Study and Application of the Equal-Area Smoothing Compensation Control Method on the UHPLC Pump

The paper has studied the motion process of the Ultra-High Performance Liquid Chromatography(UHPLC) pump. It has proposed an equal-area smoothing compensation control method, so as to solve the problem of jitter of the motor at the acceleration inflexion points. Meanwhile, it has done smoothing treatment to the original motion equation of the UHPLC pump, so as to ensure that the UHPLC pump transits stably on the acceleration inflexion points with high initial velocities, without jittering. Besides, smoothing compensation is made to the reduced displacement of the UHPLC pump after smoothing treatment, ensuring that displacement is made up on the single cycle end time point of the original motion equation, so that both the amount of the liquid taken in and total amount of the liquid discharged stay unchanged. The experiment proves that with the equal-area smoothing compensation control method, the problem of jitter of the motor at the acceleration inflexion points under high initial velocities is solved. As a result, flow precision of the UHPLC pump when outputting liquid has been improved from 0.119% to 0.055%. With this control method, flow precision of the UHPLC pump has been effectively improved, with strong instantaneity, high calculation precision and easily realized hardware, etc.