DE102021208811B3 - Evaluation device for detecting an inclination of a ground that can be driven on by an industrial truck, industrial truck with it and method for it - Google Patents

Abstract

An evaluation device (10) for detecting an inclination (20) of a subsurface (40) that can be driven over by an industrial truck (30) is proposed, the evaluation device (10) comprising: a measuring device (12) for measuring at least one distance (50) between a surface section (44) of the base (40) and the measuring device (12) of the industrial truck (30); and a detection device (14) for detecting an inclination (20) of the ground (40) based on the measured distance (50) and a reference value (52). An industrial truck (30) comprising the evaluation device is also proposed. A method for detecting an inclination (20) of a subsurface (40) that can be driven over by an industrial truck (30) is also proposed, the method comprising: a measuring step (S1) for measuring at least one distance (50) between a surface section (44) of the subsurface (40) and a measuring device (12) of the industrial truck (30); and a detection step (S2) for detecting an inclination (20) of the ground (40) based on the measured distance (50) and a reference value.

Description

technical field

The present invention relates to an evaluation device for detecting an inclination of a ground that can be driven over by an industrial truck. Furthermore, the invention relates to an industrial truck with the evaluation device. The invention also relates to a method for detecting an inclination of a ground that can be driven over by an industrial truck.

State of the art

From the document DE 10 2016 110 461 A1 a method for detecting an incline of a roadway for a motor vehicle, a driver assistance system and a motor vehicle are known. According to the method, a roadway area is divided into a predetermined number of strips and environmental points detected by a detection device of the vehicle are assigned to the strips. A height value is determined for the strips, or a slope value between the associated height values for pairs of strips. If at least one of the gradient values exceeds a predetermined gradient limit value, a gradient of the roadway is detected.

From the document DE 10 2017 209 695 A1 a method for controlling a work platform is known, the work platform having at least one distance sensor assigned to a wheel of the work platform. In the method, a transit time of a measurement beam, which represents a beam emitted by the distance sensor at an angle onto a roadway of the working platform, is determined. The running time determined in this way is compared with a reference running time in order to determine a change in the angle of inclination of the work platform. Finally, depending on the change in the angle of inclination, a control signal for controlling the work platform is output.

Presentation of the invention

In one aspect, the invention relates to an evaluation device for detecting an inclination of a ground that can be driven over by an industrial truck.

An industrial truck can be a mobile transport device for transporting goods. The industrial truck has a load-carrying element for receiving a load, for example goods to be transported. The industrial truck can be mobile, for example, by means of rollers. The industrial truck can also have at least one motor for driving the industrial truck. This can be an internal combustion engine or an electric motor. The motor can be activated by means of control signals in order to drive the industrial truck. An industrial truck can therefore be understood to mean, for example, a lift truck, a forklift or a wheel loader.

A subsurface that can be driven over by an industrial truck can be a subsurface that is traveled over by the industrial truck when it is in an operating state. Furthermore, the ground that can be driven over by an industrial truck can also be a ground on which the industrial truck can be parked when it is at rest. The industrial truck can be in an idle state when it is not being moved or when an engine of a motorized industrial truck is switched off. For example, the ground that can be driven on can be the floor of a warehouse or factory building, on which the industrial truck transports a load that has been picked up and is then parked in the idle state. Alternatively or additionally, the drivable subsurface can be a loading or distribution yard located outside the warehouse or factory building, on which goods to be transported can be moved by the industrial truck during a loading process.

An inclination of the subsoil can be understood, for example, as a section of the floor of the warehouse or factory hall or the loading or distribution yard that rises with respect to an extension direction of the subsoil. In other words, the ground can be inclined if the industrial truck has to cope with a difference in height relative to sea level while traveling on the ground. Accordingly, after driving on an inclined surface, the industrial truck can be at a different sea level than at the start of driving on the inclined surface. The evaluation device can be arranged on the industrial truck. Alternatively, the evaluation device can be spaced apart from the industrial truck and can be part of a higher-level control device of the industrial truck.

The evaluation device includes a measuring device for measuring at least one distance between a surface section of the ground and the measuring device of the industrial truck. The measuring device is arranged on an upper end section of a load handling element of the industrial truck, ie above the head of a driver of the industrial truck when the driver is in a driving position. In particular, therefore, a vertical distance between the measuring front direction to the ground must be greater than 2 m. The measuring device can therefore measure the at least one distance at an angle with respect to a perpendicular. For example, the measuring device can measure the at least one distance using acoustic or optical signal processing. In this case, the measuring device can detect distance values optically or acoustically, which can be converted into distance data by means of electronic signal processing. The measuring device can use this distance data to measure the at least one distance. The at least one distance can specify a distance, for example in millimeters, centimeters or meters, between the surface section of the ground and the measuring device of the industrial truck. The surface section of the ground can designate a section of the ground that can be driven over by the industrial truck, which can be brought into contact with the rollers of the industrial truck. In particular, the surface section can be arranged in front of the industrial truck in a direction of travel of the latter. In other words, the surface section can not be arranged under the industrial truck, but rather in the vicinity of the industrial truck.

The evaluation device also includes a detection device for detecting an inclination of the ground based on the measured distance and a reference value. The detection device can be any type of electronic circuit suitable for receiving electrical signals and performing electronic signal conversion. For example, the recognition device can be a processor or a controller. In this case, the detection device can directly receive and further process the distance data collected by the measuring device. Alternatively, the detection device can already receive pre-processed distance data, for example from the measuring device.

The reference value can also be a distance, for example in millimeters, centimeters or meters. In this case, the measured distance and the reference value can be directly compared. Alternatively, the reference value may be specified in a unit of measure other than a unit of length, such as an absolute value, a percentage or a number of degrees. In this case, either the measured distance, the reference value, or both can be converted to the same unit of measure in order to be able to compare the measured distance and the reference value. Alternatively, the measured distance and the reference value can also be specified in different units of measurement that can be converted into one another. The reference value can be predetermined, for example. Alternatively, the reference value can be determined in a previous measurement step. In particular, the reference value can be provided with a tolerance range. In this case, the detection device detects an inclination if the measured distance and the reference value differ from one another by more than the tolerance range.

The proposed evaluation device thus makes it possible, on the basis of distance measurements that are easy to carry out, to detect an inclination of a subsurface that can be driven over by an industrial truck before this subsurface is actually driven on. Traveling on an incline with an industrial truck, particularly with a load on it, can result in the truck or the load being lifted tipping over. Furthermore, driving down a slope with a load taken up in a downward direction of the slope can lead to a loss of the load, for example due to a downhill force acting on the load. Finally, turning the truck over on an incline can cause the truck to tip over.

The accidents described above can lead to property damage or personal injury. If, on the other hand, a tilt is detected early, these accidents can be avoided. By means of the proposed evaluation device, it is possible in a particularly simple manner to detect an inclination of a subsurface that can be driven over by an industrial truck, even before driving over it. Furthermore, measuring devices for measuring a distance are very inexpensive and easy to obtain. The operational safety of an industrial truck can therefore be improved using simple and inexpensive means.

According to one specific embodiment, the evaluation device can also include an output device for outputting a control signal to the industrial truck when the inclination has been detected. The control signal may include at least one of the following: a warning signal; and a restriction signal for restricting the driving behavior of the industrial truck. A warning signal can be output, for example, optically in the form of a warning lamp, acoustically in the form of a warning tone or using a warning on a display device of the industrial truck. A driving behavior of the industrial truck can be restricted, for example, to avoid an accident. In this case, the travel speed of the truck can be reduced. Alternatively or additionally, a driving behavior of the be restricted to prevent the truck from tipping over. In this case, a rotational speed about an axis of rotation of the industrial truck can be reduced when the same is turned. By means of the output device, in addition to detecting a tilt, the driver of the industrial truck can be warned of the detected tilt or driving over the detected tilt with the industrial truck can be restricted. This can further increase the operational safety of the industrial truck.

According to a further embodiment, the measuring device can also be set up to measure a reference distance between the measuring device and a reference section of the ground that can be driven on by the industrial truck when the industrial truck is in a calibration state. In this case, the detection device can detect an inclination if the reference distance deviates from the measured distance. A calibration state of the industrial truck can be a state after it has been put into operation and before the industrial truck starts traveling. In this calibration state, the industrial truck can be located in particular on a section of the ground that has a flat surface. For example, a surface can be flat if a difference in elevation along all directions of the surface is less than a predetermined threshold. The reference section of the ground can be arranged in front of the truck in the direction of travel of the truck. A distance of the reference section from, for example, a front section of the industrial truck can be set by a driver of the industrial truck. In other words, the driver of the industrial truck can determine how far the reference section to be measured is from the industrial truck. The reference section can also have a planar surface as defined above.

As already described above, the reference distance can be provided with a tolerance range. If the deviation of the measured distance is within the tolerance range of the reference distance, it can be provided that an inclination is not recognized by the recognition device. The calibration of the measuring device, in particular with regard to a flat surface, offers the advantage that a desired reference distance can be defined, on which the detection of the inclination is based. Accordingly, the evaluation device can be adapted to different surface properties of a subsurface that can be driven over by an industrial truck. Alternatively or additionally, the evaluation device can be adapted to various user specifications.

According to a further embodiment, a position of the measuring device relative to a coordinate system of the industrial truck can be specified. Furthermore, the reference section of the drivable subsurface can be determined by a coordinate axis of the coordinate system of the industrial truck in the calibrated state. The reference distance can be specified by a straight line that intersects the reference section at a reference point, and the measured distance can be specified by a straight line that intersects the surface section of the subsoil at a measurement point. The coordinate system of the industrial truck can in particular be a Cartesian coordinate system, the origin of which can be the center of gravity of the industrial truck. The coordinate system can be defined in the calibration state of the industrial truck. The location of the measuring device can be predetermined with respect to a position or an orientation of the measuring device in the coordinate system. The reference section of the drivable subsurface can in turn be a flat surface according to the above definition, which extends with a longitudinal direction along the coordinate axis of the coordinate system of the industrial truck. This flat surface can be intersected at the reference point by a straight line originating from the position of the measuring device. In an analogous manner, the surface section of the subsoil can be intersected at the measuring point by the straight line originating from the position of the measuring device. In particular in the calibration state, the position of the reference point and the position of the measuring point can be identical. However, if the industrial truck moves towards a surface section that has a slope, the position of the measuring point and the position of the reference point can shift within the coordinate system.

In this embodiment, a first connecting straight line can be defined by the reference point and the origin of the coordinate system of the industrial truck. Furthermore, a second connecting straight line can be defined by the measuring point and the origin of the coordinate system of the industrial truck. In this embodiment, the measuring device can also be set up to determine an angle between the first connecting straight line and the second connecting straight line from the measured distance. If the measured surface section of the subsoil is the reference section, the first connecting line and the second connecting line can run parallel.

However, the position of the measurement point and the position of the reference point shift within the coordinate system as described above, the arrangement of the first connecting straight line and the second connecting straight line within the coordinate system is also shifted relative to one another. The measured distance can therefore be representative of a displacement of the first connecting straight line and the second connecting straight line relative to one another, ie an arrangement of the first connecting degrees and the second connecting straight line at an angle. The angle between the measured surface section and the reference section can therefore be determined by measuring the changed distance.

In this embodiment, a reference angle can represent the reference value and the detection device can also be set up to detect an inclination of the ground when the specific angle deviates from the reference angle. The reference angle can be predetermined. Alternatively, the reference angle can be determined based on previous measurements of an inclined surface. The angle determined according to the above procedure can be representative of a degree of inclination, ie an incline of the surface section. An angle can therefore be determined by means of simple distance measurements, which is representative of an incline of the surface section to be traveled on.

According to a further embodiment, the evaluation device can also include a second measuring device, which is set up to measure at least a second distance between a second surface section of the subsoil and the second measuring device. The detection device can also be set up to detect an incline of the ground based on the measured distance, the measured second distance, the first reference value and a second reference value. The second measuring device can be arranged symmetrically to the first measuring device on a front section of the industrial truck. Analogous to this, the second surface section can be arranged symmetrically to the surface section in front of the industrial truck in a direction of travel of the latter. For example, the surface section and the second surface section can be arranged at the same distance and in the same orientation with respect to an axis of symmetry of the industrial truck. In particular, the second measuring device, the second distance and the second surface section can be configured analogously to the measuring device, the measured distance and the surface section. The detection of an inclination of a second surface section of the ground that can be driven on by the industrial truck makes it possible to simultaneously measure a larger area of the ground that is to be driven on for the detection of a gradient. The detection of an inclination and thus the operational safety of the industrial truck can be improved as a result.

The second measuring device can also be set up to measure a second reference distance between the second measuring device and a second reference section of the ground that can be traveled over by the industrial truck when the industrial truck is in the calibration state. The detection device can also be set up to detect an inclination when the second reference distance deviates from the measured second distance. The second reference distance and the second reference section of the subsoil can in particular be configured analogously to the reference distance and the reference section of the subsoil. With regard to the specific features and advantages, reference is made to the above statements.

According to a further embodiment, a position of the second measuring device relative to the coordinate system of the industrial truck can be specified. Furthermore, the second reference section of the drivable subsurface can be determined by a second coordinate axis of the coordinate system of the industrial truck in the calibrated state. In particular, the second coordinate axis of the coordinate system can be aligned perpendicular to the coordinate axis along which the reference section of the subsoil extends in a longitudinal direction.

In this embodiment, the second reference distance can be specified by a straight line which intersects the second reference section at a second reference point. Furthermore, the measured second distance can be specified by a straight line which intersects the second surface section of the subsoil at a second measuring point. In particular, the second reference distance, the second reference section, the second reference point and the second measuring point can be configured analogously to the reference distance, the reference section, the reference point and the measuring point. With regard to the specific features and advantages, reference is made to the above statements.

In this embodiment, a third connecting straight line can be defined by the first reference point and the second reference point. Furthermore, a fourth connecting straight line can be defined by the first measurement point and the second measurement point. Furthermore, the measuring device can also be set up to calculate a second angle between the third th straight connecting line and the fourth straight connecting line. As already described above, driving on an inclined surface can also lead to a displacement of the second reference point and the second measurement point or a displacement of the third connecting straight line and the fourth connecting straight line at an angle to one another. This angle can be determined from a measurement of the distance and the second distance. The second angle can in particular be arranged in a plane perpendicular to the first angle. Accordingly, the second angle can be representative of an inclination of the ground transverse to a direction of travel of the industrial truck.

In this embodiment, a second reference angle can represent the second reference value and the detection device can also be set up to detect an inclination of the ground when the determined second angle deviates from the second reference angle. Both an inclination in the direction of travel of the industrial truck and an inclination transverse to the direction of travel of the industrial truck can be detected by means of two distance measurements that can be carried out easily and inexpensively. The operational safety of the industrial truck can be further improved as a result.

According to a further embodiment, the calibration state of the industrial truck can be defined by arranging the industrial truck on an essentially slope-free reference surface of the ground. In this case, the reference surface of the subsurface can be without an incline in relation to a standing surface of the industrial truck on the subsurface to be traveled over. In other words, the reference surface can be arranged parallel to a driving plane of the industrial truck spanned by two coordinate axes of the coordinate system of the industrial truck. Calibrating the measuring device or the second measuring device with respect to the essentially slope-free reference surface of the ground offers the advantage that when determining the reference distance or the second reference distance, a slope of the standing surface of the industrial truck does not have to be taken into account. The reference distance or the second reference distance accordingly represents a reliable comparison value for a surface without an incline. The accuracy of the incline detection can be improved as a result.

In this embodiment, a surrounding area around the industrial truck can be specified in the reference surface. The measuring device can also be set up to determine the angle taking into account the surrounding area. The surrounding area can, for example, define an area which has a predefined distance around the industrial truck. Alternatively or additionally, the surrounding area can define an area which has a substantially slope-free surface according to the definition above. In other words, it can be assumed that a surrounding area around the industrial truck, which has no height difference, for example due to the dimensions of the industrial truck, possibly with an additional predefined distance. It can thus be assumed that a detected inclination is not present within this surrounding area, but rather between the measurement section and the surrounding area. The angle between the first connecting straight line and the second connecting straight line can therefore be determined taking into account a vehicle environment, for example with regard to a position of the industrial truck in the surrounding area. The accuracy of detecting a tilt can be improved as a result.

According to a further embodiment, the edge points of the surrounding area can have a height of zero with respect to the reference surface. In other words, the edge points of the surrounding area can lie in the travel plane of the industrial truck spanned by two coordinate axes. The surrounding area can thus also have an essentially slope-free surface. The angle between the first connecting straight line and the second connecting straight line can therefore be determined taking into account an essentially slope-free area surrounding the industrial truck. The accuracy of the inclination detection can be further improved as a result.

According to a further embodiment, a determination area of the reference surface including the surrounding area of the industrial truck can be predetermined. The measuring device can also be set up to determine an additional angle between a partial area of the determination area and a boundary line of the surrounding area from the measured distance. For example, the partial area of the determination area can border on the surrounding area. The additional angle can be determined between a boundary line of the surrounding area and the plane spanned by the partial area. Furthermore, the detection device can be set up to detect an additional inclination of the partial area of the subsoil if the determined additional angle deviates from an additional reference angle. With regard to the determination of the additional angle and the additional reference angle, reference is made to the statements above and those that follow referenced to the working examples. This embodiment of the evaluation device makes it possible to detect an inclination of the surroundings of the industrial truck by means of simple distance measurements. As a result, the accuracy of the inclination detection can be further improved. This can increase the operational safety of the industrial truck.

In this embodiment, the output device can also be set up to output a control signal for generating a graphical representation of the at least one partial area together with the detected partial inclination on a display device of the industrial truck. For example, the at least one partial area and the associated recognized partial inclination can be displayed on the display device of the industrial truck by means of color coding. The color coding can be representative of a steepness of the slope, ie a slope of the same. Driving in a specific direction in which a particularly steep incline has been detected can be avoided in this way. This can improve the operational safety of the industrial truck.

According to a further embodiment, the detection device can also be set up to carry out the detection of the inclination taking into account previous distance measurements. The preceding distance measurements can be carried out between the measuring device and a surface section of the subsoil on which the industrial truck is driving. In this embodiment, the detection device can also be set up to detect gradients traveled on based on the previous distance measurements and at least one reference value. The detection device can also be set up to detect an incline of the ground on which the industrial truck is driving if a total of the inclines on which the truck is driving exceeds a threshold value. The previous distance measurements can be temporarily stored in the evaluation device and taken into account in a current inclination detection. For example, an inclination of surface sections of the subsoil that have already been traveled on can be recognized from the previous distance measurements according to the procedure described above. When recognizing an inclination of a surface section of the subsoil that is currently to be traveled on, these previously recognized inclinations of surface sections of the subsoil that have already been traveled on can be taken into account by the detection device. In particular, the previously recognized inclinations can be summed up and compared with a threshold value. If the sum of the previously detected inclinations is above the threshold value, it can be assumed with sufficient probability that the industrial truck is actually located on a surface section of the ground that has an inclination. The accuracy of the detection of an inclination of a surface section that is currently to be traveled on can be improved as a result.

According to one specific embodiment, the evaluation device can also include an inclination detection device for detecting an inclination of the ground on which the industrial truck is driving. The detection device can also be set up to carry out the detection of the inclination based on the inclination detected by the inclination detection device. In particular, the inclination of the subsurface currently being traveled over, detected by the inclination detection device, and the inclination of the subsurface to be traveled over subsequently, detected by the detection device, can be summed up. In this way, an overall gradient of the subsoil to be traveled on subsequently can be determined. The inclination detection device can be, for example, an inclination sensor arranged on the industrial truck. The inclination sensor can receive inclination values of the industrial truck in relation to a reference value and convert these into inclination data of the industrial truck using electronic signal processing. This inclination data can be taken into account by the identification device when recognizing the inclination of the surface section of the subsoil to be traveled on. As a result, the accuracy of the inclination detection can be improved and the operational safety of the industrial truck can thereby be increased.

In this embodiment, the evaluation device can also detect a validation device for validating an inclination of the ground on which the industrial truck is driving, detected by the detection device. The validation can take place taking into account the inclination detected by the inclination detection device. For example, the inclination of a surface section of the subsoil that is to be traveled over, detected by the detection device, can be stored in the evaluation device and compared with the inclination data recorded by the inclination sensor for this surface section during subsequent travel. In this way, the inclination detected for the respective surface section can be subsequently validated or adjusted. The accuracy of the detection of an overall inclination of the subsoil can be improved as a result.

According to a further embodiment of the evaluation device, the calibration state of the industrial truck can also be defined by the end of an idle state of the industrial truck. Alternatively or additionally, the calibration status of the industrial truck can also be defined by a change in the position of at least one hydraulic component of the industrial truck. For example, when the engine of the industrial truck is started, the evaluation device can generate a visual or audible indication to the driver of the industrial truck that the industrial truck must be calibrated before the start of a journey. Alternatively, the industrial truck can also be calibrated automatically by the evaluation device before the start of a journey. The hydraulic component of the industrial truck can be, for example, the load handling element or a driver's seat of the industrial truck. Changing the load-carrying element, in particular by lifting a load that has been picked up, can lead to a change in the position of the center of mass in the coordinate system of the industrial truck. In this case, it may be necessary to carry out the calibration again, for example in order not to falsify the determination of the angle. When changing the driver's seat, in particular the seat height of a driver, it may be necessary to change the distance between the measuring point of the measuring device on the surface section of the ground and the industrial truck. This change can be made by a driver of the industrial truck in the calibration state. By repeating or re-performing the calibration state, the evaluation device can be adapted to different operating situations or different user specifications. As a result, the applicability or the user-friendliness of the inclination detection can be improved.

According to a further embodiment, the evaluation device can also include a reference light source. The measuring device can be mounted on the industrial truck in such a way that a measuring range of the measuring device is overlaid with a light field of the reference light source. Provision can be made to use the reference light source only when the measuring device is installed. Alternatively, the reference light source can be switched on when the industrial truck is in the calibration state in order to display its light field. If the measuring device is an acoustic measuring device, superimposing the light field of the reference light source with the measuring range of the measuring device can make the acoustic measuring range of the same visible to a fitter or driver of the industrial truck. If necessary, the alignment of the measuring device can be adjusted in this way. This can improve the accuracy of the tilt detection.

According to one embodiment, the detection device can be included in the measuring device. According to an alternative embodiment, the detection device can be arranged separately from the measuring device on the industrial truck. In this embodiment, the detection device can be set up to receive signals from the measuring device by means of a communication interface. In the first embodiment, the detection device can be arranged in the measuring device... This can facilitate installation and retrofitting, since the measuring devices can operate autonomously. If, on the other hand, the detection device is provided separately from the measuring device, the detection device can receive the measurement data from a plurality of measuring devices and evaluate them together to detect an inclination. This can improve the accuracy of the tilt detection. The evaluation device can therefore be adapted to different types of industrial trucks or different operational situations of industrial trucks.

According to a second aspect, the invention relates to an industrial truck, which can include an evaluation device according to the first aspect.

According to a third aspect, the invention relates to a method for detecting an inclination of a ground that can be driven over by an industrial truck. The method includes a measuring step for measuring at least one distance between a surface section of the ground and a measuring device of the industrial truck. The method also includes a detection step for detecting a slope of the ground based on the measured distance and a reference value.

character list

• 1a and 1b show a schematic of an industrial truck with an evaluation device for detecting an inclination of a surface to be traveled over by the industrial truck according to a first embodiment of the invention.
• 2a and 2 B show schematically an industrial truck with an evaluation device for detecting an incline of a surface to be traveled over by the industrial truck according to a second embodiment of the invention.
• 3a and 3b show schematically an industrial truck with an evaluation device for detecting an inclination of a subsurface to be traveled over by the industrial truck according to a third embodiment of the invention.
• 4 shows a schematic of an industrial truck with an evaluation device for detecting an incline of a subsurface on which the industrial truck is driving, according to a fourth embodiment of the invention.
• 5 shows a schematic of an industrial truck with an evaluation device for detecting an incline of a surface on which the industrial truck is driving, according to a fifth embodiment of the invention.
• 6 shows a flow chart with steps of a method for detecting an incline of a subsurface on which an industrial truck is driving according to an embodiment of the invention.

Detailed Description of Embodiments

1a shows schematically an industrial truck in the form of a forklift truck 30 in a calibration state. The forklift truck 30 drives on a subsurface 40. The forklift truck 30 has an evaluation device 10 for detecting an inclination of a surface section of the subsurface 40. The evaluation device 10 includes a measuring device 12 which, when the forklift truck 30 is in the calibrated state, measures a reference distance 52 between the measuring device 12 and a reference section 42 of the subsoil. Furthermore, the evaluation device 10 includes a detection device 14 for detecting an inclination of a surface section. The inclination detection by the detection device 14 is in the 1 b explained.

1b shows schematically the forklift 30 of FIG 1a in an operating state in which the forklift truck 30 drives over the ground 40 . The measuring device 12 measures a distance 50 between a surface section 44 and the measuring device 12. The measured distance 50 deviates from the reference distance 52 of the 1a away. Based on this deviation, the detection device 14 of the evaluation device 10 detects an inclination 20 of the surface section 44 according to the procedure described above.

2a shows schematically the forklift 30 with an evaluation device 10 according to a second embodiment. In the 2a the forklift 30 is again in a calibration state. In this calibration state, the measuring device 12 again measures a reference distance 52 between the measuring device 12 and the reference section 42 of the subsurface 40. Here, a straight line emanating from the measuring device 12 intersects the reference section 42 at a reference point 54. In the embodiment of 2a the position of the measuring device 12 relative to a coordinate system K of the forklift truck 30 is predetermined.

2 B shows schematically the forklift 30 of FIG 2a in an operating state in which the forklift truck 30 drives over the ground 40 . The measuring device 12 measures the distance 50 between the surface section 44 and the measuring device 12. A straight line emanating from the measuring device 12 intersects the surface section 44 at a measuring point 56. A first connecting straight line VG1 is defined by the reference point 54 and the origin of the coordinate system K. Furthermore, a second connecting straight line VG2 is defined by the measuring point 56 and the origin of the coordinate system K. In the embodiment of 2 B the measuring device 12 can determine an angle 60 between the first connecting straight line VG1 and the second connecting straight line VG2 from the measured distance 50 .

3a shows schematically the forklift 30 with an evaluation device 10 according to a third embodiment. The evaluation device 10 has a second measuring device 16 . In the 3a the forklift 30 is again in a calibration state. In this calibration state, the second measuring device 16 then measures a reference distance 50′ between the measuring device 16 and a second reference section 44′ of the subsurface 40. A straight line emanating from the second measuring device 16 intersects the second reference section 44 at a second reference point 54′. In the embodiment of 3a the position of the second measuring device 16 relative to the coordinate system K of the forklift truck 30 is predetermined.

3b shows schematically the forklift 30 of FIG 3a in an operating state in which the forklift truck 30 drives over the ground 40 . The second measuring device 16 measures the distance 50′ between the second surface section 44′ and the second measuring device 16. A straight line emanating from the second measuring device 16 intersects the second surface section 44′ at a second measuring point 56′. A third connecting straight line VG3 is defined by the first reference point 54 and the second reference point 54'. Furthermore, a fourth connecting straight line VG4 is defined by the first measuring point 56 and the second measuring point 56′. In the embodiment of 3b can the second measuring device 16 from the measured second distance 50 'a second angle 60' between the third connecting straight line Determine VG3 and the fourth connecting straight line VG4. Furthermore, the detection device 14 is set up to detect an inclination 20 of the second surface section 44′ if the second angle 60′ deviates from a predetermined reference angle.

4 shows schematically the forklift 30 with an evaluation device 10 according to a fourth embodiment. In the 4 a surrounding area 46 around the forklift truck 30 is specified. Surrounding area 46 has a planar surface as defined above. The evaluation device 10 can recognize the angle 60 taking into account the surrounding area 46 . Due to the flat surface of the surrounding area 46, the accuracy of the determination of the angle 60 can be improved as explained above.

5 shows schematically the forklift 30 with an evaluation device 10 according to a fifth embodiment. In the 5 a determination area 48 including the surrounding area 46 around the forklift truck 30 is predetermined. The determination area has a partial area 48 ′, which borders on a boundary line 46 ′ of the surrounding area 48 . The evaluation device 10 can detect an additional inclination 20 ′ of the partial area 48 ′ of the determination area 48 . The detected additional inclination can be output on a display device of the forklift truck 30 .

In 6 Steps are shown for carrying out the method for detecting an inclination of a ground that can be driven on by an industrial truck. In particular, the method for detecting an incline 20 of the ground 40 traveled over by the forklift truck 30 can be used. The method begins with a measuring step S1 for measuring at least one distance between a surface section of the ground and a measuring device of the industrial truck. In a detection step S2, an inclination of the ground is detected based on the measured distance and a reference value as described above.

The evaluation device 10 was based on the 1 until 6 shown using a forklift truck 30 as an example. However, further embodiments of an industrial truck, which travels over an inclined surface, are also covered by the proposed method.

Reference List

10

evaluation device

12

measuring device

14

detection device

16

second measuring device

20, 20'

inclination, additional inclination

30

Industrial truck, forklift

40

drivable ground

42

reference section

44, 44`

surface section

46

surrounding area

46'

Boundary line of the surrounding area

48

destination area

48'

Partial area of the determination area

50, 50'

measured distance

52, 52'

reference distance

54, 54'

reference point

56, 56'

measuring point

60, 60'

angle

70

tilt sensor

VG1, VG2, VG3, VG4

connecting lines

p 1

measuring step

S2

detection step

Claims (23)

Evaluation device (10) for detecting an inclination (20) of a subsurface (40) that can be driven over by an industrial truck (30), the evaluation device (10) comprising: a measuring device (12) for measuring at least one distance (50) between a surface section (44) of the ground (40) and the measuring device (12) of the industrial truck (30); and a detection device (14) for detecting an inclination (20) of the ground (40) based on the measured distance (50) and a reference value (52), wherein the measuring device (12) is arranged on an upper end section of a load-carrying element of the industrial truck (30). Evaluation device (10) after claim 1 , further comprising an output device for Outputting a control signal to the industrial truck (30) when the inclination (20) has been detected, the control signal comprising at least one of the following: a warning signal; and a restriction signal for restricting the driving behavior of the industrial truck (30). Evaluation device (10) after claim 1 or 2 , wherein the measuring device (12) is also set up to determine a reference distance (52) between the measuring device (12) and a reference section (42) of the ground (40) that the industrial truck (30) can drive over when the industrial truck (30) is in a calibration state measure, wherein the detection device (14) detects an inclination (20) when the reference distance (52) deviates from the measured distance (50). Evaluation device (10) after claim 3 , wherein a position of the measuring device (12) relative to a coordinate system (K) of the industrial truck (30) is specified, wherein the reference section (42) of the drivable subsurface (40) is defined by a coordinate axis of the coordinate system (K) of the industrial truck (30). calibration state is determined, the reference distance (52) being specified by a straight line which intersects the reference section (42) at a reference point (54), the measured distance (50) being specified by a straight line which intersects the surface section (44) of the underground (40) at a measuring point (56), with a first connecting line (VG1) being defined by the reference point (54) and the origin of the coordinate system (K) of the industrial truck (30), with a second connecting line (VG2) being defined by the Measuring point (56) and the origin of the coordinate system of the industrial truck (30) is defined, wherein the measuring device (12) is further set up to measure from the a distance (50) to determine an angle (60) between the first connecting straight line (VG1) and the second connecting straight line (VG2), with a reference angle representing the reference value, and wherein the detection device (14) also for detecting an inclination (20) of the Subsoil (40) is set up when the specific angle (60) differs from the reference angle. Evaluation device (10) according to one of the preceding claims, further comprising a second measuring device (16) which is set up to measure at least a second distance (50') between a second surface section (44') of the substrate (40) and the second measuring device ( 16) to measure; wherein the detection device (14) is further set up to detect an incline (20) of the ground (40) based on the measured distance (50), the measured second distance (50`), the first reference value and a second reference value. Evaluation device (10) after claim 5 , wherein the second measuring device (12) is also set up to, in the calibration state of the industrial truck (30), a second reference distance (52') between the second measuring device (16) and a second reference section (42') of the industrial truck (30) to measure drivable subsoil (40), wherein the detection device (14) detects an inclination (20) when the second reference distance (52 ') from the measured second distance (50') differs. Evaluation device (10) after claim 6 , wherein a position of the second measuring device (16) relative to the coordinate system (K) of the industrial truck (30) is specified, wherein the second reference section (42') of the drivable subsurface (40) is defined by a second coordinate axis of the coordinate system (K) of the industrial truck (30) is determined in the calibration state, the second reference distance (52') being specified by a straight line which intersects the second reference section (42') at a second reference point (54'), the measured second distance (50') passing through a straight line is specified, which intersects the second surface section (44') of the subsurface (40) at a second measuring point (56'), with a third connecting straight line (VG3) through the first reference point (54) and the second reference point (54') is defined, wherein a fourth connecting straight line (VG4) through the first measuring point (56) and the second measuring point (56 ') is defined, wherein the second measuring device (15) is set up to measure from the to determine a second distance (50') a second angle (60') between the third connecting line (VG3) and the fourth connecting line (VG4), wherein a second reference angle represents the second reference value, and wherein the detection device (14) further for detecting an inclination (20) of the ground (40) is set up when the specific second angle (60 ') deviates from the second reference angle. Evaluation device (10) according to one of claims 3 until 7 , wherein the calibration state of the industrial truck (30) is defined by an arrangement of the industrial truck (30) on a reference surface of the ground (40) that is essentially free of inclination. Evaluation device (10) according to one of Claims 4 until 8th , wherein a surrounding area (46) around the industrial truck (30) in the reference surface (42) is specified, wherein the measuring device (12) is further set up to determine the angle (60) taking into account the surrounding area (46). Evaluation device (10) after claim 8 or 9 , wherein the edge points of the surrounding area (46) have a height of zero with respect to the reference surface. Evaluation device (10) after claim 9 or 10 , wherein a determination area (48) of the reference surface enclosing the surrounding area (46) of the industrial truck (30) is specified, wherein the measuring device (12) is also set up to calculate an additional angle (20') between a partial area from the measured distance (50). (48') of the determination area (48) and a boundary line of the surrounding area (46'), the detection device (14) also being set up to detect an additional inclination of the partial surface (48') of the subsurface (40) if the determined additional angle (20') deviates from an additional reference angle. Evaluation device (10) after claim 11 combined with claim 2 , wherein the output device is also set up to output a control signal for generating a graphical representation of the at least one partial area (48') together with the detected partial inclination on a display device of the industrial truck (30). Evaluation device (10) according to one of the preceding claims, wherein the detection device (14) is also set up to carry out the detection of the inclination (20) taking into account chronologically preceding distance measurements, the chronologically preceding distance measurements between the measuring device (12) and one of the Industrial truck (30) traveled surface section (44) of the subsoil (40) were carried out. Evaluation device (10) after Claim 13 , wherein the detection device (14) is also set up to detect gradients traveled on based on the previous distance measurements and at least one reference value, the detection device (14) also for detecting a gradient (20) of the ground (40) traveled on by the industrial truck (30) is set up when a sum of the gradients traveled exceeds a threshold value. Evaluation device (10) according to one of the preceding claims, further comprising an inclination detection device (70) for detecting an inclination (20) of the ground (40) traveled over by the industrial truck (30), wherein the detection device (14) is also set up to detect of the inclination (20) based on the inclination (20) detected by the inclination detection device (70). Evaluation device (10) after claim 15 , further comprising a validation device for validating an inclination (20) detected by the detection device (14) of the ground (40) traveled over by the industrial truck (30), the validation taking into account the inclination (20) detected by the inclination detection device (70). . Evaluation device (10) according to one of Claims 8 until 16 , wherein the calibration state of the industrial truck (30) is further defined by ending an idle state of the industrial truck (30). Evaluation device (10) according to one of Claims 8 until 17 , wherein the calibration state of the industrial truck (30) is further defined by a change in the position of at least one hydraulic component of the industrial truck (30). Evaluation device (10) according to one of the preceding claims, further comprising a reference light source, wherein the measuring device (12) can be mounted on the industrial truck (30) in such a way that a measuring range of the measuring device (12) is superimposed with a light field of the reference light source. Evaluation device (10) according to one of the preceding claims, wherein the detection device (14) is comprised by the measuring device (12). Evaluation device (10) according to one of Claims 1 until 19 , wherein the detection device (14) is arranged separately from the measuring device (12) on the industrial truck (30), and wherein the detection device (14) is set up to receive signals from the measuring device (12) by means of a communication interface. Industrial truck (30), comprising an evaluation device according to one of Claims 1 until 21 . Method for detecting an inclination (20) of a subsurface (40) that can be driven over by an industrial truck (30), the method comprising: a measuring step (S1) for measuring at least one distance (50) between a surface section (44) of the subsurface (40) and a measuring device (12) of the industrial truck (30); and a detection step (S2) for detecting an inclination (20) of the ground (40) based on the measured distance (50) and a reference value (52), the measuring device (12) being arranged on an upper end section of a load handling element of the industrial truck (30). is.

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