Unmanned minibus automatic driving system and control method thereof

Abstract

The invention discloses an unmanned bus automatic driving system, and relates to the technical field of unmanned driving, the unmanned bus automatic driving system comprises a sensor module, an intelligent driving controller, a transverse controller, a longitudinal controller, a coordination controller and an execution mechanism, and control parameters can be adjusted in real time according to the actual operation condition of a bus. And transverse and longitudinal coordination control is realized, so that the control precision and the driving stability of the bus under different road conditions are greatly improved. The invention further discloses a control method of the automatic driving system of the unmanned small bus. The control method comprises the following steps: step 1, information acquisition and processing; 2, generating a reference path and a reference vehicle speed; step 3, transverse control; step 4, longitudinal control; 5, carrying out transverse and longitudinal coordination control; and step 6, feedback and adjustment are carried out, the control strategy can be automatically adjusted according to the change of the road curvature, and the bus can keep good driving performance on the roads with different curvatures.

Description

Technical Field

[0001] The present invention relates to the technical field of driverless technology, and particularly to an automatic driving system for a driverless minibus and a control method thereof. Background Art

[0002] In order to better solve problems such as road traffic congestion and traffic accidents, it is necessary to research and develop an automatic driving system for vehicles.

[0003] The invention patent with the publication number CN108919797A discloses an automatic driving system for an electric minibus. The system includes a sensor assembly, an upper-layer computing unit, and an upper-layer vehicle control unit. The sensor assembly transmits the sensed driving environment information of the electric minibus and the self-vehicle position and attitude information to the upper-layer computing unit; the upper-layer computing unit analyzes and makes decisions on the received information, and issues decision instruction information to the upper-layer vehicle control unit; the upper-layer vehicle control unit generates a vehicle control quantity according to the received decision instruction information sent by the upper-layer computing unit and the information collected by the sensor assembly, and sends it to the vehicle VCU, and sends control instructions to each controller actuator. The existing automatic driving system does not clearly mention the coordinated control strategy for the longitudinal and lateral movements of the electric minibus. For the control strategies under different driving conditions (such as straight driving, turning, accelerating, decelerating, obstacle avoidance, etc.), the prior art does not give specific and targeted solutions. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides an automatic driving system for a driverless minibus and a control method thereof, which solve the existing problems.

[0005] To achieve the above objectives, the present invention is realized through the following technical solutions: An automatic driving system for a driverless minibus, comprising:

[0006] A sensor module, configured to collect various data of the minibus during driving through various sensors;

[0007] An intelligent driving controller, configured to receive information from various sensors, and process and analyze this information;

[0008] A lateral controller, configured to receive information such as a reference path, a reference vehicle speed provided by the intelligent driving controller, and the actual vehicle speed and vehicle state feedback by the longitudinal controller, predict the lateral movement state of the vehicle within a future period of time, and output the front wheel steering angle control quantity at the current moment to the steering system in the actuator to achieve the control of the lateral movement of the minibus;

[0009] A longitudinal controller, which is used to receive information such as the target vehicle speed provided by the intelligent driving controller and the lateral position deviation feedback by the lateral controller, and calculates the target driving torque through fuzzy inference and proportional-integral regulation, so as to achieve stable control and tracking of the longitudinal speed of the minibus;

[0010] A coordination controller, which receives the front wheel angle from the lateral controller, the target driving torque from the longitudinal controller, the actual position of the minibus, the lateral deviation, the actual vehicle speed, and the position relationship and trend information between the minibus and the reference path transmitted by the intelligent driving controller, and conducts coordination control;

[0011] An actuator, which is used to execute corresponding actions after receiving the control signal output by the coordination controller, and change the driving state of the minibus.

[0012] Preferably, the sensor module includes a GPS receiver, an inertial measurement unit, a camera, and a radar;

[0013] The GPS receiver is installed on the top of the minibus and is used to obtain the accurate position information of the vehicle in real time, and the positioning accuracy can reach the centimeter level;

[0014] The inertial measurement unit is installed near the vehicle's center of mass and includes an accelerometer and a gyroscope, which are used to measure the vehicle's acceleration, angular velocity and other motion state information, and provide data support for the vehicle's positioning and attitude estimation;

[0015] A plurality of high-definition cameras are installed around the minibus, including front view, rear view, side view, etc., which are used to collect the image information around the vehicle, and realize the detection and recognition of road signs, traffic lights, obstacles, etc.;

[0016] The radar includes a millimeter-wave radar and a lidar, which are installed at the front and side of the vehicle, and are used to detect the distance, speed and other information of the obstacles around the vehicle in real time, and provide a basis for obstacle avoidance and path planning.

[0017] Preferably, the intelligent driving controller includes an information receiving module, a data preprocessing module, a path planning and speed planning module, a lateral position deviation calculation and monitoring module, an instruction generation module, and an instruction output interface module;

[0018] The information receiving module is connected to various sensors (GPS, IMU, camera, radar, etc.) on the vehicle through various interfaces (such as CAN bus, Ethernet, etc.), and receives information such as the vehicle position, speed, acceleration, and surrounding environment in real time. It conducts preliminary format conversion and data verification on the received information to ensure the integrity and accuracy of the information;

[0019] The data preprocessing module uses filtering algorithms (such as Kalman filtering, mean filtering, etc.) to filter the sensor data, remove noise and interference, perform operations such as denoising, distortion correction, and image enhancement on the image data to improve the image quality, perform clustering analysis on the radar data, extract effective obstacle information, and fuse the processed multi-source heterogeneous data to form a unified cognitive model of the vehicle state and the environment;

[0020] Based on the fused vehicle state and environment information, the path planning and speed planning module uses advanced path planning algorithms (such as A algorithm, D algorithm, etc.) to generate a reference path, considering factors such as road topology, traffic rules, obstacle distribution, road curvature, etc., to ensure the safety and feasibility of the path. At the same time, according to the current driving state of the vehicle, road conditions (such as slope, road surface friction coefficient, etc.) and the destination, etc., algorithms such as model predictive control (MPC) are used for speed planning to generate a reference vehicle speed to optimize the vehicle driving efficiency and comfort;

[0021] The lateral position deviation calculation and monitoring module calculates the lateral position deviation between the minibus and the reference path in real time. By comparing with a preset threshold, it judges whether a lateral deviation occurs. If the deviation exceeds the threshold, it further analyzes the deviation trend and the position relationship between the vehicle and the reference path, and transmits this information to the coordination controller;

[0022] The instruction generation module generates control instructions such as a reference path and a reference vehicle speed according to the results of path planning and speed planning, and encapsulates them in a standard data format for easy transmission and use by other modules;

[0023] The instruction output interface module provides communication interfaces with the lateral controller and the longitudinal controller, and accurately and timely sends the generated control instructions such as the reference path and the reference vehicle speed to the corresponding controllers to ensure the coordinated operation of the system.

[0024] Preferably, the lateral controller includes a reference path and vehicle speed receiving module, a vehicle state information receiving module, a data preprocessing module, a lateral dynamics model establishment module, an LTV_MPC algorithm calculation module, and a control quantity output module;

[0025] The reference path and vehicle speed receiving module receives the reference path and reference vehicle speed information through the communication interface with the intelligent driving controller, parses and verifies the data to ensure the correctness and integrity of the data;

[0026] The vehicle state information receiving module receives the actual vehicle speed and vehicle state (such as acceleration, yaw rate, etc.) information fed back by the longitudinal controller, and also performs data parsing and verification to provide comprehensive vehicle dynamic information for the lateral control algorithm;

[0027] The data preprocessing module preprocesses the received reference path and vehicle state information, such as coordinate transformation, data interpolation, etc., to make it meet the input requirements of the lateral control algorithm, improving the computational efficiency and accuracy of the algorithm;

[0028] The lateral dynamics model establishment module establishes an accurate vehicle lateral dynamics model based on the physical parameters of the vehicle (mass, moment of inertia, tire cornering stiffness, etc.) and kinematic characteristics, serving as the basis for the lateral control algorithm;

[0029] The LTV_MPC algorithm calculation module inputs the preprocessed reference path, reference vehicle speed, actual vehicle speed, and vehicle state information into the LTV_MPC algorithm. By solving the finite-time optimization problem, it calculates the front wheel angle control sequence that minimizes the vehicle lateral motion error. The objective function of the optimization problem comprehensively considers factors such as vehicle lateral position error, heading angle error, and front wheel angle change rate. The constraint conditions include the maximum front wheel angle and maximum lateral acceleration of the vehicle to ensure the safety and comfort of control;

[0030] The control quantity output module extracts the front wheel angle control quantity at the current moment from the calculated front wheel angle control sequence and outputs it to the steering system through the interface with the actuator to achieve precise control of the lateral motion of the minibus.

[0031] Preferably, the longitudinal controller includes a target vehicle speed receiving module, a lateral position deviation receiving module, a vehicle state information receiving module, a data preprocessing module, a fuzzy controller design module, an Fuzzy-PI algorithm calculation module, and a control quantity output module;

[0032] The target vehicle speed receiving module receives the target vehicle speed information from the intelligent driving controller, performs data parsing and verification to ensure the accuracy of the data;

[0033] The lateral position deviation receiving module receives the lateral position deviation information fed back by the lateral controller and also performs data processing to make it meet the input requirements of the longitudinal control algorithm;

[0034] The vehicle state information receiving module receives the actual vehicle speed, acceleration and other state information of the vehicle to provide real-time vehicle dynamic data for longitudinal control;

[0035] The data preprocessing module preprocesses the received target vehicle speed, lateral position deviation and vehicle state information, such as normalization, filtering, etc., to improve the data quality and provide reliable input for the longitudinal control algorithm;

[0036] The fuzzy controller design module defines the input variables (vehicle speed deviation and vehicle speed deviation change rate) and output variables (adjustment amounts of the proportional coefficient and integral coefficient) of the fuzzy controller. According to expert experience and experimental data, it designs a fuzzy control rule table, establishes the fuzzy relationship between input and output, and realizes the intelligent control of the vehicle speed;

[0037] The Fuzzy-PI algorithm calculation module obtains the adjustment amounts of the proportional coefficient and integral coefficient through fuzzy inference and defuzzification based on the deviation between the current vehicle speed and the target vehicle speed and the change rate of the deviation, and then calculates the target driving torque. This calculation process takes into account the dynamic characteristics and control requirements of the vehicle to achieve stable tracking of the vehicle speed and good dynamic performance;

[0038] The control quantity output module outputs the calculated target driving torque to the drive system through the interface with the actuator, controls the output torque of the drive motor, and realizes the precise control of the longitudinal movement of the minibus to ensure that the vehicle travels at the reference vehicle speed.

[0039] Preferably, the coordination controller includes a lateral controller information receiving module, a longitudinal controller information receiving module, a vehicle state information receiving module, a position relationship and trend information receiving module, an additional driving torque calculation module, a coordination rule judgment and execution module, and a control signal output interface unit;

[0040] The lateral controller information receiving module receives the front wheel steering angle information from the lateral controller, performs data parsing and verification to ensure the accuracy and timeliness of the data;

[0041] The longitudinal controller information receiving module receives the target driving torque information of the longitudinal controller and also performs data processing to ensure the reliability of the data;

[0042] The vehicle state information receiving module receives information such as the actual position, lateral deviation, and actual vehicle speed of the minibus, providing comprehensive vehicle operating state data for coordinated control;

[0043] The position relationship and trend information receiving module receives the position relationship and trend information between the minibus and the reference path transmitted by the intelligent driving controller, parses and stores this information for subsequent formulation and execution of coordination rules;

[0044] The data preprocessing module preprocesses various received information, such as data format conversion, consistency check, etc., to ensure that all input information can be effectively used by the coordinated control algorithm;

[0045] The additional driving torque calculation module calculates an additional driving torque T1 through algorithms such as a PID controller based on the actual position and lateral deviation of the minibus. This calculation process takes into account the magnitude and direction of the vehicle's lateral deviation as well as the vehicle's dynamic characteristics to effectively coordinate the longitudinal and lateral movements of the vehicle;

[0046] The coordination law judgment and execution module makes judgments and executions according to the received position relationship and trend information between the minibus and the reference path according to the preset coordination law;

[0047] The control signal output interface unit provides a communication interface with the actuator, and accurately and timely sends control signals such as the coordinated final driving torque and front wheel angle to the actuator to achieve coordinated control of the longitudinal and lateral movements of the minibus.

[0048] Preferably, the actuator includes a steering system execution unit and a drive system execution unit;

[0049] The steering system execution unit includes a front wheel angle receiving module, a steering motor drive module, and a feedback and monitoring module;

[0050] The front wheel angle receiving module receives the front wheel angle control signal through the communication interface with the coordination controller, performs data parsing and verification to ensure the accuracy and reliability of the signal;

[0051] The steering motor drive module drives the steering motor to rotate according to the received front wheel angle control signal, and precisely controls the front wheel angle of the vehicle through mechanical structures such as the steering column and steering gear to implement the lateral movement of the minibus;

[0052] The feedback and monitoring module real-time monitors the working state of the steering motor (such as current, voltage, speed, etc.) and the actual angle of the front wheel, and feeds this information back to the lateral controller and the coordination controller to form a closed-loop control to improve the control accuracy and stability;

[0053] The drive system execution unit includes a driving torque receiving module, a motor controller, and a power battery management module;

[0054] The driving torque receiving module receives the final driving torque signal output by the coordination controller, performs data parsing and verification to ensure the correctness and integrity of the signal;

[0055] The motor controller controls the output torque of the drive motor according to the received driving torque signal to achieve the acceleration, deceleration, and uniform speed driving of the vehicle. The motor controller adopts advanced control strategies (such as vector control, direct torque control, etc.) to ensure the efficient and stable operation of the drive motor;

[0056] The power battery management module monitors the status of the power battery in real time (such as voltage, current, SOC, etc.), and performs energy management and distribution according to the power demand of the vehicle and the battery status to ensure the endurance and power performance of the vehicle. At the same time, it feeds back the battery status information to the intelligent driving controller and other relevant modules to provide reference for the overall control of the system.

[0057] The present invention also discloses a control method for an autonomous driving system of a driverless minibus, including the following steps:

[0058] Step 1, information collection and processing: The intelligent driving controller collects information such as the position, speed, acceleration, and surrounding environment of the vehicle in real time through various sensor modules installed on the minibus, preprocesses the collected information, and simultaneously calculates the lateral position deviation between the minibus and the reference path in real time, and judges the position relationship and trend between the minibus and the reference path, and transmits this information to the coordination controller;

[0059] Step 2, generating a reference path and a reference vehicle speed: Based on the preprocessed vehicle position and surrounding environment information, the intelligent driving controller generates a reference path using a path planning algorithm, and simultaneously generates a reference vehicle speed through a speed planning algorithm to provide a target speed reference for the lateral controller and the longitudinal controller;

[0060] Step 3, lateral control: The lateral controller receives the reference path, reference vehicle speed provided by the intelligent driving controller, and information such as the actual vehicle speed and vehicle status feedback from the longitudinal controller, predicts the lateral motion state of the vehicle in the next period of time, and outputs the front wheel steering angle control amount at the current moment to the steering system in the actuator to realize the control of the lateral motion of the minibus;

[0061] Step 4, longitudinal control: The longitudinal controller receives the target vehicle speed provided by the intelligent driving controller and information such as the lateral position deviation feedback from the lateral controller, calculates the target driving torque through fuzzy inference and proportional-integral regulation, and simultaneously controls the drive system in the actuator to realize the stable control and tracking of the longitudinal speed of the minibus;

[0062] Step 5, lateral and longitudinal coordination control: The coordination controller receives the front wheel steering angle from the lateral controller, the target driving torque from the longitudinal controller, the actual position of the minibus, the lateral deviation, the actual vehicle speed, and the position relationship and trend information between the minibus and the reference path transmitted by the intelligent driving controller, and performs corresponding processing according to the coordination rule when the minibus is in different working conditions;

[0063] Step 6: Feedback and Adjustment: After the actuator receives the control signal output by the coordination controller, it performs corresponding actions to change the driving state of the minibus. At the same time, the sensor real-time monitors information such as the actual position, speed, and lateral deviation of the vehicle, and feeds this information back to the intelligent driving controller, lateral controller, and longitudinal controller. Each controller adjusts the control strategy and parameters in real time according to the feedback information to form a closed-loop control.

[0064] Beneficial Effects

[0065] The present invention provides an autonomous driving system for a driverless minibus and its control method. Compared with the prior art, it has the following beneficial effects:

[0066] 1. For the autonomous driving system of the driverless minibus, by constructing a coordination control system, the lateral controller and the longitudinal controller are combined, fully considering the coupling relationship between the lateral and longitudinal directions. It can adjust the control parameters in real time according to the actual operating conditions of the minibus, achieving coordinated control of the lateral and longitudinal directions. Thus, it greatly improves the control accuracy and driving stability of the minibus under different road conditions, effectively avoiding the control errors and instability phenomena that may occur when using only the lateral or longitudinal control system. At the same time, more precise control is carried out in combination with the position relationship and trend between the minibus and the reference path, further enhancing the control effect.

[0067] 2. For the control method of the autonomous driving system of the driverless minibus, it can automatically adjust the control strategy according to the change of road curvature, enabling the minibus to maintain good driving performance on roads with different curvatures. Whether it is a straight road, a small-curvature bend, or a large-curvature bend, the system can, through the action of the coordination controller, reasonably distribute the front-wheel steering angle and driving torque to ensure that the vehicle can pass smoothly and safely, improving the adaptability of the driverless minibus to complex road environments. And, for different situations between the minibus and the reference path on roads with different curvatures, targeted control is carried out, enhancing the adaptability to various road scenarios. Description of the Drawings

[0068] Figure 1 It is a schematic diagram of the system connection of the present invention;

[0069] Figure 2 It is a schematic diagram of the lateral and longitudinal coordinated control strategy of the present invention;

[0070] Figure 3 It is a schematic diagram of the method flow of the present invention;

[0071] Figure 4 It is the actual driving condition of the present invention Figure 1 ;

[0072] Figure 5 It is the actual driving condition of the present invention Figure 2 ;

[0073] Figure 6 for the actual driving condition of the present invention Figure 3 ;

[0074] Figure 7 for the actual driving condition of the present invention Figure 4 ;

[0075] Figure 8 is the schematic diagram of the longitudinal and lateral coordination control of the present invention. Detailed implementation manners

[0076] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0077] Refer to Figure 1-8 , the present invention provides three technical solutions:

[0078] The first implementation manner: An autonomous driving system for a driverless minibus, comprising:

[0079] A sensor module for collecting various data of the minibus during driving through various sensors;

[0080] The sensor module includes a GPS receiver, an inertial measurement unit, a camera, and a radar;

[0081] The GPS receiver is installed on the top of the minibus for real-time acquisition of the accurate position information of the vehicle, and the positioning accuracy can reach the centimeter level;

[0082] The inertial measurement unit is installed near the vehicle's center of mass and includes an accelerometer and a gyroscope for measuring the vehicle's acceleration, angular velocity and other motion state information, providing data support for the vehicle's positioning and attitude estimation;

[0083] A plurality of high-definition cameras are installed around the minibus, including front view, rear view, side view, etc., for collecting the image information around the vehicle to realize the detection and recognition of road signs, traffic lights, obstacles, etc.;

[0084] The radar includes a millimeter-wave radar and a lidar, which are installed at the front and side of the vehicle for real-time detection of the distance, speed and other information of the obstacles around the vehicle, providing a basis for obstacle avoidance and path planning.

[0085] An intelligent driving controller for receiving information from various sensors and processing and analyzing this information;

[0086] The intelligent driving controller includes an information receiving module, a data preprocessing module, a path planning and speed planning module, a lateral position deviation calculation and monitoring module, an instruction generation module, and an instruction output interface module;

[0087] The information receiving module is connected to various sensors (such as GPS, IMU, cameras, radars, etc.) on the vehicle through multiple interfaces (such as CAN bus, Ethernet, etc.), and receives information such as vehicle position, speed, acceleration, and surrounding environment in real time. It performs preliminary format conversion and data verification on the received information to ensure the integrity and accuracy of the information;

[0088] The data preprocessing module uses filtering algorithms (such as Kalman filtering, mean filtering, etc.) to filter the sensor data, remove noise and interference, perform operations such as denoising, distortion correction, and image enhancement on the image data to improve the image quality, perform clustering analysis on the radar data, extract effective obstacle information, and fuse the processed multi-source heterogeneous data to form a unified cognitive model of the vehicle state and environment;

[0089] Based on the fused vehicle state and environment information, the path planning and speed planning module uses advanced path planning algorithms (such as A algorithm, D algorithm, etc.) to generate a reference path, considering factors such as road topology, traffic rules, obstacle distribution, and road curvature to ensure the safety and feasibility of the path. At the same time, according to the current driving state of the vehicle, road conditions (such as slope, road surface friction coefficient, etc.), and destination, etc., it uses algorithms such as model predictive control (MPC) for speed planning to generate a reference vehicle speed to optimize the vehicle driving efficiency and comfort;

[0090] The lateral position deviation calculation and monitoring module calculates the lateral position deviation between the minibus and the reference path in real time. By comparing with a preset threshold, it determines whether a lateral deviation occurs. If the deviation exceeds the threshold, it further analyzes the deviation trend and the position relationship between the vehicle and the reference path, and transmits this information to the coordination controller;

[0091] The instruction generation module generates control instructions such as a reference path and a reference vehicle speed according to the path planning and speed planning results, and encapsulates them in a standard data format for easy transmission and use by other modules;

[0092] The instruction output interface module provides communication interfaces with the lateral controller and the longitudinal controller, and accurately and timely sends the generated control instructions such as the reference path and the reference vehicle speed to the corresponding controllers to ensure the coordinated operation of the system.

[0093] A lateral controller is used to receive information such as the reference path, reference vehicle speed provided by the intelligent driving controller, and the actual vehicle speed and vehicle state feedback from the longitudinal controller, predict the lateral motion state of the vehicle in the next period of time, and output the front wheel steering angle control amount at the current moment to the steering system in the actuator to achieve the control of the lateral motion of the minibus;

[0094] The lateral controller includes a reference path and vehicle speed receiving module, a vehicle state information receiving module, a data preprocessing module, a lateral dynamics model establishment module, an LTV_MPC algorithm calculation module, and a control amount output module;

[0095] The reference path and vehicle speed receiving module receives the reference path and reference vehicle speed information through the communication interface with the intelligent driving controller, parses and verifies the data to ensure the correctness and integrity of the data;

[0096] The vehicle state information receiving module receives the actual vehicle speed and vehicle state (such as acceleration, yaw rate, etc.) information feedback from the longitudinal controller, and also performs data parsing and verification to provide comprehensive vehicle dynamic information for the lateral control algorithm;

[0097] The data preprocessing module preprocesses the received reference path and vehicle state information, such as coordinate transformation, data interpolation, etc., to make it meet the input requirements of the lateral control algorithm and improve the calculation efficiency and accuracy of the algorithm;

[0098] The lateral dynamics model establishment module establishes an accurate vehicle lateral dynamics model based on the physical parameters (mass, moment of inertia, tire cornering stiffness, etc.) and kinematic characteristics of the vehicle, which serves as the basis for the lateral control algorithm;

[0099] The LTV_MPC algorithm calculation module inputs the preprocessed reference path, reference vehicle speed, actual vehicle speed, and vehicle state information into the LTV_MPC algorithm. By solving the optimization problem in the finite time domain, it calculates the front wheel steering angle control sequence that minimizes the lateral motion error of the vehicle. The objective function of the optimization problem comprehensively considers factors such as vehicle lateral position error, heading angle error, and front wheel steering angle change rate. The constraint conditions include the maximum front wheel steering angle, maximum lateral acceleration of the vehicle, etc., to ensure the safety and comfort of the control;

[0100] The control amount output module extracts the front wheel steering angle control amount at the current moment from the calculated front wheel steering angle control sequence and outputs it to the steering system through the interface with the actuator to achieve the precise control of the lateral motion of the minibus.

[0101] A longitudinal controller is used to receive information such as the target vehicle speed provided by the intelligent driving controller and the lateral position deviation feedback from the lateral controller. Through fuzzy inference and proportional-integral regulation, it calculates the target driving torque to achieve stable control and tracking of the longitudinal speed of the minibus.

[0102] The longitudinal controller includes a target vehicle speed receiving module, a lateral position deviation receiving module, a vehicle state information receiving module, a data preprocessing module, a fuzzy controller design module, a Fuzzy-PI algorithm calculation module, and a control quantity output module.

[0103] The target vehicle speed receiving module receives the target vehicle speed information from the intelligent driving controller, performs data parsing and verification to ensure the accuracy of the data.

[0104] The lateral position deviation receiving module receives the lateral position deviation information feedback from the lateral controller and also performs data processing to make it meet the input requirements of the longitudinal control algorithm.

[0105] The vehicle state information receiving module receives the actual vehicle speed, acceleration and other state information of the vehicle to provide real-time vehicle dynamic data for longitudinal control.

[0106] The data preprocessing module preprocesses the received target vehicle speed, lateral position deviation and vehicle state information, such as normalization, filtering, etc., to improve the data quality and provide reliable input for the longitudinal control algorithm.

[0107] The fuzzy controller design module defines the input variables (vehicle speed deviation and vehicle speed deviation change rate) and output variables (adjustment amounts of the proportional coefficient and integral coefficient) of the fuzzy controller. According to expert experience and experimental data, it designs a fuzzy control rule table to establish the fuzzy relationship between input and output, and realizes the intelligent control of the vehicle speed.

[0108] The Fuzzy-PI algorithm calculation module, based on the deviation between the current vehicle speed and the target vehicle speed and the change rate of the deviation, through fuzzy inference and defuzzification, obtains the adjustment amounts of the proportional coefficient and integral coefficient, and then calculates the target driving torque. This calculation process takes into account the dynamic characteristics and control requirements of the vehicle to achieve stable tracking of the vehicle speed and good dynamic performance.

[0109] The control quantity output module outputs the calculated target driving torque to the drive system through the interface with the actuator, controls the output torque of the drive motor, and realizes the precise control of the longitudinal movement of the minibus to ensure that the vehicle travels at the reference vehicle speed.

[0110] A coordination controller receives the front wheel angle from the lateral controller, the target driving torque from the longitudinal controller, the actual position of the minibus, the lateral deviation, the actual vehicle speed, and the position relationship and trend information between the minibus and the reference path transmitted by the intelligent driving controller, and performs coordination control.

[0111] The coordination controller includes a lateral controller information receiving module, a longitudinal controller information receiving module, a vehicle state information receiving module, a position relationship and trend information receiving module, an additional driving torque calculation module, a coordination rule judgment and execution module, and a control signal output interface unit;

[0112] The lateral controller information receiving module receives the front wheel steering angle information from the lateral controller, performs data parsing and verification to ensure the accuracy and timeliness of the data;

[0113] The longitudinal controller information receiving module receives the target driving torque information from the longitudinal controller and also performs data processing to ensure the reliability of the data;

[0114] The vehicle state information receiving module receives information such as the actual position, lateral deviation, and actual vehicle speed of the minibus, providing comprehensive vehicle operation state data for coordinated control;

[0115] The position relationship and trend information receiving module receives the position relationship and trend information between the minibus and the reference path transmitted by the intelligent driving controller, parses and stores this information for subsequent formulation and execution of coordination rules;

[0116] The data preprocessing module preprocesses various received information, such as data format conversion, consistency check, etc., to ensure that all input information can be effectively used by the coordinated control algorithm;

[0117] The additional driving torque calculation module calculates an additional driving torque T1 based on the actual position and lateral deviation of the minibus through algorithms such as a PID controller. This calculation process takes into account the magnitude and direction of the vehicle's lateral deviation as well as the vehicle's dynamic characteristics to achieve effective coordination of the vehicle's longitudinal and lateral movements;

[0118] The coordination rule judgment and execution module makes judgments and executions according to the received position relationship and trend information between the minibus and the reference path in accordance with the preset coordination rules;

[0119] The control signal output interface unit provides a communication interface with the actuator, and accurately and timely sends control signals such as the coordinated final driving torque and front wheel steering angle to the actuator to achieve coordinated control of the longitudinal and lateral movements of the minibus.

[0120] The actuator is used to perform corresponding actions after receiving the control signal output by the coordination controller, changing the driving state of the minibus;

[0121] The actuator includes a steering system execution unit and a drive system execution unit;

[0122] The steering system execution unit includes a front wheel angle receiving module, a steering motor drive module, and a feedback and monitoring module;

[0123] The front wheel angle receiving module receives the front wheel angle control signal through the communication interface with the coordination controller, performs data parsing and verification to ensure the accuracy and reliability of the signal;

[0124] The steering motor drive module drives the steering motor to rotate according to the received front wheel angle control signal, and precisely controls the front wheel angle of the vehicle through mechanical structures such as the steering column and steering gear, so as to execute the lateral movement of the minibus;

[0125] The feedback and monitoring module monitors the working state of the steering motor (such as current, voltage, speed, etc.) and the actual angle of the front wheels in real time, and feeds this information back to the lateral controller and the coordination controller to form a closed-loop control, improving the control accuracy and stability;

[0126] The drive system execution unit includes a driving torque receiving module, a motor controller, and a power battery management module;

[0127] The driving torque receiving module receives the final driving torque signal output by the coordination controller, performs data parsing and verification to ensure the correctness and integrity of the signal;

[0128] The motor controller controls the output torque of the drive motor according to the received driving torque signal to achieve the acceleration, deceleration, and uniform driving of the vehicle. The motor controller adopts advanced control strategies (such as vector control, direct torque control, etc.) to ensure the efficient and stable operation of the drive motor;

[0129] The power battery management module monitors the state of the power battery (such as voltage, current, SOC

[0130] etc.) in real time, performs energy management and distribution according to the power demand of the vehicle and the battery state to ensure the endurance and power performance of the vehicle. At the same time, it feeds back the battery state information to the intelligent driving controller and other relevant modules to provide reference for the overall control of the system.

[0131] The second implementation manner: The present invention also discloses a control method for an autonomous driving system of an unmanned minibus, including the following steps:

[0132] Step 1. Information Acquisition and Processing: The intelligent driving controller collects information such as the vehicle's position, speed, acceleration, and surrounding environment in real time through various sensors installed on the minibus, such as GPS (Global Positioning System), inertial measurement unit (IMU), cameras, radars, etc. The collected information is preprocessed, including data filtering, coordinate transformation, obstacle detection and recognition, etc., to remove noise and interference, extract useful information, and store the processed information in the system's memory for subsequent control algorithms. At the same time, the intelligent driving controller calculates the lateral position deviation between the minibus and the reference path in real time, judges the position relationship and trend between the minibus and the reference path, and transmits this information to the coordination controller;

[0133] Step 2. Generate Reference Path and Reference Speed: Based on the preprocessed vehicle position and surrounding environment information, the intelligent driving controller uses a path planning algorithm to generate a reference path. The path planning algorithm takes into account factors such as road topology, traffic rules, and obstacle distribution to ensure that the generated reference path is safe, feasible, and efficient. At the same time, according to the vehicle's current driving state, road conditions, and destination information, the intelligent driving controller generates a reference speed through a speed planning algorithm to provide a target speed reference for the lateral controller and the longitudinal controller;

[0134] Step 3. Lateral Control: The lateral controller receives the reference path, reference speed provided by the intelligent driving controller, and the actual vehicle speed and vehicle state feedback by the longitudinal controller. Using the LTV_MPC algorithm, the lateral controller establishes the lateral dynamic model of the vehicle, predicts the lateral motion state of the vehicle in the next period of time, and through an optimization algorithm, solves the front-wheel steering angle control sequence that minimizes the lateral motion error of the vehicle, and outputs the front-wheel steering angle control amount at the current moment to the steering system in the actuator to achieve the control of the lateral motion of the minibus and make it accurately follow the reference path;

[0135] Step 4. Longitudinal Control: The longitudinal controller receives the target vehicle speed provided by the intelligent driving controller and the lateral position deviation feedback by the lateral controller. Using the Fuzzy-PI control algorithm, the longitudinal controller calculates the target driving torque according to the deviation between the current vehicle speed and the target vehicle speed and the change rate of the deviation through fuzzy inference and proportional-integral adjustment. This target driving torque is used to control the drive system in the actuator to achieve stable control and tracking of the longitudinal speed of the minibus, make it able to drive according to the reference speed, and maintain good dynamic performance and comfort under different road conditions;

[0136] Step 5. Lateral and longitudinal coordinated control: The coordination controller receives the front wheel steering angle from the lateral controller, the target driving torque from the longitudinal controller, the actual position of the minibus, the lateral deviation, the actual vehicle speed, and the position relationship and trend information between the minibus and the reference path transmitted by the intelligent driving controller. According to the above coordination rules, corresponding processing is performed when the minibus is in different working conditions:

[0137] If it is determined that there is a lateral position deviation between the minibus and the reference path and the minibus is moving away from the reference path (such as the situations shown in Figure 4 and Figure 7 ), first, an additional driving torque T1 is calculated by the PID controller. Then, the target driving torque calculated by the longitudinal controller is subtracted by the additional driving torque T1 to obtain the final driving torque, which is output to the actuator together with the front wheel steering angle. At the same time, the vehicle is controlled to decelerate so that the minibus can quickly track the reference path under the action of lateral control;

[0138] If it is determined that there is a lateral position deviation between the minibus and the reference path and the minibus is moving towards the reference path (such as the situations shown in Figure 5 and Figure 6 ), similarly, an additional driving torque T1 is calculated by the PID controller first. Then, the target driving torque calculated by the longitudinal controller is added by the additional driving torque T1 to obtain the final driving torque, which is output to the actuator together with the front wheel steering angle. At the same time, the vehicle is controlled to accelerate so that the minibus can quickly track the reference path;

[0139] Step 6. Feedback and adjustment: After receiving the control signal output by the coordination controller, the actuator performs corresponding actions to change the driving state of the minibus. At the same time, the sensor real-time monitors information such as the actual position, speed, and lateral deviation of the vehicle, and feeds back this information to the intelligent driving controller, lateral controller, and longitudinal controller. Each controller adjusts the control strategy and parameters in real time according to the feedback information, forming a closed-loop control system to ensure that the minibus can accurately and stably travel along the predetermined path and speed, realizing the autonomous driving function.

[0140] The path tracking system of the driverless minibus mainly consists of a path recognition module, a lateral deviation detection module, a PID controller, a coordination controller, and a power control system. The path recognition module is used to obtain the reference path information in real time. The lateral deviation detection module is responsible for monitoring the lateral position deviation ΔY between the minibus and the reference path. The PID controller calculates the additional driving torque T1 according to the lateral deviation. The coordination controller determines the adjustment method of the target driving torque based on the position of the minibus and the relative trend with the reference path. Finally, the power control system performs corresponding power adjustments to achieve the fast and stable tracking of the minibus to the reference path.

[0141] In the above embodiments, lateral deviation detection and judgment are performed.

[0142] Lateral deviation detection: The lateral deviation detection module in the system continuously monitors the lateral position relationship between the small bus and the reference path, and obtains the lateral position deviation ΔY in real time. For example, in Figure 4 - Figure 7 the four actual driving conditions shown, the lateral position deviation between the small bus and the reference path can be accurately detected;

[0143] Judgment of whether lateral deviation occurs: First, judge whether the lateral deviation ΔY exceeds a certain value γ. If it exceeds, it is considered that lateral deviation has occurred. For example, when ΔY > γ, the system determines that the small bus has a lateral position deviation, as in Figure 4 where the small bus significantly deviates from the reference path, meeting this condition.

[0144] In the above embodiments, judgment of the relative position and trend of the reference path:

[0145] Judgment of the relative position of the reference path: Determine on which side of the small bus the reference path is. Use the angle at the intersection of the predicted direction edge of the vehicle speed v and the radius r and the reference path to assist in the judgment. If then the reference path is on the left side of the small bus; if then the reference path is on the right side of the small bus. For example, in Figure 4 the angle indicates that the reference path is on the left side of the small bus; in Figure 5 the angle shows that the reference path is on the right side of the small bus.

[0146] Judgment of the trend of approaching or departing from the reference path: According to the relative position of the reference path and the positive or negative of the angle , judge whether the small bus has a trend of departing from or approaching the reference path. If it is on the left side and is positive, the small bus has a trend of departing from the reference path, as shown in Figure 4 ; if it is on the left side and is negative, the small bus has a trend of approaching the reference path, as shown in Figure 6 ; if it is on the right side and is negative, the small bus has a trend of approaching the reference path, as shown in Figure 5 ; if it is on the right side and is positive, the small bus has a trend of departing from the reference path, as shown in Figure 7 .

[0147] In the above embodiments, a driving torque adjustment strategy is carried out

[0148] Additional driving torque calculation: When it is determined that a lateral deviation occurs, the lateral deviation ΔY is input into the PID controller, and the PID controller calculates an additional driving torque T1.

[0149] Target driving torque adjustment: Adjust the target driving torque T according to the judgment of the coordination controller.

[0150] When far from the reference path: When there is a lateral position deviation between the small bus and the reference path and it is far from the reference path (such as in working conditions Figure 4 and Figure 7 ), it should be appropriately decelerated, that is, the target driving torque T minus the additional driving torque T1 (T - T1), so that the small bus can track the reference path as soon as possible under the action of lateral control. For example, in Figure 4 , the reference path is on the left side of the small bus and the small bus has a tendency to move away. At this time, a deceleration operation should be performed to reduce the driving torque.

[0151] When approaching the reference path: When there is a lateral position deviation between the small bus and the reference path and it is approaching the reference path (such as in working conditions Figure 5 and Figure 6 ), it should be appropriately accelerated, that is, the target driving torque T plus the additional driving torque T1 (T - T1), so that the small bus can quickly track the reference path. For example, in Figure 6 , the reference path is on the left side of the small bus and the small bus has a tendency to approach. At this time, the driving torque needs to be increased to accelerate the tracking.

[0152] The third implementation method: In order to verify the effectiveness and superiority of the unmanned small bus automatic driving system and its control method of the present invention, a series of experimental tests were carried out. The experiments were carried out in a closed test site, where curves with different curvatures, straight roads, slopes, and various obstacles were set up to simulate the actual road environment.

[0153] A modified unmanned small bus was used as the experimental vehicle, and the vehicle was equipped with the above-mentioned sensor, intelligent driving controller, actuator and other system hardware.

[0154] The sampling frequencies of the sensors were set as follows: GPS was 10Hz, IMU was 100Hz, the camera was 30fps, and the radar was 20Hz.

[0155] The prediction horizon of the lateral controller was set to 5s, and the control horizon was set to 1s; the quantization factor and scale factor of the fuzzy controller of the longitudinal controller were determined according to experimental debugging to obtain the best control performance; the coordination controller was used to judge the position of the small bus and the reference path.

[0156] At the same time, the content not described in detail in this specification belongs to the prior art well-known to those skilled in the art, and the model parameters of each electrical appliance are not specifically limited, and conventional equipment can be used.

[0157] It should be noted that, in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variation thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0158] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An autonomous driving system for a driverless minibus, characterized in that, Including: A sensor module for collecting various data of the minibus during driving through various sensors; An intelligent driving controller for receiving information from various sensors and processing and analyzing this information; A lateral controller for receiving the reference path, reference vehicle speed provided by the intelligent driving controller, and the actual vehicle speed and vehicle state information fed back by the longitudinal controller, predicting the lateral motion state of the vehicle within a future period of time, and outputting the front wheel steering angle control amount at the current moment to the steering system in the actuator to achieve the control of the lateral motion of the minibus; A longitudinal controller for receiving the target vehicle speed provided by the intelligent driving controller and the lateral position deviation information fed back by the lateral controller, and calculating the target driving torque through fuzzy inference and proportional-integral regulation to achieve the stable control and tracking of the longitudinal speed of the minibus; A coordination controller for receiving the front wheel steering angle from the lateral controller, the target driving torque from the longitudinal controller, the actual position of the minibus, the lateral deviation, the actual vehicle speed, and the position relationship and trend information between the minibus and the reference path transmitted by the intelligent driving controller to perform coordination control; An actuator for performing corresponding actions after receiving the control signal output by the coordination controller to change the driving state of the minibus.

2. The autonomous driving system of a driverless minibus according to claim 1, wherein: The sensor module includes a GPS receiver, an inertial measurement unit, a camera, and a radar.

3. The autonomous driving system of a driverless minibus according to claim 1, characterized in that: The intelligent driving controller includes an information receiving module, a data preprocessing module, a path planning and speed planning module, a lateral position deviation calculation and monitoring module, an instruction generation module, and an instruction output interface module.

4. The autonomous driving system of a driverless minibus according to claim 1, wherein: The lateral controller includes a reference path and vehicle speed receiving module, a vehicle state information receiving module, a data preprocessing module, a lateral dynamics model establishment module, an LTV_MPC algorithm calculation module, and a control amount output module.

5. The autonomous driving system of a driverless minibus according to claim 1, characterized in that: The longitudinal controller includes a target vehicle speed receiving module, a lateral position deviation receiving module, a vehicle state information receiving module, a data preprocessing module, a fuzzy controller design module, a Fuzzy-PI algorithm calculation module, and a control amount output module.

6. The automatic driving system of a driverless minibus according to claim 1, characterized in that: The coordination controller includes a lateral controller information receiving module, a longitudinal controller information receiving module, a vehicle state information receiving module, a position relationship and trend information receiving module, a data preprocessing module, an additional driving torque calculation module, a coordination rule judgment and execution module, and a control signal output interface unit.

7. The automatic driving system for a driverless minibus according to claim 1, characterized in that: The actuator includes a steering system execution unit and a drive system execution unit; The steering system execution unit includes a front wheel steering angle receiving module, a steering motor drive module, and a feedback and monitoring module; The drive system execution unit includes a driving torque receiving module, a motor controller, and a power battery management module.

8. A control method for an automatic driving system of a driverless minibus, based on the automatic driving system of a driverless minibus described in claims 1-7, characterized in that, Including the following steps: Step 1, Information acquisition and processing: The intelligent driving controller collects the position, speed, acceleration, and surrounding environment information of the vehicle in real time through various sensor modules installed on the minibus, preprocesses the collected information, calculates the lateral position deviation between the minibus and the reference path in real time, and judges the position relationship and trend between the minibus and the reference path, and transmits this information to the coordination controller; Step 2: Generate reference path and reference vehicle speed: Based on the preprocessed vehicle position and surrounding environment information, the intelligent driving controller uses the path planning algorithm to generate a reference path, and at the same time generates a reference vehicle speed through the speed planning algorithm to provide a target speed reference for the lateral controller and the longitudinal controller; Step 3: Lateral control: The lateral controller receives the reference path, reference vehicle speed provided by the intelligent driving controller, as well as the information of the actual vehicle speed and vehicle state feedback from the longitudinal controller, predicts the lateral motion state of the vehicle in the next period of time, and outputs the front wheel steering angle control amount at the current moment to the steering system in the actuator to achieve the control of the lateral motion of the minibus; Step 4: Longitudinal control: The longitudinal controller receives the target vehicle speed provided by the intelligent driving controller and the information of the lateral position deviation feedback from the lateral controller, calculates the target driving torque through fuzzy inference and proportional-integral regulation, and at the same time controls the drive system in the actuator to achieve the stable control and tracking of the longitudinal speed of the minibus; Step 5: Lateral and longitudinal coordinated control: The coordination controller receives the front wheel steering angle from the lateral controller, the target driving torque from the longitudinal controller, the actual position of the minibus, the lateral deviation, the actual vehicle speed, and the position relationship and trend information between the minibus and the reference path transmitted by the intelligent driving controller, and according to the coordination rules, performs corresponding processing when the minibus is in different working conditions; Step 6: Feedback and adjustment: After receiving the control signal output by the coordination controller, the actuator performs corresponding actions to change the driving state of the minibus. At the same time, the sensor real-time monitors the information of the actual position, speed, and lateral deviation of the vehicle, and feeds back this information to the intelligent driving controller, the lateral controller, and the longitudinal controller. Each controller adjusts the control strategy and parameters in real time according to the feedback information to form a closed-loop control.

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