TDK launches InWheelSense multi-directional power generation and sensing solutions

     InWheelSense is a multi-azimuthal power generation and sensing solution that can be mounted on automotive wheels to convert the force of tire rotation into piezoelectric electricity for battery-free sensing and data acquisition and transmission in harsh environments such as wheels, where power supply is very difficult. The module can sense road conditions, wheel positioning, tire pressure and other conditions in real time, and can connect with roadside infrastructure to help enable smart mobility. InWheelSense is a self-contained, all-inclusive technology platform with power, sensing and connectivity, all contained within the wheel, that will help improve safety and comfort in the next generation of autonomous vehicles and intelligent transportation scenarios.

     To date, environmental sensing of ADAS characteristics has been primarily driven by sensing sensors such as LiDAR, radar, images, and infrared cameras. While these sensors provide valuable data for ADAS operations, the challenges of false positives and false negatives remain. To improve sensing performance in adverse weather conditions or all terrain conditions, non-sensing sensors embedded in tires or wheels, such as piezoelectricity, inertial measurement units (IMUs), ultrasound, and strain gauges, can more accurately digitise and classify driving and road conditions.

     The InWheelSense energy harvesting module uses piezoelectric elements to generate electrical energy from mechanical motion or force. The module is placed at the boundary between the tire and the wheel and can use the force generated by the road surface as the tire rotates to generate electricity. With multiple devices connected around the wheels, the module enables scalable power generation depending on the load of the drive system, achieving an average continuous power output of 1mW when traveling at speeds of 65mph/105km/h. This permanent power supply is ideal for digitizing driving, road and tire conditions using a range of non-perceptual sensing technologies.

     Because changes in speed, cornering and other operating conditions can cause changes in the electromotive force characteristics of the device, the InWheelSense module can sense various driving conditions by analyzing the waveforms generated by the piezoelectric effect and using these power changes. The tire will output a waveform when it touches the road, so it will continuously produce a waveform when the car starts to drive. With the increase of speed, the frequency of waveform generation also increases, when the driving direction changes, the load on the tire will also change, resulting in a different waveform reflecting the driving characteristics at that time. Since the wheel outputs a waveform for each revolution, the InWheelSense module is able to detect not only the speed during driving, but also the road condition based on the shape of the output waveform.

     The InWheelSense platform also allows data to be collected in real time from other wheel sensors, including accelerometers, air pressure and temperature, to onboard computing units. The control module platform includes power management, digital computing power, and low-power data transmission utilizing BLE. Data can be stored and/or processed by a reasoner in the control module that is powered by an edge application processor that enables algorithms to make meaningful inferences in real time. This enables low latency control responses in severe weather conditions without relying on the cloud. The energy harvesting generator provides all the power needed for data acquisition, processing, and operation (transmission).

     InWheelSense's piezoelectric-based energy harvesting and sensing modules are powerful and reliable power sources as well as high-dynamic range sensing devices for tires and driving strips, enhancing the safety of smart mobile vehicles. These non-sensing sensors can work with connected traffic infrastructure such as smart Bridges, traffic control and signage to transmit real-time data and support vehicle-to-pedestrian networks, vehicle-to-infrastructure networks, vehicle-to-vehicle networks.

     InWheelSense also offers an evaluation kit dedicated to a simple evaluation of energy harvesting modules attached as samples to existing wheels. The kit wirelessly collects data from the device's output to generate electricity without the need for additional equipment.