TDK Introduces InWheelSense Energy Harvesting and Sensing Modules

     InWheelSense is a multi-directional power generation and sensing solution that attaches to the wheel of the car, converts the force of tire rotation into piezoelectric energy, and enables battery-free sensing and data collection transmission within the wheel, even if it is transmitted The harsh environment with difficult power supply can still be dealt with. The module can sense road conditions, wheel alignment, tire pressure, etc. in real time, and can also be connected to roadside infrastructure to help enhance intelligent mobility. InWheelSense™ is a self-contained, turnkey technology platform with power, sensing and connectivity, placed entirely within the wheel, helping to improve safety and comfort in next-generation autonomous driving and intelligent transportation scenarios.

     Currently, environmental sensing for ADAS features is mainly driven by perception sensors such as lidar, radar, image and infrared cameras. Although these sensors provide valuable data for the operation of ADAS, the challenges of false positives and false negatives still exist. To improve sensing performance in severe weather or all-terrain conditions, non-sensing sensors such as piezoelectrics, inertial measurement units (IMUs), ultrasonics, and strain gauges embedded in tires or wheels can more accurately detect driving and road conditions Digitize and classify.

     The InWheelSense energy harvesting module utilizes piezoelectric elements to generate electricity from mechanical motion or force. Placed at the boundary between the tire and the wheel, the module uses the force it receives from the road surface as the tire rotates to generate electricity. At the same time, the module allows multiple device connections along the circumference of the wheel, it can generate scalable power generation according to the load of the drive system, and achieve an average continuous power output of 1MW when traveling at a speed of 105km/h (about 65 miles/h). This permanent power source is ideal for a range of non-sensing sensing technologies such as digital driving, road tire condition monitoring, and more.

     Since changes in speed, switching, and other operating conditions can cause changes in the device's EMF characteristics, the InWheelSense module can use these power changes to sense various driving conditions by analyzing the waveforms generated by the piezoelectric effect. The waveform is output when the tire touches the road, so when the car starts driving, the waveform is generated continuously. As the speed of the vehicle increases, the frequency of the waveform also increases. When the driving direction changes, the load on the tire will also change, resulting in different waveforms that reflect the driving characteristics at that time. Since a waveform is output per revolution, the InWheelSense module can not only detect the speed during driving, but also detect road conditions based on the shape of the output waveform.

     The InWheelSense platform also allows real-time data collection from additional wheel sensors (including accelerometers, barometric pressure and temperature) to the onboard computing unit. The control module platform includes power management, digital computing capabilities, and Bluetooth Low Energy data transfer. Data is stored and processed by an inference engine in the control module, powered by an edge application processor, enabling algorithms to quickly make meaningful inferences. This enables low-latency control responses in severe weather conditions without relying on the cloud. All electricity required to support data collection, processing and transmission is provided by energy harvesting generators. The InWheelSense piezoelectric energy harvesting and sensing module is a powerful and reliable power source for high dynamic range sensing of tires and driving conditions, improving the safety of intelligently driven vehicles. These non-sensing technology sensors can interconnect and work together with infrastructure such as smart bridges, traffic control, and signage, enabling real-time data communication, enabling vehicle-to-people, vehicle-to-vehicle, and vehicle-to-infrastructure networking.

     TDK offers an InWheelSense evaluation kit designed for simple evaluation of energy harvesting modules as a sample that can be attached to existing wheels. The kit can wirelessly collect data output from the device, improving power generation performance without the need for additional equipment.