Steering Angle Determination Using Yaw Rate and Wheel Speed Sensors
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Solution Overview
Problem
Existing vehicle operator assistance systems that use relative position sensors face challenges in determining the steering angle relative to the neutral position quickly after vehicle start-up, leading to delayed system effectiveness and potential shutdowns due to steering sensor failures.
Innovation Solution
A system utilizing a yaw rate sensor and wheel speed sensors to determine steering angles, allowing the controller to select and modulate torque distribution to the rear wheels, thereby approximating the steering angle and maintaining system functionality despite potential sensor failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a relative position sensor is used to determine steering angle, then the system cost and complexity are reduced, but the system cannot determine the neutral position quickly after vehicle start-up
Solution Approach 1:
The patent introduces an intermediary calculation method that uses readily available sensor data (wheel speed sensors and yaw rate sensor) to estimate the steering angle relative to neutral position. This intermediary approach bypasses the need for complex neutral position detection algorithms while providing sufficiently accurate data for operator assistance systems to function immediately after vehicle start-up.
Solution Approach 2:
The patent replaces the mechanical/physical neutral position detection mechanism with a computational approach. Instead of using complex sensors or mechanical reference systems to physically determine neutral position, the system uses mathematical calculations based on wheel speed and yaw rate data to compute the steering angle relative to neutral, enabling immediate system operation.
2Measurement precision
If a neutral position determination algorithm is implemented, then the steering angle can be determined, but the algorithm takes finite time to complete and renders the system ineffective prior to completion
Solution Approach 1:
The patent performs preliminary calculations using data from wheel speed sensors and yaw rate sensor that are already being collected for other vehicle functions. By preparing and processing this data in advance through a calculation method that estimates steering angle from these readily available sensors, the system eliminates the need for time-consuming neutral position calibration algorithms, enabling immediate system operation upon vehicle start-up.
Solution Approach 2:
The patent makes existing sensors (wheel speed sensors and yaw rate sensor) serve multiple functions. These sensors, originally intended for basic vehicle dynamics monitoring, are also used to calculate steering angle relative to neutral position. This multi-functional use eliminates the need for dedicated neutral position detection hardware or time-consuming calibration procedures.
3Reliability
If the steering sensor fails or data is interrupted, then the operator assistance system shuts down, but continuous operation is needed
Solution Approach 1:
The patent prepares alternative calculation methods using data from wheel speed sensors and yaw rate sensor in advance. These alternative data sources are continuously monitored and ready to be used if the primary steering angle sensor fails. This preparatory approach ensures that the operator assistance system can maintain continuous operation without interruption by switching to the alternative calculation method when sensor failure or data interruption occurs.
Data Source
AI summary
A system for determining an angular position of a pair of steerable wheels of a vehicle having a plurality of wheels can include a yaw rate sensor, a pair of wheel speed sensors and a controller. The yaw rate sensor can be configured to output data representative of an angular velocity of the vehicle about a vertical axis of the vehicle. Each of the pair of wheel speed sensors can be configured to output data representative of a rotational velocity of a respective one of the plurality of wheels. The controller can be in electrical communication with each of the pair of wheel speed sensors and the yaw rate sensor. The controller can be configured to determine a first steering angle based on data received from the yaw rate sensor, to determine a second steering angle based on data received from the plurality of wheel speed sensors, and to select one of the first steering angle and the second steering angle for use in manipulating various vehicle parameters, including torque vectoring parameters, among other parameters.