Investigating the dynamic characteristics of the hydrostatic bearing spindle system with active piezoelectric restrictors

Studies show that active control technology can improve system performance and meet the increasing industrial demand in diverse applications. In the present study, the dynamic characteristics of the bearing-spindle system based on active piezoelectric (PZT) restrictors, including the amplitude-frequency and phase-frequency characteristics are analyzed theoretically and experimentally. In the analysis, the influence of the pipeline model on the system characteristics is studied. Then the feasibility and effectiveness of the active control method are verified through experiments. It is demonstrated that the theoretical and experimental results are consistent. The present study is expected to provide a guideline for further investigations on the structural optimization and control law design for active hydrostatic oil-film bearing spindle systems.

Circuit Implementation of the Jerk Chaotic System in Integer and Fractional Order Domains

This paper investigate a 3D chaotic oscillator with entire and fractional derivatives. We design an electrical circuit which modelling an autonomous oscillator, able to implement one of the classical Jerk equations. We analyze the dynamics of nonlinear system analytically and numerically. The results show that the fractional model can exhibit chaotic dynamics where it should be impossible if one would consider the classical model. This work also explore the synchronization of initial conditions of two identical Jerk systems through the active control method.

An active control method for reducing sonic boom of supersonic aircraft

Sonic boom reduction has been an urgent need to develop the future supersonic transport, because of the heavy damages of the noise pollution. This paper provides an active control method for the supersonic aircraft to reduce the sonic boom, wherein a suction slot near the leading edge and an injection slot near the trailing edge on the airfoil suction surface are opened, and the mass flow sucked in near the leading edge is equal to the mass flow injected near the trailing edge. The diamond and 566 airfoils are adopted as the baseline airfoil to verify the capability of the active control method, and the effects of the suction and injection location, the mass flow rate and the attack angle on the ground boom signature, the maximum overpressure, the drag coefficients and the ratio of lift to drag are studied in detail. The results show that the proposed active control method can significantly reduce the sonic boom, and the reduction of the sonic boom intensity is more sensitive to the injection near the trailing edge than the suction near the leading edge. Applying this active control method to the diamond (NACA0008) airfoil, when the mass flow rate is 6.5 kg/s(7.5 kg/s), the value of maximum positive overpressure is decreased by 12.87%(12.85%), the value of maximum negative overpressure is decreased by 33.83%(56.77%) and the drag coefficient is decreased by 9.50%(10.96%). It can be seen that the method proposed in this paper has great benefits in the reduction of sonic boom and provides a useful reference for designing a new generation of lower sonic boom supersonic aircraft.

Controlling Chaos in a Newly Designed Chaotic Hamiltonian System Based on Hénon-Heiles Model using Active Controlled Hybrid Projective Synchronization

In this paper, a systematic approach is designed for investigating the hybrid projective synchronization (HPS) in identical chaotic Hamiltonian systems based on Hénon-Heiles Model by using active control method (ACM). Initially, an active control law is described to achieve asymptotic stability of state vectors of given system using Lyapunov stability theory (LST). Additionally, numerical simulations utilizing MATLAB toolbox are presented to validate the efficiency and effectiveness of the designed approach. Furthermore, the proposed strategy has numerous applications in encryption and secure communication.

Comparison of Times of Synchronization of Chaotic Burke-Shaw Attractor with Active Control and Integer and Optimum Fractional-Order Pecaro Carroll Method

Many studies have been introduced in the literature showing that two identical chaotic systems can be synchronized with different initial conditions. Secure data communication applications have also been made using synchronization methods. In the study, synchronization times of two popular synchronization methods are compared, which is an important issue for communication. Among the synchronization methods, active control, integer, and fractional-order Pecaro Carroll (P-C) method was used to synchronize the Burke-Shaw chaotic attractor. The experimental results showed that the P-C method with optimum fractional-order is synchronized in 2.35 times shorter time than the active control method. This shows that the P-C method using fractional-order creates less delay in synchronization and is more convenient to use in secure communication applications.

A new approach on the modelling, chaos control and synchronization of a fractional biological oscillator

This research aims to discuss and control the chaotic behaviour of an autonomous fractional biological oscillator. Indeed, the concept of fractional calculus is used to include memory in the modelling formulation. In addition, we take into account a new auxiliary parameter in order to keep away from dimensional mismatching. Further, we explore the chaotic attractors of the considered model through its corresponding phase-portraits. Additionally, the stability and equilibrium point of the system are studied and investigated. Next, we design a feedback control scheme for the purpose of chaos control and stabilization. Afterwards, we introduce an efficient active control method to achieve synchronization between two chaotic fractional biological oscillators. The efficiency of the proposed stabilizing and synchronizing controllers is verified via theoretical analysis as well as simulations and numerical experiments.