| 摘要 |
An analog/digital control system for a tractor. In the system is performed the measurement of a factor, or factors, dominating the work performance of the tractor's lifting attachment or of the actuator of a work implement. In this way is formed the actual value signal of the control system and its set-point signal (a), and the signal (e) stating their difference, on the basis of the latter being governed an analog/digital control unit, which governs the control means of the actuator, such as a solenoid valve (16,22,23). The control deviation signal in analog form is transformed into digital form by the sampling in order to establish a so-called dead range in the time dimension. The digital signal is processed in comparator members (9,12), in which have been set the limit values (Ty,Ta) defining the dead range. When in the sampling procedure the pulse amplitudes fall once or several times outside the dead range (Ty-Ta), such influence is exerted on the sampling means that transition is made to continuous following of the control deviation and in this manner the requisite control measures are carried out. When a value (e2) derived from the control deviation falls in the dead range (Ty-Ta), transition is made back to the sampling procedure. |
