The Independent Steering and Driving Vehicle: Design, Energy Efficiency and Parking Analysis.

摘要

Throughout the history of human civilization, vehicles have played a significant role by connecting people in various locations. They have thus boosted the progress of civilization and made our lives more convenient. However, as the number of vehicles on the road has increased, the convenience, which vehicles provide, has gradually turned into inconvenience in three respects: 1) the energy consumed by vehicles accounts for a large proportion of total energy consumption, which is in an ever-increasing trend; 2) more parking space is needed, a significant proportion of which is not for parking itself but for enabling the vehicle to be navigated to its final parking slot; 3) the effort required to park a car is also troublesome, causing the driver to spend much more time in a crowded parking lot.;To alleviate these three problems, I develop a methodology to design an independent steering and driving vehicle (ISDV). It brings together the robotic technologies of steer-by-wire, drive-by-wire, four-wheel-independent-steering, and four-wheel-independent-driving. All four wheels of the ISDV can be steered independently, so that vehicle rotation and translation can be decoupled from each other. Omni-directional motions such as zero radius turning (ZRT) and lateral parking (LP) are realized, thereby enhancing the agility of the vehicle. In contrast with omni-directional wheeled mobile robots, this vehicle is targeted at serving as a human carrier or even as a vehicle carrier in the future.;After describing the development of the ISDV, this thesis studies the energy management which can improve the energy efficiency. It is shown that the traditional electric vehicle (EV) is not capable of managing the energy required for one driving cycle because it has only a single traction motor. This thesis proposes and examines a new way to manage electrical energy in which torque is distributed among different in-wheel motors to achieve a higher level of overall energy efficiency, which has been enhanced and demonstrated in various driving cycles.;Thereafter, the thesis studies two aspects of benefits the ISDV can bring to parking. One is in space efficiency, defined as the ratio of the total space occupied by the vehicle in its final parked state over the whole area covered by the parking lot. Comparison of the ISDV and traditional vehicles in parking proves that the ISDV afford a higher level of space efficiency. The other aspect is the parking time. It is tested experimentally in the hardware-in-loop (HIL) system, and the motions of traditional vehicles, the zero radius turning motion, and the free motion of the ISDV are compared. The less time for parking demonstrates the easiness to steer the ISDV.