An electronic differential control method and device for a heavy shuttle car

Abstract

The present invention belongs to the technical field of heavy-duty vehicle travel control and provides an electronic differential control method and device for a heavy-duty shuttle vehicle. This method solves the problem of a large turning radius and slippage or dragging of some tires during pure hydraulic steering. The vehicle controller obtains the accelerator pedal opening of the target shuttle vehicle during the steering phase; the initial given speed of the shuttle vehicle during the steering phase is determined based on a mapping relationship; the length of the oil cylinder displacement sensor of the target shuttle vehicle during the steering phase is obtained; the steering angle of the shuttle vehicle during the steering phase is determined based on the mapping relationship; the turning radius of the target shuttle vehicle is determined by analyzing the mechanical structure based on the steering angle; and finally, the differential coefficient of each wheel is calculated. Finally, combined with the initial given speed, the actual given speed output of the travel motor is completed to realize electronic differential control of the shuttle vehicle. The present invention can improve the steering performance and driving stability of heavy-duty vehicles.

Description

Technical Field

[0001] The present invention belongs to the technical field of heavy vehicle travel control, and in particular relates to an electronic differential control method and device for a heavy shuttle vehicle. Background Art

[0002] Heavy-duty shuttle vehicles are becoming increasingly common in underground coal mines, particularly in large mines. These vehicles are often responsible for transporting coal during the mining process. Traditionally, these vehicles have had simpler steering systems, often employing purely hydraulic rotation. The driver controls the hydraulic steering wheel and increases the pressure in the hydraulic circuit cylinders to achieve steering.

[0003] For heavy vehicles, using purely hydraulic steering methods and devices will increase the vehicle's turning radius, and the electric drive system cannot obtain the tire steering angle and adjust the output, which may cause some tires to slip or drag, increase the motor's reactive power consumption and tire wear, and poor vehicle operability and driving comfort. Summary of the Invention

[0004] In order to solve at least one of the above technical problems existing in the prior art, the present invention provides an electronic differential control method and device for a heavy-duty shuttle car.

[0005] The present invention is implemented by the following technical solution: an electronic differential control method for a heavy shuttle car, comprising the following steps:

[0006] S1: Obtain the accelerator pedal opening and cylinder displacement length of the target shuttle during the steering phase;

[0007] S2: determining a preliminary given speed of the target shuttle during the turning phase according to a first mapping relationship between the accelerator pedal opening and the output speed of the target shuttle;

[0008] S3: determining the steering angle of the target shuttle in the steering phase according to a second mapping relationship between the displacement length of the oil cylinder and the steering angle of the target shuttle;

[0009] S4: Analyze the geometric structure of the target shuttle according to the steering angle and determine the steering radius of the target shuttle;

[0010] S5: Determine the differential speed coefficient of the inner wheel and the outer wheel of the target shuttle according to the turning radius;

[0011] S6: According to the initial given speed of the target shuttle during the steering phase and the differential coefficient between the inner wheel and the outer wheel, the actual given speed of the inner wheel and the outer wheel of the target shuttle is determined and output to control the driving and steering of the target shuttle.

[0012] Preferably, in step S1, the numerical range of the accelerator pedal opening is 0 to 100; the cylinder displacement length is the cylinder displacement length of the target shuttle at the target time, where the target time refers to the time when the accelerator pedal electrical signal is generated.

[0013] Preferably, in step S2, the first mapping relationship is:

[0014]

[0015] Where, is the initial given speed of the target shuttle during the turning phase; is the set maximum speed of the motor; is the accelerator pedal opening; is the acceleration coefficient.

[0016] Preferably, in step S3, the second mapping relationship is:

[0017]

[0018] Where, is the steering angle of the target shuttle; is the length of one side of the triangle formed by the target shuttle when it is traveling; is the length of the other side of the triangle formed by the target shuttle when it is traveling; is the displacement length of the cylinder, that is, the length of the hypotenuse of the triangle; It is the angle of the triangle formed by the shuttle car when it is traveling.

[0019] Preferably, in step S4, according to the steering angle of the target shuttle, a steering arc is constructed by the front and rear tires to obtain a turning radius of the target shuttle:

[0020]

[0021] Where, is the turning radius of the target shuttle; is the center distance between the front and rear tires; is the steering angle of the target shuttle.

[0022] Preferably, in step S5, the calculation formula of the differential coefficient of the inner wheel and the outer wheel during the turning phase of the target shuttle is:

[0023]

[0024]

[0025] Where, 、 are the differential coefficients of the inner and outer wheels respectively; is the center distance between the front and rear tires; is the center distance between the left and right tires; is the steering angle of the target shuttle.

[0026] Preferably, in step S6, the calculation formula for the actual given rotation speed of the inner wheel and outer wheel of the target shuttle is:

[0027]

[0028]

[0029] Where, 、 are the actual given speeds of the inner and outer wheels respectively; 、 are the differential coefficients of the inner and outer wheels respectively; is the center distance between the front and rear tires; is the center distance between the left and right tires; is the steering angle of the target shuttle; is the initial given speed of the target shuttle during the turning phase.

[0030] Preferably, during the turning phase of the target shuttle, the wheels in the same direction as the turning direction are inner wheels, and the wheels in the opposite direction are outer wheels.

[0031] The present invention also provides an electronic differential control device for a heavy-duty shuttle vehicle, which is based on the electronic differential control method for a heavy-duty shuttle vehicle and includes a first acquisition module, a first determination module, a second acquisition module, a second determination module, a third determination module, and a first control module;

[0032] The first acquisition module is configured to acquire the accelerator pedal opening of the target shuttle during the steering phase, and the first determination module is configured to determine the preliminary given speed of the target shuttle during the steering phase based on a first mapping relationship. The second acquisition module is configured to acquire the cylinder displacement length from the cylinder displacement sensor, and the second determination module is configured to determine the steering angle of the target shuttle during the steering phase based on the second mapping relationship and in combination with the mechanical structure of the target shuttle. The third determination module is configured to determine the turning radius and the differential speed coefficient of the inner and outer wheels of the target shuttle based on the steering angle and in combination with the distances between the front and rear and left and right tires of the target shuttle, and ultimately determine the actual given speed of the inner and outer wheels of the target shuttle based on the preliminary given speed. The first control module is configured to control the inner and outer wheel motors to output the final actual given speed.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] When the target shuttle turns, the present invention calculates the turning radius of the target shuttle by adding a cylinder displacement sensor, controls the inner wheel and outer wheel motors to output appropriate rotational speeds, and cooperates with the vehicle's hydraulic steering system to reduce the turning radius of the shuttle, making the vehicle's steering process smoother, reducing tire slip and drag, realizing electronic differential, and improving the steering performance and driving stability of heavy vehicles.

[0035] The present invention further optimizes the travel control strategy of the existing shuttle car and adds an electronic differential function. It conforms to the development trend of green environmental protection and automation and intelligence in coal mines, can increase the travel operating range of the shuttle car, promote the update of the shuttle car's automation function, and meet market development needs. In addition, this solution has reference significance for the steering design of other new energy vehicles and can bring additional benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 Schematic diagram of the control flow of this embodiment;

[0038] Figure 2 Schematic diagram of a first mapping relationship between the accelerator pedal opening and the target shuttle output speed in this embodiment;

[0039] Figure 3 Schematic diagram of a second mapping relationship between the oil cylinder displacement length and the target shuttle steering angle of this embodiment;

[0040] Figure 4 Schematic diagram of the mapping relationship between the steering angle and the actual given rotational speeds of the inner and outer wheels in this embodiment;

[0041] Figure 5 Schematic diagram of the mapping relationship between the accelerator pedal opening and the actual given rotation speeds of the inner and outer wheels in this embodiment;

[0042] Figure 6 Schematic diagram of the geometric structure at the steering angle of this embodiment;

[0043] Figure 7 is a schematic diagram of the device module of this embodiment;

[0044] Figure 8 Schematic diagram of the turning arc of this embodiment. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present invention are clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other implementations derived by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts are within the scope of protection of the present invention.

[0046] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the conditions under which the present invention can be implemented. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should fall within the scope of the technical content disclosed in the present invention without affecting the efficacy and purpose that can be achieved by the present invention. It should be noted that in this specification, relational terms such as first and second are only used to distinguish one entity from several other entities, and do not necessarily require or imply any actual relationship or order between these entities.

[0047] The present invention provides an embodiment:

[0048] like Figure 1 As shown, a method for electronic differential control of a heavy shuttle vehicle comprises the following steps:

[0049] S1: Obtain the accelerator pedal opening and cylinder displacement length of the target shuttle during the steering phase;

[0050] S2: determining a preliminary given speed of the target shuttle during the turning phase according to a first mapping relationship between the accelerator pedal opening and the output speed of the target shuttle;

[0051] S3: determining the steering angle of the target shuttle in the steering phase according to a second mapping relationship between the displacement length of the oil cylinder and the steering angle of the target shuttle;

[0052] S4: Analyze the geometric structure of the target shuttle according to the steering angle and determine the steering radius of the target shuttle;

[0053] S5: Determine the differential speed coefficient of the inner wheel and the outer wheel of the target shuttle according to the turning radius;

[0054] S6: According to the initial given speed of the target shuttle and the differential coefficient of the inner wheel and outer wheel in the steering phase, the actual given speed of the inner wheel and outer wheel of the target shuttle is determined and output, and the driving and steering of the target shuttle is controlled to realize the electronic differential control of the target shuttle.

[0055] In step S1, it should be noted that when the driver depresses the shuttle's accelerator pedal, the control system generates a corresponding electrical signal based on the accelerator pedal opening, such as a voltage signal, current signal, or other communication signal. The system controller receives this signal and converts it into an easily understood accelerator pedal opening value. It is understood that due to mechanical limitations, the accelerator pedal opening has a certain range. In the embodiment of the present application, a fixed numerical range of 0-100 is set for the accelerator pedal opening. After detecting the electrical signal, the numerical value of the accelerator pedal opening can be determined based on the numerical correspondence between the accelerator pedal opening and the electrical signal. Simultaneously, the cylinder displacement length at the target time is obtained. The target time here refers to the moment when the accelerator pedal electrical signal is generated. The two are performed synchronously, with no temporal or logical precedence.

[0056] like Figure 2 As shown, in step S2, the first mapping relationship between the accelerator pedal opening and the target shuttle output speed is:

[0057]

[0058] Where, is the initial given speed of the target shuttle during the turning phase; is the set maximum speed of the motor; is the accelerator pedal opening. This initial given speed is not output directly and needs to be combined with subsequent steps.

[0059] Normally, the initial given speed of the target shuttle in the turning phase increases slowly at the beginning and end of the pedal stroke, and increases quickly in the middle. The present invention adds an acceleration coefficient to the mapping relationship between the accelerator pedal opening and the initial given speed. , which can be set according to actual needs. The smaller the value, the smaller the slope in the initial and final stages, and the slower the speed increases; the larger the slope in the middle stage, the faster the speed increases, and vice versa. This application does not limit this.

[0060] like Figure 3 、 Figure 6 As shown, in step S3, the second mapping relationship between the cylinder displacement length and the target shuttle steering angle is:

[0061]

[0062] Where, is the steering angle of the target shuttle; is the length of one side of the triangle formed by the target shuttle when it is traveling; is the length of the other side of the triangle formed by the target shuttle when it is traveling; is the displacement length of the cylinder, that is, the length of the hypotenuse of the triangle; It is the angle of the triangle formed when the shuttle car is moving. The three vertices of this triangle are respectively the hinge points of the front and rear frames and the two endpoints of the oil cylinder.

[0063] It should be particularly noted that according to the physical structure of the target shuttle car frame (including the frame, steering drive shaft, tire structure, etc.) and the position of the oil cylinder, a specific geometric structure is formed. By analyzing this structure, the second mapping relationship between the oil cylinder length and the vehicle steering angle can be obtained.

[0064] In step S4, according to the steering angle of the target shuttle car, a steering arc is constructed by the front and rear tires, as Figure 8 shown, and the steering radius of the target shuttle car is obtained as:

[0065]

[0066] In the formula, is the steering radius of the target shuttle car; is the center distance between the front and rear tires; is the steering angle of the target shuttle car.

[0067] In step S5, according to the steering radius, the differential coefficients of the inner and outer wheels during the steering stage of the target shuttle car are determined as:

[0068]

[0069]

[0070] In the formula, and are respectively the differential coefficients of the inner and outer wheels; is the center distance between the front and rear tires; is the center distance between the left and right tires; is the steering angle of the target shuttle car. During the steering stage of the target shuttle car, the wheel in the same direction as the turning direction is the inner wheel, and the wheel in the opposite direction is the outer wheel; that is, when the shuttle car turns left, the left wheel is the inner wheel and the right wheel is the outer wheel; when it turns right, the right wheel is the inner wheel and the left wheel is the outer wheel. The turning direction can be judged according to the displacement length of the oil cylinder. The specific method is to calibrate the length Lm of the left oil cylinder when going straight. If L < Lm, the vehicle turns left; if L > Lm, the vehicle turns right. The displacement length of the oil cylinder is measured by a displacement sensor installed in the oil cylinder.

[0071] In step S6, according to the initially given speed and the differential coefficients of the inner and outer wheels during the steering stage of the target shuttle car, the actually given speeds of the inner and outer wheels of the target shuttle car are determined as: The given speeds of the inner wheels of the front and rear wheels are the same, and the given speeds of the outer wheels are also the same.

[0072]

[0073]

[0074] Where, 、 are the actual given speeds of the inner and outer wheels respectively; 、 are the differential coefficients of the inner and outer wheels respectively; is the center distance between the front and rear tires; is the center distance between the left and right tires; is the steering angle of the target shuttle; is the initial given speed of the target shuttle during the turning phase.

[0075] It should be noted that the turning stage mentioned in the present invention does not only refer to a large-angle turn and lane change during the vehicle's travel in a narrow sense, but also refers to any stage of the vehicle's travel in a broad sense. The above steps also play a role in any stage of the shuttle's travel. For example, straight driving can be considered as a turn with a steering angle close to 0 degrees and a very large turning radius.

[0076] It is understandable that, when the actual given speed of the shuttle car during travel is determined, the control system can enable the travel motor to output the corresponding actual given speed to drive the target shuttle car to travel and turn normally.

[0077] Figure 4 This diagram shows the mapping between the target shuttle's steering angle and the actual speeds of the inner and outer wheels, assuming the accelerator pedal opening remains unchanged (i.e., the initial speed setting remains unchanged). The steering angle range is 0-45 degrees, the initial speed setting is fixed at 1000, the center-to-center distance between the front and rear tires is 6000, and the center-to-center distance between the left and right tires is 4500.

[0078] Figure 5 The following diagram shows the mapping relationship between the target shuttle's accelerator pedal opening and the actual given speeds of the inner and outer wheels, assuming a constant steering angle. The accelerator pedal opening range is 0-100 degrees, the steering angle is fixed at 35 degrees, the center-to-center distance between the front and rear tires is 6000, and the center-to-center distance between the left and right tires is 4500.

[0079] In particular, the above Figure 4 and Figure 5 Set in 、 、 、 、 The value or range of values is only a special case in all application scenarios of the present invention and is only for the convenience of drawing and understanding. The method provided by the present invention does not make fixed requirements for the above variables.

[0080] like Figure 7As shown, the present invention also provides an electronic differential control device for a heavy-duty shuttle vehicle, which is based on the electronic differential control method for a heavy-duty shuttle vehicle and includes a first acquisition module, a first determination module, a second acquisition module, a second determination module, a third determination module, and a first control module;

[0081] The first acquisition module is used to obtain the accelerator pedal opening of the target shuttle during the turning phase. Usually, the accelerator pedal itself can send an analog signal to reflect its opening;

[0082] The first determination module, namely the analog input module 1, is used to determine the initial given speed of the target shuttle during the driving phase according to the first mapping relationship;

[0083] The second acquisition module, namely the cylinder displacement sensor, is usually installed inside the cylinder to obtain the cylinder displacement length and send out an analog signal;

[0084] The second determination module, namely the analog input module 2, is used to determine the steering angle of the target shuttle in the steering phase according to the second mapping relationship and in combination with the mechanical structure of the target shuttle;

[0085] The third determination module, or main controller, is typically a PLC (Programmable Logic Controller). It determines the target shuttle's turning radius and the differential speed coefficient between the inner and outer wheels based on the steering angle and the distance between the front and rear and left and right tires of the target shuttle. Finally, it determines the actual given speed of the target shuttle's inner and outer wheels based on the initial given speed.

[0086] The first control module is a motor controller or a frequency converter, which controls the inner and outer wheel motors to output the final actual given speed by receiving the communication signal from the main controller.

[0087] The foregoing description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be readily conceived by a person skilled in the art within the technical scope disclosed herein should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. An electronic differential control method for a heavy shuttle vehicle, characterized in that: The following steps are involved: S1: Obtain the accelerator pedal opening and cylinder displacement length of the target shuttle during the steering phase; S2: determining a preliminary given speed of the target shuttle during the turning phase according to a first mapping relationship between the accelerator pedal opening and the output speed of the target shuttle; The first mapping relationship is: Where, is the initial given speed of the target shuttle during the turning phase; is the set maximum speed of the motor; is the accelerator pedal opening; is the acceleration coefficient; S3: determining the steering angle of the target shuttle in the steering phase according to a second mapping relationship between the displacement length of the oil cylinder and the steering angle of the target shuttle; The second mapping relationship is: Where, is the steering angle of the target shuttle; is the length of one side of the triangle formed by the target shuttle when it is traveling; is the length of the other side of the triangle formed by the target shuttle when it is traveling; is the displacement length of the cylinder, that is, the length of the hypotenuse of the triangle; is the angle of the triangle formed by the shuttle when it is moving; S4: Analyze the geometric structure of the target shuttle according to the steering angle and determine the steering radius of the target shuttle; S5: Determine the differential speed coefficient of the inner wheel and the outer wheel of the target shuttle according to the turning radius; S6: According to the initial given speed of the target shuttle during the steering phase and the differential coefficient between the inner wheel and the outer wheel, the actual given speed of the inner wheel and the outer wheel of the target shuttle is determined and output to control the driving and steering of the target shuttle.

2. The electronic differential control method for a heavy shuttle car according to claim 1, characterized in that In step S1, the numerical range of the accelerator pedal opening is 0 to 100; the cylinder displacement length is the cylinder displacement length of the target shuttle at the target time, where the target time refers to the time when the accelerator pedal electrical signal is generated.

3. The electronic differential control method for a heavy shuttle car according to claim 2, characterized in that In step S4, according to the steering angle of the target shuttle, a turning arc is constructed by the front and rear tires to obtain the turning radius of the target shuttle: Where, is the turning radius of the target shuttle; is the center distance between the front and rear tires; is the steering angle of the target shuttle.

4. The electronic differential control method for a heavy shuttle car according to claim 3 is characterized in that In step S5, the calculation formula of the differential coefficient between the inner wheel and the outer wheel during the turning phase of the target shuttle is: Where, 、 are the differential coefficients of the inner and outer wheels respectively; is the center distance between the front and rear tires; is the center distance between the left and right tires; is the steering angle of the target shuttle.

5. The electronic differential control method for a heavy shuttle car according to claim 4, characterized in that In step S6, the calculation formula for the actual given rotation speed of the inner wheel and outer wheel of the target shuttle is: Where, 、 are the actual given speeds of the inner and outer wheels respectively; 、 are the differential coefficients of the inner and outer wheels respectively; is the center distance between the front and rear tires; is the center distance between the left and right tires; is the steering angle of the target shuttle; is the initial given speed of the target shuttle during the turning phase.

6. The electronic differential control method for a heavy shuttle car according to claim 5, characterized in that : During the turning phase of the target shuttle, the wheels in the same direction as the turning direction are the inner wheels, and the wheels in the opposite direction are the outer wheels.

7. An electronic differential control device for a heavy-duty shuttle vehicle, based on the electronic differential control method for a heavy-duty shuttle vehicle according to any one of claims 1 to 6, characterized in that: It includes a first acquisition module, a first determination module, a second acquisition module, a second determination module, a third determination module and a first control module; The first acquisition module is configured to acquire the accelerator pedal opening of the target shuttle during the steering phase, and the first determination module is configured to determine the initial given rotational speed of the target shuttle during the steering phase based on the first mapping relationship. The second acquisition module is configured to acquire the displacement length of the cylinder based on the cylinder displacement sensor, and the second determination module is configured to determine the steering angle of the target shuttle during the steering phase based on the second mapping relationship and in combination with the mechanical structure of the target shuttle. The third determination module is used to determine the turning radius and the differential speed coefficient between the inner and outer wheels of the target shuttle vehicle based on the steering angle and the distance between the front and rear tires and the left and right tires of the target shuttle vehicle. Finally, the actual given speed of the inner and outer wheels of the target shuttle vehicle is determined based on the preliminary given speed. The first control module is used to control the inner and outer wheel motors to output the final actual given speed.

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