Oil-saving PCC vehicle speed control method based on linear following algorithm

Abstract

The invention relates to the technical field of commercial vehicle intelligent driving, and particularly discloses an oil-saving PCC vehicle speed control method based on a linear following algorithm, and the method mainly comprises four parts: an ECM controller, a CAN bus, a VCU controller, and a linear control program package. The method comprises the following steps of: dynamically planning an optimal vehicle speed and controlling an implementation process of the optimal vehicle speed as a core of a system, arranging a linear control program package in a VCU controller, receiving a vehicle speed planning instruction of an ECM controller through a CAN bus, dividing an execution process into a plurality of execution cycles by adopting a linear following algorithm, calculating a vehicle speed of each execution cycle, and controlling the implementation process of the optimal vehicle speed according to the vehicle speed planning instruction. The vehicle is controlled through the VCU controller, the smooth speed increasing and reducing process from the current vehicle speed to the optimal planned vehicle speed is achieved, the vehicle speed is stably controlled, and better fuel economy is obtained while the driving comfort is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent driving for commercial vehicles, and particularly to a fuel-saving PCC vehicle speed control method based on a linear following algorithm. Background Technique

[0002] The PCC (Predictive Cruise) vehicle speed control system is an advanced cruise control system that coordinates the control of the engine and transmission according to the road information ahead, and finally controls the speed change, which can effectively relieve driving fatigue and save fuel.

[0003] The traditional PCC (Predictive Cruise) vehicle speed control system for commercial vehicles outputs the planned PCC vehicle speed, and the whole vehicle dynamically adjusts through torque control and directly executes the planned vehicle speed. When the change in adjacent planned vehicle speeds is large, the whole vehicle will quickly adjust the torque to make the vehicle speed reach the planned vehicle speed, resulting in a large instantaneous torque oscillation, weakening the optimization effect of fuel economy, and also bringing poor ride comfort to users.

[0004] Therefore, it is necessary to design a fuel-saving PCC vehicle speed control method based on a linear following algorithm, which decomposes the process of achieving the planned vehicle speed into several cycles for execution, calculates the process vehicle speed to reach the planned vehicle speed using the linear following algorithm, and gives the vehicle speed command for each execution cycle, so as to solve the problems of poor fuel economy of the planned vehicle speed and poor ride comfort caused by torque oscillation in the existing traditional commercial vehicle PCC vehicle speed control system. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a fuel-saving PCC vehicle speed control method based on a linear following algorithm.

[0006] The technical solution adopted by the present invention to solve its technical problems is: a fuel-saving PCC vehicle speed control method based on a linear following algorithm, including the following steps:

[0007] S1. The ECM controller generates input signals: The ECM controller generates a predictive cruise control activation signal, an optimal planned vehicle speed, and a planned gear as the input signals of the system;

[0008] S2. The CAN bus transmits the input signals: The vehicle CAN bus transmits the input signals in the previous step to the VCU controller;

[0009] S3. Calculate the linear following vehicle speed sequence: In order to achieve a smooth transition between the current execution vehicle speed and the optimal planned vehicle speed, the linear control program package decomposes the execution process into several stages and calculates the planned vehicle speed for each stage, so as to obtain a set of linear following vehicle speed sequences within the current planned mileage;

[0010] S4. The VCU controller executes the vehicle speed sequence: The VCU controller periodically executes the vehicle speed sequence generated in step S3.

[0011] Preferably, the ECM controller in step S1 generates an input signal for the system based on map information and the current vehicle state information.

[0012] Preferably, the program package for calculating the linear following vehicle speed sequence in step S3 is set in the VCU controller, and specifically includes the following steps:

[0013] S31. Obtain the optimal planned vehicle speed: The CAN bus transmits the ECM controller signal to the VCU controller;

[0014] S32. Calculate the vehicle speed growth rate K v : Calculate the vehicle speed growth rate K based on the received optimal planned vehicle speed v , and the formula is:

[0015]

[0016]

[0017] S33. Calculate the vehicle speed for the execution cycle: Linearly calculate the vehicle speed according to the execution cycle of the VCU controller:

[0018] V t = V1 + tK v (3);

[0019] S34. Iterative calculation: If the current running mileage is less than the planned mileage, update the current execution vehicle speed V1, and the formula is:

[0020] V1 = V t (4);

[0021] S35. Repeat S33 until the current running mileage reaches the planned mileage.

[0022] Preferably, in formula 1 and formula 2 in step S32, ds is the planned mileage, is the predicted average vehicle speed of the current mileage, V1 is the current execution vehicle speed, and V 优 is the optimal planned vehicle speed.

[0023] Preferably, in formula 3 in step S33, V1 is the current execution vehicle speed, V t is the vehicle speed for the execution cycle t, t is the execution cycle of the VCU controller, and K v is the vehicle speed growth rate.

[0024] Preferably, in formula 4 in step S34, V1 is the execution vehicle speed of the previous cycle, and V tis the vehicle speed at the current execution cycle t.

[0025] The present invention has the following beneficial effects:

[0026] The fuel-saving PCC vehicle speed control method based on the linear following algorithm designed by the present invention decomposes the realization process of the planned vehicle speed into several cycles of execution. It uses the linear following algorithm to calculate the process vehicle speed to reach the planned vehicle speed, gives the vehicle speed command for each execution cycle, and through the step-by-step execution process of the vehicle speed, enables the vehicle to gradually adjust to the planned vehicle speed, avoiding the occurrence of sudden acceleration / sudden deceleration, reducing the intense oscillation of torque, thereby improving the ride comfort and obtaining better fuel economy.

[0027] The fuel-saving PCC vehicle speed control method based on the linear following algorithm designed by the present invention realizes the smooth transition between the current execution vehicle speed and the optimal planned vehicle speed by calculating and decomposing the execution process of the optimal planned vehicle speed, avoids the severe torque fluctuations often occurring in the traditional PCC control system, and further optimizes the fuel-saving effect of the whole vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is the flowchart of the fuel-saving PCC vehicle speed control method based on the linear following algorithm. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The following will further clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] Embodiment 1:

[0031] As Figure 1 shown, a fuel-saving PCC vehicle speed control system based on the linear following algorithm mainly includes 4 parts: ECM controller, CAN bus, VCU controller, and linear control program package. The system predicts the road conditions based on map information, vehicle position, and the road conditions ahead, dynamically plans the optimal vehicle speed, and controls the realization process of the optimal vehicle speed. As the core of the system, the linear control program package is built into the VCU controller. Through the CAN bus, it receives the vehicle speed planning command from the ECM, divides the execution process into several execution cycles using the linear following algorithm, calculates and gives the vehicle speed for each execution cycle, and realizes vehicle control through the VCU controller, realizing a smooth acceleration and deceleration process from the current vehicle speed to the optimal planned vehicle speed, and stably controlling the vehicle speed, obtaining better fuel economy while improving the ride comfort.

[0032] Embodiment 2: The specific working principle implemented using the structure of Embodiment 1.

[0033] The basic principle of the present invention includes the following steps:

[0034] Step 1, the ECM controller generates input signals: The ECM controller generates a predictive cruise control activation signal, an optimal planned vehicle speed, and a planned gear as input signals of the system according to the map information and the current vehicle state information.

[0035] Step 2, the CAN bus transmits the input signals: The vehicle CAN bus transmits the input signals in the previous step to the VCU controller.

[0036] Step 3, calculate the linear following vehicle speed sequence: In order to achieve a smooth transition between the current execution vehicle speed and the optimal planned vehicle speed, the linear control program package decomposes the execution process into several stages and calculates the planned vehicle speed of each stage, so as to obtain a set of linear following vehicle speed sequences within the current planned mileage.

[0037] Specifically, it includes the following steps:

[0038] (1) Obtain the optimal planned vehicle speed: The CAN bus transmits the ECM controller signal to the VCU controller.

[0039] (2) Calculate the vehicle speed growth rate K v : Calculate the vehicle speed growth rate K according to the received optimal planned vehicle speed v , and the formula is:

[0040]

[0041]

[0042] ds in Formula 1 and Formula 2 is the planned mileage, is the predicted average vehicle speed of the current mileage, V1 is the current execution vehicle speed, and V 优 is the optimal planned vehicle speed.

[0043] (3) Calculate the vehicle speed of the execution cycle: Calculate the vehicle speed linearly according to the execution cycle of the VCU controller:

[0044] V t = V1 + tK v (3);

[0045] V1 in Formula 3 is the current execution vehicle speed, V t is the vehicle speed of the execution cycle t, t is the execution cycle of the VCU controller, and K v is the vehicle speed growth rate.

[0046] (4) Iterative calculation: If the current running mileage is less than the planned mileage, update the current execution vehicle speed V1, and the formula is:

[0047] V1 = Vt (4);

[0048] In Formula 4, V1 is the execution vehicle speed of the previous cycle, and V t is the vehicle speed of the current execution cycle t.

[0049] (5) Repeat step (3) until the current running mileage reaches the planned mileage.

[0050] Step 4: The VCU controller executes the vehicle speed sequence: The VCU controller periodically executes the vehicle speed sequence generated in step S3.

[0051] Through the calculation and decomposition of the execution process of the optimal planned vehicle speed, the present invention realizes a smooth transition between the current execution vehicle speed and the optimal planned vehicle speed, avoids the severe torque fluctuations often occurring in traditional PCC control systems, and further optimizes the fuel-saving effect of the whole vehicle. According to experimental verification, compared with free driving, the whole vehicle saves 1.67 L / 100 km under comprehensive working conditions.

[0052] Through the stepped execution process of the vehicle speed, the present invention avoids the rapid acceleration / rapid deceleration processes often occurring in traditional PCC control systems, and greatly improves the ride comfort of the whole vehicle.

[0053] The present invention is not limited to the above embodiments. Any person should know that structural changes made under the inspiration of the present invention, as long as they have the same or similar technical solutions as the present invention, all fall within the protection scope of the present invention.

[0054] The technologies, shapes, and structures not described in detail in the present invention are all well-known technologies.

Claims

1. A fuel-saving PCC vehicle speed control method based on a linear following algorithm, characterized in that, It includes the following steps: S1. The ECM controller generates input signals: The ECM controller generates a predictive cruise control activation signal, an optimal planned vehicle speed, and a planned gear as the input signals of the system; S2. The CAN bus transmits the input signals: The vehicle CAN bus transmits the input signals in the previous step to the VCU controller; S3. Calculate the linear following vehicle speed sequence: In order to achieve a smooth transition between the current execution vehicle speed and the optimal planned vehicle speed, the linear control program package decomposes the execution process into several stages and calculates the planned vehicle speed for each stage, thereby obtaining a set of linear following vehicle speed sequences within the current planned mileage; S4. The VCU controller executes the vehicle speed sequence: The VCU controller periodically executes the vehicle speed sequence generated in step S3.

2. The fuel-saving PCC vehicle speed control method based on the linear following algorithm according to claim 1, characterized in that The ECM controller in step S1 generates the input signals of the system according to the map information and the current vehicle state information.

3. The fuel-saving PCC vehicle speed control method based on the linear following algorithm according to claim 1, characterized in that, The program package for calculating the linear following vehicle speed sequence in step S3 is set in the VCU controller, and specifically includes the following steps: S31. Obtain the optimal planned vehicle speed: The CAN bus transmits the ECM controller signal to the VCU controller; S32. Calculate the vehicle speed growth rate K v : Calculate the vehicle speed growth rate K based on the received optimal planned vehicle speed v , and the formula is: S33. Calculate the vehicle speed of the execution cycle: According to the execution cycle of the VCU controller, linearly calculate the vehicle speed: V t = V1 + tK v (3); S34. Iterative calculation: If the current running mileage is less than the planned mileage, update the current execution vehicle speed V1, and the formula is: V1 = V t (4); S35. Repeat S33 until the current running mileage reaches the planned mileage.

4. The fuel-saving PCC vehicle speed control method based on the linear following algorithm according to claim 3, characterized in that, In the formula 1 and formula 2 in the step S32, ds is the planned mileage, is the predicted average speed of the current mileage, V1 is the current execution speed, V 优 is the optimal planned speed.

5. The fuel-saving PCC vehicle speed control method based on the linear following algorithm according to claim 3, wherein In the formula 3 in the step S33, V1 is the current execution vehicle speed, V t is the vehicle speed at the execution cycle t, where t is the execution cycle of the VCU controller, and K v is the vehicle speed growth rate.

6. The fuel-saving PCC vehicle speed control method based on the linear following algorithm according to claim 3, wherein In the formula 4 in step S34, V1 is the execution vehicle speed in the previous cycle, and V t is the vehicle speed in the current execution cycle t.

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