【作者】 张帆；

【导师】 王子文； 李建功；

【作者基本信息】 河北理工大学 ， 机械制造及其自动化， 2009， 硕士

【摘要】 混合驱动机构是以常规电动机和伺服电动机作为驱动器,两种类型的输入运动通过一个二自由度机构合成后实现预期的输出运动,其中常规电动机为系统提供主要的动力,伺服电动机提供较小动力的同时主要起调节作用。它兼容了传统机械系统和全伺服驱动机械系统的优点。混合驱动七杆机构是在闭链五杆机构的基础上引入了二级杆组,使机构结构简单、柔性大,尺寸型和输入运动变化大,可以实现给定的轨迹或运动,具有较高的实际应用价值。将混合驱动七杆机构运用在压力机上,使得它既有传统机械式压力机的大功率、运行平稳等优点,又具有可控性、可调性,能够提供多组输出运动规律。因此,混合驱动压力机,不用改变机构几何参数,通过控制伺服电机运动规律,就能够较为方便地调节压力机滑块的位移和速度,以满足不同材料加工工艺的要求。分析了机械式压力机滑块运动的典型规律,对混合驱动压力机的可行性进行了分析,选择了适于拉伸工艺的混合驱动七杆压力机的机构构型。运用回路矢量法对混合驱动七杆机构进行了逆运动学、正运动学分析,分别求出了混合驱动七杆机构中各构件的位移、速度和加速度的解析表达式。建立了混合驱动七杆机构的优化设计模型,并将优化分为两步:第一步,假定伺服电机角速度与常规电机相同的条件下,优化设计出机构的尺寸参数;第二步,在第一步优化结果的基础上,使机构的尺寸参数不变,优化设计伺服电机输入运动规律。并用5次多项式对伺服电机的运动规律进行了优化设计,最后求得满足加工工艺要求的伺服电机角速度曲线。结论表明通过改变伺服电机的运动规律,不仅能调节滑块的速度,而且可实现不同的位移和速度曲线,即可实现适应不同工况的滑块的多组输出运动规律,从而实现了混合驱动压力机滑块运动规律的柔性输出。更多还原

【Abstract】 Hybrid-driven mechanism is driven by constant speed motor and servomotor. Inputs from a uniform constant speed motor and a programmable motion servomotor are summed in two degrees of freedom at the output of the linkage. With this machine, the constant speed motor supplies the main torque and power, while the servomotor, which supplies a little part of torque and power, adjusts the output motion. This kind of machine system not only has advantages of classical mechanical system, but also is controllable and has great flexibility. Hybrid-driven seven-bar mechanism is formed by introducing a two linkage bar to five-bar mechanism. This is a new mechanism of simple structure with big flexibility which can generate given path or movement. It has high practical value.This kind of press not only had advantages of classical press system, but also was controllable and had great flexibility with applying hybrid-driven seven-bar mechanism to press, it could provide for programmable motion outputs. Therefore, without changing the geometric parameters of the system, only through adjusting the trajectory of servomotor displacement, the press could meet different material processing requirements.The typical kinetic rules of the mechanical presses were analyzed. Then the feasibility of hybrid-driven seven-bar mechanical presses was discussed. The type of the hybrid-driven mechanical press suitable for deep drawing was selected. The forward and inverse kinematics analysis of the hybrid-driven seven-bar mechanism was made by loop vector method, and the displacement, velocity and acceleration resolution expressions of each part were worked out.In order to realize the flexible output of the slider, the optimum design of the hybrid-driven seven-bar mechanism was carried out through two major processes. The first process was to optimize the geometric parameters of the mechanism, on the assumption that the servomotor rotates at a constant angular velocity equal to the constant velocity motor. The second process was to optimize the displacement trajectory of the servomotor based on the results of the first process while keeping the geometric parameter unchangeable. The input displacement of the servomotor was separately optimized by using polynomial curve. The results pointed out that by adjusting the trajectory of servomotor displacement, the velocity of slider was not only changed, but also achieved different curve of displacement and velocity. It could provide for programmable motion outputs, the flexible output of slider was gained.更多还原