A method and a control arrangement for estimation of motion of a portion of a vehicle body, and methods and control arrangements for motion compensation, detection of a critical situation and detection of a miscalibration of sensors

Abstract

A method (200) performed by a control arrangement (500) for estimation of motion of a portion (120, 130) of a vehicle body mounted on a chassis (110) of a vehicle (100) is presented. The method comprises: - measuring (210), for the vehicle (100) in use, at least three distances (155a, 155b, 155c) between the portion (120, 130) and the chassis (110), the at least three distances (155a, 155b, 155c) being measured between at least four distance sensors (151a, 151b, 151c, 153a, 153b, 153c, 152a, 152b, 152c), wherein one of the portion (120, 130) and the chassis (110) comprises at least three distance sensors (152a, 152b, 152c) and the other one of the portion (120,130) and the chassis (110) comprises at least one distance sensor (151a); - determining (220), based on the measured at least three distances (155a, 155b, 155c), a position (P) of the portion (120, 130) relative to the chassis (110); and - estimating (230) a motion of the portion (120, 130) of the vehicle body relative to the chassis (110) based on the determined position (P).

Description

[0001] A METHOD AND A CONTROL ARRANGEMENT FOR ESTIMATION OF MOTION OF A PORTION OF A VEHICLE BODY, AND METHODS AND CONTROL ARRANGEMENTS FOR MOTION COMPENSATION, DETECTION OF A CRITICAL SITUATION AND DETECTION OF A MISCALIBRATION OF SENSORS

[0002] Technical field

[0003] The invention relates to a method and a control arrangement for estimation of motion of a portion of a vehicle body. The invention also relates to methods and corresponding control arrangements for motion compensation, detection of a critical situation and detection of a sensor miscalibration. The invention also relates to a vehicle comprising such a control arrangement, and to a computer program and a computer-readable medium carrying out the methods.

[0004] Background

[0005] The following background description constitutes a description of the background to the invention, which does not, however, necessarily have to constitute prior art.

[0006] Vehicles of today, for example heavy vehicles such as a trucks, are often equipped with one or more system sensors. For example, cameras, light detection and ranging (LIDAR) sensors and / or radar equipment may be used in vehicles to determine where the vehicle is positioned and / or in which direction it is moving. Such system sensors are for example used in applications for autonomous vehicles, where their accuracy is especially important. Such system sensors may also be used for support systems in driver-controlled vehicles.

[0007] The system sensors are mounted in various locations on the vehicle. Typically, the system sensors are mounted where they have a clear view of the surroundings of the vehicle, such as e.g. on the driver cabin of a truck. For example, the roof and / or the comers of the cabin are common places for attaching such system sensors looking in the forward and side directions of the vehicle. System sensors looking backwards and / or sideways may be mounted on a load receiving arrangement of the truck, also known as the truck bed or the bucket of the truck. Also, system sensors may be mounted on the chassis of the vehicle. A vehicle conventionally comprises a suspension system in order to provide comfort for the driver in the cabin, and to protect the transported load from road vibrations and road bumps, when the vehicle is in movement / motion, i.e. is travelling along a road. Because of the suspension, the cabin and / or the load receiving arrangement of the vehicle may be moving slightly differently from the chassis of the vehicle, i.e. from the rest of the vehicle, when the vehicle is in use.

[0008] The cabin and the load receiving arrangement may thus, since they are suspended from the chassis of the vehicle, differ in motion compared to the motion of the chassis, i.e. compared to the rest of the vehicle. This may also be expressed as the cabin and load receiving arrangement frames, respectively, may move at least partially independently in relation to the vehicle / chassis frame when the vehicle is in motion. As mentioned above, system sensors are often mounted on the cabin and / or the load receiving arrangement, since it is advantageous to mount them where they have a clear view of the surroundings. System sensors mounted on the cabin and / or the load receiving arrangement will, due to the suspension, move slightly independently from the chassis when the vehicle is in movement / motion, and will therefore also differ in motion from system sensors mounted on the chassis. Also, when the vehicle is in use for tipping / tilting the load receiving arrangement, the sensors mounted on the load receiving arrangement will move differently than the sensors mounted on the chassis. The different motion of the system sensors mounted on the cabin, and / or the load receiving arrangement, relative to the system sensors mounted on the chassis may cause problems for the systems utilizing information from these system sensors, such as e.g. autonomous vehicle control systems or driver support systems.

[0009] It is an objective of the present invention to provide a solution mitigating or solving drawbacks of conventional solutions. One objective of the present invention is to provide a solution for estimating a motion of a portion of the vehicle body, for example the cabin and / or the load receiving arrangement. According to a first aspect of the invention, aforementioned and further objectives are achieved through a method to be performed by a processing arrangement for estimation of motion of a portion of a vehicle body mounted on a chassis of a vehicle, the method comprising:

[0010] - measuring, for the vehicle in use, at least three distances between the portion and the chassis, the at least three distances being measured between at least four distance sensors, wherein one of the portion and the chassis comprises at least three distance sensors and the other one of the portion and the chassis comprises at least one distance sensor;

[0011] - determining, based on the measured at least three distances, a position of the portion relative to the chassis; and

[0012] - estimating a motion of the portion of the vehicle body relative to the chassis based on the determined position.

[0013] In autonomous vehicles and / or in vehicles comprising driver support systems, system sensors providing these systems with information are often installed on the cabin and / or on the load receiving arrangement, i.e. on a portion of the vehicle body. Due to the suspension system between the cabin and load receiving arrangement and the chassis, respectively, the portion of the vehicle body is moving in relation to the chassis when the vehicle is in movement / motion, i.e. is travelling along a road. Also, during tilting of the load receiving arrangement, the load receiving arrangement is moving in relation to the chassis. The vehicle being in use for tilting the load receiving arrangement may also be seen as the vehicle being in tiling motion, which may take place at standstill. Thus, in this document, the vehicle being in use includes both the vehicle moving forward, and the vehicle standing still and tilting the load receiving arrangement. Thanks to the presented method, the movement of the portion relative to the vehicle chassis may be estimated. This estimation of the relative movement is especially important when additional system sensors are attached to the chassis. The method makes it possible to, for example, align measurements performed by the system sensors mounted on the portion of the vehicle body with measurements performed by system sensors mounted on the chassis. Hereby, the sensor information from the vehicle body portion frame may be transformed to sensor information from the rest of the vehicle, i.e. from the chassis frame, and vice versa. The presented method utilizes direct distance measurements between vehicle mounted distance sensors for estimation of the motion of the vehicle body portion. Such direct distance measurements between vehicle mounted distance sensors may communicate with each other and are very accurate. Further, the distance sensors are low at cost and may be battery driven to have a long lifetime. The distance sensors are also easy to mount on the portion and / or chassis, e.g. by magnets. The distance sensors also have a limited need for maintenance.

[0014] To base the motion estimation on measurements utilizing vehicle mounted distance sensors communicating with each other is less complex than conventional solutions and eliminates a number of possible error sources being caused by for example other vehicles, cliffs, buildings, other roads and / or tunnels. For example, the herein presented motion estimation is possible to execute with high accuracy and low latency in tunnels, which is not possible for conventional solutions.

[0015] Thus, a quick, accurate, low-cost and low complexity motion estimation of the vehicle body portion is provided, which is crucial for providing reliable and precise perception and localization of the vehicle based on system sensor information e.g. when the vehicle is controlled autonomously.

[0016] In an embodiment of the invention, the estimation of the motion of the portion is based also on a reference position of the portion.

[0017] The reference position of the portion, for example a cabin or a load receiving arrangement of the vehicle, is a position the portion has when the portion does not move in relation to the chassis, preferably at rest of the vehicle. The reference position may for example be determined based on the design of the vehicle and / or may be known from the assembly / manufacturer line when the vehicle is built. The determination of the reference position may also take suspension system settings and / or component wear into consideration. The reference position may alternatively be determined by utilization of the herein described measured distances between the distance sensors .

[0018] In an embodiment of the invention, the estimation of the motion comprises:

[0019] - determining a displacement of the portion from the reference position to the position; and

[0020] - estimating the motion of the portion relative to the chassis based on the determined displacement.

[0021] To estimate the motion of the portion relative to the chassis based on the displacement utilizes the determined reference position as a basis for the estimation of the motion of the portion in relation to the chassis. Hereby, also the displacement from the reference position may be easily determined. The displacement of the portion is associated with the relative motion of the portion, and may intuitively be understood as an indication of the motion.

[0022] In an embodiment of the invention, the reference position is determined as one in the group of:

[0023] - based on known dimensions of the vehicle;

[0024] - the position of the portion determined for the vehicle at rest; and

[0025] - based on two or more positions determined for the vehicle at rest.

[0026] The reference position may hereby be determined in a number of ways. If the dimensions, suspension system settings and / or component wear are known, for example if the distance sensors are mounted by the manufacturer or by another party having access to detailed dimension data for the vehicle, the reference position may be easily calculated. Otherwise, the reference position may be determined by utilization of the herein described distance sensors and measured distances between the distance sensors. If measurements of the distance sensors are used for determining the reference position, more than one measurements may be taken into account, for example by averaging, such that the reliability of the determination is increased.

[0027] In an embodiment of the invention, the estimation of the motion further comprises:

[0028] - determining, for the vehicle in use, an orientation of the at least one distance sensor of the portion; and

[0029] - estimating the motion of the portion relative to the chassis further based on the determined orientation. The determined orientation of the at least one distance sensor may hereby be utilized as a basis for a confirmation of that the estimation of the motion of the portion is correct. Hereby, an improved robustness is achieved, since a check of if the displacement determined based on distance measurements by the distance sensors is correct is provided.

[0030] In an embodiment of the invention, the orientation is determined based on one in the group of:

[0031] - distance measurements between the portion and the chassis measured by at least three distance sensors of the portion and at least three distance sensors of the chassis; and

[0032] - inertial measurement unit information provided by the at least one distance sensor of the portion.

[0033] The orientation of the at least one distance sensor mounted on the portion may be determined based on at least three distinct distances between the portion and the chassis between at least three distance sensors of the portion and at least three distance sensors of the chassis. Thus, the herein described distance sensors and distance measuring may be utilized for determining the orientation of the distance sensor, without adding additional hardware specifically for the orientation determination, i.e. without unnecessarily adding to the hardware complexity.

[0034] Also, the at least one distance sensor of the portion may comprise an inertial measurement unit (IMU), which then provides information associated with the inertial motion of the portion, such as e.g. angular velocities and / or translational accelerations. Hereby, the orientation of the at least one distance sensor mounted on the portion may be reliably and easily be determined based on the provided inertial measurement unit information.

[0035] In an embodiment of the invention, a triangulation based on the at least three measured distances is utilized for determining one or more in the group of:

[0036] - the position of the portion; and

[0037] - an orientation of the at least one distance sensor of the portion. By utilizing triangulation, the position of the portion and / or the orientation of the at least one portion mounted distance sensor may be determined without adding more hardware than the distance sensors, which reduces the hardware complexity.

[0038] In an embodiment of the invention, the portion of the vehicle body comprises one or more in the group of:

[0039] - a cabin of the vehicle; and

[0040] - a load receiving arrangement of the vehicle.

[0041] System sensors mounted on the cabin provide a clear view of the surroundings of the vehicle, such as e.g. in the forward and side directions of the vehicle. System sensors mounted on a load receiving arrangement of the truck provide a clear view e.g. backwards and / or sideways from the vehicle. To attach system sensors providing information to systems for autonomous driving and / or driver support on the cabin and / or the load receiving arrangement therefore secures that reliable and high quality sensor information is provided to these systems. The herein presented motion estimation may therefore improve the quality and reliability of the provided sensor information.

[0042] In an embodiment of the invention, the at least one distance sensor of the portion is attached according to one or more in the group of:

[0043] - on a roof of a cabin;

[0044] - at one or more comers of a cabin;

[0045] - at one or more sensors utilized by an autonomous system of the vehicle.

[0046] By attaching the distance sensors in or close to locations where the systems sensors are normally mounted results in a motion estimation for the same or corresponding locations where the system sensors are mounted. Such a motion estimation especially performed for the specific locations of the system sensors may be utilized for exact compensation of the sensor information provided by the system sensors. Hereby, the quality and reliability of the autonomous systems and / or driver support systems is improved. Also, to attach the distance sensors on the roof and / or comers of the cabin and / or on the load receiving arrangement guarantees that the distance sensors are not covered or obscured by other vehicle parts. In an embodiment of the invention, the at least four distance sensors are ultra wide band sensors.

[0047] Generally, ultra wide band (UWB) distance sensors / nodes use time of flight, i.e. a difference between the time of arrival and time of transmission, of radio signals to determine a distance between a transmitter node and a receiver node. Ultra wide band distance sensors may transmit relatively large amounts of data, such as e.g. identification data, time stamps and time of flight data, while consuming little transmit energy. Time of flight measurements are used for determining distances for the distance sensors with centimeter resolution. The ultra wide band distance sensors transmit and / or receive low frequency radio signals, which are able to pass through obstacles such as walls and objects, whereby the positioning accuracy is improved.

[0048] Ultra wide band sensors are accurate and low-cost friendly sensors having a long battery lifetime. They are easy to attach and detach by magnets. There is no need of cabling between the ultra wide band sensors since they create their own wireless communication system, which connects the ultra wide band sensors to each other. Only one ultra wide band sensor in this wireless communication system need to be connected, e.g. via wired and / or wireless connection, to the control arrangement / system of the vehicle. Also, there is little need for maintenance of the ultra wide band sensors. The ultra wide band sensors provide fast and accurate measurements for the vehicle body portion motion estimation to mitigate the influence of system sensor movements. Hereby, an increased reliability of the autonomous systems, such as perception or localization systems, is provided.

[0049] In an embodiment of the invention, positions of the portion relative to the chassis are repeatedly determined during use of the vehicle.

[0050] The determination of the position may for example be repeated according to a predetermined repetition scheme, or may be triggered in certain detected situations, states and / or conditions for the vehicle. Hereby, the motion of the portion may be estimated as often as necessary to capture and correct for portion motions affecting the measurements of the system sensors, whereby the quality and reliability of the autonomous and / or driver support systems are improved. According to a second aspect, a method performed by a control arrangement for motion compensation of sensor information is presented, the method comprising:

[0051] - estimating the motion of the portion of the vehicle body relative to the chassis according to any one of the herein described aspects or embodiments; and

[0052] - compensating, based on the estimated motion, sensor information provided by one or more system sensors configured on the portion of the vehicle body.

[0053] Hereby, the sensor information provided by system sensors for example mounted on the cabin is compensated such that it matches the sensor information provided by system sensors mounted on the chassis. For example, the images and / or point clouds provided by the system sensors mounted on the cabin are compensated for the portion motion such that they are aligned with corresponding images and / or point clouds provided by the system sensors mounted on the chassis. Hereby the autonomous systems and / or driver support systems are provided with more accurate information and may provide a higher lever of quality control of the vehicle and / or driver support.

[0054] According to a third aspect, a method performed by a control arrangement for detection of a critical situation is presented, the method comprising:

[0055] - estimating the motion of the portion of the vehicle body relative to the chassis according to any one of the herein described aspects or embodiments; and

[0056] - detecting a critical situation if the estimated motion exceeds a motion threshold.

[0057] By detecting a critical situation, such as for example that the vehicle is approaching potential rollover situation, the control system may control the vehicle, or may alert the driver, to maneuver the vehicle to avoid the critical situation.

[0058] According to a fourth aspect, a method performed by a control arrangement for detection of miscalibration of system sensors is presented, the method comprising:

[0059] - estimating the motion of the portion of the vehicle body relative to the chassis according to any one of the herein described aspects or embodiments; and

[0060] - detecting a miscalibration of one or more system sensors configured on the portion of the vehicle body and one or more system sensors configured on the chassis based on the estimated motion.

[0061] If e.g. the cabin is tilted due to braking, an initial calibration of the system sensors for the autonomous and / or driver support systems performed by their installation may no longer apply. The detected miscalibration between the system sensors configured on the portion and the sensors configured on the chassis may then for example be utilized for calibrating the portion mounted system sensors and the chassis mounted system sensors, such that the system information they provide is matched / aligned.

[0062] According to a fifth aspect, a control arrangement arranged for estimation of motion of a portion of a vehicle body mounted on a chassis of a vehicle is presented, the processing arrangement being configured to:

[0063] - measure, for the vehicle in use, at least three distances between the portion and the chassis, the at least three distances being measured between at least four distance sensors, wherein one of the portion and the chassis comprises at least three distance sensors and the other one of the portion and the chassis comprises at least one distance sensor;

[0064] - determine, based on the measured at least three distances, a position of the portion relative to the chassis; and

[0065] - estimate a motion of the portion of the vehicle body relative to the chassis based on the determined position.

[0066] The control arrangement according to the fifth aspect has corresponding advantages as mentioned for the method according to the first aspect.

[0067] According to a sixth aspect, a control arrangement arranged for motion compensation of sensor information is presented, wherein the control arrangement is configured to:

[0068] - estimate the motion of the portion of the vehicle body relative to the chassis, according any one of the herein described aspects or embodiments; and - compensate, based on the estimated motion, sensor information provided by one or more system sensors configured on the portion of the vehicle body.

[0069] The control arrangement according to the sixth aspect has corresponding advantages as mentioned for the method according to the second aspect.

[0070] According to a seventh aspect, a control arrangement arranged for motion compensation of sensor information is presented, wherein the control arrangement is configured to:

[0071] - estimate the motion of the portion of the vehicle body relative to the chassis, according any one of the herein described aspects or embodiments; and

[0072] - detect a critical situation if the estimated motion exceeds a motion threshold.

[0073] The control arrangement according to the seventh aspect has corresponding advantages as mentioned for the method according to the third aspect.

[0074] According to an eighth aspect, a control arrangement for detection of miscalibration of sensors is presented, wherein the control arrangement is configured to:

[0075] - estimate the motion of the portion of the vehicle body relative to the chassis, according any one of the herein described aspects or embodiments; and

[0076] - detect a miscalibration of one or more system sensors configured on the portion of the vehicle body and one or more system sensors configured on the chassis based on the estimated motion.

[0077] The control arrangement according to the eighth aspect has corresponding advantages as mentioned for the method according to the fourth aspect.

[0078] According to a nineth aspect, a vehicle comprising a control arrangement as herein described is presented.

[0079] The vehicle according to the ninth aspect has corresponding advantages as mentioned for the method according to the first aspect. According to a tenth aspect, the invention relates to a computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the herein described methods.

[0080] The computer program according to the tenth aspect has corresponding advantages as mentioned for the method according to the first aspect.

[0081] According to an eleventh, the invention relates to a computer-readable medium comprising instructions which, when executed by a computer, cause the computer to carry out the herein described methods.

[0082] The computer-readable medium according to the eleventh aspect has corresponding advantages as mentioned for the method according to the first aspect.

[0083] It will be appreciated that all the embodiments described for the method aspects of the invention are applicable also to one or more of the control arrangement aspects, the vehicle aspect, the computer program aspect and the computer-readable medium aspect of the invention. Thus, all the embodiments described for the method aspects of the invention may be performed / implemented by the herein described control arrangements, vehicle, computer program and / or the computer-readable medium.

[0084] The control arrangements may also be a processing device, i.e. a device. The control arrangement aspects, the vehicle aspect, the computer program aspect and the computer-readable medium aspect, and their embodiments, have advantages corresponding to the advantages mentioned above for the methods and their embodiments.

[0085] Brief description of the drawings

[0086] Embodiments of the invention will be illustrated in more detail below, along with the enclosed drawings, where similar references are used for similar parts, and where: Figure 1 schematically illustrates an example vehicle;

[0087] Figure 2 shows a flow chart of a method according to some embodiments;

[0088] Figures 3a-b schematically show an example of a moving / tilting cabin;

[0089] Figure 4 schematically shows an example cabin and chassis of a vehicle; Figure 5 shows a flow chart of a method according to some embodiments;

[0090] Figure 6 shows a flow chart of a method according to some embodiments; Figure 7 shows a flow chart of a method according to some embodiments;

[0091] Figure 8 shows a control unit / processing arrangement, in which a method according to any one of the herein described embodiments may be implemented.

[0092] Detailed description

[0093] Figure 1 schematically shows an exemplary heavy vehicle 100, such a truck of some kind, which will be used to explain the herein presented aspects and embodiments. The aspects and embodiments are, however, not limited to use in vehicles as the one shown in figure 1 , but may also be used in other vehicles.

[0094] The example vehicle 100 shown schematically in figure 1 comprises a pair of drive wheels 111 and at least one other pair of wheels 112 arranged on a chassis 110. The vehicle 100 may include essentially any number of wheels, although four wheels are illustrated in the figure. The vehicle furthermore comprises a drivetrain configured to transfer a torque between at least one power source, such as e.g. an engine and / or a motor, and the drive wheels 111. The vehicle furthermore comprises a braking system of some kind. The drivetrain, the at least one power source and the braking system are not shown in figure 1 , since only features necessary for understanding the herein described aspects and embodiments are shown for readability reasons.

[0095] The vehicle 100 also includes a cabin 120, in which a driver may at least partially control the vehicle. The vehicle 100 may further comprise a load receiving arrangement 130, which may receive a load to be carried by the truck, e.g. a load, freight, or goods of some kind. The load receiving arrangement 130 is arranged such that it may be tipped / tilted, for example to unload the load having been carried by the truck.

[0096] A suspension system 140 is coupled between the chassis 110 and the cabin 120, and between the chassis 110 and the load receiving arrangement 130. Thus, one or more suspension units 141 , 142, 143 are arranged to suspend the cabin 120 from for example road vibrations experienced by the chassis 110. Correspondingly, one or more suspension units 144, 145, 146 are arranged for providing suspension for the load receiving arrangement 130. The vehicle 100 may comprise one or more sensors 161a, 161 b, 161 c, such as for example cameras, light detection and ranging sensors and / or radar equipment, mounted on the cabin 120, herein denoted system sensors. The vehicle 100 may also comprise one or more such system sensors 163a, 163b, 163c mounted on the load receiving arrangement 130. The vehicle 100 may also comprise one or more such system sensors 162a, 162b, 162c mounted on the chassis 110 of the vehicle.

[0097] As mentioned above, due to the suspension system 140, the cabin 120 and the load receiving arrangement 130 may move differently than the chassis 110 when the vehicle is in motion, i.e. is travelling on the road, and / or during tipping / tilting of the load receiving arrangement 130. Thus, the cabin 120 and / or the load receiving arrangement 130 may move relative to the chassis 110, respectively, since they are suspended from the chassis by the suspension system 140 and / or if the load receiving arrangement 130 is deliberately tilted. Therefore, the one or more system sensors 161a, 161 b, 161c, such as cameras, light detection and ranging sensors and / or radar equipment, mounted on the cabin 120 may, when the vehicle is in motion, move relative to the chassis, and may thus move relative to the one or more such system sensors 162a, 162b, 162c mounted on the chassis 110.

[0098] Correspondingly, the one or more system sensors 163a, 163b, 163c mounted on the load receiving arrangement 130 may, when the vehicle is in motion and / or when the load receiving arrangement 130 is tilted, also move relative to the one or more such system sensors 162a, 162b, 162c mounted on the chassis 110. For example, road bumps, braking and / or turning may cause different degrees of movements of the cabin and / or the load receiving arrangement 130 in relation to the chassis 110 due to the suspension system 140. For example, the cabin 120 may move up to 7 degrees in relation to the chassis 110 because of braking and / or road bumps.

[0099] Therefore, the sensor information, possibly comprising images, point clouds and / or other types of information, being provided by the one or more system sensors 161a, 161 b, 161c mounted on the cabin 120 and / or provided by the one or more system sensors 163a, 163b, 163c mounted on the load receiving arrangement 130 does not match the sensor information provided by the one or more system sensors 162a, 162b, 162c mounted on the chassis 110. For example, if the vehicle is braked and / or turned, the cabin 120 and / or load receiving arrangement 130 may be correspondingly tilted and / or rolled in relation to the chassis 110. Images and / or point clouds provided by the one or more system sensors 161a, 161 b, 161c mounted on the cabin 120 and / or by the one or more system sensors 163a, 163b, 163c mounted on the load receiving arrangement 130 will be therefore also be tilted and / or rolled in relation to the chassis 110 and thus also in relation to corresponding images and / or point clouds provided by the one or more system sensors 162a, 162b, 162c mounted on the chassis 110.

[0100] Thus, images and / or point clouds provided by the one or more system sensors 161a, 161 b, 161c mounted on the cabin 120 and the one or more system sensors 162a, 162b, 162c mounted on the chassis 110, respectively, may be mismatched / unaligned / non-synchronized due to the tilting and / or rolling cabin 120. Correspondingly, images and / or point clouds provided by the one or more system sensors 163a, 163b, 163c mounted on the load receiving arrangement 130 and the one or more system sensors 162a, 162b, 162c mounted on the chassis 110, respectively, may also be mismatched / unaligned / non-synchronized due to the movements of the load receiving arrangement 130 relative the chassis 110. Therefore, because of road bumps, braking and / or turning, the movements of the vehicle body portion 120, 130 will result in the provided sensor information, such as e.g. point clouds or images, being tilted and / or rolled correspondingly, depending on the maneuver.

[0101] Such mismatched / unaligned / non-synchronized sensor information degrades the accuracy of the sensor information, and may result in misleading information and incorrect decisions. For example, a cabin mounted system sensor 161a, 161 b, 161c and a chassis mounted system sensor 162a, 162b, 162c may determine differing distances to an obstacle on the road due to the movements of the cabin 120 in relation to the chassis 110. Such inaccurate and / or misleading information may cause problems for systems 300 utilizing this sensor information. Such systems 300 may comprise one or more autonomous driving systems, such as autonomous navigation systems, and / or driver support systems. Such autonomous and / or support systems 300 rely on high quality information for being able to make correct real time decisions. Figure 2 shows a flow chart for a method 200 to be performed by a processing arrangement 500 according to some aspects and embodiments. The method estimates motion of a portion 120, 130 of a vehicle body mounted on a chassis 110 of a vehicle 100.

[0102] In a first step 210, at least three distances 155a, 155b, 155c between the portion 120, 130 and the chassis 100 are measured for the vehicle 100 in use / movement / motion. The at least three distances 155a, 155b, 155c are here measured between at least four distance sensors 151a, 151 b, 151c, 153a, 153b, 153c, 152a, 152b, 152c, wherein one of the portion 120, 130 and the chassis 110 comprises at least three distance sensors and the other one of the portion 120 ,130 and the chassis 110 comprises at least one distance sensor.

[0103] For example, the at least three distances 155a, 155b, 155c may be measured between each one of at least three distance sensors 152a, 152b, 152c arranged / attached on the chassis 110 and at least one distance sensor 151a arranged / attached on the cabin 120, as schematically illustrated in figure 4, and explained more in detail below. Correspondingly, the at least three distances 155a, 155b, 155c may also be measured between each one of at least three distance sensors 151a, 151 b, 151c arranged / attached on the cabin 120 and at least one distance sensor 152a arranged / attached on the chassis 110. Hereby, a motion of the cabin 120 may be determ ined / estimated.

[0104] Also, corresponding measurements of at least three distances 155a, 155b, 155c may of course be measured between each one of the at least three distance sensors 152a, 152b, 152c arranged / attached on the chassis 110 and at least one distance sensor 153a arranged / attached on the load receiving arrangement 130, and / or may be measured between each one of at least three distance sensors 153a, 153b, 153c arranged / attached on load receiving arrangement 130 and at least one distance sensor 152a arranged / attached on the chassis 110.

[0105] In a second step 220, a position P of the portion 120, 130 relative to the chassis 110 is determined based on the measured at least three distances 155a, 155b, 155c. In a third step 230, a motion of the portion 120, 130 of the vehicle body relative to the chassis 110 is estimated 230 based on the determined position P of the portion 120, 130.

[0106] Thus, a relative position P for the portion 120, 130 of the body, where the relative position P is in relation to the chassis 110, is determined based on the measured distances. Based on the determined relative position P, the motion of the portion 120, 130 is thereafter determined / estimated.

[0107] According to an embodiment, the position P of the portion 120, 130 relative to the chassis is repeatedly determined 220 during use / movement / motion of the vehicle 100, such that the the motion of the portion 120, 130 may also be repeatedly estimated 230 when the vehicle is moving. The determination 220 of the position and / or the estimation 230 of the motion may be repeated as often as necessary, with an interval having a need-based length or a predetermined length. The determination 220 of the position and / or the estimation 230 of the motion may also be repeated in certain situations, e.g. may be triggered by certain detected situations, states and / or conditions for the vehicle 100.

[0108] According to an embodiment, schematically illustrated in figure 1 , one or more of the distance sensors 151 a, 151 b, 151c, 152a, 152b, 152c, 153a, 153b, 153c are mounted / installed at, for example attached on, the system sensors 161a, 161 b, 161 c, 162a, 162b, 162c, 163a, 163b, 163c used by the autonomous and / or driver support systems. Hereby, the nominal relative positions of the distance sensors 151 a, 151 b, 151 c, 152a, 152b, 152c, 153a, 153b, 153c are known due to the fact that the chassis 110, the cabin 120, the load receiving arrangement 130, and their attached system sensors, respectively, are mounted in well-defined positions in the manufacturer / assembly line.

[0109] According to various embodiments, the at least one distance sensor 151 a, 151 b, 151 c on the cabin 120 is attached on a roof 121 of the cabin 120 and / or at one or more comers 122 of the cabin 120, as schematically illustrated in figure 1 . Correspondingly, the at least one distance sensor 153a, 153b, 153c on the load receiving arrangement 130 may, according to some embodiments, be attached on the top 131 and / or sides of the load receiving arrangement 130, and / or at one or more comers of the load receiving arrangement 130. Hereby, the one or more distance sensors 151 a, 151 b, 151 c on the cabin 120 and / or the one or more distance sensors 153a, 153b, 153c on the load receiving arrangement 130 are not obscured / occluded / covered such that distance measurements may be safely and reliably performed.

[0110] According to an embodiment, the distance sensors 151a, 151 b, 151 c, 153a, 153b, 153c, 152a, 152b, 152c are ultra wide band sensors. Such ultra wide band sensors utilize time of flight (ToF) for measuring the distances between two ultra wide band sensors by multiplying the time of flight of the signal by the speed of light. The ultra wide band sensors provide sub-centimeter accuracy, such that accurate distance measurements are provided. The ultra wide band sensors may communicate with each other while performing the measurements, resulting in a robust measurement system. Such ultra wide band sensors are further low at cost, and provide high accuracy and low latency.

[0111] According to an embodiment, schematically illustrated in figures 3a-b, the motion of the portion 120, 130 of the vehicle body may be estimated based also on a reference position Pref of the portion 120, 130. Then, a displacement D of the portion 120 ,130 from the reference position Pref to the position P is determined 231. The motion of the portion 120, 130 may then be estimated 232 based on the determined displacement D.

[0112] The reference position Pref may be determined based on known dimensions of the vehicle 100. Since the measures / size of each part of the vehicle are known when the vehicle is produced, e.g. at the assembly / manufacturer line, and / or since it is known where the distance sensors 151 a, 151 b, 151 c, 152a, 152b, 152c, 153a, 153b, 153c are attached / mounted, the reference position may be determined / calculated, possibly by tanking current suspension system settings and / or component wear into consideration.

[0113] Alternatively, the reference position Pref may be determined as an earlier determination of the position P of the portion 120, 130, performed by utilizing the herein described at least three distances 155a, 155b, 155c being measured between the at least four distance sensors 151a, 151 b, 151c, 153a, 153b, 153c, 152a, 152b, 152c when the portion 120, 130 is non-moving, for example when the for the vehicle 100 is at rest, i.e. when the vehicle is standing still. Further, the reference position Pref may be determined based on two or more such positions P1 , P2 determined for the vehicle 100 at rest, for example as an average of the two or more determined positions P1 , P2.

[0114] Figures 3a-b schematically illustrate a side view of a vehicle 100 comprising a chassis 110 and a cabin 120. The cabin 120 is coupled to the chassis 110 by a suspension system 140, comprising one or more suspension units 141 , 142, 143. One cabin mounted distance sensor 151a and one chassis mounted distance sensor 152a are schematically illustrated, but the illustrated and explained principle may be expanded to essentially any number of distance sensors 151a, 151b, 151c, 152a, 152b, 152c on the cab 120 and the chassis 110, or to any number of distance sensors 153a, 153b, 153c, 152a, 152b, 152c on the load receiving arrangement 130 and the chassis 110.

[0115] Figure 3a illustrates the vehicle 100 when the cabin is non-moving, i.e. at standstill, or at least in non-braked situation. A first distance 155a between the cabin mounted distance sensor 151a and the chassis mounted distance sensor 152a is measured in this straight position, i.e. in the reference position Pref, of the cabin 120.

[0116] Figure 3b illustrates the vehicle e.g. at braking, when the cabin 120 is tilted in the forward direction by the suspension system 140. Thus, the lengths of the one or more suspension units 141 , 142, 143 are changed such that the cabin 120 is tilted forward. A second distance 155a between the cabin mounted distance sensor 151a and the chassis mounted distance sensor 152a is measured in this tilted position P of the cabin 120. In figure 3b, the reference position Pref of the cabin 120 is illustrated with dashed lines, and the displacement D is schematically illustrated for a corner of the cabin 120.

[0117] As schematically illustrated in figures 3a-b, the distance 155a between the cabin mounted distance sensor 151a and the chassis mounted distance sensor 152a is altered / changed by the braking action taking place. This altered second distance 155a between the cabin mounted distance sensor 151a and the chassis mounted distance sensor 152a, i.e. the displacement D of the cabin 120, is utilized by the herein described aspects and embodiments to estimate the motion of the cabin 120 relative to the chassis 110.

[0118] Corresponding distance alternations between essentially any number of cabin mounted distance sensors 151a, 151 b, 151c and chassis mounted distance sensors 152a, 152b, 152c, and / or between one or more load receiving arrangement mounted distance sensors 153a, 153b, 153c and chassis mounted distance sensors 152a, 152b, 152c may be utilized for estimating movements of these vehicle body portions in relation to the chassis 110.

[0119] According to an embodiment, the estimation 230 of the motion of the portion120, 130 further comprises the step of determining 233, for the vehicle 100 in use / movement / motion, an orientation of the at least one distance sensor 151a attached on the portion 120, 130 of the vehicle body. The motion of the portion 120, 130 of the vehicle body in relation to the chassis 110 is then estimated 234 based also on the determined orientation of the at least one distance sensor 151 .

[0120] For example, the motion of the portion 120, 130 may be determined based on a difference between the determined current orientation of the at least one distance sensor 151a and a reference / nominal orientation of the at least one distance sensor 151a, where the difference indicates a displacement of the at least one distance sensor 151a. The reference / nominal orientation of the at least one distance sensor 151a may either be known from mounting of the at least one distance sensor 151a, or may be determined based on earlier measurements utilizing the distance sensors.

[0121] The hereby determined orientation of the at least one distance sensor 151a may be utilized as a basis for a confirmation of the herein described estimation of the motion of the portion 120, 130. Thus, the determination of the orientation provides for improved robustness of the herein described motion estimation, since this is another measurement usable for checking if the displacement determined based on distance measurements by the distance sensors and the displacement determined based on the orientation have corresponding values. The orientation information may in other words be used for checking if the positions of the portion 120, 130 determined based on the distance measurements are within acceptable value ranges.

[0122] The orientation may here be determined 233 based the above mentioned distance measurements between the portion 120, 130 and the chassis 110, if at least three distance sensors 151a, 151 b, 151c, 153a, 153b, 153c on the portion 120, 130 and at least three distance sensors 152a, 152b, 152c on the chassis 110 are utilized for performing these measurements. Thus, at least three pairs of portion and chassis mounted distance sensors are here configured for performing measurements, where each distance sensor is only part of one such pair / measurement.

[0123] The orientation may also be determined 233 based on inertial measurement unit (IMU) information provided by the at least one distance sensor of the portion 151a, 151 b, 151c, 153a, 153b, 153c. According to an embodiment, the distance sensors 151a, 151 b, 151c, 153a, 153b, 153c, 152a, 152b, 152c are ultra wide band sensors with integrated inertial measurement units. Hereby, the on inertial measurement unit information is easily provided.

[0124] Thus, if the one or more distance sensors 151a, 151 b, 151c, 153a, 153b, 153c on the cabin 120 and / or on the load receiving arrangement 130 are configured / designed to also provide inertial measurement unit information, then this information may be utilized for determining the orientation. The inertial measurement unit information may be provided by inertial measurement units comprising arrangements able to measure for example angular velocity, translational accelerations and / or surrounding magnetic fields. Such arrangements may for example comprise gyroscopes, accelerometers and / or magnetometers.

[0125] According to an embodiment, the position of at least one of the one or more distance sensors 151a, 151 b, 151c mounted on the cabin 120 and / or at least one of the one or more distance sensors 153a, 153b, 153c mounted on the load receiving arrangement 130 is determined based on a triangulation utilizing the at least three measured distances. For determining the position of at least one distance sensor mounted on the cabin 120 by triangulation, at least three distance sensors should be mounted on either of the chassis 110 and the cabin 120 and at least one distance sensor should be mounted on the other one of the chassis 110 and the cabin 120. Then, distances between these cabin and chassis mounted distance sensors are measured, respectively. For example, at least three distance sensors 151a, 151 b, 151c may be mounted on the cabin 120 and at least one distance sensor 152a, 152b, 152c may be mounted on the chassis 110 for such measurements. Alternatively, at least three distance sensors 152a, 152b, 152c may be mounted on the chassis 110 and at least one distance sensor 151a, 151 b, 151c may be mounted on the cabin 120 for such measurements. Correspondingly, for determining the position of at least one distance sensor mounted on the load receiving arrangement 130 by triangulation, at least three distance sensors should be mounted and used for measuring on either of the chassis 110 and the load receiving arrangement 130 and at least one distance sensor should be mounted on the other one of the chassis 110 and the load receiving arrangement 130.

[0126] According to an embodiment, the orientation of at least one of the one or more distance sensors 151a, 151b, 151c mounted on the cabin 120 and / or at least one of the one or more distance sensors 153a, 153b, 153c mounted on the load receiving arrangement 130 may also be determined based on a triangulation. For determining the orientation of at least one distance sensor mounted on the cabin 120 by triangulation, at least three distance sensors should be mounted on each of the chassis 110 and the cabin 120, and corresponding distances between these chassis and cabin mounted distance sensors are measured. Correspondingly, for determining the orientation of at least one distance sensor mounted on the load receiving arrangement 130 by triangulation, at least three distance sensors should be mounted for measuring on each of the chassis 110 and the load receiving arrangement 130.

[0127] More in detail, the initial positions at rest for the one or more distance sensors 151a, 151 b, 151c mounted on the cabin 120, the one or more distance sensors 153a, 153b, 153c mounted on the load receiving arrangement 130, and the one or more distance sensors 152a, 152b, 152c mounted on the chassis are known from installation in the manufacturing / assembly line and / or from known dimensions of the vehicle 100. These initial positions may also be determined based on two or more earlier position determinations, as herein described.

[0128] The positions paof the chassis mounted distance sensors 152a, 152b, 152c are known since they are fixed in relation to the chassis 110. However, the positions pnof the one or more distance sensors 151a, 151 b, 151c mounted on the cabin 120 and / or the one or more distance sensors 153a, 153b, 153c mounted on the load receiving arrangement 130 when the vehicle 100 is in motion may differ from their initial positions for the vehicle 100 at rest. Thus, the positions pnof the one or more cabin mounted distance sensors 151a, 151 b, 151c and / or the one or more load receiving arrangement mounted distance sensors 153a, 153b, 153c may be unknown when the vehicle 100 is in use / motion.

[0129] Updated positions pnfor the one or more cabin mounted distance sensors 151a, 151 b, 151c and / or the one or more load receiving arrangement mounted distance sensors 153a, 153b, 153c may be determined based on an optimization function as:

[0130] Where:

[0131] - paare the known positions of the one or more chassis mounted distance sensors 152a, 152b, 152c;

[0132] - pnare the unknown positions of the one or more cabin mounted distance sensors 151a, 151 b, 151c and / or the one or more load receiving arrangement mounted distance sensors 153a, 153b, 153c; and

[0133] - r£are the measured distances 155a, 155b, 155c between the unknown positions of the one or more cabin mounted distance sensors 151a, 151b, 151c and / or the one or more load receiving arrangement mounted distance sensors 153a, 153b, 153c, and the known positions of the one or more chassis mounted distance sensors 152a, 152b, 152c, respectively.

[0134] As schematically illustrated for the example in figure 3a, the initial position at rest for the cabin mounted distance sensor 151a is known. Since the position paof the chassis mounted distance sensor 152a is also known, the distance between these distance sensors 151a, 152a is known when the cabin 120 is non-moving.

[0135] However, when the vehicle 100 is braked, the cabin 120 is tilted in the forward direction, as illustrated in figure 3b, and the position pnfor the cabin mounted distance sensor 151a then becomes unknown. By measuring the distance r£155a between the cabin mounted distance sensor 151a and the chassis mounted distance sensor 152a, and by utilizing the optimization function of equation 1 above, the unknown position pnfor the cabin mounted distance sensor 151a can be determined in relation to the chassis 110. Hereby, the tilting motion of the cabin 120 illustrated in figure 3b may also be estimated.

[0136] In figures 3a-b, only one cabin mounted distance sensor 151a, one chassis mounted distance sensor 152a and one distance 155a therebetween are illustrated for simplicity. However, the same principle as illustrated in figures 3a-b and described above may be applied for two or more cabin mounted distance sensors, two or more chassis mounted distance sensor and two or more distances. Also, the same principle is also applicable for load receiving arrangement mounted sensors.

[0137] Generally, by measuring one distance r£between the one or more cabin mounted distance sensors 151a, 151 b, 151c and the one or more chassis mounted distance sensors 152a, 152b, 152c, respectively, a motion of the cabin 120 in one direction / dimension may be estimated, as explained above. By measuring two such individual distances r£between the one or more cabin mounted distance sensors 151a, 151 b, 151c and the one or more chassis mounted distance sensors 152a, 152b, 152c, respectively, a motion of the cabin 120 in two directions / dimensions may be estimated, as explained above. Correspondingly, by measuring three such individual distances r£between the one or more cabin mounted distance sensors 151a, 151 b, 151c and the one or more chassis mounted distance sensors 152a, 152b, 152c, respectively, a motion of the cabin 120 in three directions / dimensions may be estimated, as explained above.

[0138] Correspondingly, by measuring one distance r£between the one or more load receiving arrangement mounted distance sensors 153a, 153b, 153c, and the one or more chassis mounted distance sensors 152a, 152b, 152c, respectively, a motion of the load receiving arrangement 130 in one direction / dimension may be estimated. By measuring two such individual distances r£between the one or more load receiving arrangement mounted distance sensors 153a, 153b, 153c and the one or more chassis mounted distance sensors 152a, 152b, 152c, respectively, a motion of the load receiving arrangement 130 in two directions / dimensions may be estimated. By measuring three such individual distances r£between the one or more load receiving arrangement mounted distance sensors 153a, 153b, 153c, and the one or more chassis mounted distance sensors 152a, 152b, 152c, respectively, a motion of the load receiving arrangement 130 in three directions / dimensions may be estimated.

[0139] Figure 4 schematically illustrates a front view of a vehicle 100 according to an embodiment. Three individual distances 155a, 155b, 155c are here measured between one cabin mounted distance sensor 151a and a first 152a, a second 152b and a third 152c chassis mounted distance sensors, respectively. The first chassis mounted distance sensor 152a is in the example attached at a first side of the vehicle 100, the second chassis mounted distance sensor 152b is attached at the front of the vehicle, and the third chassis mounted distance sensor 152c is attached at the second side of the vehicle. By this configuration, it is possible to capture / estimate a movement of the cabin mounted distance sensor 151a in any direction, i.e. in three directions / dimensions, by utilizing the three individual distance measurements 155a, 155b, 155c. Thus, cabin motion in three directions / dimensions may be estimated by this configuration.

[0140] A corresponding estimation of cabin motion in three dimensions may also be estimated by a configuration comprising three cabin mounted distance sensors 151a, 151 b, 151c and one chassis mounted sensor 152a. More distance sensors, i.e. more than three distance sensors mounted on the cabin 120 or the chassis 110, and more than one distance sensor mounted on the other one of the cabin 120 and the chassis 110, may of course be added to provide more measurements, and thus more distance information. More measurements and distance information may result in even better accuracy for the cabin motion estimation. Figure 5 shows a flow chart for a method 400 to be performed by a control arrangement 500 for motion compensation of sensor information.

[0141] In a first step 410, a motion of the portion 120, 130 of the vehicle body relative to the chassis 110 is estimated according to any one of the herein presented aspects and embodiments.

[0142] In a second step 420, sensor information provided by one or more system sensors 161a, 161 b, 161c, 163a, 163b, 163c configured on the portion 120, 130 of the vehicle body is compensated based on the estimated motion the portion 120, 130. Thus, the information, which may comprise images, point clouds and / or other types of information provided for example by the one or more system sensors 161a, 161 b, 161c mounted on the cabin 120, is compensated such that it matches the information provided by the one or more system sensors 162a, 162b, 162c mounted on the chassis 110. For example, if the vehicle is braked or turned, such that the cabin 120 is tilted in relation to the chassis 110, the images and / or point clouds provided by the one or more system sensors 161a, 161 b, 161c mounted on the cabin 120 are compensated such that they are aligned with corresponding images and / or point clouds provided by the one or more system sensors 162a, 162b, 162c mounted on the chassis 110.

[0143] Figure 6 shows a flow chart for a method 600 performed by a control arrangement 500 for detection of a critical situation.

[0144] In a first step 610, a motion of the portion 120, 130 of the vehicle body relative to the chassis 110 is estimated according to any one of the herein presented aspects and embodiments.

[0145] In a second step 620, a critical situation is detected if the estimated motion exceeds a motion threshold Mth. The solution may for example be used to detect a critical situation when a vehicle rollover could occur. In such situations, the cabin 120 is tilted significantly more than the chassis 110, i.e. the cabin motion exceeds the cabin motion threshold Mth, before this happens. Thus, the method 600 may be used for detecting when the vehicle 100 is approaching the motion limit / threshold for e.g. the vehicle rollover, such that the control system may control the vehicle, or alert the driver, to maneuver such that rollover is avoided.

[0146] Figure 7 shows a flow chart for a method 800 performed by a control arrangement 500 for detection of miscalibration of sensors.

[0147] In a first step 810, a motion of the portion 120, 130 of the vehicle body relative to the chassis 110 is estimated according to any one of the herein presented aspects and embodiments.

[0148] In a second step 820, a miscalibration of one or more system sensors 161a, 161 b, 161c, 163a, 163b, 163c configured on the portion 120, 130 of the vehicle body and one or more system sensors 162a, 162b, 162c configured on the chassis 110 is detected based on the estimated motion.

[0149] When the system sensors 161a, 161 b, 161c, 163a, 163b, 163c are installed / mounted / attached initially, they may be calibrated such that the information they provide is matched / aligned with information from the one or more system sensors 162a, 162b, 162c configured on the chassis 110. However, if e.g. the cabin 120 is tilted, this calibration does no longer hold, and there is a miscalibration between the one or more system sensors 161a, 161 b, 161c, 163a, 163b, 163c and the one or more system sensors 162a, 162b, 162c configured on the chassis 110, which is detected by the method 800.

[0150] According to an embodiment, the second step 820 of miscalibration detection is followed by a step 230 of calibrating the portion mounted system sensors and the chassis mounted system sensors, based on the detected miscalibration. Hereby, the system information provided by the the system sensors 161a, 161 b, 161c, 163a, 163b, 163c configured on the portion is again matched / aligned with the system information provided by the system sensors 162a, 162b, 162c configured on the chassis. The method 800 for miscalibration detection may be combined with the above mentioned method 400 for motion compensation of sensor information, such that the detected miscalibration 800 triggers the compensation 400 of the sensor information.

[0151] According to an aspect, a control arrangement 500 arranged for estimation of motion of a portion 120, 130 of a vehicle body mounted on a chassis 110 of a vehicle 100 is presented. The processing arrangement 500 is configured to measure 210, for the vehicle 100 in use / movement / motion, at least three distances 155a, 155b, 155c between the portion 120, 130 and the chassis 110. The at least three distances 155a, 155b, 155c are measured between at least four distance sensors 151a, 151 b, 151c, 153a, 153b, 153c, 152a, 152b, 152c, wherein one of the portion 120, 130 and the chassis 110 comprises at least three distance sensors 152a, 152b, 152c and the other one of the portion 120, 130 and the chassis 110 comprises at least one distance sensor 151a. The processing arrangement 500 is further configured to determine 220, based on the measured at least three distances 155a, 155b, 155c, a position P of the portion 120, 130 relative to the chassis 110. The processing arrangement 500 is further configured to estimate 230 a motion of the portion 120, 130 of the vehicle body relative to the chassis 110 based on the determined position 120, 130.

[0152] According to various aspects, the control arrangement 500 is configured to perform / execute the above mentioned method 400 for motion compensation of sensor information, the above mentioned method 600 for detection of a critical situation and / or the above mentioned method 800 for detection of miscalibration of sensors.

[0153] According to various embodiments, the control arrangement 500 is configured to perform / execute all of the herein described method embodiments.

[0154] According to an aspect, a vehicle 100 comprising a herein described control arrangement 500 is presented.

[0155] The person skilled in the art will appreciate that a the herein described embodiments for braking a vehicle may also be implemented in a computer program, which, when it is executed in a computer, instructs the computer to execute the method. The computer program is usually constituted by a computer program product 503 stored on a non-transitory / non-volatile digital storage medium, in which the computer program is incorporated in the computer-readable medium of the computer program product. The computer-readable medium comprises a suitable memory, such as, for example: ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), Flash memory, EEPROM (Electrically Erasable PROM), a hard disk unit, etc.

[0156] Figure 8 shows in schematic representation a control unit 500. The control unit 500 comprises a computing unit 501 , which can be constituted by essentially any suitable type of processor or microcomputer, for example a circuit for digital signal processing (Digital Signal Processor, DSP), or a circuit having a predetermined specific function (Application Specific Integrated Circuit, ASIC). The computing unit 501 is connected to a memory unit 502 arranged in the control unit 500, which memory unit provides the computing unit 501 with, for example, the stored program code and / or the stored data which the computing unit 501 requires to be able to perform computations. The computing unit 501 is also arranged to store partial or final results of computations in the memory unit 502.

[0157] In addition, the control unit 500 is provided with devices 511 , 512, 513, 514 for receiving and transmitting input and output signals. These input and output signals can contain waveforms, impulses, or other attributes which, by the devices 511 , 513 for the reception of input signals, can be detected as information and can be converted into signals which can be processed by the computing unit 501 . These signals are then made available to the computing unit 501 . The devices 512, 514 for the transmission of output signals are arranged to convert signals received from the computing unit 501 in order to create output signals by, for example, modulating the signals, which can be transmitted to other parts of and / or systems in the vehicle.

[0158] Each of the connections to the devices for receiving and transmitting input and output signals can be constituted by one or more of a cable; a data bus, such as a CAN bus (Controller Area Network bus), a MOST bus (Media Orientated Systems Transport bus), or some other bus configuration; an ethernet connection; or by a suitable wireless connection. A person skilled in the art will appreciate that the above-stated computer can be constituted by the computing unit 501 and that the above- stated memory can be constituted by the memory unit 502.

[0159] Control systems in modern vehicles commonly comprise communication bus systems consisting of one or more communication buses for linking a number of electronic control units (ECU's), or controllers, and various components located on the vehicle. Such a control system can comprise a large number of control units and the responsibility for a specific function can be divided amongst more than one control unit. Vehicles of the shown type thus often comprise significantly more control units than are shown in figures 1 , 3a-b, 4 and 8, which is well known to the person skilled in the art within this technical field.

[0160] In a shown embodiment, the present invention may be implemented by the one or more herein mentioned control units or processing arrangements 500. The invention can also, however, be implemented wholly or partially in one or more other control units already present in the vehicle, or in some control unit dedicated to the present invention.

[0161] Here and in this document, control units, control entities or processing arrangements are sometimes described as being arranged for performing the methods and / or steps 210, 220, 230, 231 , 232, 233, 234, 400, 600, 800 according to the invention. This also includes that the units, entities or processing arrangements are designed to and / or configured to perform these method steps.

[0162] One or more control entities 710, 720, 730, 731 , 732, 733, 734, 740, 760, 780 may be arranged for performing the methods and / or steps. Such entities 710, 720, 730,

[0163] 731 , 732, 733, 734, 740, 760, 780 may be arranged as separate entities, or may be logically separated but physically implemented in the same unit, or may be both logically and physically arranged together. These control entities 710, 720, 730, 731 ,

[0164] 732, 733, 734, 740, 760, 780 may for example correspond to groups of instructions, which can be in the form of programming code, that are input into, and are utilized by a processor / computing unit 501 when the entities are active and / or are utilized for performing its method steps, respectively. The present invention is not limited to the above described embodiments. Instead, the present invention relates to, and encompasses all different embodiments being included within the scope of the independent claims.

Claims

CLAIMS1. A method (200) performed by a control arrangement (500) for estimation of motion of a portion (120, 130) of a vehicle body mounted on a chassis (110) of a vehicle (100), the method comprising:- measuring (210), for the vehicle (100) in use, at least three distances (155a, 155b, 155c) between the portion (120, 130) and the chassis (110), the at least three distances (155a, 155b, 155c) being measured between at least four distance sensors (151a, 151 b, 151c, 153a, 153b, 153c, 152a, 152b, 152c), wherein one of the portion (120, 130) and the chassis (110) comprises at least three distance sensors (152a,152b, 152c) and the other one of the portion (120 , 130) and the chassis (110) comprises at least one distance sensor (151a);- determining (220), based on the measured at least three distances (155a, 155b, 155c), a position (P) of the portion (120, 130) relative to the chassis (110); and- estimating (230) a motion of the portion (120, 130) of the vehicle body relative to the chassis (110) based on the determined position (P).

2. The method (200) as claimed in claim 1 , wherein the estimation (230) of the motion of the portion (120, 130) is based also on a reference position (Pref) of the portion (120, 130).

3. The method (200) as claimed in claim 2, wherein the estimation (230) of the motion comprises:- determining (231 ) a displacement (D) of the portion (120 ,130) from the reference position (Pref) to the position (P); and- estimating (232) the motion of the portion (120, 130) relative to the chassis (110) based on the determined displacement (D).

4. The method (200) as claimed in any one of claims 2-3, wherein the reference position (Pref) is determined as one in the group of:- based on known dimensions of the vehicle (100);- the position (P) of the portion (120, 130) determined for the vehicle (100) at rest;and- based on two or more positions (P) determined for the vehicle (100) at rest.

5. The method (200) as claimed in any one of claims 1-4, wherein the estimation (230) of the motion further comprises:- determining (233), for the vehicle (100) in use, an orientation of the at least one distance sensor (151a) of the portion (120, 130); and- estimating (234) the motion of the portion (120, 130) relative to the chassis (110) further based on the determined orientation.

6. The method (200) as claimed in claim 5, wherein the orientation is determined (233) based on one in the group of:- distance measurements between the portion (120, 130) and the chassis (110) measured by at least three distance sensors (151a, 151 b, 151c, 153a, 153b, 153c) of the portion (120, 130) and at least three distance sensors (152a, 152b, 152c) of the chassis (110); and- inertial measurement unit information provided by the at least one distance sensor of the portion (151a, 151b, 151c, 153a, 153b, 153c).

7. The method (200) as claimed in any one of claims 1-6, wherein a triangulation based on the at least three measured distances is utilized for determining one or more in the group of:- the position (P) of the portion (120, 130); and- an orientation of the at least one distance sensor (151 ) of the portion (120, 130).

8. The method (200) as claimed in any one of claims 1-6, wherein the portion (120, 130) of the vehicle body comprises one or more in the group of:- a cabin (120) of the vehicle (100); and- a load receiving arrangement (130) of the vehicle (100).

9. The method (200) as claimed in any one of claims 1-8, wherein the at least one distance sensor (151a, 151b, 151c, 153a, 153b, 153c) of the portion (120, 130) is attached according to one or more in the group of:- on a roof (121) of a cabin (120);- at one or more comers (122) of a cabin (120);- at one or more sensors (161 a, 161 b, 161 c, 163a, 163b, 163c) utilized by an autonomous system (300) of the vehicle (100).

10. The method (200) as claimed in any one of claims 1 -9, wherein the at least four distance sensors (151a, 151 b, 151 c, 153a, 153b, 153c, 152a, 152b, 152c) are ultra wide band sensors.11 . The method (200) as claimed in any one of claims 1 -10, wherein positions (P) of the portion (120, 130) relative to the chassis are repeatedly determined (220) during use of the vehicle (100).

12. A method (400) performed by a control arrangement (500) for motion compensation of sensor information, the method comprising:- estimating (410) the motion of the portion (120, 130) of the vehicle body relative to the chassis (110) according to any one of claims 1 -11 ; and- compensating (420), based on the estimated motion, sensor information provided by one or more system sensors (161 a, 161 b, 161 c, 163a, 163b, 163c) configured on the portion (120, 130) of the vehicle body.

13. A method (600) performed by a control arrangement (500) for detection of a critical situation, the method comprising:- estimating (610) the motion of the portion (120, 130) of the vehicle body relative to the chassis (110) according to any one of claims 1 -11 ; and- detecting (620) a critical situation if the estimated motion exceeds a motion threshold (Mth).

14. A method (800) performed by a control arrangement (500) for detection of miscalibration of system sensors, the method comprising:- estimating (810) the motion of the portion (120, 130) of the vehicle body relative to the chassis (110) according to any one of claims 1 -11 ; and- detecting (820) a miscalibration of one or more system sensors (161 a, 161 b, 161 c, 163a, 163b, 163c) configured on the portion (120, 130) of the vehicle body and oneor more system sensors (162a, 162b, 162c) configured on the chassis (110) based on the estimated motion.

15. A computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method according to any one of claims 1 -14.

16. A computer-readable medium comprising instructions which, when executed by a computer, cause the computer to carry out the method according to any one of claims 1 -14.

17. A control arrangement (500) arranged for estimation of motion of a portion (120, 130) of a vehicle body mounted on a chassis (110) of a vehicle (100), the processing arrangement (500) being configured to:- measure (210), for the vehicle (100) in use, at least three distances (155a, 155b, 155c) between the portion (120, 130) and the chassis (110), the at least three distances (155a, 155b, 155c) being measured between at least four distance sensors (151a, 151 b, 151c, 153a, 153b, 153c, 152a, 152b, 152c), wherein one of the portion (120, 130) and the chassis (110) comprises at least three distance sensors (152a, 152b, 152c) and the other one of the portion (120, 130) and the chassis (110) comprises at least one distance sensor (151a);- determine (220), based on the measured at least three distances (155a, 155b, 155c), a position (P) of the portion (120, 130) relative to the chassis (110); and- estimate (230) a motion of the portion (120, 130) of the vehicle body relative to the chassis (110) based on the determined position (120, 130).

18. A control arrangement (500) arranged for motion compensation of sensor information, wherein the control arrangement (500) is configured to:- estimate (410) the motion of the portion (120, 130) of the vehicle body relative to the chassis (110), as claimed in claim 17; and- compensate (420), based on the estimated motion, sensor information provided by one or more system sensors (161a, 161 b, 161c, 163a, 163b, 163c) configured on the portion (120, 130) of the vehicle body.

19. A control arrangement (500) arranged for detection of a critical situation, wherein the control arrangement (500) is configured to:- estimate (610) the motion of the portion (120, 130) of the vehicle body relative to the chassis (110), as claimed in claim 17; and the control arrangement (500) is further configured to:- detect (620) a critical situation if the estimated motion exceeds a motion threshold (Pth).

20. A control arrangement (500) for detection of miscalibration of sensors, wherein the control arrangement (500) is configured to:- estimate (810) the motion of the portion (120, 130) of the vehicle body relative to the chassis (110), as claimed in claim 17; and- detect (820) a miscalibration of one or more system sensors (161a, 161b, 161 c, 163a, 163b, 163c) configured on the portion (120, 130) of the vehicle body and one or more system sensors (162a, 162b, 162c) configured on the chassis (110) based on the estimated motion.21 . A vehicle (100) comprising a control arrangement (500) as claimed in any one of claims 16-20.

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