A speed planning method for improving fuel efficiency of unmanned mining vehicles

Abstract

The present invention relates to a speed planning method for improving the fuel efficiency of unmanned mining vehicles, belonging to the technical field of planning and control for unmanned mining vehicles. The speed planning method of the present invention combines actual operating scenarios with information about the actual operating status of the vehicle and the surrounding environment to generate a smooth speed trajectory that satisfies the vehicle's kinematics. This method solves the instability of existing methods that only improve fuel efficiency within the vehicle itself. By implementing real-time dynamic control, it achieves a better improvement in fuel efficiency for mining trucks.

Description

Technical Field

[0001] The present invention belongs to the technical field of planning and control of unmanned mining vehicles, and in particular relates to a vehicle speed planning method for improving the fuel utilization rate of unmanned mining vehicles. Background Art

[0002] Unmanned driving technology in open-pit mines plays a crucial role in contemporary equipment manufacturing and is a key development target for the future Industrial Internet. Compared to traditional manual driving, unmanned driving in open-pit mines not only effectively ensures the safety of workers and property, effectively reduces driver labor costs, but also improves vehicle utilization and operational efficiency. For mining vehicles, reducing unmanned operating costs has two key aspects: first, it reduces the labor costs associated with hiring drivers, and second, it also focuses on the fuel efficiency of unmanned mining trucks.

[0003] Currently, a common approach to improving the fuel economy of mining trucks is to add an automatic engine start-stop function. However, this method can cause the engine to not start and stop properly due to low temperatures in mining areas. Another approach involves optimizing the vehicle's powertrain output, including adjusting engine speed and transmission gears. While this can improve fuel economy to a certain extent, it cannot meet the requirements of comprehensive operating conditions. Summary of the Invention

[0004] In view of the above analysis, an embodiment of the present invention aims to provide a vehicle speed planning method for improving the fuel utilization rate of unmanned mining vehicles. By combining the actual operation scene and the actual operating status of the vehicle and the surrounding environment information, a smooth speed trajectory that satisfies the vehicle kinematics is generated, which solves the instability problem of the existing method of only improving the economic fuel efficiency of the vehicle itself. Through real-time dynamic regulation, a better improvement in the economic fuel utilization rate of mining trucks is achieved.

[0005] A speed planning method for improving the fuel efficiency of an unmanned mining vehicle according to the present invention comprises the following steps:

[0006] Step 1: Obtain road information and vehicle status information for the current operation scenario;

[0007] Step 2: Based on the road information and vehicle status information of the current operation scenario obtained in Step 1, as well as the vehicle's own dynamic characteristics, vehicle constraints and vehicle acceleration constraints are established; based on the vehicle constraints and vehicle acceleration constraints, the optimal expected vehicle speed is obtained;

[0008] Step 3: Set the sampling length of the planned road;

[0009] Step 4: Based on the optimal expected vehicle speed and planned road sampling length obtained in steps 2 and 3, plan the automatic driving speed curve of the unmanned vehicle in the mining area;

[0010] Step 5: Obtain the speed control command required by the vehicle based on the generated autonomous driving speed curve and the mining area where the vehicle is currently located; and send the speed control command to the driving system of the unmanned vehicle in the mining area.

[0011] Optionally, the dynamic characteristics of the vehicle itself are the vehicle's maximum speed, minimum acceleration, maximum acceleration, minimum acceleration change rate, and maximum acceleration change rate.

[0012] Optionally, the expression of the constructed vehicle constraint condition is:

[0013]

[0014] Among them, v i is the actual speed of the vehicle at the i-th path point; v max is the maximum speed of the vehicle; v i+1 is the actual speed of the vehicle at the i+1th path point; △s is the distance between two adjacent path points; a i is the acceleration of the vehicle at the i-th path point; is the acceleration corresponding to the slope of the vehicle at the i-th path point; Output acceleration of the vehicle at the i+1th path point; is the vehicle output acceleration at the i-th path point; a i+1 is the vehicle acceleration at the i+1th path point; is the acceleration corresponding to the slope of the vehicle at the i+1th path point; Output the minimum acceleration of the vehicle at the i-th path point; Output the maximum acceleration of the vehicle at the i-th path point; The minimum acceleration rate of the vehicle output at the i-th path point; j i is the acceleration change rate of the vehicle at the i-th path point; Output the maximum acceleration rate of the vehicle at the i-th path point.

[0015] Optionally, the expression of the vehicle acceleration constraint condition is constructed as:

[0016] a v,min v v,max

[0017]

[0018] Among them, a​​v represents the vehicle's own acceleration; a v，min Represents the vehicle's own minimum acceleration; a v，max Represents its maximum speed; a des，min Represents the minimum expected acceleration of the vehicle; a des，max Represents the maximum expected acceleration of the vehicle.

[0019] Optionally, based on the vehicle constraints and the vehicle acceleration constraints, the optimal expected vehicle speed a0 is solved, and the expression is:

[0020]

[0021] Where L is the objective function; w1, w2 and w3 are weights; n is the total number of path points, i = 1, 2, ..., n; V i ref is the expected speed of the vehicle at the i-th path point.

[0022] Optionally, in step 5, the throttle opening and brake pedal opening commands required by the vehicle are obtained through the vehicle speed control command; and the throttle opening and brake pedal opening commands are sent to the driving system of the unmanned vehicle in the mining area.

[0023] Compared with the prior art, the present invention has at least the following beneficial effects:

[0024] The method of the present invention implements low-fuel-consumption speed planning for autonomous driving by controlling the road environment and the desired speed and / or acceleration of unmanned mining vehicles. This effectively avoids the ignition anomalies and insignificant improvements that can occur when only focusing on vehicle fuel efficiency in the harsh mining environment. It provides real-time fuel efficiency improvements for various operational scenarios. It also improves vehicle stability and reduces the risk of vehicle failures caused by large and frequent throttle and brake fluctuations. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings are only for purposes of illustrating particular embodiments and are not to be considered limiting of the invention.

[0026] Figure 1 Flowchart of the vehicle speed planning method of the present invention. DETAILED DESCRIPTION

[0027] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] A specific embodiment of the present invention, as Figure 1 , discloses a speed planning method for improving the fuel utilization rate of an unmanned mining vehicle, comprising the following steps:

[0029] Step 1: Obtain road information and vehicle status information for the current operation scenario;

[0030] Optionally, the road information is the road slope and road curvature. A one-dimensional lookup table is established by obtaining the road curvature and the maximum speed limit for curved roads in the mining area at the mining site. The maximum speed of the vehicle is limited by the queried speed, and there will be different requirements based on different mining areas; the vehicle status information is the location of the vehicle.

[0031] Step 2: Based on the road information and vehicle status information of the current operation scenario obtained in Step 1, as well as the vehicle's own dynamic characteristics, vehicle constraints and vehicle acceleration constraints are established; based on the vehicle constraints and vehicle acceleration constraints, the optimal expected vehicle speed is obtained;

[0032] Optionally, the dynamic characteristics of the vehicle itself are the vehicle's maximum speed, minimum acceleration, maximum acceleration, minimum acceleration change rate, and maximum acceleration change rate.

[0033] The expression of vehicle constraints is:

[0034]

[0035] Among them, v i is the actual speed of the vehicle at the i-th path point; v max is the maximum speed of the vehicle; v i+1 is the actual speed of the vehicle at the i+1th path point; △s is the distance between two adjacent path points; a i is the acceleration of the vehicle at the i-th path point; is the acceleration corresponding to the slope of the vehicle at the i-th path point; Output acceleration of the vehicle at the i+1th path point; is the vehicle output acceleration at the i-th path point; a i+1 is the vehicle acceleration at the i+1th path point; is the acceleration corresponding to the slope of the vehicle at the i+1th path point; Output the minimum acceleration of the vehicle at the i-th path point; Output the maximum acceleration of the vehicle at the i-th path point; The minimum acceleration rate of the vehicle output at the i-th path point; j i is the acceleration change rate of the vehicle at the i-th path point; Output the maximum acceleration rate of the vehicle at the i-th path point.

[0036] The expression of vehicle acceleration constraint is:

[0037] av,min v v,max

[0038]

[0039] Among them, a v represents the vehicle's own acceleration; a v，min Represents the vehicle's own minimum acceleration; a v，max Represents its maximum speed; a des，min Represents the minimum expected acceleration of the vehicle; a des，max Represents the maximum expected acceleration of the vehicle.

[0040] It can be understood that a waypoint is a point on a road that a vehicle passes through.

[0041] Based on the vehicle constraints and vehicle acceleration constraints, the optimal expected vehicle speed a0 is solved, and the expression is:

[0042]

[0043] Where L is the objective function; w1, w2 and w3 are weights; n is the total number of path points, i = 1, 2, ..., n; V i ref is the expected speed of the vehicle at the i-th path point.

[0044] Step 3: Set the sampling length of the planned road;

[0045] Step 4: Based on the optimal expected vehicle speed and planned road sampling length obtained in steps 2 and 3, plan the automatic driving speed curve of the unmanned vehicle in the mining area;

[0046] The expression of the automatic driving speed curve is:

[0047] Δv=a0*Δt;

[0048] Among them, Δv is the desired vehicle speed finally obtained, and Δt is the set cycle time;

[0049] Step 5: Based on the generated autonomous driving speed curve and the mining area where the vehicle is currently located, the throttle opening and brake pedal opening commands required for the vehicle are calculated according to the expected vehicle speed; and the commands are sent to the driving system of the unmanned vehicle in the mining area.

[0050] Optionally, the mining area where the vehicle is currently located includes a normal road driving area, a loading area, and an unloading area.

[0051] Optionally, the vehicle drives according to the instructions, which can improve fuel efficiency while driving.

[0052] ​​The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A speed planning method for improving the fuel efficiency of unmanned mining vehicles, characterized in that: The following steps are involved: Step 1: Obtain road information and vehicle status information for the current operation scenario; Step 2: Based on the road information and vehicle status information of the current operation scenario obtained in Step 1, as well as the vehicle's own dynamic characteristics, vehicle constraints and vehicle acceleration constraints are established; based on the vehicle constraints and vehicle acceleration constraints, the optimal expected vehicle speed is obtained; The expression of the constructed vehicle constraint condition is: Among them, v i is the actual speed of the vehicle at the i-th path point; v max is the maximum speed of the vehicle; v i+1 is the actual speed of the vehicle at the i+1th path point; △s is the distance between two adjacent path points; a i is the acceleration of the vehicle at the i-th path point; is the acceleration corresponding to the slope of the vehicle at the i-th path point; Output acceleration of the vehicle at the i+1th path point; is the vehicle output acceleration at the i-th path point; a i+1 is the vehicle acceleration at the i+1th path point; is the acceleration corresponding to the slope of the vehicle at the i+1th path point; Output the minimum acceleration of the vehicle at the i-th path point; Output the maximum acceleration of the vehicle at the i-th path point; The minimum acceleration rate of the vehicle output at the i-th path point; j i is the acceleration change rate of the vehicle at the i-th path point; Output the maximum acceleration rate of the vehicle at the i-th path point; The expression of the constructed vehicle acceleration constraint is: a v,min <a v <a v,max Among them, a v represents the vehicle's own acceleration; a v，min Represents the vehicle's own minimum acceleration; a v，max Represents its maximum speed; a des，min Represents the minimum expected acceleration of the vehicle; a des，max Represents the maximum expected acceleration of the vehicle; Based on the vehicle constraints and vehicle acceleration constraints, the expression for the optimal expected vehicle speed a0 is: Where L is the objective function; w1, w2 and w3 are weights; n is the total number of path points, i = 1, 2, ..., n; V i ref is the expected speed of the vehicle at the i-th path point; Step 3: Set the sampling length of the planned road; Step 4: Based on the optimal expected vehicle speed and planned road sampling length obtained in steps 2 and 3, plan the automatic driving speed curve of the unmanned vehicle in the mining area; Step 5: Obtain the speed control command required by the vehicle based on the generated autonomous driving speed curve and the mining area where the vehicle is currently located; and send the speed control command to the driving system of the unmanned vehicle in the mining area.

2. The vehicle speed planning method according to claim 1, characterized in that: The vehicle's own dynamic characteristics are the vehicle's maximum speed, minimum acceleration, maximum acceleration, minimum acceleration change rate, and maximum acceleration change rate.

3. The vehicle speed planning method according to claim 1, characterized in that: In step 5, the throttle opening and brake pedal opening commands required by the vehicle are obtained through the vehicle speed control command; the throttle opening and brake pedal opening commands are sent to the driving system of the unmanned vehicle in the mining area.

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