A small-sized crawler tractor power chassis system

Abstract

The application provides a small-sized crawler tractor power chassis system, which comprises a power source unit for converting chemical energy into mechanical energy and providing original power output; a hydraulic transmission and execution unit for converting the original power into hydraulic energy and driving independent movement of left and right crawlers; an electronic control unit as a core controller of the system; a sensing and monitoring unit for real-time collection of operation parameters including engine speed, hydraulic system pressure, actual crawler speed, machine body posture and operation instruction; the application controls the power source unit and the hydraulic transmission and execution unit through the electronic control unit, realizes energy management of the whole power chain from the engine to the crawler, overcomes the disadvantages of independent work of the power and transmission systems in the traditional system, enables the whole machine to dynamically adjust to the optimal working point under various variable load working conditions, and greatly improves fuel economy and ensures sufficient traction force output.

Description

Technical Field

[0001] This invention relates to the field of power chassis technology, and more particularly to a power chassis system for a small tracked tractor. Background Technology

[0002] As an important power platform for agricultural and engineering machinery, small tracked tractors are widely used in special terrains and scenarios such as paddy field cultivation, orchard management, slope operations, and greenhouses due to their advantages such as low ground pressure, high traction, and good passability. With the development of smart farms, the market has put forward increasingly higher requirements for the ease of operation, operating efficiency, fuel economy, and environmental adaptability of these machines.

[0003] Existing power chassis systems for small tracked tractors primarily focus on optimizing and improving mechanical structures, neglecting system-level integration and intelligent control. First, their power system (engine) and transmission system (hydraulic system) are typically controlled as two relatively independent units, lacking collaborative management and energy distribution strategies based on the overall machine's operating status. This results in inefficiency under varying load conditions, leading to poor fuel economy. Second, traditional systems generally lack sophisticated operating mode selection capabilities, making it difficult to intelligently switch between deep tillage requiring high traction and high-speed, low-consumption transfer modes. Furthermore, they cannot achieve precise fine-tuning at ultra-low speeds, limiting their application in precision agriculture. Third, existing systems often employ a simple mechanical temperature-controlled fan for thermal management, resulting in sluggish response and an inability to dynamically adjust based on actual load conditions. Under continuous heavy loads, this easily leads to hydraulic oil overheating, while under light loads, it wastes fan energy.

[0004] Therefore, in response to the problems mentioned above, this invention proposes a small tracked tractor power chassis system. Summary of the Invention

[0005] To overcome the systemic problems of poor functional coordination, low intelligence, and inability to adapt to multiple operating modes in existing small tracked tractor power chassis systems, this invention proposes a small tracked tractor power chassis system. By introducing an electronic control unit to manage the power source, hydraulic transmission actuators, thermal management unit, and various sensors, and integrating multiple intelligent control strategies, it achieves adaptive switching of operating modes, precise power distribution, and system thermal management, thereby comprehensively improving the overall performance of the chassis system.

[0006] The technical solution of this invention is: a small tracked tractor power chassis system, comprising:

[0007] A power source unit is used to convert chemical energy into mechanical energy and provide raw power output;

[0008] The hydraulic transmission and actuator unit has its input end coupled to the output end of the power source unit, which is used to convert the original power into hydraulic energy and drive the left and right tracks to move independently.

[0009] The electronic control unit serves as the core controller of the system.

[0010] The sensing and monitoring unit is located at key nodes of the chassis to collect operating parameters in real time, including engine speed, hydraulic system pressure, actual track speed, body attitude and operating commands, and transmit the collected data to the electronic control unit.

[0011] The electronic control unit is used to receive multiple operating parameters from the sensing and monitoring unit, and based on the preset control strategy and the received parameters, generates a first control command to adjust the output power of the power source unit, and generates a second control command to independently control the flow and pressure of the hydraulic components in the hydraulic transmission and execution unit used to drive the left and right tracks.

[0012] The control strategy includes at least one adaptive power distribution strategy based on the operating mode, which enables the electronic control unit to adjust the matching relationship between the target engine speed and the target hydraulic system pressure according to the selected operating mode.

[0013] As a preferred option, the adaptive power distribution strategy based on the operating mode includes multiple operating modes, including a high-efficiency transport mode, a high-torque operating mode, and a fine-tuning mode. When the high-efficiency transport mode is selected, the electronic control unit prioritizes reducing the engine target speed and controls the hydraulic system to maintain a low base pressure to minimize fuel consumption. When the high-torque operating mode is selected, the electronic control unit prioritizes increasing the engine target speed and allows the hydraulic system to respond to higher pressure demands to maximize traction output. When the fine-tuning mode is selected, the electronic control unit controls the engine to stabilize at an economical fixed speed and achieves precise control of the track speed by frequently adjusting the hydraulic unit with small amplitude.

[0014] Preferably, the operating mode can be directly selected by the driver via a physical knob or touchscreen interface in the cab.

[0015] Preferably, the system also includes a thermal management unit, which includes a hydraulic oil radiator, a cooling fan and its drive controller. The electronic control unit continuously receives hydraulic oil temperature signals and calculates the heat dissipation requirements based on the current oil temperature, the actual power loss of the hydraulic system and the selected operating mode. Then, it generates a third control command to control the speed of the cooling fan in PWM pulse width modulation mode.

[0016] Preferably, the control logic of the electronic control unit in fine-tuning mode includes: receiving a micro-motion command signal from the operating lever, performing low-pass filtering and dead-zone compensation processing on the signal, and then mapping the processed command signal into a small current control signal for the proportional valve in the hydraulic transmission and actuation unit.

[0017] Preferably, the electronic control unit also includes an anti-slip control strategy: by comparing the actual speed difference between the left and right tracks in real time, and determining that slippage occurs when the speed difference exceeds the safety threshold calculated by the tilt sensor in the sensing and monitoring unit based on the current body attitude information, then by using a second control command to instantly reduce the hydraulic drive pressure of the slipping track and apply a certain amount of power compensation to the non-slipping track.

[0018] Preferably, the anti-slip control strategy can work in conjunction with the power distribution strategy based on the working mode, including: in the high torque working mode, the electronic control unit adopts a higher slippage judgment threshold to allow the track to slip to a certain extent, while in the high-efficiency transportation mode, the electronic control unit adopts a lower slippage judgment threshold to minimize power loss and track wear.

[0019] Preferably, the system also includes a human-machine interface unit, which is communicatively connected to the electronic control unit. The human-machine interface unit is used to allow users to select operating modes, set operating parameters, and display in real time the system status information collected by the sensing and monitoring unit and the efficiency indicators calculated by the electronic control unit.

[0020] Preferably, the electronic control unit continuously calculates and records the fuel consumption per unit area or the workload per unit time, and provides users with work efficiency reports and maintenance reminders based on historical data through the human-machine interaction unit.

[0021] Preferably, the control strategy of the electronic control unit also includes a power pre-allocation function based on load prediction: the electronic control unit can learn and memorize the driver's operating habits in repetitive work sections or repetitive actions, and increase the speed of the power source unit in advance when it predicts that a high load condition will occur.

[0022] Preferably, when the sensing and monitoring unit detects any abnormality in any key parameter or failure of a component, the electronic control unit will automatically degrade the control strategy according to the fault level, by limiting the maximum engine speed, fixing the hydraulic flow, or locking the differential, so that the chassis system can move to a safe area at the lowest functional level.

[0023] The beneficial effects of this invention are:

[0024] 1. This invention controls the power source unit and hydraulic transmission and execution unit through an electronic control unit, realizing energy management of the entire power chain from engine to track. It overcomes the drawback of the independent operation of the power and transmission systems in traditional systems, enabling the whole machine to dynamically adjust to the optimal operating point under various variable load conditions, thereby greatly improving fuel economy and ensuring sufficient traction output.

[0025] 2. By introducing a power distribution strategy based on adaptive operation mode, users are provided with a variety of preset working modes such as high-efficiency transportation, high-torque operation, and fine-tuning. This allows a single piece of equipment to intelligently switch flexibly between different performance indicators such as high economy, high operating capacity, and high operating precision, greatly expanding the application range and work efficiency of the equipment.

[0026] 3. Through the thermal management unit, the system can calculate the heat dissipation requirements and dynamically adjust the cooling fan speed based on real-time oil temperature, system power loss and operating mode. This enables on-demand allocation of heat dissipation capacity, effectively preventing the hydraulic system from experiencing performance degradation or failure due to excessively high oil temperature. It also reduces unnecessary fan energy consumption and improves the system's reliability and durability under harsh operating conditions. Attached Figure Description

[0027] Figure 1 The diagram shown illustrates the workflow of this invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] This invention provides an embodiment of a small tracked tractor power chassis system:

[0030] In this embodiment, the power source unit adopts an inline three-cylinder diesel engine with a rated power of 35kW. The engine is equipped with a high-pressure common rail fuel injection system and an electronic throttle actuator. The engine does not work independently. Its engine controller is connected to the electronic control unit of the present invention via a CAN bus, receives torque and speed commands from the electronic control unit, and uploads data such as real-time engine speed, water temperature and fuel consumption rate to the electronic control unit.

[0031] In this embodiment, the hydraulic transmission and execution unit includes a variable displacement piston pump directly driven by the engine, whose displacement can be steplessly adjusted by the electronic control unit via a proportional solenoid valve. This pump is responsible for converting the input mechanical energy into hydraulic energy. Two variable displacement motors, used to drive the left and right tracks respectively, also have their displacement controlled by the electronic control unit, thereby optimizing system efficiency. A valve group integrating multiple high-frequency response proportional valves is used to receive instructions from the electronic control unit to independently control the hydraulic oil flow and pressure to the left and right motors, thereby realizing stepless speed change and steering of the tracks. Hydraulic oil temperature and pressure sensors (such as PT100 and HDA3800) are arranged at key nodes of the system (such as the main pump outlet and motor inlet and outlet) to monitor the system status in real time and feed the signals back to the electronic control unit, thus forming an intelligent hydraulic transmission and execution system controlled by the electronic control unit, as detailed in Table 1.

[0032] Table 1 Main Components of Hydraulic Transmission and Actuation Unit

[0033] Variable displacement piston pump Driven directly by an engine, it converts mechanical energy into hydraulic energy. Its displacement can be adjusted by an electronic control unit via a proportional solenoid valve to control the output flow. ECU controls via PWM signal Left track motor The left track is driven by an electronic control unit that can adjust its displacement according to the load to optimize efficiency. ECU controls via PWM signal Right track motor The right track is driven by an electronic control unit that can adjust its displacement according to the load to optimize efficiency. ECU controls via PWM signal proportional valve group The integrated multi-channel high-frequency response proportional valve receives commands from the electronic control unit to precisely control the flow and pressure of hydraulic oil to the left and right motors, achieving stepless speed regulation and steering. ECU controls via current signal Hydraulic oil temperature sensor The temperature of the hydraulic system's return oil circuit is monitored in real time, and the signal is transmitted to the electronic control unit. Analog signal input to ECU pressure sensor Installed at the main pump outlet and the inlet and outlet of the left and right motors respectively, to monitor system pressure. Analog signal input to ECU

[0034] In this embodiment, the electronic control unit uses multiple CAN bus interfaces to exchange data at high speed with the engine controller, hydraulic valve group controller and human-machine interaction unit, thereby ensuring the synchronization and real-time performance of control commands. Multiple ADC channels are used to accurately acquire various analog sensor signals (such as pressure, temperature and angle). Multiple PWM pulse width modulation output channels are used to drive actuators such as proportional valves and cooling fans. The memory (Flash) is used to store system parameters, fault code history records and intermediate calculation data.

[0035] In this embodiment, the sensing and monitoring unit is arranged at key nodes of the chassis. This unit detects the actual rotation speed of the tracks on both sides in real time through digital pulse speed sensors near the left and right track drive wheels, monitors the lateral and longitudinal tilt angles of the chassis through tilt sensors installed at the center of the chassis frame, converts the driver's forward, backward and steering intentions into electrical signals through joystick sensors integrated under the cab control panel, and receives engine speed CAN messages forwarded by the engine ECU. Combined with the analog signals collected by the oil temperature sensor installed in the hydraulic return oil circuit, the pressure sensors at the main pump outlet and motor inlet and outlet, and the temperature sensor arranged in front of the radiator, a multi-dimensional real-time operating parameter set covering power, transmission, attitude and environment is formed. All of these collected data are transmitted to the electronic control unit at high speed, as detailed in Table 2.

[0036] Table 2 Main Components of Hydraulic Transmission and Actuation Unit

[0037] Sensor type Installation location / purpose Speed ​​sensor Near the left and right track drive wheels, used to detect the actual rotational speed of the left and right tracks. Tilt sensor Installed at the center of the chassis frame, it is used to detect the lateral and longitudinal tilt angles of the machine body. joystick sensor Installed under the control panel in the driver's cab, it converts the driver's forward / reverse and steering intentions into electrical signals. Engine speed sensor At the engine flywheel end, the signal is forwarded to the electronic control unit via the engine ECU and CAN bus. pressure sensor Installed at the main pump outlet and the inlet and outlet of the left and right motors to monitor system pressure. Oil temperature sensor The temperature of the hydraulic system's return oil circuit is monitored in real time, and the signal is transmitted to the electronic control unit. Temperature sensor Installed in front of the radiator to monitor ambient temperature.

[0038] In this embodiment, the human-machine interface unit is connected to the electronic control unit via a CAN bus. The touch screen is installed on the dashboard to the right of the driver. It is used not only for users to manually select operating modes such as high-efficiency transportation mode, high-torque operation mode, and fine-tuning mode, and set operating parameters such as the sensitivity of the fine-tuning mode, but also to display in real time the raw system status information collected by the sensing and monitoring unit, including engine speed, hydraulic oil temperature, and current vehicle speed, as well as in-depth efficiency indicators such as hourly fuel consumption and cumulative working area calculated by the electronic control unit. In addition, it is responsible for receiving the user's setting instructions and sending them to the electronic control unit, and at the same time receiving and displaying the fault alarm codes and maintenance reminder information issued by the electronic control unit.

[0039] In this embodiment, the thermal management unit consists of a plate-fin hydraulic oil radiator, a cooling fan driven by a brushless DC motor, and a dedicated drive controller. The electronic control unit continuously receives hydraulic oil temperature signals from the sensing and monitoring unit, and combines the actual power loss of the current hydraulic system (calculated from pressure and flow) and the selected operating mode (e.g., a high-torque operating mode generates more heat) as input parameters. The heat dissipation demand is calculated in real time through a PID control algorithm, and then a PWM pulse width modulation signal is generated to dynamically adjust the speed of the cooling fan. This achieves the matching of heat dissipation capacity with the actual operating conditions of the system, thereby ensuring that the hydraulic oil temperature is always stable within the optimal operating range (e.g., 65±3℃), extending the system life.

[0040] This invention provides an embodiment to illustrate the control strategy of this invention:

[0041] The adaptive power distribution strategy for the operation mode of this invention is explained as follows: The electronic control unit has three-dimensional pulse spectrum maps (MAP maps) of three modes pre-stored inside. These MAP maps were obtained through previous bench tests and field calibration.

[0042] In high-efficiency transportation mode, the electronic control unit queries the mode MAP and sets the engine target speed in the economic zone of 1500-1800 rpm, while limiting the main pressure of the hydraulic system to below 20 MPa. At this time, the engine noise is significantly reduced, and the fuel consumption for field transfer is reduced by about 15% compared with traditional fixed throttle operation.

[0043] In high-torque operation mode, the electronic control unit increases the engine target speed to near the rated power point of 2200 rpm, and the upper limit of hydraulic system pressure is relaxed to 28 MPa. When the plow encounters hard soil, the system can provide sufficient traction to overcome resistance and thus avoid stalling.

[0044] In fine-tuning mode, the electronic control unit locks the engine speed at 1600 rpm. All the driver's control lever signals are first filtered to eliminate hand tremors, and then processed by an adjustable dead zone (default ±5%). The processed tiny signals are mapped to a 0.1-0.5A micro current control signal for the proportional valve, thus achieving "centimeter-level" movement of the tracks. This is very suitable for use when approaching crops in greenhouses, eliminating the phenomenon of "skipping and stopping".

[0045] The anti-slip control strategy of this invention is explained as follows: The electronic control unit calculates the speed difference between the left and right tracks in real time. Safety threshold It is not a fixed value, but rather based on the lateral tilt angle provided by the tilt sensor. Dynamic calculation: (k is the calibration coefficient). On a slope, the allowable speed difference threshold decreases, making the system more sensitive to slippage to prevent sideslip. The electronic control unit immediately sends a command to the proportional valve on the slipping side, instantly reducing its valve opening (reducing pressure), while slightly increasing the power output on the non-slipping side to compensate for the total traction force.

[0046] The thermal management strategy of the present invention will be explained as follows:

[0047] In the traditional method, when the oil temperature reaches 75℃, the temperature control switch closes and the fan runs at 100% full speed; when the oil temperature drops to 65℃, the fan turns off.

[0048] The electronic control unit of this invention calculates the target fan speed according to the PID algorithm. The algorithm input is: the current oil temperature ( ), target oil temperature ( The default setting is 65℃, and the oil temperature change rate (dT / dt) is output as the PWM duty cycle. The formula is ,in, = 65℃- , This is the current temperature deviation. This represents the temperature deviation from the previous sampling period. This represents the temperature deviation from the sampling period two weeks prior. , , These are the pre-tuned control parameters for the hydraulic cooling system.

[0049] When the oil temperature rises to 60°C, the electronic control unit begins to slowly increase the fan speed to 30%. When the oil temperature rises to 65°C, the fan speed increases to 60%, thus achieving "on-demand cooling," avoiding frequent start-stop and high-speed operation of the fan, significantly reducing heat dissipation energy consumption, and keeping the oil temperature stable within ±3°C.

[0050] For the above strategy, the electronic control unit of this invention continuously monitors all sensors and actuators. Once an anomaly is detected, such as a Level 1 fault (e.g., a pressure sensor signal drift), the electronic control unit records a fault code and displays a notification on the human-machine interface. For a Level 2 fault (e.g., a single-channel speed sensor failure), the electronic control unit records a fault code, issues an alarm, and initiates a degraded control strategy: disabling the anti-slip function, locking the differential, and fixing the hydraulic pump flow rate; the vehicle can still travel at a slow speed under these conditions. For a Level 3 fault (e.g., complete loss of communication between the electronic control unit and the engine controller), the electronic control unit triggers the highest-level alarm and executes a "limp home" maneuver, controlling the engine idle speed and attempting to drive the tracks with the lowest preset fixed hydraulic flow rate to ensure the user can drive the vehicle away from the danger zone.

[0051] Please see Figure 1 Furthermore, the workflow of this invention will be described as follows:

[0052] After the driver starts the vehicle, he selects the "high-efficiency transportation mode" through the touch interface of the human-machine interaction unit in the cab. The mode selection command is sent to the electronic control unit via the CAN bus, and the electronic control unit then calls the preset control parameters for this mode.

[0053] During the field transfer process, the electronic control unit continuously receives engine speed, vehicle speed and load signals from the sensing and monitoring unit, and executes the "high-efficiency transportation mode" strategy. It generates the first control command and sends it to the engine controller through the CAN bus to stabilize the engine speed in the economic speed range of 1600 rpm. At the same time, it generates the second control command to control the proportional valve in the hydraulic transmission and actuation unit to limit the system working pressure to a low level, thereby achieving smooth high-speed driving of the vehicle and significantly reducing fuel consumption.

[0054] Once the vehicle arrives at the work site, the driver switches the work mode to "high torque work mode" via the human-machine interface unit. The electronic control unit immediately responds to this command, changes the control strategy, and generates a new first control command set to increase the engine target speed to near the rated power point of 2200 rpm. At the same time, it releases the hydraulic system pressure limit and allows it to respond to higher load demands, providing maximum traction for the plow to enter the soil.

[0055] During deep-plowing operations, when the vehicle encounters a slippery slope, the tilt sensor and left and right track speed sensors in the sensing and monitoring unit detect the vehicle's tilt posture and the abnormal increase in the speed of one track in real time. The anti-slip control strategy in the electronic control unit is triggered, and a second control command is generated instantly to adjust the hydraulic proportional valve, reduce the driving pressure of the slipping track, and provide power compensation to the other track, automatically correcting the driving trajectory to ensure the safety of slope operations.

[0056] In response to the rise in hydraulic oil temperature caused by continuous heavy-duty operations, the electronic control unit continuously receives signals from the hydraulic oil temperature sensor. When the oil temperature rises to 58°C, it actively intervenes, calculates the required heat dissipation based on the PID algorithm, and generates a third control instruction set. It then controls the cooling fan in the thermal management unit to run at 45% speed in advance using PWM, thereby accurately stabilizing the oil temperature in the optimal working range and preventing the system from overheating.

[0057] When the vehicle returns to the hangar after the operation is completed and needs to be parked, the driver switches to the "fine-tuning mode" through the human-machine interface unit. The electronic control unit then locks the engine speed at 1600 rpm and takes over the control lever signal. It performs low-pass filtering and dead-zone compensation to eliminate vibration. Finally, the processed micro-command signal is mapped to the precise current control of the proportional valve to achieve extremely low-speed, smooth and precise movement of the tracks and complete the safe parking.

[0058] Throughout the entire work cycle, the electronic control unit synchronously performs data recording, continuously monitors and calculates cumulative fuel consumption and work area data, stores this efficiency data in non-volatile memory, and provides the driver with a fuel consumption report and efficiency analysis of the work through the human-machine interaction unit after the task is completed, providing data support for users to perform cost accounting and efficiency optimization.

[0059] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A power chassis system for a small tracked tractor, characterized in that, Including: A power source unit is used to convert chemical energy into mechanical energy and provide raw power output; The hydraulic transmission and actuator unit has its input end coupled to the output end of the power source unit, which is used to convert the original power into hydraulic energy and drive the left and right tracks to move independently. The electronic control unit serves as the core controller of the system. The sensing and monitoring unit is located at key nodes of the chassis to collect operating parameters in real time, including engine speed, hydraulic system pressure, actual track speed, body attitude and operating commands, and transmit the collected data to the electronic control unit. The electronic control unit is used to receive multiple operating parameters from the sensing and monitoring unit, and based on the preset control strategy and the received parameters, generates a first control command to adjust the output power of the power source unit, and generates a second control command to independently control the flow and pressure of the hydraulic components in the hydraulic transmission and execution unit used to drive the left and right tracks. The control strategy includes at least one adaptive power distribution strategy based on the operating mode, which enables the electronic control unit to adjust the matching relationship between the target engine speed and the target hydraulic system pressure according to the selected operating mode. The electronic control unit also includes an anti-slip control strategy: by comparing the actual speed difference between the left and right tracks in real time, and determining that slippage occurs when the speed difference exceeds the safety threshold calculated by the current body attitude information provided by the tilt sensor in the sensing and monitoring unit, the hydraulic drive pressure of the slipping track is instantly reduced and the power compensation is applied to the non-slipping track through the second control command to maintain the total traction force. The anti-slip control strategy can work in conjunction with the power distribution strategy based on the working mode. In the high-torque working mode, the electronic control unit uses a first calibration parameter to calculate the slip judgment threshold to allow for a difference in track speed. In the high-efficiency transport mode, the electronic control unit uses a second calibration parameter to calculate the slip judgment threshold to minimize power loss and track wear.

2. The power chassis system for a small tracked tractor according to claim 1, characterized in that: The adaptive power distribution strategy based on operating modes includes multiple operating modes, including high-efficiency transport mode, high-torque operating mode, and fine-tuning mode. When high-efficiency transport mode is selected, the electronic control unit prioritizes reducing the engine target speed and controls the hydraulic system to maintain a low base pressure to minimize fuel consumption. When high-torque operating mode is selected, the electronic control unit prioritizes increasing the engine target speed and allows the hydraulic system to respond to higher pressure demands to maximize traction output. When fine-tuning mode is selected, the electronic control unit controls the engine to stabilize at an economical fixed speed and makes minor adjustments to the hydraulic unit.

3. The power chassis system for a small tracked tractor according to claim 1, characterized in that: The system also includes an intelligent thermal management unit, which includes a hydraulic oil radiator, a cooling fan and its drive controller. The electronic control unit continuously receives hydraulic oil temperature signals and calculates the heat dissipation requirements based on the current oil temperature, the actual power loss of the hydraulic system and the selected operating mode. It then generates a third control command to control the speed of the cooling fan in PWM pulse width modulation mode.

4. The power chassis system for a small tracked tractor according to claim 1, characterized in that, The control logic of the electronic control unit in fine-tuning mode includes: receiving a micro-motion command signal from the operating lever, performing low-pass filtering and dead-zone compensation on the signal, and then mapping the processed command signal into a small current control signal for the proportional valve in the hydraulic transmission and actuation unit.

5. The power chassis system for a small tracked tractor according to claim 1, characterized in that: The system also includes a human-machine interaction unit, which is connected in communication with the electronic control unit. The human-machine interaction unit is used to allow users to select operating modes, set operating parameters, and display in real time the system status information collected by the sensing and monitoring unit and the efficiency indicators calculated by the electronic control unit.

6. The power chassis system for a small tracked tractor according to claim 5, characterized in that: The electronic control unit continuously calculates and records the fuel consumption per unit area or the workload per unit time, and provides users with work efficiency reports and maintenance reminders based on historical data through the human-machine interaction unit.

7. The power chassis system for a small tracked tractor according to claim 1, characterized in that, The control strategy of the electronic control unit also includes a power pre-allocation function based on load prediction: the electronic control unit can learn and memorize the driver's operating habits in repetitive work sections or repetitive actions, and increase the speed of the power source unit in advance when it predicts that a high load condition will occur.

8. A small tracked tractor power chassis system according to any one of claims 1-7, characterized in that: When the sensing and monitoring unit detects any abnormality in any critical parameter or failure of a component, the electronic control unit will automatically degrade the control strategy according to the fault level. This can be achieved by limiting the maximum engine speed, fixing the hydraulic flow, or locking the differential, so that the chassis system can move to a safe area at the lowest functional level.

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