Tip-in Condition Research Articles

Toward better drivability: Investigating user preferences for tip-in acceleration profiles in electric vehicles.

Vehicle drivability, defined as the smooth operation and stability of a vehicle in response to driver inputs, significantly influences the performance of passenger cars. Among various driving conditions, tip-in acceleration is one of the most frequently encountered and crucial factors affecting drivability. This study investigates preferred longitudinal acceleration profiles for electric vehicles through subjective evaluations obtained from on-road tests. Five distinctive acceleration profiles were designed for tip-in conditions and evaluated by 15 highly experienced experts using the paired comparison method. Evaluations were conducted across three scenarios: light tip-in at 30 km/h, middle tip-in at 30 km/h, and middle tip-in at 60 km/h. Experimental results revealed distinct preferences based on driving conditions. For light tip-in at 30 km/h, drivers favored linear acceleration profiles with smaller jerk magnitudes and kurtosis. Conversely, for middle tip-in conditions at both 30 and 60 km/h, drivers preferred acceleration profiles exhibiting rapid initial acceleration followed by a smooth transition. However, at 60 km/h, a preference for higher jerk and steeper gradients was observed. Correlation analyses provided insights into the relationship between subjective preferences and dynamic characteristics of acceleration profiles. This study contributes practical guidance for designing optimal acceleration profiles aligned with driver preferences, thereby enhancing drivability and overall user experience in electric vehicles.

Backlash Traversal Control for Electric Vehicles under tip-In Conditions

Backlash Traversal Control for Electric Vehicles under tip-In Conditions

A novel objective evaluation method of drivability for passenger cars considering subjective and objective consistency

In this paper, aiming at the problems that the random mixed working conditions are difficult to identify, the insufficiency of drivability evaluation indicators system and the lack of robustness for the evaluation model, a novel objective evaluation method of drivability for passenger cars is proposed. First, combining the sliding time window method and Naive Bayesian model (NBM), a hybrid working condition recognition model of multi-source sensor information fusion is constructed, and the real vehicle test under random mixed working conditions shows that the accuracy of working condition identification can reach 95.6%. Then, the objective evaluation index for crawling conditions, starting conditions and tip-in conditions are studied according to the suggestions of subjective evaluation engineers, an objective indicator evaluation system considering expert knowledge and information redundancy between indicators is constructed, among them, R-type clustering and principal component analysis (PCA) are used to eliminate the information redundancy between objective indicators. Finally, based on the back propagation (BP) neural network to optimize the fuzzy membership function, an improved fuzzy comprehensive evaluation (Improve-FCE) method considering subjective and objective consistency is designed. Real vehicle test and analysis results demonstrate that the development of intelligent drivability objective evaluation tool (I-DOET) has good reliability and stability, the maximum subjective and objective relative error of the improved FCE model is 5.13%, and the pass rate reaches 93.3%.

Receding Horizon LQT Control for Vehicle Driveability under Tip-in Condition

Abstract When the vehicle is under the Tip-in condition, the low-frequency longitudinal vibration occurs which generates a large jerk and makes a bad impact on the riding comfort. Under the Tip-in condition, the vehicle dynamic performance requires quick engine torque rise process, while quick torque rise process will lead to bad riding comfort. Therefore, in this paper an engine torque compensation controller is designed taking vehicle driveability as the optimization goals, and using the vehicle jerk limit as the boundary condition. First, according to the vehicle dynamic analysis, the control-oriented model of the vehicle driveline is established and verified by the real vehicle experimental data. Second, the Receding Horizon Linear Quadratic Tracking (RHLQT) algorithm taking vehicle acceleration as the tracking target is designed. Finally, by simulating on the hardware-in-the-loop (HIL) platform, the vehicle driveability under the control of the RHLQT, PID and the torque rising slope limit method are compared and analyzed. The result shows that the proposed control algorithm can achieve both good dynamic performance and acceptable riding comfort of the vehicle.

Application of fuzzy dynamic weights drivability evaluation model in tip-in condition

Only the subjective or objective method is employed to calculate the index weight in the evaluation of drivability, which makes the evaluation result less accurate. In this paper, a drivability evaluation model was proposed on the basis of fuzzy dynamic weights, and the drivability was evaluated in tip-in conditions. The evaluation indexes affecting drivability in tip-in conditions were determined using multi-dimensional analysis. The dynamic weight was built using an improved analytic hierarchy process and improved entropy method in accordance with the principle of “function driving and difference driving.” The fuzzy matrix was built by drawing upon the improved membership function of the evaluation index. Finally, the drivability evaluation model of the tip-in condition was built with dynamic weight and fuzzy matrix. The evaluation model was employed to evaluate the drivability of the vehicle, which obtained the drivability score. As the experiment results suggest, the evaluation model is accurate and effective in comparison with the real score and the score obtained from the fuzzy analytic hierarchy process. The evaluation model is employed to formulate a control strategy for a vehicle that will allow better drivability. Besides, the method makes the performance development of the vehicle more knowledgeable and agile.

A Study on Control Strategy under Tip-In Condition Based on AMT Vehicle

The control strategy of gear-position optimization of an AMT vehicle under Tip-in condition is presented in this article. The down-shift principle of an automatic transmission under an acceleration condition is also analyzed. The in-the-loop simulation platform of transmission system software of an AMT vehicle is established using the Matlab/Simulink. The simulation platform mainly includes the vehicle load module and the control strategy module. The vehicle load module mainly includes the driver intention module, the transmission model, the engine model, the synchronizer model, the clutch model and the resistance model. The hard-acceleration condition is simulated under no deceleration condition by utilizing the optimized control strategy and conventional control strategy respectively. The result indicates that the proposed control strategy can identify a drivers intention, decrease shift times, reduce power interruption time, improve comfort and make the vehicle reach the maximum speed quickly.

An experimental study for drivability improvements in vehicle acceleration mode

Modern vehicles require a high degree of refinement, including good drivability. Vehicle drivability, which becomes a key decisive factor for marketability, is affected by many parameters such as engine control and the dynamic characteristics in the drivelines. Therefore, engine and drivetrain characteristics should be analysed to achieve a well-balanced vehicle response simultaneously. This paper describes experimental procedures that have been developed to measure engine torque and investigate shuffle characteristics. A simplified powertrain model is presented for vehicle dynamic response analysis. Submodels within the model are the engine and drivetrain. Using this model, the friction and inertial moment for each submodel were measured, and effects of parameters were analysed. To analyse vehicle dynamics behaviour, frictional torques and the rotational inertia moment of the engine and the drivetrain were measured. Shuffle characteristics at the tip-in condition were investigated in an experimental vehicle at the second and third gear stages. It was found that shuffle characteristics are caused by sudden changes in engine torque and have a different vibration frequency with gear stage variation. The rotational inertia moment of the engine, including flywheel rotation, is a key factor influencing the shuffle characteristics.