Abstract:

The orchard is usually with a wide area, complex terrain, many trenches, overgrown weeds, high soil moisture and relatively loose soil, which greatly restrict the mechanization and intelligence, and put forward higher standards and requirements for the design of mechanical structure, control system and energy system of Automated Guided Vehicle(AGV). The hybrid automatic navigation vehicle can meet the need of long-distance movement in orchard. In order to explore the appropriate hybrid AGV control system algorithm and energy management strategy, and to reduce the manpower, material resources and time cost of the controller design process, firstly, according to the requirements of the current orchard construction on the terrain and soil, and corresponding to the GB/T 7031-2005, the orchard pavement level was divided into F grade and above. In addition, according to the requirment that orchard AGV needed to adapt to the characteristics of a wide range of terrain, the tracked vehicle model structure was adopted. Using the current hardware-in-the-loop simulation technology, raspberry pie was used as the control system to carry the control algorithm. Matlab and RecurDyn software were used to establish the system real-time simulation model which included energy power system, motor drive system, tracked vehicle driving model and road model. Finally, the hardware-in-the-loop simulation function of series hybrid AGV controller was realized. The simulation results of cascade PID and fuzzy controller control algorithm showed that the fuzzy controller control algorithm could reduce the time cost caused by parameter adjustment, and the response speed was increased by 50% when the steering angle was small. When the steering angle was large, the cascade PID controller produced 10% overshoot, while the fuzzy controller had no overshoot, and the steering was more stable. The simulation verification of energy management strategy based on deterministic rules and instantaneous optimization showed that the instantaneous optimization strategy could reduce fuel consumption by about 13.04%. The results showed that the hardware-in-the-loop simulation platform could be effectively applied to the development of orchard AGV controller, avoiding the control of physical experiments, reduce the cost and greatly speed up the development process.

Key words: orchard, series hybrid, AGV control system, hardware-in-the-loop simulation, motion control, energy model