Search Results

In recent years we have seen drastic improvements of the accuracy of wheel force transducer (WFT) systems /1, 2 and 3/. These systems in most cases are calibrated just statically. What is the dynamic behaviour of the sensor? What can we expect towards the accuracy of the measured loads on real road surfaces as they are influenced by a number of parameters? In the present paper quantitative results are reported out of a broad investigation of the effects of the following parameters road surface, rim stiffness, tire air pressure, velocity and wet road conditions. The unique Wheel and Tire Testing Vehicle (“Universal Skid Resistance Measurement Device”) of Stuttgart University was used for the measurements on two highways. The WFT-signals are referenced to the multiaxial force sensing of this vehicle. These findings are compared to results derived from a rolling road flatbelt test stand reported in /6/.

A new system has been developed for measuring the driving- and braking-torques acting on passenger car wheels. The RWT (Rotating Wheel Torquemeter) is intended above all for vehicle dynamics applications, particularly the development of control systems for dynamic stability, traction control and ABS, as well as investigations of brake fade, brake judder, measurement of transmitted power and determination of friction values, coast down characteristics, and safety tests. The modular system consists of three main components: The torque sensor, the transceiver head for telemetric signal transmission and the control unit located in the vehicle. The torque-sensing device can be fitted to the vehicle with the aid of hub and rim adapters. This allows rapid installation to different vehicles. The torque measurement is achieved via piezoelectric quartz force sensors.

Wheel force transducers (WFT) play an increasing role in endurance evaluation of road vehicles, ride and handling optimization, tire development and vehicle dynamics. With paper 980262 part I of an investigation of seven WFT–systems was presented. After a general evaluation two systems were compared in more detail. From a more basic interest deeper consideration was given to Angle Error Correction and material selection. This paper reports on part II of the investigation. The general evaluation of present systems on the market is updated and refined including new systems and updated versions. Thus an unique and quick overview is provided mirroring the present status of WFT technology. Special attention is given to systems best suited for applications in tire development, for driving dynamics optimization, active safety and active suspension development as well as in the ride and handling area.