EPS Torque Sensor PWM Processing for Initial Voltage Offset Errors
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Solution Overview
Problem
Inaccurate initial voltages detected by torque sensors in EPS systems due to electromagnetic interference lead to significant errors in PWM signals, affecting the accuracy of the EPS system.
Innovation Solution
Employing symmetrically arranged first and second torque sensors to calculate an average initial voltage, determining duty cycles of PWM signals using this average initial voltage and a conversion coefficient, thereby equalizing and averaging offsets between the sensors to improve signal accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single torque sensor is used to detect voltage signal, then the device complexity is low, but the measurement precision of the voltage signal is inaccurate due to electromagnetic interference affecting the initial voltage
Solution Approach 1:
The single torque sensor is segmented into two torque sensors arranged symmetrically on opposite sides of the steering shaft. Each sensor detects voltage signals independently, and the initial voltages are averaged to obtain a more accurate reference value, thereby improving measurement precision while managing device complexity through systematic division
Solution Approach 2:
A second torque sensor is introduced as a copy of the first torque sensor, positioned symmetrically. Both sensors detect voltage signals and initial voltages, which are then averaged to compensate for electromagnetic interference effects, improving the accuracy of the voltage signal without requiring a completely new sensing mechanism
2Measurement precision
If the initial voltage from a single torque sensor is used for PWM conversion, then the conversion process is simple, but the PWM signal accuracy is low due to considerable errors from inaccurate initial voltage
Solution Approach 1:
The voltage signals and initial voltages from both torque sensors are merged through averaging to produce a single, more accurate initial voltage value. This combined initial voltage is then used for PWM conversion, improving PWM signal accuracy by reducing the impact of electromagnetic interference on any single sensor
Solution Approach 2:
The initial voltages from both torque sensors are detected and averaged in advance before the PWM conversion process. This preliminary averaging action provides a more accurate reference value for the subsequent PWM conversion, thereby improving the accuracy of the final PWM signal while maintaining a straightforward processing workflow
Data Source
AI summary
Provided is a torque signal processing method, an EPS sensor, and a storage medium. The method includes: determining a duty cycle of a first PWM signal according to a first voltage collected by a first torque sensor, an average initial voltage, and a conversion coefficient; and determining a duty cycle of a second PWM signal according to a second voltage collected by a second torque sensor, the average initial voltage, and the conversion coefficient. The average initial voltage is calculated according to a first and second initial voltages respectively collected by the first and second torque sensors when torque is 0, and the duty cycle of the first PWM signal and the duty cycle of the second PWM signal are determined according to the first voltage collected by the first torque sensor, the second voltage collected by the second torque sensor, the average initial voltage, and the conversion coefficient.