GB924473A - A control system operating with optimum conditions for an automatic regulation of position - Google Patents

Abstract

924,473. Electric correspondence control systems. ZAVODY V.I. LENINA PLZEN NARODNI PODNIK. Aug. 10, 1959 [Aug. 9, 1958], No. 27202/59. Class 40 (1). In a closed loop servo system optimum response is obtained when the absolute value of the signal to the power part is constant and produces maximum power response, but for small deviations the input signals are proportional to the deviation. This is obtained by the use of non- linear elements in the feedback loop. As shown (Fig. 1) for maintaining two shafts 31, 32 in positional agreement, the shafts are electrically coupled by fine and coarse selsyn units 1, 2 respectively having a two to one gear ratio. The output from the fine selsyn unit 1 is fed via a limiter 14 and phase discriminator 15 to supply a constant voltage, whose sign depends on the sense of the positional error, to a coincidence circuit 19. The output from the coarse selsyn unit 2 is similarly fed through a reversing relay 22, and a phase discriminator 16 to coincidence circuit 19, which thus produces an output voltage only when its two inputs are of the same sign. This voltage is fed through a relay 21 and switch 22 to reverse the sign of the signal from selsyn 2 fed to phase discriminators 16, 23 each time the relay 21 is pulsed. The output from circuit 23 is fed through a non-linear member 24, together with the velocity difference signal obtained from tachogenerators 3, to a differencing member 25, so that their algebraic difference is fed to a coincidence circuit 28 together with the constant output voltage from discriminator 15, to produce an output when these voltages have the same sign, which is fed to relay 30 to add the constant output signal from tachogenerator 4 at member 11 with the signal from selsyn 2. The output from tachogenerators 4 is made constant over a wide range by feeding the field windings through a non- linear amplifier C from the output of selsyn 2. Thus amplifier 10 feeds amplidyne 9 with a signal which is proportional to the positional and speed difference between the shafts 31, 32 for small differences, and is otherwise of a constant magnitude having a polarity determined by a combination of the signs of the outputs from selsyns 1 and 2.