Four-wheel drive industrial vehicle and control method

Abstract

The four-wheel drive industrial vehicle comprises a vehicle body, a front drive unit and a rear drive unit, the front drive unit and the rear drive unit are used for providing driving force and arranged at the two ends of the vehicle body respectively, the front drive unit comprises a front drive motor, and the rear drive unit comprises a rear drive motor. According to the four-wheel drive industrial vehicle, the cross-country and gradeability of the electric industrial vehicle can be improved; and dynamic feedback control is adopted, real-time driving of the driving wheels is kept, the driving force can be reasonably distributed, and the industrial vehicle can deal with different road surface working conditions and has real-time driving and escaping capabilities.

Description

Technical Field

[0001] The present invention belongs to the technical field of industrial vehicles, and in particular, relates to a four-wheel drive industrial vehicle and a control method thereof. Background Art

[0002] Battery counterbalanced forklifts are green, environmentally friendly, noiseless and pollution-free, and can handle medium and short distance transportation and stacking of palletized goods. With the development of electric forklift functions, there is a gradual demand for special, outdoor, heavy-load and other working conditions. The traditional drive mode, single drive motor: front motor T-type arrangement, front motor H-type arrangement, front motor middle arrangement, dual-drive motor + dual gearbox arrangement, etc., all arrange the driving force on the front wheels, and do not have the following characteristics: strong acceleration capability, large climbing angle, escape from difficulties and other off-road requirements.

[0003] For the above battery-powered electric forklift wheel drive structure, through the reasonable arrangement of mechanical structure and control logic, it can provide power to the four wheels in real time, effectively ensuring that the forklift can complete various moving actions under multi-state road conditions, and has broad market prospects in the four-wheel drive electric forklift segment.

[0004] The existing four-wheel drive solution is basically set up on an internal combustion forklift platform. It is powered by the engine, and the connecting shaft outputs power to the front and rear axles, driving the tires to drive the entire vehicle to move. Combined with the passability design of the vehicle structure, it can achieve driving in various road scenarios.

[0005] It is desirable to provide an improved four-wheel drive industrial vehicle, in particular to improve the off-road and grade climbing capabilities of an electric industrial vehicle. Summary of the invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a four-wheel drive industrial vehicle, the purpose of which is to improve the off-road and climbing capabilities of the electric industrial vehicle.

[0007] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a four-wheel drive industrial vehicle includes a vehicle body, a front drive unit and a rear drive unit for providing driving force, the front drive unit and the rear drive unit are respectively arranged at two ends of the vehicle body, the front drive unit includes a front drive motor, and the rear drive unit includes a rear drive motor.

[0008] One front drive unit is provided, and the front drive unit also includes a front gearbox assembly connected to the front drive motor, a front drive axle connected to the front gearbox assembly, and two front wheels arranged on the front drive axle.

[0009] Two front drive units are provided.

[0010] The front drive unit also includes a front gearbox assembly connected to the front drive motor and a front wheel arranged on the gearbox assembly.

[0011] The rear drive unit also includes a rear gearbox assembly connected to the rear drive motor, a rear drive axle connected to the rear gearbox assembly, and two steering wheels arranged on the rear drive axle.

[0012] The present invention also provides a control method for a four-wheel drive industrial vehicle. During the driving process of the four-wheel drive industrial vehicle, the real-time driving of the four driving wheels and the self-control of the driving force are maintained according to the obtained driving target value by adopting dynamic feedback control.

[0013] The front drive motor is electrically connected to the main controller, and the rear drive motor is electrically connected to the auxiliary controller.

[0014] When the four-wheel drive industrial vehicle is in a special working condition, the control method comprises the steps of:

[0015] Step 1: The driver obtains the driving target value X(s) of the whole machine according to the throttle opening;

[0016] Step 2, the main controller automatically distributes the driving force of the two front drive units according to the steering angle; the auxiliary controller performs closed-loop control on the driving force of the rear drive unit;

[0017] Step 3: The main controller and the auxiliary controller perform coordinated control, and automatically control the driving force of the front drive unit and the rear drive unit in combination with the four-wheel drive variable transformation function F(x).

[0018] When the four-wheel drive industrial vehicle is in a special working condition, the control method comprises the steps of:

[0019] Step 1: The driver obtains the driving target value X(s) of the whole machine according to the throttle opening;

[0020] Step 2, the main controller performs closed-loop control on the driving force of the front drive unit, and the auxiliary controller performs closed-loop control on the driving force of the rear drive unit;

[0021] Step 3: The main controller and the auxiliary controller perform coordinated control, and automatically control the driving force of the front drive unit and the rear drive unit in combination with the four-wheel drive variable conversion function F'(x).

[0022] The four-wheel drive industrial vehicle of the present invention can improve the off-road and climbing capabilities of the electric industrial vehicle; and adopts dynamic feedback control to maintain the real-time driving of the driving wheels, and can reasonably distribute the driving force. The industrial vehicle can cope with different road conditions and has real-time driving and escape capabilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] This specification includes the following drawings, which show the following contents:

[0024] Figure 1 It is a schematic diagram of the whole machine working condition of the four-wheel drive industrial vehicle of the present invention;

[0025] Figure 2 is a schematic diagram of the structure of the front drive unit;

[0026] Figure 3 This is an exploded view of the components of the front drive unit;

[0027] Figure 4 This is an exploded view of the components of the rear drive unit;

[0028] Figure 5 It is the logic diagram of the starting condition;

[0029] Figure 6 It is the logic diagram of the stop condition;

[0030] Figure 7 It is a schematic diagram of a one-way turn;

[0031] Figure 8 It is a full dual motor logic control diagram;

[0032] Fig. 9 This is an exploded view of the components of another front drive unit;

[0033] Fig.10 It is the front and rear single motor drive logic control diagram;

[0034] Markings in the figure are: 10, vehicle body; 20, front drive unit; 31, front drive motor; 32, motor fasteners; 33, seals; 34, connecting plates; 35, fasteners; 36, front gearbox assembly; 37, inner tire assembly; 38, outer tire assembly; 39, electromagnetic brake; 310, front drive axle; 41, rear gearbox assembly; 42, rear drive motor; 43, electromagnetic brake; 44, flexible connecting shaft; 45, rear drive axle; 46, steering wheel. DETAILED DESCRIPTION

[0035] The specific implementation methods of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, with the aim of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solution of the present invention and facilitating its implementation.

[0036] Embodiment 1

[0037] like Figures 1 to 4As shown, this embodiment provides a four-wheel drive industrial vehicle, including a vehicle body 10, a battery arranged on the vehicle body 10, and a front drive unit and a rear drive unit for providing driving force, the front drive unit and the rear drive unit are respectively arranged at two ends of the vehicle body 10, the front drive unit includes a front drive motor 31, the rear drive unit includes a rear drive motor 42, and the battery provides electrical energy for the front drive motor 31 and the rear drive motor 42.

[0038] Specifically, the four-wheel drive industrial vehicle provided in this embodiment is generally suitable for complex road conditions requiring four-wheel drive power, such as climbing, getting out of trouble, etc., and generally the four drive wheels require a real-time power source.

[0039] Four-wheel drive has the advantages of strong power and good stability. The front and rear drives are powered by the motor at the same time, and all four climbing wheels get driving force, thereby increasing the distribution of friction in the four directions, reducing the risk of vehicle slippage, and being safer and more reliable. Part-time four-wheel drive, real-time four-wheel drive and full-time four-wheel drive use low-speed or high-speed four-wheel drive modes on snow and muddy roads. Four-wheel drive vehicles have obvious advantages when climbing slopes (such as driving into the curb) and driving on unpaved roads (such as mountain roads and the wild). In contrast, two-wheel drive vehicles have only two driving wheels, which are powered by the engine to drive them to rotate to propel the vehicle forward. Two-wheel drive models may have understeer or tail-swinging problems when turning.

[0040] In addition, there are different types of four-wheel drive, including part-time four-wheel drive, real-time four-wheel drive and full-time four-wheel drive. Part-time four-wheel drive requires manual switching of the drive mode and is not applicable when driving on paved roads. Usually, low-speed or high-speed four-wheel drive modes are only used on snow and mud roads. Four-wheel drive has the advantages of strong power and good stability, but it consumes more power.

[0041] In this embodiment, if Figures 1 to 3 As shown, two front drive units are provided, and the two front drive units are arranged on the left and right sides of the vehicle body 10. The front drive unit also includes a front gearbox assembly 36 connected to the front drive motor 31 and a front wheel arranged on the gearbox assembly.

[0042] like Figure 4 As shown, the rear drive unit further includes a rear gearbox assembly 41 connected to a rear drive motor 42, a rear drive axle 45 connected to the rear gearbox assembly 41, and two steering wheels 46 disposed on the rear drive axle 45, wherein the rear gearbox assembly 41 is located between the two steering wheels 46. The rear drive axle 45 includes a gear transmission ratio and a wheel-side reduction ratio power output, and is provided with a limited slip differential, so that the rear drive axle 45 can transmit driving force in real time.

[0043] like Figure 4As shown, the rear drive unit further includes an electromagnetic brake 43 , which is connected to the rear drive motor 42 , and is used to brake the rear drive motor 42 .

[0044] The motors of the two front drive units provide power. When the driver needs to control the industrial vehicle to turn left or right, the front drive motors 31 of the two front drive units perform differential control, so that the two front wheels have a speed difference, so that the whole vehicle deflects to the side with slower wheel speed, and at the same time cooperates with the certain deflection angle set by the steering wheel 46, and finally achieves the purpose of body steering. The rear drive unit also provides driving force, and the rear drive motor 42 is connected to the rear gearbox assembly 41 through a flexible transmission shaft.

[0045] like Figure 2 and Figure 3 As shown, the front drive motor 31 is fixedly connected to the connecting plate 34 through the motor fastener 32, and the connecting plate 34 is fixedly connected to the front gearbox assembly 36 through the fastener 35. The front wheel is fixedly mounted on the output end of the front gearbox assembly 36, and the output end of the front drive motor 31 is connected to the input end of the front gearbox assembly 36. The front wheel is a dual-tire structure, and the front wheel includes an inner tire assembly 37 and an outer tire assembly 38, and the outer tire assembly 38 is located outside the inner tire assembly 37.

[0046] As a preferred method, the parking brake function can be turned on and off by controlling the hydraulic pressure maintenance and pressure relief of the brake, and the front gearbox assembly 36 has the functions of travel braking and parking braking. Service braking: The travel can be driven downward by the foot brake set in the vehicle body 10, and the driving torque of the whole machine is transmitted through hydraulic pressure to finally achieve travel braking; Parking braking: The whole vehicle can be locked according to the actual working condition of the whole machine to prevent the whole vehicle from moving relative to the ground, and the hydraulic power signal is driven by an electrical signal for control.

[0047] The present invention also provides a control method for a four-wheel drive industrial vehicle. During the driving process of the four-wheel drive industrial vehicle, dynamic feedback control is adopted to maintain real-time driving of four driving wheels and self-control of driving force according to the obtained driving target value.

[0048] The front drive motor 31 is electrically connected to the main controller, and the front drive motor 31 is controlled by the main controller. The rear drive motor 42 is electrically connected to the auxiliary controller, and the rear drive motor 42 is controlled by the auxiliary controller.

[0049] The four-wheel drive industrial vehicle can work in the starting condition. At the moment of starting, the front wheel negative pressure hydraulic brake is filled with fluid to cancel the brake, the electromagnetic brake of the rear drive unit is energized, the rear drive motor 42 is released, and the whole machine is braked. At the same time, the front and rear drives obtain the forward / reverse driving force through the motor, driving the whole machine to move forward / backward. The specific process is as follows Figure 5 The specific description is as follows.

[0050] When the four-wheel drive industrial vehicle is working in the starting condition, the control method of the four-wheel drive industrial vehicle includes the following steps:

[0051] Step 1: The process starts;

[0052] Step 2: The whole machine receives the startup command;

[0053] Step 3: Continue to determine whether the whole machine has released the brake command until the parking brake is released. The actual action is to input hydraulic energy and release the parking brake.

[0054] Step 4: The main controller and the auxiliary controller start working, and simultaneously drive the front drive motor 31 and the rear drive motor 42 to start outputting power;

[0055] Step 5: The whole machine is started up;

[0056] Step 6: The process ends.

[0057] Four-wheel drive industrial vehicles can work in a stopped state. At the moment of stopping, the whole machine cancels power output. According to the brake pedal stroke operated by the driver, the whole machine provides corresponding reverse braking torque to control the whole machine to decelerate smoothly. When the speed of the whole machine drops to 0 or a given value, the parking brake takes effect and the whole vehicle is locked to ensure that all wheels of the whole vehicle are locked to ensure safety. The specific process is as follows: Figure 6 The specific description is as follows.

[0058] When the four-wheel drive industrial vehicle is working in the starting condition, the control method of the four-wheel drive industrial vehicle includes the following steps:

[0059] Step 1: The process starts;

[0060] Step 2: The whole machine receives the stop command;

[0061] Step 3: The main controller and the auxiliary controller simultaneously drive the front drive motor and the rear drive motor to stop outputting power;

[0062] Step 4: Continue to detect the motor speed until the output speed drops to 0 (or within a relatively small speed range), and give a parking signal for parking brake;

[0063] Step 5: The negative pressure brake stops hydraulic output, the parking brake takes effect, and the front drive wheels are locked;

[0064] Step 6: Implement vehicle braking;

[0065] Step 7: The process ends.

[0066] like Figure 7As shown, when a four-wheel drive industrial vehicle is turning during driving, at the moment of turning, the driver manipulates the steering wheel to deflect a certain angle between -540° and 540° (one and a half turns clockwise and counterclockwise), and the hydraulic power steering response steering system set in the vehicle body turns the left / right steering cylinder stroke, driving the left and right steering wheels 46 to form a certain steering angle, so that the whole vehicle rotates around the formed rotation center. At the same time, the left front wheel steering speed and the right front wheel steering speed are calculated through control calculation, and the left and right wheel steering speeds of the steering wheel 46 are automatically matched and adjusted through the differential.

[0067] When turning, the vehicle posture and the steering wheel 46 turning angle are as follows: Figure 7 As shown, the whole system satisfies: the angular velocity is equal, and the direction of the wheel tangent velocity is perpendicular to the line connecting the wheel rotation to the rotation center point. Among them: V1 is the average speed of the inner double wheels of the front driving wheel turning, V2 is the average speed of the outer double wheels of the front driving wheel turning, V3 is the speed of the inner wheel of the rear driving wheel turning, V4 is the speed of the outer wheel of the rear driving wheel turning, R1 is the vertical distance between the center of the inner double wheels of the front driving wheel turning and the rotation center of the whole vehicle; R2 is the vertical distance between the center of the outer double wheels of the front driving wheel turning and the rotation center of the whole vehicle, R3 is the vertical distance between the inner wheel of the rear driving wheel turning and the rotation center of the whole vehicle; R4 is the vertical distance between the outer wheel of the rear driving wheel and the rotation center of the whole vehicle.

[0068] Specific:

[0069]

[0070] Regarding the front drive wheels, combined with the real-time feedback of the wheel steering angle, the electronic control monitors the wheel speed, motor speed, and power output, and makes real-time adjustments to ensure that each wheel is allocated a reasonable driving force; regarding the adjustment method of the rear drive wheel driving force and speed, the left and right rear wheels are adjusted through the differential and differential lock.

[0071] When the vehicle is in special working conditions, such as when three wheels are suspended, one wheel is slipping, or some wheels need to output greater power, the system detects the need for power output and distributes the power reasonably so that the vehicle can better complete the expected action. A feasible control logic is introduced below.

[0072] like Figure 8 The figure shows the four-wheel drive force determination and control logic control diagram. Taking into account the real-time response to the set speed, manual steering angle, and the dynamic feedback changes of the ground to the front and rear wheels, real-time power output adjustment is performed. Specifically: when the front wheel system and the rear drive wheel system slip, the system determines that a wheel system is suspended according to the algorithm, and then increases the driving power on the other side to get the body out of trouble. The relative slip of the front and rear wheels will not change due to no load, full load, or climbing.

[0073] The driver sets the speed through the accelerator pedal, and the signal is transmitted to the main controller and the auxiliary controller for coordinated control. The two front drive motors 31 and the rear drive motor 42 provide power synchronously and respond to the steering angle in real time. The speed of the front drive motor 31 and the rear drive motor 42 is closed-loop controlled through encoder feedback.

[0074] Generally, the main controller is a front drive unit controller that controls the front drive motor 31. The main controller has the following functions: outputting the driving force of the front drive motor, exchanging data with the auxiliary controller, and being able to participate in the core algorithm of driving force distribution through digital-to-analog conversion through IO detection, and outputting the calculation results in real time, and guiding the controller to output power. The auxiliary controller is a rear drive unit controller that controls the rear drive motor 42. It is mainly responsible for executing the power output of the rear drive motor, and will report the motor speed feedback obtained to the main controller, and accept the adjustment instructions fed back by the main controller to output the power of the rear drive unit.

[0075] like Figure 8 As shown, when the four-wheel drive industrial vehicle is in special working conditions, the special working conditions include getting out of trouble, single wheel hanging in the air, climbing and other working conditions. The control method of the four-wheel drive industrial vehicle includes the following steps:

[0076] Step 1: The driver obtains the driving target value X(s) of the whole machine according to the throttle opening;

[0077] Step 2: The main controller automatically distributes the driving force of the two front drive units according to the steering angle; and the auxiliary controller performs closed-loop control on the driving force of the rear drive unit;

[0078] Step 3: The main controller and the auxiliary controller perform coordinated control, and automatically control the driving force of the front drive unit and the rear drive unit in combination with the four-wheel drive variable transformation function F(x). The four-wheel drive variable transformation function F(x) is as follows:

[0079]

[0080] Among them, N1 is the speed ratio of the front drive unit; N2 is the speed ratio of the rear drive unit; N3 is the speed ratio of the rear drive axle 45; n1 is the speed of the front drive motor 31; n2 is the speed of the rear drive motor 42; D1 is the front wheel tire diameter; D2 is the steering wheel 46 tire diameter.

[0081] Specifically, in the above step 1, X(s) is the throttle opening corresponding to the expected vehicle speed (percentage), and X(s) is in the range of 0 to 100%.

[0082] In the above step 2, the main controller W2 automatically matches the output of the two front-drive motors 31 according to the steering angle (at this time, the inner drive unit and the outer drive unit are distinguished by the steering direction), and executes the action through the mechanical structures such as the connecting plate and the front gearbox assembly 36. During driving, the road resistance interference will affect the motor speed. By detecting the speed of the two front-drive motors 31 in real time, the main controller performs closed-loop control on the power output of the two front-drive motors 31.

[0083] In the above step 2, the auxiliary controller W1 is driven and the action is performed through the mechanical structure such as the motor gearbox output shaft. The road resistance interference will affect the speed of the rear-drive motor 42. By detecting the speed of the rear-drive motor 42 in real time, the auxiliary controller performs closed-loop control on the power output of the rear-drive motor 42, and the power differential of the left and right steering wheels 46 is automatically adjusted by the differential arranged in the rear axle assembly.

[0084] In the above step 3, the actual output speed of the front drive motor 31 and the rear drive motor 42 under the control of the main controller and the auxiliary controller is detected in real time, and the power output of the two front wheels and the two steering wheels 46 is automatically controlled in combination with the F(x) operation function to ensure stable and continuous output of the four-wheel drive force and ensure that the whole machine is consistent with the driver's operating intention.

[0085] Table 1 Main codes and range of changes

[0086]

[0087] Among them, the four-wheel drive variable conversion mode in Table 1 is used as a calculation method for determining special driving conditions. The technical solution determines the suspension method including but not limited to the above four-wheel drive variable conversion function, and requests to protect the logical judgment method based on the above structural arrangement.

[0088] The four-wheel drive industrial vehicle can work in a braking regeneration charging condition. When the four-wheel drive industrial vehicle is on a long downhill slope or braking, the reverse whole machine torque can drive the front drive motor 31 and the rear drive motor 42 to rotate. The front drive motor 31 and the rear drive motor 42 convert kinetic energy into electrical energy, which is inverted into direct current through the electronic control unit and converted into chemical energy and stored in the battery. While reducing the vehicle speed, the excess energy can be recovered to a certain extent, ultimately achieving the purpose of energy saving.

[0089] The four-wheel drive industrial vehicle can operate in a motor reverse braking condition. When the controller provides reverse current to the front drive motor 31 and the rear drive motor 42, the front drive motor 31 and the rear drive motor 42 can output reverse torque to provide regenerative braking to the front wheel and the steering wheel 46 respectively; when a directional current is provided, a reverse braking force can be provided, so that the whole vehicle has a short braking distance.

[0090] Embodiment 2

[0091] In this embodiment, if Fig. 9 As shown, one front drive unit is provided, and the front drive unit further includes an electromagnetic brake 39, a front gearbox assembly 36 connected to the front drive motor 31, a front drive axle 310 connected to the front gearbox assembly 36, and two front wheels arranged on the front drive axle 310. The electromagnetic brake 39 is connected to the front drive motor 31, and the electromagnetic brake 39 is used to brake the front drive motor 31.

[0092] The structure of the front drive axle 310 is well known to those skilled in the art. The front drive axle 310 includes a gear transmission ratio and a wheel reduction ratio power output, and is provided with a limited slip differential, so that the front drive axle 310 can transmit driving force in real time.

[0093] In this embodiment, compared with the front dual-wheel drive, the main features of the single-wheel drive unit include: a shared gearbox, drive motor and electronic control system for the left and right axles, occupying a larger vehicle body space and generally being more cost-effective.

[0094] like Fig.10 As shown, in response to the steering angle and ground interference, the motor drive is adjusted in real time to maintain the four-wheel drive, so that the whole machine has the four-wheel drive capability. Compared with the solution of embodiment 1, the four-wheel drive change and control strategy need to be adjusted accordingly.

[0095] When the four-wheel drive industrial vehicle is in a special working condition, the control method of the four-wheel drive industrial vehicle includes the following steps:

[0096] Step 1: The driver obtains the driving target value X(s) of the whole machine according to the throttle opening;

[0097] Step 2: The main controller performs closed-loop control on the driving force of the front drive unit, and the auxiliary controller performs closed-loop control on the driving force of the rear drive unit;

[0098] Step 3: The main controller and the auxiliary controller perform coordinated control, and automatically control the driving force of the front drive unit and the rear drive unit in combination with the four-wheel drive variable transformation function F'(x). The four-wheel drive variable transformation function F'(x) is as follows:

[0099]

[0100] Among them, N'1 is the speed ratio of the front drive unit; N'2 is the speed ratio of the rear drive unit; N'3 is the speed ratio of the rear drive axle 45; N'4 is the speed ratio of the front drive axle 310; n'1 is the speed of the front drive motor 31; n'2 is the speed of the rear drive motor 42; D'1 is the front wheel tire diameter; D'2 is the steering wheel 46 tire diameter.

[0101] In the above step 1, X(s) is the throttle opening corresponding to the expected vehicle speed (percentage), and X(s) is in the range of 0 to 100%.

[0102] In the above step 2, the main controller W2 automatically matches the output of the two front-drive motors 31 according to the steering angle (at this time, the inner drive unit and the outer drive unit are distinguished by the steering direction), and executes the action through the mechanical structures such as the connecting plate and the front gearbox assembly 36. During driving, the road resistance interference will affect the motor speed. By detecting the speed of the two front-drive motors 31 in real time, the main controller performs closed-loop control on the power output of the two front-drive motors 31.

[0103] The main controller W2 drives the output shaft and other mechanical structures of the front transmission assembly 36 to perform actions. The road resistance interference will affect the rotation speed of the front drive motor 31. By detecting the rotation speed of the front drive motor 31 in real time, the main controller performs closed-loop control on the power output of the front drive motor 31, and the power differential between the left and right front wheels is automatically adjusted through the differential set in the front drive axle 310.

[0104] In the above step 2, the auxiliary controller W1 is driven and the action is performed through the mechanical structure such as the motor gearbox output shaft. The road resistance interference will affect the speed of the rear-drive motor 42. By detecting the speed of the rear-drive motor 42 in real time, the auxiliary controller performs closed-loop control on the power output of the rear-drive motor 42, and the power differential of the left and right steering wheels 46 is automatically adjusted by the differential arranged in the rear axle assembly.

[0105] In the above step 3, the actual output speed of the front drive motor 31 and the rear drive motor 42 under the control of the main controller and the auxiliary controller is detected in real time, and the power output of the two front wheels and the two steering wheels 46 is automatically controlled in combination with the F(x) operation function to ensure stable and continuous output of the four-wheel drive force and ensure that the whole machine is consistent with the driver's operating intention.

[0106] The present invention is described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention; or the above concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A four-wheel drive industrial vehicle, comprising a vehicle body, characterized in that: It also includes a front drive unit and a rear drive unit for providing driving force. The front drive unit and the rear drive unit are respectively arranged at two ends of the vehicle body. The front drive unit includes a front drive motor, and the rear drive unit includes a rear drive motor.

2. The four-wheel drive industrial vehicle according to claim 1, characterized in that: One front drive unit is provided, and the front drive unit also includes a front gearbox assembly connected to the front drive motor, a front drive axle connected to the front gearbox assembly, and two front wheels arranged on the front drive axle.

3. The four-wheel drive industrial vehicle according to claim 1, characterized in that: Two front drive units are provided.

4. The four-wheel drive industrial vehicle according to claim 3, characterized in that: The front drive unit also includes a front gearbox assembly connected to the front drive motor and a front wheel arranged on the gearbox assembly.

5. The four-wheel drive industrial vehicle according to any one of claims 1 to 4, characterized in that: The rear drive unit also includes a rear gearbox assembly connected to the rear drive motor, a rear drive axle connected to the rear gearbox assembly, and two steering wheels arranged on the rear drive axle.

6. The control method of a four-wheel drive industrial vehicle according to any one of claims 1 to 5, characterized in that: During the driving process of the four-wheel drive industrial vehicle, the real-time driving of the four driving wheels and the self-control of the driving force are maintained according to the obtained driving target value by adopting dynamic feedback control.

7. The control method of a four-wheel drive industrial vehicle according to claim 6, characterized in that: The front drive motor is electrically connected to the main controller, and the rear drive motor is electrically connected to the auxiliary controller.

8. The control method of a four-wheel drive industrial vehicle according to claim 7, characterized in that: When the four-wheel drive industrial vehicle is in a special working condition, the control method comprises the steps of: Step 1: The driver obtains the driving target value X(s) of the whole machine according to the throttle opening; Step 2, the main controller automatically distributes the driving force of the two front drive units according to the steering angle; the auxiliary controller performs closed-loop control on the driving force of the rear drive unit; Step 3: The main controller and the auxiliary controller perform coordinated control, and automatically control the driving force of the front drive unit and the rear drive unit in combination with the four-wheel drive variable transformation function F(x).

9. The control method of a four-wheel drive industrial vehicle according to claim 7, characterized in that: When the four-wheel drive industrial vehicle is in a special working condition, the control method comprises the steps of: Step 1: The driver obtains the driving target value X(s) of the whole machine according to the throttle opening; Step 2, the main controller performs closed-loop control on the driving force of the front drive unit, and the auxiliary controller performs closed-loop control on the driving force of the rear drive unit; Step 3: The main controller and the auxiliary controller perform coordinated control, and automatically control the driving force of the front drive unit and the rear drive unit in combination with the four-wheel drive variable conversion function F'(x).

Images