S-Space Graduate School of Convergence Science and Technology (융합과학기술대학원) Dept. of Transdisciplinary Studies(융합과학부) Theses (Ph.D. / Sc.D._융합과학부)
Terrain driving control algorithm for skid-steered in-wheel driving vehicles
스키드 조향 인휠 구동 차량의 험로 주행 제어 알고리즘
- 융합과학기술대학원 지능형융합시스템학과
- Issue Date
- 서울대학교 대학원
- terrain driving; skid-steer; six-wheel; in-wheel motor; torque distribution; control allocation
- 학위논문 (박사)-- 서울대학교 융합과학기술대학원 : 지능형융합시스템학과, 2014. 8. 이경수.
- This thesis describes torque distribution control of six-wheeled skid-steered in-wheel motor vehicles with consideration of friction circle of each wheel to maximize terrain driving and maneuvering performance. To decide desired yaw rate according to drivers steering command, the maximum performance of yaw rate in accordance with vehicle speed and lateral tire force disturbance have been analyzed. In order to satisfy both desired net longitudinal force and desired yaw moment, which are decided in accordance with drivers intension, the torque distribution algorithm determines torque command to each wheel, in consideration of friction circles of all wheels, slip condition and motor torque limitation, based on control allocation method. Vehicle speed estimation algorithm for six-wheeled independent driving vehicles is designed to estimate accurate speed using six wheel speed, acceleration and yaw rate signals. The friction circle of each wheel is estimated using linear parametrized tire model with two threshold values, based on recursive least square method. The response of the six-wheeled and skid-steered vehicle with the proposed torque distribution algorithm and friction circle estimation algorithm has been evaluated via computer simulations using TruckSim and Matlab/Simulink co-simulation. The simulation studies show that the proposed friction circle estimation algorithm is sufficiently accurate even when a wheel is lifting under terrain-driving condition. Hill-climbing and terrain driving performance with the proposed torque distribution and friction circle estimation is enhanced in comparison with proportional torque distribution. Maneuvering performance will be verified via comparison with Ackerman steered vehicles in the near future.