Trailer rear camera sensing mechanism and method

Abstract

A system for detecting motion of a trailer having a rear facing camera and linked to a towing vehicle. The system includes taking a first image and a second image with the camera and comparing the images. A first amount of trailer motion between the second image and the first image is determined. The system can also take additional images and determine a second amount of trailer motion that occurs between the additional images. The first and second amounts of trailer motion are tracked to determine an amount of trailer sway. The determined amount of trailer sway can be compared to a maximum allowed sway and if the motion is greater than the maximum allowed sway, the sway of the trailer is mitigated with the towing vehicle.

Description

Technical Field

[0001] This disclosure relates to methods, mechanisms, and systems for determining the motion of a trailer attached to a towing vehicle. Summary of the Invention

[0002] A method and system are provided for detecting the motion of a trailer linked to a towing vehicle, the trailer having a rear-facing camera. Parts or components of the system operate by capturing a first image using the camera and capturing a second image using the camera. The second image and the first image can be compared, and a first amount of trailer motion between the second and first images can be determined.

[0003] The system can also capture a third and a fourth image using a camera and compare the fourth image with the third image. This comparison can be used to determine a second amount of trailer motion that occurs between the fourth and third images. By tracking the first and second amounts of trailer motion, the system determines the amount of trailer sway.

[0004] The system can compare the determined trailer sway with the maximum permissible sway, and if the movement exceeds the maximum permissible sway, it can use the towing vehicle to mitigate the trailer sway. Mitigating trailer sway may involve the towing vehicle performing one or more of the following: differential braking, active rear steering, active forward steering, or braking together with the trailer.

[0005] The system can use one or both of the towing vehicle's front camera or sensors to determine whether the trailer's movement is in response to the towing vehicle's movement. If the trailer's movement is in response to the towing vehicle's movement, swaying is not mitigated, even if the trailer's movement exceeds the maximum permissible sway.

[0006] In some configurations, the method and system may determine the position of one or more lane markings in a first image and determine or estimate the position of a trailer relative to one or more lane markings in the first image. Similarly, the method and system may determine the position of one or more lane markings in a second image and determine or estimate the position of a trailer relative to one or more lane markings in the second image. These positions can be used to determine a second amount of trailer movement relative to lane markings that occurs between the second and first images.

[0007] In some configurations, the method and system can determine the lateral and forward velocities of the camera from the captured images. The determined lateral and forward velocities of the camera can be used to determine or estimate the trailer length.

[0008] The present invention may also include the following solutions.

[0009] 1. A method for detecting the motion of a trailer having a rear-facing camera and linked to a towing vehicle, comprising:

[0010] The first image is captured using the camera;

[0011] The second image is captured using the camera;

[0012] Compare the second image with the first image; and

[0013] Determine a first amount of trailer movement that occurs between the second image and the first image.

[0014] 2. The method according to Scheme 1 further includes:

[0015] Use the camera to capture a third image;

[0016] The fourth image is captured using the camera;

[0017] Compare the fourth image with the third image;

[0018] Determine a second amount of trailer movement occurring between the fourth and third images; and

[0019] The first and second quantities of trailer movement are tracked to determine trailer sway.

[0020] 3. The method according to Scheme 2 further includes:

[0021] Compare the determined trailer sway with the maximum permissible sway; and

[0022] If the determined trailer sway exceeds the maximum permissible sway, the towing vehicle is used to mitigate the determined trailer sway.

[0023] 4. The method according to Scheme 3, wherein mitigating the determined trailer sway includes: the tractor performing one or more of differential braking, active rear steering, or active forward steering.

[0024] 5. The method according to Scheme 4 further includes:

[0025] The first or second amount of trailer movement is determined using one or more of the front camera or sensors of the towing vehicle; and

[0026] If the first or second amount of trailer movement is in response to the movement of the towing vehicle, then swaying is not mitigated, even if the trailer movement exceeds the maximum permissible sway.

[0027] 6. The method according to Scheme 1 further includes:

[0028] Determine the location of one or more lane markings in the first image; and

[0029] Determine the position of the trailer relative to one or more lane markings in the first image.

[0030] 7. The method according to Scheme 6 further includes:

[0031] Determine the location of one or more lane markings in the second image; and

[0032] Determine the position of the trailer relative to one or more lane markings in the second image; and

[0033] Determine a second amount of trailer movement relative to the one or more lane markings occurring between the second image and the first image.

[0034] 8. The method according to Scheme 2, wherein the first amount of trailer movement is a first lateral amount of trailer movement, and the method further includes:

[0035] Determine a first longitudinal amount of trailer movement that occurs between the second image and the first image.

[0036] 9. The method according to claim 8, wherein the second amount of trailer movement is a second lateral amount of trailer movement, and the method further comprises:

[0037] Determine the second longitudinal amount of trailer movement that occurs between the fourth and third images.

[0038] 10. The method according to Scheme 2 further includes:

[0039] The lateral velocity of the camera is determined from one or more of the first image, the second image, the third image, and the fourth image;

[0040] The forward velocity of the camera is determined from one or more of the first image, the second image, the third image, and the fourth image; and

[0041] The trailer length is determined based on the determined lateral speed and determined forward speed of the camera.

[0042] 11. The method according to Scheme 3, wherein mitigating the determined trailer sway further includes: uniform braking of the trailer or differential braking of the trailer.

[0043] 12. A non-transitory computer-readable medium including content configured to cause a computing system to perform a method for detecting motion of a trailer having a rear-facing camera, the method comprising:

[0044] The first image is captured using the rear-facing camera;

[0045] The second image is captured using the rear-facing camera;

[0046] Compare the second image with the first image; and

[0047] Determine a first amount of trailer movement that occurs between the second image and the first image.

[0048] 13. The non-transitory computer-readable medium according to claim 12 further includes:

[0049] The third image is captured using the rear-facing camera;

[0050] The fourth image is captured using the rear-facing camera;

[0051] Compare the fourth image with the third image;

[0052] Determine the second amount of trailer motion that occurs between the fourth and third images; and

[0053] The first and second quantities of trailer movement are tracked to determine trailer sway.

[0054] 14. The non-transitory computer-readable medium according to claim 13 further includes:

[0055] Compare the determined trailer sway with the maximum permissible sway; and

[0056] If the motion exceeds the maximum permissible sway, the sway of the trailer is mitigated by using a towing vehicle attached to the trailer.

[0057] 15. The non-transitory computer-readable medium according to claim 14, wherein mitigating trailer sway includes: the tractor performing one or more of differential braking, active rear steering, or active forward steering.

[0058] 16. The non-transitory computer-readable medium according to claim 12 further includes:

[0059] Determine the location of one or more lane markings in the first image; and

[0060] Determine the position of the trailer relative to one or more lane markings in the first image.

[0061] 17. The non-transitory computer-readable medium according to claim 16 further includes:

[0062] Determine the location of one or more lane markings in the second image; and

[0063] Determine the position of the trailer relative to one or more lane markings in the second image; and

[0064] Determine a second amount of trailer movement relative to the lane markings that occurs between the second image and the first image.

[0065] 18. The non-transitory computer-readable medium according to claim 12 further includes:

[0066] The lateral velocity of the rear-facing camera is determined from one or more of the first image and the second image;

[0067] Determine the forward velocity of the rearward camera from one or more of the first image and the second image; and

[0068] The trailer length is determined based on the determined lateral velocity and determined forward velocity of the rear camera.

[0069] The foregoing features and advantages, as well as other features and advantages, of this disclosure will become apparent from the following detailed description of the best mode for carrying out this disclosure, taken in conjunction with the accompanying drawings. Attached Figure Description

[0070] Figure 1 This is a diagram of a towing vehicle that pulls a trailer.

[0071] Figure 2 This is a schematic flowchart illustrating the logic used to determine and mitigate trailer sway.

[0072] Figure 3 This is a schematic diagram used to illustrate the tracking and mitigation of trailer swaying. Detailed Implementation

[0073] Referring to the accompanying drawings, the same reference numerals denote similar parts wherever possible. All descriptions in the drawings are also referenced to all other drawings. Figure 1 A towing vehicle 10, which can be, for example, but not limited to, a conventional vehicle, an electric vehicle, or a hybrid electric vehicle, is schematically shown. The towing vehicle 10 and its system are capable of detecting the movement of a trailer 12, which is connected to the towing vehicle 10 via a hook structure or simply via a hook 14.

[0074] The control system or controller 16 operatively communicates with at least the necessary components of the tractor vehicle 10 and trailer 12 to perform the methods, algorithms, and health assessments described herein. The controller 16 includes, for example, but not limited to, a non-general-purpose electronic control device having a pre-programmed digital computer or processor, memory, storage device, or non-transitory computer-readable medium for storing data such as control logic, instructions, lookup tables, etc., and multiple input / output peripherals, ports, or communication protocols. The controller 16 is configured to execute or implement all the control logic or instructions described herein.

[0075] Furthermore, controller 16 may include or communicate with multiple sensors, including but not limited to those configured to sense or estimate the ambient temperature outside the tractor vehicle 10, various coolant temperatures within the tractor vehicle 10, and other sensing capabilities. Controller 16 may be dedicated to a specific aspect of the tractor vehicle 10 described herein, or controller 16 may be part of a larger control system that manages many functions of the tractor vehicle 10.

[0076] The accompanying drawings and figures presented herein are illustrative, not to scale, and are provided for descriptive and support purposes only. Therefore, any specific or relative dimensions or alignments shown in the drawings should not be construed as limiting. While this disclosure may be illustrative with respect to a particular application or industry, those skilled in the art will recognize its broader applicability. Those skilled in the art will recognize that terms such as “above,” “below,” “up,” and “down” are used to describe the drawings and do not imply a limitation on the scope of this disclosure as defined by the appended claims. Any numerical designations such as “first” or “second” are merely illustrative and are not intended to limit the scope of this disclosure in any way. Any use of the term “or,” whether in the specification or the claims, includes any specific element referenced and any combination of referenced elements, unless otherwise expressly stated.

[0077] A feature shown in one figure may be combined with, replaced by, or modified by a feature shown in any figure. Unless otherwise stated, no feature, element, or limitation is mutually exclusive with any other feature, element, or limitation. Furthermore, no feature, element, or limitation is absolutely necessary for operation. Any particular configuration shown in the figures is merely illustrative and does not limit the claims or specification.

[0078] All numerical values ​​of parameters (e.g., quantities or conditions) in this application (including the appended claims) should in all cases be understood to be modified by the term "about / approximately," regardless of whether the term actually precedes the numerical value. "About" indicates that the numerical value allows for some slight imprecision (a value that is somewhat close to the exact value; approximately or reasonably close to the value; almost). If the imprecision provided by "about" cannot be understood in this ordinary sense in the art, then "about" as used herein at least indicates a difference that may arise from common methods of measuring and using these parameters. Furthermore, the disclosure of ranges includes the disclosure of all values ​​and ranges further subdivided throughout the range. Each value within the range and the endpoints of the range are disclosed herein as separate embodiments.

[0079] When used, the term "substantially / approximately" refers to an ideal, perfect, or complete relationship, where manufacturing reality prevents absolute perfection. Therefore, "substantially" indicates a typical difference from perfection. For example, if height A is substantially equal to height B, it might be preferable that the two heights are 100.0% equal, but manufacturing reality may result in distances differing from this perfection. A skilled technician will recognize acceptable amounts of difference. For example, but not limited to, coverage, area, or distance can generally be within 10% of being completely identical to substantially equivalents. Similarly, relative alignments, such as parallel or perpendicular, can generally be considered within 5%.

[0080] The tractor vehicle 10 may have a communication system capable of sharing information determined by, for example, the controller 16 or other components of the tractor vehicle 10 with locations outside the tractor vehicle 10. For example, but not limited to, the communication system may include cellular or Wi-Fi technologies that allow signals to be transmitted to a centralized location such as a cloud or communication network. It is conceivable that the methods and mechanisms described herein may occur on the tractor vehicle 10, in a cloud system, a combination of both, or via other computing systems, such that the controller 16 or its functions can be performed outside the tractor vehicle 10.

[0081] Trailer 12 has a rear-facing camera 20 mounted thereon, typically mounted at the end of trailer 12 relative to the normal direction of movement of towing vehicle 10. Camera 32 is linked to or communicates with towing vehicle 10 and related systems. Camera 20 is configured to capture a series of images and compare these images, for example using controller 16 or other systems of towing vehicle 10, such that the images are used to determine at least a first and a second amount of movement of trailer 12 occurring between images. Furthermore, camera 20 can capture video, such that the images can be frames of video.

[0082] One or more consecutive images are compared to determine motion and trailer sway. By comparing at least two images, the system can determine the relative amount of motion of camera 20 between at least two images based on the positions of portions of the compared images. As a very basic example, and without limitation, camera 20 can capture the positions of trees or other vehicles in consecutive images, and determine the amount of motion of camera 20 and trailer 12 between images by comparing the positions of trees or other vehicles in the images.

[0083] The determined motion of trailer 12 can be a lateral left-right movement or a longitudinal up-down movement. Therefore, the system can determine the lateral motion, longitudinal motion, or both of these of trailer 12.

[0084] By comparing multiple images from camera 20 with multiple instances of determined motion of trailer 12, such as a first motion and a second motion, the system can determine trailer sway, which is trailer sway when trailer 12 moves laterally or sways behind towing vehicle 10. Trailer sway can be determined relative to a previous position or relative to lane markings on the road over which trailer 12 and towing vehicle 10 are moving. The position of trailer 12 can also be plotted or tracked over time, for example using a signal sent to controller 16, and sway can be determined based on a comparison of that signal or its peak value. Regardless of the measurement or marking type, excessive trailer sway may require mitigation by towing vehicle 10, trailer 12, or both.

[0085] The method for determining the motion of trailer 12 may further include: determining the position of one or more lane markings in a captured image from camera 20. The lane markings can then be used to determine the amount of motion or trailer sway that the trailer 12 has made relative to the lane markings in the captured image. Note that the comparison of one or more images may or may not be used with lane markings, such that the method can simply compare images to determine motion, compare the positions of lane markings to determine motion, or both.

[0086] In addition to determining the motion or sway of trailer 12, the system described herein can also compare the determined trailer sway with the maximum permissible sway. If the motion exceeds the maximum permissible sway, the system can mitigate the sway of trailer 12 using the towing vehicle 10 or the trailer 12 itself.

[0087] Examples of mitigating the swaying of trailer 12 include, but are not limited to, the towing vehicle 10 performing one or more of differential braking, active rear steering, and / or active front steering. Differential braking typically refers to braking the right or left side of the towing vehicle 10. Generally, mitigation techniques are used to counteract the torque generated by the swaying trailer 12 by utilizing the opposing torque of the towing vehicle 10. Figure 3The diagram schematically illustrates the implementation of one or more mitigation techniques.

[0088] Note that in some configurations, trailer 12 may be able to mitigate its own sway. For example, but not limited to, trailer 12 may be configured to perform trailer differential braking on its left or right side to minimize sway after the system has determined excessive sway using camera 20. Additionally, trailer 12 may perform uniform braking to mitigate sway. Where the system also tracks the longitudinal movement of trailer 12, towing vehicle 10 may employ other, and possibly different, mitigation strategies, as those skilled in the art will recognize.

[0089] like Figure 1 As illustrated, the methods and systems described herein can also be used to estimate the length of trailer 12 when the controller 16 or the towing vehicle 10 is unknown. Trailer length 26 (L) C The distance from hook 14 is the trailer length, which can be determined based on the motion of camera 20 as determined by the system described herein.

[0090] The system can determine the lateral velocity 28 (V) of camera 20 from one or more captured images. cy This can also be referred to as the y-velocity of camera 20. Additionally, the system can determine the forward velocity 30 (V) of camera 20 from one or more captured images. cx This can also be referred to as the x-speed of camera 20. These speeds, along with other data points and / or determination results, can be used to determine the trailer length 26 of trailer 12.

[0091] like Figure 1 As shown, there are multiple other data points or calculations that can be obtained relative to the tractor 10, trailer 12, or both. Wheelbase length 32 (L) tr ) is the distance from the axle of hook 14 to trailer 12. The rear axle speed of the tractor vehicle 10 is 34 (V). v The speed can be determined by wheel speed sensors, inertial measurement units (IMUs), or other mechanisms known to those skilled in the art.

[0092] Hook distance 36 (L) h L is the distance from the rear axle of the tractor 10 to the connection between the hook 14 and the tractor 10. In many cases, L h and L tr The hook articulation angle 38(θ) will be known. It can be determined or estimated, for example, but not limited to, by: direct measurement, a rear-view camera on the towing vehicle 10, parking sensors, or a kinematic model. The trailer yaw rate is 40( ) and yaw rate of tractor vehicle 42 ( This can be determined by wheel speed sensors, IMUs, or other mechanisms.

[0093] Equations (1), (2) and (3) show the above-mentioned kinematic relationship with respect to the tractor 10 and the trailer 12.

[0094] (1)

[0095] (2)

[0096] (3)

[0097] By combining equations (1) - (3), we derive equation (4).

[0098] (4)

[0099] When the kinematic model of equation (3) is valid, the trailer length is 26 (L) C The value can be determined by using equation (4) with an estimation algorithm, which includes, but is not limited to, least squares, maximum likelihood, or gradient, typically when the traction vehicle 10 system speed is low, such as, but not limited to, less than 30 km / h.

[0100] Now for reference Figure 2 Referring to other accompanying drawings, a flowchart 50 is shown schematically illustrating some of the logic involved in determining the sway of trailer 12 and, in a preferred embodiment, mitigating trailer sway. In many configurations, the towing vehicle 10 includes additional components that contribute to the systems and methods described herein. For example, but not limited to, the towing vehicle 10 may include a front camera 52 and multiple motion sensors or vehicle sensors 54, including but not limited to IMUs, accelerometers, and / or gyroscopes.

[0101] The system may use either or both of the front camera 52 of the towing vehicle 10 or the vehicle sensor 54 to determine whether the movement of the trailer 12 is in response to the movement of the towing vehicle 10. For example, but not limited to, the towing vehicle 10 may intentionally change lanes or avoid road hazards, which would otherwise cause the system to consider the trailer 12 to be swaying outside its lane markings or swaying beyond the maximum permissible amount. However, if the movement of the trailer 12 is in response to the movement of the towing vehicle 10, the system may not mitigate the swaying, even if the movement of the trailer 12 would exceed the maximum permissible sway.

[0102] like Figure 2 As schematically illustrated, current frame block 62 represents the most recent image captured by camera 20, while previous frame block 64 represents the second most recent image captured by camera 20. Note that the system and method described herein can incorporate additional frames. Motion detection block 66 compares the current frame with the previous frame to determine the amount of motion of trailer 12.

[0103] Lane marker detection block 68 locates lane markers in one or more of the current and previous frames. Sway detection block 70 uses either or both of motion detection block 66 and lane marker block 68 to determine the amount of trailer sway occurring in trailer 12. Figure 3 As illustrated and described herein, when the trailer sway exceeds the maximum permissible sway, the trailer lane keeping block 72 can implement mitigation measures to reduce the sway. Note that trailer lane keeping can be achieved even when the trailer sway does not exceed the maximum permissible sway, because even when trailer 12 is not swaying, trailer 12 may drift out of the lane as measured by lane markings. The trailer length estimation block 74 uses equations (1)-(4) to estimate the length of trailer 12.

[0104] Camera 20 is typically an additional feature of trailer 12, although it can be included in the towing vehicle 10. Therefore, when a user may mount camera 20 at the rear of trailer 12, camera 20 may not be mounted at the precise center of trailer 12.

[0105] To account for the offset of camera 20, the system can use calibration input, or it can estimate that camera 20 is close enough to the center of trailer 12. Note that determining the magnitude of the sway between images is generally not affected by a slightly off-center camera 20. Alternatively, the system may include mechanisms or methods to determine the placement of camera 20 relative to the center of trailer 12 based on, for example, but not limited to, the location of lane markings or other methods known to those skilled in the art.

[0106] Now for reference Figure 3 Referring to other accompanying figures, a schematic motion or sway curve 110 is shown, including an x-axis 112 showing the passage of time and a y-axis 114 showing the relative position of the rear of the camera 20 and / or trailer 12. A zero line 116 shows the approximate centerline of the trailer 12, which can be established through calibration or estimated as part of the startup process of the method described herein. Note that the zero line 116 may vary based on the expected path of the towing vehicle 10, trailer 12, or both. Curve 110 also shows an exemplary maximum sway line 118, which represents the limit beyond which the system would preferably prevent the trailer 12 from swaying. The maximum sway line 118 may represent a point within a lane, sensed motion between images, or both.

[0107] The motion line 120 schematically illustrates the path of the trailer 12 relative to the zero line 116. One or more deviation points 122 represent areas where the rear end of the camera 20 and / or the trailer 12 has ventured beyond the maximum sway line 118, making mitigation possible. Note that the sway of the trailer 12 can also be detected by comparing the simultaneous vibration peaks shown on the sway curve graph 110, or by detecting the rate of increase in sway.

[0108] One or more mitigation points 124 represent areas where the system has applied mitigation measures to slow or reduce the swaying of trailer 12 and ideally bring it back toward the zero line 116. Note that mitigation points 124 are exemplary, and the mitigation of trailer swaying may not simply occur at the peak of motion line 120. Instead, mitigation may occur along other parts of motion line 120, such that trailer swaying is mitigated not only at the peak. Furthermore, note that mitigation may occur earlier in graph 110, for example, whenever motion line 120 exceeds the example maximum sway line 118, or whenever the system senses that motion line 120 may exceed the maximum sway line 118.

[0109] Detailed descriptions and accompanying drawings or graphics support and describe the subject matter of this document. While some best practices and other embodiments have been described in detail, various alternative designs, embodiments, and configurations exist.

[0110] Furthermore, features of any embodiments shown in the accompanying drawings or various embodiments mentioned in this specification are not necessarily to be construed as independent embodiments. Rather, each feature described in one example of an embodiment may be combined with one or more other desired features from other embodiments to obtain other embodiments not described in words or by reference to the accompanying drawings. Therefore, these other embodiments fall within the scope of the appended claims.

Claims

1. A method for detecting the motion of a trailer having a rear-facing camera and linked to a towing vehicle, comprising: The first image is captured using the camera; The second image is captured using the camera; Compare the second image with the first image; Determine a first amount of trailer movement that occurs between the second image and the first image; Use the camera to capture a third image; The fourth image is captured using the camera; Compare the fourth image with the third image; Determine a second amount of trailer movement that occurs between the fourth image and the third image; Track the first and second amounts of trailer movement to determine trailer sway; Compare the determined trailer sway with the maximum permissible sway; If the determined trailer sway is greater than the maximum permissible sway, the towing vehicle is used to mitigate the determined trailer sway, wherein mitigating the determined trailer sway includes: the towing vehicle performing one or more of differential braking, active rear steering, or active forward steering. The first or second amount of trailer movement is determined using one or more of the front camera or sensors of the towing vehicle; and If the first or second amount of trailer movement is in response to the movement of the towing vehicle, then swaying is not mitigated, even if the trailer movement exceeds the maximum permissible sway.

2. The method according to claim 1, further comprising: Determine the location of one or more lane markings in the first image; as well as Determine the position of the trailer relative to one or more lane markings in the first image.

3. The method according to claim 2, further comprising: Determine the location of one or more lane markings in the second image; as well as Determine the position of the trailer relative to one or more lane markings in the second image; as well as Determine a second amount of trailer movement relative to the one or more lane markings occurring between the second image and the first image.

4. The method of claim 1, wherein the first amount of trailer movement is a first lateral amount of trailer movement, and the method further comprises: Determine a first longitudinal amount of trailer movement that occurs between the second image and the first image.

5. The method of claim 4, wherein the second amount of trailer movement is a second lateral amount of trailer movement, and the method further comprises: Determine the second longitudinal amount of trailer movement that occurs between the fourth and third images.

6. A method for detecting the motion of a trailer having a rear-facing camera and linked to a towing vehicle, comprising: The first image is captured using the camera; The second image is captured using the camera; Compare the second image with the first image; Determine a first amount of trailer movement that occurs between the second image and the first image; Use the camera to capture a third image; The fourth image is captured using the camera; Compare the fourth image with the third image; Determine a second amount of trailer movement that occurs between the fourth image and the third image; Track the first and second amounts of trailer movement to determine trailer sway; The lateral velocity of the camera is determined from one or more of the first image, the second image, the third image, and the fourth image; The forward velocity of the camera is determined from one or more of the first image, the second image, the third image, and the fourth image; as well as The trailer length is determined based on the determined lateral speed and determined forward speed of the camera.

7. The method of claim 6, wherein mitigating the determined trailer sway further comprises: Trailer uniform braking or trailer differential braking.

8. The method of claim 6, further comprising: Determine the location of one or more lane markings in the first image; as well as Determine the position of the trailer relative to one or more lane markings in the first image.

9. The method according to claim 8, further comprising: Determine the location of one or more lane markings in the second image; as well as Determine the position of the trailer relative to one or more lane markings in the second image; as well as Determine a second amount of trailer movement relative to the one or more lane markings occurring between the second image and the first image.

10. A non-transitory computer-readable medium including content configured to cause a computing system to perform a method for detecting motion of a trailer having a rear-facing camera, the method comprising: The first image is captured using the rear-facing camera; The second image is captured using the rear-facing camera; Compare the second image with the first image; Determine a first amount of trailer movement that occurs between the second image and the first image; The third image is captured using the rear-facing camera; The fourth image is captured using the rear-facing camera; Compare the fourth image with the third image; Determine the second amount of trailer motion that occurs between the fourth and third images; Track the first and second amounts of trailer movement to determine trailer sway; Compare the determined trailer sway with the maximum permissible sway; If the motion exceeds the maximum permissible sway, the sway of the trailer is mitigated by using a towing vehicle attached to the trailer, wherein mitigating the trailer sway includes the towing vehicle performing one or more of differential braking, active rear steering, or active forward steering. Determine the location of one or more lane markings in the first image; Determine the position of the trailer relative to one or more lane markings in the first image; Determine the location of one or more lane markings in the second image; Determine the position of the trailer relative to one or more lane markings in the second image; and Determine a second amount of trailer movement relative to the lane markings that occurs between the second image and the first image.

11. The non-transitory computer-readable medium of claim 10, further comprising: The lateral velocity of the rear-facing camera is determined from one or more of the first image and the second image; Determine the forward velocity of the rear camera from one or more of the first image and the second image; as well as The trailer length is determined based on the determined lateral velocity and determined forward velocity of the rear camera.

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