Measurement of contact forces and patch features by means of accelerometers fixed inside the tire to improve future car active control

Abstract

Huge improvements and advances in sensor technology, together with the increasing demand for safety and handling performances, pull research towards new control strategies. Robustness and promptness of sensors used for active control are key requisites. The main idea behind the research presented in this paper is to instrument the tire with appropriate sensors in order to estimate several contact parameters ranging from the kinematic conditions of the tire (the longitudinal slippage and the side slip angle [Fukada, Y., 1999, Slip-angle estimation for vehicle stability control. Vehicle System Dynamics, 32(4–5), 375–388.]) to its dynamic properties (the contact area shape and dimensions as well as the longitudinal, lateral and vertical loads [Cole, D.J. and Cebon, D., 1989, A capacitative strip sensor for measuring dynamic type forces. Proc. of the Second International Conference on Road Traffic Monitoring, London, 38–42; Cole, D.J. and Cebon, D., 1992, Performance and application of a capacitative strip tyre force sensor. Proc of IEE Conference on Road Traffic Monitoring, London, 123–132.]) and to the adhesion characteristics of the road (the surface roughness [Pasterkamp, W.R. and Pacejka, H.B., 1997, The tire as a sensor to estimate friction. Vehicle System Dynamics, 27, 409–422; Pohl, A., Steindl, R. and Reindl, L., 1999, The ‘intelligent tire’ utilizing passive SAW sensorsmeasurement of tire friction. IEEE Transactions on Instrumentation and Measurement, 48(6), 1041–1046; Ray, L.R., 1997, Nonlinear tire force estimation and road friction identification: Simulation and experiments. Automatics, 33(10), 1819–1833.]). Thus, the tire becomes a sensor of tire–road interaction. Clearly, no other measuring device may ever be more robust nor prompt, and anyway closer to the contact area. After a preliminary research in which the pros and cons of the various sensor technologies were taken into account, it was decided to put accelerometers inside the tire. These accelerometers were fixed to the liner and on-board analysis of the acquired data was performed to reduce the amount of data then sent via radio control to a central data processing unit. This unit, through post-elaboration and recombination of the reduced signals coming from the various accelerometers in the tire, estimates some of the above-described contact parameters. In the near future, these contact parameters coming from all four tires and eventually other signals from sensors placed on the vehicle may be used to develop innovative control strategies in order to increase vehicle performances as well as running safety

A novel method for producing low cost dynamometric wheels based on harmonic elimination techniques

“…Consequently, in order to fully understand the dynamic behaviour of the vehicle, accurate experimental data of these contact forces and moments are needed. Several methods can be found in the literature for measuring the forces and torques generated at the tyre/road contact based on the instrumentation of the tyre [1][2][3][4][5] or of the wheel [6][7][8]. The methods based on the instrumentation of the tyre normally require the placement of measurement sensors (accelerometers, optical sensors…) embedded in the interior thereof.…”

Sliding mode-based lateral vehicle dynamics control using tyre force measurements

“…They are calculated from the linear region of the CarSim tyre model. Further, the state and output equations in Equations (1)-(4) are linearised with v = 80 km/h and no steering wheel angle as shown in Equations (5) and (6). The model parameters for linearisation are obtained from the CarSim vehicle model and a CarSim simulation performed at v = 80 km/h while driving straight.…”

“…[6,7] In [6], an indirect method based on accelerometers fixed inside the tyres is proposed. Whereas in [7], a more direct method based on load sensing bearing is proposed.…”

Design and testing of an innovative measurement device for tyre–road contact forces

“…The idea behind the long-lasting cooperation between Politecnico di Milano and Pirelli Tyres is to turn the tyre (and the rim) into a sensor for tyre-road contact force measurement [8]. In particular, a new low-cost tyre-road contact force measurement system is presented in this paper.…”

“…The main stream of such researches is to embed sensors in commercial rims (in order to avoid the use of heavy flanges). Some researchers also try to embed sensors (usually accelerometers but also optical sensors) directly into tyres (for the so-called smart tyres [8,9]) and to reconstruct contact forces from the signals coming from these sensors. Some other researches have developed very high precision and reliability measuring devices that require the re-design of the chassis-suspension connection joints [10].…”