Analysis and active control of low frequency booming noise in car

For Lightweight body,sound radiation and sound insulation performance have negative effects on interior noise by the deterioration of local stiffness and modality.So the research on the active control of vibration and noise for car body panels is useful for engineering.Analysis and active control of booming noise in car is researched by using a new active damping vibration reduction technology named smart constrained layer damping(SCLD).According to the vibration characters of body roof,an optimal placement of actuators is distributed.Based on dSPACE hardware in loop environment,an adaptive active control system is designed.Selecting vibration signals of engine mounting point as the reference input of adaptive controller,an active control experiment of booming noise for mini-car is carried out.Experimental results show that,when the engine speed is at 3700 RPM and4250RPM,the interior booming noise decreases 4.2dB(A),and 3.5dB(A) separately.It proposes new methods and techniques for intelligent control of car body NVH in the future.

Application of linear active disturbance rejection control for photoelectric tracking system

Dynamic characteristics and tracking precision are studied in the photoelectric tracking system and a linear active disturbance rejection control( LADRC) scheme is proposed for position loop. A current and speed controller is designed by a transfer function model,which is obtained by adaptive differential evolution. Model error,friction and nonlinear factor existing in position loop are treated as ‘disturbance',which is estimated and compensated by generalized proportional integral( GPI)observer. Comparative results are provided to demonstrate the remarkable performance of the proposed method. It turns out that the proposed scheme is successful and has superior features,such as quick dynamic response,low overshoot and high tracking precision. Furthermore,with the proposed method,friction is suppressed effectively.

Optimization of the number and the positions of error sensors in adaptive active sound control

In recent years, researches on the attenuation theory of active sound control and the technique of adaptive active sound control have becn made independently. By optimizing the number and the positions of error sensors, a relation between them is found in this paper. The method and the formulae for optimization are given. The factors affecting the attenuation effects are discussed. All theoretical results are verilied by experiments and the attenuation effects are satisfied.

Synchronization of Modified Chua＇s Circuit with x｜x｜ Function

This paper considers the chaos synchronization of the modified Chua 's circuit with x|x| function. We firstly show that a couple of the modified Chua systems with different parameters and initial conditions can be synchronized using active control when the values of parameters both in drive system and response system are known aforehand.Furthermore, based on Lyapunov stability theory we propose an adaptive active control approach to make the states of two identical Chua systems with unknown constant parameters asymptotically synchronized. Moreover the designed controller is independent of those unknown parameters. Numerical simulations are given to validate the proposed synchronization approach.