Millimeter-Wave Metamaterial Position Sensor for Electric Vehicles
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Solution Overview
Problem
Magnetic position sensors in vehicles are sensitive to electromagnetic stray fields, particularly in harsh environments like hybrid and electric vehicles, which affects their accuracy due to external magnetic disturbance fields generated by high current wires.
Innovation Solution
A rotation or linear position sensing system utilizing a millimeter-wave (mm-wave) metamaterial track that converts transmitted electromagnetic signals into receive signals, allowing for the determination of the position of a rotatable or movable target object, immune to magnetic disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic angle sensors and linear Hall sensors are used to measure steering angle and steering torque, then position sensing capability is achieved, but sensitivity to magnetic disturbances increases
Solution Approach 1:
The patent replaces magnetic field-based sensing with electromagnetic wave-based sensing. A transmitter emits electromagnetic waves that interact with a metamaterial structure on the target object, and a receiver detects the reflected or transmitted waves. The metamaterial structure's electromagnetic properties change with position, modulating the wave signal to encode position information. This substitution eliminates sensitivity to magnetic disturbances while maintaining position measurement capability.
Solution Approach 2:
The patent changes the operating principle from magnetic field interaction to electromagnetic wave interaction. By using metamaterials with position-dependent electromagnetic properties (such as permittivity or permeability variations), the system encodes position information in the electromagnetic wave's phase, amplitude, or frequency, rather than relying on magnetic field strength measurements.
2Speed
If magnetic speed sensors are used for camshaft, crankshaft and transmission applications, then speed sensing is achieved, but reliability in harsh electromagnetic environments decreases
Solution Approach 1:
The patent replaces magnetic field-based speed sensing with electromagnetic wave-based sensing. The metamaterial structure on the rotating or moving target modulates the electromagnetic wave signal according to its position and velocity. By tracking the temporal changes in the received signal's phase or frequency, the system determines speed without using magnetic sensors, thereby improving reliability in harsh electromagnetic environments.
3Reliability
If mm-wave metamaterial track is used for position sensing, then robustness against electromagnetic interference is improved, but device complexity increases
Solution Approach 1:
The patent employs a single mm-wave transceiver that can operate in both transmission and reception modes, serving multiple sensing functions. The metamaterial structure on the target object serves as both the position-encoding element and the interaction medium for electromagnetic waves. This multi-functional approach reduces the number of separate components needed compared to traditional multi-sensor systems.
Solution Approach 2:
The patent introduces a metamaterial structure as an intermediary between the transmitter and receiver. This passive structure modulates the electromagnetic wave signal according to the target's position, enabling position encoding without active sensors on the target. The intermediary converts mechanical position into electromagnetic signal variations that can be detected and decoded.
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 system provides accurate position sensing that is robust against electromagnetic interference, enhancing the reliability of position measurements in challenging vehicle environments.
Implementation Method 1
the first mm-wave metamaterial track converts the first electro-magnetic transmit signal into a first electro-magnetic receive signal
Data Source
AI summary
A rotation sensor system includes a rotatable target object configured to rotate about a rotational axis in a rotation direction; a first millimeter-wave (mm-wave) metamaterial track coupled to the rotatable target object, where the first mm-wave metamaterial track is arranged around the rotational axis, and where the first mm-wave metamaterial track includes a first array of elementary structures having at least one first characteristic that changes around a perimeter of the first mm-wave metamaterial track; at least one transmitter configured to transmit a first electro-magnetic transmit signal towards the first mm-wave metamaterial track, where the first mm-wave metamaterial track converts the first electro-magnetic transmit signal into a first electro-magnetic receive signal; at least one receiver configured to receive the first electro-magnetic receive signal; and at least one processor configured to determine a rotational position of the rotatable target object based on the received first electro-magnetic receive signal.