6X6 인휠구동차량 주행성능 향상을 위한 설계방안 및 제어전략에 대한 연구

Abstract

Generally, In-wheeled vehicle can achieve effective TCS(Traction Control System), ABS(anti-Brake System) and VDC(Vehicle Dynamic Control) function without complicated control system additionally. It also has excellent control capability in comparison with engine type vehicle because the response torque command is very fast and precise. the torque of each wheel of in-wheel drive system can be controlled independently, so this system is useful to improve characteristic of vehicle lateral motion., Structurally, it can remove complex mechanical power transmission structure, so it can make the best installation of inside space of vehicle. Because of these advantages, it usually applies to hybrid and electric military unmanned ground vehicles as a representative driving system. However, In-wheel drive system should be carefully designed to keep good stability against external friction force and lateral force. In order to install it into a vehicle effectively, it needs technical guarantee of overall durability including efficiency of motor cooling during high-speed off-road maneuvering. Skid-steering method which applied to the in-wheeled vehicle has good mobility because it doesn't need a cornering radius but discrepancy between desired direction and wheel rotating direction cause friction force which makes rough steering motion of vehicle. so it has poor maneuverability at high-speed steering. Moreover, a friction force having different amount and direction occurs in each wheel, so it needs to be analyzed to get driving safety by slip ratio control. In this system, the problems of complex chassis control such as dynamic road condition and driving/steering characteristics of vehicle should be considered simultaneously. Although worldwide automotive makers such as Japan and U.S., major universities and research institutes are co-developing on in-wheel drive system, But it is difficult to find the successful output and practical results except NREC(National Robotic Engineering Center) which is CMU(Carnegie Mellon University) research group. Until now, various control method have been proposed and compared in view of independent vehicle motion such as slip control, yaw control and position control relating pitching/rolling. These researches are still not only in the proposal of theoretical and analytical driving algorithm but also in simple environment like paved road based on light vehicle with low velocity. Especially, most researches of skid-steering type are focused on basic vehicle motion control and it is difficult to find experimental papers related to analysis and validation of driving wheel motion and system capability. In this paper, developed and researched reliable co-simulator and robust driving algorithm for testing about steering and driving performance for 6x6 in-wheeled vehicle and achieved experiment data through the evaluation under the actual environment having the off-road test by means of the vehicle which is especially designed and manufactured. Also, analytic parameters is verified by experimental and analytical comparison using newly developed ADAMSTM-Matlab�� Co-simulator. Additionally, in this paper proposed advanced in-wheel driving strategy in view of integrated control algorithm with theoretical description. finally, In the future, based on this paper, it is necessary to study the advanced control algorithm continuously which can improve dynamic characteristics and overcome the velocity limitation of SSV.