Coordination method in design of forming operations of hierarchical solid objects
The application of the coordination technology in the design of forming operations is regarded. The coordination design method was developed by using hierarchical systems construction and dynamic systems (by M. Mesarovich and Y. Takahara), numeric positional systems, and aed formal model (by S. Novikava). Solid objects being designed and their forming operations were presented in hierarchical form taking under consideration the objectpsilas structure, its external presentation as the unit in environment system and the environment system construction. All the design and control actions are executed by coordinator on its selection, learning and self-organization layers by one of coordination strategy. Theoretical basis description and computer realization of the proposed coordination technology for the exemplary forming tasks solving are also presented in the paper.
Maximum torque per ampere control of induction motor drive without mechanical sensor
In this paper, the direct rotor flux field orientation control of speed sensorless induction motor (IM) is presented. In proposed control scheme, the maximum torque per ampere (MTPA) control strategy is achieved using a so-called fast flux search method. Based on this method, for a given load torque and rotor speed, the magnitude of rotor reference flux is adjusted step by step until the effective value (RMS) of stator current becomes minimized finally. In addition, using the IM fifth order model in the stationary reference frame, a nonlinear rotor flux observer is developed which is capable of motor resistances and rotor speed simultaneously estimation. Moreover, a useful method is introduced for DC offset compensation which is a major problem of AC drives especially at low speeds. Simulation and experimental results are presented to confirm the effectiveness of the proposed method.
L1 Adaptive Controller for Attitude Control of Multirotors
In this work we show an application of L1 Adaptive control theory for attitude control of UAVs. We implement the flight control system on a multirotor to show robustness and precise attitude tracking in the presence of modeling uncertainties and environmental disturbances. We choose backstepping control architecture, since the kinematics and dynamics of multirotors in most cases can be written in strict feedback form. We further exploit the fact that the kinematics of the plant, while free of uncertainties, is nonlinear, which makes it highly suitable for dynamic inversion control at each level of backstepping. On the other hand, plant dynamics is uncertain and is affected by environmental disturbances such as wind gusts, unmodeled dynamics etc. Therefore, we consider 3 variants of the control architecture. The first method uses backstepping to determine the moment demand and augments it with the L1 adaptive controller to account for uncertainties and provide robustness with guaranteed transient performance. The second architecture apply the concept of L1 adaptive backstepping to the same problem; and the third architecture uses L1 backstepping for quaternion representation of the system dynamics, which helps to avoid the singularities associated with Euler angles.