Control method for pure electric mining dump truck

Abstract

A control method of a pure electric mining dump truck comprises the steps of (1) pipeline control, (2) traction control, (2.1) a climbing mode, (2.2) a normal mode, (2.3) a downhill mode, (2.4) a reversing mode and (2.5) hill start, and (3) brake control, (3.1) hill brake, (3.2) conventional brake, (3.3) rapid brake and (3.4) emergency brake, wherein the traction control includes (2.1) a climbing mode, (2.2) a normal mode, (2.3) a downhill mode, (2.4) a reversing mode and (2.5) hill start; and the brake control includes (3.1) hill brake, (3.2) conventional brake, (3.3) rapid brake and (3.4) emergency brake. Electro-pneumatic combined braking is used as design logic and guidance, the problems of stalling, insufficient electric braking and the like during hill starting and heavy-load downhill of the vehicle are solved, meanwhile, the operation difficulty of a driver is lowered, and the safety performance and the operation efficiency of the vehicle are improved.

Description

Technical Field

[0001] The invention relates to the technical field of dump trucks, in particular to a control method for a pure electric mining dump truck. Background Art

[0002] Due to the complex working conditions in mines and the busy transportation work, drivers will not downshift or slow down as required when going downhill, which may easily cause the motor to overspeed and the motor cannot shift into gear. At the same time, heavy-loaded vehicles cannot start on a slope. Drivers need to step on the accelerator and brake at the same time to start, and release the handbrake to start after feeling sufficient traction. This requires high operation from the driver and poses a considerable safety risk. Therefore, it is very important to add the braking logic and slope stop and start functions to pure electric mining dump trucks. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a control method for a pure electric mining dump truck, which improves the control logic of the whole vehicle without affecting the performance of the original pure electric dump truck, assists the driver in making operational judgments, and avoids accidents such as unsuccessful gear shifting when going downhill with a heavy load, motor overspeed, and insufficient traction when starting on a slope.

[0004] In order to solve the above technical problems, the technical solution of the present invention is: a control method for a pure electric mining dump truck, comprising:

[0005] (1) Pipeline control: The air from the air compressor enters the primary air tank through pipeline A and the one-way valve. The four-way valve is connected to the primary air tank, the safety valve and the pressure sensor respectively. The vehicle controller VCU controls the operation of the air compressor by monitoring the pressure sensor data. When the vehicle controller VCU detects that the air pressure is too high, the air compressor stops working. When the air pressure is too low, the air compressor starts. When driving, the hand brake valve handle is in the release position. Pipeline C5 continuously supplies air from the primary air tank to the hand brake valve, so that its interfaces 1 and 2 have air. The air from the brake air tank is inflated to the locking hole through the synchronization valve and pipeline. As long as the air pressure in the locking hole is above 4.5 bar, the locking mechanism in the brake cylinder will be released.

[0006] (2) Traction control: Traction control determines the target torque output and upper limit required for the working condition by detecting the vehicle's real-time slope data. The traction mode is automatically selected according to the vehicle's current driving slope:

[0007] (2.1) Climbing mode: When the slope angle α>2°, the vehicle torque output upper limit is automatically adjusted to the highest;

[0008] (2.2) Normal mode: When the slope angle is -2°≤α≤2°, the speed limit is 25km / h;

[0009] (2.3) Downhill mode: When the slope angle α<-2°, the vehicle is judged to be going downhill. The vehicle controller VCU calculates the required braking force based on the speed and acceleration. If the required braking force is less than the maximum electric braking force, the air brake is not enabled, and the speed is adjusted by switching the electric brake handle. If the electric brake handle is turned to the 5th gear, the vehicle controller VCU calculates that the required braking force is still greater than the maximum electric braking force. At this time, the vehicle controller VCU outputs a PWM signal to control the opening and closing of the solenoid valve, and the air brake makes up for the insufficient electric braking force.

[0010] (2.4) Reverse mode: When the steering handle is in the backward direction, the speed limit is 10km / h;

[0011] (2.5) Slope start: When the vehicle stops on a slope, the parking brake and air brake are applied to the vehicle at the same time. When the driver releases the handbrake, the foot brake valve closes, and the emergency relay valve cuts off the air supply to the brake cylinder. The air in pipelines M, M1, M2 and B can be discharged by the foot brake valve. The air in pipeline L is discharged through the dry / wet circuit control valve, and the air in pipeline M3 is discharged through the quick release valve. The air in the brake cylinder pipelines K2, K3 and pipelines G3, G4 is discharged through the emergency relay valve. The parking brake is released, and the air brake is still applied. Move the steering handle and use the accelerator pedal to increase the motor torque. When the vehicle controller VCU calculates that the driving force is greater than the friction force, the solenoid valve automatically closes, the brake is released, and the slope start is achieved.

[0012] (3) Braking control:

[0013] (3.1) Slope braking: When the vehicle stops on a slope, press the brake pedal to apply air brake. After the vehicle stops on the slope, pull the handbrake and release the brake;

[0014] (3.2) Conventional braking: When the calculated required braking force is much less than the maximum electric braking force, it is judged as conventional braking. When the vehicle speed is less than 5 km / h, only air braking is involved; when the vehicle speed is greater than 5 km / h, electric braking is involved; the working brake can be applied to all wheels by stepping on the foot brake valve. Stepping on the foot brake valve guides air through pipes M, M1, M2, L, M3 and B to act on the emergency relay valve, which is released by the emergency relay valve. The air passes through pipes G3 and G4 and pipes K2 and K3 to the brake cylinder to implement working braking;

[0015] (3.3) Rapid braking: When the required braking force is calculated to be close to or greater than the maximum electric braking force, it is judged as rapid braking, the electric brake is applied to the maximum, and the brake pedal controls the air brake to be applied quickly; if the vehicle needs to be decelerated urgently during operation and the driver does not step on the foot brake valve, the electronically controlled one-way valve will perform proportional braking on this circuit, replacing the foot brake valve to achieve working braking;

[0016] (3.4) Emergency brake: When the emergency button is pressed, emergency brake, air brake and electric brake are applied to the maximum.

[0017] As an improvement, the traction, resistance, and sliding force are calculated as follows:

[0018] The traction force is converted by the actual vehicle torque and calculated according to formula 3-1:

[0019]

[0020] Where M is the torque, μ c is the transmission ratio of the reducer, μ d is the gear ratio, η is the mechanical transmission efficiency, r is the radius of the tire rolling circle, and the real-time resistance of the vehicle is calculated using formula 3-2;

[0021]

[0022] The downhill sliding force is calculated by formula 3-3

[0023]

[0024] Where m is the current mass of the vehicle, g is the acceleration of gravity, i is the slope, μ is the rolling resistance coefficient, CD is the air resistance coefficient, A is the frontal area, and v is the current vehicle speed.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] Based on the design principles of logic and fault-oriented safety involved in the electric-pneumatic combined braking of EMUs, an electric-pneumatic combined braking system for mining vehicles is developed. Through the real-time data analysis and processing of roads and vehicles by the controller, electric braking is mainly used, and air braking and electric braking are used to supplement each other to solve the technical problems currently encountered by the electric mining truck industry: 1. The vehicle's climbing and shifting logic is not smooth, and the shifting is unsuccessful; 2. The electric braking force of the vehicle is insufficient when it is heavily loaded downhill; 3. The motor of the vehicle is overspeeding when it is heavily loaded downhill; 4. The starting gear does not match the traction force when it is halfway up the slope; 5. The electric braking performance is reduced due to aging of batteries in long-term service, etc.; 6. Automatic braking is achieved for major faults. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is the pipeline principle diagram of the present invention.

[0028] Figure 2 This is the traction control logic diagram.

[0029] Figure 3 This is the brake control logic diagram. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings.

[0031] A control method for a pure electric mining dump truck, comprising:

[0032] (1) Figure 1 As shown, pipeline control: air from the air compressor 4 enters the primary air tank 10 through the pipeline A and the one-way valve 9, the four-way valve is respectively connected to the primary air tank 10, the safety valve 11 and the pressure sensor 5, and the vehicle controller VCU controls the operation of the air compressor 4 by monitoring the pressure sensor data. When the vehicle controller VCU detects that the air pressure is too high, the air compressor 4 stops working, and when the air pressure is too low, the air compressor 4 starts; when driving, the handle of the hand brake valve 1 is in the release position, and the pipeline C5 continuously supplies air from the primary air tank 10 to the hand brake valve 1, so that its interfaces 1 and 2 have air, and the air coming out of the rear brake air tank 12, 13 and the front brake air tank 18 is inflated to the locking hole through the synchronization valve 15 and the pipelines H3, H4 and the pipelines Jl, J2. As long as the air pressure in the locking hole is above 4.5 bar, the locking mechanism in the brake cylinders 16 and 19 will be released.

[0033] (2) Figure 2 As shown, traction control: traction control determines the target torque output and upper limit required for the working condition by detecting the real-time slope data of the vehicle. The traction mode is automatically selected according to the current driving slope of the vehicle:

[0034] (2.1) Climbing mode: When the slope angle α>2°, the vehicle torque output upper limit is automatically adjusted to the highest;

[0035] (2.2) Normal mode: When the slope angle is -2°≤α≤2°, the speed limit is 25km / h;

[0036] (2.3) Downhill mode: When the slope angle α<-2°, the vehicle is judged to be going downhill. The vehicle controller VCU calculates the required braking force based on the speed and acceleration. If the required braking force is less than the maximum electric braking force, the air brake is not enabled, and the speed is adjusted by switching the electric brake handle. If the electric brake handle is turned to the 5th gear, the vehicle controller VCU calculates that the required braking force is still greater than the maximum electric braking force. At this time, the vehicle controller VCU outputs a PWM signal to control the opening and closing of the solenoid valve, and the air brake makes up for the insufficient electric braking force.

[0037] (2.4) Reverse mode: When the steering handle is in the backward direction, the speed limit is 10km / h;

[0038] (2.5) Slope start: When the vehicle stops on a slope, the parking brake and air brake are applied to the vehicle at the same time. When the driver releases the handbrake, the foot brake valve closes, and the emergency relay valve 17 cuts off the air supply to the brake cylinders 16 and 19. The air in pipelines M, M1, M2 and B can be discharged by the foot brake valve 2. The air in pipeline L is discharged through the dry / wet circuit control valve 8, and the air in pipeline M3 is discharged through the quick release valve 6. The air in the brake cylinder pipelines K2, K3 and pipelines G3, G4 is discharged through the emergency relay valve 17. The parking brake is released, but the air brake is still applied. Move the steering handle and use the accelerator pedal to increase the motor torque. When the vehicle controller VCU calculates that the driving force is greater than the friction force, the solenoid valve automatically closes, the brake is released, and a slope start is achieved.

[0039] (3) Figure 3 As shown in the figure, braking control: vehicle braking is controlled by the brake pedal and the electric brake handle. The electric brake handle has 5 gears to control the strength of electric brake recovery. When the electric brake force is insufficient due to battery overheating, high battery power, battery aging, etc., the vehicle controller VCU calculates the air brake force that needs to be supplemented at this time, and controls the duty cycle of the PWM signal to achieve equivalent control of the solenoid valve opening. When the vehicle is driving on flat ground, the electric brake is decelerated by adjusting the gear of the electric brake handle, and finally the brake is lightly pressed to stop; when the vehicle is downhill, if the required braking force is less than the maximum electric braking force, the air brake is not enabled, and the speed is adjusted by switching the electric brake handle gear; if the electric brake handle is turned to the 5th gear, the vehicle controller VCU calculates that the required braking force is still greater than the maximum electric braking force. At this time, the vehicle controller VCU outputs a PWM signal to control the opening and closing of the solenoid valve, and the air brake is used to make up for the insufficient electric braking force. The braking category is divided into conventional braking, rapid braking and emergency braking according to the current driving conditions of the vehicle. The emergency braking is controlled by the emergency brake button, and the button can be pressed for emergency braking in an emergency.

[0040] (3.1) Slope braking: When the vehicle stops on a slope, press the brake pedal to apply air brake. After the vehicle stops on the slope, pull the handbrake and release the brake;

[0041] (3.2) Conventional braking: When the calculated required braking force is much smaller than the maximum electric braking force, it is judged as conventional braking. When the vehicle speed is less than 5 km / h, only air braking is involved; when the vehicle speed is greater than 5 km / h, electric braking is involved; the working brake can be applied to all wheels by stepping on the foot brake valve 2. Stepping on the foot brake valve 2 guides the air through the pipelines M, M1, M2, L, M3 and B to act on the emergency relay valve 17, which is released by the emergency relay valve 17. The air passes through the pipelines G3 and G4 and the pipelines K2 and K3 to the brake cylinder to implement the working brake;

[0042] (3.3) Rapid braking: When the required braking force is calculated to be close to or greater than the maximum electric braking force, it is judged as rapid braking, the electric brake is applied to the maximum, and the brake pedal controls the air brake to be applied quickly; if the vehicle needs to be decelerated urgently during operation and the driver does not step on the foot brake valve, the electronically controlled one-way valve will perform proportional braking on this circuit, replacing the foot brake valve to achieve working braking;

[0043] (3.4) Emergency brake: When the emergency button is pressed, emergency brake, air brake and electric brake are applied to the maximum.

[0044] The traction, resistance and sliding force are calculated as follows:

[0045] The traction force is converted by the actual vehicle torque and calculated according to formula 3-1:

[0046]

[0047] Where M is the torque, μ c is the transmission ratio of the reducer, μ d is the gear ratio, η is the mechanical transmission efficiency, r is the radius of the tire rolling circle, and the real-time resistance of the vehicle is calculated using formula 3-2;

[0048]

[0049] The downhill sliding force is calculated by formula 3-3

[0050]

[0051] Where m is the current mass of the vehicle, g is the acceleration of gravity, i is the slope, μ is the rolling resistance coefficient, CD is the air resistance coefficient, A is the frontal area, and v is the current vehicle speed.

Claims

1. A control method for a pure electric mining dump truck, characterized in that: include: (1) Pipeline control: The air from the air compressor enters the primary air tank through pipeline A and the one-way valve. The four-way valve is connected to the primary air tank, the safety valve and the pressure sensor respectively. The vehicle controller VCU controls the operation of the air compressor by monitoring the pressure sensor data. When the vehicle controller VCU detects that the air pressure is too high, the air compressor stops working. When the air pressure is too low, the air compressor starts. When driving, the hand brake valve handle is in the release position. Pipeline C5 continuously supplies air from the primary air tank to the hand brake valve, so that its interfaces 1 and 2 have air. The air from the brake air tank is inflated to the locking hole through the synchronization valve and pipeline. As long as the air pressure in the locking hole is above 4.5 bar, the locking mechanism in the brake cylinder will be released. (2) Traction control: Traction control determines the target torque output and upper limit required for the working condition by detecting the vehicle's real-time slope data. The traction mode is automatically selected according to the vehicle's current driving slope: (2.1) Climbing mode: When the slope angle α>2°, the vehicle torque output upper limit is automatically adjusted to the highest; (2.2) Normal mode: When the slope angle is -2°≤α≤2°, the speed limit is 25km / h; (2.3) Downhill mode: When the slope angle α<-2°, the vehicle is judged to be going downhill. The vehicle controller VCU calculates the required braking force based on the speed and acceleration. If the required braking force is less than the maximum electric braking force, the air brake is not enabled, and the speed is adjusted by switching the electric brake handle. If the electric brake handle is turned to the 5th gear, the vehicle controller VCU calculates that the required braking force is still greater than the maximum electric braking force. At this time, the vehicle controller VCU outputs a PWM signal to control the opening and closing of the solenoid valve, and the air brake makes up for the insufficient electric braking force. (2.4) Reverse mode: When the steering handle is in the backward direction, the speed limit is 10km / h; (2.5) Slope start: When the vehicle stops on a slope, the parking brake and air brake are applied to the vehicle at the same time. When the driver releases the handbrake, the foot brake valve closes, and the emergency relay valve cuts off the air supply to the brake cylinder. The air in pipelines M, M1, M2 and B can be discharged by the foot brake valve. The air in pipeline L is discharged through the dry / wet circuit control valve, and the air in pipeline M3 is discharged through the quick release valve. The air in the brake cylinder pipelines K2, K3 and pipelines G3, G4 is discharged through the emergency relay valve. The parking brake is released, and the air brake is still applied. Move the steering handle and use the accelerator pedal to increase the motor torque. When the vehicle controller VCU calculates that the driving force is greater than the friction force, the solenoid valve automatically closes, the brake is released, and the slope start is achieved. (3) Braking control: (3.1) Slope braking: When the vehicle stops on a slope, press the brake pedal to apply air brake. After the vehicle stops on the slope, pull the handbrake and release the brake; (3.2) Conventional braking: When the calculated required braking force is much less than the maximum electric braking force, it is judged as conventional braking. When the vehicle speed is less than 5 km / h, only air braking is involved; when the vehicle speed is greater than 5 km / h, electric braking is involved; the working brake can be applied to all wheels by stepping on the foot brake valve. Stepping on the foot brake valve guides air through pipes M, M1, M2, L, M3 and B to act on the emergency relay valve, which is released by the emergency relay valve. The air passes through pipes G3 and G4 and pipes K2 and K3 to the brake cylinder to implement working braking; (3.3) Rapid braking: When the required braking force is calculated to be close to or greater than the maximum electric braking force, it is judged as rapid braking, the electric brake is applied to the maximum, and the brake pedal controls the air brake to be applied quickly; if the vehicle needs to be decelerated urgently during operation and the driver does not step on the foot brake valve, the electronically controlled one-way valve will perform proportional braking on this circuit, replacing the foot brake valve to achieve working braking; (3.4) Emergency brake: When the emergency button is pressed, emergency brake, air brake and electric brake are applied to the maximum.

2. A control method for a pure electric mining dump truck according to claim 1, characterized in that: The traction force is converted by the actual vehicle torque and calculated according to formula 3-1: Where M is the torque, μ C is the transmission ratio of the reducer, μ d is the gear ratio, η is the mechanical transmission efficiency, r is the radius of the tire rolling circle, and the real-time resistance of the vehicle is calculated using formula 3-2; The downhill sliding force is calculated by formula 3-3 Where m is the current mass of the vehicle, g is the acceleration of gravity, i is the slope, μ is the rolling resistance coefficient, CD is the air resistance coefficient, A is the frontal area, and v is the current vehicle speed.

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