Use environmental information to correct the predicted trajectory to keep the vehicle centered in the lane

Abstract

A method and system (105, 200) for centering a vehicle (100) in a lane. The system (105, 200) includes an electromagnetic radiation sensor (202, 205, 210), a motion sensor (115, 120, 130), a steering system (125, 127), and an electronic controller (110). The electronic controller (110) is configured to receive environmental information about an external environment of the vehicle (100) from the electromagnetic radiation sensor (202, 205, 210) and to receive a first motion of the vehicle (100) from the motion sensor (115, 120, 130). The electronic controller (110) is also configured to determine a predicted position of the vehicle (100) based on the first motion of the vehicle (100) and the environmental information, store the predicted position, compare the predicted position with an expected position of the vehicle (100) to generate and send a correction signal to the steering system (125, 127). The electronic controller (110) is also configured to determine a current position of the vehicle (100), compare the current position to a predicted position to generate a difference, and calibrate the motion sensors (115, 120, 130) based on the difference.

Description

Technical Field

[0001] Embodiments relate to automated steering for a vehicle. Background Art

[0002] Modern vehicles include various partially autonomous driving features, such as adaptive cruise control, collision avoidance systems, automatic parking, etc. Fully autonomous driving is a goal, but has not yet been achieved, at least not on a commercially viable scale that is feasible in the market. Summary of the invention

[0003] One goal of an automatically steering vehicle is to be able to accurately measure the dynamic characteristics of the vehicle in order to predict the future position of the vehicle. For lateral dynamic characteristics, sensors that can be used to predict vehicle motion include steering angle sensors, MEMS gyroscopes, and accelerometers. There are many reasons why motion sensors cannot always accurately measure the true motion of the vehicle. It is known that drift effects can cause MEMS-based inertial sensors to lose accuracy. Differences in the position of automotive parts due to turning, tire inflation, or road tilt may cause the yaw rate sensor to measure motion that is not parallel to the ground as lateral motion. Similarly, for steering angle-based sensing, when using sensors to predict future vehicle positions, there are some unmeasured additional external forces that can cause system errors. The embodiments described herein provide, among other things, an automatic steering system for a vehicle, wherein sensor signals (e.g., from a gyroscope, a steering angle sensor, or an accelerometer) are used as control signals for a closed-loop vehicle motion controller. In order to achieve robust control, the required or executed vehicle motion should be achieved. Environmental sensing can be used in conjunction with motion sensors to determine the true motion of the vehicle and correct system errors.

[0004] For driving within the range of linear vehicle dynamics, a single-track assumption is often sufficient to determine the correct steering angle to achieve the desired vehicle response. This assumption relies on being able to accurately sense the position of the vehicle's steering system. Because the position of the steering system is typically measured in only one place, the sensed steering angle may not be accurate in vehicles where the mechanical design of the steering system plays a role or where the configuration of the steering system can change dynamically (for example, in vehicles equipped with air suspension). One option is to model the mechanical properties of the steering system. However, modeling typically requires a significant software application expense for each mechanical design that the model is to accommodate, and may need to accommodate systems that change over time.

[0005] Embodiments provide, among other things, a system and method for centering a vehicle in a lane.

[0006] One embodiment provides a system for centering a vehicle in a lane. The system includes an electromagnetic radiation sensor, a motion sensor, a steering system, and an electronic controller. The electronic controller is configured to receive environmental information about an external environment of the vehicle from the electromagnetic radiation sensor and to receive a first motion of the vehicle from the motion sensor. The electronic controller is also configured to determine a predicted position of the vehicle based on the first motion of the vehicle and the environmental information, store the predicted position of the vehicle in a memory, and compare the predicted position of the vehicle with a desired position of the vehicle to generate a correction signal, and send the correction signal to the steering system of the vehicle. The electronic controller is also configured to determine a current position of the vehicle, compare the current position of the vehicle with the predicted position of the vehicle to generate a difference, and calibrate the motion sensor based on the difference.

[0007] Another embodiment provides a method for centering a vehicle in a lane. The method includes sensing environmental information about an environment outside the vehicle using an electromagnetic radiation sensor, and sensing a first movement of the vehicle using a motion sensor. The method also includes determining a predicted position of the vehicle based on the first movement of the vehicle and the environmental information using an electronic controller, storing the predicted position of the vehicle in a memory, comparing the predicted position of the vehicle with a desired position of the vehicle to generate a correction signal, and sending the correction signal to a steering system of the vehicle. The method also includes determining a current position of the vehicle, comparing the current position of the vehicle with the predicted position of the vehicle to generate a difference, and calibrating the motion sensor based on the difference.

[0008] Other aspects, features, and embodiments will become apparent by consideration of the detailed description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a block diagram of a vehicle equipped with a system for sensing and controlling vehicle motion.

[0010] Figure 2 is a block diagram of a vehicle equipped with a system for detecting the position of the vehicle relative to the surrounding environment.

[0011] Figure 3 is a block diagram of a vehicle navigating an exemplary surrounding environment over a period of time.

[0012] Figure 4 yes Figure 1 systems and Figure 2 Block diagram of the electronic controller of the system.

[0013] Figure 5 Based on Figure 2 Data calibration of the system Figure 1 The motion sensor and calibrate the vehicle's motion so that Figure 1 and Figure 2Flow chart of a method for using a system to predict a position as a desired position. DETAILED DESCRIPTION

[0014] Before any embodiments are explained in detail, it should be understood that the present disclosure is not intended to be limited in its application to the details of construction and the arrangement of components set forth in the following description or shown in the drawings. Embodiments are capable of other configurations and of being practiced or carried out in various ways.

[0015] Various embodiments may be implemented using a plurality of hardware and software-based devices and a plurality of different structural components. In addition, embodiments may include hardware, software, and electronic components or modules, which, for purposes of discussion, may be shown and described as if most components were implemented in hardware only. However, a person of ordinary skill in the art will recognize, based on a reading of this detailed specification, that in at least one embodiment, the electronic-based aspects of the present invention may be implemented with software (e.g., stored in a non-transitory computer-readable medium) that may be executed by one or more processors. For example, the "control unit" and "controller" described in the specification may include one or more electronic processors, one or more storage modules including non-transitory computer-readable media, one or more input / output interfaces, one or more application-specific integrated circuits (ASICs), and various connection structures (e.g., a system bus) connecting the various components.

[0016] Figure 1 and Figure 2 Two subsystems of a single system for centering vehicle 100 in a lane are shown. Figure 1 An example of a vehicle 100 is shown, which is equipped with a system 105 for sensing motion and controlling the position of the vehicle. Although the vehicle 100 is shown as a four-wheeled vehicle, various types and designs of vehicles can be covered. For example, the vehicle 100 can be a car, a motorcycle, a truck, a bus, a semi-tractor, etc. The vehicle 100 includes at least some autonomous functions, but a driver or operator may also be required to perform driving functions. In the example shown, the system 105 includes a plurality of hardware components, including an electronic controller 110, a speed sensor 115, a gyroscope 120, a steering control system 125, a steering angle sensor 127, and a three-dimensional (or 3-dimensional (3D)) accelerometer 130. The components of the system 105 can have various configurations, and various communication types and protocols can be used.

[0017] The electronic controller 110 may be communicatively connected to the speed sensor 115, the gyroscope 120, the steering control system 125, the steering angle sensor 127, and the three-dimensional accelerometer 130 via various wired or wireless connections. For example, in some embodiments, the electronic controller 110 is directly coupled to each of the above-listed components of the system 105 for sensing and controlling the vehicle's motion via dedicated lines. In other embodiments, the electronic controller 110 is communicatively coupled to one or more of these components via a shared communication link such as a vehicle communication bus (e.g., a controller area network (CAN) bus) or a wireless vehicle network.

[0018] The speed sensor 115 can be implemented, for example, using a wheel speed sensor that senses rotational speed. In other embodiments, other sensors, such as a transmission output speed sensor (TOSS) or other types of sensors, can be used alone or in combination with the wheel speed sensor to sense or determine the vehicle speed. In the illustrated embodiment, a single speed sensor 115 is associated with each wheel of the vehicle 100. In another example, the components of the system 105 may include a steering angle sensor 127, a steering actuator (e.g., an electric motor of an electric steering system), and other components that directly or indirectly (e.g., through differential braking) control the steering angle of the vehicle 100.

[0019] Each of the above-listed components of the system 105 may include dedicated processing circuitry including an electronic processor for receiving, processing, and transmitting data associated with the functionality of the respective component. For example, the three-dimensional accelerometer 115 may include an electronic processor that determines a parameter related to the directional motion of the vehicle. In this case, the three-dimensional accelerometer 115 transmits the parameter or a calculated value associated with the parameter to the electronic controller 110. Each component of the system 105 for sensing and controlling vehicle motion may communicate with the electronic controller 110 using a variety of communication protocols. Figure 1 The illustrated embodiment provides only one example of components and connections for sensing and controlling vehicle motion system 105. However, these components and connections may be configured in other ways than those shown and described herein.

[0020] Figure 2An example of a vehicle 100 is shown that is equipped with a system 200 for sensing environmental information about the environment outside the vehicle 100. In the example shown, the system 200 includes a plurality of hardware components, including an electronic controller 110, a radar sensor 202, a camera 205, a lidar sensor 210, a global positioning system 215, and a map 220. The map 220 may be a map of a geographic area around the vehicle 100, such as a map of an area having a radius of a predetermined size, such as 1 kilometer. The components of the system 200 may have various configurations and may use various communication types and protocols.

[0021] The electronic controller 110 may be communicatively connected to the radar sensor 202, the camera 205, the lidar sensor 210, the global positioning system 215, and the map 220 via various wired or wireless connections. For example, in some embodiments, the electronic controller 110 is directly coupled to each of the above-listed components of the system 200 for sensing environmental information about the environment outside the vehicle 100 via dedicated lines. In other embodiments, the electronic controller 110 is communicatively coupled to one or more of these components via a shared communication link such as a vehicle communication bus (e.g., a controller area network (CAN) bus) or a wireless vehicle network.

[0022] Each of the above-listed components of the system 200 for sensing environmental information about the environment outside the vehicle 100 may include dedicated processing circuitry including an electronic processor for receiving, processing, and transmitting data associated with the functionality of each component. For example, the camera 205 may include an electronic processor that determines an image for measuring the accuracy of the system 105 for sensing and controlling vehicle motion. In this case, the camera 205 transmits the image or a value associated with the image to the electronic controller 110. Each component of the system 200 for sensing environmental information about the environment outside the vehicle 100 may communicate with the electronic controller 110 using a variety of communication protocols. Figure 2 The illustrated embodiment provides only one example of the components and connections of the system 200 for sensing environmental information about the environment external to the vehicle 100. These components and connections may be configured in other ways than shown and described herein.

[0023] Radar sensor 202, camera 205, and lidar sensor 210 are electromagnetic radiation sensors. More than one of each electromagnetic radiation sensor may be provided, and they may be located at different locations inside or outside of vehicle 100. For example, camera 205 or a component thereof may be externally mounted to a portion of vehicle 100 (e.g., on an exterior rearview mirror or front end). Alternatively, camera 205 or a component thereof may be internally mounted within vehicle 100 (e.g., positioned on the dashboard or positioned by an interior rearview mirror). The electromagnetic radiation sensor is configured to be able to receive a signal indicating the distance and relative position of the vehicle from elements in the vehicle's surrounding environment 300 as vehicle 100 moves from one point to another.

[0024] Figure 3 is a block diagram of a vehicle 100 in an exemplary surrounding environment 300. The vehicle 100 is shown in a first position 302 (at a first moment in time) and in a second position 305 (at a second, later moment in time). Electromagnetic radiation sensors (e.g., sensors 202, 205, and 210) of the vehicle 100 detect the surrounding environment 300 of the vehicle 100 and elements of the environment ("environmental elements") including a dashed center line 310 ("lane marking"), a solid line 315 (another "lane marking"), a solid line 317, a building 320, and a road sign 325. The electronic controller 110 uses the elements that can be detected at the first position 302 and the second position 305 to calculate the position of the vehicle 100. For example, the building 320, the dashed center line 310, the solid line 315, and the solid line 317 are used twice to calculate the position of the vehicle because they can be detected at the first position 302 and the second position 305. The electronic controller 110 does not use environmental elements that cannot be detected at the first location 302 and the second location 305 to calculate the position of the vehicle 100. For example, the road sign 325 is not used to calculate the position of the vehicle because the road sign 325 cannot be detected at the first location 302 and the second location 305.

[0025] Figure 4 yes Figure 1 and Figure 2 1. The electronic controller 110 includes a plurality of electrical and electronic components that provide power, operational control, and protection for components and modules within the electronic controller 110. The electronic controller 110 includes, among other things, an electronic processor 405 (e.g., a programmable electronic microprocessor, microcontroller, or similar device), a memory 415 (e.g., a non-transitory, machine-readable memory), and an input / output interface 410. The electronic processor 405, in conjunction with the memory 415 and the input / output interface 410, is configured to enable implementation of, among other things, the methods described herein.

[0026] The electronic controller 110 may be implemented in a plurality of independent controllers (e.g., programmable electronic controllers), each of which is configured to perform a specific function or sub-function. In addition, the electronic controller 110 may include sub-modules including other electronic processors, memories, or application specific integrated circuits (ASICs) for handling input / output functions, signal processing, and application of the methods listed below. In other embodiments, the electronic controller 110 includes additional, fewer, or different components.

[0027] Figure 5 A method for centering a vehicle in a lane using a system 105 for sensing motion and controlling vehicle position and a system 200 for sensing environmental information about the external environment of the vehicle 100 is shown. Typically, the method performs a first task and a second task in parallel to center the vehicle 100 in the lane. In the method shown, an electronic processor 405 predicts a future position of the vehicle 100 relative to an element in the future surrounding environment of the vehicle (box 500). The predicted position is calculated based on the current motion of the vehicle (first motion) and the surrounding environmental elements. In some embodiments, the environmental elements used to determine the vehicle position include fixed infrastructure and road markings that appear at the predicted position of the vehicle and the current position of the vehicle. The predicted position is stored in the memory 415 of the electronic controller 110 as a position on a map 220 or as a set of variables describing the position relative to the environment (box 505).

[0028] The first task is to correct the motion of the vehicle so that the vehicle 100 moves to the desired position. In one example, the desired position is defined as the position where the vehicle 100 is centered in the lane. The electronic processor 405 uses inputs from the radar sensor 202, the camera 205, the lidar sensor 210, and the global positioning system 215 to determine the geographic location of the vehicle 100 on the map 220. The electronic processor 405 uses the map 220 and information from the system 105 to determine the desired position (box 515). The electronic processor 405 compares the predicted position of the vehicle 100 with the desired position of the vehicle 100 (box 520). If there is a difference between the desired position and the predicted position, a correction signal is generated by the electronic controller 110 and sent to a component that controls the steering angle of the vehicle 100 directly (e.g., by adjusting the angle of the axis of the front wheels relative to the front of the vehicle 100) or indirectly (e.g., by differential braking) (box 522). The correction signal causes an adjustment to the vehicle motion. The adjustment to the vehicle motion ensures that the desired position will be the same as the future position.

[0029] The second task is to determine whether and how to calibrate the system 105 for sensing motion and controlling the position of the vehicle. When the vehicle 100 should have reached the predicted position, the current position of the vehicle 100 is determined relative to the elements in the vehicle's current surroundings (box 525). The predicted position is retrieved from the memory 415 of the electronic controller. The predicted position of the vehicle 100 is then compared with the current position of the vehicle 100 (box 527). The difference between the predicted position and the current position indicates that the motion sensor is not calibrated correctly. Recalibrate the motion sensor based on the difference between the current position of the vehicle and the predicted position of the vehicle (box 530). If the predicted position is recalculated given the data from the recalibrated motion sensor, the predicted position and current position of the vehicle 100 will be the same. The second task is performed while the first task compares the second predicted position of the vehicle with the second expected position of the vehicle to generate a second correction signal and sends the second correction signal to the steering system of the vehicle 100.

[0030] Various features, advantages, and embodiments are set forth in the following claims.

Claims

1. A system for centering a vehicle in a lane, the system comprising: Electromagnetic radiation sensors; Motion sensor; Steering system; as well as An electronic controller configured to: receiving environmental information about the environment outside the vehicle from an electromagnetic radiation sensor, receiving a first motion of the vehicle from a motion sensor, At the first moment: determining a predicted position of the vehicle based on the first movement of the vehicle and the environmental information, storing the predicted position of the vehicle in memory, comparing the predicted position of the vehicle to the desired position of the vehicle to generate a correction signal, Sending a correction signal to the vehicle's steering system causes an adjustment to the vehicle's motion so that the predicted position becomes the desired position, determining a second time at which the vehicle should arrive at the predicted location, and At the second moment: Determine the vehicle's current location, Comparing the vehicle's current position to the vehicle's predicted position to generate a difference, The motion sensor is calibrated based on the difference.

2. The system according to claim 1, wherein: The desired position is the future position of the vehicle that centers the vehicle in the lane.

3. The system according to claim 1, wherein: The electromagnetic radiation sensor is at least one of the group consisting of a radar sensor, a camera, and a lidar sensor.

4. The system according to claim 1, wherein: The motion sensor is at least one of the group consisting of a steering angle sensor, a three-dimensional accelerometer, and a gyroscope.

5. The system according to claim 1, wherein: The adjustment includes adjusting a steering angle of the vehicle.

6. The system according to claim 1, wherein: The electronic controller is configured to determine the desired location using the map and the received environmental information.

7. The system according to claim 1, wherein: The predicted position can be stored as a location on a map or as a set of variables describing the location relative to the environment.

8. The system according to claim 1, wherein: Environmental elements sensed at the current location and the predicted location are used to determine the predicted location.

9. The system according to claim 1, wherein: Environmental elements sensed at the current location and the predicted location are used to determine the desired location.

10. A method for centering a vehicle in a lane, the method comprising: sensing environmental information about an environment outside the vehicle using an electromagnetic radiation sensor; sensing a first movement of the vehicle using a motion sensor; At the first moment: determining, using an electronic controller, a predicted position of the vehicle based on the first movement of the vehicle and the environmental information; storing the predicted position of the vehicle in a memory; comparing the predicted position of the vehicle to a desired position of the vehicle to generate a correction signal; sending a correction signal to a steering system of the vehicle, the correction signal causing an adjustment to the vehicle's motion so that the predicted position becomes the desired position; determining a second time at which the vehicle should arrive at the predicted location; and At the second moment: determining the current position of the vehicle; comparing the current position of the vehicle to the predicted position of the vehicle to generate a difference; The motion sensor is calibrated based on the difference.

11. The method according to claim 10, wherein: The vehicle's geographic location is based on information from the GPS and maps.

12. The method according to claim 10, wherein: The electromagnetic radiation sensor is at least one of the group consisting of a radar sensor, a camera, and a lidar sensor.

13. The method according to claim 10, wherein: The motion sensor is at least one of the group consisting of a steering angle sensor, a three-dimensional accelerometer, and a gyroscope.

14. The method according to claim 10, wherein: The desired position is the future position of the vehicle that centers the vehicle in the lane.

15. The method according to claim 10, wherein: Environmental elements sensed at the current location and the predicted location are used to determine the predicted location.

16. The method according to claim 10, wherein: Environmental elements sensed at the current location and the predicted location are used to determine the desired location.

17. The method according to claim 10, wherein: The adjustment includes adjusting a steering angle of the vehicle.

18. The method according to claim 10, wherein: The electronic controller is configured to determine the desired location using the map and the received environmental information.

19. The method according to claim 10, wherein: The steps of comparing the vehicle's current position with the vehicle's predicted position to generate a difference and calibrating the motion sensor based on the difference are performed in parallel with comparing the vehicle's second predicted position with the vehicle's second desired position to generate a second correction signal and sending the second correction signal to the vehicle's steering system.

20. The method according to claim 10, wherein: The predicted position can be stored as a location on a map or as a set of variables describing the location relative to the vehicle's external environment.

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