束关系,以工作行程内滑块速度标准差的最小值作为优化目标。采用广义简约梯度法,引入松弛变量将不等式约束转化成等式约束,用非基变量表示基变量,将目标函数改写成关于非基变量的表达式,进行迭代计算得到优化结果。适当调整优化后设计变量的值,得到最终的结果。与优化前机构对比,工作行程内,最大速度由590 mm·s~(-1)降至425 mm·s~(-1),速度标准偏差由175 mm·s~(-1)降至120 mm·s~(-1)。
In the ADAMS establishment of transmission hinge point, connect the points to establish eight-bar linkage virtual prototype model. The horizontal and vertical coordinates of each hinge point are parameterized as design variables. The influence of each design variable on the standard deviation of the slider speed in the working stroke is compared, and the design variable with greater sensitivity is selected as the optimization variable. Constraints are established based on the existence of crank, and the minimum value of standard deviation of slider velocity in working stroke is taken as the optimization target. The generalized minimal gradient method is introduced. The relaxation variable is introduced to transform the inequality constraint into the equality constraint. The non-radical variable is used to denote the base variable. The objective function is rewritten into the expression about non-radical variables, and the optimization result is obtained through iterative calculation. Properly adjust the value of the optimized design variables to get the final result. Compared with the pre-optimization mechanism, the maximum speed decreased from 590 mm · s ~ (-1) to 425 mm · s ~ (-1) within the working schedule and the standard deviation of speed decreased from 175 mm · s -1 to 120 mm · s ~ (-1).