Non-Contact Position Shift Sensing for Torque Error Detection
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Solution Overview
Problem
Existing methods for determining torque and force in drive systems, especially in vehicle technology, face challenges due to geometric and magnetic inaccuracies, contamination, vibrations, and limited robustness, which can lead to unsafe conditions and accidents, particularly in electric vehicles with drive-by-wire technology.
Innovation Solution
A method using non-contact measuring sensors with firmly connected measuring standards to determine position shifts in multiple spatial directions, allowing for accurate measurement of torque and force by correcting for manufacturing and thermal inaccuracies, and enabling redundant torque determination for error detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical force or torque measurement systems are used, then direct measurement of torque and force is achieved, but the systems exhibit limited robustness under operating conditions with contamination, vibrations, and wide temperature ranges
Solution Approach 1:
The patent replaces mechanical contact-based torque measurement systems with a magnetic field-based measurement system. Magnetic sensors detect the magnetic field generated by a magnet coupled to the rotating element, enabling torque measurement without mechanical contact. This substitution eliminates wear, contamination, and vibration issues associated with mechanical systems while maintaining measurement accuracy under harsh operating conditions.
2Measurement precision
If averaging torque over one revolution is performed, then measurement accuracy is improved, but response time increases too long resulting in excessive vehicle movement
Solution Approach 1:
The patent performs preliminary characterization of the magnetic field signal during normal operation to establish reference values and correction factors. This preliminary action enables real-time torque calculation without requiring a full revolution averaging process, thus maintaining fast response time while ensuring measurement accuracy through pre-established calibration data.
Solution Approach 2:
Instead of requiring complete averaging over one full revolution, the system uses partial averaging or real-time estimation based on the magnetic field signal characteristics. This partial action approach provides sufficiently accurate torque measurement for safety-critical responses without the time delay of complete revolution averaging, enabling immediate detection of unintended torque.
3Measurement precision
If multiple tracks with different orientations are used to generate absolute signal, then position determination accuracy is improved, but device complexity increases
Solution Approach 1:
The patent uses a single magnetic sensor that performs multiple functions: it detects both the amplitude and phase of the magnetic field signal to determine both radial and axial displacements simultaneously. This multi-functionality approach achieves the position determination accuracy that would otherwise require multiple specialized sensors or tracks, while significantly reducing device complexity.
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
This approach provides reliable and precise measurement of torque and force even at standstill or slight movement, enabling effective error detection and prevention of unwanted vehicle movement, thus enhancing safety and reducing the risk of accidents.
Implementation Method 1
a first magnetic sensor (6.1) arranged on the first bearing ring (3) with a sensor surface facing in an axial direction relative to a longitudinal axis of the second bearing ring (5), and a second magnetic sensor (6.2) arranged on the first bearing ring (3) with a sensor surface facing in a radial direction relative to the longitudinal axis of the second bearing ring (5)
Data Source
Figure 1~2b
Figure 3
Figure 4
AI summary
The invention relates to a method for determining shifts in position in at least two different spatial directions between a first element and a second element which are movable relative to each other, with at least two sensors which measure contactlessly and are spaced, in the at least two different spatial directions, from at least two standards which are fixed to the second element, sensor areas of the at least two sensors opposing the at least two standards in the respective spatial direction and sensing said standards, wherein: - the at least two sensors scan the at least two standards and generate, in interaction with the at least two standards, output signals with which in combination an absolute position of the second element is determined, said absolute position being associated with a linear movement in a further spatial direction or with a rotary movement, and - wherein the output signals of the at least two sensors are also used to determine values which characterise the distance between the respective sensor and the corresponding standard of the second element in the associated spatial direction, are corrected as a function of the determined absolute position of the second element, and from which the shift in position of the second element relative to the first element in the respective spatial direction is determined.