## 4 Simulation Experiment
### Experiment 2: Simulation of Longitudinal Dynamic Control of Electric Forklift  
The electric forklift, with its advantages of environmental protection, zero emissions, simple operation, and high efficiency, finds wide applications in various industries, including logistics warehousing, manufacturing, port terminals, supermarkets, and logistics parks. The working site of an electric forklift is illustrated in Figure 5. By utilizing electric forklifts, logistics efficiency can be improved, labor intensity reduced, and the goals of energy saving and emission reduction achieved [36]. 1. Structure and composition: A general electric forklift comprises a chassis, cab, fork assembly, power system, and control system. The chassis is the infrastructure of the forklift, which supports and carries the components of the whole forklift. The cab is where the operator works, including the seat, joystick, instrument panel, etc. Fork assemblies are used to load, unload, and carry goods. 2. Power type: Electric forklifts use two main power types: battery and power line supply. Battery-powered forklifts are powered by a battery pack, which has the characteristics of high flexibility and wide adaptability, making them suitable for indoor and outdoor  
Figure 4: System input curves. Figure 5: Electric balanced forklift operating site. operations. Power line-powered forklifts obtain power by connecting to a fixed power line, making them suitable for continuous logistics operations. 3. Load capacity: The load capacity of electric forklifts is usually between 1 and 10 tons. According to different work needs and scenarios, a forklift with an appropriate load capacity can be selected to meet the handling needs. 4. Operation mode: The operation of the electric forklift is usually completed by the operator through control devices such as joysticks, buttons, or touch screens. The operator can control the driving, steering, lifting fork, tilting fork, and other actions of the forklift. 5. Safety and intelligence: Modern electric forklifts are equipped with various safety equipment and auxiliary systems, such as safety warning lights, reverse radar, anti-collision devices, driver status monitoring, etc., to improve operational safety. At the same time, some electric forklifts also have intelligent functions, such as navigation systems, automatic storage devices, etc., which improve work efficiency and accuracy. The drive system is a crucial component of an electric forklift and typically consists of a traction motor, control system (including motor driver, controller, and various sensors), mechanical deceleration and transmission, wheels, and other related components. Currently, there are two common types of speed regulation systems for electric forklifts: DC and AC drives. The operational control of an electric forklift mainly involves the following aspects:  
1. Start and stop: An electric forklift is usually started and stopped by pedals or buttons. When starting, the operator needs to ensure the safety of the surrounding environment and press the start switch or pedal to start the electric forklift. When stopping, the operator needs to release the start switch or pedal, and the electric forklift will stop running. 2. Direction control: Electric forklifts usually use a steering wheel to control the driving direction. The steering wheel is pushed forward to drive the electric forklift forward and pulled backward to drive the electric forklift backward. When turning, the operator can turn to the left or right to select the lever or steering wheel. When making turns, the directional lever or steering wheel is turned to the left or right. 3. Speed control: The speed of the electric forklift can usually be adjusted by the accelerator pedal or the acceleration and deceleration button. 4. Lifting control: Electric forklifts are usually equipped with forklifting functions, which can be used for loading and unloading goods. The lifting and lowering of the fork can be controlled by lifting the lever or buttons.