Angular or linear moving is the way which has been passed by working part of the machine during work. It’s always the basic coordinate of electromechanical system which is changed in time under demanded laws makes an ultimate goal of management of its movement. However, in the most practical cases of necessity of the direct control of this coordinate at work of electric drive does not arise, as batching of moving of working body is not required. Similar conditions are typical for electric drives of machines with cyclic working process, but among of the last machines such which working part for normal passing of technological process should at separate stages of work, or during each moment of time to occupy in space strictly fixed positions. Such machines and mechanisms is called to point-to-point; prominent feature of their electric drives is necessity of regulation of position.

        Unlike other coordinates regulation of position demands the obligatory discrete or continuous control of actual value of adjustable coordinate and purely parametrical cannot be carried out. At manual management the control of current position is carried out visually by the operator who influencing the task of speed of electric drives of the machine, provides moving its working body on a demanded trajectory or its installation in the fixed positions according to technological process. At the same time to the electric drive the requirement of position regulation is not demanded, but the electric drive should provide regulation of speed and possess the desired dynamic qualities facilitating conditions regulation of position by the operator. As a rule thus required automatic restriction of coordinate in extreme points of a working part of a trajectory. In the elementary cases it is carried out by switching-off of the electric drive and imposing of a mechanical brake on a signal device of order.

        Automatic control of position depending on concrete requirements can be carried out in three variants:

        1) exact positioning of the electric drive in the set points of a way on discrete signals of travelling gauges;

        2) continuous automatic control of position on a deviation for realization of the dosed out movings or in compliance with set program;

        3) continuous automatic control of position on a deviation at any way changing signal of the task (the watching electric drive).

        For maintenance of high accuracy and speed of positioning use the closed systems of automatic control of position on a deviation is used.

        Systems of automatic control of position are build by addition SAC of speed with system of automatic control of position. With this purpose used the closed system of regulation on deviation is used, for which construction are necessary the position sensor (or a angular deflection), a regulator of position and command device KU which produces a signal of the task of position φ^* . The regulator of position forms the task ω^* for the subordinate to SAC speeds. Thus, for regulation of position the three-planimetric structure containing an internal contour of regulation of a current of an anchor, an intermediate contour of regulation of speed and an external contour of regulation of position is used. Depending on kind of SAC of position RAMP can enter its structure, installing on output of PC, and selector of the positions, installing after OD.

        Distinguish following kinds SAC of position:

        •System without MP, without RAMP, with linear or parabolic PS;

        •System without MP, with RAMP, with linear or parabolic PC;

        •System with MP, without RAMP, only with linear PC.

        With the purpose of reduction of impacts in kinematic transfers in control systems of electric drives provide restriction not only speeds and accelerations, but also jerk. One of ways of restriction of jerk is installation on the input of system of automatic control of the setting device forming reference signals of the task for chaning basic coordinates of the electric drive. For position electric drives in such coordinates position φ, speed ω, acceleration and jerk ρ are.