Destabilization of velocity feedback controllers with stroke limited inertial actuators

Area of Science:

• Mechanical Engineering
• Control Systems Engineering
• Nonlinear Dynamics

Background:

• Active structural vibration reduction commonly employs inertial actuators with velocity feedback control.
• Stroke saturation in actuators can lead to unexpected system instability.
• Understanding actuator limitations is crucial for reliable control system design.

Discussion:

• A simple nonlinear, time-domain model of an inertial actuator on a single-degree-of-freedom system is presented.
• The model demonstrates how velocity feedback enhances damping at low amplitudes.
• Analysis reveals the onset of instability and limit cycle oscillations at higher amplitudes due to actuator saturation.

Key Insights:

• Inertial actuators with velocity feedback controllers are prone to instability when stroke-limited.
• The system transitions from effective damping to unstable limit cycle oscillations.
• The frequency of these limit cycle oscillations is predictable.

Outlook:

• Further research can explore advanced control strategies to mitigate instability caused by actuator saturation.
• Investigating different actuator types and control architectures may yield more robust vibration reduction systems.
• Experimental validation of the presented model is recommended for real-world applications.