Thermal stabilization of inertial measurement units
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Solution Overview
Problem
Commercially available inertial measurement units (IMUs) at the lower end of the price spectrum suffer from low-frequency measurement instability due to thermal variations, leading to dominant sources of measurement errors, and existing mitigation techniques are either costly or introduce additional errors from external sensors.
Innovation Solution
A thermal stabilization system using a thermoelectric heating/cooling device based on the Peltier effect, coupled with thermal insulation and mechanical assembly, stabilizes IMU temperatures and reduces residual output errors through compensation algorithms, ensuring continuous, repeatable, and history-independent performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermal characterization in thermal chamber is performed, then measurement accuracy is improved, but device complexity and time consumption increase
Solution Approach 1:
The patent extracts the temperature sensor from the IMU and places it in direct thermal contact with the inertial sensors through thermal coupling mechanisms. This allows the temperature sensor to be positioned optimally for measuring sensor temperature without requiring complex thermal chamber equipment for characterization.
Solution Approach 2:
The system performs self-characterization by collecting temperature data during normal operation and using it to generate correction parameters. This eliminates the need for external thermal chamber equipment and reduces characterization complexity while maintaining measurement accuracy.
2Measurement precision
If thermal characterization is performed extensively, then measurement accuracy is improved, but time consumption increases
Solution Approach 1:
The system performs preliminary thermal characterization during manufacturing or initial setup, storing correction parameters in memory. These pre-determined parameters are then applied during normal operation, eliminating the need for extensive real-time characterization while maintaining accuracy.
Solution Approach 2:
The system uses temperature compensation parameters that are determined once during characterization and then applied continuously based on real-time temperature measurements. This approach captures the essential thermal behavior without requiring continuous extensive characterization.
3Measurement precision
If additional sensors are added for error correction, then measurement accuracy is improved, but reliability decreases due to additional error sources
Solution Approach 1:
The patent introduces a temperature sensor as an intermediary element that indirectly measures the thermal state of the inertial sensors. This temperature information is then used to compute correction parameters, providing accurate compensation without adding complex sensor fusion systems that could introduce additional errors.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively minimizes thermal stress and stabilizes IMU performance across varying temperatures, reducing measurement errors and improving accuracy without the need for expensive pre-characterization or additional sensors.
Implementation Method 1
A thermal stabilization system using a thermoelectric heating/cooling device based on the Peltier effect
Implementation Method 2
coupled with thermal insulation and mechanical assembly, stabilizes IMU temperatures
Data Source
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AI summary
A thermal stabilization system stabilizes inertia! measurement unit (IMU) performance by reducing or slowing operating variations over time of the internal temperature. More specifically, a thermoelectric heating/cooling device operates according to the Peltier effect, and uses thermal insulation and a mechanical assembly to thermally and mechanically couple the IMU to the thermoelectric device. The thermal stabilization system may minimize stress on the IMU and use a control system to stabilize internal IMU temperatures by judiciously and bidirectionaliy powering the thermoelectric heating/cooling device. The thermal stabilization system also may use compensation algorithms to reduce or counter residual IMU output errors from a variety of causes such as thermal gradients and imperfect colocation of the IMU temperature sensor with inertial sensors.