An anti-slip control strategy with modifying target and torque reallocation for heavy in-wheel motor vehicle

In-wheel motors are used in heavy vehicles such as buses and trucks to improve efficiency and compactness, the safety of which is particularly important. Anti-slip control is applied to road vehicles to improve the active safety performance, and it is necessary for heavy in-wheel motor vehicles. However, the experiment results in this study show that the response delay of motors on the heavy vehicle is larger than that of the passenger car, and the vehicle mass often changes, which brings drawbacks to the rapidity and stability of its dynamics control. For these problems, an improved Proportional-Derivative Control with a modifying desired wheel rotational speed is proposed for the slip regulation. The modifying control target is intended to mitigate steady tracking error, the role of which is similar to the traditional Integral Control. The desired wheel rotational speed is modified through the response in the current period, and then is set as the new target in the next period. Because the anti-slip control of driving wheels on each side is independent, the torque reallocation strategy is introduced to coordinate with the yaw control and take the yaw dynamics into account, which therefore improves the lateral stability. To avoid the excessive driving torque increment causing the slipping phenomenon again, after the anti-slip control finishing, a transition process is applied. Finally, simulations and real vehicle experiments are conducted to verify the effectiveness and flexibility of the control algorithm, and the results indicate that the control strategy has an expected performance.

An Advanced Anti-Slip Control Algorithm for Locomotives Under Complex Friction Conditions

The locomotive wheelsets configured with high-power AC traction motors are very prone to slip under poor friction conditions, which usually impair traction/braking efficiency. To avoid the adverse consequence caused by the conspicuous slipping behaviors of wheels, the anti-slip control modules are consequently equipped on high-power locomotives. This paper presents an advanced anti-slip control algorithm for heavy-haul locomotives travelling with complex wheel/rail friction conditions. The proposed anti-slip control model is implemented in a three-dimensional (3D) heavy-haul train-track coupled dynamics model, in which the real-time estimation of wheel/rail adhesion conditions and relevant optimization adjustment of control threshold values are considered. The wheel/rail dynamic interactions of the heavy-haul locomotive under traction/braking conditions and multifarious friction conditions are investigated. The control effects of the anti-slip controllers with changeable and constant threshold values are compared. It is shown that the traction/braking loads and friction conditions have a significant effect on wheel/rail interactions. The optimal traction/braking efficiency can be realized by adopting the anti-slip controller with alterable threshold values.

Sliding Mode-Based Slip Control of Compact Electric Vehicle Truck for Varying Load and Yaw Rate

Vehicle stability is a critical problem, especially for compact electric vehicle (EV) trucks, owing to the impact of the cargo weight and cornering characteristics. In this study, this problem was approached by mathematically formulating the change in the understeer characteristics of an EV truck as variable mass understeer gradient (VMUG) according to the vehicle cargo weight to design the reference yaw rate without the need to consider cornering stiffness. Comparison was made with the conventional methods by applying the VMUG-based slip control while simulating the yaw rate and side-slip tracking performance of the compact EV model for normal loading and overloading conditions. The simulation results demonstrate the superior performance of the proposed method compared to the existing methods. The proposed method has the potential for application for stability enhancement in non-electric and general-purpose vehicles as well.

Improved Analytical Method for Interfacial-Slip Control Design of Steel–Concrete Composite Structures

Interfacial performance is quite significant for maintaining the structural performance of steel–concrete composite structures. Quantitative assessment on the interfacial effect is critical. For this reason, theoretical investigation on the interfacial interaction of steel–concrete composites was performed, with the symmetry of the model considered. Influence of interfacial slip on the mechanical properties of the composites was considered. Analytical solutions of the interfacial slip and strain were provided. The accuracy of the predictions from the improved analytical model was validated by comparing them against the results from experimental and numerical studies. The influence of design parameters of the composite members on the interfacial effect was discussed. The proposed analytical model was also employed to assess the effect of the bond developing at the interface between concrete and steel on the deformation exhibited by simple composite structural forms (e.g., beams). Through the analysis, the priority design parameters of the composite structures are determined for controlling the level of interfacial slip in order to achieve optimum bearing capacity. Different to commonly used energy methods, numerical methods and finite element methods, the study provides a simple and straightforward analytical solution for describing the interfacial interaction of composite structures for the first time, which can act as scientific instruction for the interfacial slip control of composite materials and structures.