Vehicle braking system and method

Abstract

A vehicle braking system and method for braking a host vehicle traveling behind a second vehicle, the system and method comprising: acquiring a visual image of the second vehicle, and determining an actual deceleration of the second vehicle based on the visual image. Detecting non-visible light emitted by the second vehicle. Determining a commanded deceleration of the second vehicle based on the detected light. Generating a first signal indicating the actual deceleration. Generating a second signal indicating the commanded deceleration. In response to at least one of the first signal and the second signal, initiating braking of the host vehicle.

Description

Technical Field

[0001] The present invention relates generally to vehicle systems and, more particularly, to a vehicle assist system for controlling braking of a vehicle. Background Art

[0002] Current driver assistance systems (ADAS – Advanced Driver Assistance Systems) provide a range of monitoring functions in vehicles. In particular, ADAS can monitor the environment around the vehicle and notify the driver of the vehicle or other systems of the vehicle of conditions in that environment. To do this, ADAS can capture images of the surrounding environment and digitally process these images to extract information. This information is used to warn the driver of road obstacles along the driving path. Common ADAS include automatic emergency braking (helps prevent rear-end collisions) and lane detection (helps keep the vehicle within the commanded driving lane). Summary of the invention

[0003] A method for braking a host vehicle traveling behind a second vehicle, the method comprising: acquiring a visual image of the second vehicle and determining an actual deceleration of the second vehicle based on the visual image; detecting non-visible light emitted by the second vehicle; determining a commanded deceleration of the second vehicle based on the detected light; generating a first signal indicating the actual deceleration; generating a second signal indicating the commanded deceleration; and initiating braking of the host vehicle in response to at least one of the first signal and the second signal.

[0004] In another aspect, a system for controlling braking of a host vehicle traveling behind a second vehicle on a road includes a camera assembly disposed on the host vehicle, the camera assembly being used to obtain a visual image of the second vehicle. The camera assembly determines an actual deceleration of the second vehicle based on the visual image. The camera assembly detects non-visible light emitted by the second vehicle and determines a commanded deceleration of the second vehicle based on the detected light. The camera assembly generates a first signal indicating the actual deceleration and a second signal indicating the commanded deceleration. A controller receives the first signal and the second signal, and initiates braking of the host vehicle in response to at least one of the first signal and the second signal.

[0005] Other objects and advantages of the present invention and a more complete understanding of the present invention will be appreciated from the following detailed description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a top view of the vehicle with the assistance system according to the present invention.

[0007] Figure 2 yes Figure 1 Schematic representation of the assistance system.

[0008] Figure 3A It is a schematic representation of a host vehicle traveling on a road and detecting a second vehicle in front of the host vehicle.

[0009] Figure 3B yes Figure 3A A rear view of a second vehicle.

[0010] Figure 4 is a schematic representation of a portion of a second vehicle. DETAILED DESCRIPTION

[0011] The present invention relates generally to vehicle systems, and more particularly to a vehicle assist system for controlling a braking operation of a vehicle. Figure 1 A host vehicle 20 is shown with an example assistance system 30 according to the present invention.

[0012] The present vehicle 20 extends from a front end 22 to a rear end 24. The vehicle 20 includes at least one camera assembly 40 that includes a camera 44 and a software module 46 for processing data collected by the camera. It should be understood that the software module 46 can be integrated with the camera 44 or located at a different location from the camera (not shown). The camera 44 has a field of view 42 extending from the vehicle 20. As shown, the camera assembly 40 is connected to the front end 22 and has a field of view 42 extending in front of the vehicle 20. Alternatively or additionally, the camera assembly 40 can be connected to the rear end 24 of the vehicle 20 so that the field of view 42 extends to the rear of the vehicle (not shown).

[0013] Camera assembly 40 is configured to both acquire a visual image and detect non-visible light (eg, infrared (IR) light or ultraviolet light) within field of view 42. Non-visible light may be detected within the visual image or independently of the visual image.

[0014] refer to Figure 2 , the controller 50 is connected to the camera assembly 40 and receives signals from the camera assembly. More specifically, the camera assembly 40 sends one or more first signals S1 to the controller 50 based on the visual image acquired in the field of view 42. The camera assembly 40 sends one or more second signals S2 to the controller 50 based on the non-visible light detected in the field of view 42. To this end, the software module 46 can be integrated into the controller 50 (not shown).

[0015] The controller 50 is also electrically or wirelessly connected to an actuator 52 associated with a vehicle brake 54. The controller 50 can send a control signal to the brake actuator 52 to actuate the brake 54 and thereby reduce the speed of the vehicle 20, i.e., control the brake operation of the vehicle. The brake 54 can also be manually operated by the operator of the host vehicle 20 by depressing the brake pedal 56. Although the brake pedal 56 is shown as being directly connected to the brake 54, it should be understood that the brake pedal can alternatively be connected to the actuator 52 and / or the controller 50 (not shown) for operating the brake.

[0016] refer to Figure 3A , the vehicle 20 is configured to travel along a road 70. The road 70 has a vehicle travel direction indicated by arrow T. The road 70 includes a series of lanes 72 and 74 separated by a dashed dividing line 76. Fewer lanes or additional lanes and dividing lines are contemplated but are not shown. The road 70 is demarcated from the surrounding non-road area 80 by a boundary line 82 on the left side (relative to the travel direction T) and a boundary line 84 on the right side.

[0017] When the vehicle 20 is traveling along the road 70, the camera 44 detects objects in front of the vehicle 20 in the field of view 42. In one example, the camera 44 detects a second vehicle 100 traveling on the road 70, in front of the vehicle and in the same lane 74. The second vehicle 100 extends from a front end 102 to a rear end 104. Brake lights 106L, 106R are provided on the rear end 104 (see also Figure 3B ). One or more light sources are disposed on the rear end 104 adjacent to the brake lights 106L, 106R. As shown, a pair of light sources 108L, 108R are disposed on the rear end 104 and are associated with each brake light 106L, 106R. In another example, a single light source (not shown) may be disposed between the brake lights 106L and 106R. The light sources 108L, 108R may be light emitting diodes (LEDs) that emit non-visible light (e.g., infrared light or ultraviolet light). The light sources 108L, 108R may also emit visible light, such as light of approximately 380 to 740 nm.

[0018] Controller 120( Figure 4 ) is connected to the brake lights 106L, 106R and the light sources 108L, 108R and controls the operation of these brake lights and light sources. The operator of the second vehicle 100 can depress the brake pedal 122 to actuate the brake 126, thereby reducing the speed of the vehicle 100, that is, controlling the brake operation of the vehicle. The controller 120 is also electrically or wirelessly connected to the actuator 124 associated with the brake 126.

[0019] The controller 120 may send a control signal to the brake actuator 124 to actuate the brake 126 in response to, for example, an operator command, a sensed vehicle collision, during adaptive cruise control, etc. Thus, the brake 126 may be controlled by the operator or the controller 120. In either case, when the brake 126 is operated, the controller 120 sends one or more signals S3 to the brake lights 106L, 106R. In response, the brake lights 106L, 106R illuminate to visually notify the vehicle behind the second vehicle 100 (e.g., vehicle 20) of the expected deceleration of the vehicle 100.

[0020] When the brake 126 is operated, for example, by depressing the brake pedal 122 or autonomously by the controller 120, the controller monitors the position of the brake pedal and outputs one or more signals S4 indicating the braking of the vehicle 100 commanded by the operator. To this end, the signal S4 indicates the braking intensity or braking curve commanded by the operator. When the brake 126 is operated using the actuator 124, a signal S4 is also output, which reflects the braking intensity or braking curve commanded by the controller 120.

[0021] Signal S4 may also be output when the controller 120 activates an anti-lock braking system (ABS) 128. Such activation may occur, for example, when the controller 120 determines that road conditions and / or environmental conditions may cause or are causing traction issues between the second vehicle 100 and the road 70. Thus, in this case, signal S4 indicates that activation of the ABS 128 has been commanded. The ABS 128 may be activated in addition to or in lieu of applying the brakes 126. That is, in all three cases, signal S4 represents a commanded deceleration of the vehicle 100.

[0022] In each of the above scenarios, signal S4 causes light sources 108L, 108R to emit non-visible light in a specific sequence, pattern, intensity, etc. to indicate the commanded deceleration. Figure 4 In the illustrated configuration, the controller 120 quantifies the commanded brake operation into braking intention data 130. This may include, for example, force, velocity and acceleration applied to the brake 126, activation of the ABS 128, etc. The controller 120 then encodes 132 the braking intention data 130 into, for example, a digital signal using a lookup table or the like. The encoded signal is then used to modulate a carrier frequency 134 in an exclusive OR (XOR) operation 140. In one example, pulse width modulation is used to combine the encoded signal with the carrier frequency 134. This modulated signal is the signal S4 sent to and output by the light source 108L, 108R.

[0023] Return to reference Figures 2 to 3AIn operation, the system 30 on the host vehicle 20 is configured to monitor both the actual deceleration and the commanded deceleration of the vehicle 100 based on the signals S3, S4. To this end, the camera 44 acquires visual images of the vehicle 100, including images of the brake lights 106L, 106R within the field of view 42. These images are sent to and processed by the software module 46 to determine the actual deceleration of the vehicle 100. This can be achieved, for example, by comparing the size and / or intensity of the brake lights 106L, 106R in different images, or by monitoring the distance between the vehicle 20 and the vehicle 100 over time. In either case, the actual deceleration data is sent to the controller 50 as the signal S1.

[0024] At the same time, the camera 44 detects the non-visible light emitted by the light sources 108L, 108R. Data indicating the detected non-visible light is sent to the software module 46 and processed by the software module. The software module 46 decodes the modulated signal output by the light sources 108L, 108R and captured by the camera 44. The decoded signal is used to determine the commanded deceleration or expected deceleration of the vehicle 100. The commanded deceleration data is sent to the controller 50 as a signal S2. The controller 50 on the host vehicle 20 continuously receives the first signal S1 and the second signal S2 from the camera 44, thereby continuously detecting and monitoring any actual deceleration and commanded deceleration of the second vehicle 100.

[0025] The controller 50 determines whether to initiate a braking operation in the host vehicle 20 in response to receiving the signals S1, S2. For example, the controller 50 may compare the first signal S1 with the second signal S2 and determine whether the second vehicle 100 is slipping. Slipping may be caused by tire conditions, severity of commanded deceleration, wet roads, etc. When the first signal S1 indicates that the actual deceleration is less than the commanded deceleration reflected in the second signal S2 by a predetermined amount, the controller 50 may actuate the brake actuator 52 to initiate braking, apply the brake 54 with a desired traction control curve, etc. / or apply a traction control curve.

[0026] In one example, the predetermined amount is sufficient to account for tolerances in the devices used to generate the signals, such as the controllers 50, 120 and the camera assembly 40. In other words, the difference between the signal S1 and the signal S2 should be large enough so as not to falsely indicate that the second vehicle 100 is slipping when in fact no slip is occurring.

[0027] On the other hand, when the signals S1, S2 indicate that the difference between the actual deceleration and the commanded deceleration of the second vehicle 100 is or is within the predetermined amount, the controller 50 determines that no slip has occurred. Although the controller 50 may not subsequently initiate braking based on such a result of the comparison of the signals S3, S4, it should be understood that the controller may still initiate braking based on determining that the second vehicle 100 is braking.

[0028] As noted, signal S4 may also indicate that second vehicle 100 has activated its ABS 128. When this occurs, signal S2 received by controller 50 indicates activation of ABS 128. In response, controller 50 actuates brake actuator 52 to apply brake 54 in the desired manner.

[0029] It should be understood that when the controller 50 determines that the second vehicle 100 is skidding, the controller may initiate alternative or additional safety measures. For example, the controller 50 may initiate airbag actuation and / or may initiate steering control to perform evasive maneuvers to avoid / mitigate a collision with the second vehicle if a collision situation is detected (neither shown).

[0030] Based on the above, it is clear that the use of non-visible light for inter-vehicle data transmission is advantageous because such light is invisible to humans / other drivers and therefore is not distracting. In addition, most driving light sources (e.g., parking lights, street lights, etc.) do not include non-visible light. Therefore, the camera assembly shown and described herein can determine with a high probability that the non-visible light captured in the image is from the light source of another vehicle. In other words, the non-visible light is for braking intention data and does not interfere with traditional light sources, and therefore provides a reliable source of information for the system. With this in mind, the ability of the system shown and described herein to acquire and process data not only related to the actual braking of another vehicle but also related to the expected / commanded braking enables the vehicle to respond more accurately to the event that the other vehicle slips.

[0031] What has been described above are examples of the present invention. Of course, it is not possible to describe every conceivable combination of components or methods for the purpose of describing the present invention, but one of ordinary skill in the art will recognize that many other combinations and permutations of the present invention are possible. Therefore, the present invention is intended to cover all such changes, modifications and variations that fall within the spirit and scope of the appended claims.

Claims

1. A method for braking a vehicle traveling behind a second vehicle, the method comprising: acquiring a visual image of the second vehicle and determining an actual deceleration of the second vehicle based on the visual image; detecting non-visible light emitted by the second vehicle and determining a commanded deceleration of the second vehicle based on the detected light; generating a first signal indicative of the actual deceleration and a second signal indicative of the commanded deceleration; as well as In response to at least one of the first signal and the second signal, braking of the host vehicle is initiated, wherein: When the actual deceleration is less than the commanded deceleration by at least a predetermined amount, a controller initiates braking.

2. The method of claim 1, wherein: Detecting non-visible light emitted by the second vehicle includes detecting infrared light.

3. The method of claim 1, wherein: The first signal includes data indicative of an actual braking force applied to brakes of the second vehicle.

4. The method of claim 1, wherein: The second signal includes data indicative of an active anti-lock braking system.

5. The method of claim 1, wherein: The second signal is generated in response to decoding a modulated signal emitted by the non-visible light.

6. The method of claim 5, wherein: The modulation signal is a pulse width modulation signal.

7. The method of claim 1, wherein: The controller initiates braking when the second signal indicates that the second vehicle has an ABS system activated.

8. A system for braking a host vehicle travelling behind a second vehicle on a road, the system comprising: a camera assembly disposed on the host vehicle, the camera assembly being configured to acquire a visual image of the second vehicle and determine an actual deceleration of the second vehicle based on the visual image, the camera assembly detecting non-visible light emitted by the second vehicle and determining a commanded deceleration of the second vehicle based on the detected light, the camera assembly generating a first signal indicating the actual deceleration and a second signal indicating the commanded deceleration; as well as A controller is configured to receive the first signal and the second signal and, in response to at least one of the first signal and the second signal, initiate braking of the host vehicle, wherein the controller initiates braking when the actual deceleration is less than the commanded deceleration by at least a predetermined amount.

9. The system of claim 8, wherein: Detecting non-visible light emitted by the second vehicle includes detecting infrared light.

10. The system of claim 8, wherein: The first signal includes data indicative of an actual braking force applied to brakes of the second vehicle.

11. The system of claim 8, wherein: The second signal includes data indicative of an active anti-lock braking system.

12. The system of claim 8, wherein: The second signal is generated in response to decoding a modulated signal emitted by the non-visible light.

13. The system of claim 12, wherein: The modulation signal is a pulse width modulation signal.

14. The system of claim 8, wherein: The controller initiates braking when the second signal indicates that the second vehicle has an ABS system activated.

Images