Servo ED

Servo ED is closed automatic system, with the help of which executional mechanism with specified accuracy develops the motion of operation mechanism correspondently to set signal, as such that can be changed by arbitrary way.

Servo ED (SED) is used at automatic control of changing of various physical values in metallurgical, metal-cutting, excavator ED, in manipulators and so on. Power of SED is from some Watts up to tens of kilowatts.

In general case SED (figure 7.17) consists of giver, servo (receiving) device of amplifier and executional motor. Giver with receiving device (receiver) create a device which is called difference meter. Named elements of SED are interconnected so that changing of position of giveracts through the receiver and amplifier on motor, which develops set on the giver displacement. SED operates only due to difference, which occurs between giver and executional motor (mechanism). Process of SED operation is permanent automatic elimination of occurring difference.

Figure 7.17 – Structural scheme of SED.

By principle of operation control systems SED are divided into 2 groups:

- SED with relay (discontinuous) control;

- SED with continuous control.

SED with relay control is specific by that the voltage is applied to executional motor only in that case when difference angle reaches a specified value. In process of difference angle increasing to this value the motor is motionless. Angular speed and angular acceleration of motor after its switching on do not depend on difference angle, but are defined by parameters of ED (,, ). In SED with discontinuous control relay-contactor apparatuses or contactless devices with relay characteristic are used.

The characteristic feature of SED with continuous control is continuous control of executional motor, that depends on current angle of difference.

Correspondently to requirements to SED of relatively high accuracy of difference developing in static and dynamic regimes, operation stability, high-response and so on, SED is designed with various feedbacks, that provide control in function of difference angle and its differential, in function of difference angle and integral of this angle and so on.

Дата добавления: 2014-01-05