Research on Optimal Torque Control of Turning Energy Consumption for EVs with Motorized Wheels

This paper aims to explore torque optimization control issue in the turning of EV (Electric Vehicles) with motorized wheels for reducing energy consumption in this process. A three-degree-of-freedom (3-DOF) vehicle dynamics model is used to analyze the total longitudinal force of the vehicle and explain the influence of torque vectoring distribution (TVD) on turning resistance. The Genetic Algorithm-Particle Swarm Optimization Hybrid Algorithm (GA-PSO) is used to optimize the torque distribution coefficient offline. Then, a torque optimization control strategy for obtaining minimum turning energy consumption online and a torque distribution coefficient (TDC) table in different cornering conditions are proposed, with the consideration of vehicle stability and possible maximum energy-saving contribution. Furthermore, given the operation points of the in-wheel motors, a more accurate TDC table is developed, which includes motor efficiency in the optimization process. Various simulation results showed that the proposed torque optimization control strategy can reduce the energy consumption in cornering by about 4% for constant motor efficiency ideally and 19% when considering the motor efficiency changes in reality.

Theoretical Model for Prediction of Turning Resistance of Tracked Vehicle on Soft Terrain

Skid-steered tracked vehicles are commonly used in soft agricultural terrain due to its low ground pressure between vehicle tracks and the ground. However, the sliding and sinkage of the track during a turning maneuver causes considerable turning resistance, which reduces the vehicle's turning ability. Therefore, we constructed a theoretical model that predicts the turning resistance of tracked vehicles—under steady-state conditions on soft terrain—accounting for track sinkage effects and track slip and skid. The results demonstrate that the moment of turning resistance decreases with increased track slip and skid ratio but increases with track sinkage depth. The model-predicted moments of turning resistance for the outer and inner tracks—at a given track sinkage depth and track slip and skid ratio—are in reasonably close agreement with available experimental data. This theoretical model can be employed as a predictor for testing the turning resistance of tracked vehicles operating on a wide range of soils.

Turning Resistance into Passion for Knowledge with the Tools of Agency: Teaching-Learning about Theories of Evolution for social justice among foster youth

We discuss implementing critical-theoretical pedagogy within a collaborative transformative project in a foster care program in the U.S. to showcase the activist role of the educator in providing tools of agency for youth struggling against oppression. This project aimed at enhancing and spurring the residents’ (adolescent boys’) agency through collaborative learning activities. The cornerstone was to explore the ethical-political dimensions of knowledge in connection with the boys’ own thematic universe, thus compelling them to take a stand on social and scientific issues in their own lives, their communities, and the society at large. The topic of evolution was chosen to critically examine erroneous and nefarious assumptions associated with a reductionist version of evolutionary theory that promotes the fallacious and racist, and quite widespread, view that race-based social inequality is biologically determined. This was a view that some boys apparently took up from social discourses and practices in their surrounds. A workshop on evolution led by the first author provided a forum for the boys to discuss their views on such contentious matters as social ranking and presumed inequalities in human potential while confronting outrageous stereotypes about so called “Black inferiority” and whether notions of evolution and human nature support or challenge such views.

Simulation and Testing Verification of Tracked Vehicle’s Steering Process Considering Track Skidding

A steering dynamics model considering track skidding is built, which the kinematical and dynamic characteristic about the track forces, turning resistance moment, turning radius, and angular speed are presented. The results show that the turning radius is about 1.5 times and the turning angular speed is 67% in skid-steer situation, which compared to the calculation results based on traditional theory. Experimental results show that steering model is creditable.

A general theory for skid steering of tracked vehicles on firm ground

A general theory for skid steering of tracked vehicles under steady state conditions on firm ground, taking into account the shear stress-shear displacement relationship on the track-ground interface, is presented. The steering behaviour predicted using the general theory bears a strong resemblance to that observed in the field. The variations of sprocket torques for the outer and inner tracks with turning radius predicted by the general theory are in reasonably close agreement with available experimental data. On the other hand, predictions based on Steeds’ theory developed earlier differ greatly from measured results. Using the general theory, the lateral coefficient of friction used in the conventional method for predicting the moment of turning resistance of the track can be quantitatively determined as a function of turning radius. It is believed that the new theory presented in this paper provides a unified approach to the study of the mechanics of skid steering of tracked vehicles and that it may be extended to the study of transient handling behaviour of tracked vehicles.