Method for controlling the milling depth of a ground milling machine, and ground milling machine

Abstract

The invention relates to a method for controlling the milling depth of a ground milling machine having a machine frame supported on traveling elements and a height-adjustable milling drum which can be adjusted vertically relative to a subsurface, and to a ground milling machine, in particular for carrying out the method.

Description

METHOD FOR CONTROLLING THE MILLING DEPTH OF A FLOOR MILLING MACHINE AND FLOOR MILLING MACHINE

[0001] The invention relates to a method for controlling the milling depth of a soil milling machine with a machine frame supported by driving devices and a milling drum that is height-adjustable relative to a soil surface in the vertical direction, as well as a soil milling machine, in particular for carrying out this method.

[0002] Soil milling machines of the present type are typically used in road construction for road rehabilitation, specifically for removing the road surface to a desired milling depth. It is known to lower the working unit, which is designed as a milling drum rotatable horizontally and transversely to the working direction, into the subsoil to achieve the desired milling depth by means of a height adjustment relative to the subsoil. For this purpose, the milling drum, particularly within a milling drum housing, can be mounted on the machine frame of the soil milling machine and, together with the frame, adjustable in the vertical direction by means of suitable lifting devices. Such lifting devices can, for example, be lifting columns that connect drive units standing on the subsoil to the machine frame in a height-adjustable manner, as described, for example, in DE102010050441A1.It is possible for all of the drive units of the soil milling machine to be connected to the machine frame via a lifting mechanism. This is particularly the case with so-called center-rotor milling machines, where the milling drum is arranged between the front and rear drive units in the longitudinal direction of the machine. Such a center-rotor milling machine is described, for example, in DE102015016678 A1. However, it is also known to connect only some of the existing drive units to the machine frame in a height-adjustable manner, as is possible, for example, with so-called rear-rotor milling machines. In particular, such machines can have either only one front drive unit arranged centrally with respect to the machine width or two front drive units mounted relative to each other via a pendulum axis, which, however, are not height-adjustable relative to the machine frame.In such machines, the milling drum is arranged at the rear of the machine at the level of the two rear drive units. Each of the two rear drive units is connected to the machine frame via a lifting device, in particular lifting columns, allowing for height adjustment. It is also known, particularly in these machines, to design at least one of the rear drive units to be pivotable between an inner end position pivoted in front of the milling drum and an outer end position pivoting beside the milling drum. Such a rear-mounted rotary tiller is described, for example, in DE102014010488A1. Purely as a precaution, it should be added here that rear-mounted rotary tillers can also have lifting devices for both the front and rear drive units.

[0003] In operation, it is standard practice to lower the milling drum until it first makes contact with the unmilled soil surface before milling begins. This is also known as "scraping." In this initial position, the milling drum is essentially at zero depth. If the milling drum is lowered further from this point, the distance it travels down determines the current milling depth relative to the adjacent, unmilled soil surface. Controlling the milling depth throughout a milling operation is challenging, especially when there are irregularities in the soil surface or its profile. This can be done entirely manually, but in this case, the result depends heavily on the operator's visual judgment and experience.It is also known to scan the soil area adjacent to the milling drum, for example, using a side plate sliding on the ground and / or a sensor ski. However, these methods often have the disadvantage that irregularities in the soil profile occurring in this area are then more or less copied into the milling bed during the milling process. Furthermore, irregularities in the soil profile can occur in various sizes. Large transverse waves, in particular, can be problematic. A large transverse wave, in this context, is a wave-like structure whose troughs and crests run perpendicular to the milling or working direction of the soil milling machine and whose troughs and crests are at least 1 m, and in particular at least 3 m, apart in the working direction of the soil milling machine.These “hilly” large structures are often not recognized by the soil milling machine and / or a leveling system carried by the soil milling machine and are simply driven over following the wave profile, so that the resulting milling bed also practically has a copy of this wave profile.

[0004] Starting from this, the object of the invention is to provide a way to improve the leveling behavior of a soil milling machine, in particular a cold road milling machine, for compensating for large transverse waves.

[0005] The problem is solved using a method and a soil milling machine according to the independent claims. Preferred embodiments are specified in the dependent claims.

[0006] The method according to the invention therefore relates to a method for controlling the milling depth of a soil milling machine with a machine frame supported by transport devices and a milling drum that is height-adjustable relative to the ground surface in the vertical direction. A specific possible design of a particularly suitable soil milling machine for carrying out this method is described in more detail below in the context of a soil milling machine according to the invention, to which reference is made here.

[0007] In step a), the method according to the invention provides for the setting of a target milling depth. This can, for example, be manually specified by an operator and entered via an operating device and transmitted to a control unit. It can also be specified by an assistance system. The reference point for the target milling depth is, in particular, a ground surface on which the milling drum is currently resting, for example, the zero position determined by scraping. Starting from this ground surface, the target milling depth thus initially specifies how far the milling drum should penetrate into the subsoil, in particular in a direction radial to the axis of rotation downwards. The target milling depth is therefore a distance specification indicating the distance over which the milling drum should engage the subsoil with respect to at least one point of an unmilled initial surface.The milling depth typically extends perpendicular to the unmilled surface.

[0008] In step b), which can occur before, simultaneously with, or after step a), a soil surface detection device is used to perform a contactless spatial measurement of the soil surface extending in front of the soil milling machine in the direction of its work and lying within a detection range. The soil surface detection device is thus part of the soil milling machine and is carried along by it, particularly during milling operations. The detection range refers to the area of ​​the soil surface that is detected by the soil surface detection device. This range remains essentially constant relative to the soil milling machine during operation and is carried along by the machine, but changes relative to the subsoil as the soil milling machine moves in its working direction.Spatial data acquisition refers to a process in which not only two-dimensional image information is collected, but also three-dimensional information about the course and structure of the soil surface within the acquisition area. Because the soil surface acquisition device is mounted on the soil milling machine itself and thus moved along with it during milling operation, the soil milling machine, or rather the known mounting location of the soil surface acquisition device on the machine, can be used as a reference point for a coordinate system. The spatial structure of the soil profile can then be defined relative to this coordinate system. Within this coordinate system, information about the horizontal distance in the milling direction in front of the soil milling machine, the horizontal distance perpendicular to the milling direction, and the position in the vertical direction can be extracted from the spatially acquired area of ​​the soil surface.During milling, the soil milling machine leaves a milling track behind the milling drum, running in the working or milling direction. It is preferred if the detection area, or the part of the detection area considered in the following steps of the method according to the invention, lies in front of the milling drum when viewed in the milling or working direction. This can be located next to the soil milling machine when viewed transversely to the working direction. However, it is preferable if the detection area lies in the direction of travel in front of the milling drum, particularly in front of the soil milling machine, in an extension of the current travel path of the soil milling machine. This ensures that the detection area is located on a soil surface that will soon be traversed by the soil milling machine and milled by the milling drum when milling operations resume.

[0009] If the spatial information for the ground surface recorded within the detection area is available, a digital ground surface profile of the detected ground area is created in step c) based on this information. This profile includes elevation information for at least two reference points. For this purpose, the information determined by the ground surface detection device, particularly in the form of digital data, can be transmitted to a control unit, for example, via a wired or wireless signal transmission line. The control unit can include a suitable computer program for carrying out this step. The digital ground surface profile thus represents a data set containing at least two, preferably a plurality, reference points with at least spatial coordinates relative to the soil milling machine.The at least two reference points ideally lie on a common reference line extending parallel to the direction of travel. They are spaced apart from each other in the milling direction and are located at a defined, i.e., at least known, distance from the milling machine in the direction of travel, in front of the milling drum, and in particular at least partially in front of the milling machine in the direction of travel. The multitude of reference points can extend along one or more reference lines. It can also be represented as a point cloud. In addition to spatial information, the digital ground surface profile can also include other image information, such as color and / or contrast information.

[0010] Building upon step c), step d) involves determining the average height of the digital ground surface profile by incorporating the elevation information of at least two reference points. The "average height" is thus determined by incorporating and averaging the spatial information of the at least two reference points, particularly regarding their elevation or position in the vertical direction, and therefore represents a virtual height of the ground profile along the reference line, which is typically constant. For averaging, an arithmetic mean, a harmonic mean, a geometric mean, a median, or a similar method can be used. It is understood that increasing the number of reference points on the reference line, or increasing the density of reference points on the reference line, increases the accuracy and resolution of the real ground profile in the digital ground surface profile.However, at least one reference point in the vertical direction will always be above the average height and one reference point in the vertical direction will always be below the average height. This step can also be achieved by... The control unit can perform this step, for which the control unit may have a suitable computer program to carry it out.

[0011] Building on the determined average height, in step e), preferably also carried out by a suitable computer program of the control unit, the determined average height can now be used as the height of the, in particular virtual, reference line. This reference line thus runs straight along its extent, unlike the real soil profile with its waves and valleys, and therefore represents an idealized state of the subsoil to be milled.

[0012] This virtual average height is then used in step f), again primarily by a suitable computer program of the control unit, to determine the local difference distance of at least two reference points to the height of the reference line. The local reference distance thus indicates by what amount, particularly perpendicular to the average height, the real reference point lies above or below the average height. In this step, a deviation of the respective reference points from the average height is determined, particularly a deviation that is local or linked to spatial coordinates relative to the milling machine.

[0013] The preceding steps enable, in step g), the milling of the subsoil in the working direction to be carried out, with the target milling depth being adjusted to a local corrective milling depth depending on the current position of the milling drum in the working direction of the soil milling machine and depending on the respective local differential distance to compensate for the respective difference. If a reference point, for example, lies below the average height with a differential distance, this differential distance is subtracted from the original target milling depth, so that the local corrective milling depth is less than the target milling depth. At this point, milling is therefore carried out locally at a shallower depth than actually specified by the target milling depth.If a reference point is located at a difference above the average height, this difference is added to the original target milling depth, resulting in a local correction milling depth greater than the target milling depth. At this point, milling is performed locally at a depth greater than specified by the target milling depth. The areas between individual reference points can be bridged by transition adjustments, for example, by essentially maintaining a constant adjustment of the milling drum's milling depth from a first correction milling depth to a second correction milling depth. The control unit can also determine and regulate the respective correction milling depth, as well as the control and, in particular, the regulation of the milling depth.As a result, this method makes it easier to effectively compensate for transverse waves present in the soil to be milled, especially large ones, or at least to significantly reduce or smooth them with regard to their amplitude.

[0014] It is understood that the method according to the invention is preferably distance-dependent. This means that, simultaneously with the execution of at least one and preferably several of the aforementioned method steps, the distance traveled by the soil milling machine is determined, and / or the distance traveled within a defined time period and / or distance window. Due to the movement of the soil milling machine, the reference coordinate system for the spatial information about the soil surface within the detection range moves together with the soil milling machine in the milling direction. This also changes, in particular, at least the distance between the at least two reference points to the soil milling machine or within the reference coordinate system. It is advantageous if the position of the reference points can be determined by including the distance traveled.The virtual soil profile and the local correction target milling depths are adjusted such that these values ​​and / or parameters are modified by the distance traveled. Specifically, this can mean, for example, that the local correction target milling depth assigned to a reference point, which is initially positioned at a first distance from the soil milling machine, particularly the front cutting edge of the milling drum, when viewed in the milling direction, is reduced by the amount of the determined distance traveled when the soil milling machine moves in the milling direction. Thus, the digital soil profile is continuously updated during milling and adjusted accordingly relative to the distance traveled by the soil milling machine, or updated with regard to the execution of process steps b) to g).This means that, for example, the average height can change during the ongoing milling process and usually will.

[0015] Often, the milling drum, with its leading cutting edge, does not directly connect to the detection area when viewed in the milling direction. This can be due, for example, to the milling drum being covered by part of the rest of the soil milling machine, such as parts of the milling drum housing or similar components. The information currently being determined by the soil surface detection device, and the calculations and conclusions drawn from it in subsequent process steps, may therefore refer to conditions and / or a soil profile that the milling drum of the soil milling machine will only traverse after a time and / or distance delay. For this reason, it is preferred if step g) is sequential to steps b) to f) depending on the time and / or distance traveled.More specifically, it may be intended that, for example, conditions and / or parameters from one or more of steps b) to f) are only taken into account in step g) when the soil milling machine has covered a defined distance during the ongoing milling operation, for example the distance in the milling direction from the milling edge of the milling drum into the unmilled soil surface to the beginning of the detection area along the reference line and / or to one of the reference points.

[0016] The detection area can be designed such that, viewed in the milling direction of the soil milling machine, a segment of the soil surface is captured, thus ensuring that the detection occurs within a defined area whose spatial position relative to the soil milling machine is known. Additionally or alternatively, the detection area can also be designed to run along one or more detection lines parallel to each other and in the direction of travel.In this case, data acquisition is carried out strictly along a reference line, resulting in a more or less two-dimensional soil profile in step c). If several reference lines run parallel to each other, it is possible to simulate the soil areas between the reference lines when creating the digital soil surface profile, for example, by a curved or straight virtual connecting line, interpolation, or similar method perpendicular to the course of the reference lines. In this case, it is possible to simulate the digital soil surface profile as a digital, virtual area based on two or more reference lines.

[0017] In step c), it may be possible to link a large number of reference points, each with individual height information, in the reference datum system aligned with the soil milling machine and use them to create the digital soil surface profile. As mentioned above, this can be done using two or more reference lines or by distributing several reference points across an area of ​​the survey, for example, systematically or randomly.

[0018] It is advantageous if the individual height information is determined as a distance perpendicular to the working direction in relation to the current ground height of at least one of the drive units of the soil milling machine. In this case, a virtual plane is assumed as the reference line or reference plane for determining the individual height information. This virtual plane contains at least one of the drive units, in particular at least one of the rear drive units and / or the drive units running in the milling drum's milling bed. Additionally or alternatively, at least one of the front drive units can also be used as the starting point of a virtual plane, which serves as the reference plane for determining the individual height information. The individual height information can also be determined in relation to one or more reference points, particularly those adjacent to the reference line.In this case, the system calculates the distance between adjacent reference points in the vertical direction. Alternatively, or additionally, it is also possible to determine the individual height information relative to a reference point of the milling machine. If the individual height information is calculated relative to a virtual reference line, it is advantageous if this reference line is at least aligned with the milling direction, i.e., the direction of movement of the milling machine during the milling process. If, on the other hand, the calculation of the individual height information is carried out relative to a reference plane, it is advantageous if the reference plane is defined by the aforementioned reference line and, for example, by the course of the rotation axis of the milling drum perpendicular to it.

[0019] The soil surfaces to be processed by soil milling machines of the present type are often traffic areas, such as roads and / or runways for aircraft. These surfaces are therefore frequently longitudinal and / or marked, such as shoulders and / or lane markings. It is preferred that in step c) the identification of an orientation line extending in the working direction of the soil milling machine, formed by an optically perceptible appearance and / or spatial structure of the soil surface within the detection range, takes place in the digital soil profile. This can be achieved, for example, using suitable image analysis software by identifying linearly extending, essentially homogeneous structures in the digital soil surface profile through color comparisons and / or contrast differences, as might be the case with a road shoulder marking.Additionally or alternatively, the digital ground profile can be examined to identify raised or sunken structures that are constant or constantly changing in height compared to adjacent ground surface areas. Such a structure can also be created by lane markings applied to a road asphalt mat.

[0020] The identification of such an orientation line can be used in various ways when carrying out the method according to the invention. For example, it is possible to virtually place the at least one reference line for carrying out the method according to the invention precisely along the course of the orientation line. This can be advantageous because the coating materials frequently used for road markings allow for comparatively precise, non-contact spatial determination using the surface detection device included in the floor milling machine. Furthermore, such markings often extend into areas of a road surface that are less stressed and therefore exhibit fewer surface irregularities during repairs. The identification of one or more orientation lines can be carried out, in particular, with a control unit running a suitable computer program.

[0021] When identifying the orientation line, it may be provided that any interruptions and / or deviations occurring temporarily in the visually perceptible appearance and / or the spatial formation in an identified orientation line are compensated, preferably virtually, in particular with a control unit with a suitable Computer program. Such interruptions can occur, for example, due to wear-related irregularities in the ground surface or similar factors. Specifically, it may be stipulated that when an interruption occurs in a guideline, it is checked whether the guideline continues after the interruption and / or deviation. The extent to which and / or for how long this check for continuation is carried out can, for example, be limited to a defined distance to be covered.

[0022] The identification of one or more orientation lines can be used, either additionally or alternatively, to determine the course of the soil surface to be milled, for example, the course of a road. This allows, for instance, the curve of the subsoil to be milled to be detected and identified. Based on this, the method can also include a steering control system such that the control unit manages and regulates steering functions in such a way that the soil milling machine automatically follows the path determined by the course of the at least one identified orientation line, thus eliminating the need for manual steering input from an operator.

[0023] The control of the milling depth in step g) depends, among other things, on the determination of the average height of the unmilled subsoil. In steps d) to g), it can be provided that the average height of the digital soil surface profile, the height of the reference line, the local difference level, and the local corrective milling depth are continuously updated during the milling operation. This can be done continuously and / or at intervals, depending on time and / or distance traveled.

[0024] It is advantageous if, in step f), milling is carried out at the level of the respective reference point using the local corrective milling depth. This means that the determination of the local corrective milling depth is dependent on the path length and therefore also occurs with a time delay compared to the application of the corrective milling depth. However, this is not strictly necessary. Immediate implementation can also result in a smoothing of the milled soil surface.

[0025] Soil milling machines of the present type can, in addition to changing the milling depth itself, also allow for a change in the so-called lateral tilt of the soil milling machine relative to the soil surface. The lateral tilt of the soil milling machine refers to the alignment of the soil milling machine in the horizontal direction perpendicular to the milling or working direction, and thus a movement of the soil milling machine around a roll axis running in the longitudinal direction of the soil milling machine. To enable such a change in the relative alignment of the soil milling machine, or at least parts of it, in particular the milling drum, it is known, for example, to adjust the machine frame and thus also The milling drum, mounted on this machine frame, is connected via lifting devices to ground-mounted transport devices, such as wheels or tracks, so that the machine frame and the milling drum can be moved around their axis of rotation relative to the ground by adjusting the lifting devices. This can result in the milling depth of a milling drum, whose axis of rotation is essentially horizontal and perpendicular to the working direction, differing between its two ends and / or requiring individual adjustment.For this purpose, it can be advantageous if steps a) to g) are carried out simultaneously or sequentially for a right and a left side of the soil milling machine using at least one right-side and one left-side reference line, wherein the at least one right-side and the at least one left-side reference line are spaced apart from each other transversely to the working direction along an axis of rotation of the milling drum, in particular in a track of travel of the soil milling machine projected in the working direction. This provides at least one digital soil surface profile for the right side and one digital soil surface profile for the left side of the milling drum. Depending on the design of the detection area, these two digital soil surface profiles can also be part of a complete soil surface profile spanning both the right and left sides of a soil.

[0026] Based on the aforementioned further development of the inventive method, the correction of the target milling depth to a local corrective target milling depth in step g) can be carried out for one side depending on the reference line on that side and independently of the reference line of the other side, or for one side depending on both the reference line on that side and the reference lines on the other side, or for one side independently of the reference line of that side and depending on the reference line of the other side, or for one side depending on the reference line of that side and / or the other side and depending on a quenching value and / or a quenching specification.The lateral displacement can be determined directly using one or more suitable sensor devices or derived indirectly, for example, computationally, in particular by determining the stroke position of a right and a left side plate, or by similar methods known in the prior art. One side can be the right side of the soil milling machine as viewed in the milling direction, and the other side can be the left side of the soil milling machine, or vice versa.

[0027] Another aspect of the invention relates to a soil milling machine, in particular a cold road milling machine. The soil milling machine is specifically designed for carrying out the method according to the invention. Such soil milling machines are regularly used, for example, for the rehabilitation of road surfaces and serve to remove soil to a desired milling depth. A generic A soil milling machine comprises a machine frame, which constitutes the essential supporting structure of the machine; one or more drive motors, which provide the drive energy required for travel and operation, for example, an internal combustion engine and / or an electric motor; and travel devices, such as wheels or tracked drives, driven directly or indirectly by the drive motor, which are at least partially connected to the machine frame via height-adjustable lifting devices. These lifting devices thus make it possible to adjust the distance of the machine frame from the ground. The lifting devices can, for example, be lifting columns of a known design. Finally, for milling the ground, the soil milling machine includes a milling unit comprising a milling drum for milling soil material.The milling drum can, for example, comprise an essentially hollow cylindrical support tube, on the outer surface of which a multitude of milling tools are arranged. During milling operation, the milling drum rotates, for example, around an axis of rotation that runs transversely to the working or milling direction of the soil milling machine and is essentially horizontal.

[0028] Starting with a soil milling machine of the generic type, a soil milling machine according to the invention has at least one soil surface recording device, which is designed for the contactless recording of spatial soil surface data of a soil surface extending in the direction of the working direction of the soil milling machine in front of the soil milling machine and lying within a detection range. The soil surface recording device is thus part of the soil milling machine itself and is carried along by the soil milling machine during ongoing milling and working operations.

[0029] A control unit is also part of a soil milling machine according to the invention, wherein the control unit is designed such that it i) creates a digital soil profile of the recorded soil area with height information for at least two reference points based on the spatial soil surface data obtained from the soil surface recording device. These reference points are spaced apart from each other on a common reference line extending parallel in the direction of work and are located at a defined distance from the soil milling machine in the direction of work in front of the milling drum, ii) determines an average height of the digital soil surface profile by including the height information of the at least two reference points and defines this average height as the height of the reference line, iii) determines a local difference distance of the at least two reference points to the height of the reference line.iv) corrects a specified target milling depth to a local corrective target milling depth depending on the current position of the milling drum in the working direction of the soil milling machine and depending on the respective local differential distance, and v) during milling, controls one or more of the height-adjustable lifting devices in such a way that the subsoil is milled to the local corrective target milling depth. For this purpose, the control unit is connected via at least one wired, or a wireless information and / or data transmission connection in conjunction with the soil surface recording device. The spatial soil surface data determined by the soil surface recording device are transmitted to the control unit via this information and / or data transmission connection, for example, a bus system of the soil milling machine. The control unit itself can be a computer system comprising one or more computer programs suitable and configured to perform the aforementioned steps of the control unit. This could be, for example, a program for image data processing and / or evaluation, a simulation program, or similar software. Regarding the execution of the measures to be carried out by the soil surface recording device and the control unit, in particular also according to steps i) to v), reference is made to the preceding descriptions of the method according to the invention.Because the ground surface recording device ultimately carries the reference system used to determine the average height along with the ground milling machine, it is unnecessary to measure the ground surface prior to the actual milling process using an external device and / or by using an external reference source, such as a local total station, and yet still achieve a smoothing of transverse waves.

[0030] Regarding the specific design of the ground surface imaging device, several preferred approaches exist. For example, the ground surface imaging device could be a 3D camera, in particular a digital stereo camera, a TOF camera, especially with a PMD sensor, and / or a laser scanner, in particular a LiDAR scanner. It is also possible to combine different ground surface imaging devices based on different operating principles.

[0031] The control unit is preferably designed to compare and combine spatial ground surface data from multiple ground surface recording devices. This can include, for example, combining ground surface data or information relating to the same ground area, such as when the same ground area is recorded, particularly simultaneously or at least with temporal overlap, by multiple ground surface recording devices that have different operating principles, for example, the combination of a TOF camera with a laser scanner. Additionally or alternatively, spatial ground surface data from multiple devices that only partially overlap or are at least directly adjacent to each other with respect to their respective recording areas can be combined. Soil surface sampling devices can also be assembled ("stiching").

[0032] It is advantageous if the control unit includes a rolling data storage unit for storing spatial ground surface data and / or the digital ground profile and is designed such that the digital ground profile is updated depending on time and / or the distance traveled by the milling machine. For this purpose, it can be provided that the most recent spatial ground surface data and / or digital ground profiles, in terms of time and / or distance traveled, replace previous spatial ground surface data and / or digital ground profiles.

[0033] There are various possibilities regarding the specific arrangement of one or more soil surface detection devices on the rest of the soil milling machine. Since it is particularly important in this case to design the detection range of the soil surface detection device(s) in such a way that at least part of a soil surface lying in front of the soil milling machine in the working direction, and thus still unmilled in the current milling pass, is to be detected, it is advantageous to position the soil surface detection device on the rest of the soil milling machine in such a way that it has at least a partially unobstructed view of the soil area lying in front of the soil milling machine in the working direction.For this purpose, the soil surface recording device can be arranged, for example, on the front of the soil milling machine, on a conveyor belt projecting forward in the working direction, on and / or on the roof of a control station and / or a driver's cab and / or on a special storage device, wherein the storage device is sensibly designed in such a way that the position of the soil surface recording device is spaced away from the rest of the soil milling machine in order to allow a clear view of the desired area of ​​the soil surface, especially during milling and loading operations.

[0034] Elements projecting from the main body of the soil milling machine, such as the aforementioned bearing assembly for the soil surface sampling device, are often perceived as disadvantageous in practical use. To nevertheless allow the soil surface sampling device to be positioned, at least partially, exposed to the main body of the soil milling machine, it can be provided that the soil surface sampling device is connected to the rest of the soil milling machine via an adjustment device. This device is designed such that the relative position of the soil surface sampling device is adjustable in the vertical and / or horizontal direction, particularly transversely to a working direction of the soil milling machine, relative to the rest of the soil milling machine, and especially relative to at least the milling drum.For example, the adjustment device can be designed in such a way that it allows for a displacement and / or pivoting and / or telescoping of the ground surface recording device. The adjustment mechanism allows for movement between at least two end positions compared to the rest of the tilling machine, for example, at least one detection position projecting from the rest of the tilling machine and a compact storage position. Furthermore, or alternatively, the adjustment mechanism can be designed such that the adjustment is manual and / or motor-driven by at least one drive. The adjustment mechanism can also be designed such that the soil surface detection device can be selectively adjusted to the right or left side of the tilling machine.

[0035] For the reasons mentioned above, it is therefore important that the soil surface recording device has at least a partial unobstructed view of the soil surface still to be milled in the working direction of the soil milling machine. However, particularly for soil milling machines where the milled material is loaded forward in the working direction, such as so-called front loader milling machines, the transport vehicle, for example a truck, often also moves in this area. It is therefore preferable if, in this operating situation, the transport vehicle is positioned laterally offset relative to the soil milling machine in the working direction, thus obscuring as little of the soil surface in the current milling path of the soil milling machine as possible.To assist the driver of the transport vehicle in aligning their vehicle with the soil tiller, the soil tiller may be equipped with a signaling device. This device allows the driver of a transport vehicle traveling in front of the soil tiller to check for a defined lateral offset of the transport vehicle in the horizontal direction and perpendicular to the working direction of the soil tiller relative to the soil tiller. For example, the soil tiller may have a suitable marking for this purpose, which a driver in the transport vehicle can see, for example, through a side mirror and use to align their vehicle.Additionally or alternatively, the signaling device of the soil milling machine can also include a display device that indicates to the driver of the transport vehicle whether the current relative position of the transport vehicle is correct or requires correction. For this purpose, the control unit can, for example, determine via image data analysis whether the transport vehicle is currently within the detection range and, if so, display or at least signal this accordingly via the display device.In addition or alternatively, the soil milling machine may also have a projection device, for example a laser pointer or similar, which projects a signal visible to the driver of the transport vehicle onto the ground surface, for example the outer edges of the detection area and / or at least one point by which the driver of the transport vehicle can orient himself to align his vehicle relative to the soil milling machine.

[0036] According to a further preferred embodiment, the soil milling machine finally comprises a display device, for example a display, which is designed for the pictorial reproduction of the image taken by the soil surface recording device, in particular modified as a two-dimensional image, and / or the soil profile, wherein the control unit is designed such that at least one additional piece of information is virtually projected or superimposed onto the displayed pictorial reproduction.The additional information may include, in particular, one or more edges of the detection area, the location and / or course of at least one reference line and / or at least one detection line, the location of at least two reference points, one or more pieces of information on the differential distance and / or the local correction target milling depth, the location and / or course of at least one identified orientation line, in particular with information on the geometry of the orientation line, for example, whether it consists of curved and / or straight sections, identified obstacles and / or anomalies in the ground surface, for example, interruptions in an orientation line, areas bridged by interpolation and / or extrapolation of an orientation line, etc.

[0037] The invention is explained in more detail below with reference to the exemplary embodiments shown in the figures. The figures schematically depict: Fig. 1 shows a side view of a soil milling machine in a work train with a transport vehicle; Fig. 2 shows a perspective view of an exemplary chassis of a soil milling machine with lifting devices; Fig. 3 shows a side view of a soil milling machine during contactless spatial scanning of a soil surface; Fig. 4 shows a top view of a work train with a soil milling machine and a transport vehicle; Fig. 5 shows a top view of an alternative work train with a soil milling machine and a transport vehicle; Fig. 6 shows a top view of another alternative work train with a soil milling machine and a transport vehicle; Fig. 7 shows a schematic view of a control unit for carrying out a method according to the invention; Fig. 8 shows a flowchart of a method according to the invention; the display from Fig. 7 Fig. 9 shows a two-dimensional display of a ground surface recorded by a ground surface imaging device; Fig. 10 shows the display from Fig. 7 with additional information displayed; Fig. 11 shows a ground surface profile created from the spatially captured ground surface underlying the display in Fig. 9; Fig. 12 shows the ground profile depicted in Fig. 11 with a distance-dependent update; Fig. 13 shows an interpolation of two current soil profiles; Fig. My alternative two-dimensional display of a ground surface image captured by a ground surface imaging device; Fig. 15 shows the display from Fig. 14 with additional information displayed; Fig. 16 shows a first ground surface profile created from the spatially captured ground surface underlying the display in Fig. 15 along a first reference line; Fig. 17 a second ground surface profile created from the spatially captured ground surface underlying the display in Fig. 15 along a second reference line; Fig. 18 shows a third ground surface profile created from the spatially captured ground surface underlying the display in Fig. 15, along a third reference line; Fig. 19 is a summary of the soil profiles shown in Figures 16 to 17; Fig. 20 shows a two-dimensional display of a ground surface recorded by a ground surface imaging device; and Fig. 21 shows the display from Fig. 20 with additional information displayed.

[0038] Identical components and / or components with the same function may be identified by the same reference symbol in the figures. Elements that are repeated in the figures are not necessarily labeled in every figure.

[0039] Figure 1 shows an exemplary soil milling machine 1. This machine comprises a machine frame 3 supported by drive units 2, a drive motor 4, and a milling unit 5. The drive units 2, which rest on the ground surface 16 and can be, for example, wheels or tracks, are connected to the machine frame 3 via lifting devices 6. The drive motor 4 can provide the drive energy required for travel and operation, making the soil milling machine 1 self-propelled. Although it is possible to move the milling unit itself To design the milling unit 5 to be height-adjustable relative to the machine frame 3, it is preferred if the milling unit 5, together with the machine frame 3, is adjusted by one or more of the lifting devices 6 relative to the ground surface 7 to change the milling depth FT, and the milling unit is thus arranged as a fixed assembly, for example, on the machine frame 3. The milling unit 5 can comprise a milling drum housing, one or more side plates, a scraper, a hold-down device, etc., as well as a milling drum 8. The soil milling machine 1 can include a transport device 9, for example, comprising a bulk material conveyor belt projecting from the machine frame 3, for transporting the milled material, for example, into a transport trough of a suitable transport vehicle 10 (only partially shown in Fig. 1). During milling operation, the soil milling machine moves in working or...Milling direction A, the milling drum 8, which plunges into the subsoil, mills soil material in the form of milled material and can transport and load this milled material away from the milling unit 5 in a manner known per se via a transport device 9.

[0040] The soil milling machine 1 may also include a display device 11, which may be arranged, for example, within a control station 12 from which the soil milling machine 1 can preferably be operated, at least partially. The soil milling machine may also include a signaling device 13, the function and possible design of which will be explained in more detail below.

[0041] The soil milling machine 1 comprises a control unit 14 and one or more soil surface detection devices 15. These are interconnected via one or more data and / or information transmission links 17, for example wirelessly or wired, in particular such that data and / or information about the soil surface spatially detected by the soil surface detection devices 15 is transmitted to the control unit 14. For clarity, only one of the information transmission links 17 is shown in Fig. 1.

[0042] Figure 2 illustrates details of the possible construction of the chassis of the soil milling machine 1. Details beyond the machine frame 3 are omitted in Figure 2 for clarity, except for the chassis elements relevant to adjusting the machine frame 2 relative to the ground surface 16. In the embodiment shown in Figure 2, the machine frame 3 is supported by a total of four lifting devices 6vl, 6vr, 6hl, and 6hr, each connecting one of the drive units 2 resting on the ground surface 16 to the machine frame 3. Each of the lifting devices 6vl, 6vr, 6hl, and 6hr can be adjusted in height, so that the machine frame 3 as a whole can be adjusted in height, or, for example, rolled / tilted about a longitudinal axis L and / or inclined about a transverse axis Q running parallel to the axis of rotation R of the milling drum 8. Inclined positions are also possible.The relative position of the rotation axis R of the milling drum 8 is. The milling drum 8 is fixed in position relative to the machine frame 3. If the height of the machine frame 3 is thus changed, at least partially, by adjusting the stroke of one or more of the lifting devices 6, the milling drum 8 can, for example, be lowered from a raised position to a position resting on the unmilled soil surface 16, or lowered into the subsoil to a desired milling depth. It is understood that for these processes, one or more sensors can be included in the soil milling machine 1, which, in a manner known per se in the prior art, determine, for example, the milling depth FT of the milling drum and / or the stroke position of one or all lifting devices 6 and / or the machine frame 3 relative to the soil surface and / or the position of the machine frame and / or the milling drum about one or both of the axes Q and L, and transmit this information, for example, to the control unit 14.Additionally or alternatively, the control unit 14 can directly or indirectly control and / or regulate the stroke adjustment of one or more of the lifting devices 6, for example to set and / or maintain a desired milling depth.

[0043] Fig. 3 shows a soil milling machine 1 with a transport device 9 projecting from the rear of the machine and thus towards the rear in the working direction A. The soil surface detection device 15 of the soil milling machine 1 is oriented with its detection range 18 towards the working direction A and detects the soil surface 16 located within the detection range 18 without contact. This surface surface contains large transverse ripples. The milling bed 19 is located behind the milling drum 8, which engages the subsoil, in the working direction A. The target path 19' of the milling bed is indicated by a dashed line. Fig. 3 illustrates that, due to the existing transverse ripples, the local milling depths required to maintain the target path 19' of the milling bed 19 vary.Using the soil surface recording devices 15, the soil milling machine 1 itself acquires three-dimensional information on the position and course of the soil surface 16 in the recording area 18 from its own reference point 20, which forms the zero point of a spatial coordinate system with the axes x, y and z. It is understood that the actual position of the zero point from the soil milling machine 1 can be varied according to specific conditions and design requirements.

[0044] Fig. 4 illustrates this process in a top view for an alternative working unit. In this example, the soil milling machine 1 comprises several soil surface detection devices 15, specifically 15a, 15b, and 15c. These are arranged on the soil milling machine 1 such that their individual detection areas 18a, 18b, and 18c partially overlap. The areas of the soil surface 16 spatially detected by the soil surface detection devices 15a, 15b, and 15c can be combined by the control unit 14 into a continuous, spatially detected soil surface 16 by means of a suitable computer program.

[0045] In the operating situation shown in Fig. 4, the truck 10 driving in front of the soil milling machine 1 is offset laterally, specifically to the left, with respect to the longitudinal center axis of the soil milling machine 1 when viewed in the working direction A. This allows the soil surface detection device 15a of the soil milling machine to see at least a significant portion of the soil area 16 in front of it in the working direction A, i.e., the subsoil still to be milled when projecting the current travel path of the soil milling machine 1. To provide the driver of the truck 10 with orientation regarding this desired lateral offset of his vehicle relative to the following soil milling machine 1, the soil milling machine 1 includes the signaling device 13, which can, for example, be a projection device that projects a spot of light 21 onto the soil surface 16, which can be seen by the truck driver and used as an orientation aid.

[0046] Fig. 4 further illustrates that the soil surface recording devices 15 can be arranged not only to exclusively record a soil area located in the working direction A in front of the soil milling machine 1, but also, or alternatively, to record an area 18b that is additionally offset laterally and horizontally to the working direction A and / or an area 18c located next to and at the level of the soil milling machine 1 when viewed in the working direction a. This increases the range of soil profiles that the operator of the soil milling machine 1 can use to control the milling depth in the manner described in more detail below.

[0047] Figures 5 and 6 illustrate further arrangement alternatives of several of the soil surface recording devices 15 on a soil milling machine 1.

[0048] In the embodiment shown in Fig. 5, two soil surface detection devices 15a and 15b are arranged at the same height in the working direction A. It is possible to switch from one soil surface detection device 15a to the other soil surface detection device 15b, for example depending on the relative positioning of a transport vehicle moving in front of the soil milling machine 1, and vice versa.

[0049] In the embodiment shown in Fig. 6, one of the soil surface receiving devices 15a is arranged on the part of the transport device 9, for example a trailing conveyor belt, which projects forward from the soil milling machine 1 in the working direction a. Furthermore, the soil milling machine 1 comprises two soil surface receiving devices 15b and 15c, each adjustable with respect to its relative position between at least two end positions by means of an adjustment device 22. The adjustment device 22 makes it possible to position the respective soil surface receiving devices 15b or 15c between a position relative to the main body, which is formed in particular by the machine frame 3. The soil milling machine 1 can be adjusted between its exposed detection position and a space-saving storage position relative to this main body, which is shown with a dotted line in Fig. 6. This allows for an optimal relative position of the respective soil surface detection devices and the rest of the soil milling machine 1, depending on the application and / or operating conditions. For this purpose, the adjustment device 22 can be provided to allow the respective soil surface detection devices 15 to be shifted and / or pivoted relative to the rest of the soil milling machine 1.

[0050] Fig. 7 schematically illustrates the integration of the control unit 14 into the soil milling machine 1, particularly for carrying out a method according to the invention. The control unit 14 receives data and / or signals via the data and / or information transmission link 17 relating to the soil surface spatially detected by the soil surface detection device 15, specifically information on the distance (x, y, z) between at least two detected reference points on the soil surface with respect to a reference point or zero point 20 that is fixed relative to the soil milling machine 1. For this purpose, the soil surface detection device 15 can, for example, comprise a TOF camera 15' and / or a LIDAR 15".

[0051] Furthermore, the control unit 14 can receive sensor data from a sensor device 23, which, for example, records operating and / or position parameters of the soil milling machine 1 and / or one or more of its elements. The sensor device 23 can, for example, include one or more stroke sensors 23.1 that record the stroke position of one or more of the lifting devices. A position sensor 23.2, for example, a GPS receiver, can also be included in the sensor device 23 to determine and track the position of the soil milling machine 1 in a higher-level coordinate system. A distance sensor 23.3, designed to determine the distance traveled by the soil milling machine 1 per unit of time, can also be part of the sensor device 23. One or more milling depth sensors 23 can be used to determine and monitor the milling depth.4 includes, for example, so-called side shield sensors, contactless ground clearance sensors, etc. Finally, the sensor device 23 can also, for example, have one or more longitudinal and / or lateral tilt sensors 23.5 in order to detect a longitudinal and / or lateral tilt of the soil milling machine.

[0052] Furthermore, an input device 24, for example in the form of a manually operated control element, such as a keyboard and / or a touch-sensitive input display, may be provided, via which operating specifications, such as a target milling depth SFT, can be transmitted to the control unit 14.

[0053] The control unit 14 can communicate with a display and / or documentation device 25, which may include, for example, the display device 11, a printer 11', a data storage device and the like.

[0054] Furthermore, the control unit may include a communication device 26 and / or be in a transmission connection with it, via which, preferably wirelessly, data and / or signals can be transmitted from the control unit 14 to a transmitting and receiving device outside the soil milling machine 1, such as a remote server, one or more other machines, a mobile device such as a smartphone, etc.

[0055] Based on the received information, the control unit 14 can generate a digital soil surface profile and transmit control commands to relevant devices of the soil milling machine 1 for controlling and / or regulating the current milling depth FT, such as motors and / or actuators and / or valves and / or other drive and / or switching devices by which the current milling depth of the soil milling machine 1 can be changed. These could include, for example, the lifting devices 6 and / or an adjustment device 27 by which the relative position of the milling drum with respect to the machine frame 3 can be changed.

[0056] The control unit 14 comprises a computer program suitable for creating the digital soil profile based on the spatial structure of the soil surface data acquired by the soil surface recording device(s) 15. This program may be suitable for image processing. The control unit 14 may also have a rolling data storage device 28, which is designed such that older data relating to the acquired soil profile are continuously replaced by newer data relating to the acquired soil profile during milling operation and are thus updated with respect to the changing relative position of the soil milling machine 1 to the subsoil.

[0057] Fig. 8 shows a flowchart of essential steps of an example of a method according to the invention.

[0058] In step a), the target milling depth is first determined. This can be done, for example, by a manual setting by an operator or similar method. Additionally, the zero position of the milling drum can be determined by lowering it from a position raised above the ground to the surface without milling any soil material. As soon as the milling drum makes contact with the unmilled soil surface, the zero position can be defined, so that any lowering beyond this zero position then indicates the actual milling depth.

[0059] In step b), a soil surface extending in front of the soil milling machine in the direction of its work and lying within a detection range is detected contactlessly using a soil surface detection device 15, as already described for example in the preceding figures. Figure 9 shows an example of a two-dimensional projection of a soil surface detected by a soil surface detection device, as could, for example, be displayed to the operator of the soil milling machine 1 via the display device 11. In the present example, a road 28 extending in the direction of work A in front of the soil milling machine 1 is visible, with a left shoulder 29L, a median strip 29M, and a right shoulder 29R.It is understood that the survey of the ground surface is preferably carried out over an entire area. However, it is also possible that this is only possible along one or more survey lines extending in the direction of work. The survey line then runs along the reference line.

[0060] In step c), a digital soil surface profile of the surveyed soil area is created, containing elevation information for at least two reference points. These reference points are located on a common reference line that extends parallel to the direction of travel and are spaced apart from each other. Each reference point lies at a defined distance from the soil milling machine in the direction of travel, in front of the milling drum. This is illustrated in more detail in Fig. 10. There, the virtual reference line RI is shown, extending parallel to the current direction of travel of the soil milling machine 1. In this example, reference points RI to R6 are all located on this line.Each of these reference points RP1 to RP6 is spatially linked by the soil surface recording device 15 with position coordinates x, y, and z in relation to a reference point on the soil milling machine 1 (such as the aforementioned zero point 20), and thus each has, for example, a specific distance value Al to A6. It is understood that the number of reference points can be significantly increased, and for the sake of clarity, only six reference points RP are specified here.

[0061] Based on the available spatial coordinates of the respective reference points RP1 to RP6 relative to the soil milling machine 1, the control unit 14 creates a digital soil profile 30, for example using a suitable computer program, as shown in Fig. 11 for the z-position of the reference line RI. The digital soil profile shows the presence of several large transverse waves, with wave troughs W1 and W2 and wave crest W3. The target milling depth is indicated by SF. If the target milling depth were kept constant when milling over the reproduced soil profile 30, the wave structures W1 to W3 would be traced identically and copied into the resulting milling bed. However, in this case, it is intended that the control unit adapts these wave structures to a local correction target milling depth kSFT by adjusting the target milling depth.

[0062] In step d), an average height 31 of the digital ground surface profile is determined, taking into account the height information of the available spatial information of the respective reference point P. This can be done, for example, by calculating an arithmetic midpoint of the available height information for the respective reference points.

[0063] The average height 31 calculated by the control unit 14 is assumed in step e) to be the height of the reference line R, so that, based on this, it is possible in step f) to assign a local differential distance AH1 to AH6 to each of the considered reference points relative to the height of the reference line 30. In the embodiment according to Fig. 6, AHI, AH3 and AH6 are, for example, practically zero. The digital ground profile lies at the height of the average height 31. AH2 and AH5 lie below the average height by a determinable amount in the vertical direction y, and AH4 lies above it.

[0064] In the subsequent step g), the subsoil is milled in the working direction. The soil milling machine moves in direction x in Fig. 11. The control unit then corrects the target milling depth SF to the local correction target milling depth kSF when it reaches the further reference points RP, depending on the current position of the milling drum in the working direction of the soil milling machine and depending on the respective local differential distance to compensate for the respective difference. Specifically, the target milling depth SF would thus be corrected to kSF2 at A2, to kSF4 at A4, and to kSF5 at A5. The respective correction target milling depth kSF results from the target milling depth SF plus (in the case that the digital soil profile is above the average height) or minus (in the case that the digital soil profile is below the average height) the respective local differential distance AH.

[0065] Fig. 12 shows a digital soil profile 30 created by the control unit 14, which was generated based on the digital soil profile 30 shown in Fig. 11. The soil milling machine has thus already covered a defined distance during milling operation, determined, for example, by means of a distance sensor. The remainder of the original digital soil profile from Fig. 11 is labeled 30' in Fig. 12. Based on the reference points originally used to determine the average height 31, it is evident that the current average height 31 is determined differently compared to the previous average height 31' from Fig. 11. In this case, it is possible that the control unit 14 also adjusts the individual correction target milling depths kSF during the ongoing milling operation. As a result, existing large transverse waves are smoothed or reduced in amplitude.

[0066] Fig. 13 illustrates a further variant for carrying out the method. In this further development, steps a) to g) are carried out simultaneously or sequentially for a right and a left side of the soil milling machine 1 by means of at least one right-side and one left-side reference line, wherein the at least one right-side and the at least one left-side reference line are spaced apart from each other transversely to the working direction along an axis of rotation of the milling drum, in particular in a working direction away from the projected travel path of the soil milling machine. Both reference lines provide an individual digital soil profile 30A and 30B, each with an individual average height 31A and 31B.The steps of the procedure described above, in particular step g) for correcting the target milling depth, can now be carried out separately for both sides, taking into account the digital soil profile 30A with average height 31A and the digital soil profile 30B with average height 31B, for example, by adjusting the height of a left-hand lifting device for 30A and 31A and a right-hand lifting device for 30B and 31B. Alternatively, the milling depth can also be determined taking into account an average height 3IC, which, for example, is applied vertically with an equal distance in magnitude between the average heights 31A and 31B. This correction mode can also result in a reduction of existing transverse waves, especially those running obliquely to the working direction A.

[0067] To further illustrate another alternative, reference is first made to Fig. 14, which is a representation of another road section comparable to Fig. 9. In the road shown, there is a pothole 32 and a transverse wave 33 sloping to the right. This is recognizable by the optical kink in the course of the right shoulder 29R. The left shoulder 29L, on the other hand, runs on a substantially flat surface and extends accordingly in a straight line into the viewing perspective.

[0068] Fig. 15 shows a representation comparable to Fig. 10, in which, in this case, a total of three reference lines RI, R2, and R3 are displayed, each with five reference points (not specified for clarity) marked as circles. Fig. 16 shows the digital ground surface profile 30 generated by the control unit 14 for reference line RI, Fig. 17 shows the digital ground surface profile 30 generated by the control unit 14 for reference line R2, and Fig. 18 shows the digital ground surface profile 30 generated by the control unit 14 for reference line R3. Fig. 15 also shows the milling width FB of the milling drum 8 and the lateral distance D, which is currently given perpendicular to the working direction A in the horizontal plane relative to reference line RI. Fig. 19 shows the three digital ground surface profiles 30 superimposed.Figure 19 illustrates that the soil profiles 30 differ from each other. It may now be provided that the control unit is selected from the available ones. The reference line is determined to be the one that exhibits the smallest deviations, particularly in terms of magnitude, from the respective average height across the detection area in working direction A, and only this single reference line is used to correct the target milling depth in the manner described above. For example, it may additionally be provided that the milling depth is controlled in such a way that a given cross slope of the soil milling machine, determined, for example, by a cross slope sensor, is maintained during milling operation. In this operating mode, the pothole 32 and the transverse wave 33 are completely eliminated or leveled, leaving no trace of the soil surface structure in the milled bed.

[0069] Figures 20 and 21 illustrate curve detection, which can also be used, for example, to define reference lines for carrying out the aforementioned process steps. Similar to Figures 9 and 14, Figure 20 initially shows a two-dimensional projection of a ground surface spatially captured by the ground surface detection device within a detection range. Based on the available information, including, for example, two-dimensional image information, the control unit 14 can first identify structures extending linearly in the working direction. This is indicated in Figure 21, for example, by areas 34L and 34R, which comprise straight sections of the side strips 29R and 29L.Furthermore, the control unit 14 identifies two curved sections 35L and 35R, to which two further straight sections 34L' and 34R' are connected in the working direction A. It is now possible for the control unit 14, after identifying a straight section 34, for example, section 34L, to take the reference points to be considered for carrying out the process exclusively from the respective straight section 34, in this case 34L, as shown in Fig. 21 with the circularly marked reference points. Reference points lying outside this section, such as the reference points marked as squares in Fig. 21, are not considered for controlling step g).

[0070] It can be provided that the control unit displays some and / or all of the information shown in the figures, for example, the results of the control unit 14, in the respective display on a display device 11 and virtually overlays it onto the displayed two-dimensional projection, as shown, for example, in Figures 9, 14, and 20. This allows the operator, for example, to select in real time from which identified reference lines, in which combination, from which structures, etc., he wishes to control the milling depth according to step g). For example, in the embodiment shown in Fig. 21, he can select whether step g) should be performed taking 34L and / or 34R into account.

[0071] The identified straight areas 34 and / or curved areas 35 can also be used to steer the soil milling machine. For example, the control unit 14 can use the available spatial information to utilize one or more of these areas to guide the soil milling machine along this area at a constant distance horizontally and transversely to the working direction A with respect to its zero point 20, and determine suitable steering commands and transmit them to a steering device, such as a steering actuator.

[0072] In particular, the straight sections 34 can also be used as a guideline, as locating a reference line there is especially useful. It is therefore preferable if straight lines extending in the direction of work, especially parallel to these sections, are used as reference lines.

[0073] Additional information can also be displayed, such as a current extrapolated track 36 of the soil milling machine or similar.

Claims

PATENT CLAIMS 1. Method for controlling the milling depth of a ground milling machine (1) with a machine frame (3) carried by travel devices (2) and a milling drum (8) which is vertically adjustable in height relative to a ground substratum (7), comprising the steps of: a) setting a target milling depth (SF); b) starting from the ground milling machine (1), contactless spatial detection of a ground surface (16) extending in the direction of work direction (A) of the ground milling machine (1) in front of the ground milling machine (1) and lying within a detection area (18) by means of a ground surface detection device (15); c) creating a digital soil surface profile (30) of the recorded soil surface (16) with height information for at least two reference points (RP) in the digital soil surface profile (30), which are spaced apart from one another on a common reference line (R) extending parallel in the working direction (A) and are each located at a defined distance from the soil milling machine (1) in the working direction (A) in front of the milling drum (8); d) determining an average height (31) of the digital soil surface profile taking into account the height information of the at least two reference points; e) assuming the average height (31) as the height of the reference line (R); f) determining a respective local difference distance (AH) of the at least two reference points (RP) to the height of the reference line (R);g) Milling the subsoil in the working direction (A) and thereby correcting the target milling depth (SFT) to a local correction target milling depth (kSFT) depending on the current position of the milling drum (8) in the working direction (A) of the soil milling machine (1) and depending on the respective local difference distance (AH) to compensate for the respective local difference distance (AH).; 2. Method according to claim 1, characterized in that the detection in step b) within the detection area (18) - along one or more detection lines running parallel to each other and in the direction of the working direction (A) and / or - takes place within a defined area.

3. Method according to one of the preceding claims, characterized in that in step c) a plurality of reference points (RP) are linked to individual height information and used to create the digital ground surface profile (30).

4. Method according to claim 3, characterized in that the individual height information is determined as a distance indication perpendicular to the working direction (A) - in relation to a current contact height of at least one of the driving devices (2) of the ground milling machine (1) or - in relation to one or more reference points (RP), in particular adjacent ones along the reference line (R), or - in relation to a reference point (20) of the floor milling machine (1).

5. Method according to one of the preceding claims, characterized in that in step c) in the digital soil profile the identification of an orientation line extending in the working direction (A) of the soil milling machine (1) and formed by an optically perceptible appearance and / or spatial formation of the soil surface lying in the detection area takes place.

6. Method according to claim 5, characterized in that the at least one reference line (R) is placed in the course of the orientation line.

7. Method according to one of claims 5 or 6, characterized in that temporarily occurring interruptions and / or deviations in the optically perceptible appearance and / or the spatial formation of an identified orientation line are virtually compensated.

8. Method according to one of claims 5 to 7, characterized in that the orientation line is used to determine a curve in the detection area.

9. Method according to one of the preceding claims, characterized in that in steps d) to g) the average height (31) of the digital ground surface profile, the height of the reference line (R), the local difference distance and the local correction target milling depth (kSFT) are continuously updated during the ongoing milling operation.

10. Method according to one of the preceding claims, characterized in that in step f) the milling is carried out with the local correction target milling depth (SFT) at the level of the respective reference point.

11. Method according to one of the preceding claims, characterized in that steps a) to g) are carried out simultaneously or with a time delay for a right-hand and a left-hand side of the ground milling machine (1) by means of at least one right-hand and one left-hand reference line (R), wherein the at least one right-hand and the at least one left-hand reference line (R) run at a distance from one another transversely to the working direction (A) along an axis of rotation of the milling drum, in particular in a track of the ground milling machine (1) projected forward in the working direction (A).

12. Method according to claim 11, characterized in that the correction of the target milling depth (SFT) to a local correction target milling depth (kSFT) in step g) - for one side depending on the reference line (R) on that side and independently of the reference line (R) of the other side or - for one side depending on both the reference line (R) on that side and the reference line (R)n on the other side or - for one side, independently of the reference line (R) of that side and depending on the reference line (R) of the other side, or - for one side, depending on the reference line (R) of that side and / or the other side and depending on a cross slope value and / or a cross slope specification.

13. Soil milling machine (1), in particular a cold road milling machine, comprising a machine frame (3), a drive motor (4), driving devices (2) driven by the drive motor (4), which are at least partially connected to the machine frame (3) via height-adjustable lifting devices (6), and a milling unit (5) with a milling drum (8) for milling soil material, characterized in that it - at least one ground surface recording device (15) for the contactless recording of spatial ground surface data of a ground surface extending in the direction of the working direction (A) of the ground milling machine (1) in front of the ground milling machine (1) and lying within a detection range, and - a control unit (14), wherein the control unit (14) is designed such that it i) creates a digital soil profile of the detected soil area with height information for at least two reference points based on the spatial soil surface data obtained from the soil surface recording device (15), which are spaced apart from one another on a common reference line (R) extending parallel in the direction of work (A) and are each located at a defined distance from the soil milling machine (1) in front of the milling drum (8) in the direction of work (A), ii) determines an average height (31) of the digital soil surface profile taking into account the height information of the at least two reference points and defines this average height (31) as the height of the reference line (R), iii) determines a local difference distance of the at least two reference points from the height of the reference line (R),iv) corrects a specified target milling depth (SFT) to a local correction target milling depth depending on the current position of the milling drum in the working direction (A) of the soil milling machine (1) and depending on the respective local difference distance, and v) during milling, controls one or more of the height-adjustable lifting devices (6) such that milling of the subsoil occurs with the local correction target milling depth (kSFT).

14. Soil milling machine (1) according to claim 13, characterized in that the soil surface receiving device (15) has at least - a 3D camera, in particular a digital stereo camera, a TOF camera (in particular PMD), and / or - a laser scanner, in particular a LIDAR scanner.

15. Soil milling machine (1) according to one of claims 13 or 14, characterized in that the control unit (14) is designed such that it compares and combines spatial ground surface data from a plurality of ground surface recording devices (15).

16. Soil milling machine (1) according to one of claims 13 to 15, characterized in that the control unit (14) comprises a rolling data memory (28) for storing spatial ground surface data and / or the digital ground profile and is designed such that the digital ground profile is updated as a function of time and / or the milling distance traveled.

17. Soil milling machine (1) according to one of claims 13 to 16, characterized in that the soil surface receiving device (15) is connected to the rest of the soil milling machine (1) via an adjusting device (27) which is designed such that the relative position of the soil surface receiving device (15) is adjustable in the vertical direction and / or in the horizontal direction, in particular transversely to a working direction (A) of the soil milling machine (1).

18. Soil milling machine (1) according to one of claims 13 to 17, characterized in that it has a signaling device (13) which is designed such that a driver of a transport vehicle (10) traveling in front of the soil milling machine (1) can check a defined lateral offset of the transport vehicle (10) in the horizontal direction and transversely to a working direction (A) of the soil milling machine (1) relative to the soil milling machine (1).

9. Soil milling machine (1) according to one of claims 13 to 18, characterized in that it comprises a display device (11) which is designed to display the image and / or soil profile recorded by the soil surface recording device (15), wherein the control unit (14) is designed such that at least one of the following additional information is virtually projected into the displayed image: - the detection range; - position and / or course of at least one reference line (R) and / or at least one detection line; - Location of at least two reference points; - Information on the differential distance and / or the local correction target milling depth; - Position and / or course of at least one identified orientation line, in particular with information on the geometry of the orientation line; - identified obstacles and / or anomalies in the ground surface.

Images