A Robust Control Algorithm of a Descent Vehicle Angular Motion in the Earth’s Atmosphere

A new approach to synthesize a robust controller for the angular motion of the Earth lander by decomposition method of output modal control is proposed. A universal analytical solution for the problem of stabilizing the angular position of the lander is obtained. A comparative analysis of the presented algorithm with the currently used onboard algorithm for descent control of the manned spacecraft Soyuz is carried out. The advantages of the new algorithm relative to the existing algorithm are presented, both in terms of stabilization accuracy and the consumption of the working fluid of the control motors.

Dynamic modal control of unmanned vehicle movement in open pit mining

The purpose of this study is to present a number of aspects in the modern concept of computer-aided dynamic modal control of unmanned quarry vehicles in open pit mining. In particular, the software and hardware module that is a part of the “Smart Quarry” global structure deals with the conditions of matching a form of specific current trajectories (their deviation to the left or right of the nominal axial trajectory) to information “trajectory” chirp signals. The study employs the methods of wavelet transforms to convert one-dimensional signals that generate unmanned vehicle current trajectories into the time-frequency distributions of Cohen’s class. The formation of unmanned vehicle current trajectories under their deviation to the left / right from the nominal axial trajectory on straight and curved routes is considered schematically. It is noted that the tracking of unmanned current trajectories on quarry routes is carried out taking into account the nature of trajectory signals. The difference between the introduced dynamic modal control of the unmanned vehicle and the static one is formulated. Some fragments displaying 1D-signals in a wavelet medium are introduced into the autonomous and external control subsystems. The computer-aided control system uses such elements of the wavelet transforms technique as Gabor wavelet functions, the wavelet matching pursuit algorithm, and Cohen’s class time-frequency distributions. The research results in formulating the criteria for forming the unmanned vehicle current trajectories by the control system in the form of its reactions to sporadic disturbances caused by the occurrence of static or dynamic obstacles on a route. The algorithm of dynamic modal control of current trajectories has been developed. The concept of forward and reverse transient processes of signals of unmanned vehicle trajectory deviation has been introduced. The estimation procedure of modal controller parameters has been described. The algorithm has been developed for modal controller matrix recalculation, which has the form of the chain of sequentially implemented matrix procedures. It should be noted in conclusion that a computer-aided system for modal control of current trajectory deviation has been developed on the basis of the performed research. It enables to implement the functions of controlling the dynamics of technological and safe movement of unmanned vehicles along the quarry routes in a conflict environment of open pit mining.

OPTIMIZATION IN SPEED OF THE RELAY-MODAL CONTROL SYSTEM OF THE SERVO DRIVE BASED ON THE STUDY OF THE MATHEMATICAL MODEL

Positional control systems are characterized by the limitation of intermediate coordinates in transients. Such restrictions are implemented by a system with cascading controllers. The N-i switching method provides optimization of the speed of such control systems. In this paper, we study the three-loop system of subordinate regulation. The parameters of the relay-modal controllers were varied based on a change in the calculated amplitude of the control action without changing its real value. The parametric synthesis of such a system is based on optimal trajectories in terms of speed. The study of the control system at various settings revealed a different degree of deviation of transitional trajectories from the calculated one. This effect is due to the replacement of optimal regulator settings with modal ones in order to give the system a margin of stability. The obtained families of transient characteristics make it possible to construct empirical dependences of the duration of regulation on the relative value of the calculated amplitude of the control action. Such dependencies have pronounced extremes, which makes it possible to tune the system to a near optimal speed by preventing the regulators from entering the sliding mode prematurely. The performed simulation of the positional system with extremal settings confirms the effectiveness of the proposed methodology for the correction of dynamic characteristics. The results of the study open up the prospects of the practical implementation of relay-modal control algorithms for cascading systems, the synthesis of which is based on the N-i switching method.