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.

Modal decoupling control for a double gimbal magnetically suspended control moment gyroscope based on modal controller and feedback linearization method

To effectively reject the gyroscopic effects and moving-gimbal effects of the double gimbal magnetically suspended control moment gyroscope (DGMSCMG) and to avoid high control effort, this paper proposes a novel control method based on modal decoupling strategy. Modal controller is employed to realize the modal separation of the translation and rotation modes of the magnetically suspended rotor (MSR). Then the dynamic coupling among the two rotation modes of the MSR system and the two rotational motions of the gimbal servo systems have been decoupled by using differential geometry theory. Dynamic compensation filters have been designed to improve the decoupling performance and the system stability without large control resource. Compared with the existing channel decoupling method, the presented one can not only realize the separate control of stiffness and damping of the MSR but also simplify the control system design significantly. The simulation results verify the effectiveness and superiority of the proposed method.

A Mechanical Approach to the Design of Independent Modal Space Control for Vibration Suppression

Many systems have, by their nature, a small damping and therefore they are potentially subjected to dangerous vibration phenomena. The aim of active vibration control is to contain this phenomenon, improve the dynamic performance of the system, and increase its fatigue strength. A way to reach this goal is to increase the system damping, preferably without changing its natural frequencies and vibration modes. In the past decades this has been achieved by developing the well-known independent modal space control (IMSC) technique. The paper describes a new approach to the synthesis of a modal controller to suppress vibrations in structures. It turns from the traditional formulation of the problem and it demonstrates how the performance of the controller can be evaluated through the analysis of the modal damping matrix of the controlled system. The ability to easily manage this information allows us to synthesize an efficient modal controller. Furthermore, it enables us to easily evaluate the stability of the control, the effects of spillover, and the consequent effectiveness in reducing vibration. Theoretical aspects are supported by experimental applications on a large flexible system.