Experimental Validation of Various Temperature Modells for Semi-Physical Tyre Model Approaches

Abstract

Abstract. With increasing level of complexity and automation in the area of automotive engineering, the simulation of safety relevant Advanced Driver Assistance Systems (ADAS) leads to increasing accuracy demands in the description of tyre contact forces. In recent years, with improvement in tyre simulation, the needs for coping with tyre temperatures and the resulting changes in tyre characteristics are rising significantly. Therefore, experimental validation of three different temperature model approaches is carried out, discussed and compared in the scope of this article. To investigate or rather evaluate the range of application of the presented approaches in combination with respect of further implementation in semi-physical tyre models, the main focus lies on the a physical parameterisation. Aside from good modelling accuracy, focus is held on computational time and complexity of the parameterisation process. To evaluate this process and discuss the results, measurements from a Hoosier racing tyre 6.0 / 18.0 10 LCO C2000 from an industrial flat test bench are used. Finally the simulation results are compared with the measurement data. IntroductionWith enhanced integration of simulation and modelling into vehicle development and assistance systems, the requirements for simulation models regarding precision and computational time are increasing rapidly. In this case, not only demands affecting vehicle modelling but also tyre modelling become more important. In recent years, with improvement in tyre simulation, the needs for coping with tyre temperatures and the resulting changes in tyre characteristics are rising significantly. These changes include, amongst other things, the temperature dependent behaviour of friction coefficients and the loss of cornering stiffness with increasing temperature. To account those effects in modern assistance systems, it will become mandatory to reliably estimate tyre temperatures with information gathered from sensors or state estimators the vehicle can provide. This needs to be done in real time and therefore a reasonable compromise between accuracy and computational time has to be achieved. To generate a comparative basis three different models are tested in regard of the fulfilment of the requirements mentioned. To keep the effort needed for parameterisation as low as possible, the models were designed to handle the simulation with little to no information about the car itself and instead focusing on properties derived from tyre measurements.

Tonne Kilometre Per Hour (TKPH) Prediction for Lifetime Tire Estimate Using Statistical Analysis: A Case Study at Coal Mine

“…If the speed increases, there will be an increase in tire temperature exceeding 380C, the TKPH value will increase. On the other hand, if the temperature is below 38°C, the TKPH will decrease [24], [25], [26].…”

“…And the tire manufacturer concerned issues technical specifications on the TKPH rating value of the tires it produces [23]. Where TKPH is a function of weight (load) and the number of kilometers in 1 hour of operation at a standard temperature of use [6], [24], [25].…”

Tyre–Road Heat Transfer Coefficient Equation Proposal

“…Considering the above description, Hc is not expected to be a constant but rather a function of the (rolling) tyre footprint-road contact time; in other words, the Hc coefficient should increase with the tyre rolling speed while decreasing with the footprint length, as hinted at also in ref. [29]. The above observation is the basis of the Hc equation development proposed in Section 3.…”

“…For example, Miller [24] suggested a value of 3 × 10 4 W/m 2 K. Smith et al [25] proposed one of the most used values, 1.2 × 10 4 W/(m 2 K), employed, as it is, also by [26][27][28], without any discussion about its validity in relation to the testing conditions. Hackl et al [29] found results significantly lower and around 2 × 10 3 W/m 2 K. Taking into account the above discussion, the Hc range seems rather wide, suggesting that its expression should be more complex than a simple constant. To date, there is no evidence that the value 1.2 × 10 4 W/(m 2 K), even if it is the most used, is the correct one, because as far as the authors' knowledge goes, there is not an extensive validation of such a number for all of the possible tyre use conditions.…”

“…Again, the parameters are in good agreement with the testing conditions and the results are of the same order of magnitude as those found in ref. [29].…”