A control method for a heavy-duty four-motor four-wheel drive articulated vehicle for mining

Abstract

The present invention belongs to the technical field of trackless auxiliary transportation equipment in underground coal mines, and discloses a control method for a heavy-duty front and rear four-motor four-wheel drive articulated vehicle for mining, including a steering control method and a walking control method, wherein the steering control method comprises the following steps: S101, receiving given steering angle information; S102, calculating the required extension of the right steering cylinder and the left steering cylinder according to the given steering angle; S103, driving the corresponding cylinder to extend or retract until the extension reaches the requirement; the walking control method comprises the following steps: S201, receiving accelerator pedal opening information; S202, determining the given vehicle speed of the whole vehicle and the given rotation speed of the front drive main motor and the rear drive main motor according to the accelerator pedal opening; S203, calculating the power coefficient of the rear drive main and slave motors; S204, judging the vehicle state according to the power coefficient of the rear drive main and slave motors, and determining the initial given torque of each motor according to the vehicle state. The present invention can reduce the total power consumption of the whole vehicle and improve the cruising range of the battery vehicle.

Description

Technical Field

[0001] The invention relates to a control method for a heavy-duty front and rear four-motor four-wheel drive articulated vehicle for mining, belonging to the technical field of trackless auxiliary transportation equipment in coal mines. Background Art

[0002] Heavy-duty articulated transport vehicles for mining are one of the underground mobile transport equipment. With the continuous promotion of new energy technologies, heavy-duty transport vehicles that rely on motors as driving technology have been continuously developed.

[0003] Many new energy vehicles use a single motor plus front and rear axle drive technology or distributed four-wheel side drive technology. When a single motor is used as the drive system, the motor has high power and occupies a large size. At the same time, the heat generated by the high-power motor brings new problems to heat dissipation. When using distributed four-wheel side drive, the motors are dispersed around the tires. The driving power of a single motor is small, but the deviation of the synchronous control and differential strategy leads to excessive parasitic power, which puts high requirements on the synchronous control and differential control between different motors.

[0004] At present, in terms of vehicle control, pressure sensors are often used to judge the no-load, light-load and heavy-load conditions, and then the given torque is determined according to the load conditions. Therefore, how to judge the load condition of the vehicle without using pressure sensors, and how to adopt different control strategies for different load conditions are problems that need to be solved urgently. Summary of the invention

[0005] The present invention overcomes the deficiencies of the prior art and aims to solve the following technical problems: providing a control method for a heavy-duty four-motor four-wheel drive articulated vehicle for mining, so as to realize changes in vehicle control strategy with load, reduce energy consumption, and increase vehicle cruising range.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a control method for a heavy-duty front and rear four-motor four-wheel drive articulated vehicle for mining, the vehicle comprising: a front frame and a rear frame, the front frame and the rear frame are articulated by a slewing bearing, and are also connected by a right steering cylinder and a left steering cylinder, the front wheels arranged on the front frame are driven by a front drive main motor and a front drive slave motor, and the rear wheels arranged on the rear frame are driven by a rear drive main motor and a rear drive slave motor, the control method comprises a steering control method and a walking control method, and the steering control method comprises the following steps:

[0007] S101, receiving given steering angle information;

[0008] S102, calculating the required extension of the right steering cylinder and the left steering cylinder according to a given steering angle;

[0009] S103, driving the corresponding oil cylinder to extend or retract until the extension reaches the required amount;

[0010] The walking control method comprises the following steps:

[0011] S201, receiving accelerator pedal opening information;

[0012] S202, determining a given vehicle speed and given rotation speeds of the front drive main motor and the rear drive main motor according to the accelerator pedal opening; determining upper speed limits of the front drive main motor and the front drive slave motor, and upper speed limits of the rear drive main motor and the rear drive slave motor according to the given rotation speeds of the front drive main motor and the rear drive main motor;

[0013] S203, calculating the power coefficients of the rear drive master and slave motors according to the input voltages and currents of the rear drive master motor and the rear drive slave motor;

[0014] S204, judging the vehicle state according to the power coefficient of the rear drive master and slave motors and determining the initial given torque of each motor according to the vehicle state; the specific method is:

[0015] If it is unloaded, the front wheel main motor and the front wheel slave motor will not participate in the control; the rear drive main motor and the rear drive slave motor are both controlled in the torque closed-loop mode, and the initial given torque of the rear drive main motor is the rated torque T n , the rear drive starts from the motor with a constant initial torque of -10%T n ;

[0016] If the load is light, the rear drive main motor and the rear drive slave motor are both controlled in a torque closed-loop mode, and their initial given torque is determined according to the accelerator pedal opening and the corresponding torque curve; the front drive main motor and the front drive slave motor are both controlled in a torque closed-loop mode, and their initial given torque is determined according to the accelerator pedal opening and the corresponding torque curve;

[0017] If the load is heavy, the front drive main motor, front drive slave motor, rear drive main motor and rear drive slave motor are all controlled in torque closed loop mode, and the speed is less than the rated speed n n , the maximum motor torque T in the speed torque database max As the initial given torque of each motor;

[0018] In the torque closed-loop mode, the real-time given torque of the motor is adjusted by the torque adjustment coefficient.

[0019] In step S202, the calculation formula for the given rotation speed of the front driving main motor and the rear driving main motor is:

[0020] n motor_demand1 =n max1 ×A acc ;

[0021] n motor_demand2 =n max2×A acc ;

[0022] Among them, n motor_demand1 and n motor_demand2 Respectively represent the given speed of the front drive main motor and the rear drive main motor, A acc is the pedal opening, n max1 and n max2 Respectively represent the maximum given speeds of the front drive main motor and the rear drive main motor;

[0023] The upper limit of the speed of the front drive main motor is equal to the given speed of the front drive main motor, and the upper limit of the speed of the front drive slave motor is equal to the actual speed of the front drive active motor;

[0024] The upper limit of the speed of the rear drive main motor is equal to the given speed of the rear drive main motor, and the upper limit of the speed of the rear drive slave motor is equal to the actual speed of the rear drive main motor.

[0025] In step S203, the calculation formula of the power coefficient of the rear drive master and slave motors is:

[0026]

[0027] Among them, U 8-1 ,I 8-1 is the input voltage and current of the rear wheel main motor driver, U 8-2 ,I 8-2 is the input voltage and current of the rear wheel motor driver, P n Indicates the rated power of the rear drive master / slave motor.

[0028] In step S204, the calculation formula of the torque adjustment coefficient is:

[0029]

[0030] Among them, K m represents the torque adjustment coefficient, I represents the actual output current of the motor, and I n Indicates the rated current of the motor;

[0031] In the torque closed-loop mode, the real-time given torque of the motor is adjusted by the torque adjustment coefficient. The specific method is: the product of the motor torque adjustment coefficient and the initial given torque is used as the motor given torque to adjust the motor torque.

[0032] The calculation formula for the elongation of the left steering cylinder and the right steering cylinder is:

[0033]

[0034]

[0035] Wherein, AC represents the required elongation of the piston of the left steering cylinder, AC' represents the required elongation of the piston of the right steering cylinder, OA and OB represent the distances between the slewing bearing and the two fixed ends of the left steering cylinder, OA' and OB' represent the distances between the slewing bearing and the two fixed ends of the right steering cylinder, θ represents the steering angle of the whole vehicle, α and β represent the half angles of the front frame and the rear frame respectively; BC and B'C' represent the original lengths of the left steering cylinder and the right steering cylinder respectively.

[0036] In step S103, a steering angle threshold δ is set, and when the following conditions are met, it is considered that the steering requirement is met:

[0037]

[0038] Among them, L0 represents the required extension of the cylinder, and L represents the actual extension of the cylinder.

[0039] The specific method for judging the vehicle status according to the power coefficient of the rear drive master and slave motors is:

[0040] If the power factor of the rear drive master and slave motors is less than the no-load factor, it is no-load;

[0041] If the power factor of the rear drive master and slave motors is greater than or equal to the no-load factor and less than the light-load factor, it is light-loaded;

[0042] If the power factor of the rear drive master and slave motors is greater than or equal to the light load factor, it is considered heavy load.

[0043] The no-load factor is K p1 =0.5, the light load factor is K p2 =0.75.

[0044] The control method of a heavy-duty mining front and rear four-motor four-wheel drive articulated vehicle also includes the following steps: S200, establishing a motor speed torque database table, determining the motor constant torque working area and constant power working area, determining the rated speed n N , maximum speed n max , rated torque T n and maximum torque T max .

[0045] In step S204, the torque curves corresponding to the rear drive main motor and the front drive main motor are:

[0046] B1=T n , A acc <k;

[0047] B1=T n +(T max -T n )(A acc-k) / (100-k), A acc ≥k;

[0048] The torque curves corresponding to the front drive slave motor and the front drive slave motor are:

[0049] A1=-0.1T n , A acc <k;

[0050] A1=-0.1T n +[(0.1T n ) 2 -(A acc -k) 2 ] 0.5 , k≤A acc <c;

[0051] A1=-0.1T n +[(0.1T n ) 2 -(ck) 2 ] 0.5 +(T max -[(0.1T n ) 2 -(Ck) 2 ] 0.5 )(A acc -c) / (100-c),

[0052] c≤A acc <100;

[0053] Among them, B1 represents the torque value corresponding to the rear drive main motor and the front drive main motor, T n Indicates rated torque, T max Indicates the maximum torque, A acc represents the accelerator pedal opening, k represents the accelerator pedal opening threshold, A1 represents the torque value corresponding to the front drive slave motor and the front drive slave motor, and an arc is drawn with A'(k, 0) as the center and 0.1Tn as the radius, passing through D(100, T max ) The horizontal coordinate of the intersection point C of the arc with the tangent of the arc is c.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] 1. The present invention provides a control method for a heavy-duty mining articulated vehicle with four front and rear motors and four-wheel drive, which can solve the shortcomings of large motor size and high power when a heavy-duty vehicle is driven by a single motor. The dispersed arrangement of the four motors facilitates power distribution and heat dissipation of the motors. At the same time, it is easier to synchronize and control than wheel-side direct-drive motors and has higher reliability.

[0056] 2. The present invention determines the load condition of the whole vehicle through the power coefficient of the rear drive master and slave motors, determines the initial given torque of the four motors according to the given motor speed, combined with the speed torque database and the load condition; adjusts the given torque through the torque adjustment coefficient, so that the vehicle has strong controllability and stronger endurance. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 A top view of a heavy-duty front and rear four-motor four-wheel drive articulated vehicle for mining in an embodiment of the present invention;

[0058] Figure 2 It is a schematic diagram of the steering angle and the telescopic length L of the oil cylinder;

[0059] Figure 3 is a schematic diagram of a flow chart of a steering control in an embodiment of the present invention;

[0060] Figure 4 The distribution diagram of the power coefficient and load condition of the front and rear motors;

[0061] Figure 5 This is the motor torque control diagram when no-load;

[0062] Figure 6 This is the motor torque control diagram under light load;

[0063] Figure 7 This is the motor torque control diagram when it is overloaded;

[0064] Figure 8 It is the motor given torque adjustment coefficient diagram;

[0065] In the figure: 1 is the front wheel, 2 is the front wheel differential, 3 is the front wheel speed reducer, 4 is the front frame, 5-1 is the front drive main motor, 5-2 is the front drive slave motor, 6 is the slewing bearing, 7-1 is the right steering cylinder, 7-2 is the left steering cylinder, 8-1 is the rear drive main motor, 8-2 is the rear drive slave motor, 9 is the rear frame, 10 is the rear wheel speed reducer, 11 is the rear wheel differential, and 12 is the rear wheel. DETAILED DESCRIPTION

[0066] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0067] Embodiment 1 of the present invention provides a control method for a heavy-duty front and rear four-motor four-wheel drive articulated vehicle for mining, the vehicle comprising: the vehicle comprising: a front frame 4 and a rear frame 9, the front frame 4 and the rear frame 9 are articulated through a slewing bearing 6, and are also connected through a right steering cylinder 7-1 and a left steering cylinder 7-2, the front wheel 1 arranged on the front frame 4 is driven by a front drive main motor 5-1 and a front drive slave motor 5-2, and the rear wheel 12 arranged on the rear frame 9 is driven by a rear drive main motor 8-1 and a rear drive slave motor 8-2. The motor parameters of the front drive main motor, the slave motor and the rear drive main motor and the slave motor are consistent.

[0068] The rear drive main motor 8-1 and the rear drive slave motor 8-2 drive the rear wheel 12 through the rear wheel reducer 10 and the rear wheel differential 11. The front drive main motor 5-1 and the front drive slave motor 5-2 drive the front wheel 1 through the front wheel reducer 3 and the front wheel differential 2. The cylinder barrels of the right steering cylinder 7-1 and the left steering cylinder 7-2 are fixed to the rear frame, and the pistons are fixed to the front frame; the outer ring of the slewing bearing 6 is fixed to the front frame, and the inner ring is fixed to the rear frame. When the vehicle turns, the front and rear frames are driven around the slewing bearing by the extension and contraction of the two steering cylinder pistons. When the vehicle is moving straight or turning, the extended length of the steering cylinder piston remains at a certain position.

[0069] The control method of this embodiment includes a steering control method and a walking control method, and the steering control method comprises the following steps:

[0070] S101, receiving given steering angle information;

[0071] S102, calculating the required extension of the right steering cylinder 7-1 and the left steering cylinder 7-2 according to a given steering angle;

[0072] S103, driving the corresponding oil cylinder to extend or retract until the extension reaches the requirement.

[0073] like Figure 2 As shown, AC represents the required extension of the piston of the left steering cylinder, AC' represents the required extension of the piston of the right steering cylinder, OA and OB represent the distances between the slewing bearing 6 and the two fixed ends of the left steering cylinder 7-2, OA' and OB' represent the distances between the slewing bearing 6 and the two fixed ends of the right steering cylinder 7-1, θ represents the steering angle of the whole vehicle, α and β represent the half angles of the front frame and the rear frame respectively; BC and B'C' represent the original lengths of the left steering cylinder 7-2 and the right steering cylinder 7-1 respectively. According to the spatial geometric relationship, it can be known that:

[0074]

[0075]

[0076] In step S103, the hydraulic circuit of the oil cylinder is controlled by a manual pilot valve to drive the oil cylinder to extend or retract.

[0077] In addition, in step S103, a steering angle threshold δ is set, and when the following conditions are met, it is considered that the steering requirement is met:

[0078]

[0079] Among them, L0 represents the required extension of the cylinder, and L represents the actual extension of the cylinder.

[0080] Furthermore, in this embodiment, it is detected whether the test data of the left oil cylinder piston displacement sensor is normal. Figure 3 As shown in the figure, if the test data of the left cylinder piston displacement sensor is normal, the left cylinder piston extension position L is measured by the left cylinder piston displacement sensor to see whether it meets the target requirement. Set the cylinder steering threshold δ%, when If the steering does not meet the requirements, The left steering cylinder is extended and the right steering cylinder is retracted by the manual pilot valve. The manual pilot valve is used to control the retraction of the left steering cylinder piston and the extension of the right steering cylinder piston.

[0081] Furthermore, if the test data of the left cylinder piston displacement sensor is abnormal, check whether the test data of the right cylinder piston displacement sensor is normal. If the test data of the right cylinder piston displacement sensor is normal, measure whether the right cylinder piston extension position L' meets the target requirement through the right cylinder piston displacement sensor. Set the cylinder steering threshold δ%, when If the steering does not meet the requirements, The manual pilot valve is used to control the left steering cylinder piston to retract and the right steering cylinder piston to extend. The left steering cylinder piston is extended and the right steering cylinder piston is retracted through the electromagnetic pilot valve.

[0082] Furthermore, if the test data of the right cylinder piston displacement sensor is abnormal and a fault is reported, the vehicle cannot be used.

[0083] The walking control method comprises the following steps:

[0084] S200, establish a motor speed torque database table, determine the motor constant torque working area and constant power working area, determine the rated speed n N , maximum speed n max , rated torque T n and maximum torque T max .

[0085] S201, receiving accelerator pedal opening information;

[0086] S202, determining a given vehicle speed and a given rotational speed of the front drive main motor and the rear drive main motor according to the accelerator pedal opening; determining an upper limit of the rotational speed of the front drive main motor and the front drive slave motor, and an upper limit of the rotational speed of the rear drive main motor and the rear drive slave motor according to the given rotational speed of the front drive main motor and the rear drive main motor.

[0087] In step S202, the calculation formula for the given rotation speed of the front driving main motor and the rear driving main motor is:

[0088] n motor_demand1 = n max1 ×A acc ; (1)

[0089] n motor_demand2 = n max2 ×A acc ; (2)

[0090] Among them, n motor_demand1 and n motor_demand2 Respectively represent the given speed of the front drive main motor and the rear drive main motor, A acc is the pedal opening, n max1 and n max2 They respectively represent the maximum given speeds of the front drive main motor and the rear drive main motor.

[0091] The upper limit of the speed of the front drive main motor is equal to the given speed of the front drive main motor, and the upper limit of the speed of the front drive slave motor is equal to the actual speed of the front drive active motor;

[0092] The upper limit of the speed of the rear drive main motor is equal to the given speed of the rear drive main motor, and the upper limit of the speed of the rear drive slave motor is equal to the actual speed of the rear drive main motor.

[0093] S203 , calculating the power coefficients of the rear drive master and slave motors according to the input voltages and currents of the rear drive master motor and the rear drive slave motors.

[0094] In step S203, the calculation formula of the power coefficient of the rear drive master and slave motors is:

[0095]

[0096] Among them, U 8-1 ,I 8-1 is the input voltage and current of the rear wheel main motor driver, U 8-2 ,I 8-2 is the input voltage and current of the rear wheel motor driver, P n Indicates the rated power of the rear drive master and slave motors.

[0097] S204: judging the vehicle state according to the power coefficients of the rear drive master and slave motors, and determining the initial given torque of each motor according to the vehicle state.

[0098] like Figure 4 As shown, in step S204, the specific method for judging the vehicle state according to the power coefficient of the rear drive master and slave motors is:

[0099] If the power factor of the rear drive master and slave motors is less than the no-load factor, it is no-load;

[0100] If the power factor of the rear drive master and slave motors is greater than or equal to the no-load factor and less than the light-load factor, it is light-loaded;

[0101] If the power factor of the rear drive master and slave motors is greater than or equal to the light load factor, it is considered heavy load.

[0102] Specifically, the no-load factor is K p1 =0.5, the light load factor is K p2 =0.75.

[0103] Specifically, the specific method for determining the initial given torque of each motor according to the vehicle state is:

[0104] If it is unloaded, the front wheel main motor and the front wheel slave motor will not participate in the control; the rear drive main motor and the rear drive slave motor are both controlled in the torque closed-loop mode, and the initial given torque of the rear drive main motor is the rated torque T n , the rear drive starts from the motor with a constant initial torque of -10%T n ;like Figure 5 shown.

[0105] If the load is light, the rear drive main motor and the rear drive slave motor are both controlled in a torque closed-loop mode, and their initial given torque is determined according to the accelerator pedal opening and the corresponding torque curve; the front drive main motor and the front drive slave motor are both controlled in a torque closed-loop mode, and their initial given torque is determined according to the accelerator pedal opening and the corresponding torque curve.

[0106] like Figure 6 As shown, this is the motor torque control diagram when lightly loaded; when lightly loaded, the rear drive main motor and the front drive main motor are given torque through the first throttle torque curve, and the rear drive slave motor and the front drive slave motor are given torque through the second throttle torque curve.

[0107] When the accelerator pedal opening is less than the accelerator pedal opening threshold k, the rear wheel main motor is given a constant torque T n , the rear wheel is given a constant counter torque from the motor -10% × T n When the pedal opening exceeds k and reaches 100%, the rear wheel main motor gradually increases along the straight line B2D to the maximum motor torque T maxThe rear wheel torque increases gradually from the motor torque given by the motor to the maximum torque T according to curve A2CD. max The curve A2CD consists of two segments, one is the arc A2C and the other is the straight line CD. A2C is centered at A' and 0.1T n An arc with radius tangent to straight lines A1A2 and CD.

[0108] When the accelerator pedal opening is less than the accelerator pedal opening threshold k, the front wheel main motor is given a constant torque T n , the front wheel is given a constant counter torque from the motor -10% × T n When the pedal opening exceeds k and reaches 100%, the front wheel main motor gradually increases along the straight line B2D to the maximum motor torque T max The front wheel torque increases gradually from the motor torque given by the motor according to curve A2CD to the maximum torque T of the motor. max The curve A2CD consists of two segments, one is the arc A2C and the other is the straight line CD. A2C is centered at A' and 0.1T n An arc with radius tangent to straight lines A1A2 and CD.

[0109] That is, in step S204, the torque curves corresponding to the rear drive main motor and the front drive main motor are:

[0110] B1=T n , A acc <k;

[0111] B1=T n +(T max -T n )(A acc -k) / (100-k), A acc ≥k;

[0112] The torque curves corresponding to the front drive slave motor and the front drive slave motor are:

[0113] A1=-0.1T n , A acc <k;

[0114] A1=-0.1T n +[(0.1T n ) 2 -(A acc -k) 2 ] 0.5 , k≤A acc <c;

[0115] A1=-0.1T n +[(0.1T n ) 2 -(ck)2 ] 0.5 +(T max -[(0.1T n ) 2 -(Ck) 2 ] 0.5 )(A acc -c) / (100-c), c≤A acc <100;

[0116] Among them, B1 represents the torque value corresponding to the rear drive main motor and the front drive main motor, T n Indicates rated torque, T max Indicates the maximum torque, A acc represents the accelerator pedal opening, k represents the accelerator pedal opening threshold, A1 represents the torque value corresponding to the front drive slave motor and the front drive slave motor, and an arc is drawn with A'(k, 0) as the center and 0.1Tn as the radius, passing through D(100, T max ) The horizontal coordinate of the intersection point C of the arc with the tangent of the arc is c.

[0117] If the load is heavy, the front drive main motor, front drive slave motor, rear drive main motor and rear drive slave motor are all controlled in torque closed loop mode, and the speed is less than the rated speed n n , that is, the speed of the rear wheel master and slave motors are limited to the low speed working area 0-n n ; The speed of the front wheel master and slave motors are limited to the low speed working area 0-n n ; The maximum motor torque T in the speed torque database max As the initial given torque of each motor, such as Figure 7 shown.

[0118] In the torque closed-loop mode, the real-time given torque of the motor is adjusted by the torque adjustment coefficient.

[0119] In step S204, the calculation formula of the torque adjustment coefficient is:

[0120]

[0121] Among them, Km represents the torque adjustment coefficient, I represents the actual output current of the motor, and I n Indicates the rated current of the motor;

[0122] In the torque closed-loop mode, the real-time given torque of the motor is adjusted by the torque adjustment coefficient. The specific method is: the product of the motor torque adjustment coefficient and the initial given torque is used as the motor given torque to adjust the motor torque. Figure 8 As shown, this is a curve diagram of the motor's given torque adjustment coefficient.

[0123] In summary, the present invention provides a control method for a heavy-duty mining articulated vehicle with four front and rear motors and four-wheel drive, which can solve the shortcomings of large motor size and high power when a heavy-duty vehicle is driven by a single motor. The dispersed arrangement of four motors facilitates the power distribution and heat dissipation of the motor, and is more convenient for synchronous control and has higher reliability than wheel-side direct drive motors. In addition, the present invention determines the load condition of the whole vehicle by the power coefficient of the rear-drive master and slave motors, determines the initial given torque of the four motors according to the given motor speed, combined with the speed torque database and the load condition; adjusts the given torque by the torque adjustment coefficient, so that the vehicle has strong controllability and stronger endurance.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control method for a heavy-duty mining articulated vehicle with four motors and four-wheel drive, characterized in that: The vehicle comprises: a front frame (4) and a rear frame (9), the front frame (4) and the rear frame (9) being articulated via a slewing bearing (6) and connected via a right steering cylinder (7-1) and a left steering cylinder (7-2), the front wheel (1) arranged on the front frame (4) being driven via a front drive main motor (5-1) and a front drive slave motor (5-2), and the rear wheel (12) arranged on the rear frame (9) being driven via a rear drive main motor (8-1) and a rear drive slave motor (8-2), the control method comprising a steering control method and a walking control method, the steering control method comprising the following steps: S101, receiving given steering angle information; S102, calculating the required extension amounts of the right steering cylinder (7-1) and the left steering cylinder (7-2) according to a given steering angle; S103, driving the corresponding oil cylinder to extend or retract until the extension reaches the required amount; The walking control method comprises the following steps: S201, receiving accelerator pedal opening information; S202, determining a given vehicle speed and given rotation speeds of the front drive main motor and the rear drive main motor according to the accelerator pedal opening; determining upper speed limits of the front drive main motor and the front drive slave motor, and upper speed limits of the rear drive main motor and the rear drive slave motor according to the given rotation speeds of the front drive main motor and the rear drive main motor; S203, calculating the power coefficients of the rear drive master and slave motors according to the input voltages and currents of the rear drive master motor and the rear drive slave motor; S204, judging the vehicle state according to the power coefficient of the rear drive master and slave motors and determining the initial given torque of each motor according to the vehicle state; the specific method is: If it is unloaded, the front wheel main motor and the front wheel slave motor will not participate in the control; the rear drive main motor and the rear drive slave motor are both controlled in the torque closed-loop mode, and the initial given torque of the rear drive main motor is the rated torque T n , the rear drive motor initial given torque is constant at -10%T n ; If the load is light, the rear drive main motor and the rear drive slave motor are both controlled in a torque closed-loop mode, and their initial given torque is determined according to the accelerator pedal opening and the corresponding torque curve; the front drive main motor and the front drive slave motor are both controlled in a torque closed-loop mode, and their initial given torque is determined according to the accelerator pedal opening and the corresponding torque curve; If the load is heavy, the front drive main motor, front drive slave motor, rear drive main motor and rear drive slave motor are all controlled in torque closed loop mode, and the speed is less than the rated speed n n , the maximum motor torque T in the speed torque database max As the initial given torque of each motor; In the torque closed-loop mode, the real-time given torque of the motor is adjusted by the torque adjustment coefficient.

2. A control method for a heavy-duty mining articulated vehicle with four motors and four-wheel drive according to claim 1, characterized in that: The upper limit of the speed of the front drive main motor is equal to the given speed of the front drive main motor, and the upper limit of the speed of the front drive slave motor is equal to the actual speed of the front drive active motor; The upper limit of the speed of the rear drive main motor is equal to the given speed of the rear drive main motor, and the upper limit of the speed of the rear drive slave motor is equal to the actual speed of the rear drive main motor.

3. The control method of a heavy-duty mining articulated vehicle with four motors and four-wheel drive according to claim 1 is characterized in that: In step S203, the calculation formula of the power coefficient of the rear drive master and slave motors is: ； Among them, U 8-1 ,I 8-1 is the input voltage and current of the rear wheel main motor driver, U 8-2 ,I 8-2 is the input voltage and current of the rear wheel motor driver, P n Indicates the rated power of the rear drive master / slave motor.

4. The control method of a heavy-duty mining articulated vehicle with four motors and four-wheel drive according to claim 1 is characterized in that: In step S204, the calculation formula of the torque adjustment coefficient is: ； Among them, K m represents the torque adjustment coefficient, I represents the actual output current of the motor, and I n Indicates the rated current of the motor; In the torque closed-loop mode, the real-time given torque of the motor is adjusted by the torque adjustment coefficient. The specific method is: the product of the motor torque adjustment coefficient and the initial given torque is used as the motor given torque to adjust the motor torque.

5. The control method of a heavy-duty mining articulated vehicle with four motors and four-wheel drive according to claim 1 is characterized in that: The calculation formula for the elongation of the left steering cylinder (7-2) and the right steering cylinder (7-1) is: ； ； Wherein, AC represents the required elongation of the piston of the left steering cylinder, AC' represents the required elongation of the piston of the right steering cylinder, OA and OB represent the distances between the slewing bearing (6) and the two fixed ends of the left steering cylinder (7-2), OA' and OB' represent the distances between the slewing bearing (6) and the two fixed ends of the right steering cylinder (7-1), θ represents the steering angle of the whole vehicle, α and β represent the half angles of the front frame and the rear frame respectively; BC and B'C' represent the original lengths of the left steering cylinder (7-2) and the right steering cylinder (7-1), respectively.

6. The control method of a heavy-duty mining articulated vehicle with four motors and four-wheel drive according to claim 1 is characterized in that: In step S103, a steering angle threshold δ is set, and when the following conditions are met, it is considered that the steering requirement is met: Among them, L0 represents the required extension of the cylinder, and L represents the actual extension of the cylinder.

7. The control method of a heavy-duty mining articulated vehicle with four motors and four-wheel drive according to claim 1 is characterized in that: The specific method for judging the vehicle status according to the power coefficient of the rear drive master and slave motors is: If the power factor of the rear drive master and slave motors is less than the no-load factor, it is no-load; If the power factor of the rear drive master and slave motors is greater than or equal to the no-load factor and less than the light-load factor, it is light-loaded; If the power factor of the rear drive master and slave motors is greater than or equal to the light load factor, it is considered heavy load.

8. A control method for a heavy-duty mining articulated vehicle with four motors and four-wheel drive according to claim 7, characterized in that: The no-load factor is K p1 =0.5, the light load factor is K p2 =0.

75.

9. The control method of a heavy-duty mining articulated vehicle with four motors and four-wheel drive according to claim 1, characterized in that: The following steps are also included: S200, establishing a motor speed torque database table, determining the motor constant torque working area and constant power working area, determining the rated speed n N , maximum speed n max , rated torque T n and maximum torque T max .

10. The control method of a heavy-duty mining articulated vehicle with four motors and four-wheel drive according to claim 1, characterized in that: In step S204, the torque curves corresponding to the rear drive main motor and the front drive main motor are: B1=T n ,A acc <k; B1=T n +(T max -T n )(A acc -k) / (100-k), A acc ≥k; The torque curves corresponding to the front drive slave motor and the front drive slave motor are: A1=-0.1T n ,A acc <k; A1=-0.1T n +[(0.1T n ) 2 -(A acc -k) 2 ] 0.5 ,k ≤A acc <c; A1=-0.1T n +[(0.1T n ) 2 -(c-k) 2 ] 0.5 + (T max -[(0.1T n ) 2 -(c-k) 2 ] 0.5 )(A acc -c) / (100-c),c≤A acc <100; Among them, B1 represents the torque value corresponding to the rear drive main motor and the front drive main motor, T n Indicates rated torque, T max Indicates the maximum torque, A acc represents the accelerator pedal opening, k represents the accelerator pedal opening threshold, A1 represents the torque value corresponding to the front drive slave motor and the front drive slave motor, with A'(k,0) as the center, 0.1T n After drawing an arc with radius D(100, T max ) The horizontal coordinate of the intersection point C of the arc with the tangent of the arc is c.

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