Distributed driving crane chassis device based on hybrid power system and control method thereof

Abstract

The invention discloses a distributed driving crane chassis device based on a hybrid power system and a control method of the distributed driving crane chassis device, and belongs to the technical field of engineering machinery chassis. The device comprises a range extender or a parallel hybrid power system, a power battery, a distributed electric drive axle, a vehicle control unit (VCU) and a steering-by-wire and brake-by-wire system. The range extender is formed by connecting an engine and a generator in series. According to the distributed electric drive axle, wheel-side double motors are adopted to independently drive wheels on the corresponding sides, torque vector distribution and braking energy recovery are achieved through a motor controller, and a vehicle control unit (VCU) is switched among a pure electric mode, a range extending mode and a strong hybrid mode according to the vehicle speed, the required torque, the battery SOC and the road gradient and coordinates energy management. According to the invention, a transfer case, a transmission shaft and a hydraulic driving element are omitted, and the system has the advantages of small arrangement space, fast response, high control precision, low energy consumption, low emission, capability of realizing in-situ turning and the like, and is suitable for small and medium tonnage and super tonnage all-terrain cranes.

Description

Technical Field

[0001] This invention belongs to the field of engineering machinery chassis technology, and particularly relates to a distributed drive crane chassis device based on a hybrid power system and its control method. Background Technology

[0002] With increasing global demands for energy conservation and emission reduction, the construction machinery industry is accelerating its transformation towards new energy and intelligent technologies. International manufacturers such as Liebherr, Tadano, and Putzmeister have launched hybrid cranes; domestic companies such as XCMG, Sany, and Zoomlion have also released clean energy cranes.

[0003] Existing crane chassis mostly employ centralized hydraulic drives or central electric drive axles, which generally suffer from the following shortcomings: a simple structural layout requiring a transfer case, drive shaft, and differential, resulting in large space occupation; the drive system is primarily series or parallel hybrid, leading to slow response and low control precision; the hydraulic system is inefficient, prone to leakage, and has high maintenance costs; independent control of the drive wheels is impossible, resulting in a large turning radius and poor maneuverability. Chinese patent CN119369906A discloses a multi-axle chassis electric drive system, which provides driving force to the entire vehicle when the undercarriage power or transmission capacity is insufficient, but it is still a centralized drive and the source of electricity is not clearly defined. Chinese patent CN119568115A discloses a range-extended hybrid power control method, enabling both undercarriage and overcarriage operations to have pure electric and range-extended modes, meeting the needs of long-term undercarriage travel and overcarriage operations, but the drive axle is still a centralized integrated electric drive axle. Therefore, there is an urgent need for a distributed drive crane chassis device that is compact, efficient, precisely controlled, and suitable for various tonnages. Summary of the Invention

[0004] Purpose of the invention: To address the shortcomings of existing technologies, the purpose of this invention is to provide a distributed drive crane chassis device and its control method based on a hybrid power system. Through torque vector control and independent steering of all wheels, it achieves on-the-spot turning, small turning radius, and high handling stability. Through the drive-by-wire design, it provides a hardware foundation for future autonomous driving and remote control.

[0005] Technical Solution: This invention provides a distributed drive crane chassis device based on a range-extended hybrid power system suitable for small and medium-tonnage cranes, comprising: a range extender, consisting of an engine and a generator connected in series, for outputting electrical energy; a power battery, connected in parallel with the range extender, for storing and providing electrical energy; at least two distributed electric drive axles, each axle including an axle housing, wheel-side dual motors integrated into the axle housing, a main reducer, and a motor controller, wherein the wheel-side dual motors independently drive the corresponding side wheels, and the motor controller independently controls the torque vector distribution of each wheel; and a vehicle control unit (VCU), which is communicatively connected to the range extender, the power battery, and each motor controller, for switching between pure electric mode, range-extended mode, or hybrid mode according to working conditions, and coordinating energy management; wherein there is no mechanical drive shaft between the engine and the wheels, and the range extender, the power battery, and the distributed electric drive axles are connected only by cables.

[0006] Furthermore, the wheel-side dual motors are permanent magnet synchronous motors, and each motor is equipped with a brake energy recovery module. The brake energy recovery module converts kinetic energy into electrical energy and feeds it back to the power battery when the vehicle decelerates.

[0007] Furthermore, the distributed electric drive axle also includes wheel speed sensors for real-time detection of the rotational speed of each wheel; and steering angle sensors for detection of the steering angle of each wheel. The vehicle control unit (VCU) uses the signals from the wheel speed sensors and the steering angle sensors to implement independent steering of all wheels and U-turn functionality through the motor controller.

[0008] Furthermore, the range extender is powered by a small-displacement diesel engine, with its operating point controlled by the VCU within the speed-torque range where fuel consumption is lowest.

[0009] For ultra-large tonnage cranes, the present invention also provides a distributed drive crane chassis device based on a parallel hybrid power system, comprising: an engine as the main power source; a P2 motor arranged coaxially with the engine, which can switch between motor and generator modes; a power battery electrically connected to the P2 motor and the subsequent circuit; and at least one distributed electric drive bridge. The distributed electric drive bridge includes: Axle housing; wheel-side motor, integrated into the axle housing and independently driving the corresponding wheel; A motor controller, electrically connected to the wheel-side motor, is used to independently control the torque of each wheel; The vehicle control unit (VCU) is communicatively connected to the engine, the P2 motor, the motor controller, and the power battery, and is used to switch between strong hybrid mode, pure electric mode, or range-extended charging mode. There are no hydraulic drive components between the engine, the P2 motor and the distributed electric drive axle. In strong hybrid mode, the P2 motor outputs torque together with the engine. In range-extending charging mode, the engine drives the generator to charge the power battery.

[0010] Furthermore, the P2 motor is connected to the engine via a clutch, which is engaged or disengaged by the vehicle control unit (VCU) to switch between the pure electric mode and the strong hybrid mode.

[0011] Furthermore, the distributed electric drive axle includes a torque vector control module, which, according to the instructions of the vehicle controller (VCU), increases torque to the outer wheels and decreases torque to the inner wheels when the vehicle turns, thereby reducing the turning radius.

[0012] The wheel-side motor is an external rotor permanent magnet synchronous motor with a peak torque density ≥20 N·m / kg and a peak power density ≥5 kW / kg.

[0013] Furthermore, the device also includes: The steer-by-wire system communicates with the vehicle control unit (VCU) and is used to control the steering angle of each wheel according to driver input or autonomous driving commands. The brake-by-wire system communicates with the vehicle control unit (VCU) and is used to implement motor braking via the motor controller and hydraulic braking via the friction brake according to braking requirements.

[0014] The present invention also provides a crane chassis control method, comprising the following steps: Obtain the vehicle's current speed, required torque, battery SOC, and road gradient; When the battery SOC is higher than the first threshold and the required torque is lower than the second threshold, the system enters pure electric mode and the power battery supplies power to the wheel-side motor. When the battery SOC is lower than the first threshold or the required torque is higher than the second threshold, the range extender or the engine is activated to enter the range extender mode or the strong hybrid mode. During braking, the wheel-side motor is controlled by the motor controller to recover energy and store the recovered electrical energy in the power battery. Under steering conditions, the target torque and steering angle of each wheel are calculated based on the target turning radius, and the torque and steering angle of each wheel are independently controlled by the motor controller to achieve torque vector control and all-wheel steering.

[0015] Furthermore, when the vehicle is making a U-turn, the left and right wheels are controlled to rotate in opposite directions, and the speed of each wheel is adjusted in real time according to the wheelbase and track width to achieve a zero turning radius.

[0016] Beneficial effects: Compared with the prior art, the present invention has the following advantages: (1) It eliminates the transfer case, drive shaft and hydraulic drive components, resulting in a compact structure and saving more than 20% of the layout space; (2) It effectively reduces fuel consumption and improves emission quality, while improving vehicle power, economy and handling performance; (3) The distributed hybrid powertrain has fast response, high efficiency, high control precision, optimized space layout and higher kinetic energy recovery, and can realize individual control of drive wheels. Through the vector distribution of torque and braking force, it can realize more flexible control and handling of the vehicle; (4) The drive-by-wire design provides a hardware foundation for future autonomous driving and remote control. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall layout of the distributed drive chassis of the range-extended hybrid power system of the present invention; Figure 2 A schematic diagram of the distributed drive structure of a range-extended hybrid power system; Figure 3 This is a schematic diagram of the distributed electric drive bridge structure of a range-extended hybrid power system. Figure 4 This is a schematic diagram of the overall layout of the distributed drive chassis of the parallel hybrid power system of the present invention; Figure 5 A schematic diagram of the distributed drive structure of a parallel hybrid power system; Figure 6 Here is a flowchart of the crane chassis control method; Figure 7 This is a schematic diagram of the control logic for turning around in place. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0019] Example 1: Small and medium tonnage range-extended hybrid distributed drive chassis like Figure 1 , Figure 2 , Figure 3As shown, this embodiment is applicable to small and medium tonnage cranes ranging from 25 t to 100 t. The range extender 1 consists of a 1.8 L small-displacement diesel engine 11 connected in series with a permanent magnet synchronous generator 12. There is no mechanical drive shaft between the engine 11 and the wheels. The power battery 2 is a lithium iron phosphate battery with a capacity of 80 kWh, located in the middle of the chassis. There are four distributed electric drive axles 3, each including an axle housing 31, wheel-side dual motors 32, a main reducer 33, and a motor controller 34. The wheel-side dual motors 32 are permanent magnet synchronous motors with a peak power of 80 kW and a peak torque of 1200 N·m, connected to the power battery 2 and range extender 1 via cables. The vehicle controller VCU 4 communicates with the range extender 1, power battery 2, and motor controller 34 via a CAN bus. The axle housing 31 of the distributed electric drive axle 3 is an integral cast aluminum alloy structure. The main reducer 33 is integrated in the middle of the axle housing, and the wheel-side dual motors 32 drive the wheels after reduction via planetary gears. Wheel speed sensor 35 and steering angle sensor 36 are installed on the axle housing 31. The VCU 4 realizes independent steering of all wheels according to the sensor signals, with a minimum turning radius of <5 m, and can also turn around on the spot.

[0020] When the vehicle is traveling at a constant speed of 30 km / h, VCU 4 determines that the battery SOC is greater than 60% and the required torque is less than 500 N·m, and enters pure electric mode, with the power battery 2 supplying power to the wheel-side dual motors 32. When the SOC is less than 30% or the required torque is greater than 1500 N·m, the range extender 1 is activated, entering range-extending mode. When the required torque is greater than 3000 N·m, the range extender 1 and the power battery 2 supply power simultaneously, entering hybrid mode. During braking, the motor controller 34 controls the wheel-side dual motors 32 to generate electricity, recovering energy and storing it in the power battery 2, with a recovery efficiency of 25%.

[0021] Example 2: Ultra-large tonnage parallel hybrid distributed drive chassis like Figure 4 , Figure 5 As shown, this embodiment is applicable to all-terrain cranes with a capacity of 300 tons and above. Engine 5 is a 13L diesel engine with a rated power of 480 kW. P2 motor 6 is a permanent magnet synchronous motor with a peak power of 200 kW, coaxially arranged with engine 5 via clutch 61. Power battery 7 is a lithium iron phosphate battery with a capacity of 150 kWh. There are six distributed electric drive axles 8, each including an axle housing, wheel-side motors, and a motor controller. The wheel-side motors are external rotor permanent magnet synchronous motors with a peak torque density of 25 N·m / kg and a peak power density of 6 kW / kg.

[0022] When the vehicle climbs a slope at 10 km / h, the VCU 9 determines that the required torque > 8000 N·m, controls the clutch 61 to engage, and the engine 5 and the P2 motor 6 jointly output torque, entering the strong hybrid mode; when the SOC > 50% and the required torque < 2000 N·m, the clutch 61 disengages, and the P2 motor 6 and the wheel motor are driven purely electrically; when the SOC < 20%, the engine 5 drives the P2 motor 6 to generate electricity, entering the range extender charging mode.

[0023] When making a U-turn in place, the VCU 9 calculates the target speed of each wheel based on the wheelbase L and the track width W, and controls the left wheels to rotate reversely and the right wheels to rotate forward, achieving a minimum turning radius.

[0024] Embodiment 3: Control method As Figure 6 shown, the crane chassis control method includes the following steps: S1: Obtain the vehicle speed v, the required torque Treq, the battery SOC, and the road slope θ; S2: Determine whether SOC > SOC1 and Treq < T1. If so, enter the pure electric mode; if not, enter S3; S3: Determine whether SOC < SOC2 or Treq > T2. If so, start the range extender or the engine, entering the range extender mode or the strong hybrid mode; if not, maintain the current mode; S4: During braking, control the wheel motor to generate electricity through the motor controller to recover energy; S5: During steering, calculate the target torque and angle of each wheel according to the target turning radius R to achieve torque vector control; S6: When making a U-turn in place, control the left wheels and the right wheels to rotate in opposite directions to achieve a zero turning radius.

[0025] Among them, SOC1 = 60%, SOC2 = 30%, T1 = 500 N·m, and T2 = 1500 N·m.

Claims

1. A distributed drive crane chassis device based on a range-extended hybrid power system, characterized in that, include: A range extender consists of an engine and a generator connected in series, used to output electrical energy; A power battery, connected in parallel with the range extender, is used to store and provide electrical energy; At least two distributed electric drive axles, each of the distributed electric drive axles comprising: an axle housing; wheel-side dual motors integrated into the axle housing, the wheel-side dual motors independently driving the wheels on their respective sides; a main reducer mechanically connected to the wheel-side dual motors; and a motor controller electrically connected to the wheel-side dual motors for independently controlling the torque vector distribution of each wheel. The vehicle control unit (VCU) is communicatively connected to the range extender, power battery, and motor controller. It is used to switch between pure electric mode, range extender mode, or hybrid mode according to operating conditions and to coordinate energy management. The range extender, power battery, and distributed electric drive bridge are connected by cables.

2. The apparatus according to claim 1, characterized in that, The wheel-side dual motors are permanent magnet synchronous motors, and each motor is equipped with a brake energy recovery module. The brake energy recovery module converts kinetic energy into electrical energy and feeds it back to the power battery when the vehicle decelerates.

3. The apparatus according to claim 2, characterized in that, The distributed electric drive axle also includes wheel speed sensors and steering angle sensors; the vehicle control unit (VCU) uses the signals from the wheel speed sensors and steering angle sensors to realize independent steering of all wheels and U-turn functions through the motor controller.

4. The apparatus according to claim 3, characterized in that, The range extender is powered by a small-displacement diesel engine.

5. A distributed drive crane chassis device based on a parallel hybrid power system, characterized in that, include: The engine serves as the primary power source; P2 motor, coaxially arranged with the engine, and selectively operates as a motor or generator; The power battery is electrically connected to the P2 motor and the subsequent circuitry. At least one distributed electric drive axle, the distributed electric drive axle comprising: an axle housing; a wheel-side motor integrated into the axle housing and independently driving the corresponding wheel; and a motor controller electrically connected to the wheel-side motor for independently controlling the torque of each wheel; The vehicle control unit (VCU) is communicatively connected to the engine, P2 motor, motor controller, and power battery, and is used to switch between strong hybrid mode, pure electric mode, or range-extended charging mode. In the strong hybrid mode, the P2 motor outputs torque together with the engine, and in the range-extending charging mode, the engine drives the generator to generate electricity and charge the power battery.

6. The apparatus according to claim 5, characterized in that, The P2 motor is connected to the engine via a clutch, which is controlled to engage or disengage by the vehicle control unit (VCU).

7. The apparatus according to claim 6, characterized in that, The distributed electric drive bridge also includes: The torque vector control module is used to increase torque to the outer wheels and decrease torque to the inner wheels when the vehicle is turning, according to the instructions of the vehicle controller (VCU).

8. The apparatus according to claim 7, characterized in that, The wheel-side motor is an external rotor permanent magnet synchronous motor with a peak torque density ≥20 N·m / kg and a peak power density ≥5 kW / kg.

9. The apparatus according to any one of claims 5 to 8, characterized in that, Also includes: The steer-by-wire system communicates with the vehicle control unit (VCU) and is used to control the steering angle of each wheel according to driver input or autonomous driving commands. The brake-by-wire system communicates with the vehicle control unit (VCU) and is used to implement motor braking via the motor controller and hydraulic braking via the friction brake according to braking requirements.

10. A crane chassis control method, applied to the device according to any one of claims 1 to 9, characterized in that, Includes the following steps: Obtain the vehicle's current speed, required torque, battery SOC, and road gradient; When the battery SOC is higher than the first threshold and the required torque is lower than the second threshold, the system enters pure electric mode and the power battery supplies power to the wheel-side motor. When the battery SOC is lower than the first threshold or the required torque is higher than the second threshold, the range extender or the engine is activated to enter the range extender mode or the strong hybrid mode. During braking, the wheel-side motor is controlled by the motor controller to recover energy and store the recovered electrical energy in the power battery. Under steering conditions, the target torque and steering angle of each wheel are calculated based on the target turning radius, and the torque and steering angle of each wheel are independently controlled by the motor controller to achieve torque vector control and all-wheel steering.

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