Vibration Control of Time-Varying Delay under Complex Excitation

Area of Science:

• Mechanical Engineering
• Control Systems Engineering
• Vibration Analysis

Background:

• Existing time-delay feedback vibration absorbers perform well under harmonic excitation but struggle with complex excitations.
• Fixed time-delay control parameters limit the effectiveness of dynamic vibration absorbers for non-harmonic disturbances.

Purpose of the Study:

• To develop an adaptive control strategy for time-delay dynamic vibration absorbers to handle complex excitations.
• To enhance the vibration attenuation performance of dynamic vibration absorbers by introducing time-varying delay parameters.
• To propose a harmonic equivalent method for complex excitations to enable real-time parameter adjustment.

Main Methods:

• A harmonic equivalent method was proposed to approximate complex excitations with equivalent harmonic ones.
• Time-delay parameters of the dynamic vibration absorber were adjusted in real-time based on the equivalent harmonic excitation's frequency.
• A two-degree-of-freedom vibration system with a delay dynamic vibration absorber was used for simulation and validation.

Main Results:

• The proposed time-varying delay dynamic vibration absorber achieved significant vibration reduction under complex excitations.
• Simulation results demonstrated a vibration reduction of approximately 30% in the main system compared to passive vibration absorbers.
• The adaptive control strategy effectively improved the performance of the delay dynamic vibration absorber.

Conclusions:

• The harmonic equivalent method and real-time parameter adjustment offer a new approach for enhancing vibration attenuation control.
• The developed time-varying delay dynamic vibration absorber shows superior performance over passive systems.
• This research provides a novel technical direction for designing active vehicle frame systems and other vibration control applications.