Proposal for using Sine With Dwell on low friction for the evaluation of yaw stability for heavy vehicle combinations

This paper proposes how the test case Sine With Dwell could be modified for the evaluation of yaw stability of heavy vehicles. The test case was originally proposed by the National Highway Traffic Safety Administration (NHTSA) for evaluation of Electronic Stability Programs (ESP) performance during an oversteer situation on high friction. The modified test case presented here accounts for the heavy vehicle dynamics through three main modifications of the original test case. Firstly, to avoid rollover, the test case is performed on low friction. Secondly, to avoid excess understeer behaviour, the steering input frequency is lowered compared to the original test. Thirdly, to account for response times, the responsiveness and stability criteria are modified. These modifications are derived from hardware in the loop simulations and field tests for different tractor/truck and trailer combinations. By using the modified responsiveness and stability criteria it was shown that the tested ESP system could be objectively evaluated. A clear improvement on vehicle stability was seen in the results when ESP was used.