Shift Lever Position Determination Using Four Orthogonal Sensors
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Solution Overview
Problem
Conventional transmission control systems in 'shift-by-wire' systems inaccurately determine the position of the shifter, leading to incorrect mode operation and requiring extensive calibration, which increases costs and complexity.
Innovation Solution
A system utilizing four position sensors to measure the shift lever's position along orthogonal axes, with a position determination module that determines the shift lever's position based on these measurements, implementing two methods to verify the accuracy of the requested mode of operation by comparing different positional calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional position sensing methods are used in shift-by-wire systems, then the system structure is simpler, but the position determination accuracy deteriorates leading to incorrect mode operation
Solution Approach 1:
The position determination is segmented into multiple independent measurement components. Four position sensors measure along two orthogonal axes (x and y), with each axis providing two independent measurements. This segmentation allows the system to achieve high accuracy through multiple measurements rather than relying on a single complex sensor, resolving the contradiction between accuracy and complexity.
Solution Approach 2:
The system transitions from single-axis measurement to two-dimensional measurement. By measuring position along both x and y axes independently and combining these measurements, the system achieves more accurate position determination than would be possible with a single linear sensor, effectively using dimensional expansion to improve precision without proportionally increasing complexity.
2Measurement precision
If extensive calibration is performed to improve position accuracy, then measurement precision improves, but manufacturing complexity and cost increase
Solution Approach 1:
The system performs self-verification through redundant measurements. The four position sensors provide multiple measurements that can be cross-checked against each other, allowing the system to self-validate position accuracy without requiring external calibration procedures. This self-service approach eliminates extensive manual calibration while maintaining high precision.
Solution Approach 2:
The system uses feedback from multiple position sensors to continuously verify position accuracy. By comparing measurements from different sensors and axes, the system can detect and correct deviations without external calibration, creating a self-correcting measurement system that maintains precision without requiring complex manufacturing calibration processes.
3Reliability
If redundant position sensors are used to improve reliability, then system reliability improves through failure detection, but device complexity increases
Solution Approach 1:
The system merges multiple measurement functions into a unified position determination process. Four position sensors measuring along two axes are combined and processed together to determine shift lever position. This merging allows the system to achieve reliability through redundancy while managing complexity through integrated processing rather than separate independent systems.
Solution Approach 2:
The position sensor system serves multiple functions simultaneously: primary position measurement, accuracy verification, and failure detection. The same four sensors used for position determination also provide redundancy for reliability, eliminating the need for separate dedicated failure detection sensors and reducing overall system complexity.
Data Source
AI summary
A system for controlling a transmission of a vehicle based on input from a shifter includes first, second, third, and fourth position sensors and a position determination module. The shifter includes a shift lever. The first and second position sensors sense first and second positions of the shift lever, respectively, with respect to first and second axes, respectively, wherein the first and second axes are orthogonal to one another. The third and fourth position sensors sense third and fourth positions of the shift lever, respectively, with respect to third and fourth axes, respectively, wherein the third and fourth axes are orthogonal to one another. In addition, the first and second axes are non-orthogonal to the third and fourth axes. The position determination module determines a position of the shift lever based on the first, second, third, and fourth positions.