Prof. Dr. Georg Rill
TMeasy represents a handling tire model based on a semi-physical model. The idea goes back to a first approach, where the performance of huge agricultural tractor tires on road was required for an industrial project, but absolutely no tire measurement were available for that kind of tires. Applications to passenger car tires result in the first TMeasy version published in 1994. Based on increasing experiences from passenger car and truck applications, an improved version was developed. Improvements in the discretization of the contact geometry led to version 3.0. Besides some enhancements with respect to MBS integration via the Standard Tire Interface (STI), the version TMeasy 4.0 includes first approaches to dynamic parking torque models. This version was applied for the Tire Performance Test programme (TMPT) organised by the Vienna University of Technology in 2004.
The completely revised version TMeasy 5.0 is based on a three-dimensional slip approach and automatically provides a smooth transition from stand still to normal driving situations including a rather simple but very effective dynamic parking torque model.The handling tire model TMeasy is valid for different kind of tires including motor-cycle and special purpose tires. At present versions 5.3 and 6.0 are available.
Version 6.0 an extension to the standard TMeasy version 5.3, takes the first two rigid body eigenmodes of the belt into consideration. These modes represent the in plane longitudinal and rotational movements of the belt relative to the rim. The dynamics of the longitudinal force is of higher order then and reproduces the tire wheel vibrations, required for indirect tire-pressure monitoring systems (iTPMS) of second generation
TMeasy is valid in all driving situations and provides a smooth transition to stand-still. Moreover, it enables a skilled engineer to estimate appropriate TMeasy parameter by just knowing or estimating the size, the payload of the tire, as well as the friction property of the tire road combination. Of course, the TMeasy parameter can be adjusted to tire or vehicle dynamics measurements by curve fits or just by inspection. The TMeasy tire model requires no initialization. Hence, all TMeasy model parameters can be changed on the fly, which makes it possible to adjust the parameter to sudden changes in the road environment (mu-split) or to simulate a tire puncture for example.
TMeasy 6.1 combines the standard and the extended version of the TMeasy tire model by a model flag which is provided in the tire parameter file.