Autonomous Vehicle IMU Offset Compensation for Robust State Estimation

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Solution Overview

Problem

Autonomous vehicles face challenges in accurately determining their state due to deficiencies in inertial measurement units (IMUs), leading to divergent state estimations between map-relative and continuous pose filters, which can result in a stuck state until errors are resolved.

Innovation Solution

The autonomous vehicle control system identifies IMU data offsets by comparing data from multiple IMUs and sensor data, generating compensation transforms to correct for offsets within plausibility thresholds, thereby mitigating the effects of faulty or deviated IMUs and maintaining accurate state estimation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If IMU data is used for state determination, then localization operations can be performed, but IMU deficiencies cause data offsets leading to divergent state estimations between filters

Engineering Contradiction:
Improvestate estimation accuracyVSAvoidIMU data accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The system continuously monitors IMU data from multiple sensors and compares their outputs. When offsets are detected between IMUs or between IMU and sensor data, the system generates compensation transforms and applies them dynamically. This feedback mechanism ensures that state estimation accuracy is maintained despite individual IMU deficiencies, as the system constantly adjusts for detected errors in real-time operation

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically changes the parameters of IMU data by generating and applying compensation transforms. These transforms modify the offset parameters of deficient IMU data to align with reference data from healthy IMUs or sensor data. By changing the data parameters through mathematical transformation rather than hardware modification, the system corrects measurement precision issues while maintaining the overall localization function

Inventive Principle:
Principle #35Parameter changes

2Reliability

If multiple IMUs are used for redundancy, then reliability improves, but device complexity increases

Engineering Contradiction:
Improvesystem robustnessVSAvoidsensor suite complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system performs self-diagnosis by automatically detecting which IMUs are healthy and which have offsets. The control system autonomously identifies deficient IMUs by comparing data across multiple sensors and generates compensation transforms without external intervention. This self-service capability allows the system to maintain reliability through multiple IMUs while managing complexity through automated rather than manual calibration processes

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system segments the IMU data processing by treating each IMU independently, identifying individual sensor deficiencies rather than treating the sensor suite as a monolithic unit. By segmenting the analysis to individual IMU performance, the system can apply targeted compensation to specific deficient sensors while leaving healthy sensors unchanged, thereby managing complexity through modular rather than holistic processing

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If IMU offset compensation is applied dynamically, then state estimation accuracy is maintained, but processing complexity increases

Engineering Contradiction:
Improvestate determination accuracyVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs preliminary identification of IMU offsets by comparing data from multiple sensors before applying compensation. The control system pre-calculates compensation transforms based on initial comparisons between IMU data and sensor data, or between multiple IMUs. This preliminary action allows the system to prepare correction factors in advance, reducing the real-time processing complexity during actual state determination operations

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system introduces compensation transforms as an intermediary element between raw IMU data and final state estimation. Rather than directly processing potentially erroneous IMU data, the system applies transformation matrices as intermediaries that correct offsets before the data is used in localization operations. This intermediary layer simplifies the overall processing by isolating the complexity of offset correction in a dedicated transformation step

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If IMU data is continuously monitored for offsets, then reliability improves, but loss of time occurs during error resolution

Engineering Contradiction:
Improvelocalization accuracyVSAvoidtime to resolve stuck state
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system maintains continuous monitoring of IMU data and continuously applies compensation transforms rather than periodically checking for errors. The control system operates the offset compensation dynamically throughout localization operations, ensuring that state estimation accuracy is maintained without interruption. This continuous action prevents stuck states from occurring in the first place, eliminating the time loss that would result from error resolution after the fact

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentUS11536569B2IMU data offset compensation for an autonomous vehicle
Publication Date: 2022.12.27 AURORA OPERATIONS INC
  • US11536569B2 patent drawing
  • US11536569B2 patent drawing
  • US11536569B2 patent drawing

AI summary

A sensor data processing system for an autonomous vehicle receives inertial measurement unit (IMU) data from one or more IMUs of the autonomous vehicle. Based at least in part on the IMU data, the system identifies an IMU data offset from a deficient IMU of the one or more IMUs, and generates an offset compensation transform to compensate for the IMU data offset from the deficient IMU. The system dynamically executes the offset compensation transform on the IMU data from the deficient IMU to dynamically compensate for the IMU data offset.