Disclosure of Invention
In order to solve the technical problems in the background art, the invention provides a vehicle speed estimation method and system based on a neural network.
In order to achieve the purpose, the invention provides the following scheme:
a neural network-based vehicle speed estimation method, the vehicle speed estimation method comprising:
obtaining a training sample; the data in the training sample is vehicle real-time data in a precondition test; the vehicle real-time data comprises four wheel speeds, steering wheel angles, yaw acceleration, longitudinal acceleration and lateral acceleration;
expanding the training input quantity in the training sample into a 8-by-8 symmetric vehicle real-time data matrix;
determining a training output quantity; the training output is the lateral speed and the longitudinal speed of the vehicle to the ground;
training a convolutional neural network according to the symmetric vehicle real-time data matrix and the training output quantity to obtain a trained convolutional neural network model;
acquiring real-time data of a current vehicle; the real-time data of the current vehicle comprise four wheel speeds of the current vehicle, a steering wheel angle of the current vehicle, a yaw acceleration of the current vehicle, a longitudinal acceleration of the current vehicle and a lateral acceleration of the current vehicle;
and inputting the real-time data of the current vehicle into the trained convolutional neural network model, and estimating the transverse speed and the longitudinal speed of the current vehicle to the ground.
Optionally, the inputting the real-time data of the current vehicle into the trained convolutional neural network model to estimate the lateral speed and the longitudinal speed of the current vehicle to the ground specifically includes:
converting the real-time data of the current vehicle according to the form of the training input quantity;
and inputting the converted real-time data of the current vehicle into the trained convolutional neural network model, and estimating the transverse speed and the longitudinal speed of the current vehicle to the ground.
Optionally, the values of the four wheel speeds, the steering wheel angles, the yaw acceleration, the longitudinal acceleration and the lateral acceleration are used as the training input quantities of the training samples in a vector form.
Optionally, the training input amount is [ wh1 wh2 wh3 wh4 str yaw log lat ]; wherein wh1 wh2 wh3 wh4 represents a first wheel speed, a second wheel speed, a third wheel speed, and a fourth wheel speed, respectively; str denotes a steering wheel angle; yaw represents Yaw acceleration; log represents a longitudinal acceleration; lat represents lateral acceleration.
Optionally, the symmetric vehicle real-time data matrix is:
【wh1 wh1 wh1 wh1 wh1 wh1 wh1 wh1】
【wh1 wh2 wh2 wh2 wh2 wh2 wh2 wh2】
【wh1 wh2 wh3 wh3 wh3 wh3 wh3 wh3】
【wh1 wh2 wh3 wh4 wh4 wh4 wh4 wh4】
【wh1 wh2 wh3 wh4 str str str str】
【wh1 wh2 wh3 wh4 str yaw yaw yaw】
【wh1 wh2 wh3 wh4 str yaw log log】
【wh1 wh2 wh3 wh4 str yaw log lat】。
optionally, the training output is the lateral speed and the longitudinal speed of the vehicle to the ground measured by the two-axis optical sensor at the same time.
Optionally, the training output is [ vlat vllog ]; where vlat represents the lateral velocity and vlog represents the longitudinal velocity.
A neural network-based vehicle speed estimation system, the vehicle speed estimation system method comprising:
the training sample acquisition module is used for acquiring a training sample; the data in the training sample is vehicle real-time data in a precondition test; the vehicle real-time data comprises four wheel speeds, steering wheel angles, yaw acceleration, longitudinal acceleration and lateral acceleration;
the symmetric vehicle real-time data matrix determining module is used for expanding the training input quantity in the training sample into an 8 × 8 symmetric vehicle real-time data matrix;
a training output quantity determining module for determining a training output quantity; the training output is the lateral speed and the longitudinal speed of the vehicle to the ground;
the convolutional neural network training module is used for training a convolutional neural network according to the symmetric vehicle real-time data matrix and the training output quantity to obtain a trained convolutional neural network model;
the current vehicle real-time data acquisition module is used for acquiring the real-time data of the current vehicle; the real-time data of the current vehicle comprise four wheel speeds of the current vehicle, a steering wheel angle of the current vehicle, a yaw acceleration of the current vehicle, a longitudinal acceleration of the current vehicle and a lateral acceleration of the current vehicle;
and the current vehicle-to-ground transverse speed and longitudinal speed estimation module is used for inputting the real-time data of the current vehicle into the trained convolutional neural network model and estimating the transverse speed and the longitudinal speed of the current vehicle to the ground.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
the invention provides a vehicle speed estimation method and system based on a neural network, which utilize a convolution neural network to output real-time longitudinal speed and transverse speed of a vehicle to the ground by taking a symmetric vehicle real-time data matrix as input through convolution calculation convergence.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention aims to provide a vehicle speed estimation method and a vehicle speed estimation system based on a neural network, which are not only suitable for the limited working condition of vehicle slip, but also have small calculated amount.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
The invention utilizes the convolutional neural network to accurately obtain the transverse speed and the longitudinal speed of the vehicle to the ground in real time.
Fig. 1 is a schematic flow chart of a vehicle speed estimation method based on a neural network according to an embodiment of the present invention, and as shown in fig. 1, the vehicle speed estimation method based on the neural network according to the embodiment of the present invention includes the following steps:
step 101: training samples are obtained.
Training data in the sample as vehicle real-time data in the precondition test; the vehicle real-time data comprises four wheel speeds, steering wheel corners, yaw acceleration, longitudinal acceleration and lateral acceleration, and the values of the four wheel speeds, the steering wheel corners, the yaw acceleration, the longitudinal acceleration and the lateral acceleration are used as training input quantities of training samples in a vector form.
The training input was [ wh1 wh2 wh3 wh4 str yaw log lat ]. Wherein wh1 wh2 wh3 wh4 represents a first wheel speed, a second wheel speed, a third wheel speed, and a fourth wheel speed, respectively; str denotes a steering wheel angle; yaw represents Yaw acceleration; log represents a longitudinal acceleration; lat represents lateral acceleration.
Step 102: and expanding the training input quantity in the training sample into an 8-by-8 symmetric vehicle real-time data matrix. The symmetric vehicle real-time data matrix is as follows:
【wh1 wh1 wh1 wh1 wh1 wh1 wh1 wh1】
【wh1 wh2 wh2 wh2 wh2 wh2 wh2 wh2】
【wh1 wh2 wh3 wh3 wh3 wh3 wh3 wh3】
【wh1 wh2 wh3 wh4 wh4 wh4 wh4 wh4】
【wh1 wh2 wh3 wh4 str str str str】
【wh1 wh2 wh3 wh4 str yaw yaw yaw】
【wh1 wh2 wh3 wh4 str yaw log log】
【wh1 wh2 wh3 wh4 str yaw log lat】。
step 103: a training output is determined.
And the transverse speed and the longitudinal speed of the vehicle to the ground, which are measured by the double-shaft optical sensor at the same time, are used as training output.
The training output is [ vlat vlog ]; where vlat represents the lateral velocity and vlog represents the longitudinal velocity.
Step 104: and training the convolutional neural network according to the symmetric vehicle real-time data matrix and the training output quantity to obtain a trained convolutional neural network model.
There are two main types of network layers in convolutional neural networks, namely convolutional layers and sampling layers. The convolutional layer is used for extracting various characteristics of the training sample; the sampling layer is used for abstracting the original signal, so that training parameters are greatly reduced, and the degree of overfitting of the model can be reduced.
When the input training input quantity passes through the convolutional layer, the convolutional core of the convolutional layer is calculated in the input training input quantity by a sliding window. Each parameter of the convolution kernel is a weight parameter in the neural network. And multiplying each parameter of the convolution kernel by the data in the corresponding training sample to obtain the result of the convolution layer.
After the convolutional layer outputs the features of the training input quantity, the features are input into the sampling layer for processing in order to further reduce the overfitting degree of the network training parameters and the model. The sampling layer is used for acting on each output characteristic and reducing the size of the output characteristic, and particularly, each output characteristic is processed by adopting a maximum pooling method so as to reduce the size of the output characteristic.
And comparing the data subjected to the final layer of pooling with the output data of the training sample to obtain the approximation degree of each transverse speed and each longitudinal speed, and selecting the most similar result for outputting.
Step 105: acquiring real-time data of a current vehicle; the real-time data of the current vehicle comprises four wheel speeds of the current vehicle, a steering wheel angle of the current vehicle, a yaw acceleration of the current vehicle, a longitudinal acceleration of the current vehicle and a lateral acceleration of the current vehicle.
Step 106: and inputting the real-time data of the current vehicle into the trained convolutional neural network model, and estimating the transverse speed and the longitudinal speed of the current vehicle to the ground.
The method specifically comprises the following steps: converting the real-time data of the current vehicle according to the form of the training input quantity; and inputting the converted real-time data of the current vehicle into the trained convolutional neural network model, and estimating the transverse speed and the longitudinal speed of the current vehicle to the ground.
In order to achieve the purpose, the invention also provides a vehicle speed estimation system based on the neural network.
As shown in fig. 2, a vehicle speed estimation system method provided by the embodiment of the invention includes:
a training sample obtaining module 100, configured to obtain a training sample; the data in the training sample is vehicle real-time data in a precondition test; the vehicle real-time data comprises four wheel speeds, steering wheel angles, yaw acceleration, longitudinal acceleration and lateral acceleration.
And a symmetric vehicle real-time data matrix determining module 200, configured to expand the training input amount in the training sample into an 8 × 8 symmetric vehicle real-time data matrix.
A training output determination module 300 for determining a training output; the training output is the lateral and longitudinal speed of the vehicle over the ground.
And the convolutional neural network training module 400 is configured to train a convolutional neural network according to the symmetric vehicle real-time data matrix and the training output quantity, so as to obtain a trained convolutional neural network model.
A current vehicle real-time data acquisition module 500, configured to acquire real-time data of a current vehicle; the real-time data of the current vehicle comprises four wheel speeds of the current vehicle, a steering wheel angle of the current vehicle, a yaw acceleration of the current vehicle, a longitudinal acceleration of the current vehicle and a lateral acceleration of the current vehicle.
And a current vehicle-to-ground transverse speed and longitudinal speed estimation module 600, configured to input real-time data of the current vehicle into the trained convolutional neural network model, and estimate a transverse speed and a longitudinal speed of the current vehicle to ground.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. For the system disclosed by the embodiment, the description is relatively simple because the system corresponds to the method disclosed by the embodiment, and the relevant points can be referred to the method part for description.
The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.