Trailer yaw rate estimator

Abstract

The present disclosure discloses a trailer yaw rate estimator (100). The trailer (10) and a truck (20) form a vehicle combination equipped with one or more sensors (15, 25) for providing sensor data (115, 125) characterizing the yaw rate (50) of the trailer (10). The estimator (100) includes a data processing unit configured to estimate a yaw rate (50) of the trailer (10) based on the provided sensor data (115, 125). The sensor data (115, 125) includes at least one of a wheel speed value of one or more wheels of the trailer (10), a steering angle (70) of the truck (20), a steering angle of the trailer (10), an articulation angle (60) between the trailer (10) and the truck (20), a yaw rate of the truck (20), and a vehicle speed value of the truck (20).

Description

TECHNICAL FIELD

[0001] The present invention relates to a trailer yaw rate estimator, in particular to a trailer yaw rate estimation method based on trailer wheel speed values. BACKGROUND

[0002] While trucks are usually equipped with a yaw rate sensor, conventional trailers are rarely installed with such a sensor. However, trailer yaw rate is one of the important state variables for estimating the current and future driving state of a trailer or vehicle combination. The trailer yaw rate value can be combined with the yaw rate of the truck (tractor) towing the trailer, so as to reliably assess the vehicle state and predict unstable driving conditions of the entire vehicle combination.

[0003] In addition, even if the tractor does not use the trailer yaw rate (for example, for future state estimation), the trailer yaw rate is usually an input parameter required by environmental sensors. Such environmental sensors are not only installed on trucks, but also on trailers. For example, the environmental sensors on the truck can take the signal of the yaw rate sensor as an input parameter to determine the driving direction of the trailer. Such environmental (perception) sensors installed on the trailer also need to take the trailer yaw rate as an input parameter.

[0004] For example, as a typical representative of environmental sensors, a radar sensor can be installed on the trailer. The radar sensor needs to take the yaw rate of the trailer itself as an input parameter to correctly interpret the driving scene. Based on the obtained yaw rate and other optional input parameters, the exemplary radar sensor can distinguish whether the detected object is a stationary object or a moving object. For example, when the trailer is turning (the yaw rate is not zero), trees and other objects may appear to be stationary, even if the trailer itself is turning. If the exemplary radar sensor can obtain the yaw rate data, such a scene can be correctly interpreted. This principle also applies to cameras and other environmental sensors. Since conventional trailers cannot provide such information by themselves, they have to rely on the yaw rate value provided by the truck. However, the value provided by the truck may not be accurate enough, or even missing. In either case, an estimator that can independently estimate the yaw rate of the trailer itself is needed, so as to not rely on the yaw rate data obtained from the truck. SUMMARY

[0005] The estimator of claim 1 or the method of claim 9 can at least overcome some of the above-mentioned problems. The dependent claims refer to further preferred embodiments of the subject matter of the independent claims.

[0006] The present disclosure relates to a trailer yaw rate estimator, wherein a trailer and a truck form a vehicle combination, said vehicle combination being equipped with one or more sensors for providing sensor data characterizing a yaw rate of the trailer. The yaw rate estimator comprises a data processing unit configured to be able to estimate the yaw rate of the trailer based on the provided sensor data. The sensor data comprises at least one of: - a rotational speed value of one or more wheels of the trailer; - a steering angle of the truck; - a steering angle of the trailer; - an articulation angle between the trailer and the truck; - a yaw rate of the truck; - a vehicle speed value of the truck.

[0007] The steering angle of the trailer refers to the steering angle of a trailer with a steering axle or bogie (e.g. a trailer with steering controlled by a towbar). The rotational speed value of the wheel can be taken from a wheel on a non-steering axle or non-bogie axle and can be measured on both sides of the same axle.

[0008] Optionally, the data processing unit is further configured to additionally refer to at least one of the following parameters when estimating the yaw rate: - a parameter characterizing a wheelbase of the trailer; - a parameter characterizing a track of the trailer; - a parameter characterizing a wheelbase of the truck; - a parameter characterizing a track of the truck; - a parameter defining a position of a coupling between the trailer and the truck (e.g. a kingpin reference or a distance between the kingpin and at least one axle).

[0009] The at least one of the above parameters can be a geometric parameter defining a geometry of the trailer and / or the truck. In the present disclosure, the term "characterizing" is used to indicate a functional correspondence. For example, data characterizing a yaw rate refers to all data that has an influence on the yaw rate, i.e. a change in such data leads to a change in the yaw rate. The parameter characterizing a wheelbase can be a specific value of the wheelbase or any other value from which the wheelbase can be derived. These parameters can be stored in the estimator or can be retrieved from other components of the trailer or truck, e.g. a memory or an electronic control unit (ECU).

[0010] The one or more sensors can comprise a plurality of trailer sensors mounted on the trailer. In this case, optionally, the data processing unit is configured to estimate the yaw rate based on trailer sensor data provided by the plurality of sensors mounted on the trailer only. The trailer sensor data comprises at least one of: - rotational speed values of two trailer wheels installed on opposite sides of the same trailer axle, e.g. a non-steered axle; - the articulation angle between the trailer and the truck in combination with a wheel rotational speed value of one of the trailer wheels.

[0011] The one or more sensors can comprise a plurality of truck sensors installed on the truck. In this case, optionally, the data processing unit is configured to estimate the yaw rate based on truck sensor data provided by the plurality of truck sensors installed on the truck only. The truck sensor data comprises at least one of: - a wheel rotational speed value of at least one wheel of the truck in combination with the truck steering angle; - a wheel rotational speed value of at least one wheel of the truck in combination with the articulation angle between the trailer and the truck; - a yaw rate value of the truck; - a longitudinal speed of the truck in combination with the truck steering angle and / or the articulation angle.

[0012] The one or more sensors can comprise at least one truck sensor installed on the truck and at least one trailer sensor installed on the trailer. In this case, optionally, the data processing unit is configured to estimate the yaw rate based on a combination of truck sensor data provided by the at least one truck sensor and trailer sensor data provided by the at least one trailer sensor. The combination of sensor data comprises at least one of: - the truck steering angle and a wheel rotational speed value of one of the trailer wheels; - a plurality of wheel rotational speed values of at least one truck wheel and at least one trailer wheel.

[0013] A further embodiment relates to a trailer with trailer sensors. Optionally, the trailer is configured to receive truck sensor data of a truck, wherein the truck is configured to tow the trailer. The trailer further comprises: - a trailer yaw rate estimator as defined above; - an environmental sensor, in particular a radar sensor, comprising an input port for the yaw rate provided by the yaw rate estimator.

[0014] The received truck sensor data can be used for the yaw rate estimation itself or for optimizing an already existing yaw rate estimation result.

[0015] The environmental sensor can use the yaw rate for environmental perception functions, e.g. determining the current driving direction.

[0016] Optionally, the trailer is one of the following types: a turntable trailer, a semi-trailer, a tag axle trailer. Further embodiments relate to a method for estimating the yaw rate of a trailer in a vehicle combination. The vehicle combination comprises a truck and a trailer, and at least one sensor for providing sensor data characterizing the yaw rate of the trailer. The method comprises the following steps: estimating, by a data processing unit of an estimator, the yaw rate of the trailer based on the provided sensor data. The sensor data comprises at least one of the following: - a rotational speed value of one or more trailer wheels; - a steering angle of the truck; - a steering angle of the trailer; - an articulation angle between the trailer and the truck; - at least one parameter defining the wheelbase of the trailer; - at least one parameter defining the track width of the trailer; - at least one parameter defining the wheelbase of the truck; - at least one parameter defining the track width of the truck.

[0017] The method or at least parts of the steps thereof can also be implemented by a software or computer program product. In particular, embodiments of the present disclosure can be implemented by a software or software module installed in an electronic control unit (ECU). Embodiments of the present disclosure therefore also relate to a computer program or a computer readable storage means having a program code stored therein, which program code, when executed on a processor, e.g. on an estimator as defined above, is adapted to perform the above described method.

[0018] Embodiments of the present disclosure solve the above-mentioned problems with trailers by providing an estimator specifically designed for installation on a trailer, and a method for estimating the yaw rate of a trailer, a semi-trailer vehicle combination or a tag axle trailer. According to embodiments of the present disclosure, the yaw rate of a trailer or semi-trailer vehicle combination can be estimated or determined using existing sensors. Such available sensors include wheel speed sensors, steering angle sensors, articulation angle detection sensors and other types of sensors.

[0019] According to embodiments of the present disclosure, the yaw rate estimation is divided into two different scenarios: (a) the input data of the utilized sensors is simultaneously from the truck and the trailer; (b) the input data of the utilized sensors is only from the trailer.

[0020] Embodiments of the present disclosure encompass both scenarios as described above. BRIEF DESCRIPTION OF DRAWINGS

[0021] Some system and / or method embodiments will hereinafter be described in conjunction with the appended drawings, by way of example, in which: Figure 1 Structure diagram of a trailer yaw rate estimator according to an embodiment of the present disclosure. Figure 2 Detailed structure diagram of a trailer yaw rate estimator according to an embodiment of the present disclosure. Figure 3 Flow diagram of a trailer yaw rate estimation method according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0022] Figure 1 Structure diagram of a trailer yaw rate estimator according to an embodiment of the present disclosure. The trailer 10 is towed by a truck 20 via a coupling 30 (kingpin). The trailer 10 can be equipped with one or more trailer sensors 15. The truck 20 can be equipped with one or more truck sensors 25. The trailer sensors 15 and / or the truck sensors 25 provide corresponding sensor data 115, 125, wherein at least part of the data is used for estimating a yaw rate 50 of the trailer 10. The estimator 100 comprises a data processing unit configured to estimate the yaw rate 50 of the trailer 10 based on the provided sensor data 115, 125. The provided sensor data 115, 125 comprises at least one of: - a rotational speed value of one or more wheels of the trailer 10; - a steering angle 70 of the truck 20; - a steering angle of the trailer 10 (e.g. in case of a non-semitrailer trailer); - a hitch angle 60 between the trailer 10 and the truck 20.

[0023] In the present disclosure, the term “trailer” also includes semitrailers, center-axle trailers and other vehicles that can be towed by a towing vehicle. The term “yaw rate” can be defined as the angular velocity around a vertical axis, which characterizes the turning angular velocity of the trailer 10 at a certain time. Obviously, this physical quantity is closely related to the hitch angle 60 or the steering angle 70, in combination with the rotational speed of the wheels of the trailer 10. In particular, the rotational speed values of the wheels on both sides of a non-steering axle can be used to determine the turning condition or the turning radius, e.g. based on the rotational speed difference of the wheels on both sides. Furthermore, the rotational speed values of the wheels can also be used to determine the lateral speed of the trailer / vehicle, regardless of whether the trailer / vehicle is driving along a curve or along a straight line. Therefore, based on the rotational speed difference of the wheels on both sides only, the rate of change of the direction of the trailer, i.e. the yaw rate, can be directly determined.

[0024] Thus, if the above data is available, the yaw rate 50 of the trailer 10 can be calculated or at least estimated. It is appreciated that not all sensor data is required. With only a part of the sensor data, a rough estimate of the yaw rate 50 can be obtained. This estimate can then be further refined by supplementing the optional sensor data 115, 125.

[0025] Further, the estimate can be further refined using one or more parameters 116, 118, 119, 126, as will be described below.

[0026] Figure 2 A detailed structure diagram of further embodiments of the present disclosure is shown. The input parameters of the yaw rate estimator 100 are divided into two categories, one is the sensor data 115, 127, and the other is the parameters 117, 127. These parameters are from other sources and are used to define the non-dynamic characteristics of a specific trailer 10 or a specific truck 20.

[0027] The parameters 117, 127 include one or more trailer (geometric) parameters 117 and / or one or more truck (geometric) parameters 127. The parameters 117, 127 can include all available geometric parameter data of the truck 20 and / or the trailer 10. For example, the geometric parameters 117 of the trailer 10 can include (see Figure 1 ): the wheel width 116, one or more wheel base or track 118, the kingpin reference 119, i.e. the distance of the coupling between the trailer 10 and the truck 20. The geometric parameters 127 of the truck 20 can include: the wheel width 126, one or more wheel base or track 128, the position of the trailer coupling 30. Other parameters can also include the weight or size (length, width, height) of the trailer and / or the truck, the number of wheels, the number of axles. According to embodiments of the present disclosure, the yaw rate estimator 100 can retrieve these parameters from other vehicle components, such as a memory or an electronic control unit. Alternatively or additionally, these parameters can be stored locally to the estimator 100. Thus, the estimator 100 can comprise a data storage for storing at least part of the above-mentioned parameters 117, 127. These parameters 117, 127 can further improve the accuracy of the estimate. For example, the smaller the wheel width, the greater the yaw rate 50 when the difference in rotational speed of the wheels on both sides of the trailer 10 is the same, and vice versa.

[0028] However, the yaw rate estimator 100 can also rely only on the sensor data 125 provided by the truck 20 and the sensor data 115 provided by the trailer 10 for the estimation, in which case the dependence on information provided by the trailer 10 can be reduced. For example, the truck 20 can provide the steering angle 70 and / or the articulation angle 60. In combination with at least one wheel rotational speed value provided by the wheel rotational speed sensor 15 on the trailer 10, it is sufficient to accurately determine the yaw rate 50 acting on the trailer 10.

[0029] On the other hand, when only trailer sensor data 115 is available, i.e. only data provided by sensors 15 mounted on the trailer 10, an accurate estimation of the yaw rate 50 can require the trailer 10 to be equipped with multiple sensors 15. For example, wheel speed sensors 15 can be mounted on the left and right side (or on all wheels) of the trailer. As mentioned before, the yaw rate 50 can be estimated by processing at least two wheel speed values, for example the wheel speed values of two wheels on the same non-steering axle. This is because the rate of change of direction of the trailer 10 corresponds to the difference in wheel speed of the wheels on the left and right side of the trailer 10. If the wheel speed on the left side is the same as the wheel speed on the right side, it can be concluded that the trailer 10 is driving in a straight line, i.e. the yaw rate 50 is zero.

[0030] For a particular curve, the yaw rate 50 depends on the longitudinal speed of the vehicle through the curve. Therefore, the estimator 100 can also optimize the estimation result based on the vehicle speed of the trailer 10. The vehicle speed of the trailer 10 can be obtained by averaging the wheel speed values on both sides. Thus, the estimation of the yaw rate 50 can be achieved even if no information is available from the truck 20, for example if no data connection is available. The trailer 10 can autonomously perform the estimation of the yaw rate 50. Figure 3 A flowchart of a method for estimating the yaw rate of a trailer in a vehicle combination comprising a truck 20 and a trailer 10 is shown. The method comprises the following steps: - obtaining S110 sensor data 115, 125 provided by at least one environmental sensor mounted on the trailer 10 and / or the truck 20; - estimating S120 the yaw rate 50 of the trailer 10 based on the sensor data 115, 125.

[0031] The sensor data can comprise any of the parameters mentioned above. Furthermore, the method can be performed by the data processing unit of the estimator 100 mounted on the trailer 10 as described before.

[0032] The method can also be implemented by a computer. It will be clear to the skilled person that the individual steps of the method described above can be performed by a programmable computer. Embodiments of the disclosure are also intended to encompass program storage devices, such as digital data storage media. The program storage devices can be machine or computer readable media which store programs of machine executable or computer executable instructions. The programs of machine executable or computer executable instructions, when executed on a computer or processor, perform some or all of the steps of the method described above.

[0033] The gist of the embodiments of the disclosure is summarized as follows: - a method for estimating the yaw rate of a vehicle, in particular a trailer 10, which can utilize vehicle dynamics input signals 115 of the trailer 10 and its towing vehicle 20; - the method for estimating the yaw rate of a vehicle can utilize the steering angle 70 of the truck 20; - The vehicle yaw rate estimation method can utilize the hitch angle 60 between the trailer 10 and the towing vehicle 20; - The vehicle yaw rate estimation method can utilize the wheel speed on the non-steered axle (e.g. non-steered bogie axle) of the trailer 10; - The vehicle yaw rate estimation method can utilize the truck wheel base, kingpin offset and trailer wheel base, track etc. geometry parameters; - The vehicle yaw rate estimation method can utilize only vehicle dynamic input signals of a specific trailer 10; - The vehicle yaw rate estimation method can utilize the wheel speed on the non-steered axle (e.g. non-steered bogie axle) of the trailer 10; - The vehicle yaw rate estimation method can utilize the wheel speed on both sides of the same axle of the trailer; - The vehicle yaw rate estimation method can utilize the truck wheel base, kingpin offset and trailer wheel base, track etc. geometry parameters.

[0034] The geometry parameters describe not only the wheel base, track etc. parameters of the vehicle (towing vehicle or trailer), but also the kingpin offset for the estimation of the yaw rate, as well as the trailer wheel base and the trailer wheel base.

[0035] The specification and drawings merely illustrate the principles of the disclosure. It will be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the disclosure and are included within its spirit and scope.

[0036] Furthermore, each embodiment can stand alone as an exemplary technical solution. It should be noted that in other embodiments, the defined features can be combined differently, i.e. a specific feature described in one embodiment can also be implemented in other embodiments. Unless it is explicitly stated that a specific combination is not within the protection scope of the disclosure, such combinations are all protected by the disclosure.

[0037] List of reference signs 10 trailer (towed vehicle) 20 truck (towing vehicle) 15 sensor mounted on the trailer (trailer sensor) 25 sensor mounted on the truck (truck sensor) 30 trailer-truck coupling (kingpin, drawbar) 50 yaw rate 60 hitch angle 70 steering angle 100 yaw rate estimator 115 sensor data of the trailer sensor 117 (geometric) parameters of the trailer 118 trailer wheel base 119 distance between kingpin and trailer axle 125 sensor data of truck sensors 127 (geometric) parameters of truck 128 track 116, 126 wheel width (trailer, truck)

Claims

1. A trailer yaw rate estimator (100), wherein, The trailer (10) and the truck (20) constitute a vehicle assembly, the vehicle assembly having one or more sensors (15, 25) for providing sensor data (115, 125) characterizing the yaw rate (50) of the trailer (10), characterized in that, The estimator includes a data processing unit configured to estimate the yaw rate (50) of the trailer (10) based on provided sensor data (115, 125), wherein the sensor data (115, 125) includes at least one of the following: - The rotational speed of one or more wheels of the trailer (10); - The steering angle (70) of the truck (20); - The steering angle of the trailer (10); - The hinge angle (60) between the trailer (10) and the truck (20); - The yaw rate of the truck (20); - The speed value of the truck (20).

2. The estimator according to claim 1, characterized in that, The data processing unit is also configured to further refer to at least one of the following parameters (117, 127) when estimating the yaw rate (50) or optimizing the estimation result of the yaw rate: - Parameter (117) characterizing the wheelbase of the trailer (10). - Parameter (117) characterizing the wheelbase of the trailer (10); - Parameter (127) characterizing the wheelbase of the truck (20); - Parameter (127) characterizing the wheelbase of the truck (20); - A parameter that defines the position of the coupling portion (30) between the trailer (10) and the truck (20).

3. The estimator according to claim 1 or 2, wherein, The one or more sensors (15, 25) include a plurality of trailer sensors (15) mounted on the trailer (10), characterized in that, The data processing unit is configured to estimate the yaw rate (50) solely based on trailer sensor data (115) provided by a plurality of sensors (15) mounted on the trailer (10), the trailer sensor data (115) including at least one of the following: - The wheel speed values ​​of two trailer wheels mounted on both sides of the same trailer axle; - The hinge angle (60) between the trailer (10) and the truck (20) is combined with one of the wheel speed values ​​of the trailer wheels.

4. The estimator according to claim 1 or 2, wherein, The one or more sensors (15, 25) include a plurality of truck sensors (25) mounted on the truck (20), characterized in that, The data processing unit is configured to estimate the yaw rate (50) based solely on truck sensor data (125) provided by a plurality of sensors (25) mounted on the truck (20), the truck sensor data (125) including at least one of the following: - The yaw rate value of the truck (20); - The wheel speed value of at least one wheel of the truck (20) combined with the steering angle (70); - The wheel speed value of at least one wheel of the truck (20) combined with the hinge angle (60) between the trailer (10) and the truck (20). - The longitudinal speed of the truck (20) is combined with the steering angle (70) or the articulation angle (60).

5. The estimator according to claim 1 or 2, wherein, The one or more sensors (15, 25) include at least one truck sensor (25) mounted on the truck (20) and at least one trailer sensor (15) mounted on the trailer (10), characterized in that, The data processing unit is configured to estimate the yaw rate (50) based on a combination of truck sensor data (125) provided by the at least one truck sensor (25) and trailer sensor data (115) provided by the at least one trailer sensor (15), wherein the combination of sensor data includes at least one of the following: - The steering angle (70) of the truck (20) and the wheel speed of one wheel of the trailer (10); - Wheel speed values ​​of multiple wheels of the truck (20) and / or the trailer (10).

6. A trailer (10) with a trailer sensor (15), characterized in that, The trailer includes: - Trailer yaw rate estimator (100) according to any one of the preceding claims; and - An environmental sensor, particularly a radar sensor, which includes an input port for the yaw rate provided by the yaw rate estimator (100).

7. The trailer (10) according to claim 6, wherein the trailer (10) is configured to receive truck sensor data (125) from the truck sensor (25), wherein, The truck (20) is configured to tow the trailer (10), characterized in that, The yaw rate estimator (100) is configured to estimate the yaw rate (50) using the truck sensor data (125), or to optimize existing yaw rate estimation results.

8. The trailer (10) according to claim 6 or 7, characterized in that, The trailer is one of the following: a steering trailer, a semi-trailer, or a center-axle trailer.

9. A method for estimating the yaw rate of a trailer (10) in a vehicle combination, wherein, The vehicle assembly includes a truck (20), a trailer (10), and sensors (15, 25) for providing sensor data (115, 125) characterizing the yaw rate (50) of the trailer (10), characterized in that the method includes the following steps: The data processing unit estimates (S120) the yaw rate of the trailer (10) based on the provided sensor data (115, 125), wherein the sensor data (115, 125) includes at least one of the following: - The wheel speed value of one or more trailer wheels; - The steering angle of the truck (20); - The steering angle of the trailer (10); - The hinge angle (60) between the trailer (10) and the truck (20); - One or more parameters that limit the trailer wheelbase (118, 119). - One or more parameters of the trailer wheel track (118, 119). - One or more parameters (128) of the wheelbase of the truck (20). - One or more parameters (128) of the wheelbase of the truck (20).

10. A computer-readable storage device having software code stored thereon, wherein when the program code is run on a processor, the software code is designed to manipulate a data processing unit to perform the method for estimating yaw rate according to claim 9.

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