Dynamic Tire Pressure Sensor with Magnetostatic Energy Harvesting
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Solution Overview
Problem
Current infrastructure inspection methods are inefficient and require external impact sources, leading to slow data collection and sensitivity to ambient noise, while existing energy harvesting technologies for sensor networks face limitations in power density and adaptability.
Innovation Solution
A real-time Dynamic Tire Pressure Sensor (DIPS) system that uses the tire as a natural excitation source for non-destructive acoustic sensing and a rotating energy harvester based on magnetostatic coupling to power the sensor network, enabling continuous operation and high-resolution data collection during vehicle movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external impact sources are used for acoustic sensing, then acoustic signals can be generated for infrastructure inspection, but data collection becomes slow and the system becomes sensitive to ambient noise
Solution Approach 1:
The tire serves as both the vehicle for infrastructure inspection and the excitation source for acoustic sensing. As the tire rotates and contacts the road surface, it naturally generates acoustic signals that propagate through the infrastructure being inspected, eliminating the need for separate external impact sources and enabling continuous data collection during normal vehicle operation
Solution Approach 2:
The system transitions from static impact-based excitation to dynamic rotation-based excitation. The rotating tire continuously generates acoustic signals at varying frequencies and amplitudes as it moves along the infrastructure, enabling real-time monitoring without requiring the infrastructure to be stationary or the inspection process to be interrupted
2Measurement precision
If external impact sources are used for acoustic sensing, then acoustic signals can be generated, but the inspection process requires manual operation and intervention
Solution Approach 1:
The rotating tire automatically generates the excitation signals needed for inspection, and the sensor system continuously records acoustic responses without requiring manual triggering. The system self-regulates the inspection process by maintaining continuous contact with the infrastructure through normal vehicle movement, eliminating the need for manual operation at each measurement point
Solution Approach 2:
The system continuously monitors acoustic signals generated by tire-road interaction and uses real-time feedback from these signals to adjust monitoring parameters. The acoustic responses provide immediate information about infrastructure conditions, enabling automated decision-making about inspection coverage and anomaly detection without manual intervention
3Measurement precision
If traditional batteries are used to power sensor nodes, then the TPMS can measure static pressure, but the system cannot provide high sampling rates or real-time dynamic pressure monitoring
Solution Approach 1:
The patent replaces chemical energy storage (batteries) with mechanical energy harvesting from tire rotation. The rotating tire drives a generator that converts mechanical kinetic energy into electrical energy, providing continuous power for high-rate sampling without the weight and capacity limitations of battery systems
Solution Approach 2:
The energy harvesting system operates continuously as long as the tire rotates, providing uninterrupted power for real-time pressure monitoring. Unlike batteries that deplete over time, the mechanical energy from tire rotation is continuously available during vehicle operation, enabling sustained high-speed sampling without interruption
4Use of energy by moving object
If existing energy harvesting technologies are used for sensor networks, then some power can be generated, but the power density is insufficient for continuous operation
Solution Approach 1:
The energy harvesting system is integrated directly into the tire structure, with multiple harvesting elements distributed around the tire circumference. This segmentation allows each element to contribute to the total power output, achieving sufficient power density through cumulative effect while maintaining a compact form factor suitable for tire integration
Solution Approach 2:
The system combines multiple energy conversion mechanisms within the tire, including piezoelectric materials for vibration harvesting and electromagnetic generators for rotational energy conversion. This composite approach maximizes power density by capturing energy from different motion modes simultaneously
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 DIPS system allows for fast, non-destructive inspection of road and bridge conditions with reduced noise interference and provides sufficient power for continuous operation of the sensor network, enabling real-time monitoring and precise data collection without disrupting traffic or requiring frequent battery replacements.
Implementation Method 1
a rotating energy harvester based on magnetostatic coupling to power the sensor network
Implementation Method 2
Tire and road surface interaction produces acoustic signals, and these signals are measureable with an acoustic transducer
Data Source
AI summary
An instantaneous/real-time wireless dynamic tire pressure sensor (DTPS) for characterizing pavement qualities and for detecting surface and subsurface pavement defects under normal driving conditions. Signal processing provides quantitative assessment of surface conditions. DTPS includes a vehicle tire valve stem-mounted pressure sensor and wheel hub-mounted signal conditioning, amplification, and transmitting circuitry. A signal processing computer within the vehicle is wirelessly coupled to the hub-mounted circuitry. Tire pressure changes caused by ground vibration excitation from the interaction between the tire and pavement at normal driving speeds are detected. When acoustic radiation from a surface wave is significantly stronger than acoustic noise, subsurface information can be extracted. An energy harvester based on strong magnetostatic coupling between a high permeability core solenoid, fixed proximate a vehicle wheel, and a bias magnet array, fixedly mounted in conjunction with a dust shield, can provide power the DIPS.