DE102024113126B4 - Transport device with a system for generating a control signal that represents a change in the orientation of a velocity vector of a transport device - Google Patents

Abstract

The present invention relates to a transport device with a system for generating a control signal that represents a change in the orientation of a reference system velocity vector of a transport device in a reference system.

Description

The present disclosure relates to a transport device with a system for generating a control signal that represents a change in the orientation of a reference system velocity vector of a transport device in a reference system.

Many transportation systems, such as vehicles, require inertial sensor-based orientation estimation. A clear example of an application that relies on orientation estimation is the control of a vehicle radar used in a driver assistance system. To accurately measure the distance to other vehicles ahead, the radar beam must be adjusted according to the vehicle's suspension compression. For example, if the trunk is loaded, the radar beam will point upwards unless it is corrected downwards to detect a further stretch of road ahead.

In principle, any change in the road gradient leads to a change in the orientation of the vehicle's velocity vector and can therefore be detected by an inertial measurement device. However, determining a change in the orientation of the transport device's velocity vector becomes significantly more complex if the transport device has suspension that suspends its structure relative to the ground. In the example above, the ground is defined by the road surface.

The WO 2017 / 129 199 A1 Disclosing a method for determining the rollover state of a vehicle relative to a road surface is based on a rollover model comprising at least one model parameter. The method includes measuring a first value of a driving condition variable using inertial sensors mounted on the vehicle. It further includes determining a defined rollover angle of the vehicle relative to the road surface based on the first measurement and comparing the at least one model parameter of the rollover model with the determined rollover angle and the first measurement. The rollover model represents a function of the rollover angle based on the at least one model parameter as a function of the first value of the measured driving condition variable. Finally, the method includes determining the rollover state of the vehicle using the rollover model based on the first measurement of the driving condition variable and/or a second measurement of the driving condition variable obtained using the inertial sensors.

Furthermore, the DE 10 2022 132 395 A1 A method for generating a reference value for a lateral velocity for estimating the motion state of a vehicle, comprising at least one inertial measurement unit and sensors for detecting a longitudinal velocity, wherein equations of motion are established using data from the inertial measurement unit and the sensors, to which at least one Kalman filter is applied, wherein an observability index is determined from an observation matrix dependent on the yaw rate measured by the inertial measurement unit, which reflects better observation with increasing value, wherein, at low values of the observability index, the lateral velocity is estimated according to a single-track model of the vehicle within its validity, which is determined by a validity index dependent on the yaw rate, a specific force in the lateral direction determined by the inertial measurement unit, a steering angle and the longitudinal velocity, whereby the measurement covariance of the Kalman filter is adjusted accordingly, wherein, in cases of invalidity, the measurement is discarded and the lateral velocity is predicted by the Kalman filter.

In contrast, there is a need for a system to generate a control signal that represents a change in the orientation of the superstructure reference system velocity vector of a transport device in a superstructure coordinate system, wherein the transport device comprises a superstructure suspended from the ground by a spring.

• - Bestimmen eines Kontaktbezugssystem-Geschwindigkeitsaktualisierungsvektors in dem Kontaktkoordinatensystem aus dem Geschwindigkeitsmesssignal,
• - zumindest Transformieren des Kontaktbezugssystem-Geschwindigkeitsvektors in ein gemeinsames Koordinatensystem zum Erzeugen eines Kontaktbezugssystem-Geschwindigkeitsvektors oder Transformieren des Inertialmesssignals in das gemeinsame Koordinatensystem so dass ein Kontaktbezugssystem-Messsignal erzeugt wird,
  • ◯ wobei das Transformieren eine Einfederung der Federung berücksichtigt,
  • ◯ wobei die Einfederung der Federung zumindest unter Verwendung einer vorbestimmten Federkonstante der Federung oder einer Schätzung der Federkonstante oder unter Verwendung eines Einfederungsmesssignals, das von der Steuerung von einem Einfederungssensor an der Transporteinrichtung empfangen wird, modelliert wird,
  • ◯ Berechnen der Richtung des Aufbaubezugssystem-Geschwindigkeitsvektors des Aufbaus in dem gemeinsamen Bezugssystem aus dem Inertialmesssignal oder aus dem Inertialmesssignal in dem gemeinsamen Bezugssystem,
    • - Aktualisieren der Richtung des Aufbaubezugssystem-Geschwindigkeitsvektors unter Verwendung des Kontaktbezugssystem-Geschwindigkeitsvektors oder des Geschwindigkeitsvektors in dem gemeinsamen Bezugssystem, so dass eine aktualisierte Richtung erzeugt wird, und
    • - Berechnen des Steuersignals mit einem Vergleich zwischen der aktualisierten Richtung und einer Referenzrichtung,

wobei zumindest das Steuersignal, ein aus dem Steuersignal abgeleitetes Fahrbahnsteigungssignal oder ein aus dem Fahrbahnsteigungssignal erzeugtes, verarbeitetes Fahrbahnsteigungssignal zum Steuern des steuerbaren Elements verwendet wird.The foregoing problem is solved according to the present disclosure by a transport device according to the attached independent claim 1. The transport device comprises a superstructure, a plurality of wheels or at least one track, a suspension, a mechanically or electronically controllable element, and a system for generating a control signal representing a change in the orientation of a superstructure reference system velocity vector of the transport device in a superstructure coordinate system, wherein the superstructure coordinate system is fixed to the superstructure of the transport device, wherein the superstructure is suspended by the suspension with respect to a virtual contact line, wherein the suspension couples the plurality of wheels or the track to the superstructure such that the superstructure is a sprung mass, wherein the contact line is defined by two contact points of the transport device, wherein at each contact point contact is established between one of the plurality of wheels or the at least one track and the ground, and wherein a contact coordinate system relative to the contact line The system according to the present disclosure comprises an inertial measurement interface, wherein the inertial measurement interface is configured to receive an inertial measurement signal from an inertial measurement device attached to the setup during operation of the system, and wherein the inertial measurement signal represents three translational accelerations and two angular velocities of the transport device on the setup coordinate system. The system also includes an inertial measuring device, wherein the inertial measuring device is effectively connected to the inertial measurement interface, such that in the operation of the system the inertial measurement interface receives the inertial measurement signal, wherein the inertial measuring device has three translational acceleration sensors, wherein the three translational acceleration sensors measure translational accelerations of the transport device along three translational axes of the vehicle in the operation of the system, and two gyroscopes, wherein the two gyroscopes measure angular velocities of rotational movements of the transport device about two rotational axes in the operation of the system, wherein the inertial measuring device (13) outputs the inertial measurement signal representing the translational accelerations and the angular velocities. Furthermore, the system comprises a speedometer interface, wherein the speedometer interface is configured to receive a speed measurement signal from a speedometer of the transport device during system operation, and wherein the speed measurement signal represents a translational velocity of the transport device in the contact coordinate system. The system also comprises the speedometer, wherein the speedometer is effectively connected to the speedometer interface such that, during system operation, the speedometer interface receives the speed measurement signal, and the speedometer outputs the speed measurement signal representing the translational velocity of the transport device in the contact coordinate system. The system further comprises a controller, wherein the inertial measurement interface is effectively connected to the controller such that, during system operation, the controller receives the inertial measurement signal from the inertial measurement interface, and wherein the speedometer interface is effectively connected to the controller such that, during system operation, the controller receives the speed measurement signal from the speedometer interface, and wherein the controller is configured to perform the following steps:

• - Determining a contact reference system velocity update vector in the contact coordinate system from the velocity measurement signal,
• - at least transforming the contact reference system velocity vector into a common coordinate system to generate a contact reference system velocity vector, or transforming the inertial measurement signal into the common coordinate system so that a contact reference system measurement signal is generated,
  • ◯ where the transformation takes into account a compression of the suspension,
  • ◯ wherein the deflection of the suspension is modeled at least using a predetermined spring constant of the suspension or an estimate of the spring constant or using a deflection measurement signal received by the controller from a deflection sensor on the transport device,
  • ◯ Calculating the direction of the setup reference frame velocity vector of the setup in the common reference frame from the inertial measurement signal or from the inertial measurement signal in the common reference frame,
    • - Updating the direction of the setup reference frame velocity vector using the contact reference frame velocity vector or the velocity vector in the common reference frame, so that an updated direction is generated, and
    • - Calculating the control signal by comparing the updated direction with a reference direction,

wherein at least the control signal, a gradient signal derived from the control signal or a gradient signal generated and processed from the gradient signal is used to control the controllable element.

The system according to claim 1 comprises the inertial measurement interface, the inertial measurement device, the speedometer interface, the speedometer and the control system.

The setup coordinate system is sometimes also called the setup reference system. Similarly, the contact coordinate system is sometimes also called the contact reference system. Finally, the common coordinate system is sometimes also called the common reference system.

As soon as the vehicle's reference frame velocity vector has an upward or downward component in the transport system's coordinate system, any system that requires information about the compression of a suspension must be provided with a control signal that specifies the upward or The downward component is represented and adjusted.

The basic idea of the present disclosure is to provide a system for generating such a control signal, which represents a change in the orientation of the superstructure reference system velocity vector of the transport device in the superstructure coordinate system, in a transport device that has a suspension of its superstructure relative to the ground.

In principle, such a control signal can be generated using an inertial measurement signal from the inertial measurement device, which is input into the system's inertial measurement interface. The controller can then calculate any change in the orientation of the transport device's reference frame velocity vector from the inertial measurement signal output by the inertial measurement device.

However, to avoid velocity drift, the inertial measurement signal output by an inertial measurement device must be updated externally at specific time intervals. Velocity drift is typically caused by the inherent design of the chips used to implement the inertial measurement device. In particular, the drift is caused by the integration of noise in the accelerometer or gyroscope.

According to the present disclosure, the inertial measuring device, from which the inertial measurement signal is received from the inertial measurement interface, must be attached to the structure of the transport device during system operation. In one embodiment, the inertial measuring device moves with the structure of the transport device during system operation. That is, in this embodiment, the inertial measuring device is rigidly connected to the structure. In other embodiments, the inertial measuring device is gimbal-mounted to the structure, which, however, requires additional information about the movement of the gimbal suspension relative to the structure.

According to the present disclosure, the inertial measurement signal must represent three translational accelerations and at least two angular velocities of the transport device in the system coordinate system. In one embodiment of the present disclosure, the inertial measurement signal represents three angular velocities of the transport device. It is assumed that in an embodiment in which the inertial measurement system outputs only two angular velocities, a third angular velocity can be replaced by another measurement signal, e.g., from a steering system of the transport device. In particular, the third angular velocity can be replaced by an axis pointing upwards in the system coordinate system.

According to the present disclosure, the updating of the velocity vector derived from the inertial measurement signal is provided by a speedometer. Typically, each transport device includes a speedometer to determine the speed of the transport device, for example, by measuring the angular velocity of the wheels. This speedometer detects the translational velocity of the transport device at the contact coordinate system and outputs a velocity measurement signal representing the translational velocity. In the present application, velocity denotes the magnitude of the change in the position of the transport device over time and is thus a scalar quantity. The velocity vector, in turn, specifies a direction and magnitude corresponding to the velocity.

Speedometers can be electronic or mechanical. For example, a speedometer can be based on measuring the number of revolutions of a wheel in a given period, if the wheel's radius is known. In one embodiment, the speedometer is an encoder, measures accumulated pulses or absolute phases that are integrated, or is an inertial velocity meter.

However, a velocity vector is required to update the inertial measurement signal. This required velocity vector is determined from the velocity measurement signal and is referred to as the contact reference system update vector. In one embodiment, determining the contact reference system velocity update vector relies on an estimation of the direction based on assumptions about the physical properties of the transport device. In another embodiment, where the speedometer is an inertial measurement sensor, the velocity measurement signal represents the contact reference system velocity update vector.

Due to its positioning and operating principle, the speedometer measures the speed of the transport device in the contact coordinate system, while the inertial measuring device measures the three translational accelerations and the two angular velocities of the transport device in the superstructure coordinate system. In a transport device where the superstructure is suspended relative to the ground, the superstructure coordinate system and the contact The coordinate systems relative to each other and their orientation relative to each other change dynamically. Furthermore, the difference between the orientation of the assembly coordinate system and the orientation of the contact coordinate system relative to each other has a static component that depends on the load of the transport device. In order to perform the update appropriately, it must take place in a common coordinate system, so that, according to the present disclosure, a transformation into a common coordinate system or a common reference system is required.

According to the present revelation, there are three different ways to carry out this transformation or a multitude of transformations.

In a first embodiment, the common coordinate system is identical to the setup coordinate system. In this embodiment, the contact reference system velocity update vector determined from the velocity measurement signal is transformed from the contact coordinate system into the common coordinate system, i.e., the setup coordinate system, so that an update vector is generated in the common reference system. Furthermore, the direction of the setup reference system velocity vector in the setup coordinate system is calculated from the inertial measurement signal, and the direction of the setup reference system velocity vector is updated in the common reference system using the update velocity vector, thus generating the updated direction.

In a second embodiment, the common coordinate system is identical to the contact coordinate system. Since the velocity measurement signal represents the velocity of the transport device in the contact coordinate system, in this embodiment the inertial measurement signal is transformed into the common coordinate system, i.e., the contact reference system, so that the inertial measurement signal is generated in the common reference system. The direction of the velocity vector of the structure in the structure coordinate system is then calculated from the inertial measurement signal of the common reference system. The direction of the velocity vector is updated using the contact reference system velocity update vector, thus generating the updated direction.

In a third embodiment, the common coordinate system is a coordinate system that is neither identical to the setup coordinate system nor to the contact coordinate system. In this embodiment, the common coordinate system is either a local coordinate system (local reference system) or an inertial coordinate system (inertial reference system).

In this embodiment, the contact reference system update vector derived from the velocity measurement signal is transformed from the contact coordinate system into the common coordinate system to generate the update vector for the common reference system. Simultaneously, the inertial measurement signal from the setup coordinate system is transformed into the common coordinate system, thus generating the inertial measurement signal for the common reference system. In this embodiment, the direction of the velocity vector is calculated from the inertial measurement signal of the common reference system within the common coordinate system. The update velocity vector of the common reference system is used to generate the updated direction of the velocity vector.

In any case, the control signal is generated by comparing the updated direction with a reference direction. It is obvious that the reference direction must be specified in the appropriate reference system, namely the common coordinate system.

In an embodiment where the common coordinate system is either identical to the contact coordinate system or differs from both the setup coordinate system and the contact coordinate system, generating the control signal could require a back-transformation of the updated direction into the setup coordinate system or a transformation of the reference direction into the common coordinate system.

• - entweder unter Verwendung einer vorgegebenen Federkonstante der Federung oder unter Verwendung einer Schätzung der Federkonstante modelliert wird,
• - oder aus einem Messsignal für die Einfederung der Federung modelliert wird, das von der Steuerung von einem Sensor für die Einfederung der Federung an der Transporteinrichtung empfangen wird, oder
• - unter Verwendung einer Schätzung der Federkonstante und unter Verwendung eines Messsignals für die Einfederung, das von der Steuerung von einem Einfederungssensor an der Transporteinrichtung empfangen wird, modelliert wird.

In each embodiment according to the present disclosure, the transformation takes into account a deflection of the suspension, wherein the deflection of the suspension

• - is modeled either using a given spring constant of the suspension or using an estimate of the spring constant,
• - or is modeled from a measurement signal for the suspension travel received by the controller from a suspension travel sensor on the transport device, or
• - using an estimate of the spring constant and using a deflection measurement signal provided by the control unit The movement is modeled by a spring-loaded sensor on the transport device.

In one embodiment of the present disclosure, the deflection of the suspension is modeled using a predetermined spring constant of the suspension or an estimate of the spring constant, wherein the modeling of the deflection uses the inertial measurement signal and the velocity measurement signal.

In one embodiment of the present disclosure, the predetermined spring constant is one from a plurality of spring constants stored in a lookup table, wherein the appropriate spring constant is selected from the lookup table depending on a state of the suspended system.

In one embodiment of the present disclosure, the contact line comprises at least one non-zero projection onto a straight-ahead orientation of the transport device. In another embodiment, the contact line runs parallel to the straight-ahead orientation of the transport device. In one embodiment, the two contact points defining the contact line are the contacts between two wheels of the transport device and the ground.

In a further embodiment of the present disclosure, the contact line is part of a definition of a contact plane spanned by three contact points between the transport device and the ground. In one embodiment, these three contact points are the contacts between three wheels of the transport device and the ground.

In one embodiment, the suspension of the transport device is taken into account at least during the transformation of the contact reference system velocity update vector from the contact coordinate system into the common coordinate system to generate the velocity update vector in the common reference system, or during the transformation of the inertial measurement signal into the common coordinate system to generate the inertial measurement signal in the common reference system.

The suspension of a transport device can change due to load (weight) and dynamics (acceleration). Therefore, according to one embodiment of the present disclosure, a dynamic model is used to estimate the expected compression of the suspension due to load and dynamics. In one embodiment, the expected compression of the suspension is expressed as the estimated dynamic pitch δp of the superstructure, which is defined as the angle between the superstructure and the ground. This angle describes the pitching of the superstructure. In one embodiment, δp is defined as $$\delta p=filterstaticalalpha+a_f\times dynamicpitchcoefficient,$$
where filterstaticalalpha is the estimated static component of δp, where a _f is the forward acceleration in the common coordinate system, and where dynamicpitchcoefficient is an empirical constant that describes the dynamic behavior of the suspension.

In one embodiment, determining filterstaticalalpha statistically accounts for the influence of the road gradient. In this embodiment, the model that considers the road gradient is binary. When the transport device is stationary (velocity zero), the road gradient is assumed to remain constant, and filterstaticalalpha is assumed to change instantly according to the inertial measurement signal. As soon as the transport device moves (velocity greater than zero), the road gradient is assumed to change, and filterstaticalalpha is estimated as a slowly varying state. This model is extended in one embodiment to allow for more complex considerations of the road gradient, for example, by taking into account a torque in addition to the velocity of the transport device.

• Aktualisieren des Geschwindigkeitsvektors unter Verwendung des Kontaktbezugssystem-Geschwindigkeitsaktualisierungsvektors oder des Geschwindigkeitsaktualisierungsvektors des gemeinsamen Bezugssystems, so dass ein aktualisierter Geschwindigkeitsvektor erzeugt wird, und
• Berechnen einer Position der Transporteinrichtung unter Verwendung einer Anfangsposition und des aktualisierten Geschwindigkeitsvektors in Abhängigkeit von der Zeit.

In a further embodiment of the present disclosure, the updated velocity vector is used to determine a position of the transport device using an initial position and the updated velocity vector as a function of time. According to one embodiment of the present disclosure, the control is therefore configured to perform the following steps:

• Updating the velocity vector using the contact reference frame velocity update vector or the common reference frame velocity update vector, so that an updated velocity vector is generated, and
• Calculating the position of the transport device using an initial position and the updated velocity vector as a function of time.

In one embodiment, a road gradient signal is used, which indicates a road gradient. The roadway on which the transport device moves is represented, determined from the control signal.

In a further embodiment of the present disclosure, when determining the road gradient signal from the control signal, at least one of the following values is taken into account in addition to the control signal: a measured value for a change in translational speed, a measured value for a wheel torque, and a measured value for a brake pressure. This increases the accuracy of the road gradient signal.

Due to the surface structure of a road, the road gradient signal consists of low-frequency components that describe the general gradient of the road and high-frequency components that describe more detailed changes in the road surface, such as bumps and potholes. Consequently, in one embodiment, the road gradient signal is filtered with a low-pass filter to generate a processed road gradient signal that removes irregularities and potholes in the road surface. This processed control signal makes it possible to compensate for rapidly occurring road surface irregularities.

In one embodiment, the low-pass filter is a signal processing filter such as an infinite pulse filter or a finite pulse filter, where road surface irregularities are considered as high-frequency noise, or it is a stochastic Kalman filter, where road surface irregularities are statistically modeled as noise.

In one embodiment of the present disclosure, the control signal represents not only a change in the orientation of the velocity vector but also a change in the magnitude of the velocity (the speed).

The inertial measurement device comprises three translational acceleration sensors, wherein the three translational acceleration sensors measure translational accelerations of the transport device along three translational axes of the vehicle during system operation, and comprises two gyroscopes, wherein the two gyroscopes measure angular velocities of rotational movements of the transport device about two rotational axes during system operation, wherein the inertial measurement device outputs the inertial measurement signal representing the translational accelerations and angular velocities; and wherein the inertial measurement device is effectively connected to the inertial measurement interface such that, during system operation, the inertial measurement interface receives the inertial measurement signal.

In one embodiment of the present disclosure, the inertial measuring device comprises three gyroscopes, wherein the three gyroscopes measure angular velocities of rotary movements of the transport device about three rotational axes during the operation of the system.

In one embodiment of the present disclosure, instead of measuring a third angular velocity by the inertial measuring device, the third angular velocity is replaced by another measuring signal, e.g., from a steering system of the transport device. In another embodiment of the present disclosure, only an upward or downward gyroscope is replaced by another measuring signal not originating from the inertial measuring device.

In one embodiment of the present disclosure, the translational acceleration sensors and the gyroscopes are distributed over the structure of the transport device.

According to an alternative embodiment of the present disclosure, the inertial measuring device is an inertial measurement unit (IMU). In one embodiment of the present disclosure, the inertial measuring device is an IMU with six degrees of freedom (3 translational accelerometers + 3 gyroscopes).

In one embodiment of the present disclosure, the three translation axes are perpendicular to each other, with each of the rotation axes being identical to one of the translation axes.

The speedometer outputs the speed measurement signal, which represents the translational speed of the transport device on the contact coordinate system; and wherein the speedometer is effectively connected to the speedometer interface, such that the speedometer interface receives the speed measurement signal during the operation of the system.

In one embodiment of the present disclosure, the suspension is spring-based or a pneumatic or hydraulic suspension. In each case, the stiffness of the suspension is described by its spring constant.

The transport device comprises a mechanically or electronically controllable element, wherein at least the control signal, the gradient signal or the processed gradient signal is used to control the controllable element. According to one embodiment of the present disclosure, the controllable element is selected from a group comprising a headlight, a distance radar, and an image cropping means of an image generator, or a combination thereof. Which of the control signal, the gradient signal, or the processed gradient signal is applied to the controllable element depends on which properties of the transport equipment or the road are to be compensated. If compensation for the response of the suspension to a load on the transport equipment or a dynamic response of the suspension to acceleration or deceleration is required, the control signal is to be used. If compensation for the gradient and/or rapidly occurring changes in the road surface, such as bumps and potholes, is required, the gradient signal or the processed gradient signal derived from the control signal is to be used.

In one embodiment of the present disclosure, at least the control signal, the gradient signal or the processed gradient signal can also be used to control the translational speed of the transport device, a torque of a wheel or track chain or a motor of the transport device and/or a brake pressure of the transport device.

• 1 ist eine schematische Seitenansicht einer Transporteinrichtung gemäß der vorliegenden Offenbarung.
• 2 ist eine schematische Darstellung eines Systems gemäß der vorliegenden Offenbarung.
• 3 ist ein schematisches Flussdiagramm der in dem System von 2 erforderlichen Berechnungen.

Further advantages, features, and applications of the present disclosure will become apparent from the following description of embodiments and the corresponding accompanying figures. The foregoing, as well as the subsequent detailed description of the embodiments, will be better understood when read in conjunction with the accompanying drawings. It is understood that the embodiments shown are not limited to the exact arrangements and instruments depicted. In the figures, similar elements are identified by the same reference numerals.

• 1 is a schematic side view of a transport device according to the present disclosure.
• 2 is a schematic representation of a system according to the present disclosure.
• 3 is a schematic flowchart of the system of 2 required calculations.

An exemplary embodiment of the present disclosure is described with reference to the 1 , 2 until 3 described in more detail. For this example, it is assumed that the transport device is a vehicle 1 with four wheels 2, 3 (in the side view of 1 (Only two wheels are visible). The vehicle has a superstructure 4, which is suspended by the vehicle's suspension, comprising two combinations 5 of a spring and a damper at each wheel. Furthermore, the vehicle 1 has a front radar 6 that measures the distance to the nearest vehicle or obstacle on the road 7.

To provide accurate distance readings, a beam 8 of the radar 6 must be approximately parallel to an orientation of the vehicle 1's velocity vector 9. To correctly steer the radar 6's beam 8, 8', the vehicle 1 has a system 11 for generating a control signal 25, which represents any change in the orientation of the velocity vector 9 relative to a reference vector 10 attached to the superstructure 4.

The velocity vector 9 in reference frame 15 is parallel to the velocity vector 23. The velocity vectors are defined by the contact point 20, 21 of wheels 2, 3. The velocity vector 23 is known in a local reference frame (defined by the plumb line 28), and its rapid changes (due to the road undulation 27) can be stochastically filtered or low-pass filtered. δp defines the control signal for correcting the beam 8 to reach its corrected position 8'. The angles defined by vectors 28, 23, and 10 are interdependent. Thus, the low-pass filtered direction of vector 23 affects the control signal based on δp, enabling it to react quickly and compensate for road irregularities.

System 11 is in 2 schematically represented. System 11 comprises an inertial measurement interface 12, which is functionally coupled to a six-degree-of-freedom IMU 13 as an inertial measurement device within the meaning of the present disclosure. During operation of system 11, an inertial measurement interface 12 receives an inertial measurement signal from the IMU 13, representing three translational accelerations and three angular velocities of the vehicle 1. In the embodiment shown, the three translational accelerations are measured along three mutually perpendicular axes. The three angular velocities, in turn, are measured around these axes.

The IMU 13 is part of the vehicle 1 and is attached to the superstructure 4 of the vehicle 1. In this embodiment, the IMU 13 also moves together with the superstructure 4 of the vehicle 1, i.e., it cannot rotate relative to the superstructure 4. Since the IMU 13 is attached to the superstructure 4 and moves with it The inertial measurement signal 14 represents translational accelerations and angular velocities of the vehicle 1 in a reference system 15 (also called the setup coordinate system).

Furthermore, the system 11 also includes a speedometer interface 16. The speedometer interface 16 is effectively connected to the vehicle's speedometer 17, so that during operation the speedometer interface 16 receives a speed measurement signal 18 representing the vehicle's speed at the contact reference system 19 (also referred to as the contact coordinate system).

Both the inertial measurement signal 14 and the velocity measurement signal 18 are input into a controller 24. The controller 24 calculates the control signal 25 from the signals 14 and 18 and outputs the control signal 25 to the radar 6 to steer the radar beam 8, 8'.

Due to its positioning and operating principle, the speedometer 17 measures the speed 3 of the vehicle 1 at the contact reference system 19, while the IMU 13 measures the three translational accelerations and the three angular velocities of the vehicle 1 at the body reference system 15. Since the body 4 is suspended relative to the wheels 2, 3 and thus to the roadway 22 representing the ground, the body reference system 15 and the contact reference system 19 move relative to each other, and their orientation to each other changes dynamically during the movement of the vehicle 1.

The suspension of the wheels 2, 3 results in the structure 4 being suspended with respect to a virtual contact line connecting the contact points 20, 21 of the two wheels 2, 3, with this contact line running parallel to the straight-ahead travel of the vehicle 1.

The correct calculation of the orientation of the vehicle 1's velocity vector 9 requires an update based on the speed measurement signal 18 to avoid drift in the calculated velocity vector. Since the speed measurement signal 18 only represents the magnitude of the velocity, the orientation of the velocity vector in the contact reference frame must first be determined in order to construct the complete velocity vector from this orientation and the measured magnitude of the velocity.

In order for the update to be carried out correctly, it must also take place in a common reference system, which requires a transformation of one of the input signals 14, 18 or both into the common reference system.

For the present example, it is assumed that the common reference frame is identical to the contact reference frame 19. Therefore, before the update is performed, the velocity vector 9 determined from the inertial measurement signal 14 is transformed from the setup reference frame 15 into the contact reference frame 19.

Referring to the schematic flowchart of the 3 The calculation steps performed by the controller 24 to generate the control signal 25 are explained in more detail below.

In general, the coordinate transformation matrix, which transforms vectors from the setup reference system 15 into a local reference system, can be updated as follows for three orthogonally arranged gyroscopes: $${\dot{C}}_b^i=C_b^i{\Omega }_{ib}^b,$$ where ${\dot{C}}_b^i$ the time derivative of the matrix C is denoted and ${\Omega }_{ib}^b$ a skew-symmetric matrix of the following form is $${\Omega }_{ib}^b=\left[\begin{array}{ccc}0& -r& q\\ r& 0& -p\\ -q& p& 0\end{array}\right],$$ where the matrix ${\Omega }_{ib}^b$ formed using information obtained from a gyroscope (scalars p, q, r) with respect to three axes: $${\omega }_{ib}^b={\left[pqr\right]}^T,$$ where T denotes a transpose of a matrix.

The setup reference frame (b) 15 is defined by the sensitive axes of the IMU 13, where i is the inertial frame and ${\Omega }_{ib}^b$ The superscript numbers denote the rotation rate between the setup and the inertial frame, expressed in the setup reference frame 15. The local navigation reference frame is the common reference frame L. Data processing and transformation between the reference frames can be performed by matrix multiplication: $$C_b^L=C_i^L{C}_b^i,$$ where $C_i^L$ The matrix includes the Earth's rotation and the transport rate. The common reference frame L can be defined such that its third axis is aligned with the Earth's gravitational force and points upwards. Depending on the accuracy of the IMU and the available additional information, the matrix can $C_i^L$ can be estimated or ignored. Neglecting the matrix results in increased gyroscope bias errors in the filter.

Three orthogonally mounted accelerometers measure a specific force, a combination of inertial and gravitational acceleration (local gravitational vector g): $$f_{SF}=\dot{v}-g$$

To determine the velocity 9 of the setup 4, the local gravitational force must be calculated and added to the measurement when integrating v̇. Gravity is a function of latitude and altitude, and if these are unknown, the system must estimate or approximate the strength of the gravitational force. However, it can be assumed that the direction of gravity is in the direction of the local vertical (e.g., the direction of the plumb line). The accelerometers can be assumed to be oriented in the setup reference frame 15, like the gyroscopes. The setup reference frame velocity vector 9 is defined as the time derivative of a position vector of the setup reference frame origin. This position vector connects a fixed point on Earth to the moving transport device.

The odometer 17 of vehicle 1 measures the speed at which the wheels are rotating. The speed sensors of the individual wheels can be combined and added to determine the distance traveled. It should be noted that an odometer alone does not provide a directed velocity vector – the wheel radius must be known or estimated to obtain the correct value, and the direction of travel must be deduced from the fact that the wheels are traveling parallel to the road surface 22.

The IMU 13 delivers the inertial measurement signal 14 to the setup reference system 15. It should be noted that the methods known from the prior art provide orientation, velocity and position with respect to the local reference system (where the specific force at rest provides the upward direction 28).

Similar to the methods known in the prior art, the position vector between the inertial sensor unit (IMU) and the wheel must be entered (or estimated from the sensor measurements), see Groves, Principles of GNSS, Inertial, and Multisensor Integrated Systems, 2nd Edition, Chapter 6.3.1. Linear odometry For multisensor integrated navigation, measurements from wheel speed sensors can be integrated, as shown in Groves Chapter 16.2.3 Odometry.

The inertial measurement signal is used to estimate the direction of the velocity vector by integrating the acceleration measurements in the selected reference frame and adding the force of gravity (Grove's Chapter 5.4.3 Velocity Update). Inertial sensors can exhibit significant noise and distortion terms, and unknown transport rate terms, Coriolis terms, and the gravity model can introduce errors into the result. Due to sensor distortions, the inertially calculated velocity contains a significant drift error.

The speed update from the wheel speed sensor 17 is used to correct this drift with an extended Kalman filter. The prediction is performed by combining the inertial measurement signal 14 and statistical models, and the update is performed by updating the speedometer reading with the corresponding statistical error model.

As in ( Rogers, Applied Mathematics in Integrated Navigation Systems, AIAA Education Series, p. 259 As shown in Figure 1, an installation error in a speed sensor leads to a speed error. In connection with this embodiment, the vehicle's suspension causes a similar type of error, but this error is not constant. It can change depending on the vehicle's load or acceleration. The angle at which the body is tilted relative to the ground, and which causes the error, is shown in Figure 1. 1 represented as δp. δp is also referred to as the estimated dynamic pitch of the structure.

Now, the construction of a measurement vector for a Kalman filter is explained (Groves 3.2.4). The static component of δp is called staticalpha. An estimated state is represented by adding filter to the name. In particular, filterstaticalpha is the static component estimated by the filter.

• - δp das geschätzte dynamische Nicken des Aufbaus ist, bestimmt aus einer statischen Komponente und einer dynamischen Komponente proportional zur Längsbeschleunigung,
• - v_odo die gemessene Radgeschwindigkeit aus dem Geschwindigkeitsmesser ist,
• - s der geschätzte Kilometerzähler-Skalierungsfaktor ist (der die Unsicherheit des Reifenumfangs aufgrund von Luftdruck, Laufflächenabnutzung usw. repräsentiert),
• - v^B die geschätzte Geschwindigkeit ist, ausgedrückt im Aufbaubezugssystem 15, und
• - δL die Hebelarmkorrektur zur Übertragung der Geschwindigkeitsmessung vom Reifenkontaktpunkt zum Ort der IMU ist.

There is, of course, an uncertainty in the correction, but this is taken into account by the filter. The link to states, a measured model in the Kalman filter, can be, for example, $$\delta p=filterstaticalpha+a_f\times dynamicpitchcoefficient$$ $$\left[\begin{array}{c}{v}_{odo}\\ 0\\ 0\end{array}\right]=s\left[\begin{array}{ccc}1& 0& \delta p\\ 0& 1& 0\\ -\delta p& 0& 1\end{array}\right]\left(v^B+\delta L\right)$$ Where:

• - δp, the estimated dynamic pitch of the structure, is determined from a static component and a dynamic component proportional to the longitudinal acceleration.
• - v _odo the measured wheel speed from the speedometer is,
• - s is the estimated odometer scaling factor (which represents the uncertainty of the tire circumference due to air pressure, tread wear, etc.),
• - v ^B is the estimated velocity, expressed in the frame of reference 15, and
• - δL is the lever arm correction for transferring the speed measurement from the tire contact point to the location of the IMU.

A stochastic model for the dynamic alpha allows the road gradient to also be modeled stochastically – the road gradient can only change when the vehicle is in motion. The knowledge that the vehicle is stationary can be obtained, for example, from the odometer, the brakes, or the ignition switch position. Applying this information in a filter can be done with an additional restriction in the filtering process; for example, if the vehicle is switched off, the road gradient is stored in memory. When the vehicle is switched on again, this information is used to initialize the filter. Any change in δp is then observed as a change in the suspension.

The signal derived from δp can be further adjusted by low-pass filtering of the road gradient to remove the influence of bumps and potholes in the control signal.

In accordance with the original disclosure, it is pointed out that all features as they can be deduced by a person skilled in the art from the present description, the drawings, and the claims, even if they are expressly described only in conjunction with certain other features, can be combined individually or in any combination with other features or groups of features disclosed herein, unless this is expressly excluded or technical circumstances render such combinations impossible or pointless. A comprehensive, explicit description of all conceivable combinations of features is omitted here solely for the sake of brevity and readability.

Although the invention is illustrated and described in detail in the drawings and the preceding description, this illustration and description are merely exemplary and are not intended to limit the scope of the claims. The invention is not limited to the embodiments shown.

Variations of the disclosed embodiments will be apparent to a person skilled in the art from the drawings, the description, and the accompanying claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "one" or "a" does not exclude a plurality. The mere fact that certain features are claimed in different claims does not preclude their combination. Reference numerals in the claims are not intended to limit the scope of protection.

Reference symbol list

1

vehicle

2

wheel

3

wheel

4

Construction

5

Spring and damper

6

Front radar

7

roadway

8.8'

beam

9

velocity vector

10

Reference vector

11

system

12

Inertial measurement interface

13

IMU

14

Inertial measurement signal

15

Construction reference system

16

Speedometer interface

17

Vehicle speedometer

18

Speed measurement signal

19

Contact reference system

20, 21

Contact point

22

Road surface

23

Speed in the contact reference system

24

steering

25

control signal

26

Contact line

27

Road surface irregularity

28

Gravity vector

δp

estimated dynamic nodding of the structure

Claims (10)

Transport device (1) comprising a superstructure (4), a plurality of wheels (2, 3) or at least one track, a suspension (5), a mechanically or electronically controllable element, and a system (11) for generating a control signal (25) representing a change in the orientation of a velocity vector (9) of the transport device (1) in a superstructure coordinate system (15), wherein the superstructure coordinate system (15) is attached to the superstructure (4) of the transport device (1), wherein the superstructure (4) is suspended from the suspension (5) with respect to a virtual line of contact (26), wherein the suspension (5) couples the plurality of wheels (2, 3) or the track to the superstructure (4) such that the superstructure (4) is a sprung mass, wherein the line of contact (26) is defined by two contact points (20, 21) of the transport device (1), wherein at each contact point (20, 21) there is contact between a component of the transport device (1) and the component of the suspension (5). a plurality of wheels (2, 3) or the at least one crawler track and the ground (22) is manufactured, and wherein a contact coordinate system (19) is defined with respect to the contact line (26); wherein the system (11) comprises an inertial measurement interface (12), wherein the inertial measurement interface (12) is configured to receive an inertial measurement signal (14) from an inertial measurement device (13) attached to the structure (4) during operation of the system (11), and wherein the inertial measurement signal (14) represents three translational accelerations and two angular velocities of the transport device (1) in the structure coordinate system (15); the inertial measuring device (13), wherein the inertial measuring device (13) is effectively connected to the inertial measurement interface such that, during operation of the system (11), the inertial measurement interface receives the inertial measurement signal, wherein the inertial measuring device (13) comprises three translational acceleration sensors, wherein the three translational acceleration sensors measure translational accelerations of the transport device along three translational axes of the vehicle during operation of the system, and two gyroscopes, wherein the two gyroscopes measure angular velocities of rotational movements of the transport device about two rotational axes during operation of the system, wherein the inertial measuring device (13) outputs the inertial measurement signal representing the translational accelerations and the angular velocities; a speedometer interface (16), wherein the speedometer interface (16) is arranged to receive a speed measurement signal (18) from a speedometer (17) of the transport device (1) during operation of the system (11) to receive, and wherein the speed measurement signal (14) represents a translational velocity of the transport device (1) on the contact coordinate system (19); the speedometer (17), wherein the speedometer (17) is effectively connected to the speedometer interface (16) such that in the operation of the system (1) the speedometer interface (16) receives the speed measurement signal (18), wherein the speedometer (17) outputs the speed measurement signal which represents the translational velocity of the transport device in the contact coordinate system; and a controller (24), wherein the inertial measurement interface (12) is effectively connected to the controller (24) such that the controller (24) receives the inertial measurement signal (14) from the inertial measurement interface (12) during the operation of the system (1), wherein the speedometer interface (16) is effectively connected to the controller (24) such that the controller (24) receives the speed measurement signal (18) from the speedometer interface (16) during the operation of the system (1), and wherein the controller (24) is configured to perform the following steps: determining a contact reference system update velocity vector in the contact coordinate system (19) from the speed measurement signal (18), at least transforming the contact reference system update velocity vector from the contact coordinate system (19) into a common coordinate system such that an update velocity vector is generated in a common reference system, or transforming the inertial measurement signal (14) into the common coordinate system, such that an inertial measurement signal is generated in the common reference system, wherein the transformation takes into account a deflection of the spring (5), wherein the deflection of the spring (5) is modeled, at least using a predetermined spring con The system calculates the direction of the velocity vector in the common coordinate system from the inertial measurement signal (14) or from the inertial measurement signal in the common reference system, updates the direction of the velocity vector using the contact reference system update velocity vector or the update velocity vector in the common reference system, generating an updated direction, and calculates the control signal (25) by comparing the updated direction with a reference direction (10), wherein at least the control signal (25), a road gradient signal derived from the control signal (25), or a processed road gradient signal generated from the road gradient signal is used to control the controllable element. Transport device (1) according to the preceding claim, wherein the deflection of the suspension is modeled using a predetermined spring constant of the suspension or an estimate of the spring constant, wherein the modeling of the deflection uses the inertial measurement signal and the velocity measurement signal. Transport device (1) according to one of the preceding claims, wherein the common coordinate system differs from the setup coordinate system and the contact coordinate system, wherein the contact reference system velocity is transformed from the contact coordinate system into the common coordinate system, so that the velocity is generated in the common reference system, and wherein the inertial measurement signal is transformed from the setup coordinate system into the contact coordinate system, so that the inertial measurement signal is generated in the common reference system. Transport device (1) according to one of the preceding claims, wherein at least the transformation of the contact coordinate system (19) into the common coordinate system to generate the update rate vector in the common reference system or the transformation of the inertial measurement signal (14) into the common coordinate system to generate the inertial measurement signal in the common reference system takes into account an expected compression of the suspension, expressed as an estimated dynamic pitch δp of the structure, wherein preferably $$\delta p=filterstaticalalpha+a_f\times dynamicpitchcoefficient,$$ where δp is an angle between the structure and the ground, where filterstaticalalpha is the estimated static component of δp, where a _f is the forward acceleration in the common coordinate system, and where dynamicpitchcoefficient is an empirical constant that describes the dynamic behavior of the suspension. Transport device (1) according to one of the preceding claims, wherein a road gradient signal is determined from the control signal (25) which represents a road gradient of a roadway on which the transport device (1) moves. Transport device (1) according to the preceding claim, wherein the determination of the road gradient signal from the control signal (25) takes into account, in addition to the control signal (25), at least one measured value for a change in translational speed, a measured value for a torque of a wheel and a measured value for a brake pressure. Transport device (1) to Claim 5 or 6 , wherein the road gradient signal is filtered with a low-pass filter to produce a processed road gradient signal in which bumps and potholes in the road surface have been removed. Transport device (1) according to one of the preceding claims, wherein the control is configured to perform the steps of updating the velocity vector using the contact reference system velocity vector or the velocity vector in the common reference system, so that an updated velocity vector is generated, and calculating a position of the transport device (1) using an initial position and the updated velocity vector as a function of time. Transport device (1) according to the preceding claim, wherein the three translation axes are perpendicular to each other, and wherein each of the rotation axes is identical to one of the translation axes. Transport device (1) according to one of the preceding claims, wherein the controllable element is selected from a group comprising a headlight, a distance radar (6) and an image includes the cropping tool of an image generator or a combination thereof.