| 摘要 |
<p>VALVE CONTROL SYSTEM A system for the control of a fluid flow control valve (14) which controls the supply of fluid to an actuator (12) to control the movement of a component such as a tractor implement hitch (10,13) in response to a selected operating parameter such as hitch position or draft force. The system enables the desired value of the selected parameter to be set (S) and this desired value is compared (P,D)with the actual sensed value of the parameter to provide a parameter error signal (E) . A start-up control function (SUC) is provided to improve the initial speed of response of the system. The start-up control function is arranged on each detection of a parameter error signal to apply a start-up signal to the valve to initiate movement of the component and, if no movement results, to increase the start-up signal until movement of the component is detested (20,25) whereupon the increase in the start-up signal is stopped and the magnitude of the signal applied to the valve is dependent on the parameter error signal so as to tend to reduce the error signal to zero.</p> |
