Vibration reduction in electric bus during acceleration and gear shifting

Abstract

Electric vehicles have replaced many gasoline vehicles in urban environments. The magnitude of vibrations and emissions from electric vehicles are less than those from conventional gasoline-powered vehicles. However, electric vehicles still have mechanical vibrations, such as those created by the power system. During vehicle acceleration, driveline vibration is very prominent. This work focuses on vehicle vibration caused by the electric powertrain in electric vehicles under rapid acceleration/deceleration and gear shifting. Since the dynamic response of an electric motor is rapid, driving torsional vibration arising from acceleration/deceleration and gear shifting is typically transmitted from driveline to vehicle's body, adversely affecting a driver's comfort. This work presents a novel effective control logic that reduces vibrations from an electric driveline system. This system controls the electric motor to suppress driveline torsional vibration transmitted to the driver's seat, effectively reducing vertical vibrations and enhancing driver comfort. This work conducts simulations and hardware tests. In the development of the driveline and motor control logic, Adaptive Modeling Environment for Simulation analytical software is applied to create the driveline system model. To model structural vibrations, HyperMesh is used, and LS DYNA is applied to simulate free vibration and forced vibration. The analytical results for free vibration are compared with empirical data. The analytical results for driveline dynamics are applied as input for the finite element model to analyze forced vibration. Vibrations from the electric driveline move through the motor mount and frame to the driver's seat track. The simulation results demonstrate this control logic strategy applied to an electric bus motor controller effectively reduces fluctuation in driveline torque during acceleration by up to 84.19% and during gear shifting by up to 44.96%. The reduction in vibration of the driver's seat track during fixed-gear acceleration was maximal at 45.96%, and the reduction during gear shifting was 24.11%.

A Review on Vibrations in Electric and Hybrid Electric Vehicles

“…Table 3 shows analyses carried out on whole-body vibration (WBV) and the results obtained with which it's possible Chen [97] This study carried out simulations and experiments on hardware. To build the driveline device model, the driveline and motor control logic are developed using the adaptive design environment for simulation analytical software.…”

Vibration Protection Systems

“…Excessive vibrations in this frequency range occur from everywhere and seriously affect the operators and passengers. These are polyharmonic vibrations of engines, mechanical aids (control mechanisms) and different types of rigging, random vibrations of the structures and transmission drives, chaotic vibrations of the structures, and working substances of pneumatic and hydraulic mechanisms [36][37][38]. We illustrate in Chapter 10 the results of our experiments in the different fields for some types of automotive technological machines.…”

Steering test of mid-size bus with flexible-body dynamics model

“…The bus CAD model was established with Hyperworks simulation software [1][2][3]. The model file was read into MotionView along with the sets of suspension systems, tires, steering group and connected components to complete the rigid motion model of electric bus body model, as shown in Figure 1.…”