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Control Systems - Dynamic Synthesis - Introduction


Control of a power hydraulic drive at positioning executive mechanisms, especially for manipulators and robotic-technical systems, requires the special algorithms providing necessary characteristics of movement, including dispersal and braking. As the hydraulic drive with volumetric and throttle regulation can be used as a power servo drive of manipulators and robots, we’ll consider both essentially possible ways of regulation of a hydraulic drive.

Control of a power hydraulic drive of volumetric regulation for the opened system without correcting links and feedback on phase coordinates (at a stage of so-called "rough" control) is maybe constructed by two various methods:

- a method of the multiple periods of natural fluctuations when the period of control is divided on the following intervals: dispersal, statics and braking; and time of control of hydraulic system gets out minimal, but multiple to the period of natural fluctuations, proceeding from their condition total absence on a site established movements (statics);

- a method of the movement law planning at which the certain boundary conditions (generally are specified – conditions in central points of a trajectory), on which factors of an approximating polynomial (generally – a spline [1, 2]), defining according to mathematical model of considered hydraulic system function of control – relative working volume of the variable displacement pump are defined.

The same method it is possible to construct control of a hydraulic drive of throttle regulation, but here function of control will be the variable area of through passage section throttling arrangements. The special case of this problem is considered in the section "Dynamic synthesis of hydraulic devices".
As examples below problems of control by a power hydraulic drive of volumetric regulation with the closed circulation of the stream, illustrating possibilities of offered algorithms of control, both from the point of view of accuracy of positioning, and by way of performance of the restrictions, concerning dynamics of transients are considered.
For the decision of the given problem and the analysis of the synthesized algorithms of control the method of computer modeling by means of the program of the computer-aided dynamic analysis of hydraulic systems HYDRA (see the section "Hydraulic Systems. Dynamic Analysis") the basic modes of movement of a hydraulic drive (dispersal – statics – braking) has been used at various algorithms of control.

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