第2章直流伺服电动机.ppt

控制电机;2.1 直流伺服电动机工作原理;掌握直流伺服电动机工作原理;2.1 直流伺服电动机的工作原理和结构;SZ系列直流伺服电动机;GZ系列直流伺服电动机;二、直流伺服电动机的工作原理; 当线圈转动180o ,导体cd处于N极下，电流由c到d，S极下导体电流由b到a ，导体受力仍然是逆时针方向。;2.2 直流伺服电动机的控制方法;2 直流电动机的调速;0;3 改变直流电动机转向的方法;4 使用中必须注意的问题;二、直流伺服电动机的控制方法;直流伺服电动机稳定运行时的转速为：;2.3 直流伺服电动机的特性分析;Uj;令 n = 0 ，得：;3. 放大器对电动机机械特性的影响;二、直流伺服电动机的调节特性;n; 3 变负载时的调节特性;4 直流伺服电动机低速运转的不稳定性; 2）低速时，控制电压数值小，电刷和换向器之间的接触压降不稳定性的影响将增大，故导致电磁转矩不稳定性增大。;2.4 直流伺服电动机的工作状态; 电动机以转速n1驱动天线跟踪飞机，此时电机的电枢电压为Ua1 ，反电势为Ea1，电枢电流为Ia1，转速为n1。;Uj;Ea1; 这种运行方式是利用电动机原来积蓄的动能来发电，以产生电磁转矩进行制动的，所以叫能耗制动。;n;2.5 直流伺服电动机的过渡过程;Uj; 对已制成的电机而言，?j 机电时间常数、?d 电磁时间常数、n0 都是常数，根据直流电动机在动态下的方程建立转速对时间、电枢电流对时间的微分方程，并求解得：;电机的过渡过程曲线：;2.6 直流力矩电动机;2.7 低惯量直流伺服电动机;2）灵敏度高。; 它具有转动惯量低、启动转矩大、反应快、启动 灵敏度高、转速平稳、低速运行均匀、换向性能 好等优点。其输出功率为几十瓦到10KW，机电常 数为5~10ms。主要用于要求快速动作、功率较大的系统如数控机床和雷达天线驱动等方面。; In-line Bottle Filling A application is shown in Fig. 1. In this application multiple filling heads line up with bottles as they move along a continuous line. Each of the filling heads must match up with a bottle and track the bottle while it is moving. Product is dispensed as the nozzles move with the bottles. In this application 10 nozzles are mounted on a carriage that is driven by a ball-screw mechanism. The ball-screw mechanism is also called a lead screw. When the motor turns the shaft of the ball screw, the carriage will move horizontally along the length of the ball-screw shaft. This movement will be smooth so that each of the nozzles can dispense product into the bottles with little spillage.; The servo drive system utilizes a positioning drive controller with software that allows the position and velocity to be tracked as the conveyor line moves the bottles. A master encoder tracks the bottles as they move along the conveyor line. An auger feed system is also used just prior to the point where the bottles enter the filling station. The auger causes a specific amount of space to be set between each