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Wheel force measurement with Virtual Sensors
Aim of wheel force measurement in a car
Today, measurement of the wheel forces and torques of passenger cars and heavy duty trucks is usually done by using Wheel Force Transducers (WFT) from various manufacturers. Sometimes, strain gauges are used as alternative.
Wheel force measurements play a crucial role for:
- reliability engineering in component design: assess vehicle component loads and fatigue
e.g. regarding suspension, car body and drive shaft
- brake tests, to analyze for example what happens in case of full braking
Because of their complexity, wheel force measurements with WFT or strain gauges are currently limited to R&D processes.
What makes wheel force measurement so complex?
- How can a vehicle or equipment manufacturer collect reliable and extensive wheel force data during the R&D phase?
- How to measure wheel forces precisely in series vehicles without laboratory-type hardware?
How does a virtual wheel force transducer work?
Our virtual sensors can measure the forces and torques at the wheels after proper training of the algorithms.
In the first step, the algorithms are trained for a limited time to match target values given by real hardware sensors, i.e. commercially available wheel force transducers (WFT).
- Engine speed and torque
- Wheel speeds
- Longitudinal and lateral accelerations
- Yaw rate
- Steering angle, speed and torque
In a test vehicle driving on a test track, these virtual sensors are tuned for optimal correlation to the target values given by hardware sensors
Then, the virtual sensors for wheel forces and torques can be deployed in a larger fleet of R&D vehicles, while avoiding the shortcomings of unreliable WFT. As virtual sensors are software-based, they need no specific waterproof or anti-schock construction and work w/o adapter: the rim stays in place and nothing changes regarding the mount of the tire. The measurement principle of our virtual sensors does not depend on temperature, it does not suffer from excessive heat input. Virtual sensors need no adaptation for any similar vehicle, they are automatically compliant as long as the vehicle topology remains the same.
What is the output of a virtual wheel force transducer?
Like any hardware WFT, our virtual sensors measure the forces (N) as well as torques M (Nm) at the wheels. After training with appropriate data, we are able to achieve excellent correlation (e.g. about 150 N regarding Fx and Fy) between hardware wheel force transducers and our virtual sensors on front and rear wheels
Wheel force measurement in series cars
Our virtual sensors can be deployed in connected vehicles, so that real-life and highly reliable data can be gathered at scale. This way, every single series-production vehicle can be turned into a test vehicle.
When wheel forces and torques are measured in series-production vehicles, this opens up a broader application spectrum. It allows for instance:
- road load data acquisition in real life for deisgn and dimensioning optimization
- predictive maintenance of vehicle components, e.g. tire wear estimation
- road condition detection
One of our customers, a high-end car manufacturer, gathers precise in-use data with virtual wheel force measurement in series cars. Based on such in-use data, additional services can be offered to the driver or fleet manager, e.g. in terms of predictive maintenance.
xEV vehicle directional stability
Especially for electric vehicles with independent 4WD, an exact estimation of longitudinal force is one of the key input values for lateral stability and path-following control functions.
Other related use case: how to measure steering effort / calculate steering force
We have also developed virtual sensors to measure the forces and torques in the steering system.
Benefits of virtual wheel force sensors
For our customer, this solution means
Get in touch with us to discuss about your Use case!
Contact
+49 (0)6151 3844614
contact@compredict.ai
COMPREDICT GmbH
Rheinstraße 40-42
64283 Darmstadt, Germany