Vehicle Speed Estimation Using Attitude-Corrected IMU Signals
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Solution Overview
Problem
Conventional vehicle speed estimation methods using inertial measurement units (IMUs) are prone to noise accumulation, leading to divergent sensor values and inaccurate speed estimation, which poses a risk in developing sustainable transportation systems.
Innovation Solution
A vehicle speed estimation device that utilizes an attitude angle estimator, angular speed corrector, vector term calculator, and vehicle speed estimator to calculate vehicle speed using corrected angular speed, gravity acceleration vector, and acceleration model values, incorporating tire model and wheel speeds to stabilize the estimation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If acceleration and angular speed detected by sensor in the IMU are used as they are, then the vehicle speed estimation can be performed, but noise or the like in a sensor value will accumulate and the value will diverge
Solution Approach 1:
The patent implements feedback by using the estimated attitude angle to correct the angular speed detection values. The corrected angular speed is then used in subsequent attitude angle estimation, creating a closed-loop system that prevents noise accumulation and divergence while maintaining estimation accuracy.
Solution Approach 2:
The patent introduces an intermediary correction mechanism where the estimated attitude angle serves as a mediator to adjust the raw angular speed detection values. This intermediary step filters out noise and prevents direct accumulation of sensor errors in the vehicle speed estimation process.
2Reliability
If a correction mechanism using estimated attitude angle is introduced, then noise accumulation is suppressed, but the device complexity increases
Solution Approach 1:
The patent makes the attitude angle estimator serve multiple functions: it not only estimates the vehicle's attitude angle for stabilization control but also provides correction values for the angular speed sensor. This multi-functionality reduces the need for separate correction mechanisms, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent merges the attitude angle estimation function with the angular speed correction function into a unified estimation process. By combining these functions, the system avoids the complexity of separate correction devices while achieving noise suppression and improved reliability.
Data Source
AI summary
A vehicle speed estimation device of the embodiment includes an attitude angle estimator configured to estimate an attitude angle using an acceleration detected by an acceleration sensor and an angular speed detected by an angular speed sensor, which are attached to a vehicle, an angular speed corrector configured to correct the angular speed using the estimated attitude angle estimation value to calculate a corrected angular speed, a vector term calculator configured to calculate a gravity acceleration vector using the estimated attitude angle estimation value, a model configured to calculate an acceleration model value on the basis of a tire model using a steering angle of the vehicle and wheel speeds of wheels of the vehicle, and a vehicle speed estimator configured to estimate a vehicle speed of the vehicle using the corrected angular speed, the gravity acceleration vector, and the acceleration model value.