AIM Arnold Intelligente Messsysteme is displaying its latest developments for wheel-force measurement at Automotive Testing Technology Expo Europe, which is taking place this week in Stuttgart, Germany (June 21-23). These include an updated instrumented wheel for two-wheel vehicles and, new to the market, a unit for car applications.
A notable feature of the wheels is the minimalist nature of the sensor housing, without any extraneous external elements. “It was a design criterion to have everything you need inside the vehicle, nothing outside,” said company founder Hans Arnold. “When we made our first [motorcycle] system for a company in Japan that already had wheel-force measurement capabilities, we saw why they wanted a new system. The existing system they had used batteries and outside telemetry, which was complicated to install. Our wheels are just mounted like a standard wheel; you plug in the power supply and a CAN logger, and you can start testing.”
The setup and calibration of the wheel are also very straightforward. “There is stored calibration in the wheel and all you have to do is the zero offset for the signal via the CANbus, and after installation, the angular offset, simply by turning the wheel to a vertical position, checking it with a spirit level and pressing a button,” explained Arnold.
A notable feature of the updated ROLSmc-HD for motorcycles is the use of a wheel assembly made entirely from carbon fiber, used to keep the overall wheel mass the same as a standard unit despite the addition of the instrumentation in the center. Arnold noted that this is very important to ensure representative behavior from the wheel, particularly in terms of its response to high-frequency movement.
The motorcycle and passenger car (ROLS4w) units use a similar circular measuring element, consisting of five strain-gauge-based, three-component measuring elements. The 15 signals from the full-bridge strain gauges (built to the company’s specific design) are amplified and processed using a DSP integrated into the wheel center.