In order to enhance the vehicle’s maneuverability and steering flexibility, a literature review is conducted to analyze the structures, technical applications, and controlling schemes of four-wheel steering systems, and summarize the main research methods and application outcomes of automotive four-wheel steering technology. Currently, the developement of automotive four-wheel steering systems is characterized by electrification, intelligence and integration. The four-wheel steering system is transitioning from the classic mechanical passive structure to a more mature electric active four-wheel steering structure. The control schemes for four-wheel steering systems have evolved from single-performance four-wheel steering control technology towards more complex multi-system integration and active fault-tolerant control technology. In the future, electrification, modularity, precision, speed,and safety-reliability are trends for advanced four-wheel steering systems, which are also effective ways to enhance the vehicle maneuverability and steering flexibility.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |