Motor Position Sensor Offset Detection in Electric Brake Boosters
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Solution Overview
Problem
Accurately detecting the offset of a motor position sensor in an electric booster braking system after the motor is coupled is challenging, as existing methods require separation of the motor, which is inconvenient and affects system stability.
Innovation Solution
An apparatus and method that generate command voltage vectors to align the motor's rotor phases, allowing for offset detection without motor separation, using a command voltage vector generation unit and offset detection unit to calculate phase differences and determine necessary corrections based on system state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the motor position sensor offset is detected after the motor is coupled to the electric booster braking system, then the system integration is maintained, but the offset detection accuracy is compromised due to piston movement limitations
Solution Approach 1:
The system performs preliminary actions by commanding the piston to move to extreme positions (fully forward or fully backward) before conducting offset detection. This preliminary positioning ensures that the piston is at a known reference state, enabling accurate offset measurement even within the constrained system-integrated environment.
Solution Approach 2:
The system changes operational parameters by applying specific voltage vectors that command the piston to extreme positions, then transitions to detection mode. By dynamically adjusting the piston position through controlled movement commands and utilizing the relationship between commanded position and actual sensor feedback, the system achieves accurate offset detection without requiring motor separation.
2Measurement precision
If the motor is separated to detect the offset of the motor position sensor, then the offset detection accuracy is improved, but the system complexity and operation convenience are reduced
Solution Approach 1:
The system performs self-service by using its own actuation capability to position the piston and conduct offset detection while integrated. The control unit commands voltage vectors that move the piston to extreme positions, then measures the sensor feedback to calculate offset, all without external intervention or motor separation.
Solution Approach 2:
The motor-position-sensor-integrated assembly performs multiple functions: it acts as both the actuator for piston movement and the sensor for offset detection. The same motor and sensor combination used for normal braking operation is utilized for self-diagnosis, eliminating the need for separate testing equipment or motor separation procedures.
3Stability of the object's composition
If the piston movement is constrained after motor coupling, then the system stability is maintained, but the offset detection capability is degraded
Solution Approach 1:
The system dynamically adjusts piston position through controlled voltage vector application, moving the piston to extreme positions temporarily for detection purposes. This dynamic positioning capability allows the system to overcome static constraints and achieve the full range of motion needed for accurate offset measurement while maintaining overall system stability.
Solution Approach 2:
The system uses feedback from the motor position sensor to detect the actual piston position and calculate the offset. By comparing the commanded position (known from applied voltage vectors) with the actual position (measured by the sensor), the system determines the offset value, transforming the detection difficulty into a solvable measurement problem through feedback analysis.
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
Enables accurate detection and correction of motor position sensor offsets within the electric booster braking system, improving operational stability and eliminating the need for inconvenient motor separation, thus enhancing overall system performance.
Implementation Method 1
generate a command voltage vector having a predefined command phase and command voltage and apply the command voltage vector to the motor such that the piston moves in a direction determined based on the current position of the piston
Implementation Method 2
detect the offset of the motor position sensor based on a phase difference between a command phase of the command voltage vector and an actually measured phase obtained by actually measuring, by the motor position sensor, a phase formed by rotors of the motor aligned as the command voltage vector is applied
Data Source
AI summary
An apparatus and a method to detect an offset of a motor position sensor. The apparatus includes a command voltage vector generation unit configured to, in a state in which a motor has been coupled to an electric booster braking system, generate a command voltage vector having a predefined command phase and command voltage and apply the command voltage vector to the motor such that a piston moves in a direction determined based on the current position of the piston, and an offset detection unit configured to detect the offset of the motor position sensor based on a phase difference between a command phase of the command voltage vector and an actually measured phase obtained by actually measuring, by the motor position sensor, a phase formed by rotors of the motor that are aligned as the command voltage vector is applied from the command voltage vector generation unit to the motor.