System and method for determining trailer axle count and position

Abstract

A method of determining a trailer axle count and axle position of a trailer relative to a vehicle. The method includes receiving vehicle operating characteristics from at least one sensor on a vehicle and determining whether the vehicle encounters a bump on a roadway based on at least one of the vehicle operating characteristics. The method determines whether at least one trailer axle encounters the bump and analyzes a relative time difference between when the vehicle encounters the bump and when the at least one trailer axle encounters the bump. The method uses the relative time to determine a trailer axle count and estimate a position of the at least one trailer axle relative to the vehicle.

Description

[0001] Introduction Technical Field

[0002] This disclosure relates to determining the position of a trailer axle, and more particularly, to determining the position of a trailer axle relative to a tow vehicle. Background Art

[0003] A driver of a tow vehicle encounters several obstacles when towing a trailer. Towing a trailer can affect the dynamics of the tow vehicle, and due to the added length that the trailer adds to the tow vehicle, the driver of the tow vehicle may operate the vehicle differently. Additionally, during certain maneuvers, such as backing up, the trailer can articulate relative to the tow vehicle, which requires a change in the input to the tow vehicle to back up compared to backing up without a trailer. Further, the added weight of the trailer can affect the tow vehicle's ability in braking situations. Summary of the Invention

[0004] Disclosed herein is a method for determining a trailer axle count and the position of an axle of a trailer relative to a vehicle. The method includes receiving vehicle operating characteristics from at least one sensor on the vehicle and determining whether the vehicle has encountered a bump on the road based on at least one of the vehicle operating characteristics. The method determines whether at least one trailer axle has encountered the bump and analyzes a relative time difference between when the vehicle has encountered the bump and when the at least one trailer axle has encountered the bump. The method uses the relative time to determine the trailer axle count and estimate the position of the at least one trailer axle relative to the vehicle.

[0005] Another aspect of the present disclosure may include determining an enabling excitation of the vehicle when the vehicle has encountered the bump, and the enabling excitation includes identifying at least one of the following: the steering angle of the vehicle is within a predetermined range, the speed of the vehicle is greater than a predetermined speed, or the wheel speed difference between laterally spaced wheels on the vehicle is less than a predetermined value.

[0006] Another aspect of the present disclosure may include confirming the presence of a trailer coupled to the vehicle when the position of the at least one trailer axle relative to the vehicle is estimated.

[0007] Another aspect of the present disclosure may be that the at least one sensor includes at least one of a ride height sensor, a wheel speed sensor, or an inertial measurement unit located on the vehicle. Determining whether the vehicle has encountered the bump is based on determining the magnitude of the rate of change of the at least one vehicle operating characteristic.

[0008] Another aspect of the present disclosure may be that at least one of the sensors is located on the vehicle, and determining whether the at least one trailer axle has encountered the bump is based on determining the magnitude of the rate of change of at least one vehicle operating characteristic within a time range after the vehicle has encountered the bump.

[0009] Another aspect of the present disclosure may include determining the status of the trailer by determining whether the magnitude of the rate of change of at least one vehicle operating characteristic is within a predetermined range.

[0010] Another aspect of the present disclosure may include receiving a second set of vehicle operating characteristics from at least one of the sensors on the vehicle and determining whether the vehicle has encountered a second bump on the road based on at least one of the second set of vehicle operating characteristics. The method determines whether at least one trailer axle has encountered the bump and analyzes the relative time difference between when the vehicle has encountered the bump and when the at least one trailer axle has encountered the bump to determine a second trailer axle count and estimate a second position of the at least one trailer axle relative to the vehicle. If the difference between the second position of the at least one trailer axle and the position of the at least one trailer axle exceeds a predetermined threshold, the method identifies a change in the operating status of the trailer.

[0011] Another aspect of the present disclosure may be that determining whether the vehicle has encountered the bump includes determining an estimated wheelbase length of the vehicle based on the speed of the vehicle and the relative time difference between when the front wheels of the vehicle have encountered the bump and when the rear wheels of the vehicle have encountered the bump.

[0012] Another aspect of the present disclosure may be that if the estimated wheelbase length is within a predetermined range of a predetermined wheelbase length of the vehicle, the vehicle has encountered the bump.

[0013] Another aspect of the present disclosure may be that determining the estimated wheelbase length includes integrating the speed of the vehicle from when one of a pair of front wheels has encountered the bump until one of a pair of rear wheels has encountered the bump.

[0014] Another aspect of the present disclosure may be that determining whether the at least one trailer axle has encountered the bump is based on at least one of longitudinal jerk, yaw acceleration, or pitch acceleration measured by the at least one vehicle sensor exceeding a corresponding predetermined threshold.

[0015] Another aspect of the present disclosure may be that determining whether the at least one trailer axle has encountered the bump includes identifying a decrease in the oscillation amplitude of at least one of longitudinal acceleration, yaw acceleration, or pitch acceleration.

[0016] Disclosed herein is a non - transitory computer - readable medium embodying programming instructions that are operable, when executed by a processor, to perform a method. The method includes receiving vehicle operating characteristics from at least one sensor on a vehicle and determining whether the vehicle has encountered a bump on a road based on at least one of the vehicle operating characteristics. The method determines whether at least one trailer axle has encountered the bump and analyzes a relative time difference between when the vehicle encounters the bump and when the at least one trailer axle encounters the bump. The method uses the relative time to determine a trailer axle count and estimate the position of the at least one trailer axle relative to the vehicle.

[0017] Disclosed herein is a vehicle assembly. The vehicle assembly includes a vehicle body having a front axle supported by a pair of front wheels and a rear axle supported by a pair of rear wheels, and at least one sensor configured to measure movement of at least one of the front axle, the rear axle, or the vehicle body. The vehicle assembly further includes a controller in electrical communication with the at least one sensor. The controller is configured to receive vehicle operating characteristics from at least one sensor on the vehicle and determine whether the vehicle has encountered a bump on a road based on at least one of the vehicle operating characteristics. The controller is further configured to determine whether at least one trailer axle has encountered the bump and analyze a relative time difference between when the vehicle encounters the bump and when the at least one trailer axle encounters the bump to estimate at least one of a trailer axle count or position.

[0018] The present application discloses the following embodiments.

[0019] 1. A method for determining a trailer axle count and the axle position of a trailer relative to a vehicle, the method comprising: receiving a plurality of vehicle operating characteristics from at least one sensor on the vehicle; determining whether the vehicle has encountered a bump on a road based on at least one of the plurality of vehicle operating characteristics; determining whether at least one trailer axle has encountered the bump; and analyzing a relative time difference between when the vehicle encounters the bump and when the at least one trailer axle encounters the bump to determine a trailer axle count and estimate the position of the at least one trailer axle relative to the vehicle.

[0020] 2. The method according to embodiment 1, including determining an enabling excitation of the vehicle when the vehicle encounters the bump, wherein determining the enabling excitation includes identifying at least one of the following: the steering angle of the vehicle is within a predetermined range, the speed of the vehicle is greater than a predetermined speed, or the wheel speed difference between laterally - separated wheels on the vehicle is less than a predetermined value.

[0021] 3. The method according to Embodiment 1 includes confirming the presence of a trailer coupled to a vehicle when the position of the at least one trailer axle relative to the vehicle is estimated.

[0022] 4. The method according to Embodiment 1, wherein the at least one sensor includes at least one of a ride height sensor, a wheel speed sensor, or an inertial measurement unit located on the vehicle, and determining whether the vehicle has encountered the bump is based on determining the magnitude of the rate of change of at least one of the plurality of vehicle operating characteristics.

[0023] 5. The method according to Embodiment 1, wherein the at least one sensor is located on the vehicle, and determining whether the at least one trailer axle has encountered the bump is based on determining the magnitude of the rate of change of at least one of the plurality of vehicle operating characteristics within a time range after the vehicle has encountered the bump.

[0024] 6. The method according to Embodiment 5 includes determining the state of the trailer by determining whether the magnitude of the rate of change of the at least one vehicle operating characteristic is within a predetermined range.

[0025] 7. The method according to Embodiment 1 includes: Receiving a second plurality of vehicle operating characteristics from the at least one sensor on the vehicle; Determining whether the vehicle has encountered a second bump on the road based on at least one of the second plurality of vehicle operating characteristics; Determining whether the at least one trailer axle has encountered the bump; Analyzing the relative time difference between when the vehicle has encountered the bump and when the at least one trailer axle has encountered the bump to determine a second trailer axle count and estimate a second position of the at least one trailer axle relative to the vehicle; and determining a change in the operating state of the trailer if the difference between the second position of the at least one trailer axle and the position of the at least one trailer axle exceeds a predetermined threshold.

[0026] 8. The method according to Embodiment 1, wherein determining whether the vehicle has encountered the bump includes determining an estimated wheelbase length of the vehicle based on the speed of the vehicle and the relative time difference between when the front wheels of the vehicle have encountered the bump and when the rear wheels of the vehicle have encountered the bump.

[0027] 9. The method according to Embodiment 8, wherein if the estimated wheelbase length is within a predetermined range of a predetermined wheelbase length of the vehicle, the vehicle has encountered the bump.

[0028] 10. The method according to embodiment 8, wherein determining the estimated wheelbase length includes: integrating the speed of the vehicle from when one of a pair of front wheels encounters the bump until one of a pair of rear wheels encounters the bump.

[0029] 11. The method according to embodiment 8, wherein determining whether the at least one trailer axle has encountered the bump is based on when at least one of the at least one vehicle sensor configured to measure longitudinal jerk, yaw acceleration, or pitch acceleration exceeds a corresponding predetermined threshold.

[0030] 12. The method according to embodiment 11, wherein determining whether the at least one trailer axle has encountered the bump includes identifying a decrease in the amplitude of oscillations of at least one of longitudinal jerk, yaw acceleration, or pitch acceleration.

[0031] 13. A non - transitory computer - readable medium embodying programming instructions that, when executed by a processor, are operable to perform a method, the method including: Receiving a plurality of vehicle operating characteristics from at least one sensor on the vehicle; Determining whether the vehicle has encountered a bump on the road based on at least one of the plurality of vehicle operating characteristics; Determining whether the at least one trailer axle has encountered the bump; and Analyzing a relative time difference between when the vehicle has encountered the bump and when the at least one trailer axle has encountered the bump to estimate at least one of a trailer axle count or the position of the at least one trailer axle relative to the vehicle.

[0032] 14. The computer - readable medium according to embodiment 13, including determining an enabling excitation of the vehicle when the vehicle has encountered the bump, wherein determining the enabling excitation includes identifying at least one of: the steering angle of the vehicle is within a predetermined range, the speed of the vehicle is greater than a predetermined speed, or the wheel speed difference between laterally - spaced wheels on the vehicle is less than a predetermined value.

[0033] 15. The computer - readable medium according to embodiment 14, wherein determining whether the vehicle has encountered the bump is based on determining the magnitude of the rate of change of at least one of the plurality of vehicle operating characteristics, and determining whether the at least one trailer axle has encountered the bump is based on determining the magnitude of the rate of change of at least one of the plurality of vehicle operating characteristics within a time range after the vehicle has encountered the bump.

[0034] 16. The computer-readable medium according to embodiment 13, wherein determining whether the vehicle has encountered the bump includes determining an estimated wheelbase length of the vehicle based on the speed of the vehicle and a relative time difference between when the front wheels of the vehicle encounter the bump and when the rear wheels of the vehicle encounter the bump.

[0035] 17. The computer-readable medium according to embodiment 16, wherein determining whether the at least one trailer axle has encountered the bump is based on when at least one of the at least one vehicle sensor configured to measure longitudinal jerk, yaw acceleration, or pitch acceleration exceeds a corresponding predetermined threshold; and wherein determining whether the at least one trailer axle has encountered the bump includes identifying a decrease in the oscillation amplitude of at least one of longitudinal acceleration, yaw acceleration, or pitch acceleration.

[0036] 18. A vehicle assembly, comprising: A vehicle body; A front axle supported by a pair of front wheels and a rear axle supported by a pair of rear wheels; At least one sensor configured to measure movement of at least one of the front axle, the rear axle, or the vehicle body; A controller in electrical communication with the at least one sensor, the controller being configured to: Receive a plurality of vehicle operating characteristics from at least one sensor on the vehicle; Determine whether the vehicle has encountered a bump on the road based on at least one of the plurality of vehicle operating characteristics; Determine whether the at least one trailer axle has encountered the bump; and Analyze a relative time difference between when the vehicle encounters the bump and when the at least one trailer axle encounters the bump to estimate at least one of a trailer axle count or a position of the at least one trailer axle relative to the vehicle.

[0037] 19. The vehicle assembly according to embodiment 18, wherein the at least one sensor is located on the vehicle, and determining whether the vehicle has encountered the bump is based on determining an amplitude of a rate of change of at least one of the plurality of vehicle operating characteristics; and wherein determining whether the at least one trailer axle has encountered the bump is based on determining an amplitude of a rate of change of at least one of the plurality of vehicle operating characteristics within a time range after the vehicle has encountered the bump.

[0038] 20. The vehicle assembly according to embodiment 18, wherein determining whether the vehicle has encountered the bump includes determining an estimated wheelbase length of the vehicle based on the speed of the vehicle and a relative time difference between when the front wheels of the vehicle encounter the bump and when the rear wheels of the vehicle encounter the bump; and Determining whether the at least one trailer axle has encountered the bump is based on when at least one of the at least one vehicle sensor configured to measure longitudinal jerk, yaw acceleration, or pitch acceleration exceeds a corresponding predetermined threshold. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a schematic diagram of a vehicle system including a vehicle and a trailer.

[0040] Figure 2 illustrates an example method for determining trailer axle count and position.

[0041] Figure 3 illustrates the Figure 1 measured over a period of time

[0042] Figure 4A illustrates the Figure 3 rate of change of the state parameter measured over the period of time.

[0043] Figure 4B illustrates a graphical representation in amplitude-phase form of a time-based analysis obtained from the rate of change illustrated in FIG. 4 over the period of time.

[0044] Figure 5 illustrates a graphical representation of an estimate of trailer axle position.

[0045] Figure 6 illustrates another example method for determining trailer axle count and position.

[0046] Figure 7 is Figure 1 graphical representation of the movement of the front axle on a

[0047] Figure 8 is Figure 1 graphical representation of the movement of the rear axle on a

[0048] Figure 9 is a graphical representation of an example of the inertial movement of a Figure 1 vehicle when two axles on a trailer pass over a speed bump.

[0049] Figure 10 is a graphical representation of an example for determining trailer axle count.

[0050] Figure 11 is a graphical representation of an example for determining trailer axle position. DETAILED DESCRIPTION

[0051] The present disclosure may admit of many different forms of embodiments. Representative examples of the present disclosure are shown in the drawings and are described herein in detail as non-limiting examples of the disclosed principles. To this end, elements and limitations described in the abstract, introduction, summary of the invention, and detailed description sections but not explicitly set forth in the claims should not be incorporated into the claims by implication, inference, or otherwise, either individually or collectively.

[0052] For the purposes of this description, unless otherwise specified, the use of the singular includes the plural and vice versa, the terms "and" and "or" shall be both conjunctive and disjunctive, and the words "comprising", "containing", "including", "having", etc. shall mean "including but not limited to". Additionally, approximate words such as "about", "almost", "substantially", "generally", "approximately", etc. may be used herein in the sense of "being at, close to, or almost at" or "within 0 - 5% of" or "within acceptable manufacturing tolerances" or a logical combination thereof. As used herein, a component "configured to" perform a specified function is capable of performing the specified function without change, rather than merely having the potential to perform the specified function after further modification. In other words, the described hardware is specifically selected, created, implemented, utilized, programmed, and / or designed for the purpose of performing the specified function when it is explicitly configured to perform the specified function.

[0053] Embodiments of the present disclosure may be described herein in terms of functional and / or logical block components and various processing steps. It should be appreciated that such block components may be implemented by a plurality of hardware, software, and / or firmware components configured to perform the specified functions. For example, embodiments of the present disclosure may employ various integrated circuit components, such as memory elements, digital signal processing elements, logic elements, look-up tables, etc., which may perform various functions under the control of one or more microprocessors or other control devices. Additionally, those skilled in the art will appreciate that embodiments of the present disclosure may be practiced in conjunction with multiple systems, and the systems described herein are merely exemplary embodiments of the present disclosure.

[0054] For the sake of brevity, techniques related to signal processing, data fusion, signaling, control, and other functional aspects of the system (as well as individual operating components of the system) may not be described in detail herein. Additionally, the connecting lines shown in the various figures included herein are intended to represent example functional relationships and / or physical couplings between various elements. It should be noted that alternative or additional functional relationships or physical connections may exist in embodiments of the present disclosure.

[0055] Reference Figure 1, vehicle 10 generally includes a chassis 12, a body 14, front wheels, and rear wheels 17. The body 14 is disposed on the chassis 12 and substantially encloses the components of the vehicle 10. The body 14 and the chassis 12 may jointly form a frame. The wheels 17 are each rotatably coupled to the chassis 12 near a respective corner of the body 14.

[0056] In various embodiments, vehicle 10 may be an autonomous vehicle. Vehicle 10 is, for example, a vehicle that is autonomously controlled to transport passengers from one location to another. In the illustrated embodiment, vehicle 10 is depicted as a pickup truck, but it should be appreciated that other vehicles may also be used, including sport utility vehicles (SUVs), recreational vehicles (RVs), etc.

[0057] Vehicle 10 is part of a vehicle system 9. Vehicle system 9 further includes a trailer 11 attached to vehicle 10. Trailer 11 includes one or more trailer axles 13, each trailer axle having trailer wheels 15 for supporting trailer 11.

[0058] As shown, vehicle 10 generally includes a propulsion system 20, a transmission system 22, a steering system 24, a braking system 26, a sensor system 28, an actuator system 30, at least one data storage device 32, at least one controller 34, and a communication system 36. In various embodiments, propulsion system 20 may include an electric motor, such as a traction motor and / or a fuel cell propulsion system. Vehicle 10 further includes a battery (or battery pack) 21 electrically connected to propulsion system 20. Thus, battery pack 21 is configured to store electrical energy and provide electrical energy to propulsion system 20. Additionally, propulsion system 20 may include an internal combustion engine. Transmission system 22 is configured to transfer power from propulsion system 20 to vehicle wheels 17 according to selectable speed ratios. According to various embodiments, transmission system 22 may include a step-ratio automatic transmission, a continuously variable transmission, or other suitable transmissions. Braking system 26 is configured to provide braking torque to vehicle wheels 17. In various embodiments, braking system 26 may include friction brakes, brake-by-wire systems, regenerative braking systems such as electric motors, and / or other suitable braking systems. Steering system 24 affects the position of vehicle wheels 17. Although for illustrative purposes, steering system 24 is depicted as including a steering wheel, in some embodiments contemplated within the scope of the present disclosure, steering system 24 may not include a steering wheel.

[0059] The vehicle wheel 17 is supported by a front axle 19F and a rear axle 19R. The front axle 19F and the rear axle 19R are separated by a distance D1, and the rear axle 19R is separated from the front axle on the trailer 11 by a distance D2, and the front trailer axle and the rear trailer axle 13 are separated by a distance D3.

[0060] The sensor system 28 includes one or more sensors 40 (i.e., sensing devices) that sense observable conditions of the external and / or internal environment of the vehicle 10. The sensors 40 communicate with the controller 34 and can include, but are not limited to, one or more radars, one or more light detection and ranging (lidar) sensors, one or more ground penetrating radar (GPR) sensors, one or more global positioning system (GPS) devices, one or more cameras (e.g., optical cameras and / or thermal cameras, such as rear cameras and / or front cameras), brake pedal position sensors, accelerator pedal position sensors, steering angle sensors, speed sensors, wheel speed sensors, ride height sensors, steering angle sensors, ultrasonic sensors, one or more inertial measurement units (IMU), trailer connection status sensors, and / or other sensors. The trailer connection status sensor can determine the status of the trailer connection 31 (such as an electrical connection) between the vehicle 10 and the trailer 9. The status of the trailer connection 31 can be used to determine the presence of the trailer 9.

[0061] The sensor system 28 includes one or more global positioning system (GPS) transceivers that are configured to detect and monitor route data (i.e., route information). The GPS device is configured to communicate with GPS to locate the position of the vehicle 10 on the earth. The GPS device is in electronic communication with the controller 34. Since the sensor system 28 provides data to the controller 34, the sensor system 28 and its sensors 40 are considered information sources (or simply sources).

[0062] The actuator system 30 includes one or more actuator devices 42 that control one or more vehicle features, such as but not limited to the propulsion system 20, the transmission system 22, the steering system 24, and the braking system 26. In various embodiments, the vehicle features can further include internal and / or external vehicle features, such as but not limited to doors, trunks, and cockpit features, such as air, music, lighting, etc. (unnumbered). For example, the actuator devices 42 include accelerator pedals, brake pedals, etc.

[0063] The controller 34 includes at least one processor 44 and a non-transitory computer-readable storage device or medium 46. The processor 44 can be a custom or commercially available processor, a central processing unit (CPU), a graphics processing unit (GPU), an auxiliary processor among several processors associated with the controller 34, a semiconductor-based microprocessor (in the form of a microchip or chipset), a microcontroller, a combination thereof, or generally a device for executing instructions. The computer-readable storage device or medium 46 can include, for example, volatile and non-volatile storage devices such as read-only memory (ROM), random access memory (RAM), and keep-alive memory (KAM). KAM is a permanent or non-volatile memory that can be used to store various operating variables when the processor 44 is powered down. The computer-readable storage device or medium 46 can be implemented using multiple other memory devices such as PROM (programmable read-only memory), EPROM (electrical PROM), EEPROM (electrically erasable PROM), flash memory, or other electrical, magnetic, optical, or combination memory devices capable of storing data, some of which represents executable instructions used by the controller 34 in controlling the vehicle 10.

[0064] The instructions can include one or more separate programs, each program including an ordered list of executable instructions for implementing a logical function. When executed by the processor 44, these instructions receive and process signals from the sensor system 28, execute logic, calculations, methods, and / or algorithms for automatically controlling components of the vehicle 10, and generate control signals to the actuator system 30 to automatically control components of the vehicle 10 based on the logic, calculations, methods, and / or algorithms. Although Figure 1 a single controller 34 is shown, embodiments of the vehicle 10 can include multiple controllers 34 that communicate via a suitable communication medium or combination of communication media and cooperate to process sensor signals, execute logic, calculations, methods, and / or algorithms, and generate control signals to automatically control features of the vehicle 10.

[0065] Vehicle 10 includes a human-machine interface (HMI) 23, which can be a central instrument panel screen or a driver information center. The HMI 23 interacts with the user to display information and receive confirmation, activation, cancellation commands, etc. The HMI 23 can be configured as an alarm, such as a speaker for providing sound, a haptic feedback in a vehicle seat or other object, a visual display, or other devices suitable for providing notifications to the vehicle operator of the vehicle 10. The HMI 23 communicates electronically with the controller 34 and is configured to receive input from a user (such as the vehicle operator). Therefore, the controller 34 is configured to receive input from the user via the HMI 23. The HMI 23 includes a display configured to display information to the user (such as the vehicle operator or passenger), and may include one or more speakers for providing audible notifications to the vehicle operator.

[0066] Figure 2 A flowchart of a method 100 for determining the trailer axle count and position relative to the vehicle 10 is illustrated. At block 102, the method 100 receives vehicle operating characteristics and signals from sensors 40 on the vehicle 10. In one example, the vehicle operating characteristics are transmitted as CAN messages over a controller area network (CAN) bus. The CAN messages include vehicle-specific information, which may include the suspension height at each corner of the vehicle 10, the wheel-to-body displacement, the speed of the vehicle 10, the acceleration of the vehicle 10, the wheel speed sensor signals at each wheel 17, the forces on the axles 19F and 19R, the wheel torque at each wheel 17, the road surface grade, the steering wheel angle of the vehicle 10, the trailer connection status signal to the vehicle 10, the output of the IMU of the vehicle 10, ultrasonic sensor signals, camera signals, lidar signals, radar signals, the relative time of occurrence of the above vehicle-specific information, etc.

[0067] The vehicle operating characteristics from the CAN messages are initially analyzed at block 104 and stored at block 106 in a medium 46 such as on the vehicle 10. At block 110, it is determined whether the vehicle 10 has established an enabling incentive using the vehicle operating characteristics stored at block 106, and at block 108, it is determined whether the vehicle 10 has encountered a bump. A bump can include irregularities in the road surface, such as speed bumps, potholes, or other changes in the road surface.

[0068] At block 108, the method 100 determines whether the vehicle 10 has encountered a bump based on the vehicle operating characteristics from block 102 stored at block 106. In one example, the method 100 determines whether the vehicle 10 has encountered a bump by monitoring changes in the ride height of the front and rear axles of the vehicle 10 using ride height sensors. However, the method 100 can utilize other vehicle operating characteristics from the sensors 40, or multiple vehicle operating characteristics, to act as verification for bump detection.

[0069] Figure 3 is a graphical representation 200 of the vehicle ride height captured by at least one of the ride height sensors that are part of the sensor system 28. In the illustrated example, the graphical representation 200 defines time (t) along the x-axis and the vehicle ride height 202 along the y-axis, where line 204 represents the change in the vehicle ride height over time (t). In the illustrated example, the change in the vehicle ride height is measured for a single rear wheel 17; however, the change in the vehicle ride height can also be measured for one or more of the other wheels 17 on the vehicle 10. In the illustrated example, line 204 includes a plurality of spikes 206, and the spikes 206 represent a change in the direction of deflection corresponding to the time (t). The magnified region 210 identifies a possible region that represents the trailer 11 encountering a bump and the force being transmitted to the vehicle 10 through the hitch assembly 29.

[0070] As an alternative to measuring the vehicle ride height, the graphical representation 200 can include information from sensors 40 such as wheel speed sensors, one of the IMUs, ultrasonic sensors, cameras, lidar, or information from another sensor 40 on the vehicle 10 that is capable of capturing the encounter of the vehicle 10 with a bump and the interaction between the trailer 11 and the vehicle 10 when the trailer 11 encounters a bump.

[0071] Figure 4A is Figure 3 a graphical representation 300 of the derivative of the vehicle ride height as shown in. The derivative represents the rate of change of the vehicle ride height. The graphical representation 300 defines time (t) along the x-axis and the rate of change 302 of the vehicle ride height along the y-axis using line 304. In the illustrated example, the rate of change represented by the initial spike 306 can indicate the rate of change of the vehicle ride height corresponding to encountering a bump.

[0072] Figure 4A The magnified region 310 in represents a period of time (t) during which the vehicle ride height sensor captured the interaction where the trailer 11 encountered a bump and transmitted that encounter to the vehicle 10 through the hitch assembly 29. Although Figure 1 the hitch assembly 29 in the illustrated example of is shown as a bumper hitch connection, other hitch connections such as a fifth wheel connection or a goose neck connection can be used in the context of the present disclosure.

[0073] To establish an enabling excitation for a vehicle, method 100 analyzes a set of vehicle operating characteristics from sensor 40. The enabling excitation ensures that vehicle 10 operates in a manner that will reduce errors in calculations configured to determine trailer axle counts and positions, as outlined below. In particular, the enabling excitation can ensure that vehicle 10 and trailer 11 do not move laterally, and that the hitch angle between vehicle 10 and trailer 11 is zero or within a predetermined range including zero or close to zero. In one example, the enabling excitation for vehicle 10 can include at least one of the following: yaw acceleration less than a predetermined threshold, wheel speed difference between the left and right wheels 17 on common axis 19 within a predetermined threshold range, steering wheel angle less than a predetermined threshold, or speed greater than a predetermined threshold to ensure sufficient excitation of the system in the presence of road obstacles (such as bumps). The speed measured by sensor 40 can also vary.

[0074] Once method 100 has determined at block 108 that a bump has been detected and confirmed at block 110 that vehicle 10 has established an enabling excitation, method 100 proceeds to block 112 to perform further analysis of the vehicle operating characteristics. In the illustrated example, a time-based magnitude-phase form is applied to Figure 4A the rate of change of the vehicle ride height shown in, to generate a magnitude based on the rate of change using Equation 1 below (such as Fourier series analysis). Additionally, other time-based methods, such as autocorrelation of the vehicle ride height itself or cross-correlation with another signal, can be used to identify the time position of the interaction of the trailer with the bump relative to the interaction of the vehicle with the bump, thereby estimating the trailer axle position.

[0075]

[0076] Figure 4B is a graphical representation 400 of the Fourier series magnitude-phase form applied to the rate of change from Figure 4A . The graphical representation is shown along the x-axis over time (t), where the output 402 is represented along the y-axis. The enlarged view 410 illustrates the maximum magnitude 406 of line 404. By considering the frequency and wavelength, the position of each axle 13 can be extracted at block 114.

[0077] At block 114, method 100 utilizes a vehicle longitudinal model, such as the model shown in Equation 2 below, to determine the position of each trailer axle 13.

[0078]

[0079] In Equation 2, Z is the output signal, and φ is the regression signal. Method 100 performs the estimation method by executing the recursive least squares method shown in Equations 3 - 5 below.

[0080] P k+1 = (1 - K k+1 φ k+1 )p k / λ Equation 5.

[0081] Method 100 can then output the trailer axle position by analyzing the relative time difference between when the vehicle 10 encounters a bump and when the trailer 11 encounters a bump, as shown in the graphical representation 450. The time (t) of the graphical representation 450 is represented along the x-axis, and the trailer axle length 454 is presented along the y-axis. In the illustrated example, the trailer axle length is relative to the position on the vehicle 10, and the position of a single axle 13 is illustrated. However, method 100 can be used to determine the positions of multiple axles 13. Line 456 represents the actual trailer axle length relative to the vehicle 10, and line 458 represents the estimated trailer axle length relative to the vehicle 10 based on the above method 100. As shown in Figure 5 depending on the particular axle to be located and the relative position on the vehicle 10, the trailer axle length can be represented as a combination of lengths D1, D2, or D3. Figure 1

[0082] One feature for determining the position of the axles on the trailer 9 relative to the vehicle 10 is the positive identification of the trailer 9 coupled to the vehicle 10. Thus, method 100 can operate independently of the controller 34 to determine the presence of the trailer 9 through the trailer connection 31. Thus, in the case of a fault in the trailer connection 31, method 100 provides a redundant confirmation of the presence of the trailer 9 coupled to the vehicle 10.

[0083] Figure 6 Another flowchart of a method 600 for determining the trailer axle count and the position relative to the vehicle 10 is illustrated. In the illustrated example, method 600 receives the left front wheel speed V x FL and the right front wheel speed V x FR at block 602, and determines whether the acceleration of either front wheel exceeds a predetermined threshold acceleration. Similarly, method 600 receives the left rear wheel speed V x RL and the right rear wheel speed V x RR at block 604, and determines whether the acceleration of either rear wheel exceeds a predetermined threshold acceleration. If either front wheel experiences an acceleration that exceeds the predetermined threshold acceleration, method 600 proceeds to block 608.

[0084] At block 608, method 600 performs bump detection. When the acceleration of either front wheel exceeds a predetermined threshold, as determined at block 602, the start of velocity integration is triggered at block 610. Figure 7 Illustrated is a graphical representation 700 that has a line 706 of the longitudinal acceleration a along the y-axis 704 of one or both front wheels on vehicle 10 over a period of time (t) along the x-axis 702. x As Figure 7 shown by the time window 708 in , at least one front wheel of vehicle 10 has encountered a bump on the road sufficient to trigger velocity integration at block 612.

[0085] When the acceleration of one or both rear wheels exceeds a predetermined threshold acceleration, velocity integration stops at block 614. Figure 8 Illustrated is a graphical representation 720 that has a line 726 of the longitudinal acceleration a along the y-axis 724 of one or both rear wheels on vehicle 10 over a period of time (t) along the x-axis 722. x As Figure 8 shown by the time window 728 in , at least one rear wheel of vehicle 10 has encountered a bump on the road sufficient to stop velocity integration at block 614. When velocity integration has stopped, block 610 outputs the estimated wheelbase length WB est which is used for bump verification at block 616. est

[0086] The bump verification performed at block 616 compares the estimated wheelbase length WBest with the wheelbase calibration value from block 606. The wheelbase calibration value represents the measured or predetermined wheelbase length of vehicle 10. If the estimated wheelbase length WB est is within a predetermined range or percentage of the wheelbase calibration value, such as a difference less than or equal to 5%, then method 600 has determined that vehicle 10 has encountered a bump and proceeds to block 620. If the estimated length WB est is not within the predetermined range or percentage, then method 600 proceeds to block 618 and stops determining the trailer axle count and position because the wheelbase comparison did not confirm that vehicle 10 has encountered a bump.

[0087] At block 620, method 600 starts determining the trailer axle count and position relative to the towing vehicle 10 by starting additional velocity integration at block 634. The start of velocity integration at block 634 is coincident with the time when block 622 determines that one of the rear wheels of vehicle 10 has experienced a sudden acceleration exceeding a predetermined threshold acceleration.

[0088] Once the speed integration begins at block 636, method 600 begins determining the axle count and position relative to vehicle 10 at blocks 638 and 640. Block 638 receives additional information about vehicle 9 from block 624 from at least one of the sensors 40 on vehicle 9, such as an IMU. In the illustrated example, this additional vehicle-related information includes the longitudinal jerk of the vehicle at block 626 the yaw acceleration of vehicle 9 at block 628 and the pitch acceleration of vehicle 9 at block 630 If the longitudinal jerk the yaw acceleration or the pitch acceleration of at least one of them exceeds a corresponding predetermined threshold acceleration, block 624 sends an indication to block 638 that at least one axle 13 on trailer 11 has encountered a bump. Figure 9 Illustrated is a graphical representation 740 of the longitudinal jerk of vehicle 9 utilized by block 626 In the illustrated example, the graphical representation 740 includes time (t) along the x-axis 742 and jerk along the y-axis 744 A time window 748 including line 746 represents when trailer 9 has encountered a bump.

[0089] Block 638 may record the corresponding time of encountering the bump. If trailer 11 continues to encounter any of the above accelerations / jerks exceeding the corresponding thresholds, method 600 may indicate that trailer 11 has multiple axles and that subsequent axles 13 on trailer 11 have encountered a bump.

[0090] Figure 10 is a graphical representation 800 that utilizes line 806 to identify the trailer axles, and this graphical representation 800 has relative time (t) along the x-axis 802 and the number of axles identified along the y-axis 804. In Figure 10 the illustrated example, each step in line 806 indicates the relative time when block 624 identifies that trailer 11 has encountered one of the accelerations exceeding a predetermined threshold.

[0091] In addition, Figure 11 is a graphical representation 850 that utilizes lines 856 and 858 to identify the longitudinal position of axle 13, and this graphical representation 850 has relative time (t) along the x-axis 852 and the longitudinal position along the y-axis 854. Line 856 represents the first relative time when the speed integration identifies the position of the first axle 13, and line 858 represents the second relative time when the speed integration identifies the position of the second axle 13. Lines 860 and 862 correspond to the actual position of axle 13 compared to the estimated position of the axle.

[0092] Method 600 further analyzes the longitudinal jerk at block 632 Yaw acceleration or pitch acceleration to identify a decrease in the oscillation amplitude. A decrease in the oscillation amplitude in at least one of the longitudinal jerk yaw acceleration or pitch acceleration may indicate that there is no additional axle to be identified on the trailer 11, and the velocity integration from block 638 should stop. Then, block 620 may output the trailer axle count and position based on the relative time at which at least one of the longitudinal jerk yaw acceleration or pitch acceleration exceeds a corresponding predetermined threshold and the relative time of the decrease in the magnitude of one of the acceleration / jerk. Longitudinal jerk is the derivative of the acceleration of the vehicle 9.

[0093] Using the trailer axle count and position determined by the above method 100 or method 600, this information can be used as an input to automatically adjust an automatic trailer brake gain modifier. Additionally, when multiple axles are identified, an estimate of the effective wheelbase of the trailer can be made based on the average of each position of the axle relative to the vehicle 10.

[0094] Furthermore, methods 100 and 600 can continuously recalculate the trailer axle count and position to determine a change in the operating state of the trailer 11. For example, if methods 100 or 600 determine that a change in the axle count or position exceeds a predetermined threshold, then methods 100 and 600 can determine that the state of the trailer 11 has changed. For example, a change in state may indicate that the primary coupling between the vehicle 10 and the trailer 11 has become detached or that the attachment requires further adjustment, such as changing the attachment height of the vehicle 10 to level the trailer 11.

[0095] The terms “a” and “an” do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items. The term “or” means “and / or” unless the context clearly dictates otherwise. References throughout the specification to “one aspect” mean that a particular element (e.g., a feature, a structure, a step, or a property) described in connection with that aspect is included in at least one aspect described herein and may or may not be present in other aspects. Additionally, it is to be understood that the described elements may be combined in various aspects in a suitable manner.

[0096] When an element such as a layer, a film, a region, or a substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly” on another element, no intervening elements are present.

[0097] Unless otherwise specified herein, the test standards are the latest standards effective as of the filing date of the present application, or, if priority is claimed, the latest standards effective as of the filing date of the earliest priority application in which the test standards appear.

[0098] Unless otherwise defined, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0099] Although the foregoing disclosure has been described with reference to exemplary embodiments, those skilled in the art will understand that various changes can be made and elements thereof can be replaced with equivalents without departing from the scope of the disclosure. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the disclosure without departing from its scope. Therefore, it is intended that the disclosure not be limited to the particular embodiments disclosed, but will include embodiments falling within its scope.

Claims

1. A method for determining trailer axle count and the position of a trailer's axles relative to a vehicle, the method comprising: Receiving a plurality of vehicle operating characteristics from at least one sensor on the vehicle; Determining whether the vehicle has encountered a bump on the road based on at least one of the plurality of vehicle operating characteristics; Determining whether at least one trailer axle has encountered the bump; And Analyzing the relative time difference between when the vehicle encounters the bump and when the at least one trailer axle encounters the bump to determine the trailer axle count and estimate the position of the at least one trailer axle relative to the vehicle.

2. The method according to claim 1, including determining an enabling excitation of the vehicle when the vehicle encounters the bump, wherein determining the enabling excitation includes identifying at least one of the following: the steering angle of the vehicle is within a predetermined range, the speed of the vehicle is greater than a predetermined speed, or the wheel speed difference between laterally spaced wheels on the vehicle is less than a predetermined value.

3. The method according to claim 1, including confirming the presence of a trailer coupled to the vehicle when the position of the at least one trailer axle relative to the vehicle is estimated.

4. The method according to claim 1, wherein the at least one sensor includes at least one of a ride height sensor, a wheel speed sensor, or an inertial measurement unit located on the vehicle, and determining whether the vehicle has encountered the bump is based on determining the magnitude of the rate of change of at least one of the plurality of vehicle operating characteristics.

5. The method according to claim 1, wherein the at least one sensor is located on the vehicle, and determining whether the at least one trailer axle has encountered the bump is based on determining the magnitude of the rate of change of at least one of the plurality of vehicle operating characteristics within a time range after the vehicle has encountered the bump.

6. The method according to claim 5, including determining the state of the trailer by determining whether the magnitude of the rate of change of the at least one vehicle operating characteristic is within a predetermined range.

7. The method according to claim 1, including: Receiving a second plurality of vehicle operating characteristics from the at least one sensor on the vehicle; Determining whether the vehicle has encountered a second bump on the road based on at least one of the second plurality of vehicle operating characteristics; Determining whether at least one trailer axle has encountered the bump; Analyzing the relative time difference between when the vehicle encounters the bump and when the at least one trailer axle encounters the bump to determine a second trailer axle count and estimate a second position of the at least one trailer axle relative to the vehicle; And Determining a change in the operating state of the trailer if the difference between the second position of the at least one trailer axle and the position of the at least one trailer axle exceeds a predetermined threshold.

8. The method according to claim 1, wherein determining whether the vehicle has encountered the bump includes determining an estimated wheelbase length of the vehicle based on the speed of the vehicle and the relative time difference between when the front wheels of the vehicle encounter the bump and when the rear wheels of the vehicle encounter the bump.

9. The method according to claim 8, wherein if the estimated wheelbase length is within a predetermined range of a predetermined wheelbase length of the vehicle, the vehicle has encountered the bump.

10. The method according to claim 8, wherein determining the estimated wheelbase length comprises: Integrate the speed of the vehicle starting from when one of the front wheels of a pair of front wheels encounters the bump until one of the rear wheels of a pair of rear wheels encounters the bump.

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