Field operations in rice cultivation, such as dry direct seeding and transplanting, require higher path tracking accuracy of agricultural machinery. To meet the requirements for operational consistency and uniform crop distribution in rice production, we designed an assisted steering control system for wheeled tractors, aiming to assist human operators in achieving precise path tracking during rice field operations.
First, we constructed a driver steering model using data from driving simulator tests, and combined it with the kinematic model of wheeled tractors to develop an integrated vehicle control model that incorporates the driver-in-the-loop. Then, we used a polytopic linear parameter varying system to describe the uncertainties in the model, including time-varying driver model parameters and vehicle speed. Based on this model, an output feedback robust controller was designed to ensure robust stability of the system under uncertainties described by polyhedral sets. Additionally, a region pole placement method was employed to improve the transient response performance of the system. Finally, driver-in-the-loop tests were conducted to evaluate the performance of the designed controller.
The results show that this method effectively enhances the path tracking performance of wheeled tractors while alleviating the physical and mental burdens on the operator. In single lane-change maneuvers and complex serpentine driving conditions, the maximum lateral tracking error is reduced by 66.7% and 55.6% compared with that of the PID control algorithm, respectively, while the physical workload of the driver was reduced by 26.86% and 37.6%, and the mental workload was reduced by 4.2% and 31.3%, respectively.
The proposed control strategy offers a technical foundation for enhancing the operational quality of rice and other crop fieldwork.
| 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 |