Analysis and Suppression of Nonlinear Error of Pendulous Integrating Gyroscopic Accelerometer at Instrument Level

Area of Science:

• Instrumentation
• Mechanical Engineering
• Aerospace Engineering

Background:

• Pendulous integrating gyroscopic accelerometers (PIGAs) are crucial for precise motion measurement.
• Bias and scale factor errors in PIGAs are well-understood, but nonlinear error remains a significant challenge.
• Improving PIGA accuracy necessitates addressing nonlinear error at the instrument level.

Purpose of the Study:

• To analyze the sources of nonlinear error in PIGAs.
• To develop and validate a method for suppressing PIGA nonlinear error.
• To enhance the overall measurement accuracy of PIGA devices.

Main Methods:

• Kinematics and dynamics analyses were employed to establish a PIGA error model.
• Nonlinear error components, including quadratic terms and cross-coupling effects, were analyzed.
• A suppression strategy targeting unequal inertia and inertia products was developed and experimentally tested.

Main Results:

• Nonlinear error was found to stem from unequal inertia, inertia products, lateral accelerations, and unequal stiffness.
• Unequal inertia and inertia products were identified as the primary drivers of nonlinear error.
• The proposed suppression method reduced the quadratic term coefficient by an order of magnitude.

Conclusions:

• Nonlinear error analysis provides a pathway for PIGA accuracy enhancement.
• Targeting unequal inertia and inertia products effectively suppresses PIGA nonlinear error.
• Experimental validation confirms the efficacy of the developed analysis and suppression method.