双电动机驱动弛张筛及其伺服控制系统

Double motor driven flip-flow screen and its servo control system

普通弛张筛中双筛框的振动相位会根据筛板上来料量的变化而变化,很难实现固定筛框和浮动筛框理想的180°相位差,导致筛分效率不能保证。针对上述问题,建立了双电动机驱动弛张筛力学模型及振动方程,得到弛张筛固定筛框和浮动筛框之间的振幅和相位关系,并分析得出:双激振电动机转速同步且偏心块的相位差为170°时,双筛框的振动相位差能达到180°。提出了一种基于双电动机驱动的弛张筛伺服控制系统,采用了基于交叉耦合的转速同步控制方法和改进的基于点动Bang-Bang的相位补偿控制算法。仿真结果表明:该系统在启动阶段跟随速度快,调整时间短,超调量小,转速同步情况比较理想;转速及相位补偿速度快,转速波动幅度为70r/min左右,偏心块相位差波动幅度控制在5°以内,具有较强的抗干扰性。

Vibration phase of two screen frames in ordinary flip-flow screen varies in accordance with the change of incoming materials, and phase difference between fixed screen frame and floating screen frame is difficult to maintain at ideal 180 degrees, which leads to low screening efficiency. In view of the above problems, mechanical model and vibration equation of double motor driven flip-flow screen were established, relationship of amplitude and phase between fixed and floating screen frames were obtained, and it was concluded that when speed of double excitation motor was synchronized and phase difference of eccentric block is 170°, vibration phase difference of double screen frames can achieve 180°. Servo control system of double motor driven flip-flow screen was proposed, and cross-coupling-based speed synchronization control method and improved Bang-Bang-based phase compensation control algorithm were used. The simulation results show that the system follows quickly in startup phase with short adjustment time and small overshoot, ideal speed synchronization;rotation speed and phase compensation speed are fast, absolute value of speed fluctuation amplitude is about 70 r/min, and eccentric block phase difference fluctuation amplitude is controlled within 5°, which verifies the system has strong anti-interference performance.