Wheel Force Transducer Stator Angle Correction
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Solution Overview
Problem
Wheel force transducers (WFT) systems face inaccuracies in measuring forces and moments on vehicle wheels due to variations in the stator angle of the encoder stator, especially when the wheels are steered, leading to incorrect representation of forces and moments in the vehicle coordinate system.
Innovation Solution
A stator angle correction device (SAC device) is introduced, which measures the stator angle and adjusts the wheel rotational position and speed signals to maintain accuracy, using a mounting bracket, rotary encoder, stator rod retainer, and controller to intercept and correct signals before coordinate transformation, ensuring the encoder stator remains substantially vertical during vehicle durability testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the encoder stator is fixed to the wheel without correction, then the measurement system is simple, but the measurement precision deteriorates due to stator angle variations during wheel steering
Solution Approach 1:
A stator angle correction device is introduced as an intermediary component between the wheel force transducer and the measurement system. This device includes a stator angle sensor that specifically measures the stator angle, and a correction mechanism that uses this measurement to compensate for angle-induced errors in force and moment measurements, thereby maintaining high measurement precision without requiring complete system redesign
Solution Approach 2:
The system dynamically changes the measurement parameters by introducing stator angle as an additional measured variable. The correction device adjusts the force and moment measurement values based on the measured stator angle parameter, applying correction factors that vary with the stator angle to maintain accuracy across different steering conditions
2Reliability
If the stator angle is not corrected, then the device complexity remains low, but the reliability of durability testing data deteriorates
Solution Approach 1:
The stator angle correction device implements a feedback mechanism where the stator angle sensor continuously monitors the actual stator angle during wheel steering, and this feedback information is used by the correction mechanism to adjust the force and moment measurements in real-time, ensuring reliable durability testing data even under dynamic steering conditions
Solution Approach 2:
The correction device performs preliminary correction of the measurement data by compensating for stator angle effects before the data is used for durability analysis. This preliminary action ensures that the raw measurement data is already corrected for angular deviations, improving reliability without requiring post-processing corrections
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 SAC device effectively corrects the inaccuracies in force and moment measurements by adjusting the wheel speed and rotational position signals based on the stator angle, providing accurate representation of forces and moments in the vehicle coordinate system, even when the wheels are steered, thus enhancing the reliability of vehicle durability testing data.
Implementation Method 1
the stator rod retainer is in mechanical communication with at least one bearing for rotation relative to a stationary portion of the rotary encoder
Data Source
AI summary
A stator angle is determined to correct a value measured by a wheel force transducer. A mounting bracket is rigidly attached to a vehicle and supports a housing within which a rotary encoder is mounted. A stator rod retainer is aligned with a rotational axis of the rotary encoder and has a through-bore extending perpendicular to the rotational axis. The stator rod retainer rotates relative to a stationary portion of the rotary encoder using at least one bearing, and the stator rod retainer supports a first end of a stator rod for substantially free movement through the through-bore. A controller determines, when the second end of the stator rod is fixedly attached to an encoder stator attached to a wheel, a stator angle of the stator rod used for adjusting at least one value associated with the wheel that is measured using the encoder stator.