Inertial Sensor Offset Correction via Angular Rate Mediation
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Solution Overview
Problem
Existing vehicle stability control systems face inaccuracies due to non-coincident mounting of accelerometers with vehicle spatial axes, leading to erroneous sensor data, and require a method to compensate for off-axis sensor mounting locations while utilizing existing rotational and acceleration sensors effectively.
Innovation Solution
A method involving an accelerometer mounted at a location different from the vehicle center of gravity, with a control module communicating with angular rate sensors to calculate correction factors based on moment arms and angular velocities, modifying accelerometer output signals to align with vehicle spatial axes, and incorporating additional sensor inputs for dynamic correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If accelerometers are mounted at locations different from the vehicle center of gravity, then the flexibility of sensor mounting is improved, but measurement precision deteriorates due to off-axis mounting errors
Solution Approach 1:
The patent introduces angular rate sensors as intermediary devices that measure rotational velocity about vehicle spatial axes. These sensors serve as mediators between the off-axis accelerometer and the vehicle's center of gravity coordinate system, enabling the system to compensate for mounting offsets by calculating correction factors based on measured angular rates and known moment arms.
Solution Approach 2:
The patent implements a feedback mechanism where angular rate sensor outputs are continuously fed into the correction algorithm. The system dynamically calculates correction factors based on real-time angular velocity measurements and applies these corrections to accelerometer outputs, creating a closed-loop system that compensates for off-axis mounting errors during vehicle operation.
2Measurement precision
If rotational velocity sensors and accelerometers are mounted with axes aligned to vehicle spatial axes, then measurement precision is improved, but device complexity increases due to stringent mounting requirements
Solution Approach 1:
The patent changes the parameter of sensor mounting location from requiring precise alignment with vehicle spatial axes to allowing flexible off-axis mounting. By introducing correction algorithms that use angular rate measurements and moment arm calculations, the system transforms the problem from one requiring precise mechanical alignment to one that tolerates various mounting configurations through computational compensation.
3Measurement precision
If accelerometers are accurately mounted in known relationship to vehicle spatial axes, then measurement precision is improved, but ease of operation deteriorates due to difficult mounting procedures
Solution Approach 1:
The patent uses angular rate sensors as intermediary measurement devices that capture rotational velocity information. This intermediary approach allows the system to indirectly compensate for accelerometer mounting errors without requiring direct precision alignment, simplifying the installation process while maintaining measurement accuracy through computational methods.
Data Source
AI summary
A method for compensating inertial sensor measurement outputs for mounting locations that are not coincident, nor orthogonal, with the vehicle center of gravity. The method further utilizes vehicle angular rate measurements, data, or estimates to determine the discrete acceleration components of the composite inertial sensor measurement output.