基于差动行星轮系的重载软启动系统的动力学分析

Dynamics analysis on heavy loaded soft startup system based on differential planet gear train

差动行星轮系能够对运动进行合成和分解。采用差动行星轮系的运动合成功能,并利用磁粉制动器控制差动轮系的运动,可以控制重载启动的过程并实现软启动。对启动过程进行分析,并建立了启动过程的动力学模型。在已知磁粉制动器的输出力矩函数时,可将连续系统的微分方程形式转化为差分形式的状态方程进行求解仿真;若给定负载的速度曲线,则可通过数值方法求得磁粉制动器力矩函数。通过对某软启动装置进行仿真,得出在负载保持不变的情况下,当磁粉制动器的输出力矩均匀增加时,负载启动过程并不平稳;要使负载启动平稳,需要在力矩增大到一定程度之后逐渐减小,给出了能使负载平稳启动的力矩施加函数。

The differential planet gear train could carry out composition and resolution on movements. By adopting the movement composition function of differential planet gear train and utilizing the magnetic powder brake to control the move ment of differential gear train, thus the process of heavyqoaded startup can be controlled and the soft startup can be achieved. This paper carried out analysis on the startup course, and established the dynamics model of startup process. While the output moment function of magnetic powder brake is known, let the differential equation form of continuous system be translated into the differential formed state equation for carrying out simulative solution. If the velocity curves of load are given, the moment function of magnetic powder brake can be obtained by means of numerical value method. By way of carrying through a simulation on certain soft startup device, a result was obtained that while the load is keeping a constant and the output moment of magnetic powder brake is increasing evenly, but the process of loaded startup is not smooth. Should the loaded startup is wanted to be an even and smooth one, it is necessary to reduce the moment gradually after the moment has been increased to a certain extent. The moment exertion function that could let the loaded startup be a smooth was presented in this paper.