GB1289134A - - Google Patents

Abstract

1289134 Automatic control systems HARTMANN & BRAUN A G 25 Nov 1969 [3 Dec 1968] 57541/69 Heading G3R The invention is concerned with preventing excessive overshoot in the response to a step change in the reference signal in a closed loop control system which could occur when the system is designed for optimum response to a disturbance. The closed loop control system receives a reference input signal w and is subject to a disturbance signal z, and provides a controlled output signal x. The signal w is applied directly to a junction 2 to be compared with signal x and form a deviation signal xw. The signal w is also applied to an attenuator 9 to provide signal kw which is added to the output signal V2y of an amplifier 8. A decaying function generator 7 receives the resultant signal and provides feedback signal xr which is added to signal xw to form an effective reference input to amplifier 4. The amplified signal y with any disturbance signal z forms the input to the controlled system 6. The signal y is also applied to amplifier 8. When the signal w is changed abruptly, for example when starting, the output signal x oscillates about the effective reference input to the amplifier 4 but not beyond the value defined by the signal w. An element having a proportional plus derivative action may be connected between the summation points 2 and 3, Fig.4 (not shown). In another arrangement, this element is located on the input side of the point 2, Fig.6 (not shown). It may be replaced by a delay member in the feedback circuit, Fig.7 (not shown).