Abstract
In many applications, digital valves driven from stepping motors are often characterized by quantitative errors and in some cases, slow response. A new means of direct digital control is introduced for a spool valve actuated by a stepper motor. With this control strategy, both excellent speed of response and accuracy are simultaneously sustained for the valve. By way of illustration, the characteristics of a digital spool valve are theoretically and experimentally investigated. This paper also deals with the design of the controller and some concepts concerning the digital control of a valve, such as initialization, false protection, etc. An example is given to demonstrate the effectiveness of this digital control approach for a practical electro-hydraulic control system.
