Topological Structure and Operation Mode of an Intelligent Driving Electric Tractor Assisted by Supercapacitors

Abstract

The present invention relates to a topological structure and operation mode of an intelligent driving electric tractor assisted by a super capacitor, including a power battery, a super capacitor, a traction motor, a PTO motor, a steering assist pump, a lidar, a binocular camera, an acceleration sensor, a speed sensor, an industrial control computer, and a vehicle controller; The intelligent driving electric tractor is driven by a traction motor, and the traction motor and the PTO motor are controlled by the vehicle controller to meet the power requirements needed in different working modes; The lidar, the binocular camera, the industrial control computer, and the speed sensor form an intelligent perception system, and the vehicle controller controls the power output of the traction motor, the power output of the PTO motor, and controls the oil pressure of the steering assist pump to control the steering wheel angle according to the signals of the intelligent perception system, improving the operation accuracy and efficiency of the tractor, reducing the labor intensity of the tractor driver, and providing driving energy for the tractor through the power battery and the super capacitor, with no emissions during operation, protecting the environment.

Description

Technical Field

[0001] The present invention relates to the technical field of electric tractors, and particularly relates to a topological structure and operation mode of an intelligent driving electric tractor assisted by a super capacitor. Background Art

[0002] With the rapid development of the economy, the degree of mechanization is getting higher and higher. The growth rates of the transportation industry, agricultural machinery, and construction machinery have increased rapidly, and they have become the industries with the largest energy consumption and the fastest growth rate in the world. On the one hand, the increasing degree of mechanization promotes economic development and facilitates people's lives. On the other hand, it also brings serious environmental pollution. Exhaust emissions also contribute to the aggravation of the greenhouse effect to a certain extent, having a non-negligible negative impact on people's lives and health. Currently, traditional tractors, as the main mechanical equipment for agricultural production, undertake the tasks of farmland construction and agricultural production, and the inventory is increasing year by year. At the same time, it also significantly increases the consumption of fuel. In order to alleviate the contradiction among energy, the environment, and the rapid economic development, it is of great significance to carry out research on electric tractor technology and develop electric tractor products.

[0003] The working conditions of electric tractors in the field are complex, and various different operation modes need to be executed. Different operation modes put forward different ranges of requirements for the motor power. Therefore, when the power battery supplies energy, it often needs to discharge with different magnitudes of current, resulting in a shortened cycle service life of the power battery.

[0004] With the transformation of China's agriculture from traditional extensive production to a refined operation mode, new requirements for the intelligence of agricultural machinery have been put forward in agricultural production. The refined operation of agricultural machinery in agricultural production is based on reasonable driving control. Currently, the driving of tractors mainly relies on the operation of drivers. During the process of driving a tractor, the driver not only has to be responsible for the driving of the tractor but also has to take into account many information such as the surface state and the growth of crops, making it difficult to ensure the operation accuracy and operation efficiency. Summary of the Invention

[0005] The present invention proposes a topological structure and operation mode of an intelligent driving electric tractor assisted by a super capacitor, including a power battery, a super capacitor, a first DC / DC converter, a second DC / DC converter, a traction motor, a low-voltage storage battery, a steering assist pump, a binocular camera, a lidar, an industrial control computer, a central drive, rear wheels, an acceleration sensor, a speed sensor, a vehicle controller, a PTO motor, a transmission, and a DC / AC converter; the connection methods include electrical connection, CAN bus connection, Ethernet connection, UDP connection, and mechanical connection; the vehicle controller controls the output of the required power of the traction motor and the PTO motor according to the intelligent perception system and the driver input signal.

[0006] The power battery, super capacitor, second DC / DC converter, low-voltage battery, lidar, binocular camera, industrial computer, vehicle controller, speed sensor, DC / AC converter, traction motor, and PTO motor are electrically connected; the power battery and super capacitor input the converted high-voltage three-phase power into the traction motor and PTO motor through the DC / AC converter, so that the traction motor and PTO motor output power; the power battery and super capacitor input the converted low-voltage direct current into the low-voltage battery through the second DC / DC converter; the low-voltage battery provides low-voltage direct current for the lidar, binocular camera, industrial computer, vehicle controller, and speed sensor.

[0007] The vehicle controller is connected to the speed sensor, transmission, steering assist pump, PTO motor, traction motor, DC / AC converter, power battery, super capacitor, first DC / DC converter, second DC / DC converter, and low-voltage battery through the CAN bus; the lidar, binocular camera, industrial computer, and speed sensor form an intelligent perception system. The vehicle controller issues corresponding control commands according to the signals of the intelligent perception system, the accelerator pedal signal, and the brake pedal signal input by the driver, and performs start, acceleration, deceleration, braking control, etc. on the traction motor and PTO motor; at the same time, the vehicle controller controls the steering assist pump to achieve intelligent driving steering or provide steering assistance for the driver.

[0008] The lidar and the industrial computer are connected by Ethernet; the industrial computer and the vehicle controller are connected by UDP; the traction motor is mechanically connected to the transmission, steering assist pump, central drive, and rear wheels; the traction motor delivers the output power to the transmission, steering assist pump, central drive, and rear wheels through mechanical connection.

[0009] The super capacitor is connected in series with the first DC / DC converter and then in parallel with the power battery. The voltage of the super capacitor is controlled to be the same as that of the power battery by detecting the voltage of the power battery. In the case of moderate power requirements such as field transportation and rotary tillage, the power battery supplies power alone and the super capacitor does not participate in the work; in the case of large power requirements such as plowing and subsoiling, the power output of the power battery and super capacitor is distributed according to the power battery SOC, super capacitor voltage, and required power.

[0010] The vehicle controller controls the speed of the PTO motor, and the PTO motor provides the PTO power output of the tractor. The PTO motor has two working modes under the control of the vehicle controller: the first working mode is the PTO motor speed synchronization with the tractor driving speed mode. In this working mode, the speed of the PTO motor of the electric tractor can synchronously follow the tractor driving speed, providing a reasonable, reliable and precise control spacing method for operations such as seeding and spraying of the electric tractor. The second working mode is the PTO motor fixed speed mode. In this working mode, the PTO motor of the electric tractor can output a fixed speed arbitrarily within a certain range to match different agricultural implements.

[0011] The lidar and the binocular camera extract and collect the information of the surrounding roads or fields during the driving process of the tractor in real time, and send the collected road or field situation information to the industrial control computer. The industrial control computer plans the operation trajectory of the tractor according to the received road or field situation information, calculates the required steering wheel angle according to the operation trajectory, and transmits the steering wheel angle information to the vehicle controller. The vehicle controller controls the traction motor responsible for the tractor's progress and the PTO motor responsible for agricultural operations according to the operation trajectory and the accelerator pedal signal and brake pedal signal input by the driver. At the same time, when the tractor reaches the corresponding corner position in the operation trajectory, the vehicle controller calculates the required pressure of the steering assist pump according to the steering wheel angle information and controls the steering assist pump to steer.

[0012] The advantages and positive effects of the present invention are as follows: The present invention uses electric energy to replace petroleum raw materials, provides driving energy for the tractor through power batteries, avoids providing power in the traditional fuel way, has no emissions during operation, and protects the environment; by using an intelligent perception system, the operation accuracy and efficiency of the tractor are improved, and the labor intensity of the tractor driver is reduced; due to the advantages of high power density, short charge and discharge time, long cycle life and wide working temperature range of the super capacitor, the super capacitor is used as an auxiliary energy device to reduce the number of large current discharges of the power battery under high power conditions and extend the cycle service life of the battery. Brief Description of the Drawings

[0013] Figure 1 It is a topological structure diagram of the intelligent driving electric tractor assisted by a super capacitor of the present invention.

[0014] Figure 2 It is a schematic diagram of the PTO motor control process.

[0015] Figure 3 It is a schematic diagram of the intelligent perception system working process.

[0016] Figure 4 It is a schematic diagram of the working modes of the power battery and the super capacitor.

[0017] As shown in the figure: 1. Power battery, 2. First DC / DC converter, 3. Second DC / DC converter, 4. Super capacitor, 5. Low-voltage battery, 6. Steering assist pump, 7. Binocular camera, 8. Lidar, 9. Industrial control computer, 10. Central transmission device, 11. Rear wheel, 12. Acceleration sensor, 13. Speed sensor, 14. Vehicle controller, 15. PTO motor, 16. Transmission, 17. Traction motor, 18. DC / AC converter. Specific implementation mode

[0018] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0019] Please refer to Figure 1 , a topology structure of an intelligent driving electric tractor assisted by a super capacitor according to the present invention, includes a power battery 1, a first DC / DC converter 2, a second DC / DC converter 3, a super capacitor 4, a low-voltage battery 5, a steering assist pump 6, a binocular camera 7, a lidar 8, an industrial control computer 9, a central transmission device 10, a rear wheel 11, an acceleration sensor 12, a speed sensor 13, a vehicle controller 14, a PTO motor 15, a transmission 16, a traction motor 17, and a DC / AC converter 18; the connection methods include electrical connection, CAN bus connection, Ethernet connection, UDP connection, and mechanical connection; the vehicle controller controls the output of the traction motor and the PTO motor according to the intelligent perception system and the driver input signal to obtain the required power.

[0020] The super capacitor is connected in series with the first DC / DC converter and then connected in parallel with the power battery. The output terminals of the first DC / DC converter and the power battery are both electrically connected to the input terminal of the DC / AC converter. The output terminal of the DC / AC converter is respectively electrically connected to the traction motor and the PTO motor. The power battery and the super capacitor input the converted high-voltage three-phase electricity into the traction motor and the PTO motor through the DC / AC converter, so that the traction motor and the PTO motor output power; the output terminals of the first DC / DC converter and the output terminal of the power battery are also both electrically connected to the input terminal of the second DC / DC converter. The output terminal of the second DC / DC converter is electrically connected to the low-voltage battery. The power battery and the super capacitor input the converted low-voltage direct current into the low-voltage battery through the second DC / DC converter to charge the low-voltage battery; the low-voltage battery is respectively electrically connected to the lidar, the binocular camera, the industrial control computer, the vehicle controller, the acceleration sensor, and the speed sensor to provide low-voltage direct current for the lidar, the binocular camera, the industrial control computer, the vehicle controller, the acceleration sensor, and the speed sensor.

[0021] The described vehicle controller is respectively connected to the acceleration sensor, speed sensor, transmission, steering assist pump, PTO motor, traction motor, DC / AC converter, power battery, super capacitor, first DC / DC converter, second DC / DC converter, and low-voltage battery through the CAN bus. The binocular camera is connected to the industrial computer through the CAN bus. The lidar is connected to the industrial computer through Ethernet. The industrial computer is connected to the vehicle controller through UDP. The lidar, binocular camera, industrial computer, and speed sensor form an intelligent perception system. The vehicle controller issues corresponding control commands according to the signals of the intelligent perception system and the accelerator pedal signal and brake pedal signal input by the driver, and performs start, acceleration, deceleration, braking control, etc. on the traction motor and PTO motor. At the same time, the vehicle controller controls the steering assist pump to achieve intelligent driving steering or provide steering assistance for the driver.

[0022] The binocular camera is connected to the industrial computer through the CAN bus. The binocular camera is used to collect information about the surrounding roads or fields. The lidar is connected to the industrial computer through Ethernet. The lidar is used to survey the distance between the surrounding obstacles and the tractor. The industrial computer is connected to the vehicle controller through UDP. The output end of the traction motor is mechanically connected to the transmission. The output end of the transmission is respectively mechanically connected to the steering assist pump and the central transmission device installed on the rear axle. The traction motor transmits the output power to the transmission through mechanical connection, and the transmission then transmits the output power to the central transmission device and the steering assist pump respectively. The central transmission is used to drive the rear wheels to rotate to achieve the advancement of the tractor, and the steering assist pump is used to achieve the steering of the tractor. The foregoing mechanical connection method is prior art and will not be elaborated.

[0023] Please refer to Figure 2, the PTO motor has two working modes under the control of the vehicle controller: The first working mode is the PTO motor speed synchronization with the tractor driving speed mode. This working mode can achieve the speed of the PTO motor of the electric tractor synchronously following the driving speed of the tractor, providing a reasonable, reliable and precise control spacing method for operations such as seeding and spraying of the electric tractor. The specific execution process of this working mode is as follows: After the driver manually selects the PTO motor speed synchronization with the tractor driving speed mode, the speed sensor real-time collects the tractor driving speed and uploads it to the vehicle controller. The vehicle controller calculates the required speed n2 of the PTO motor according to the received speed signal, and then the vehicle controller sends the speed signal n2 to the PTO motor, and the PTO motor runs at the required speed n2; The second working mode is the fixed speed mode of the PTO motor. This working mode can achieve the PTO motor of the electric tractor outputting at any fixed speed within a certain range to match different agricultural implements. The specific execution process of this working mode is as follows: After the driver manually selects the fixed speed mode of the PTO motor and inputs the required speed n1, the vehicle controller sends the speed signal n1 to the PTO motor after receiving the input instruction, and the PTO motor runs at the fixed speed n1.

[0024] Please refer to Figure 3 , the working method of the intelligent perception system is as follows: The lidar and the binocular camera real-time extract and collect the information of the surrounding roads or fields during the tractor's driving, and send the collected information of the roads or fields to the industrial control computer; The industrial control computer plans the tractor operation trajectory according to the received information of the roads or fields, calculates the required steering wheel angle according to the operation trajectory, and at the same time transmits the tractor operation trajectory and steering wheel angle information to the vehicle controller; The vehicle controller outputs to control the traction motor responsible for the tractor's progress and the PTO motor responsible for the agricultural implement operation according to the operation trajectory and the accelerator pedal signal and brake pedal signal input by the driver. At the same time, when the tractor reaches the corresponding corner position in the operation trajectory, the vehicle controller calculates the required pressure of the steering assist pump according to the steering wheel angle information and controls the steering assist pump to act to push the front wheels to turn.

[0025] Please refer to Figure 4 , during the operation of the intelligent driving electric tractor, the working mode of the power battery and the super capacitor is as follows: The vehicle controller controls the energy supply of the power battery and the super capacitor according to the required power, the SOC value of the power battery and the voltage value of the super capacitor. Specifically: The vehicle controller reads the current power of the traction motor and the PTO motor and P 1 , the current speed v of the tractor 1 , the current acceleration a of the tractor 1 , and obtains the expected speed v of the tractor at the next moment through the intelligent driving motion planning algorithm 2, and the expected acceleration a 2 ; The vehicle controller calculates: the current acceleration resistance power The acceleration resistance power at the next moment is where δ is the conversion coefficient of the rotating mass of the tractor, m is the mass of the tractor (kg), and the change value of the acceleration resistance power ΔP = P j1 -P j2 , and the sum of the expected powers of the traction motor and the PTO motor at the next moment P 2 = P 1 + ΔP. Set the power value P in the vehicle controller min (used to determine whether the tractor is a high-power load or a low-power load at this time), the SOC value of the power battery 1 value (to avoid over-discharge when the SOC value of the power battery is too low), and the voltage value V of the super capacitor 1 (to avoid low energy efficiency when the voltage of the super capacitor is too low). When the SOC value of the power battery is lower than SOC 1 , the electric tractor interrupts the current operation and drives to the charging place to charge the power battery in time; when the SOC value of the power battery is higher than SOC 1 , and the required expected power sum P 2 is greater than P min : If the voltage value of the super capacitor is greater than V 1 , the power battery and the super capacitor supply energy simultaneously, and the power battery outputs the average power, and the super capacitor outputs the peak power; if the voltage value of the super capacitor is less than V 1 , the electric tractor interrupts the current operation and drives to the charging place to charge the power battery and the super capacitor in time. At this time, the super capacitor is preferentially discharged to protect the power battery; when the SOC value of the power battery is higher than SOC 1 , and the required expected power sum P 2 is less than P min : The power battery supplies energy alone, and the super capacitor does not participate in energy supply.

[0026] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. The protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope of the present invention, according to the solution and concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. Operating mode of an intelligent driving electric tractor assisted by supercapacitors, Characterized in that The topological structure adopted by the electric tractor includes a power battery (1), a first DC / DC converter (2), a second DC / DC converter (3), a supercapacitor (4), a low-voltage battery (5), a steering assist pump (6), a central drive (10), rear wheels (11), a vehicle controller (14), a PTO motor (15), a transmission (16), a traction motor (17), a DC / AC converter (18) and an intelligent perception system; the supercapacitor is connected in parallel with the power battery through the first DC / DC converter and is respectively electrically connected to the input end of the second DC / DC converter and the input end of the DC / AC converter, the output end of the second DC / DC converter is electrically connected to the low-voltage battery, and the output end of the DC / AC converter is respectively electrically connected to the traction motor and the PTO motor; the output end of the traction motor is mechanically connected to the input end of the transmission, and the output end of the transmission is mechanically connected to the steering assist pump and the central drive device; the intelligent perception system includes a binocular camera (7), a lidar (8), an industrial computer (9), an acceleration sensor (12), a speed sensor (13), the low-voltage battery is respectively electrically connected to the binocular camera, the lidar, the industrial computer, the vehicle controller, the acceleration sensor, and the speed sensor, the binocular camera is connected to the industrial computer through a CAN bus, the lidar is connected to the industrial computer through an Ethernet, and the industrial computer and the vehicle controller perform data communication through a UDP communication protocol; the vehicle controller is respectively connected to the acceleration sensor, the speed sensor, the transmission, the steering assist pump, the traction motor, the PTO motor, the first DC / DC converter, the second DC / DC converter, the DC / AC converter, the power battery, and the low-voltage battery through a CAN bus; During the operation of the electric tractor, the working modes of the power battery and the supercapacitor are as follows: The vehicle controller reads the current power sum of the traction motor and the PTO motor , the current speed of the tractor , the current acceleration of the tractor , and calculates the expected speed and the expected acceleration of the tractor at the next moment through the intelligent driving motion planning algorithm; The vehicle controller calculates: the current acceleration resistance power , and the acceleration resistance power at the next moment is , where is the conversion coefficient of the rotating mass of the tractor, is the mass of the tractor (kg), the change value of the acceleration resistance power , and the expected power sum of the traction motor and the PTO motor at the next moment ; Set the power value , the value of the power battery and the supercapacitor voltage value in the vehicle controller When the state of charge (SOC) of the power battery is lower than , interrupt the current operation and drive to the charging location to charge the power battery in a timely manner; When the SOC value of the power battery is higher than and the required desired power and is greater than : If the supercapacitor voltage value is greater than , both the power battery and the supercapacitor supply energy simultaneously, and the power battery outputs the average power while the supercapacitor outputs the peak power; if the supercapacitor voltage value is less than , interrupt the current operation and drive to the charging location to charge the power battery and the supercapacitor in time. At this time, give priority to discharging the supercapacitor to protect the power battery; When the SOC value of the power battery is higher than and the required desired power and is less than : The power battery supplies energy alone, and the supercapacitor does not participate in energy supply.

2. The operating mode of the intelligent driving electric tractor assisted by supercapacitors according to claim 1, Characterized in that The driver can manually select the working mode of the PTO motor: If the driver manually selects the fixed speed mode of the PTO motor, the required speed n1 of the PTO motor needs to be input. After receiving the input command, the vehicle controller sends an n1 speed signal to the PTO motor, and the PTO motor operates at a fixed speed n1; If the driver manually selects the speed synchronization tractor driving speed mode of the PTO motor, the speed sensor collects the driving speed of the tractor in real time and uploads it to the vehicle controller. The vehicle controller calculates the required speed n2 of the PTO motor according to the received speed signal, and then the vehicle controller sends an n2 speed signal to the PTO motor, and the PTO motor operates at a speed n2.

3. The operating mode of the intelligent driving electric tractor assisted by supercapacitors according to claim 1, Characterized in that The working mode of the intelligent perception system is as follows: The lidar and the binocular camera extract and collect the information of the surrounding roads or fields during the driving process of the tractor in real time, and send the collected information of the roads or fields to the industrial control computer; The industrial control computer plans the operation trajectory of the tractor according to the received information of the roads or fields, calculates the required steering wheel angle according to the operation trajectory, and at the same time transmits the operation trajectory and steering wheel angle information of the tractor to the vehicle controller; The vehicle controller outputs to control the traction motor and the PTO motor according to the operation trajectory and the accelerator pedal signal and the brake pedal signal input by the driver. At the same time, when the tractor reaches the corresponding corner position in the operation trajectory, the vehicle controller calculates the required pressure of the steering assist pump according to the steering wheel angle information and controls the steering assist pump to actuate to push the front wheels to steer.

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