A system for a tow vehicle-trailer combination

Abstract

The present invention relates to a system for a tow vehicle-trailer combination, and a tow ball comprising such a system. The system comprising a sensor arrangement for measuring forces acting on a tow coupling and a computing device for processing data received from the sensor arrangement to determine at least one property of the tow vehicle-trailer combination and transmit at least one control signal to a trailer brake controller to control brakes of the trailer and / or transmit a message to a driver of a tow vehicle.

Description

A system for a tow vehicle-trailer combinationTechnical Field

[0001] The present invention relates to systems for a tow vehicle-trailer combination, and in particular to a system for measuring forces acting on the tow coupling of a tow vehicle-trailer combination.Background of Invention

[0002] Vehicles, such as cars, have limited transport capabilities. If a vehicle needs to carry or transport heavy loads, it may be desirable to connect a trailer to the vehicle.

[0003] A vehicle may be any car, truck, van, crossover, SUV, RV or any other similar automotive vehicle which is used to pull a trailer. When a trailer is connected to a vehicle, the vehicle is usually called a “tow vehicle”. A trailer may be any wheeled construction that is pulled by the tow vehicle. A trailer may be, for instance, a utility trailer, pop-up camper, travel trailer, livestock trailer, flatbed trailer, boat trailer or any other similar trailer. A trailer may also be another vehicle that is being towed by the tow vehicle.

[0004] There are several different components needed for towing any type of trailer to a vehicle. A towing system is usually made up of the vehicle, trailer, and parts which are used to connect them.

[0005] One of the parts used for connecting a trailer and a vehicle is a trailer hitch. A trailer hitch (also known as a tow hitch or tow bar) is a structural component which provides the primary connector between a tow vehicle and a trailer. A trailer hitch usually bolts onto the underside of a vehicle, at the rear, and provides a tube for attaching a ball mount or other tow coupling. The terms trailer hitch, hitch, tow hitch and tow bar may be used interchangeably.

[0006] A trailer / tow coupling is the mechanism by which a trailer is connected to a tow vehicle. A ball mount is a type of trailer coupling which is usually comprised of a shank and a trailer ball platform. A ball mount is one of the most common trailer hitch parts. Ball mounts come in a variety of styles and capacities. Usually, the shank inserts into the hitch receiver tube, while the platform provides a solid mounting point for a trailer ball.

[0007] A trailer ball (i.e. towball / tow ball / ball) is one example of the immediate connection point between a vehicle and a trailer. It is usually made up of a metal ball and a threaded shank or stem. The trailer ball is a part of tow coupling, and thus, among others, allows the driver of the vehicle to turn corners and guide the trailer.

[0008] Undesirably, trailers can sway and / or trailer braking systems may fail. This puts the driver of the tow vehicle and other people in the vicinity of the tow vehicle and the trailer in danger.

[0009] The present applicant has recognized the need for improved trailer safety.Summary of Invention

[0010] We describe apparatuses and systems in the appended claims. Other features of the invention will be apparent from the dependent claims, and the description which follows.

[0011] In one example, there is provided a system for a tow vehicle-trailer combination, the system comprising a sensor arrangement for measuring forces acting on a tow coupling; wherein the sensor arrangement is placed in the tow coupling; a computing device for processing data received from the sensor arrangement; wherein the computing device is configured to: receive data from the sensor arrangement; determine at least one property of the tow vehicle-trailer combination based on the received data from the sensor arrangement; and based on the determined at least one property of the tow vehicle-trailer combination, transmit at least one control signal to a trailer brake controller to control brakes of the trailer and / or transmit a message to a driver of a tow vehicle.

[0012] In one example, the at least one property of the tow vehicle-trailer combination is any one of: trailer braking level property, trailer brake gain property, trailer ABS property, trailer sway property, trailer brake condition property, trailer mass distribution property.

[0013] In one example, the computing device is configured to receive information about a velocity of the tow vehicle from an external source.

[0014] In one example, the trailer braking level property is a rate of adjustment of the amount of force acting on the tow coupling to a target value.

[0015] In one example, the target value is a value which allows the tow vehicle with regenerative braking to recover energy from the trailer during braking.

[0016] In one example, the trailer gain property is the gain of the trailer brake controller.

[0017] In one example, the trailer gain property is used to apply an offset to braking of the trailer brakes to allow energy recovery by the tow vehicle.

[0018] In one example, the trailer ABS property is a decrease in braking output of the trailer brakes if a rate of force with respect to the brake output becomes negative or close to zero.

[0019] In one example, the trailer sway property is sway of the trailer.

[0020] In one example, the computing device is configured to solve differential equations of trailer motion to determine the yaw rate of the trailer and apply sway control if the trailer yaw rate exceeds the tow vehicle yaw rate, independently of tow vehicle characteristics.

[0021] In one example, the trailer brake condition property is a status of brake condition of the trailer.

[0022] In one example, the trailer mass distribution property is a distribution of trailer mass.

[0023] In one example, the computing device is configured to determine separate forces acting on the tow coupling.

[0024] In one example, the computing device is configured to correct data received from the sensor arrangement by temperature compensation and / or linearization.

[0025] In one example, the sensor arrangement is configured to measure forces acting on the tow coupling along X, Y, and Z axes.

[0026] In one example, the sensor arrangement further comprises at least one inertial sensor.

[0027] In one example, the sensor arrangement further comprises a near-fieldcommunication, NFC, energy harvesting device and NFC exciter.

[0028] In one example, the sensor arrangement further comprises a magnetic field sensor, a magnetized pin and magnetic concentrator.

[0029] In one example, the tow coupling is a tow ball. In another example, the tow coupling is the mating coupling for the tow ball or a similar hitch.

[0030] In one example, the sensor arrangement is placed coaxially in a bore of the tow ball.

[0031] In one example, the sensor arrangement comprises: at least one pin, wherein each one of the at least one pin is fixed to one portion of the tow coupling and passing through a neck of the tow coupling via a clearance hole; and at least one sensor embedded in a spacer foot of the tow coupling.

[0032] In one example, the system further comprises the trailer brake controller.

[0033] There is also provided a tow ball comprising: the system of any one of the above- mentioned examples.

[0034] There is also provided a tow ball comprising: a sensor arrangement which is configured to measure forces acting on the tow ball in at least one and up to three dimensions along X, Y and Z axis of the tow ball; wherein the sensor arrangement is configured to transmit the measured forces to a computing device; wherein the sensor arrangement is placed in the tow ball.

[0035] In one example, the tow coupling is on the vehicle or the trailer.

[0036] In one example, the trailer ABS property is a decrease in braking of at least one trailer brake if a rate of force with respect to the at least one brake output becomes negative or close to zero.

[0037] In one example, the trailer brake condition property is a performance measure of at least one trailer brake actuator.

[0038] In one example, the trailer mass distribution property includes at least one of trailer total mass, trailer yaw moment of inertia or trailer ball weight.

[0039] In one example, the system applies an offset to braking of the trailer brakes to allow energy recovery by the tow vehicle while remaining within a limit. The limit may be a force limit. The limit may modify the braking of the trailer to emulate the force applied by an unbraked trailer of a specified weight.

[0040] In one example, the sensor arrangement further comprises one or more strain gauges contained within the coupling assembly.

[0041] In one example, the tow coupling comprises: a trailer coupling body to be installed on a trailer drawbar; a spacer attaching to the trailer drawbar; and the sensor arrangement is attached to the coupling body or the spacer. The sensor arrangement may be using inductive, strain or magnetic sensors attached to the coupling body or the spacer.Brief Description of Drawings

[0042] Implementations of the present techniques will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0043] Figure 1 shows a schematic overview of a system of the present techniques;

[0044] Figure 2a shows a top view of a first force sensor arrangement according to the present techniques;

[0045] Figure 2b shows a cross-sectional side view of the first sensor arrangement of the present techniques;

[0046] Figure 2c shows a detail view of the internal components of the first sensor arrangement of the present techniques;

[0047] Figure 2d shows a plan view of an exemplary printed circuit board;

[0048] Figure 3a shows a perspective view of a second force sensor arrangement according to the present techniques;

[0049] Figure 3b shows a cross-sectional side view of the second sensor arrangement of the present techniques;

[0050] Figure 3c shows a side view of the second sensor arrangement of the present techniques;

[0051] Figure 4a shows a perspective view of the third force sensor arrangement according to the present techniques;

[0052] Figure 4b shows a cross-sectional side view of the third sensor arrangement of the present techniques;

[0053] Figure 4c shows a side view of the third sensor arrangement of the present techniques;

[0054] Figure 5 shows a diagram overview of methods for processing sensor data of the sensor arrangements and methods for improving trailer safety;

[0055] Figure 6 shows a flowchart of the method of the present techniques for processing sensor data of the sensor arrangement;

[0056] Figure 7 shows a flowchart of the method for increasing towing safety;

[0057] Figure 8 shows an exemplary direct brake control block diagram;

[0058] Figure 9 shows an exemplary block diagram for controlling gain;

[0059] Figure 10a shows a perspective view of a connector for the sensor arrangement;

[0060] Figure 10b shows a cross-sectional side view of a connector for the sensor arrangement;

[0061] Figure 10c shows a side view of a connector for the sensor arrangement; and

[0062] Figure 11 shows an exemplary diagram of a brake controller output;

[0063] Figure 12a shows an isometric view of an alternative sensor arrangement, mounted in the coupling body of a trailer;

[0064] Figure 12b shows a side view of the alternative sensor arrangement of Figure 12a;

[0065] Figure 13a shows an isometric view of another alternative sensor arrangement, mounted in the coupling body of a trailer;

[0066] Figure 13b shows a side view of the sensor of Figure 13a;

[0067] Figure 14 shows an isometric view of another alternative sensor arrangement, mounted in an extension to the coupling body of a trailer;

[0068] Figure 15 shows an isometric view of another alternative sensor arrangement, mounted in the coupling body of a trailer; and

[0069] Figure 16 shows the structure of a printed strain gauge.Detailed Description

[0070] Broadly speaking, the present techniques relate to a system which comprises trailer force sensor / sensor arrangement incorporated in a tow coupling, used for improving trailer safety. This is achieved by using a force gauge incorporated in a tow coupling to measure the strain or the bending of the coupling. Strain gauges are able to detect slight changes in the length of the object they are attached to. If a trailer is travelling faster than the vehicle towing it, the trailer will push the tow ball forward. If the trailer is travelling slower than the tow vehicle, the trailer will pull the tow ball backwards. This force will apply pressure to the tow ball. This pressure should slightly stretch the metal in the tow ball, which would be detected by a strain gauge. Beneficially, the direction of strain will inform the system of the present techniques to either apply or release the brakes of the trailer. Multiple gauges can be used to detect strain along multiple axes. If trailer weight is improperly distributed, the strain on the tow ball would either be upwards or too heavily downwards. A swaying trailer would also apply strain to the sides of the tow ball. As such, the firmware could be calibrated to detect or mitigate these issues.

[0071] A magnetic sensor can detect the presence, strength and location of a magnetic field through the Hall Effect or magnetostrictive effect. A sensor attached to the base of the trailer towball will detect the magnetic field from the head of the tow ball, and the strength and orientation of this field can be used to determine the distance from the sensor as the tow ball bends under force. This should result in the twisting and hence the force exerted by the trailer on the tow-ball being estimated in at least two dimensions. Thus, beneficially, the systems and methods of the present techniques may provide the technical advantages described below.

[0072] The system of present techniques may beneficially provide a measurement of trailer mass / kinematic parameters for safety. These parameters include trailer ball mass and / or total trailer mass. Potentially, in certain examples, the present techniques may measure trailer yaw moment of inertia.

[0073] The system of present techniques may also beneficially provide a measurement of trailer lateral force and / or articulation angle, and thus allow for correction of trailer sway.

[0074] The system of present techniques may beneficially provide a measurement of trailer longitudinal force. Measurement of trailer longitudinal force allows calibration of brake gain and / or closed-loop control of trailer braking and / or closed-loop control of trailer braking with trailer mass compensation. Thus, beneficially, the tow vehicles’ EV range (i.e. the distance a car can travel on a single charge) can be improved.

[0075] Beneficially, combined lateral and longitudinal measurements of trailer longitudinal force in combination with knowledge of trailer braking level allow for the detection of wear or mis-adjustment of trailer brakes and / or trailer ABS without a wheel speed sensor.

[0076] The system of present techniques may also beneficially provide improved sensor arrangement cost and lifetime. These technical advantages may arise as a consequence of calibration methods that allow for use of non-linear sensors and / or mechanical protections that arise from incorporating the force sensor arrangement in the tow coupling.

[0077] The features which are the same or substantially similar may retain the same reference numbers in the Figures and throughout the description. Therefore, a repeated description of such features may be omitted.

[0078] All examples of the present techniques may be combined together, unless it is explicitly stated otherwise.System Overview

[0079] Figure 1 shows a schematic overview of a system 1000 for a trailer. Beneficially, as described in more detail below, the system 1000 improves trailer safety.

[0080] The system 1000 comprises a sensor arrangement 1002 and a computing device 1004. Optionally, the system 1000 comprises a trailer brake controller 1006 and / or a second computing device 1008.

[0081] The sensor arrangement 1002 is in communication with the computing device 1004. The computing device 1004 may be communication with a trailer brake controller 1006. The computing device 1004 may be also in communication with a second computing device. The communication may be via one or more of the internet, Bluetooth, NFC, and / or wired communication and / or similar communication techniques known in the art. The computing device 1004 may also be the processing means of the trailer brake controller 1006 or the vehicle trailer brake controller (not shown).

[0082] The sensor arrangement 1002 may be any one of the example sensor arrangements 100,200,300 described in relation to Figures 2, 3 and 4 and 12 to 15.

[0083] The computing device 1004 may be any suitable electronic device, e.g. a personal computer or computing device, a laptop, a car computer, a tablet, a smart phone etc. It will be understood that this is a non-exhaustive and non-limiting list of example devices. In the simplest implementation, the computing device 1004 comprises at least one processor coupled to a memory. The at least one processor may comprise one or more of: a microprocessor, a microcontroller, and an integrated circuit. The memory may comprise volatile memory, such as random access memory (RAM), for use as temporary memory, and / or non-volatile memory such as Flash, read only memory (ROM), or electrically erasable programmable ROM (EEPROM), for storing data, programs, or instructions, for example. The computing device may comprise at least one user interface.

[0084] The skilled person will appreciate that the computing device 1004 may be part of the sensor arrangement. Thus, the sensor arrangement may comprise the computing device 1004. For example, the sensor arrangement may incorporate a Bluetooth SoC such as nRF52833 to perform both computations and communications. Alternatively, the computing device 1004 may be separate from the sensor arrangement 1002. The computing device 1004 may be built into the towing vehicle (e.g. a module on the towed or towing vehicle or in the towing vehicle computer), or may be present in the towing vehicle (e.g. an app on a smartphone of the driver). The computing device 1004 may be also placed in the towball or the towballconnector or vehicle brake controller or trailer brake controller or in a coupling body of a trailer. In another alternative, the computing device 1004 may be built into the connector that supplies power to the sensor arrangement. This connector is shown in Figures 10a, 10b and 10c.

[0085] The computing device may transmit a control signal to a trailer brake controller to control the brakes of the trailer. Therefore, the trailer brake controller 1006 is configured to control the brakes of the trailer based on the control signal received from the computing device 1004. This would require a trailer brake controller with the ability to accept either direct feedback or a gain control setting via a communications interface. Therefore, the computing device 1004 is configured to communicate with the trailer brake controller 1006. The computing device 1004 may have permission to control the trailer brake controller 1006. The transmission of the control signal is based on at least one property of the trailer-tow vehicle combination. For example, to control brake controllers that are in common use, the computing device 1004 may calculate a gain and offset configuration based on the trailer force measurements. This configuration may be sent via a Bluetooth interface, whereby the brake controller may increase its output at higher gain levels.

[0086] The computing device 1004 may transmit a message to a driver of a tow vehicle. The transmission of the control signal is based on at least one property of the tow vehicle-trailer combination. The message may be transmitted directly from the computing device 1004 (e.g. when the computing device is part of the vehicle dashboard or an application on the driver’s smartphone). Alternatively, the message may be transmitted via a second computing device 1008. The second computing device 1008 is in the possession of the driver of the vehicle and / or a person who manages the tow vehicle (e.g. a company monitoring their fleet). This message may, for example, be used to warn the driver of unsafe loading, or may allow the fleet owner to determine when to perform maintenance on their trailers, or may allow billing based on trailer usage. The message may be in the format of at least one of the following: a text message, multimedia message, voice message, email message, instant message, push notification or any other similar format. The message may be a warning message and / or informative message.

[0087] The system 1000 is configured to implement the method described in relation to Figures 5, 6 and 7.Force Sensor Arrangements

[0088] Figure 2a shows a top view of a force sensor arrangement 100 according to the present techniques. Figure 2b shows a cross-sectional side view of the sensor arrangement 100 of the present techniques. Figure 2c shows a detail view of the internal components of the sensor arrangement 100 of the present techniques. Figure 2d shows a plan view of an exemplary printed circuit board.

[0089] In one example, the force sensor arrangement 100 comprises a magnetised pin 52, a magnetic sensor 57, such as Texas Instruments TMAG3001 , and a magnetic concentrator 56.

[0090] The skilled person will appreciate that the sensor arrangement can comprise one or more magnetised pins 52, one or more magnetic sensors 57 and one or more concentrators 56. The magnetic sensor 57 may be placed on a printed circuit board 53.

[0091] The force sensor arrangement 100 may be placed within a tow ball 50 of a tow coupling 51 between a vehicle and a trailer. The skilled person will appreciate that the tow coupling 51 does not have to comprise necessarily a tow ball 50, and the force sensor arrangement 100 may be placed into any tow coupling 51 that connects the tow vehicle and its trailer. For instance, the tow coupling 51 may be a towbar, a trailer drawbar or a DO35 / DO45 style hitch. In the examples below, the tow coupling 51 is a tow ball 50. The tow ball 50 comprises a mounting shaft 153. The mounting shaft 153 may be used for mounting the tow ball 50 on the hitch.

[0092] The skilled person will appreciate that sensor arrangement 100 may be inserted into the tow coupling 51 during manufacturing. Alternatively, the skilled person will appreciate that the sensor arrangement 100 may be retrofitted into the tow coupling which is similar to the described ball 50 of the tow coupling 51 .

[0093] The tow coupling 51 comprises an axial bore 120 reaching from the base of the tow coupling 51 to the towball 50. The towball 50 may have an opening 140 for the magnetised pin 52. The sensor arrangement 100 may be inserted, into the ball opening 140 and thus into the tow coupling 51 . The opening may be sealed after the magnetised pin 52 is inserted into the tow coupling 51. The sealing may be permanent. In other words, the magnetised pin 52 may be inserted coaxially into the shaft of the axial bore 120, with the magnetic sensor 57 on a printed circuit board 57 and the magnetic flux concentrator 56 being inserted from the other end of the bore. This may be done during the manufacturing of the tow ball. Alternatively, the sensor arrangement may be retrofitted into the tow ball.

[0094] In one example, the force sensor arrangement 100 comprises the magnetised pin 52 fixed to a positioning fastener 49 that is fastened to the head of the tow ball 50, a magnetic sensor 57 and a magnetic concentrator 56. Both the magnetic sensor 57 and the magnetic concentrator 56 are fixed relative to the mounting shaft 153 of the tow ball 50 by a positioning component 55, and not directly coupled to the head of the tow ball 50. Due to the very small movements involved, it is advantageous that the positioning component 55 has a coefficient of thermal expansion closely matched to the material of the towball neck 151 , and is fixed to the same surface as the magnetic concentrator 56.

[0095] The magnetic flux concentrator 56 is a piece of ferrous material, such as steel, that is used to direct or intensify magnetic flux towards at least one sensing element, which in this example, is at least one magnetic sensor 57. It is desirable that the concentrator 56 is constructed from an ultra-low coercivity material such as Permalloy or Mu-metal. The magnetic flux concentrator 56 is required to have sharp points near the magnetic sensor 57. This dB beneficially increases the variation of the magnetic field with the magnetised pin 52 position so that it is easier and more efficient for the magnetic sensor(s) 57 to measure the variation of the magnetic field produced by the magnetised pin 52.

[0096] The magnetic sensor 57 detects the movement of the magnetised pin 52 relative to the concentrator 56. In other words, the magnetised pin 52 approaching the sensor(s) 57 changes magnetic flux and thus generates a magnetic field that is measured by the magnetic sensor 57. The position of the magnetised pin 52, relative to the at least one magnetic concentrator 56 may be measured by the magnetic sensor 57 (using both the magnitude and direction of the magnetic field). Effectively, as the pin 52 moves towards one point of the concentrator 56, the flux of the magnetised pin 52 will be directed preferentially to that point, and less to the other points. Since the (at least one) sensor 57 is measuring the direction and intensity of the flux in the gap between the pin 52 and the concentrator 56, the change in concentration and direction can be detected by at least one sensor 57. This will beneficially give a reading of the angle of bending over the tow coupling neck 151 .

[0097] It is beneficial when the magnetic sensor 57 is a triaxial magnetic sensor. Tri-axis (triaxial) magnetic sensors are directionally independent which means that they are capable of detecting magnetic fields coming from any direction. The benefit of using triaxial magnetic sensor 57 is that the triaxial sensor can simultaneously detect three-dimensional magnetic fields along the X, Y, and Z axes. Consequently, the result obtained from the triaxial sensor can be separated into the components of lateral, longitudinal and axial force, coming from the trailer coupling 51. Sensing magnetic force along two axes is sufficient to measure lateral and longitudinal forces acting on the trailer coupling 51. One axis is sufficient to measurelongitudinal forces, but only if sensor arrangement 100 is installed with the sensing axis aligned with the forward direction.

[0098] The force sensor arrangement 100 may further comprise a PCB 53. The PCB 53 may be included in the base of mounting shaft 153 of the tow coupling 51. The PCB may comprise the magnetic sensor 57 and / or a communications module 54. The force sensor arrangement 100 may further comprise connectors 154 and O-rings 155 to seal the assembly from moisture. Figure 3a shows a perspective view of another force sensor arrangement 200 according to the present techniques. Figure 3b shows a cross-sectional side view of the sensor arrangement 200 of the present techniques. Figure 3c shows a side view of the sensor arrangement 200 of the present techniques.

[0099] In this example, the force sensor arrangement 200 is similar to the sensor 100 arrangement in Figures 2a, 2b and 2c. The main difference is that in this example, the force sensor arrangement 200 comprises at least one strain gauge, instead of the at least one magnetic sensor. Some of the parts of the sensor arrangement 200 are the same or substantially similar to the parts as described in the relation to sensor arrangement 100, therefore, a repeated description of such parts will be omitted. Beneficially, the strain gauge 60 will give a reading of the bending and axial strains in the neck 151 of the shaft of the tow coupling 51. It is desirable to use three strain gauges measuring the bending strain at three locations distributed around the axial bore 120, because three strain gauges enable the separation of the components of lateral, longitudinal, and axial force from the tow coupling 51 . However, the skilled person will appreciate that at least one strain gauge may be used.

[0100] The at least one strain gauge 60 may be adhered to the internal walls of the axial bore 120 of the tow ball 50. Alternatively, at least one strain gauge 60 may be adhered to a coaxial core 90 of the tow ball 50. In this alternative configuration, the coaxial core 90 may be fitted to the axial bore 120, with wiring to the at least one strain gauge 60 passing through flats 92 of the coaxial core 90. The coaxial core 90 may be press-fit, glued or screwed in position.

[0101] Figure 16 shows an exemplary structure of a printed strain gauge. The skilled person will appreciate that at least one strain gauge 60 may also be printed on the wall of the axial bore 120, over a layer of insulator 792. In other words, the sensor arrangement may comprise one or more strain gauges. The sensor arrangement may comprise one or more strain gauges contained within the coupling assembly. The gauge may be printed in carbon or graphene ink 793, and then heat cured to stabilise performance over temperature and product life. The gauge may be further covered with a layer of insulation 794. In such a situation, it is desirable to add a reference resistor with rotational symmetry to act as a reference fortemperature and lifetime changes. The insulator may be printed, or applied by chemical techniques (e.g. parylene or black oxide).

[0102] The force sensor arrangement 200 may further comprise a PCB 64. The PCB 64 may be included in the base of mounting shaft 153 of the tow coupling 51. The PCB may comprise a converter 61 and / or a communications module 63. For instance, the PCB 64 may be used for signal conditioning using e.g. a sigma-delta converter 61 and / or communications module 63. The PCB 64 may be connected to the strain gauges 60 by wires, by spring pins or by conductive adhesives or any other similar means.

[0103] The skilled person will appreciate that sensor arrangement 200 may be inserted into the tow coupling 51 during manufacturing. The tow coupling may comprise a tow ball 50. Alternatively, the skilled person will appreciate that the sensor arrangement 200 may be retrofitted into a ball of a tow coupling which is similar to the described towball 50 of the tow coupling 51.

[0104] The skilled person will also appreciate that similar sensor arrangements may instead be included in the coupling body on the trailer side as shown in Figures 12a, 12b, 13a and 13b. Thus, the tow coupling may be a coupling body of a trailer.

[0105] Figure 12a shows an isometric view of an alternative sensor arrangement, mounted in the coupling body of a trailer. Figure 12b shows a side view of the alternative sensor arrangement of Figure 12a. Figure 13a shows an isometric view of another alternative sensor arrangement, mounted in the coupling body of a trailer. Figure 13b shows a side view of the sensor of Figure 13a. Figure 14 shows an isometric view of another alternative sensor arrangement, mounted in an extension to the coupling body of a trailer. Figure 15 shows an isometric view of another alternative sensor arrangement, mounted in the coupling body of a trailer.

[0106] The at least three strain sensors, instead of being coaxial to the coupling are optimally located between a spacer foot 750 and a standardised coupling body 751 . In this arrangement, at least one gauge 752 is placed on a portion of the assembly that will undergo substantially different strain to at least one other gauge 753. In the example of Figures 12 and 13, these are on a spacer 754 and on the standardised coupling body 751 . As for the towball implementation shown in Figures 2,3 and 4, the sensors may be standard or printed strain gauges, and may be attached by wires or spring pins. In the examples where the tow coupling comprises a coupling body of a trailer, the standardised coupling body 751 attaches to the sensor assembly by bolts through mounting holes 755, with the sensor assembly then attachingto the trailer drawbar using the same pattern of holes 759 with an offset to reduce any distortion of the sensors during installation.

[0107] The skilled person will understand that it may not be possible to read a useful force measurement from any of the gauges individually, and therefore the unmixing step (7) as further described below is critical when the tow coupling is a coupling body of a trailer.

[0108] Inductive sensors such as Texas Instruments LDC1000 may be used to measure eddy currents in targets 793 fixed to the coupling body using printed sensor coils on the surface of a PCB 795. In this implementation, any strains due to the forces will produce extremely small movements causing the targets 793 to move relative to the PCB 795. The movement will be in the order of magnitude of the thermal expansion of the PCB and sensor targets. For this reason, the PCB 795 may be supported by pins 794 of the same material as the spacer 796, and which are fixed by solder or adhesive to the upper surface of the PCB 795. For the same reason, the targets must be shielded from the coupling body by at least one ferrite plate 791 such as a sintered MnZn ferrite that has a coefficient of thermal expansion closely matching the steel parts of the sensor assembly, and fixed to the ferrite 791 by a thin adhesive 792, or even printed onto the surface of the ferrite 791 .

[0109] The skilled person will appreciate that the combination of spacer and foot of equivalent function from figures 12 through 15 may be formed from sheet metal, cast, or assembled from parts, and that alternative coupling bodies may be used.

[0110] It will be appreciated that the sensor arrangements 100, 200, 300 may also be applied in a spacer 785 for a trailer coupling 780. Thus, the tow coupling may be a spacer for a trailer coupling. In this example, the sensor cartridge 783 and magnetic pin 782 may be inserted into at least one drilled portion 787 of a spacer 785 between a trailer coupling body and a trailer drawbar. Due to the leverage of the coupling body and the three related bending moments in the coupling body, it is desirable to use two of these sensors in different angles in order to get reliable measurements, whereas only one is required in the towball. The wiring of these sensor cartridges may be routed to an external communications module or to a brake controller through a sealed connector 784. The mounting holes 786 for the spacer may be identical to those 781 of the standardised coupling body 780 to allow retrofit of the part to existing trailers.

[0111] Figure 4a shows a perspective view of another force sensor arrangement 300 according to the present techniques. Figure 4b shows a cross-sectional side view of the sensor arrangement 300 of the present techniques. Figure 4c shows a side view of the sensor arrangement 300 of the present techniques.

[0112] In this example, the force sensor arrangement 300 is also placed in a tow coupling 65. The tow coupling 65 is substantially similar to the tow coupling 51 of Figures 1 and 2. The difference between the tow coupling 65 and tow coupling 51 of Figures 1 and 2 is that the tow coupling 65 is not axially bored. Another difference is that the tow coupling 65 further comprises a spacer foot 68. The tow coupling 65 is a tow ball.

[0113] In this implementation, the sensor arrangement comprises at least one screw 66 or at least one pin.

[0114] A sensor arrangement utilizing a screw 66 comprises threads 166, and an arrangement utilizing a pin comprises an adhesive or press-fit fixing at the threads 166. Besides that, the at least one screw 66 and the at least one pin are substantially similar. At least one screw 66 or pin may be inserted through at least one clearance hole in the neck of the tow coupling 65. In other words, the screw or pin is positioned in the neck of the tow coupling via a clearance hole. The screw or pin 66 is fixed only where it reaches the head of the tow ball 65. Beneficially, the movement or strain in screw or pin 66 is measured by at least one sensor 70. In the case that more than one screw or pin 66 is used, then the screws or pins should be distributed angularly around the vertical axis of the tow ball 65.

[0115] The at least one sensor 70 may be a magnetic sensor, which is substantially similar to the magnetic sensor 56 of Figures 1 . Also in this arrangement, beneficially, the sensor 70 which is a magnetic sensor senses the change in the location (i.e. movement) of the at least one screw 66 or pin.

[0116] In this arrangement, when the sensor 70 is a magnetic sensor, the force sensor arrangement 300 comprises a magnetic circuit. The magnetic circuit may incorporate a magnetostrictive material or an elastomer combined with a ferromagnetic material. The magnetostrictive material may be electroplated onto a first washer 71 or a second washer 72. The first washer 71 and / or the second washer 72 may be thermoplastic washers. The magnetostrictive material may be nickel.

[0117] In this arrangement, the force sensor arrangement 300 further comprises a permanent magnet 69 for generating a magnetic field.

[0118] In this arrangement, the strain in the screw 66 or pin may be used to modify the magnetic behaviour of the magnetic circuit. The magnetic field is generated by a permanent magnet 69. The strain in the screw 66 or pin is generated by the movement of the tow coupling 65. Consequently, the strain in the magnetostrictive material decreases the magnetic fielddifferentially between the at least one sensor 70 via the Villari effect as the tow coupling 65 bends. Therefore, forces acting on the tow coupling 65 may be measured.

[0119] Alternatively, the sensor 70 may be a precision inductive sensor. The sensor / s 70 may be embedded in the spacer foot 68. Beneficially, one or more sensors 70 sense the change in the location (i.e. movement) of the screw or pin 66.

[0120] In this arrangement, where the at least one sensor 70 is at least one precision inductive sensor, the first washer 71 may be made from a conductive material (such as copper or brass), stacked over an elastomeric washer 72, situated near the coil of an inductive sensor. The inductive sensor may be placed on a printed circuit board 67, whereby the movement of the at least one screw 66 and the consequent compression of the elastomer washer 72 is determined from the change in inductance of the coil of the inductive sensor on the circuit board 67. Therefore, forces acting on the tow coupling 65 may be measured. Beneficially, in this arrangement, a permanent magnet for generating magnetic field is not needed. Therefore, the system arrangement may be more compact.

[0121] The skilled person will appreciate that three screws 66 or pins are needed to separate the components of lateral, longitudinal and axial force from the tow coupling 65, but two screws 66 or pins are sufficient to measure lateral and longitudinal forces in the tow coupling 65. Accordingly, the sensor arrangement 300 comprises three screws or three pins. In another example, the sensor arrangement 300 comprises one or more screws 66 or one or more pins. The skilled person will also appreciate that the sensor arrangement 300 may comprise one or more sensors 70 for sensing the movement of one or more screws / pins. Generally speaking, one sensor is required to sense the movement of one screw / pin.

[0122] In each one of the examples in Figures 1 to 4 and 12 to 15, each sensor arrangement 100, 200, 300 may further comprise at least one inertial sensor. The function of the at least one inertial sensor is to measure the acceleration and angular velocity of the tow coupling. Therefore, beneficially, more precise data about the movement of the tow coupling may be obtained. The at least one inertial sensor may communicate using a communications interface shared with the magnetic or inductive or sigma-delta sensors. For example, they may share an I2C connection to an NFC communications bridge.

[0123] The at least one inertial sensor may be placed on or near the PCB in any one of the examples above. The skilled person will appreciate that the at least one inertial sensor may be placed in other places, further from the other components of the sensor arrangements. For instance the at least one inertial sensor may be placed in the tow connector and / or in the computing device 1004. Thus even though it is described that the inertial sensor is part of thesensor arrangement, the inertial sensor may be placed in other places than the other parts of the sensor arrangement. In other words, the at least one inertial sensor may be placed anywhere fixed relative to the vehicle body.

[0124] The skilled person will appreciate that other sensors may be used in the sensor arrangements to measure forces acting on the tow coupling such as optical position sensors based on laser speckle, Bragg fiber sensors, capacitive or piezoresistive sensors may be used to measure the bending forces on the towball.Communications modules and power delivery of the sensor arrangements

[0125] In each one of the examples of the sensor arrangements described herein, sensor data readings from the sensor arrangements 100, 200, 300 (and from the sensor arrangements shown in Figures 12 to 15) and from the at least one inertial sensor (if present) may be sent to an external computing device (e.g. the computing device 1004 shown in Figure 1 ) for further processing. Therefore, means for transmitting the sensor data and power supply is needed, and furthermore, that means of transmission will need to be suitable for use in a tow-hitch, where high impact forces, water splashes and vibration may be expected. The skilled person will appreciate that all of the examples of the sensor arrangements described herein may comprise the following transmitting means and power supply even if not shown in the figures.

[0126] In one example of the towball sensor arrangement, the sensor arrangements 100, 200, 300 may further comprise a connector for a cable to a brake controller or a communications module, with the connector protected by a projection of the steel shaft of the towball. The examples that comprise a hitch assembly may also have a cable exiting to a brake controller or communications module.

[0127] The sensor arrangements 100, 200, 300 may further comprise a near-fieldcommunication (NFC) energy harvesting device 53. The NFC harvesting device 53 may supply power to the sensor arrangements 100, 200, 300 and communicate data from the sensor arrangement 100 to another part of the system such as the computing device 1004.

[0128] The sensor arrangement 100, 200, 300 may further incorporate an NFC exciter to provide power and communications through the sealed interface cover. For example, the sensor arrangement 100, 200, 300 may comprise an NFC exciter 81 magnetically attached to the base of the shaft 153 of the tow coupling 51 as shown in more detail in Figures 10a, 10b and 10c. Accordingly, the NFC exciter 81 may serve as a connector for the sensor arrangement. The NFC exciter may also be coupled with an NFC energy harvesting device 53. The NFC exciter may comprise a communication module which communicates the sensor data readingsfrom the sensor arrangement 100 to the computing device (e.g. computing device 1004 as shown in Figure 1 ). The computing device may be, for instance, smartphone, a mobile phone, a tablet, a personal computer, or any other similar device. The computing device may be built into the towing vehicle (e.g. a module on the towed or towing vehicle or in the towing vehicle computer), or may be present in the towing vehicle (e.g. an app on a smartphone of the driver). The NFC exciter may also incorporate a communications method such as LIN, CAN or Bluetooth to further send the data to the external computing device.

[0129] The skilled person will appreciate that provision of power to the force sensor arrangements 100, 200, 300 and communication of data from the sensor arrangements 100, 200, 300 may be performed from the base of the shaft 153 of the tow coupling 51 . However, this location is exposed to impacts and weather and therefore a sealed interface with wireless power transfer is preferable. Therefore, the force sensor arrangement 100, 200, 300 may further comprise a sealed interface cover, which may be part of the positioning component 55. Beneficially, the sealed interface cover protects the interior of the sensor arrangement 100, 200 against the weather and wear and tear. Communication and power transfer through the sealed interface with wireless power transfer may be implemented by using an NFC exciter 81 magnetically attached to the base of the shaft of the tow coupling 51 and coupling the NFC exciter 81 with an NFC energy harvesting device 53.

[0130] The NFC excited 81 is shown in more detail in Figure 10a, 10b and 10c. The NFC exciter 81 may be powered from and / or communicate from vehicle wiring via a wiring loom 77. The NFC exciter 81 may attach to the base of shaft 153 of the tow coupling 51 via a magnet 74. Beneficially this will allow disconnection with a low risk of damage to either the tow coupling sensor arrangement or to the NFC exciter 81 . The NFC exciter 81 may be sealed against water and salt mist using an overmould 75 and / or cable grommet 76. The NFC exciter 81 comprises a PCB 80, the PCB comprising at least an antenna 79 and NFC reader device 78. The PCB 80 may further comprise the computation device 1004 (shown in Figure 1) and a CAN or LIN transceiver for communication with other systems.

[0131] Alternatively, the sensor arrangement 100, 200, 300 may be battery-powered, and directly transmit data from the sensor arrangement via a radio system such as Bluetooth. In this implementation, the NFC harvesting device 53 and the NFC exciter 81 are not present, and instead, the sensor arrangement 100, 200, 300 may comprise a battery for supplying power to the sensor arrangement 100, 200, 300 and an antenna for transmitting the sensed data from one or more sensors 57 to the external computing device. The battery and / or the antenna may be located in the same location as the NFC harvesting device and the NFC exciter. In this implementation, the sealed interface will be made suitable to allow radio communications. Theantenna may be used for two-way communication between the sensor arrangement and the external computing device (e.g. computing device 1004 of Figure 1 ).

[0132] In examples where the tow coupling is more protected (e.g. when installed in a raised hitch where it is protected from stones thrown up by wheels), a connector (e.g. similar to the one described in Figure 10) may be incorporated. The connector may be incorporated at locations (53), (64) or (73). In this configuration the tow coupling may be permanently wired to power and may directly connect to the computing device 1004 or the brake controller 1006 by a wired protocol such as CAN or LIN. Alternatively, it may receive power on the connector, but transmit wirelessly to the computing device 1004 or the brake controller 1006.

[0133] All of the examples of the sensor arrangements 100, 200, 300 of the present techniques may comprise a configuration memory. The memory may be a non-volatile memory. In all of the above-mentioned examples in Figures 1 to 3, a non-volatile memory may be required to compensate the output of the sensor circuits for nonlinearities and / or temperature offset. In addition, it may be necessary to store information about the orientation of the tow coupling installation in order to determine the lateral and longitudinal components of force. For certain applications, it may also be desirable to store length parameters of the trailer, or details of the towing ratings of the towing vehicle. The non-volatile memory may be flash memory within the processor component, an EEPROM located in the tow ball, or a file on an external system that is loaded and applied by that system using a communications interface (i.e the external computer). In other words, the configuration memory may be a part of each one of the sensor arrangements, or the configuration memory may be a part of the computing device 1004. Therefore, the sensor arrangement further comprises a configuration memory. Alternatively, the computing device 1000 comprises a configuration memory.

[0134] The skilled person will also appreciate that although not shown in the figures, all of the examples of the sensor arrangements may be embedded in a towbar or the trailer drawbar.Systems and methods for processing sensor data of the sensor arrangement

[0135] Figure 5 shows a diagram overview of methods for processing sensor data of the sensor arrangements and methods for improving trailer safety.

[0136] Figure 6 shows a flowchart of the method of the present techniques for processing sensor data of the sensor arrangement. The computing device 1004 is configured to perform any one of the steps of the method in Figure 6. The steps of the method in Figure 6 may be performed in any order, the steps may be combined together, and some steps may be omitted(e.g. if filtering is not required for a particular application, filtering does not have to be performed).

[0137] Beneficially, data obtained from the sensor arrangement may be processed for ease of further computations and a reduction in costs. The output of the method of processing sensor data of the sensor arrangement (shown in Figure 6) may be an input to the method 600 (shown in Figure 7).

[0138] The method for processing sensor data comprises step S500 of obtaining data from the at least one sensor of any one of the sensor arrangements described above. Therefore, the sensor arrangement is configured to measure forces acting on the tow coupling. The sensor arrangement is then configured to transmit the sensor data to the computing device 1004. Sensor data may be the sensed / measured forces acting on the tow coupling. The sensor data is obtained by the at least one sensor of the sensor arrangement and potentially by the at least one inertial sensor of the sensor arrangement. Sensor data may be obtained as raw values. This step is depicted as blocks (3) and (4) in Figure 5.

[0139] The method for processing sensor data obtained by the sensor arrangement may comprise S500 transforming the measurements of one or more sensors of the sensor arrangement into a vehicle coordinate system. In an instance that at least one optional inertial sensor is present in the force sensor arrangement, the method for processing sensor data obtained by the sensor arrangement may also comprise transforming the data obtained by the at least one inertial sensor (8) to the vehicle coordinate system.

[0140] The tow coupling may be installed in different orientations, and therefore both the sensor data from the at least one sensor and the data from the optional one or more inertial sensors (8) may be transformed into the vehicle coordinate system before use. This is beneficial for obtaining more precise readings from one or more sensors of the sensor arrangement. This may be done by enforcing installation in a particular orientation (e.g. by placing flats 155 on the sides of the tow ball base for guidance); and / or by having the installer configure the non-volatile storage of the at least one sensor and / or the inertial sensor; and / or by automatic detection of orientation (see e.g. REDARC patent PCT / AU2021 / 050942). This process is done by a matrix multiplication to unmix (7) the forces. After this step, separate inertial sensor values are obtained that may include, acceleration, a = (aiong, aiat) and the yaw rateused in further processing in blocks (22), (23) and (24).

[0141] The unmixing (7) matrix may comprise a product of two matrices Q and B, where Q is the rotation matrix determined using techniques such as REDARC patentPCT / AU2021 / 050942, and B is a calibration matrix for sensor output as a function of force at the trailer hitch, determined at manufacturing time.

[0142] Alternatively, the calibration matrix B may be combined with the linearisation step (5), and both steps replaced with at least one polynomial fit of the sensor readings and their products of at least the first order. The polynomial may be determined for at least one measurement axis during manufacturing and stored in a non-volatile memory. The output of the at least one polynomial may then be multiplied by the rotation matrix Q to complete the unmixing step (7). Since some sensor embodiments have more sensor outputs than desired measurement axes, the coefficients of the polynomial may be best produced using a regularising algorithm such as least absolute shrinkage and selection operator (LASSO), Tikhonov or elastic net regularisation rather than least squares to prevent over-fitting.

[0143] To reduce manufacturing test time, regularisation may be done on a sample at a product or batch level on a larger set of test forces, followed by ordinary least squares on a smaller subset per unit. Le. in the case that two axes each are used from two magnetic sensors, the set of sensor readings and first order products is a vector of length 15 X =many Of which will be approximately linearly dependent, leading to instability of the least squares algorithm, and the need for measurements at more than 10 combinations of force F = [Fx, Fy] (note that the force values should be approximately uniformly distributed over the range of forces expected from a trailer in operation). Regularisation may be applied to a set of 20 X at different values of F. The non-zero entries in the fit vector ^regularisedwil1identify the elements of X that should be fitted in bulk production, and therefore the number of force inputs to be tested.

[0144] It might be also possible to determine which elements of X are significant for estimation of force using finite element analysis for the strain gauge construction methods. However, multiphysics analysis would be required for the magnetic methods.

[0145] The installation in a particular orientation may introduce additional strains on some parts of the tow coupling. Therefore, after the installation, the measured force should be recorded in the configuration memory, and the strain due to installation should be subtracted from the measured strain during subsequent operations. The configuration memory may be a part of the computing device and / or the sensor arrangement.

[0146] In some examples, the installation or operation process may also include the loading of the hitch or tailgate with a known mass to calibrate the change in vehicle pitch withmass. This can then be used to estimate tow ball weight from pitch changes using the inertial sensor.After this, estimates of forces in the tow coupling are as follows:• F = {Fiong’ Fiat) (see blocks 10, 1 1 , 25 in Figure 5) the vector of brake forces in the horizontal plane• F axial the axial hitch force

[0147] The method for processing sensor data obtained by the sensor arrangement may further comprise correcting the obtained sensor data S502. The step of sensor data correction may comprise correcting the obtained raw value readings by temperature compensation and / or linearisation. The method for processing sensor data comprises a step of obtaining data from the at least one sensor of any one of the sensor arrangements described above.

[0148] The data readings from one or more sensors of the sensor arrangement may be read as raw value measurements (4), such as bridge voltage for a strain sensor, magnetic flux density for a magnetic sensor or Villari effect sensor, or inductance for an inductive position / Villari effect sensors (using saturation effects). These measurements (i.e. raw values) may be nonlinear in the tow coupling force. Moreover, these measurements (i.e. raw values) may have temperature variations and redundant values for any given measurement. Beneficially, the method and the system of the present techniques correct at least the above- mentioned problems by temperature compensation and / or linearization.

[0149] Temperature compensation is performed using known physical parameters of the materials and sensors involved. For instance, the temperature compensation may comprise polynomial temperature compensation of strain gauges.

[0150] Linearisation (5) of the raw values may also be performed. Linearisation, where sensor readings are converted to force estimates using a matrix inverse or pseudo-inverse, and offsets are interpolated from tables measured at the design or production of the sensor.

[0151] The method for processing sensor data obtained by the sensor arrangement may further comprise S504 filtering the corrected sensor data and / or the obtained raw sensor data.

[0152] Data from the sensor arrangement may most likely contain high-frequency components from the vibration of the towing vehicle and trailer. This data is undesirable. For instance, the data useful for braking control is largely within the range 0-10Hz, possibly extending to 50Hz for some brake actuators. Therefore, advantageously, the sensor data isfiltered (6) with a suitable filter. The suitable filter may be for instance a FIR, HR or CIC filter, depending on the bandwidth of interest.

[0153] The method for processing sensor data obtained by the sensor arrangement may further comprise determining trailer brake force S506. In other words, the computing device 1004 is configured to determine brake force.

[0154] The skilled person will understand that for approximately linear sensor such as the strain gauge, Villari and magnetic sensors, some of the processing steps above may be reordered and / or combined without loss of accuracy. For a less linear sensors it may be required that the linearisation (5) be done before any other steps.

[0155] Beneficially, the computing device may separate out force due to different brakes of the trailer without requiring individual torque sensors at each wheel. If the trailer has common brake wiring for all brakes, then the difference in braking force between the two sides may be estimated by calculating the contribution to lateral force on the tow coupling from the following equations: long ~ Floft T Ffight + sgrri otWhere:• Fiong, Fiat> Fieff Fri ht (25, 15) are the longitudinal and lateral forces on the tow coupling and the left and right brake forces respectively• s and scr0SSare the forward and cross slopes respectively. These values may be estimated using a Kalman filter as described in REDARC patent PCT / AU2021 / 050942. The skilled person will appreciate that these values can be also obtained, for example, by averaging a measurement of gravity using an accelerometer (an inertial sensor) if the vehicle moves on a straight road. Alternatively, on most roads, the cross slope may be assumed as a nominal value, and the forward slope can be obtained from a map system and a GPS reading.• g is the acceleration due to gravity,• mtot, mbau are the trailer and ball masses respectively• d) is the yaw acceleration of the trailerIzzis the yaw moment of the trailerlaxie, Idraw are the axle length and length from axle to coupling

[0156] These equations may either be solved directly using available estimates of the parameters or using correlation with the braking control signal may be solved for the differential force with respect to the braking output. The intermediate calculated values(27) are also of use in trailer brake condition monitoring, where a is the brake control signal.

[0157] Alternatively, if the trailer has individual brake wiring for each wheel (or each side), then the differential force per wheel (or per side) with respect to the control input at(denoted may be determined more accurately. This may be determined by driving each wheel (or each side) with a different pattern of braking and using a system identification method such as N4SID, MOESP or canonical variates analysis to determine the force produced by each wheel. To facilitate the use of cross-correlation, the pattern of braking may be a small perturbation such as a Walsh code added to the normal braking signal. Walsh code is a set of mathematical functions used in digital signal processing and communication systems. Walsh code / s enable the transmission and reception of multiple signals simultaneously without interference.Systems and Methods for increasing towing safety

[0158] Beneficially, there are many potential usages of trailer force measurements obtained from the sensor arrangements of the present techniques, all of which increase towing safety. This is especially true when these measurements are combined with the control of trailer braking and / or with inertial measurements and / or with vehicle speed measurements. Some exemplary, non-limiting, applications are described below in the method for increasing towing safety in Figure 5 and Figure 7.

[0159] Figure 7 shows a method for increasing towing safety 600. This method is performed by the system depicted in Figure 1 . Therefore, the system of Figure 1 is configured to perform the method 600.

[0160] The method for increasing towing safety 600 comprises using the processed sensor data S602. In other words, the computing device 1004 is configured to use the processed sensor data.

[0161] The processed sensor data are the output of the method described in Figure 6. The computing device may also use raw data from the sensor arrangement.

[0162] Based on the processed and / or raw sensor data from the sensor arrangement, the computing device is configured to determine at least one property of the tow vehicle-trailercombination. A property of the tow vehicle-trailer combination may be defined as any information about the trailer and / or the tow vehicle obtained in any one of the steps of the method 600 shown in Figure 7. Based on the determined at least one property of the tow vehicle-trailer combination, the computing device is configured to transmit a control signal to a trailer brake controller to control brakes of the trailer and / or to transmit a message to a driver of the tow vehicle.

[0163] The computing device may receive speed measurements (13) from at least one sensor on the vehicle. These speed measurements may be received directly from at least one speed sensor on the vehicle or from an application (e.g. smartphone application) which has received the speed readings from at least one sensor on the vehicle. Therefore, the computing device may be configured to be in a communication with at least one speed sensor on the vehicle and to receive readings from the at least one speed sensor on the vehicle. In other words, the computing device may be configured to receive information about the velocity of the tow vehicle from an external source. However, if ldraw(length from axle to coupling ) is available in the calibration and configuration (1 ) (which may be available, for instance, in the configuration memory of the computing device), then the vehicle speed may be determined using a Kalman filter with updated inputs from the forward acceleration alongand correction inputs from the velocity estimatorsi gwhe e is the pitch rate or (whenaccelerating) where 9 is the hitch angle calculated as 9 = tan-1).\FlongJ

[0164] The method 600 may comprise determining braking level of the trailer brakes S608. In other words, the computing device is configured to transmit a control signal to the trailer brake controller to control the brakes of the trailer based on the control signal. An exemplary direct brake control block diagram 19 is shown in Figure 8. The determined braking level of the trailer brakes may be termed as trailer braking level property. Generally speaking the trailer breaking level property is the adjustment of forces acting on the tow coupling to a target value. In other words, trailer braking level property is an adjustment of a parameter of a trailer brake controller that changes the amount of force acting on the tow coupling to a target value.

[0165] In one example, as shown in Figure 8, the processed sensor data may be used in a control loop 30 by the computing device to generate a control signal for the control of trailer brakes. In this example, the brakes would be directly controlled using, for example, by a PID controller 31 with the aim of reducing Fiongto ON. In other words, the control signal transmitted from the computing device to the brake controller comprises instructions to change the amount of longitudinal forces acting on the tow coupling to ON.

[0166] Alternatively, the PID controller would target a specified value of Flongto allow a towing vehicle with regenerative braking to recover more energy from the trailer during braking. In other words, the control signal transmitted from the computing device to the brake controller comprises instructions to change longitudinal forces acting on the tow coupling to a target value. For instance, the target value of Ftongmay be mnomatong, where mnomis the rated unbraked trailer capacity of the towing vehicle, configured by the installer (e.g. by entering the VIN), or it may be mnomanomwhere anom« 0.4g is a conservative safe rate of braking with an unbraked trailer. Beneficially, the towing vehicle may recover kinetic or potential energy from the trailer: Erecovered= Fiong■ d over a braking distance d. Beneficially also, the additional force on the vehicle Flongis less than or equal to the force that a towing vehicle is rated to accept when braking with a light unbraked trailer, meaning that the vehicle does not require modification to accept the additional energy.

[0167] In examples with direct brake control, the computing device may send braking control data to an external power electronic module 32 to generate the high-power signals 33 for the brake actuators in the trailer.

[0168] In a case where individual wiring is provided to each trailer brake, braking may be controlled between the sides of the trailer to reduce Flatto ON, thereby allowing an improvement in direction control when braking, and ensuring that the trailer follows the same path as the vehicle.

[0169] The method 600 may comprise configuring automatic gain S610. In other words, the computing device is configured to configure automatic gain of the trailer brake controller. An exemplary block diagram for controlling gain is shown in Figure 9. The configured automatic gain of the trailer brake controller may be termed as trailer gain property. Advantageously, by automatic configuration of gain, the need for a hand controller of the trailer brakes may be eliminated.

[0170] In an example, the computing device may configure a trailer brake controller 41. As shown in an exemplary example in Figure 11 , brake controllers typically have an output wherein the measured deceleration (the x-axis of curves 701 through 706), is multiplied by a gain and has an offset 710 added, to produce an output braking level (the y-axis of curves 701 through 706). A default value of this gain may be configured by the computing device 1004 to start with no braking at 0 deceleration, and reach full braking at 1 gravity of deceleration (curve701 ). However, the actual curve is expected to be different to this, and may be nonlinear (curve702), and the computing device may adjust the gain (slope) and boost (offset) to match the actual curve 702 more closely. To perform this, the computing device 1004 is informed whenthe trailer brakes are applied (e.g. when the brake lamps are on), and will then monitor the force applied on the vehicle by the trailer. A residual longitudinal force at high deceleration will lead to an adjustment in slope, and a residual force at a low deceleration may lead to an adjustment in boost (offset). This will result in a gradual approach to the conservative brake control curve 706, where the trailer force exceeds the optimal nonlinear curve 702. Beneficially, this means that the trailer will not push the vehicle during braking, and this will be achieved without requiring the driver to configure the controller manually. Alternatively, the computing device 1004 may instead target a force value of Fiong, such as those given above to produce a brake control curve 705 suitable for vehicle energy recovery, wherein the brake controller is configured to allow the trailer to apply a configured level of force on the towing vehicle with the same benefits described above. In a preferred embodiment, Flong= Munratedg where Munratedis the unbraked tow rating of the towing vehicle and g is acceleration due to gravity. In another alternative, the computing device 1004 may target a force value of Flong= MunratedAlongwhere is the current deceleration of the vehicle.

[0171] The skilled person will appreciate that the technique of described in relation to Figure 1 1 may furthermore be performed differently in different speed ranges, as trailer brake characteristics 702 are known to differ with speed. This will improve both energy recovery and comfort, but will require the computing device 1004 to maintain different values of the gain and boost for different speed ranges.

[0172] The method 600 may comprise determining trailer ABS property. Thus, the method comprises preventing or reversing wheel stalls S612. In other words, the computing device is configured to prevent or reverse wheel stalls. This step is shown as block (20) ABS in Figure 5.

[0173] Preventing or reversing wheel stalls can be implemented if brakes are separately connected to the brake control power electronics (i.e. trailer brake controller which controls brake control electronics). In this case, the computing device may continuously calculate the dF- loop gain from whereby it can decrease braking output if the rate of force with respect tothat brake output becomes negative or close to zero. This calculation may be termed as the ABS property. Beneficially, this would prevent or reverse wheel stalls. In other words, the trailer ABS property is a decrease in braking of at least one trailer brake if a rate of force with respect to the at least one brake output becomes negative or close to zero.

[0174] The method 600 may further comprise detecting and correcting trailer sway S616. In other words, the computing device is configured to detect and correct trailer sway. Detecting and correcting trailer sway may be termed as trailer sway property.

[0175] In one example of sway detection, the computing device may estimate trailer kinetic energy as I Fiataiatdtdt, and apply sway control if the kinetic energy reaches athreshold. In another example, the computing device may estimate the power transfer from the trailer to the towing vehicle as Flatalatdtdt and place a threshold on this to detect sway.Note that in these estimators, leaky integrations are performed to estimate lateral velocity. These leaky integrations may be replaced with bandpass filters, high-pass filters or Kalman filters. In another example, the computing device may solve the differential equations of trailer motion to determine the yaw rate of the trailer and apply sway control if the trailer yaw rate exceeds the tow vehicle yaw rate. Therefore, beneficially, the determination of the yaw moment and sway is achieved independent of tow vehicle characteristics. In other words, the trailer sway (which may be termed trailer sway property) is determined on an estimation of any of trailer lateral acceleration, trailer kinetic energy or trailer yaw rate.

[0176] If velocity measurements (28) are available, the computing device may not perform sway control when travelling under 50km / h.

[0177] Beneficially, the computing device may generate a control signal, and transmit that control signal to the trailer brakes controller that applies brakes autonomously on the trailer when trailer sway is detected and thus perform the sway control.

[0178] The method 600 may comprise monitoring trailer brake condition S614. In other words, the computing device is configured to monitor trailer brake condition. The trailer brake condition property is a performance measure of at least one trailer brake actuator. Monitoring trailer brakes conditions yields a status of the trailer brake conditions (i.e. brake condition property).

[0179] The computing device may monitor trailer brake conditions. Consequently, the computing device may output a status of the trailer brake conditions (i.e. trailer brake condition property). Then, the computing device may report brake condition faults in any of the following trailer brake conditions. d F-• Differs significantly between wheels (e.g. by more than 200N) (i.e. one or more brakes are unbalanced)* ^da ~ls hi9herthanathreshold of 200N (i.e. the trailer is unbalanced side to side in its braking)dFg°^9< 100 / V or < 100 / V anywhere in the range 0.1 < a < 0.8 (i.e. one or morebrakes are badly adjusted or worn.

[0180] In other words, the computing device is configured to monitor the conditions of the brakes on the trailer and report the result of the monitoring to the driver of the vehicle. The skilled person will appreciate that the above-mentioned examples are merely exemplary and other brake conditions may be monitored.

[0181] In an instance that a brake condition fault is detected, the computing device may output a warning about unacceptable brake conditions to the driver of the vehicle. The braking fault is any of imbalanced braking between brake actuators, brakes not engaging at high control levels, or brake force saturating at low control levels. Therefore, method 600 may further comprise outputting a warning to the driver of the vehicle if a brake condition fault of the trailer is detected. In other words, the computing device may be configured to output a warning to the driver of the vehicle if a brake condition fault of the trailer occurs. The warning may be displayed on a graphical user interface. The graphical user interface may be displayed, for instance, on a vehicle dashboard and / or a smartphone application.

[0182] Beneficially, the computing device is configured to adjust individual brake actuators for maximum braking force. This is based on the measurement of the differential braking force due to a low-level braking signal superimposed on the brake signals to each wheel (by for instance using a Walsh code). This braking force is then fitted with curves as describes in S610 applied for each wheel. The brake controller may then use this curve to determine an output level that provides an equal force on each wheel. The same principle may be applied if the wiring to each side of the trailer is separate, allowing the brake controller to balance the force from the wheel groups on either side of the trailer.

[0183] The skilled person will appreciate that the braking force per wheel can be used for condition monitoring, and may generate early warnings for brake maintenance.

[0184] The method 600 may further comprise determining trailer mass distribution S618. In other words, the computing device may determine trailer mass distribution. The determined trailer mass distribution may be termed as trailer mass distribution property. The trailer mass distribution property is a distribution of trailer mass. In other words, trailer mass distribution property includes at least one of trailer total mass, trailer yaw moment of inertia or trailer ball weight.

[0185] In one example, to determine the mass distribution of the trailer, the computing device may estimate key trailer motion parameters (yn.baU, mtot, Izz) from the equations ofmotion noted above, together with the integration of the following equations of motion for^trailer -d atow vehicle ~ ~^vtow vehicle

[0186] If velocity of the tow vehicle vtow vetlicleis available from the computing device or other module or any other velocity sensor, then the estimate of the key trailer motion parameters may be more accurate.

[0187] In another embodiment,trailermay be measured using a sensor on the trailer, and for the case of a sensor incorporated in the coupling body of the trailer, Mtow veflLcLemay be measured using a sensor on the towing vehicle. For example, a sensor included with the power electronics that generate braking signals. Therefore, the computing device may be configured to receive a signal from one or more additional sensors.

[0188] The computing device may post a warning 21 if any of these exceed preprogramed parameters stored in the memory such as the vehicle or trailer tow ball mass ratings, the vehicle tow rating, or the trailer axle rating. The sensor arrangement may post a warning 21 via an external connection. A warning may also be posted if the critical speed of the trailer is calculated to be too low based on analysis of the Routh-Hurwitz stability criteria of the equations of motion under conservative assumptions (or data in calibration and configuration 1 ) for axle cornering stiffness. Therefore, the method S600 may further comprise informing the driver of the vehicle of a potential hazard. In other words, the computing device is configured to: based on the determined at least one property of the trailer, transmit a warning message to a driver of a tow vehicle.

[0189] The trailer mass distribution property may also be used for billing of trailer usage or trailer contents.

[0190] As an alternative example of warning about an unstable trailer, instead of making conservative assumptions on cornering stiffness, the trailer / veh icle dynamics may be measured from a and F, and a subspace system identification performed with at least 5 degrees offreedom. In this case, the eigenvalues of the state equation may be used to determine the stability and margin of the system. Thus, potential trailer instability may be based on statespace eigenvalues of at least one trailer hitch measurement. The state space eigenvalues are determined using a subspace parameter estimation method. Therefore, beneficially, the stability of the trailer may be determined, and a warning to the driver of the vehicle may be transmitted if an instability is found.

[0191] In this step, if trailer brake condition property and / or trailer mass distribution property are outside a safe threshold, the computing device may generate a warning message which is transmitted to a driver of a vehicle. This may be done by sending the message from the computing device to another computing device (e.g. a smartphone or a vehicle dashboard computer). Alternatively, the computing device may comprise a user interface which conducts the message to the driver of the vehicle. The message may be, for instance, in form of text and / or sound.

[0192] The method 600 further comprises based on the determined at least one property of the tow vehicle -trailer combination, transmitting a control signal to the trailer brake controller to control the brakes of the trailer S620. In other words, the computing device is configured to: based on the determined at least one property of tow vehicle -trailer combination, transmit a control signal to the trailer brake controller to control the brakes of the trailer. Thus, computing device may be configured to feedback the brakes directly.

[0193] The at least one property which may be used to generate a control signal for the trailer brake controller is any one of the properties generated in, S608, S610, S612 and S616. In other words, the at least one property that may be used to generate a control signal for the trailer brake controller is any one of: trailer braking level property, trailer gain property, trailer ABS property and trailer sway property. The skilled person will also appreciate that it is possible to generate a control signal for the trailer brake controller based on the trailer brake condition property and / or trailer mass distribution property (e.g. emergency stop).

[0194] The method 600 further comprises based on the determined at least one property of the tow vehicle- trailer combination, transmitting a message to a driver of a tow vehicle 620. In other words, the computing device is configured to: based on the determined at least one property of the tow vehicle-trailer trailer combination, transmit a message to a driver of a tow vehicle.

[0195] The at least one property which may be used for transmitting a warning message to a driver of a tow vehicle is at least any one of the properties generated in S614 and S618. In other words, the at least one property that may be used to transmitting a warning message toa driver of a tow vehicle is any one of: the trailer brake property and / or trailer mass distribution property. However, the skilled person will appreciate that the system may be configured to transmit the message to the driver of the vehicle even based on at least one of: trailer braking level property, trailer gain property, trailer ABS property and trailer sway property (e.g. emergency sway warning to the driver).

[0196] In other words, the computing device is configured to, based on the determined at least one property of the tow vehicle- trailer combination, transmit control signal to a trailer brake controller to control brakes of the trailer and / or transmit a message to a driver of a tow vehicle. The at least one property for both transmitting control signal to a trailer brake controller to control brakes of the trailer and transmitting a warning message to a driver of a tow vehicle may be any one of: trailer braking level property, trailer gain property, trailer ABS property, trailer sway property, trailer brake condition property, trailer mass distribution property.

[0197] The skilled person will appreciate that all of the above-mentioned steps of the method 600 may be combined together, unless stated otherwise. The method 600 illustrates the capabilities of the present system, therefore, the skilled person will also appreciate that not all of the steps of the method 600 must be performed. The user can choose the desired capability (i.e. method step) to be performed by the method 600 based on the desired function. Alternatively, the system may automatically choose the desired capability (i.e. method step) to be performed by the system. The user / system can also choose to perform all of the steps of the method 600.Interpretation

[0198] Unless specifically stated otherwise, as apparent from the following discussions, it is appreciated that throughout the specification discussions utilizing terms such as "processing," "computing," "calculating," “determining”, analyzing” or the like, refer to the action and / or processes of a computer or computing system, or similar electronic computing device, that manipulate and / or transform data represented as physical, such as electronic, quantities into other data similarly represented as physical quantities.

[0199] In a similar manner, the term “controller” or "processor" may refer to any device or portion of a device that processes electronic data, e.g., from registers and / or memory to transform that electronic data into other electronic data that, e.g., may be stored in registers and / or memory. A “computer” or a “computing device” or a "computing platform" may include one or more processors.

[0200] Reference throughout this specification to “one embodiment”, “some embodiments” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, appearances of the phrases “in one embodiment”, “in some embodiments” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

[0201] As used herein, unless otherwise specified the use of the ordinal adjectives "first", "second", "third", etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner.

[0202] In the claims below and the description herein, any one of the terms comprising, comprised of or which comprises is an open term that means including at least the elements / features that follow, but not excluding others. Thus, the term comprising, when used in the claims, should not be interpreted as being limitative to the means or elements or steps listed thereafter. For example, the scope of the expression a device comprising A and B should not be limited to devices consisting only of elements A and B. Any one of the terms including or which includes or that includes as used herein is also an open term that also means including at least the elements / features that follow the term, but not excluding others. Thus, including is synonymous with and means comprising.

[0203] It should be appreciated that in the above description of exemplary embodiments of the disclosure, various features of the disclosure are sometimes grouped together in a single embodiment, Fig., or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claims require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this disclosure.

[0204] Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the disclosure, and form differentembodiments, as would be understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0205] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the disclosure may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0206] Embodiments described herein are intended to cover any adaptations or variations of the present invention. Although the present invention has been described and explained in terms of particular exemplary embodiments, one skilled in the art will realize that additional embodiments can be readily envisioned that are within the scope of the present invention.

[0207] Where any or all of the terms "comprise", "comprises", "comprised" or "comprising" are used in this specification (including the claims) they are to be interpreted as specifying the presence of the stated features, integers, steps or components, but not precluding the presence of one or more other features, integers, steps or components.

Claims

The claims defining the invention are as follows:1 . A system for a tow vehicle-trailer combination, the system comprising: a sensor arrangement for measuring forces acting on a tow coupling; wherein the sensor arrangement is placed in the tow coupling; a computing device for processing data received from the sensor arrangement; wherein the computing device is configured to: receive data from the sensor arrangement; determine at least one property of the tow vehicle-trailer combination based on the received data from the sensor arrangement; and based on the determined at least one property of the tow vehicle-trailer combination, transmit at least one control signal to a trailer brake controller to control brakes of the trailer and / or transmit a message to a driver of a tow vehicle.

2. The system of claim 1 , wherein the at least one property of the tow vehicle-trailer combination is any one of: trailer braking level property, trailer brake gain property, trailer ABS property, trailer sway property, trailer brake condition property, trailer mass distribution property.

3. The system of any one of the preceding claims, wherein the computing device is configured to receive information about a velocity of the tow vehicle from an external source4. The system of any one of the preceding claims, wherein the trailer braking level property is an adjustment of a parameter of a trailer brake controller that changes the amount of force acting on the tow coupling to a target value.

5. The system of claim 4, wherein the target value is a value which allows the tow vehicle with regenerative braking to recover energy from the trailer during braking.

6. The system of any one of the preceding claims, wherein the trailer gain property is the gain of the trailer brake controller.

7. The system of claim 6, wherein the trailer gain property is used to apply an offset to braking of the trailer brakes to allow energy recovery by the tow vehicle.

8. The system of any one of the preceding claims, wherein the trailer ABS property is a decrease in braking of at least one trailer brake if a rate of force with respect to the at least one brake output becomes negative or close to zero.

9. The system of any one of the preceding claims, wherein the trailer sway property is sway of the trailer.

10. The system of claim 9, wherein the computing device is configured to solve differential equations of trailer motion to determine the yaw rate of the trailer and apply sway control if the trailer yaw rate exceeds the tow vehicle yaw rate, independently of tow vehicle characteristics.11 . The system of any one of the preceding claims, wherein the trailer brake condition property is a performance measure of at least one trailer brake actuator.

12. The system of any one of the preceding claims, wherein the trailer mass distribution property includes at least one of trailer total mass, trailer yaw moment of inertia or trailer ball weight.

13. The system of any one of the preceding claims, wherein the system applies an offset to braking of the trailer brakes to allow energy recovery by the tow vehicle while remaining within a limit.

14. The system of claim 13, wherein the limit is a force limit.

15. The system of claim 13, wherein the limit modifies the braking of the trailer to emulate the force applied by an unbraked trailer of a specified weight.

16. The system of any one of the preceding claims, wherein the computing device is configured to determine separate forces acting on the tow coupling.

17. The system of any one of the preceding claims, wherein the computing device is configured to correct data received from the sensor arrangement by temperature compensation and / or linearization.

18. The system of any one of the preceding claims, wherein the sensor arrangement is configured to measure forces acting on the tow coupling along X, Y, and Z axes.

19. The system of any one of the preceding claims, wherein the sensor arrangement further comprises at least one inertial sensor.

20. The system of any one of the preceding claims, wherein the sensor arrangement further comprises a near-field-communication, NFC, energy harvesting device and NFC exciter.21 . The system of any one of the preceding claims, wherein the sensor arrangement further comprises a magnetic field sensor, a magnetized pin and magnetic concentrator.

22. The system of any one of the preceding claims, wherein the sensor arrangement further comprises one or more strain gauges contained within the coupling assembly.

23. The system of any one of the preceding claims, wherein the tow coupling is a tow ball.

24. The system of claim 23, wherein the sensor arrangement is placed coaxially in a bore of the tow ball.

25. The system of any one of claims 1 to 20, wherein the sensor arrangement comprises: at least one pin, wherein each one of the at least one pin is fixed to one portion of the tow coupling and passing through a neck of the tow coupling via a clearance hole; and at least one sensor embedded in a spacer foot of the tow coupling.

26. The system of any one of claims 1 to 22 and 28, wherein the tow coupling comprises: a trailer coupling body to be installed on a trailer drawbar; a spacer attaching to the trailer drawbar; and the sensor arrangement is attached to the coupling body or the spacer.

27. The system of any one of the preceding claims, wherein the tow coupling is on the vehicle or the trailer.

28. The system of any one of the preceding claims, further comprising the trailer brake controller.

29. The system of claim 28, wherein the brake controller is operable without a hand control.

30. A tow ball comprising: the system of any one of claims 1 to 25.

31. A tow ball comprising: a sensor arrangement which is configured to measure forces acting on the tow ball in at least one and up to three dimensions along X, Y and Z axis of the tow ball; wherein the sensor arrangement is configured to transmit the measured forces to a computing device; wherein the sensor arrangement is placed in the tow ball.

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