Working condition self-adaptive minimum energy consumption control method for electric drive dump truck

Abstract

The invention discloses a working condition self-adaptive minimum energy consumption control method for an electric drive dumper, which comprises the following steps of: acquiring data such as load, accelerator pedal angle, brake pedal angle, ramp angle and motor rotating speed of the dumper through a sensor, and transmitting the data to a whole vehicle controller; a whole vehicle controller calculates and establishes a relation model between an accelerator pedal and a brake pedal and between the accelerator pedal and the brake pedal and between the accelerator pedal and the brake pedal and between the brake pedal and the generated traction force and braking force in real time, and then the optimal traction force and braking force needed when the dumper runs in the minimum energy consumption state are given by adding a minimum energy consumption function of constraint conditions and combining a minimum value principle method. An inverse model is used for calculating the optimal input angle of the pedal when the traction force and the braking force are optimal, and finally, the input value when the accelerator pedal and the brake pedal are at the maximum angle is adjusted to be the optimal input angle of the accelerator pedal and the brake pedal. According to the invention, the dumper can run at the minimum energy consumption state under each working condition, unnecessary traction and braking energy consumption is reduced, the operation of the motor is protected, and the service life of the whole dumper component is prolonged.

Description

Technical Field

[0001] The invention relates to a working condition adaptive minimum energy consumption control method for an electric drive dump truck, belonging to the technical field of engineering machinery. Background Art

[0002] As the main transportation equipment in mines, electric drive dump trucks play a very important role in the engineering machinery industry. The electric drive system technology has been rapidly developed at home and abroad due to its advantages such as high efficiency and low pollution. However, due to the complex structure of engineering machinery itself and the large mechanical friction loss, the energy generated by the engine is very different from the energy that finally drives the dump truck to run. In addition, the interference of the external environment and the improper operation of the driver further waste the energy transmission of the dump truck. In traditional methods, most drivers adjust the operation mode of the dump truck in time according to the actual working conditions of the outside world, so that the dump truck can run with better performance, but accidents are prone to occur in the blind spot of the driver's vision. Sometimes, for the convenience of work, some drivers will step on the accelerator pedal to the maximum regardless of the working condition of the dump truck, so that the dump truck runs at the maximum speed, which seriously affects the service life of the dump truck and even endangers the life safety of the driver. Summary of the invention

[0003] In view of the energy loss problem during the operation of electric drive dump trucks, the present invention provides an adaptive minimum energy consumption control method for electric drive dump trucks. By adding an accelerator pedal angle sensor and a brake pedal angle sensor, the relationship between the pedal input angle and the force generated by the pedal is obtained in time, and the minimum energy consumption control method under constraint conditions is adopted. The dump truck can be operated in a minimum energy consumption state regardless of the working condition, thereby increasing the service life of the dump truck and improving the driving experience of the dump truck.

[0004] The technical solution adopted by the present invention is:

[0005] The invention discloses a method for controlling an electric drive dump truck under working conditions with self-adaptive minimum energy consumption. Firstly, a relationship model is established according to the throttle pedal angle and the brake pedal angle and the corresponding traction force and braking force; then, the optimum traction force of the throttle pedal and the optimum braking force of the brake pedal in the minimum energy consumption state are obtained by adding a minimum energy consumption function with constraint conditions; finally, the optimum throttle pedal input angle and the brake pedal input angle are obtained by reverse calculation according to the optimum traction force of the throttle pedal and the optimum braking force of the brake pedal, and the input value when the throttle pedal and the brake pedal have the maximum angle is adjusted by a vehicle controller to be the optimum input angle of the throttle pedal and the brake pedal.

[0006] Furthermore, the relationship model between the accelerator pedal angle and the brake pedal angle and the corresponding traction and braking force includes an accelerator pedal standard model, an accelerator pedal inverse model, a brake pedal standard model, and a brake pedal inverse model.

[0007] Furthermore, in uphill working conditions, only the accelerator pedal is used to control the dump truck to complete the uphill operation, and the motor speed and vehicle load data are combined to establish a standard accelerator pedal model and an inverse accelerator pedal model of the accelerator pedal input angle and the traction force generated; in flat road working conditions, there is no test function; in downhill working conditions, only the brake pedal is used to control the dump truck to complete the downhill operation, and the motor speed and vehicle load data are combined to establish a standard brake pedal model and an inverse brake pedal model of the brake pedal input angle and the braking force generated.

[0008] Furthermore, the standard model of the accelerator pedal is ;

[0009] The inverse model of the accelerator pedal is ;

[0010] The standard model of the brake pedal is ;

[0011] The brake pedal inverse model is .

[0012] Furthermore, the minimum energy consumption function is .

[0013] Furthermore, the constraint condition is

[0014] .

[0015] Furthermore, the minimum energy consumption function with added constraints uses the minimum value principle method to obtain the optimal traction force of the accelerator pedal and the optimal braking force of the brake pedal in the minimum energy consumption state.

[0016] Furthermore, the minimum energy consumption function with added constraints is solved using the minimum value principle method:

[0017] Set the Hamiltonian function to:

[0018]

[0019] The optimal speed of the dump truck is and the optimal accompanying variable Satisfies the following canonical equation

[0020]

[0021]

[0022] Optimal control of dump trucks , Satisfy

[0023]

[0024] and , ;

[0025] Thus, the optimal traction force of the accelerator pedal in the state of minimum energy consumption is obtained. and optimal braking force of the brake pedal .

[0026] Furthermore, the optimal traction force of the accelerator pedal and the optimal braking force of the brake pedal in the minimum energy consumption state are inversely calculated using an accelerator pedal inverse model and a brake pedal inverse model to obtain the optimal accelerator pedal input angle and the brake pedal input angle.

[0027] Furthermore, a system applying the above control method includes a vehicle controller, a pressure sensor, an inclination sensor, a speed sensor, and a pedal angle sensor; the vehicle controller has data collection, analysis, storage and system control functions, the pressure sensor is used to detect the vehicle load, the inclination sensor is used to detect the angle of the vehicle's driving surface, the speed sensor is used to detect the speed of the vehicle's motor, and the pedal angle sensor is used to detect the angles of the accelerator pedal and the brake pedal.

[0028] Beneficial effects of the present invention

[0029] 1. Ramp angle It reflects the working conditions of the dump truck, such as uphill, flat road, downhill, etc. Through the minimum energy consumption function with constraints, it can be found that the method of the present invention enables the electric drive dump truck to maintain the minimum energy consumption state under all working conditions.

[0030] 2. Under the condition of minimum energy consumption, the dump truck can maintain a relatively stable operation state, and its operation mode is completely unaffected by the road conditions.

[0031] 3. When encountering an obstacle, the inventive method will equate the obstacle to an uphill, flat road, and downhill working condition, thereby maintaining the minimum energy consumption state to cross the obstacle. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is the sensor data acquisition principle diagram of the present invention;

[0033] Figure 2 It is the matching model of pedal angle and input force of the present invention;

[0034] Figure 3 It is a structural diagram of the minimum energy consumption control method of the present invention.

[0035] Note: 2% is the allowable slope measurement error. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with the accompanying drawings.

[0037] like Figure 1 The sensor data acquisition process of the method of the present invention is shown. With the vehicle controller as the core, data is collected through pressure sensors, inclination sensors, speed sensors, and pedal angle sensors to ensure the implementation of the minimum energy consumption control method. The vehicle controller has functions such as data collection, analysis, storage, and system control. The pressure sensor is used to detect the vehicle load, the inclination sensor is used to detect the angle of the vehicle's driving road surface, the speed sensor is used to detect the speed of the vehicle's motor, and the pedal angle sensor is used to detect the angle of the accelerator pedal and the brake pedal.

[0038] The invention discloses a method for controlling an electric drive dump truck under working conditions with self-adaptive minimum energy consumption. The method adds accelerator and brake pedal angle sensors to timely obtain the input angles of the accelerator and brake pedals, and calculates the corresponding relationship between the pedal input angle and the generated force according to the vehicle speed and the slope angle. The method considers the constraints of the maximum speed, maximum acceleration, maximum throttle traction and maximum braking force of the dump truck from the starting point to the end point, designs a minimum energy consumption function with constraints, and uses the minimum principle method to add the Hamiltonian function of the accompanying variable with constraints to solve and obtain the optimal traction and braking force of the dump truck when the energy consumption is minimum. The method also reversely calculates the optimal input angles of the accelerator and brake pedals, and finally the vehicle controller timely changes the maximum input state of the accelerator and brake pedals, so that the maximum input angles of the accelerator and brake pedals can maintain the optimal input angle state for operation.

[0039] The relationship model between pedal angle and pedal force

[0040] The pedal angle sensor includes the accelerator pedal angle sensor and the brake pedal angle sensor. The maximum input angle of the pedal can be changed through the vehicle controller. Figure 2 As shown, the vehicle controller calculates the relationship model between the accelerator pedal angle and the brake pedal angle and the traction and braking force generated by them, and saves it in the vehicle control system. The relationship model is divided into the accelerator pedal standard model, the accelerator pedal inverse model, the brake pedal standard model, and the brake pedal inverse model; the accelerator pedal standard model and the brake pedal standard model are collectively referred to as the pedal model, and the accelerator pedal inverse model and the brake pedal inverse model are collectively referred to as the pedal inverse model.

[0041] According to the inclination sensor data, the actual operating conditions of the dump truck are divided into three conditions: uphill, flat road, and downhill. In the uphill condition, only the accelerator pedal is used to control the dump truck to complete the uphill operation, and the motor speed and vehicle load data are combined to establish the accelerator pedal input angle and the traction force generated by the accelerator pedal standard model and the accelerator pedal inverse model; in the flat road condition, there is no test function; in the downhill condition, only the brake pedal is used to control the dump truck to complete the downhill operation, and the motor speed and vehicle load data are combined to establish the brake pedal input angle and the brake force generated by the brake pedal standard model and the brake pedal inverse model.

[0042] Analysis of adaptive driving resistance of electric drive dump truck under working conditions

[0043] In the process of driving, in order to make the dump truck move forward, backward or stop, the traction and resistance it receives must at least reach a force balance state. In different working conditions, such as uphill, flat road, and downhill, the driving resistance the dump truck receives is in different directions. The working purpose of the dump truck is to transport the goods from the starting point to the end point. Therefore, in different working conditions, the driving resistance the mining truck receives at the operating location is different. for:

[0044] (1)

[0045] In the formula,

[0046] ——The angle between the forward direction of the dump truck and the horizontal direction, for The tangent value of For an uphill slope, For a flat road, is a downhill slope, unit: degree / °;

[0047] ——The mass of the dump truck, including the dump truck’s own weight and the current actual load, ignoring the weight of the driver and the weight of the fuel consumed during the driving of the dump truck, unit: kg;

[0048] ——The rolling resistance coefficient of the current slope;

[0049] ——Gravity acceleration, m / s 2 ;

[0050] ——air resistance coefficient;

[0051] ——Air density coefficient, related to the environment of the dump truck, kg / m 3 ;

[0052] ——The windward area of ​​the dump truck during driving, m 2 ;

[0053] ——Actual speed of dump truck, m / s;

[0054] ——ramp switching function, and , only the wind resistance is considered on flat roads, and wind disturbance is ignored in both uphill and downhill conditions;

[0055] - Sign function, which ensures that the direction of the resistance on the vehicle is always opposite to the direction of the vehicle's forward movement, and .

[0056] Accelerator pedal model analysis

[0057] like Figure 2 As shown in the figure, during the uphill process, the slope angle during the uphill process is obtained through the inclination sensor only when the accelerator pedal is applied. , the accelerator pedal angle sensor collects the accelerator pedal angle The actual uphill speed v of the dump truck under the action of the accelerator pedal is calculated using the motor speed sensor data, as shown in formula (2).

[0058] (2)

[0059] In the formula,

[0060] v——actual speed of dump truck, m / s;

[0061] n——traction motor speed, r / min;

[0062] i——gear reduction ratio of dump wheel side;

[0063] R——rolling radius of dump truck tire, m;

[0064] π——pi.

[0065] Then the acceleration a of the dump truck is calculated. During the uphill process, the accelerator pedal plays a major role. Combined with Newton's second law, the traction force generated by the accelerator pedal in the uphill condition can be obtained as:

[0066] (3)

[0067] Therefore, it can be obtained at different slope angles During the uphill process, the angle of the accelerator pedal and the traction generated by the accelerator pedal The model, that is, the standard model of the accelerator pedal, is shown below

[0068] (4)

[0069] The inverse function of formula (4) can be used to obtain the accelerator pedal input angle: And the traction force generated by the corresponding accelerator pedal The inverse model of the accelerator pedal is shown below:

[0070] (5)

[0071] Note: The analysis process of the accelerator pedal model is that the dump truck passes through the ramp at a certain speed, and under the input of the accelerator pedal only, the dump truck does not slide down the slope due to its own weight.

[0072] Brake Pedal Model Analysis

[0073] At the same angle Downhill slope, the sensor collects the brake pedal angle when the mine truck is going downhill. , the actual speed v of the mining truck going downhill is calculated by the motor speed sensor, and then the acceleration a of the vehicle going downhill is calculated. In the process of going downhill, the brake pedal plays a major role. Combined with Newton's second law, the braking force generated by the brake pedal in the downhill condition can be obtained as:

[0074] (6)

[0075] Therefore, the braking force generated by the brake pedal during the downhill process at different slope angles can be obtained. and brake pedal input angle The model of the brake pedal is shown below:

[0076] (7)

[0077] The inverse function of formula (7) can be obtained as follows: and the braking force generated by the corresponding brake pedal The inverse model of the brake pedal is shown below:

[0078] (8)

[0079] Note: The analysis process of the brake pedal model is that the dump truck reaches the bottom of the slope safely at a certain speed, and when only the brake pedal is input, the dump truck does not slide down the slope due to its own weight.

[0080] Working condition adaptive minimum energy consumption control algorithm

[0081] The operation of the accelerator pedal and brake pedal of a dump truck is an important means to reduce the energy consumption of the dump truck drive system. The purpose of this patent is to find the optimal dump truck operation strategy so that the dump truck consumes the least energy during the cargo transportation process. The minimum energy consumption algorithm structure is shown in the figure below: Figure 3 shown.

[0082] Design of minimum energy consumption control algorithm

[0083] Assume that the speed of the dump truck at the start and end is 0, and the start time is set to The time of arrival at the transportation location is , then the energy consumed by the dump truck from the starting point to the end point during transportation is the minimum energy consumption function:

[0084] (9)

[0085] in, is the total traction energy consumption of the dump truck during transportation, is the total traction force on the dump truck, is the current speed of the dump truck.

[0086] According to the actual working conditions of dump trucks, considering the constraints shown in formula (10),

[0087] (10)

[0088] In the formula,

[0089] ——The distance the dump truck has traveled at time t, m;

[0090] ——the speed of the dump truck at time t, m / s;

[0091] ——Acceleration of the dump truck at time t, m / s 2 ;

[0092] ——The total distance traveled by the dump truck from the starting point to the end point, m;

[0093] ——The maximum speed of the dump truck during its travel, m / s;

[0094] ——The traction force generated by the accelerator pedal at time t, N;

[0095] ——The maximum traction force generated by the accelerator pedal when the vehicle speed is the minimum during the uphill process, N;

[0096] ——The braking force generated by the brake pedal at time t, N.

[0097] ——The maximum braking force generated by the brake pedal when the vehicle speed is the minimum during the downhill process, N.

[0098] Note: A force greater than 0 indicates that the direction of the force is the same as the direction of travel of the dump truck, and a force less than 0 indicates that the direction of the force is opposite to the direction of travel of the dump truck.

[0099] Minimum Principle Method

[0100] Formula (9) cannot be directly obtained due to the constraints of formula (10). Therefore, for the minimum energy consumption function formula (9) with the constraint formula (10), the following minimum principle method can be used to obtain the optimal traction force of the accelerator pedal: , optimal braking force of the brake pedal , and make formula (9) obtain the minimum value, the process is:

[0101] Set the Hamiltonian function to:

[0102] (11)

[0103] in, It is an accompanying variable parameter to prevent the dump truck from being damaged due to excessive or insufficient acceleration.

[0104] The optimal speed of the dump truck is and the optimal accompanying variable It satisfies the following canonical equation,

[0105] (12)

[0106] (13)

[0107] Optimal control of dump trucks , Satisfy respectively,

[0108] (14)

[0109] (15)

[0110] and , .

[0111] The optimal traction force generated by the accelerator pedal can be obtained by equations (14) and (15): and the best braking force generated by the brake pedal , and make the energy consumed by the dump truck from the starting point to the end point (9) take the minimum value.

[0112] Pedal maximum angle design

[0113] Obtaining the best traction force through the minimum principle and braking force , so that the energy consumed by the dump truck during transportation is minimized, and then the optimal input angles of the accelerator pedal and the brake pedal can be obtained by using the accelerator pedal inverse model (5) and the brake pedal inverse model (8). In order to facilitate the driver's operation, the input values ​​of the accelerator pedal and the brake pedal at the maximum angle are changed through the vehicle controller, so that the accelerator pedal input at the maximum angle is the input angle of the optimal traction force, and the brake pedal input at the maximum angle is the input angle of the optimal braking force.

[0114] The method of the present invention uses the minimum energy consumption function to achieve the minimum energy consumption under different working conditions, improves the driving ability of the dump truck, and can effectively reduce the energy consumed by the dump truck when transporting goods under different working conditions. For the minimum energy consumption function with constraints, the present invention only uses the minimum value principle method to solve and obtain the optimal control force. It should be understood that the embodiments of the present application and the specific features in the embodiments are detailed descriptions of the technical solutions of the present application, rather than limitations on the technical solutions of the present application. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments can be combined with each other, and other data characteristics are also designed in the same way.

Claims

1. A method for controlling the minimum energy consumption of an electric drive dump truck under working conditions, characterized in that: Firstly, a relationship model is established according to the throttle pedal angle and the brake pedal angle and their corresponding traction and braking force; then, the optimal traction of the throttle pedal and the optimal braking force of the brake pedal under the minimum energy consumption state are obtained by adding the minimum energy consumption function with constraints; finally, the optimal throttle pedal input angle and the brake pedal input angle are obtained by reverse calculation according to the optimal traction of the throttle pedal and the optimal braking force of the brake pedal, and the input value at the maximum angle of the throttle pedal and the brake pedal is adjusted by the vehicle controller to be the optimal input angle of the throttle pedal and the brake pedal.

2. The method for controlling the working condition of an electric drive dump truck according to claim 1, characterized in that: The relationship models between the accelerator pedal angle and the brake pedal angle and the corresponding traction and braking force include an accelerator pedal standard model, an accelerator pedal inverse model, a brake pedal standard model, and a brake pedal inverse model.

3. The method for controlling the working condition of an electric drive dump truck according to claim 2, characterized in that: In uphill working conditions, only the accelerator pedal is used to control the dump truck to complete the uphill operation, and the motor speed and vehicle load data are combined to establish the accelerator pedal input angle and the traction force generated by the accelerator pedal standard model and the accelerator pedal inverse model; in flat road working conditions, there is no test function; in downhill working conditions, only the brake pedal is used to control the dump truck to complete the downhill operation, and the motor speed and vehicle load data are combined to establish the brake pedal input angle and the brake force generated by the brake pedal standard model and the brake pedal inverse model.

4. The method for controlling the operating condition of an electric drive dump truck according to claim 2, characterized in that: The standard model of the accelerator pedal is ; The inverse model of the accelerator pedal is ; The standard model of the brake pedal is ; The brake pedal inverse model is .

5. The method for controlling the operating condition of an electric drive dump truck according to claim 1, characterized in that: The minimum energy consumption function is: 。 6. The method for controlling the operating condition of an electric drive dump truck according to claim 1, characterized in that: The constraints are 。 7. The method for controlling the operating condition of an electric drive dump truck according to claim 1, characterized in that: The minimum energy consumption function with added constraints uses the minimum value principle method to obtain the optimal traction force of the accelerator pedal and the optimal braking force of the brake pedal in the minimum energy consumption state.

8. The method for controlling the working condition of an electric drive dump truck according to claim 7, characterized in that: The minimum energy consumption function with added constraints is solved by the minimum value principle method: Set the Hamiltonian function to: ， The optimal speed of the dump truck is and the optimal accompanying variable Satisfies the following canonical equation ， ； Optimal control of dump trucks , Satisfy ， and , ; Thus, the optimal traction force of the accelerator pedal in the state of minimum energy consumption is obtained. and optimal braking force of the brake pedal .

9. The method for controlling the operating condition of an electric drive dump truck according to claim 1, characterized in that: The optimal traction force of the accelerator pedal and the optimal braking force of the brake pedal in the minimum energy consumption state are inversely calculated using an accelerator pedal inverse model and a brake pedal inverse model to obtain the optimal accelerator pedal input angle and the brake pedal input angle.

10. A system using the control method according to claim 1, characterized in that: It includes a vehicle controller, a pressure sensor, an inclination sensor, a speed sensor, and a pedal angle sensor; the vehicle controller has data collection, analysis, storage and system control functions, the pressure sensor is used to detect the vehicle load, the inclination sensor is used to detect the angle of the vehicle's driving surface, the speed sensor is used to detect the speed of the vehicle's motor, and the pedal angle sensor is used to detect the angles of the accelerator pedal and the brake pedal.

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