ARRANGEMENT AND METHOD FOR DETERMINING A SLOPE SIGNAL IN A VEHICLE

Description

[0001] The present invention relates to an arrangement for determining a gradient signal in a vehicle according to the preamble of patent claim 1, as well as a corresponding method.

[0002] Various methods for measuring inclinations are known in a wide variety of industrial sectors. Sensor devices and structures for determining angles using a measurement and the use of markers and / or reflectors on the object to be measured are known, for example, from European patent EP 2 910 512 B1, as well as US patent application US 2011 / 260 033 A and US patent application US 2016 / 128 783 A. Angle determination using a laser scanner is known, for example, from US patent application US 2016 / 076 228 A. Furthermore, the determination of objects in the path of a vehicle is known from US 2015 / 336546 A1 and US 2010 / 030473 A1. The determination of the width of a roadway is known from US 2015 / 120244 A1. Furthermore, angles can be determined by two measurements with a laser distance meter. US 5 714 928 A shows a collision avoidance system for vehicles.The system includes a first preview sensor that detects an obstacle in front of the vehicle in a first distal detection zone to generate a first signal indicative of the presence of the obstacle and the distance between the obstacle and the front end of the vehicle, and a second preview sensor that detects the obstacle in front of the vehicle in a second proximal detection zone to generate a second signal indicative of at least the presence of the obstacle. The system also includes a third vehicle speed sensor that detects the traveling speed of the vehicle and generates a signal indicative of the vehicle speed.

[0003] Such digital or analog inclinometers determine the angle only at the sensor's position or through multiple measurements of the gradients of a traveled distance, a linear laser scan and subsequent evaluation, or through reflectors on fixed objects. Optical methods, such as image analysis, are also known for this purpose.

[0004] Fixed markers cannot be used to determine inclination in moving reference systems because the terrain to be measured is unknown. In addition, a time-delayed measurement must be taken. According to the known state of the art, for moving reference systems subject to displacement, such as those used in vehicles, only a very complex method is known to date from German patent application DE 10 2007 037 162A1, in which measurement information is recorded that contains at least the measurement points scanned with the laser scanner and the position of the laser scanner associated with the respective measurement points, in relation to trigger times specified by the laser scanner, as well as times specified in a time standard.

[0005] However, no method is currently known that allows the slope angle of the terrain in the preview area of ​​a vehicle, i.e., in a moving reference system, to be determined dynamically in a simple manner and without the use of a laser scanner. A laser scanner is used to scan an object's surface three-dimensionally using a laser beam at a defined angular grid. This allows object surfaces to be scanned, i.e., sampled, with a high point density.

[0006] Therefore, it is an object of this invention to provide an arrangement and a method that enable such determination without a laser scanner. This object is achieved according to the invention by the features of the independent patent claims. Advantageous embodiments are the subject of the dependent claims.

[0007] An arrangement for determining a gradient signal in a vehicle is proposed, as specified in claim 1.

[0008] The proposed arrangement allows for a simple, cost-effective and dynamic determination of inclination data in a moving reference system without the use of a laser scanner.

[0009] In one embodiment, the first laser distance sensor emits two laser beams spread in the vehicle longitudinal axis and vehicle transverse direction at least at the first and second times such that one of the spread laser beams is the first laser beam and is emitted in the direction of the first measuring point, and the second of the spread laser beams is emitted in the direction of a further measuring point remote from the first measuring point.

[0010] In In one embodiment, the two laser beams are emitted by sequential switching, comprising rotating the laser distance sensor or switching the optics of the laser distance sensor.

[0011] In one embodiment, the arrangement comprises a second laser distance sensor arranged on a front side of the vehicle at an angle inclined to the vehicle's longitudinal axis at a predetermined angle, which is configured to direct at least one second laser beam onto a second measuring point in front of the vehicle at least at the first and second times, wherein the at least one means is further configured to determine the length of the laser beam of both laser distance sensors and at least one associated vector of the laser beams in each case, and wherein the at least one determination device is further configured to determine a difference vector from the movement vector and the determined vectors of the laser beams and to form the gradient signal therefrom.

[0012] Using more than one laser beam or even more than one laser distance sensor achieves greater measurement accuracy.

[0013] In one embodiment, the first and second laser distance sensors are arranged next to each other in the transverse direction of the vehicle. This arrangement also allows for the detection of a transverse inclination of the road surface.

[0014] In one embodiment, the arrangement further comprises a further processing device which is configured to further process the gradient signal, wherein the further processing is carried out by sending the gradient signal to a control device present in the vehicle which is configured to further process the gradient signal and to carry out an adaptation of the dynamic parameters based on the received and processed gradient signal. InIn an alternative embodiment, the arrangement further comprises a further processing device which is configured to further process the gradient signal, wherein the further processing is carried out by sending the gradient signal to an external processing device which is configured to further process the gradient signal into control signals and to send them back to the further processing device in the vehicle for carrying out the adaptation of the dynamic parameters of the vehicle.

[0015] By further processing and / or making the results available, both the ego vehicle and other vehicles can benefit from the information, i.e. the determined gradient signal. The data and results can be used for further processing to optimize vehicle parameters for the gradient, either via an internal or external device. Benefiting also means that information can be exchanged between vehicles as raw data for further processing, so that a predictive strategy can be planned. Data can also be exchanged as already processed data that specifies the setting of dynamic parameters. This enables fast and predictive adaptation to the gradient of the terrain. Vehicles that cannot perform their own calculations can also benefit from this information. This way, wear and tear, for example, can beof brakes can be reduced and fuel can be saved.

[0016] Furthermore, a method for determining a gradient signal in a vehicle is provided as set out in claim 7.

[0017] In one embodiment, the determined gradient signal is further processed in a third step.

[0018] In one embodiment, the further processing is carried out by internally calculating a control signal for adapting the dynamic parameters of the vehicle and carrying out the adaptation, or by sending the gradient signal for external processing and receiving at least one control signal determined from the gradient signal for adapting the dynamic parameters of the vehicle and carrying out the adaptation.

[0019] In one embodiment, the further processed gradient signal and / or the control signal are used to digitize the terrain and / or are provided to other vehicles.

[0020] Further features and advantages of the invention will become apparent from the following description of embodiments of the invention, with reference to the figures of the drawing, which show details according to the invention, and from the claims.

[0021] Preferred embodiments of the invention are explained in more detail below with reference to the accompanying drawings. Fig. 1 shows a representation of a stationary calculation of the gradient of a terrain according to the state of the art. Fig. 2 shows a representation of a vehicle for laser distance measurement to determine a road gradient in the preview area at two different times according to an embodiment of the present invention. Fig. 3 shows a top view of a vehicle after Figure 1 according to an embodiment of the present invention. Fig. 4 shows a flowchart of the method according to an embodiment of the present invention.

[0022] In the following descriptions of the figures, the same elements or functions are provided with the same reference symbols.

[0023] The indices 0 and 1 used in the figures indicate the time t=0 and t=1, respectively, at which the respective parameters, e.g. La, Lb, Pa, Pb, Ga or φ determined or measured.

[0024] Figure 1 represents the stationary calculation of the gradient or inclination of a terrain according to the prior art. This calculation will be explained in more detail in the description of the invention, since it serves as the basis for determining the gradient of the present invention.

[0025] Referring to Figures 2 and 3The following describes both the structure of the system and the method for determining the inclination according to one embodiment, in this case the determination of the inclination of a terrain for a vehicle. Based on this determination, various parameters, especially those relating to longitudinal, vertical, and lateral dynamics, can be optimized through further processing.

[0026] A moving reference system is a reference system that is not an inertial system, i.e. it is subject to, among other things, accelerations or movements and displacements.

[0027] The arrangement for determining a terrain or road gradient in a preview area of ​​a vehicle (moving reference system) consists of at least one point-measuring laser distance sensor 2 and an inclinometer 1, which can be designed as an angle sensor, preferably as a digital angle sensor. These are arranged in or on the vehicle, with the angle sensor measuring the angle φ of the vehicle, more precisely its longitudinal axis, relative to a geostationary, i.e. earth-fixed, inertial or absolute system. In Figure 1 and Figure 2 , upper figure, this angle is φ 0, meaning that this is the angle φ at time t 0. In Figure 2 , lower figure, this angle is φ 1, meaning that this is the angle φ at time t 1.

[0028] The laser distance sensor 2 is in a geometrically known position, which is determined from the Figure 2 , upper figure, and Figure 3marked parameters L1, h1 and b1. L1 is the distance (in X-direction) between the inclinometer or angle sensor 1 and the laser distance sensor 2, h1 is the height (in Z-direction) between the vehicle's longitudinal axis X at the height of the laser distance sensor 2 and the terrain, whereby the straight line of height h1 forms a 90° angle with the vehicle's longitudinal axis, i.e., is perpendicular to it. b1 is the distance of the laser distance sensor 2 (in Y-direction) to the vehicle's longitudinal axis (X-direction) or, as in Figure 3 shown, the distance of the laser distance sensor 2 (in the Y direction) to an optional second laser distance sensor 2b is designated. The laser distance sensor 2 should preferably be arranged at the front of the vehicle with a clear field of view into the preview area of ​​the vehicle and be inclined by an angle of inclination α relative to the vehicle's longitudinal axis X in the direction of the roadway or terrain, as shown in Figures 1 and 2 shown.

[0029] As in Figure 1As shown, the gradient or the angle ξ or Ψ of the straight line Ga approximating the terrain with respect to the vehicle-fixed reference system X, Y, Z can be determined from the geometrically known position L1, h1, b1, α of the laser distance sensor 2 in the vehicle and the measured length La 0 of the beam of the laser distance sensor 2 between the laser distance sensor 2 (i.e. the origin of the beam) and a measuring point Pa on the terrain (here at the time t = 0). By converting with the angle signal of the inclinometer 1, the gradient angle in the absolute system is calculated, for example using a method from the prior art, for example according to the method proposed in US 2015 / 355 328 A. Gravity can be used as the measuring principle of the inclinometer 1 to determine the angle with respect to the absolute system, e.g. an acceleration sensor cluster which calculates the angle from the deviation orthe influence of the acceleration due to gravity determines the angular deviation, or a gyroscope or another known principle such as a spirit level, etc., can be used.

[0030] The angle ξ indicates the absolute inclination and can be calculated from the angle φ of the vehicle, more precisely its longitudinal axis, relative to a geostationary, i.e. earth-fixed, inertial or absolute system, as well as the inclination angle α relative to the vehicle’s longitudinal axis X and the Figure 1 The angle δ, i.e. the angle between the straight line Ga and the laser beam La, can be determined. The angle Ψ indicates the relative inclination and can be calculated from the difference between the angle of inclination α relative to the vehicle's longitudinal axis X and the Figure 1 The angle δ, i.e. the angle between the straight line Ga and the laser beam La, can be determined.

[0031] Out of Figure 1 It can be seen that the absolute slope can be calculated as follows: ξ = φ + α − δ

[0032] Out of Figure 1 It can also be seen that the relative inclination can be calculated as follows: Ψ = α − δ where from trigonometry, ie from the triangles formed in each case to determine the angle, the following applies: h 1 / sin δ = ha / sin 90 ° − α , where Ga = h 1 2 + La 2 − 2 ∗ h 1 ∗ La ∗ cos 90 ° − α

[0033] The method according to the invention now provides a dynamic calculation between two discrete time steps, e.g. t=0 and t=1.

[0034] In a first step S1, the position of the vehicle in the absolute system or the distance traveled L by the vehicle is determined, and from this, the corresponding motion vector Ga 0 , Ga 1 is determined at each of the times t=0 and t=1. Ga 0 , Ga 1 is a straight line approximating the terrain, as previously described. This determination can be performed using GPS, an inclinometer 1, or other methods.

[0035] When determining the position using GPS, the inclinometer 1 can be omitted, since the coordinates X, Y, and Z in the absolute system for the times t = 0 and t = 1 are known from the GPS position, and the distance L traveled by the vehicle can be determined vectorially, i.e., a motion vector is determined. This also determines the gradient traveled and, with sufficiently small time steps, the current gradient, which means that the inclinometer 1 can be omitted for areas or applications with good GPS signal coverage.

[0036] Alternatively, the distance L or the motion vector can also be determined from the driving speed or known or recorded wheel or output speeds, whereby the vectorial orientation in the vehicle XZ plane is known from an existing inclinometer 1.

[0037] In a second step S2, the difference vector Ga 0,1 is determined from the now known motion vector Ga 0 , Ga 1 and the vectors of the laser beam, i.e. length La and angle α, at the times t=0 and t=1. This approximates the slope of the terrain much better than the vector Ga for small time steps, as shown in Figure 2 , shown in the figure below.

[0038] In an alternative embodiment, a second laser distance sensor 2b is provided which is inclined by an angle α-β with respect to the vehicle's longitudinal axis X in the direction of the roadway or terrain. The beams La and Lb of the two laser distance sensors 2 and 2b enclose the angle β. Due to the different angles of inclination of the two laser distance sensors 2 and 2b, the measuring points Pa and Pb on the terrain, which are struck by the respective laser beam La or Lb, are spaced from one another. Thus, the two vectors, i.e. length and angle, of the laser beams La and Lb are known at any time and the difference vector Ga 0,1 , i.e. the gradient of the terrain, can be calculated at any time step t = 0, t = 1 etc. and even when stationary.

[0039] Advantageously, the two laser distance sensors 2 and 2b are arranged side by side at the front of the vehicle and with a clear view into the preview area. Advantageously, the terrain vector Gb 0 runs diagonally across the roadway in the preview area, as shown in Figure 3 shown, because in this way, the gradients along and across the direction of travel can be determined from the vector components. To detect the transverse inclination, the two laser distance sensors 2 and 2b are advantageously positioned across the width of the vehicle, i.e., in the Y direction. The inclinometer 1 or the corresponding device for detecting the absolute position of the vehicle, as described above, is the same for both.

[0040] If a single laser distance sensor 2 is used, it is advantageously arranged centrally at the front of the vehicle; a paired arrangement of two laser distance sensors 2 and 2b is advantageously designed symmetrically.

[0041] A measurement of the road's transverse inclination can also be performed by a single, centrally located laser distance sensor 2, which emits two measuring beams, referred to as sensor-internal duplication. These are aligned splayed in the XY plane of the vehicle, i.e., they are at an angle to the vehicle's longitudinal axis X, as shown in Figure 3 as the angle between the arrows to the measuring points Pa and Pb.

[0042] Instead of duplicating the laser distance sensor, sequential switching is also possible. Switching can be accomplished by rotating the sensor or switching the optics, such as the prism. Switching can be done across the lane width or include different preview lengths depending on the driving speed.

[0043] Advantageously, the laser distance sensor(s) are located in the vehicle interior behind the windshield, in an area that is cleaned by the windshield wiper. Integration into the headlight is also particularly suitable, especially if the headlights are plastic. By connecting them to the adjustment device for the cornering lights and level control, correct alignment can be ensured even with changing loads, allowing the preview area to be focused on the relevant area when cornering.

[0044] Advantageously, the laser light has a wavelength in the non-visible range, i.e. in the infrared range IR or in the ultraviolet range UV.

[0045] In a further step S3, the determined gradient signal or the determined inclination data can be further used or processed.

[0046] For example, the vehicle parameters, particularly the dynamic parameters, can now be adjusted based on the determined incline data or the determined gradient signal. The gradient determined in this way can then be used to control longitudinal dynamics, e.g., engine management, shift strategy, traction management, energy management, etc. For example, the transmission downshifts in good time before the incline, all-wheel drive and differential locks are engaged and disengaged in good time, wear-free brakes (retarders) are optimally controlled when driving downhill, and the slip control during start-off (ASR) and braking (ABS) is optimized. With regard to a vehicle's vertical dynamics (heaving, pitching, rolling) and lateral dynamics, the current and predictive gradient signal can be used for improved control.

[0047] Furthermore, there is the option of digitizing the terrain and remotely transmitting the acquired data. Advantageously, the data from multiple vehicles is stored centrally on a server, e.g., in a cloud environment, and compared with map data. Furthermore, driving dynamics settings for longitudinal, vertical, and lateral dynamics can be optimized online or offline and provided to the vehicle or other vehicles, if they have appropriate communication capabilities, in a timely manner or in advance, so that the optimal parameters are already set when the vehicle enters the preview area.

[0048] The advantage of using laser distance sensors is that they are approximately 5-10 times cheaper than laser scanners, very compact, robust, and available with sufficient accuracy. The proposed method and corresponding arrangement make it possible to utilize these advantages and, in addition, provide a system and method that is highly accurate.

Claims

1. Arrangement for determining a gradient signal in a vehicle, having - at least one position detection device (1) which is configured to determine the position of the vehicle in an absolute system (XYZ) at least at a first point in time (t=0) and at a second point in time (t=1), and to use this to determine the distance (L) covered by the vehicle as a movement vector (Ga0, Ga1), and - at least one first laser distance sensor (2) which is arranged with an inclination of a predefined angle (α) with respect to the vehicle longitudinal axis (X) on a front side of the vehicle and whose geometric position (L1, h1, b1, α) in the vehicle is known and which is configured to emit at least one first laser beam at least at the first and the second point in time (t=0; t=1) in the direction of a first measurement point (Pa) in front of the vehicle, - wherein the position detection device is configured to determine the distance (L) covered by the vehicle as a movement vector (Ga0, Ga1) from the position of the vehicle and on the basis of the geometrically known position (L1, h1, b1, α) of the first laser distance sensor (2), and - at least one means which is configured to determine the length of the at least one laser beam (La) and at least one associated vector of the laser beam at each of the at least first and second points in time (t=0; t=1), and - at least one determination device which is configured to determine a differential vector (Ga0,1) from the movement vector (Ga0, Ga1) determined at each of the first and second points in time and each of the determined vectors of the laser beam and to form a gradient signal therefrom.

2. Arrangement according to Claim 1, wherein the first laser distance sensor (2) emits, at least at the first and the second point in time (t=0; t=1), two laser beams spread in the vehicle longitudinal axis (X) and the vehicle transverse direction (Y) in such a way that one of the spread laser beams is the first laser beam and is emitted in the direction of the first measurement point (Pa), and the second of the spread laser beams is emitted in the direction of a further measurement point (Pb) remote from the first measurement point.

3. Arrangement according to Claim 2, wherein the two laser beams are emitted by sequential switching, comprising a rotation of the laser distance sensor (2) or a switching of the optical unit of the laser distance sensor (2).

4. Arrangement according to one of the preceding claims, having a second laser distance sensor (2b) which is arranged with an inclination of a predefined angle (α-β) with respect to the vehicle longitudinal axis (X) on a front side of the vehicle and is configured to direct at least one second laser beam onto a second measurement point (Pb) in front of the vehicle at least at the first and the second point in time (t=0; t=1), wherein the at least one means is furthermore configured to determine the length of the laser beam (La; Lb) from both laser distance sensors (2; 2b) and in each case at least one associated vector of the laser beams, and - wherein the at least one determination device is furthermore configured to determine a differential vector (Ga0,1, Gb0) from the movement vector (Ga0, Ga1) and the determined vectors of the laser beams and to form the gradient signal therefrom.

5. Arrangement according to Claim 4, wherein the first and the second laser distance sensor (2; 2b) are arranged next to one another in the vehicle transverse direction (Y).

6. Arrangement according to one of the preceding claims, wherein the arrangement further comprises a further processing device which is configured to further process the gradient signal, wherein the further processing is carried out by sending the gradient signal to a regulating device which is present in the vehicle and is configured to further process the gradient signal and to adapt the dynamic parameters on the basis of the received and processed gradient signal, or wherein the further processing is carried out by sending the gradient signal to an external processing device which is configured to further process the gradient signal into control signals and to send it back to the further processing device in the vehicle in order to adapt the dynamic parameters of the vehicle.

7. Method for determining a gradient signal in a vehicle, having the steps of: First step (S1): determining the position of the vehicle in an absolute system (XYZ) at least at a first point in time (t=0) and at a second point in time (t=1) and using this to determine, on the basis of the geometrically known position (L1, h1, b1, α) of the first laser distance sensor (2), the distance (L) covered as a movement vector (Ga0, Ga1); Second step (S2): determining a differential vector (Ga0,1, Gb0) from the movement vector (Ga0, Ga1) and the vectors of the laser beam, determined at the first and the second point in time (t=0; t=1), from at least one first laser distance sensor (2) which is arranged with an inclination of a predefined angle (α) with respect to the vehicle longitudinal axis (X) on a front side of the vehicle and emits at least one first laser beam at least at the first and the second point in time (t=0; t=1) in the direction of a first measurement point (Pa) in front of the vehicle, and determining a gradient signal therefrom.

8. Method according to Claim 7, having the further step of: Third step (S3): further processing the determined gradient signal.

9. Method according to Claim 8, wherein the further processing is carried out by: - internally calculating a control signal for adapting the dynamic parameters of the vehicle, and carrying out the adaptation, or - sending the gradient signal for external processing and receiving at least one control signal, determined from the gradient signal, for adapting the dynamic parameters of the vehicle, and carrying out the adaptation.

10. Method according to Claim 9, wherein the further processed gradient signal and / or the control signal is / are used to digitize the terrain and / or is / are made available to other vehicles.