Control Algorithm Design of a Force-Balance Accelerometer

Area of Science:

• Instrumentation and Measurement
• Control Systems Engineering
• Mechanical Engineering

Background:

• Force-balanced accelerometers (FBAs) utilize closed-loop control, with performance critically dependent on the control algorithm.
• Conventional control strategies often limit FBA accuracy and frequency bandwidth by focusing solely on response minimization.

Purpose of the Study:

• To design a novel control algorithm for force-balanced accelerometers that accounts for time delays.
• To enhance the measurement accuracy and operational frequency range of FBAs.

Main Methods:

• Model predictive control (MPC) was employed to design the control algorithm for the FBA.
• A variable augmentation method was proposed to transform the control problem into measurement error minimization.
• Discretization methods were used to address time delays within the closed-loop system.

Main Results:

• The proposed MPC-based control effectively manages time delays in the FBA's closed loop, up to 10 times the control period.
• Accurate acceleration measurements were achieved across a frequency range exceeding 500 Hz.
• The vibration response of the FBA's sensitive element was maintained at the micron level, ensuring a wide measurement range.

Conclusions:

• The developed MPC-based control algorithm significantly improves FBA performance, overcoming limitations of conventional methods.
• The strategy enables accurate, high-frequency acceleration measurements with a broad dynamic range.
• This advancement is crucial for applications requiring precise inertial sensing.