Development of adhesion control strategy based on nonsingular fast terminal sliding mode method

The operation of vehicle might be significantly affected by environmental factors such as rain, snow, oil, and friction modifiers, leading to the slipping and friction induced torsional vibration of wheel. To address this issue, a new method for extremum seeking control and adhesion controller should be developed. In terms of extremum seeking control, current sliding mode extremum seeking control method cannot acquire the optimal slip velocity quickly without unnecessary oscillations. Therefore, a search method for the optimal slip velocity is proposed in this research, by integrating sliding mode extremum seeking control with perturbation extremum seeking method. As to the controller, current sliding mode control method need the real-time resistance information as an input. However, this resistance information in real time is difficult to acquire for a vehicle in operation. To address this problem, the nonsingular fast terminal sliding mode control method is applied innovatively in this research. The results show that although the resistance in real time is unknown, the adhesion control strategy developed in this research can still improve the torque response speed by 5 times, and reduce the torque overshoot by 80%, improving traction efficiency, minimizing wheel slip and speed fluctuations, and mitigating wear of wheel/ rail system.