Method and vehicle system for detecting an object sensor misalignment

Abstract

Method for use with an object sensor (30) located on a host vehicle (10), comprising the steps of: (a) determines whether the host vehicle (10) is traveling essentially straight ahead; (b) when the host vehicle (10) is traveling substantially straight ahead, an object is tracked by the object sensor (30) as it moves through the object sensor's field of view, so that a detected object path (76) is established, and then the suitability of the object for use in evaluating the orientation of the object sensor (30) is determined by the proximity of the detected object path (76) to the sensor's centerline (S CL ) is determined, whereby the object is more suitable the closer the detected object path (76) is to the sensor centerline (S CL ) lies; and (c) the detected object path (76) is compared with an expected object path to determine whether the object sensor (30) is misaligned.

Description

AREA

[0001] The present invention relates generally to object sensors and in particular to object sensors attached to a vehicle that can detect external objects while the vehicle is driving. BACKGROUND

[0002] Vehicles increasingly use various types of object sensors, such as those based on radar, lidar, and / or cameras, to gather information about the presence and position of external objects surrounding the host vehicle. However, it is possible for an object sensor to become misaligned or rotated in some way, causing it to provide inaccurate sensor readings. For example, if a host vehicle is involved in a minor collision, this can inadvertently damage the internal mounting or orientation of an object sensor, causing it to provide slightly inaccurate sensor readings. This can be problematic if the erroneous sensor readings are then supplied to other vehicle modules (e.g., a safety control module, an adaptive cruise control module, an automatic lane change module, etc.) and used in their calculations.

[0003] US 5,964,822 A discloses a method for measuring and compensating for a misalignment angle of a vehicle sensor. In this method, the sensor repeatedly acquires the distance and azimuth angle of a target vehicle or object, determining a target location point for each acquisition. A trajectory line of the target is estimated from these points. The misalignment angle of the sensor is estimated from the angle between the trajectory line and the sensor's center line. The misalignment is then compensated for in subsequent sensor data acquisitions. Both moving target vehicles and stationary objects can be used. Further prior art is known from DE 602 03 224 T2 and DE 197 51 004 A1. SUMMARY

[0004] The object of the invention is to provide an improved method and an improved vehicle system for detecting an object sensor misalignment.

[0005] To solve the problem, a method with the features of claim 1 and a vehicle system with the features of claim 10 are provided. Advantageous embodiments of the invention can be found in the dependent claims, the description, and the drawings.

[0006] According to one embodiment, a method for use with an object sensor located on a host vehicle is provided. The method may include the steps of: (a) determining whether the host vehicle is traveling substantially straight; (b) if the host vehicle is traveling substantially straight, tracking an object with the object sensor as it moves through the object sensor's field of view, so that a detected object path is established, and then determining whether the object is suitable for use in evaluating the object sensor's alignment by determining the proximity of the detected object path to the sensor's centerline, the closer the detected object path is to the sensor's centerline, the more suitable the object; and (c) comparing the detected object path with an expected object path to determine whether the object sensor is misaligned.

[0007] A method for use with an object sensor located on a host vehicle may include the steps of: (a) determining whether the host vehicle is traveling substantially straight; (b) if the host vehicle is traveling substantially straight, tracking an object with the object sensor by determining an object entry point, where the object enters an object sensor field of view, and an object exit point, where the object exits the object sensor field of view; (c) using the object entry point and object exit point to determine whether the object is stationary; (d) if the object is stationary, evaluating a detected object path extending from the object entry point to the object exit point by determining a detected object angle (θ). s ), which corresponds to the detected object path, and an expected object angle (θ e), which corresponds to an expected object path; and (e) the detected object angle (θ) s ) and the expected object angle (θ e ) can be used to determine if the object sensor is misaligned.

[0008] According to another embodiment, a vehicle system is provided on a host vehicle.The vehicle system may comprise: one or more vehicle sensors providing sensor readouts, wherein the vehicle sensor readouts indicate whether the host vehicle is traveling substantially straight; one or more object sensors providing sensor readouts, wherein the object sensor readouts establish a detected object path for an object as it moves through an object sensor field of view, then determining whether the object is suitable for use in evaluating the orientation of the object sensor by determining the proximity of the detected object path to the sensor centerline, the closer the detected object path is to the sensor centerline, the more suitable the object; and a control module coupled to the one or more vehicle sensors to receive the vehicle sensor readouts and coupled to the one or more object sensors to receive the object sensor readouts.The control module is designed to compare the detected object path with an expected object path to determine if the object sensor is misaligned when the host vehicle is essentially traveling straight ahead. DRAWINGS

[0009] Preferred exemplary embodiments are described below in conjunction with the accompanying drawings, wherein identical reference numerals denote identical elements, and wherein: Fig. 1. A schematic view of a host vehicle with an exemplary vehicle system; and Fig. 2 is a flowchart that represents an exemplary procedure for determining an object sensor misalignment and that applies to a vehicle system such as the one in Fig. 1 is shown, it can be used. DESCRIPTION

[0010] The exemplary vehicle system and method described herein can detect an object sensor misalignment while a host vehicle is being driven, and can do so without requiring multiple sensors with overlapping fields of view. When a misalignment is detected, the vehicle system and method can send an appropriate message to the user, the vehicle, or another source indicating that a sensor misalignment exists and should be corrected. This can be particularly advantageous in situations where other vehicle modules—for example, a safety control module, an adaptive cruise control module, an automatic lane change module, etc.—depend on and use the output of the misaligned object sensor.In an exemplary embodiment where the host vehicle is traveling straight ahead, the present method uses an object sensor to track the path of a stationary object as it moves through the sensor's field of view and compares the detected object path with an expected object path. If the detected and expected paths of the stationary object differ by more than a certain amount, the method determines that the object sensor is twisted or otherwise misaligned.

[0011] With reference to Fig. Figure 1 shows a general and schematic view of an exemplary host vehicle 10 with a vehicle system 12 installed or attached to it, wherein the vehicle system comprises one or more object sensors that may be rotated or misaligned with respect to their intended orientation. It should be noted that the present system and method can be used with any type of vehicle, including conventional passenger cars, off-road vehicles (SUVs, or sports utility vehicles), crossover vehicles, trucks, vans, buses, recreational vehicles (RVs), etc. These are merely some of the possible applications, as the system and method described herein are not limited to the exemplary embodiments shown in the figures and could be implemented by any number of different types. According to one example, the vehicle system 12 comprises vehicle sensors 20 (e.g.,an inertial navigation system (IMU of inertial measurement unit), a steering angle sensor (SAS of steering angle sensor), wheel speed sensors, etc.), object sensors 30-36 and a control module 40, and the vehicle system can provide a user with a message or other sensor status information via a user interface 50 or another component, device, module and / or system 60.

[0012] Any number of different sensors, components, devices, modules, systems, etc., can provide the vehicle system 12 with information or an input that can be used by the present method. These include, for example, the ones described in Fig. The exemplary sensors shown in Figure 1, as well as other sensors known in the art but not shown here, are included. It should be noted that the vehicle sensors 20, the object sensors 30-36, and any other sensor arranged in and / or used by the vehicle system 12 may be comprised of hardware, software, firmware, or a combination thereof. These sensors may directly detect or measure the conditions for which they are intended, or they may indirectly assess such conditions based on information supplied by other sensors, components, devices, modules, systems, etc. Furthermore, these sensors may be directly coupled to the control module 40, indirectly coupled via other electronic devices, a vehicle communication bus, a network, etc., or coupled according to any other arrangement known in the art.These sensors can be integrated into or part of another component, device, module, or system of the vehicle, etc. (e.g., vehicle or object sensors that are already part of an engine control module (ECM), traction control system (TCS), electronic stability control system (ESC), anti-lock brake system (ABS), etc.), or they can be independent components (as shown schematically in . Fig. (as shown in Figure 1), or they may be provided according to another arrangement. It is possible that some of the various sensor readouts described below may be provided by another component, device, module, system, etc., in the host vehicle 10, rather than by an actual sensor element. In some cases, multiple sensors might be used to acquire a single parameter (e.g., to provide redundancy), although this is not necessary. It should be noted that the above scenarios represent only some of the possibilities, as the vehicle system 12 is not limited to any particular sensor or sensor arrangement.

[0013] The vehicle sensors 20 provide the vehicle system 12 with various readouts, measurements, or other information that may be useful for procedure 100. For example, the vehicle sensors 20 can measure: wheel speed, wheel acceleration, vehicle speed, vehicle acceleration, vehicle dynamics, yaw rate, steering angle, longitudinal acceleration, lateral acceleration, or any other vehicle operating parameters that may be useful for procedure 100. The vehicle sensors 20 can use a variety of different sensor types and techniques, including those that use wheel speed, ground speed, accelerator pedal position, gearshift lever selection, accelerometer, engine speed, engine output, and throttle position, to name just a few.Experts will recognize that these sensors can operate according to optical, electromagnetic, or other technologies, and that other parameters can be derived or calculated from these readings (e.g., acceleration can be calculated from velocity). According to an exemplary embodiment, the vehicle sensors 20 comprise a steering angle sensor and a vehicle speed sensor.

[0014] The object sensors 30-36 provide the vehicle system 12 with sensor readouts or other information relating to one or more objects around the host vehicle 10, which can be used by the present method. In one example, the object sensors 30-36 generate sensor readouts or an output representing the presence, position, velocity, and / or acceleration of objects around the host vehicle 10. These readouts can be absolute (e.g., an object position readout) or relative (e.g., a relative distance readout relating to the distance or range between the host vehicle 10 and an object).Each of the object sensors 30-36 can be a single sensor or a combination of sensors and can be a light detection and ranging device (LIDAR device), a radio detection and ranging device (RADAR device), a laser device, a vision device (e.g., a camera, etc.), or any other detection device capable of providing the two-dimensional position of an external object. According to an exemplary embodiment, the object sensor 30 comprises a forward-facing, long-range RADAR or LIDAR device mounted at the front of the vehicle, such as on the front bumper or behind the vehicle's grille, and monitoring an area in front of the vehicle that includes the current lane plus one or more lanes on each side of the current lane.Similar types of sensors can be used for the rearward-facing object sensor 34, which is mounted at the rear of the vehicle, such as on the rear bumper or in the rear window, and for the lateral or sideways-facing object sensors 32 and 36, which are mounted on each side of the vehicle (e.g., driver's and passenger's side); these sensors may have a smaller or shorter range than their forward-facing counterparts. A camera or other vision device could be used in conjunction with such sensors, as other embodiments are also possible.

[0015] The control module 40 can comprise any variety of electronic processing devices, storage devices, input / output devices (I / O devices), and / or other known components, and can perform various control and / or communication-related functions. In an exemplary embodiment, the control module 40 comprises an electronic storage device 42 that stores various sensor readouts (e.g., sensor readouts from sensors 20 and 30-36), lookup tables or other data structures, algorithms (e.g., the algorithm included in the exemplary method described below), etc. The storage device 42 can also store relevant properties and background information regarding the host vehicle 10, such as information relating to an expected sensor placement or orientation, sensor range, sensor field of view, etc.The control module 40 may also include an electronic processing unit 44 (e.g., a microprocessor, a microcontroller, an application-specific integrated circuit (ASIC), etc.) that executes instructions for software, firmware, programs, algorithms, scripts, etc., stored in the memory unit 42 and that can monitor the processes and procedures described herein. The control module 40 may be electronically connected to other vehicle equipment, modules, and systems via suitable vehicle communication channels and may interact with them when necessary. These are, of course, only some of the possible arrangements, functions, and capabilities of the control module 40, as other embodiments could also be used.

[0016] Depending on the specific embodiment, the control module 40 can be an independent vehicle module (e.g., an object detection controller, a safety controller, etc.), it can be incorporated into or included within another vehicle module (e.g., a safety control module, an adaptive cruise control module, an automatic lane change module, a parking assistance module, a brake control module, a steering control module, etc.), or it can be part of a larger network or system (e.g., a traction control system (TCS), an electronic stability control system (ESC), an anti-lock braking system (ABS), a driver assistance system, an adaptive cruise control system, a lane departure warning system, etc.), to name just a few possibilities. The control module 40 is not limited to any particular embodiment or arrangement.

[0017] The user interface 50 exchanges information or data with occupants of the host vehicle 10 and can comprise any combination of visual, acoustic, and / or other types of components for this purpose. Depending on the specific embodiment, the user interface 50 can be an input / output device that can both receive information from the driver (e.g., a touchscreen display or a voice-recognition human-machine interface), an input device only (e.g., a microphone), an output device only (e.g., a loudspeaker, an instrument panel display, or a visual indicator in the rearview mirror), or another component, and can also provide information to these components.The user interface 50 can be an independent module; it can be part of a rearview mirror assembly, part of an infotainment system, or part of another module, device, or system in the vehicle; it can be mounted on an instrument panel (e.g., with a driver information center (DIC)); it can be projected onto a windshield (e.g., with a head-up display); or it can be integrated into an existing audio system, to name a few examples. In the case of... Fig. In the exemplary embodiment shown in Figure 1, the user interface 50 is located in an instrument panel of the host vehicle 10 and alerts a driver regarding a misaligned object sensor by sending a written or graphical message or the like. In another embodiment, the user interface 50 sends an electronic message (e.g., a diagnostic trouble code (DTC), etc.) to an internal or external destination, alerting it to the sensor misalignment. Other suitable user interfaces may also be used.

[0018] Module 60 represents any vehicle component, vehicle equipment, vehicle module, vehicle system, etc., that requires a sensor readout from one or more object sensors 30-36 to operate. For example, Module 60 could be an active safety system, an adaptive cruise control system (ACC), an automated lane change system (LCX), or any other vehicle system that uses sensor readouts regarding nearby vehicles or objects for operation.In the example of an adaptive cruise control (ACC) system, the control module 40 can warn the ACC system 60 to ignore sensor readings from a specific sensor if the present method determines that the sensor is misaligned; inaccuracies in the sensor readings could negatively affect the performance of the ACC system 60. Depending on the specific embodiment, the module 60 can be an input / output device capable of both receiving information from and providing information to the control module 40, and it can be an independent vehicle electronics module or it can be part of a larger network or system (e.g.,a traction control system (TCS), an electronic stability control system (ESC), an anti-lock braking system (ABS), a driver assistance system, an adaptive cruise control system (ACC), a lane departure warning system, etc.), to name a few possibilities. It is even possible for module 60 to be combined with or integrated into control module 40, as module 60 is not limited to any particular embodiment or arrangement.

[0019] Again, the preceding description of the exemplary vehicle system 12 and the drawing in Fig. 1 represents only one possible embodiment, since the following method is not limited to use with only this system. Instead, any number of other system arrangements, combinations, and architectures can be used, including those that differ significantly from the one described in Fig. 1. Distinguish between the two shown.

[0020] Now on Fig. 2 With reference to this, an exemplary procedure 100 is shown, which can be used with the vehicle system 12 to determine whether one or more object sensors 30-36 are misaligned, twisted, or otherwise improperly oriented. As mentioned above, an object sensor may become misaligned as a result of a collision, a significant pothole or other interruption in the road surface, or simply through normal wear and tear over the years of vehicle operation, to name a few possibilities. The procedure 100 can be initiated or started in response to any number of different events and can be executed on a periodic, aperiodic, and / or other basis, since the procedure is not restricted to any particular initialization sequence.According to some non-restrictive examples, the procedure 100 can run continuously in the background, can be initiated after an ignition event, or can be started after a collision, to name a few possibilities.

[0021] Starting with step 110, the procedure acquires sensor readouts from one or more vehicle sensors 20. The acquired readouts may include: wheel speed, wheel acceleration, vehicle speed, vehicle acceleration, vehicle dynamics, yaw rate, steering angle, longitudinal acceleration, lateral acceleration, or any other suitable vehicle operating parameter. In an example, step 110 receives steering angle readouts, yaw rate readouts, and / or other readouts indicating whether the host vehicle 10 is traveling substantially straight ahead, as well as vehicle speed readouts indicating how fast the host vehicle is moving. Those skilled in the art will recognize that step 110 can acquire or otherwise obtain other sensor readouts, as the aforementioned readouts represent only some of the possibilities.

[0022] Step 114 then determines whether the host vehicle 10 is moving or traveling essentially straight ahead. If the host vehicle is traveling straight ahead—for example, along a stretch of highway or other road—certain assumptions can be made that simplify the calculations performed by procedure 100, thereby making the corresponding algorithm less weighty and less resource-intensive, as explained in more detail below. In one exemplary embodiment, step 114 evaluates the sensor readings from the previous step (e.g., steering angle readings, yaw rate readings, wheel speed readings, etc.) and uses this information to determine whether the host vehicle 10 is traveling essentially straight ahead.This step may require that the steering angle or yaw rate be less than a predetermined threshold for a certain duration or distance, or that the various wheel speed readings be within a predetermined range of each other, or that other techniques be used to evaluate the linearity of the host vehicle's path. It is even possible that step 114 uses information from some type of GPS-based vehicle navigation system to determine whether the host vehicle is traveling essentially straight. The term "essentially straight," and its various forms, is intended to encompass those vehicle paths that are straight or linear enough for the application of the algorithmic assumptions described later; it does not mean that the host vehicle must be traveling perfectly straight or in a perfectly straight direction.The linear status of the vehicle path could be provided by another device, module, system, etc., located in the host vehicle, as this information may already be available. If the host vehicle 10 is essentially moving in a straight line, the procedure proceeds to step 118; otherwise, the procedure loops back to the beginning.

[0023] Step 118 acquires sensor readouts from one or more object sensors 30-36 located on the host vehicle. The sensor readouts indicate whether an object has entered the field of view of a particular object sensor, as explained, and can be provided in a variety of different shapes. In one embodiment, Step 118 monitors a field of view 70 of the object sensor 30 located at the front of the host vehicle 10. The field of view 70 is, in a sense, pie-shaped and is located in front of the host vehicle, but the field of view can vary depending on the sensor's range (e.g., long range, short range, etc.), the sensor type (e.g., radar, LiDAR, LaDAR, laser, etc.), the sensor's location and mounting orientation (e.g., a front sensor 30, side sensors 32 and 36, a rear sensor 34, etc.), or some other characteristics.Step 118 can be combined with step 114 or any other suitable step in the procedure, as it does not need to be performed separately.

[0024] Step 122 determines whether an object is present in the field of view of one or more of the object sensors. For example, Step 122 monitors the field of view 70 for the forward-facing object sensor 30 and uses any number of suitable techniques to determine whether one or more objects have entered the field of view. The techniques employed by this step can vary for different environments (e.g., high-density environments such as urban areas, low-density environments such as rural areas, etc.). Step 122 may consider and evaluate multiple objects in the field of view 70 simultaneously, including both moving and stationary objects, as well as other object scenarios. This step can employ a variety of suitable filtering and / or other signal processing techniques to evaluate the sensor readouts and determine whether an object actually exists.Some non-restrictive examples of such techniques include the use of predetermined signal-to-noise ratio (SNR) thresholds in the presence of background noise, as well as other well-known methods. If step 122 detects that an object is present, the procedure proceeds to step 126; otherwise, the procedure loops back to the beginning for further monitoring.

[0025] Next, step 126 tracks the object as it moves through the field of view of one or more of the object sensors. By tracking or monitoring the object as it passes through a sensor's field of view, this step can develop or establish a detected object path that can be useful in subsequent steps. The detected object path can, for example, indicate whether the object is stationary or moving. According to an exemplary embodiment, step 126 records information about an object entry point 72 and an object exit point 74 for each object that enters the field of view 70. Some examples of the types of information or data that could be stored for each object entry and / or exit point include a time associated with each point, a position associated with each point (e.g., Cartesian, polar, or other coordinates), a distance from the host vehicle, etc.) or some other suitable data. For example, step 126 can determine the time and position of an object entering the field of view 70 and store this data in conjunction with the object entry point 72, and determine the time and position of the object exiting or leaving the field of view and store this data in conjunction with the object exit point 74. It is also possible for step 126 to track or monitor the object while it is within the object sensor's field of view—not just at the boundaries of the field of view—and evaluate and / or store the resulting data. In one exemplary embodiment, the object is tracked across the field of view 70 by continuously generating and updating temporary data points 68 until the object is no longer detected (i.e.,Object exit point 74), where at this point only the first and last data points are stored in the storage device 42; storing only the first and last data points can reduce the amount of stored data and free up storage and / or computing resources. Depending on the specific application, information regarding the temporary or intermediate data points 68 can also be stored and used. Step 126 can employ techniques for filtering or verifying the data, such as averaging or smoothing two or more data points, etc. Other embodiments are also possible.

[0026] Step 130 then determines whether the detected object can be used to evaluate the alignment or orientation of the object sensor. Two criteria that can be considered by Step 130 include the length of the object path and whether the object is stationary. For example, if the object barely intersects or passes through the field of view 70, it might produce an object path 76' of a short length (d') that is not long enough for exact use in Procedure 100 (the algorithmic assumptions or shortcuts described below are typically more accurate with sufficiently long object paths). One way for Step 130 to determine whether the detected object is a good candidate for use in the present procedure involves considering the length (d) between the object entry point 72 and the object exit point 74 (i.e.,to calculate the object path length) and then compare this length with a path length threshold. The path length threshold, or minimum path length, depends on a number of factors, including the type, quality, and / or location of the object sensor being evaluated. For example, if the object sensor 30 is a low-quality, far-range sensor, a longer path length threshold may be required; if it is a higher-quality sensor or a near-range sensor, a shorter path length threshold may suffice. According to the invention, step 130 determines the adequacy or usability of the detected object by considering where the object path runs through the field of view (the closer to the sensor centerline S, the better). CL, the more useful it can be). As mentioned above, the object path length is only one of the possible criteria that can be considered by step 130 to determine the adequacy of the captured object; whether the object is stationary is another.

[0027] In the present method, stationary objects are preferred over normally moving objects for the purpose of evaluating the alignment or orientation of an object sensor. Thus, step 130 can verify whether the detected object is stationary or moving, and this can be done in a number of different ways. According to one exemplary embodiment, step 130 determines the apparent or mean velocity of the detected object while it is in the field of view 70 and then compares this to the velocity of the host vehicle 10; if the difference between the two velocities is less than a certain amount, the object is considered stationary. In one example, step 130 calculates the apparent or mean velocity of the detected object by dividing the distance between the object's entry and exit points by the time between these points: Object velocity == (Object exit point position − Object entry point position) / (Object exit point time − Object entry point time)

[0028] The above calculation can be performed in Cartesian coordinates, polar coordinates, or any other suitable coordinate system, and the accuracy of the calculation is based, at least in part, on assumptions that the vehicle follows a substantially straight or linear path. If the host vehicle 10 has been driven around a bend or curve, the assumptions associated with this calculation may no longer hold true. Performing the above calculation avoids the need for the host vehicle 10 to use expensive and sophisticated object sensors that internally calculate the object's velocity, as such sensors can incur undesirable costs for the vehicle. Step 130 can obtain the vehicle's velocity by querying the control module 40 or another source, allowing it to compare the velocities of the object and the vehicle.If the difference between the speeds of the vehicle and the object is less than a speed threshold (e.g., a fixed threshold, a variable threshold that is a fraction or percentage of the vehicle speed, or another type of threshold), the detected object is likely to be stationary; otherwise, the method assumes that the object is a moving target, such as another vehicle. In one embodiment, step 130 compares the difference between the speeds of the vehicle and the object to a fixed threshold, such as 8 km / h (5 mph), which is chosen to account for normal sensor noise.

[0029] In the preceding example, which used two criteria, step 130 checks whether the object path length is sufficiently long and whether the object is stationary. If both of these criteria are met, the exemplary procedure concludes that the detected object is a good candidate for use in the sensor alignment techniques described below and proceeds to step 146. If both criteria are not met, the procedure returns to step 110 and continues searching for a suitable object to use for evaluating the object sensor's alignment. It should be noted that other criteria and combinations of criteria can be used for evaluation in step 130, as the present procedure is not limited to the exemplary criteria described above.

[0030] At this point, the procedure has determined that the vehicle is moving essentially straight ahead (step 114), has detected the presence of an object in the object sensor's field of view (step 122), has determined that the object is suitable for use in evaluating a sensor alignment (step 130), and now the procedure can evaluate the alignment or orientation of the object sensor in question.

[0031] Step 146 evaluates a sensor orientation by measuring a detected object angle (θ). s ) and an expected object angle (θ e ) are determined and then these two angles are compared. The measured object angle (θ) s ) generally refers to the detected or measured angle of the object path 76, and according to the in Fig. In the embodiment shown in 1, the detected object angle (θ) represents s) the angle between the object path 76 (i.e. the line drawn between object entry and exit points 72, 74) and the sensor centerline S CL The expected object angle (θ) e ) generally refers to the expected or predetermined mounting angle of the object sensor in question, and the expected object angle (θ) e ) represents according to Fig. 1 the angle between the vehicle centerline V CL and the sensor centerline S CL The expected object angle (θ) e ) can be the known mounting orientation of the object sensor in question and is usually determined when the vehicle is designed, tested, or at another stage of development, and can be stored in the memory device 42 or elsewhere. It should be noted that the expected object angle (θ) e) from the orientation of approximately 20° shown in the drawing. For example, the object sensor 30 may be intentionally mounted according to other orientations - for example θ e = 5°, 10°, 30°, 45° etc. The exact orientation or placement of the object sensor in question may vary depending on the type, quality, and intended purpose of the object sensor, as well as the specific application in which it is used. Furthermore, the actual angles, coordinate frames, etc., used to determine (θ) may vary. s ) and (θ e ) to represent, from the examples shown here.

[0032] Step 154 ​​then determines whether the object sensor is misaligned or otherwise rotated. In one embodiment, this step compares the expected object angle (θ). e ), which is stored in memory 42, with the detected object angle (θ s), which was recently determined to calculate the difference between the two angles. The signs of these angles should be taken into account; for example, the recorded object angles (θ) can be s ) on the right side of the sensor centerline S CL have a sign and can be the recorded object angles (θ) s ) on the left side of the sensor centerline S CL (like the one in Fig.(1 shown) have a different sign. If the difference between these two angles exceeds an object angle threshold, it is determined that the object sensor is misaligned. As before, the object angle threshold can be a fixed threshold (e.g., 0°, 1°, 2°, 5°, etc.), a variable threshold (e.g., a percentage or fraction of the detected or expected object angle), or a threshold that depends on the sensor used, the noise level of the sensor, the vehicle speed, etc., or another suitable factor. If step 154 ​​determines that the difference between the expected and detected object angle θ e and θ sIf the angle difference is greater than the object angle threshold, the object sensor in question is considered misaligned or otherwise rotated. If the angle difference is less than the object angle threshold, the object sensor is considered correctly aligned. It should be noted that step 154 ​​can not only detect sensor misalignment, but it can also identify the sensor that is misaligned or rotated without information from any other object sensor. Appropriate tolerances should be included in the object angle threshold to account for typical manufacturing and mounting errors. Experts will also recognize that appropriate use of the signs of the angles (i.e., positive or negative) will aid in identifying misalignment even if the sensor spans the same but opposite angle (e.g., misalignment will be detected if θ s = -θ e).

[0033] Experts will recognize that the present method may employ one or more redundancy checks or other techniques to ensure that a finding of object sensor misalignment is correct. For example, the method may employ a type of programming loop that requires the method to find that the sensor is misaligned for a certain number of consecutive iterations (e.g., five iterations) or a certain ratio of iterations (e.g., four out of five iterations) before concluding that the sensor is indeed misaligned. In another example, the present method may require that several stationary objects be identified and used before concluding that an object sensor is misaligned.In such a case, step 154 ​​would need to detect sensor misalignment using multiple and different stationary objects. In yet another example, method 100 can be used in conjunction with object sensors with an overlapping field of view or another type of hardware redundancy to ensure the accuracy of the detections. Certainly, other types of redundancy and techniques are also possible.

[0034] If the previous step determines that the object sensor in question is misaligned, step 158 can take one or more corrective actions. Some examples of appropriate corrective actions include: sending a warning message to the driver via user interface 50, to another part of the host vehicle such as module 60, or to a remotely located backend device (not shown); setting a sensor fault flag or generating a diagnostic trouble code (DTC); or disabling another device, module, system, and / or feature in the host vehicle that depends on sensor readings from the misaligned object sensor for proper operation, to name a few possibilities.In one embodiment, step 158 sends a warning message to the user interface 50, informing the driver that the object sensor 30 is misaligned, and sends command signals to the module 60, instructing the module to avoid using sensor readouts from the misaligned or twisted object sensor until it can be repaired. Certainly, other types and combinations of corrective actions are also possible.

[0035] The exemplary procedure described herein can be encompassed by a lightweight algorithm that is less memory- and processor-intensive than previous methods that capture and analyze large collections of data points. For example, using a captured object path instead of all data points between the object's entry and exit points can reduce the memory and processor load on the system. This algorithmic efficiency allows the procedure to be executed while the host vehicle is being driven, rather than requiring the sensor to be placed in an alignment mode and driven along a predefined route, or requiring the host vehicle to be taken to a workshop and checked with specialized diagnostic tools.Furthermore, it is not necessary for the host vehicle to use 10 expensive object sensors that internally calculate and provide the speed of detected objects, or for multiple object sensors with overlapping fields of view to be required, as some systems do.

[0036] It should be understood that the preceding description is not a definition of the invention, but rather a description of one or more preferred exemplary embodiments of the invention. The invention is not limited to the specific embodiment(s) disclosed herein, but is merely defined by the claims below. Furthermore, the statements contained in the preceding description refer to specific embodiments and should not be considered as limitations on the scope of protection of the invention or on the definition of terms used in the claims, unless a term or phrase is expressly defined above. Various other embodiments and various modifications and variations of the disclosed embodiment(s) will be apparent to those skilled in the art.For example, the specific combination and sequence of steps is only one possibility, since the present method may include a combination of steps that has fewer, more, or different steps than those shown here. All such other embodiments, modifications, and variations are to be included within the scope of protection of the appended claims.

[0037] As used in this description and in the claims, the terms "for example," "e.g.," "such as," "as," and "as," and the verbs "comprise," "exhibit," "include," and their other verb forms, when used in conjunction with a list of one or more components or one or more other elements, shall each be considered to have an open end, meaning that the list shall not be considered to exclude other, additional components or elements. Other terms shall be considered to encompass their broadest reasonable meaning unless used in a context that requires a different interpretation.

Claims

[1] Method for use with an object sensor (30) located on a host vehicle (10), comprising the steps of: (a) determines whether the host vehicle (10) is traveling essentially straight ahead; (b) when the host vehicle (10) is traveling substantially straight ahead, an object is tracked by the object sensor (30) as it moves through the object sensor's field of view, so that a detected object path (76) is established, and then the suitability of the object for use in evaluating the orientation of the object sensor (30) is determined by the proximity of the detected object path (76) to the sensor's centerline (S CL ) is determined, whereby the object is more suitable the closer the detected object path (76) is to the sensor centerline (S CL ) lies; and (c) the detected object path (76) is compared with an expected object path to determine whether the object sensor (30) is misaligned. [2] Method according to claim 1, wherein step (a) further comprises receiving sensor readouts from a steering angle sensor and / or a yaw rate sensor and / or a wheel speed sensor and using the sensor readouts from the steering angle sensor and / or the yaw rate sensor and / or the wheel speed sensor to determine whether the host vehicle (10) is traveling substantially straight ahead. [3] Method according to claim 1, wherein step (b) further comprises tracking the object with the object sensor (30) as it moves through the object sensor's field of view by storing information regarding an object entry point (72) and an object exit point (74). [4] Method according to claim 3, wherein the information regarding the object entry point (72) comprises a time and position of the object at which and where it enters the object sensor field of view, and the information regarding the object exit point (74) comprises a time and position of the object at which and where it exits the object sensor field of view. [5] Method according to claim 1, wherein step (c) further comprises comparing the detected object path (76) with the expected object path by measuring a detected object angle (θ s ), which corresponds to the detected object path (76), and an expected object angle (θ e ), which corresponds to the expected object path, are determined, and then these two angles are compared. [6] Method according to claim 5, wherein step (c) further comprises that the difference between the detected object angle (θ s ) and the expected object angle (θe ) is determined and the difference is compared with an object angle threshold. [7] The method of claim 1, further comprising the step of: (d) one or more corrective actions are taken when it is determined that the object sensor (30) is misaligned. [8] Method according to claim 7, wherein step (d) further comprises sending a warning message to a user interface (50) informing the driver that the object sensor (30) is misaligned. [9] Method according to claim 7, wherein step (d) further comprises sending command signals to a module (60) on the host vehicle (10) instructing the module (60) to avoid using sensor readouts from the misaligned sensor (30). [10] Vehicle system on a host vehicle (10), comprising: one or more vehicle sensors (20) which provides or provide sensor readouts, wherein the vehicle sensor readouts indicate whether the host vehicle (10) is substantially traveling straight ahead; one or more object sensors (30, 32, 34, 36) which provide or provide sensor readouts, wherein the object sensor readouts establish a detected object path (76) for an object as it moves through an object sensor field of view, and then determine whether the object is suitable for use in evaluating the orientation of the object sensor (30) by the proximity of the detected object path (76) to the sensor centerline (S CL ) is determined, whereby the object is more suitable the closer the detected object path (76) is to the sensor centerline (S CL ) lies; and a control module (40) coupled to the one or more vehicle sensors (20) to receive the vehicle sensor readouts and coupled to the one or more object sensors (30, 32, 34, 36) to receive the object sensor readouts, wherein the control module (40) is configured to compare the detected object path (76) with an expected object path to determine whether the object sensor (30) is misaligned when the host vehicle (10) is traveling substantially straight ahead.

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