Synergetic control of aircrafts actuators

G.E.Veselov

Taganrog Technological Institute of Southern Federal University

Russia

Obtained results were approved by Be-200 simulating device using numerical math model of Be-200 amphibian aircraft. We present control design procedure of synergetic control laws design for aircrafts actuators that are built on induction motor.  The vector control designed uses nonlinear mathematical model of induction motor that is written in rotating coordinate system with respect to rotor flux linkage. The proposed approach increases efficiency and precision of aircraft control system.

The application of actuators that use induction motors (IM) in aircraft control systems is a promising approach. IM is a reliable and efficient motor with the most simple design. IM are widely used in all electromechanical systems (EMS) where a wide range of frequency and angle of rotation are required. However, attempts to utilize these excellent features of IM in controlled EMS face fundamental scientific obstacles. The problem is that, from the control perspective, IM is an electromechanical plant with the most sophisticated dynamics. The challenging properties of the IM that complicate the control design are high-nonlinearity, and high order of a dynamic model describing behavior of IM in different operating modes. In order to make efficient control for IM, we ought to control several interrelated coordinates such as frequency of rotation, angular position, torque, magnetic flux, current etc. However, among numerous control strategies developed for IM, those that treat IM as one control channel system are most popular. For example, principle of constant V/Hz control relates amplitude of stator voltage to frequency of feeding voltage. In addition, these control strategies are usually designed using simplified linear models that are unable to adequately reflect real physics of the processes. Moreover, control design methods “compensate” or ignore nonlinearity or multi-connectivity, separate control channels, etc. Of course, such methods put significant limitations on achievable qualitative characteristics of IM such as region of stability, range of regulation, and stiffness of mechanical characteristic. As a result, all of the above limits capabilities of IM.

Application of synergetic control theory developed in early works removes the limitations on the dynamic order of the systems as well as those on nonlinear interactions within the system and creates a foundation for more efficient vector controls. In particular, use of the synergetic approach to analytical design of vector control for IM is a break-through that allows the designer to solve the complex problem of control design for IM more efficiently.

The paper shows that application of the synergetic approach allowed us to design a new dynamic nonlinear regulator. This regulator ensures asymptotic stability of the steering actuator, robustness against change of loading coefficient, and invariance to external disturbances. Such behavior of the closed-loop system is based on an asymptotic transition from one invariant manifold to another. During this transition the dimensionality of invariant manifolds becomes smaller. As a result, in case of inconsistency between the parameters of the system and the parameters of the model, it is only necessary that closed-loop system comes into the region of attraction of the invariant manifold where the required state is maintained.