Construction machine

Abstract

A construction machine uses a controller configured to determine a cross-sectional profile of a design surface at a selected position and orientation of a milling drum of the construction machine. The controller automatically determines a preferred subset of sensors from a plurality of possible subsets of sensors selected from a set of available sensors. A preferred subset of sensors must be available to create at least a portion of the cross-sectional profile of the design surface. The controller automatically maintains or switches control of the milling depth to use the preferred subset of sensors.

Description

Technical Field

[0001] The present application relates to a construction machine, such as a road milling machine, having a work implement for working a ground surface. Background Art

[0002] A grade control system for a road milling machine is disclosed in US Pat. No. 8,308,395. The system allows an operator of the milling machine to select a desired sensor from the available sensors and manually direct a change of the operable sensors from one subset of sensors to another subset of sensors.

[0003] It is also known from US patent publication No. 2002 / 0154948 to automatically switch between two available sensors on a construction machine when an operable one of the sensors becomes inoperable.

[0004] There is a continuing need for improved grade control systems in order to provide further functionality for construction machines, in particular for milling machines. Utility Model Content

[0005] In a first embodiment, a method of controlling a construction machine is provided, the construction machine comprising: a machine frame having a longitudinal frame axis extending between a front end and a rear end of the machine frame; a milling drum supported by the machine frame and having a milling drum rotation axis perpendicular to the longitudinal frame axis; and a controller configured to control a milling depth of the milling drum as the construction machine moves across a ground surface, the method comprising the following steps:

[0006] (a) providing a design surface data set to the controller, the design surface data set defining a design surface to be created in a reference frame external to the construction machine;

[0007] (b) providing to the controller a prioritization of a plurality of possible subsets of sensors selected from a set of available sensors;

[0008] (c) performing a milling operation with the milling drum as the construction machine moves across the ground surface;

[0009] (d) determining, with the controller, data representing a cross-sectional profile of the design surface at a selected position and orientation of the milling drum in a reference frame external to the construction machine, the cross-sectional profile being defined by the intersection of the design surface with an imaginary plane perpendicular to the longitudinal frame axis and including the axis of rotation of the milling drum;

[0010] (e) determining, with the controller, a preferred subset of sensors that can be used to create at least a portion of a cross-sectional profile of a designed surface at a selected position and orientation of the milling drum in a reference frame external to the construction machine, and the preferred subset of sensors having the highest priority ranking of all available subsets of sensors; and

[0011] (f) Automatically maintaining or switching control of milling depth using the controller to use a preferred subset of sensors.

[0012] In a second embodiment, in step (d), the selected position and orientation of the milling drum in a reference system external to the construction machine is the current position and orientation of the milling drum in a reference system external to the construction machine.

[0013] In a third embodiment, in step (d) the selected position and orientation of the milling drum in a reference system external to the construction machine is a predicted future position and orientation of the milling drum in a reference system external to the construction machine.

[0014] In a fourth embodiment, in step (d), the selected position and orientation of the milling drum in a reference system external to the construction machine is a predicted future position and orientation of the milling drum in a reference system external to the construction machine, and step (f) is performed at least when the milling drum reaches the predicted future position and orientation of the milling drum in the reference system external to the construction machine.

[0015] In a fifth embodiment, in step (d), the selected position and orientation of the milling drum in a reference system external to the construction machine is a predicted future position and orientation of the milling drum in the reference system external to the construction machine, and step (f) is performed before the milling drum reaches the predicted future position and orientation of the milling drum in the reference system external to the construction machine.

[0016] In a sixth embodiment, step (e) of the first embodiment may include: (e)(1) determining a subset of all sensors that can be used to generate at least a portion of a cross-sectional profile of a designed surface at a selected position and orientation of a milling drum in a reference frame external to the construction machine; and (e)(2) selecting the available subset with the highest priority ranking.

[0017] In a seventh embodiment, step (e) of the first embodiment may include: determining whether a subset of sensors with a highest priority ranking is available for creating at least a portion of a cross-sectional profile of a designed surface at a selected position and orientation of a milling drum in a reference frame external to the construction machine; if the subset of sensors with a highest priority ranking is available, selecting the subset of sensors with a highest priority ranking; and if the subset of sensors with a highest priority ranking is not available, determining whether a subset of sensors with a second highest priority ranking is available for creating at least a portion of a cross-sectional profile of a designed surface at a selected position and orientation of a milling drum in a reference frame external to the construction machine.

[0018] In an eighth embodiment, in step (b) of the first embodiment, the set of available sensors may include at least a left side plate sensor, a right side plate sensor, and a lateral tilt (s1ope) sensor, and possible subsets of sensors may include: (1) at least a left side plate sensor and a right side plate sensor; (2) a left side plate sensor and a lateral tilt sensor; and (3) a right side plate sensor and a lateral tilt sensor.

[0019] In a ninth embodiment which is a further modification of the eighth embodiment, in step (b), the priority rankings of multiple possible sensor subsets may be: the first priority ranking is the subset currently used; the second priority ranking is the left panel sensors and the right panel sensors; and the third priority ranking is any one of the remaining possible sensor subsets.

[0020] In a tenth embodiment as a further modification of the eighth embodiment, in step (b), the available sensor set may also include a left leading sensor in front of the milling drum and a right leading sensor in front of the milling drum. And the possible sensor subsets may also include: a left leading sensor and a right leading sensor; a left leading sensor and a lateral inclination sensor; a right leading sensor and a lateral inclination sensor; and a left leading sensor or a right leading sensor and an opposite side plate sensor.

[0021] In an eleventh embodiment which is a further modification of the tenth embodiment, in step (b), the priority rankings of multiple possible sensor subsets are: the first priority ranking is the subset currently used; the second priority ranking is the left side plate sensor and the right side plate sensor; the third priority ranking is the left leading sensor and the right leading sensor; the fourth priority ranking and the fifth priority ranking are the left side plate sensor or the right side plate sensor and the relative leading sensor; the sixth priority ranking and the seventh priority ranking are the left side plate sensor or the right side plate sensor and the lateral tilt sensor; and the eighth priority ranking and the ninth priority ranking are the left leading sensor or the right leading sensor and the lateral tilt sensor.

[0022] In any of the above embodiments, in step (d), the data representing the cross-sectional profile of the designed surface may include data representing the cross-sectional profile of the designed surface at a position laterally outside the milling drum.

[0023] In any of the above embodiments, in step (d), the data representing the cross-sectional profile of the designed surface may include data corresponding to the first and second ends of the milling drum and at least one intermediate point on the milling drum between the first and second ends.

[0024] In any of the above embodiments, in step (d), the data representing the cross-sectional profile of the designed surface may include data representing at least three points on the cross-sectional profile of the designed surface.

[0025] In any of the above embodiments, step (e) may include detecting discontinuities in the cross-sectional profile of the designed surface at selected positions and orientations of the milling drum in a reference system external to the construction machine.

[0026] In any of the above embodiments, step (e) may include detecting a discontinuity in the cross-sectional profile of the design surface at a selected position and orientation of the milling drum in a reference system external to the construction machine, and if the discontinuity is a crown of the cross-sectional profile located in the path of the milling drum, selecting a portion of the cross-sectional profile on one side of the discontinuity to be milled by the milling drum.

[0027] In any of the above embodiments, step (e) may include detecting a discontinuity in the cross-sectional profile of the design surface at a selected position and orientation of the milling drum in a reference system external to the construction machine, and if the discontinuity is a groove in the cross-sectional profile located in the path of the milling drum, selecting preliminary cutting by the milling drum so that no part of the milling drum is milled below the cross-sectional profile.

[0028] In any of the above embodiments, in step (e), the determination of the preferred subset of sensors may include determining that the preferred subset of sensors is both theoretically available and currently operational.

[0029] In any of the above embodiments, in step (a), the design surface dataset may include x, y and z coordinate data of the design surface.The design surface dataset may be in any coordinate system suitable for representing a geographical reference.

[0030] In another embodiment, a construction machine comprises a machine frame having a longitudinal frame axis extending between a front end and a rear end of the machine frame. A milling drum is supported by the machine frame and has a milling drum rotation axis perpendicular to the longitudinal frame axis. A controller is configured to control the milling depth of the milling drum as the construction machine moves across a ground surface, the controller storing in a memory a design surface data set defining a design surface to be created in a reference frame external to the construction machine, and a priority ranking of a plurality of possible sensor subsets selected from a set of available sensors, the controller further configured to: (a) determine data representing a cross-sectional profile of the design surface at a selected position and orientation of the milling drum in the reference frame external to the construction machine, the cross-sectional profile being defined by the intersection of the design surface with an imaginary plane perpendicular to the longitudinal frame axis and including the axis of rotation of the milling drum; (b) determine a preferred sensor subset that can be used to create at least a portion of the cross-sectional profile of the design surface at a selected position and orientation of the milling drum in the reference frame external to the construction machine and having the highest priority ranking of all available sensor subsets; and (c) automatically maintain or switch control of the milling depth to use the preferred sensor subset.

[0031]

[0006] Numerous objects, features and advantages of the embodiments set forth herein will become readily apparent to those skilled in the art when the following disclosure is read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a left side view of a construction machine, which is implemented as a road milling machine incorporating the utility model.

[0033] Figure 2 yes Figure 1 Schematic left side view of a road milling machine performing a milling operation, wherein the rear track of the road milling machine runs in the milling track.

[0034] Figure 3 yes Figure 2 Schematic rear view of the machine during the first milling pass.

[0035] Figure 4 yes Figure 3 Schematic rear view of a machine during a second milling pass adjacent to a first milling pass.

[0036] Figure 5 is a schematic plan view of a ground surface that has been milled in both a first pass and a second pass milling operation.

[0037] Figure 6is a schematic rear view of a milling machine positioned on top of a ground surface to be milled and indicating the design contour of the design surface below the ground surface. The design heights at the current x,y positions of the left and right ends of the milling drum and one midpoint of the milling drum are indicated by circled "Xs". Figure 6 In the case shown in , the designed surface profile under the milling drum is straight and the three "Xs" are aligned.

[0038] Figure 7 is a schematic rear view of a milling machine on top of a ground surface to be milled and indicating the design contour of the design surface below the ground surface. Figure 7 In the case shown in , the designed surface profile below the milling drum includes the crown.

[0039] Figure 8 is Figure 7 , where the design heights at the current x,y positions at the left and right ends of the milling drum and at one midpoint of the milling drum are indicated by circled "X". Figure 8 In the case shown in , the designed surface profile under the milling drum includes the crown and the three "Xs" are misaligned.

[0040] Fig. 9 is similar to Figure 8 , showing the position of the crown with an additional circled "X" which is now aligned with the "X" for the mid-point and the "X" for the right end of the milling drum.

[0041] Fig.10 is Figure 1-9 Schematic diagram of a controller with associated sensor inputs and control outputs in an embodiment of a milling machine.

[0042] Fig.11 is a schematic diagram of a control panel of a controller associated with a grade control system of a milling machine.

[0043] Fig.12 is similar to Figure 6-Figure 9 0026] Another schematic diagram of , but illustrating a technique for identifying a discontinuity in a designed surface proximate to a planned path of a milling machine.

[0044] Fig.13 is similar to Figure 8 , but illustrating the presence of a concave crown in the designed surface.

[0045] Fig.14 The concave crown portion is shown Fig.13 The same designed surface profile in which the milling machine mills the preliminary cuts, wherein both ends of the milling drum contact the profile such that no portion of the milling drum mills below the designed cross-sectional profile. DETAILED DESCRIPTION

[0046] The following disclosure describes several embodiments of a construction machine having a work implement for working on a ground surface. Figure 1-Figure 14 In the described embodiments, the construction machine may be a road milling machine, wherein the work implement is a milling drum.

[0047] Referring now to the drawings, and in particular to Figure 1 , a construction machine in the form of a road milling machine is shown and is generally designated by the number 10. The machine 10 comprises a machine frame 12. The machine frame 12 has a longitudinal frame axis 11 extending between a front end 13 and a rear end 15 of the machine frame 12. A plurality of ground engaging units 14, shown in the form of tracks, support the machine 10 from a ground surface 16. Wheeled ground engaging units may also be used. The ground engaging units 14 comprise two front ground engaging units 14a and two rear ground engaging units 14b. A plurality of lifting columns 17 support the machine frame 12 from the ground engaging units 14 in a height-adjustable manner.

[0048] The milling drum housing 20 is supported from the machine frame 12. A rotatable milling drum 22 is at least partially received by the milling drum housing 20 and is also supported from the machine frame 12. The milling drum 22 has an axis of rotation 23. Thus, the height of the machine frame 12 and the milling drum 22 relative to the ground surface 16 can be adjusted by adjusting the extension of the lifting column 17. On its left and right sides, the milling drum housing 20 is closed by a left and right height-adjustable side panel 24 and a right height-adjustable side panel 26 located near the left end 28 and the right end 30 of the milling drum 22. A height-adjustable scraper 29 can close the rear of the milling drum housing 20.

[0049] Figure 1 The ground working machine 10 shown in FIG. 1 is of the type commonly referred to as a large front loading milling machine, and also includes a first conveyor section 32 and a second conveyor section 34 for conveying milled material away from the milling drum 22. An operator station 36 can be carried on the machine frame 12, and a control panel 38 can be located at the operator station 36. A main engine 40 is located behind the operator station 36, which can be in the form of a diesel internal combustion engine or any other suitable power source. A direct belt drive (not shown) can connect the engine 40 to the milling drum 22 in a known manner. The direct belt drive can be located in the belt housing portion 42.

[0050] The construction machine 10 may carry at least one position data determining component 44 and 46 supported from the machine frame 12 and operable to determine position data defining the current position of a reference point on the machine in a reference frame external to the construction machine. In one embodiment, the at least one position data determining component includes at least two position data determining components 44 and 46 in the form of global navigation satellite system sensors, such as GPS sensors. In another embodiment, the position data determining components 44 and 46 may be reflectors configured for use with a laser-based robotic total station. By including at least two such position data determining components, the locations of the orientations of the two position data determining components allow the corresponding positions of all points on the machine 10 to be determined. Figure 1 and Fig.10 The x, y and z components of such a reference system outside the milling machine are schematically represented in . The x, y position may represent the position in the horizontal plane, while the z position may represent the vertical position relative to the horizontal plane. Figure 1 In FIG. 1 , the x-direction happens to be shown as corresponding to the forward direction of the milling machine and the longitudinal frame axis 11 , but this is purely coincidental and not essential.

[0051] Controller:

[0052] The position signals from sensors 44 and 46 may be received in a controller 48 of construction machine 10, such as Fig.10 The controller 48 described herein is used with the road milling machine 10 to control the milling depth of the milling drum during a milling operation.

[0053] The controller 48 may also receive signals from height sensors 50 and 52 associated with the left and right side plates 24 and 26, respectively, corresponding to actual milling depths of the left and right ends 28 and 30, respectively. The height sensors 50 and 52 may be, for example, integral to hydraulic smart cylinders that support the side plates 24 and 26 relative to the machine frame 12. The controller 48 may also receive signals from a gravity-based inclination sensor 54 that indicate the lateral inclination of the machine frame 12. As further explained below, the controller 48 may send command signals to left and right lifting columns (e.g., left and right rear lifting columns 17) to adjust the actual milling depths of the left and right ends 28 and 30 of the milling drum 22.

[0054] In another embodiment, the construction machine 10 may include a left leading sensor 51 in front of the milling drum 22 near the left end of the milling drum and a right leading sensor 53 in front of the milling drum 22 near the right end of the milling drum. Figure 2 The left leading sensor 51 and the right leading sensor 53 are schematically shown in FIG. Fig.10Schematically shown in . The left leading sensor 51 and the right leading sensor 53 may be ground engaging sensors associated with a hold-down mechanism in front of the milling drum 22. An example of such a leading sensor is shown in U.S. Patent Application Publication No. 2019 / 0025037 to Dzomo et al., the details of which are incorporated herein by reference. The left leading sensor 51 and the right leading sensor 53 may, for example, be integrated in a smart hydraulic cylinder associated with a ground engaging ski located in front of the milling drum.

[0055] like Fig.10 As schematically shown in FIG. 1 , construction machine 10 includes a control system 56 that includes controller 48. Controller 48 may be part of a machine control system of construction machine 10, or it may be a separate control module. Controller 48 may be associated with control panel 38 located at operator station 36. Controller 48 is configured to receive input signals from various sensors, such as sensors 44, 46, 50, 51, 52, 53, and 54 already described. Signals transmitted from the various sensors to controller 48 are transmitted in Fig.10 Schematically indicated in FIG. 4 by lines connecting the sensors to the controller, with arrows indicating the flow of signals from the sensors to the controller 48 .

[0056] Similarly, the controller 48 will generate control signals for controlling the operation of various actuators (such as the lifting columns 17 associated with the rear ground engaging units 14b) which are activated at the Fig.10 4 is schematically indicated by lines depicted in the diagram connecting the controller 48 to the various actuators, with arrows indicating the flow of command signals from the controller 48 to the respective actuators. It will be appreciated that to control the hydraulic cylinder type actuators, the controller 48 may send electrical signals to an electro / mechanical control valve (not shown) that controls the flow of hydraulic fluid to and from the hydraulic cylinders.

[0057] The controller 48 includes or may be associated with a processor 58, a computer readable medium 60, a database 62, and an input / output module or control panel 38 having a display 64. An input / output device 66, such as a keyboard, joystick, or other user interface, is provided so that an operator can input instructions to the controller. It should be understood that the controller 48 described herein may be a single controller having all of the functions described, or it may include multiple controllers, wherein the functions are distributed among the multiple controllers.

[0058] The various operations, steps or algorithms described in conjunction with the controller 48 may be directly embodied in hardware, a computer program product 68 (such as a software module executed by the processor 58), or a combination of the two. The computer program product 68 may reside in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a removable disk, or any other form of computer-readable medium 60 known in the art. An exemplary computer-readable medium 60 may be coupled to the processor 58 so that the processor can read information from the memory / storage medium and write information to the memory / storage medium. In an alternative, the medium may be integrated into the processor. The processor and the medium may reside in an application specific integrated circuit (ASIC). The ASIC may reside in a user terminal. In an alternative, the processor and the medium may reside in a user terminal as discrete components.

[0059] The term "processor" as used herein may refer to at least a general purpose or special purpose processing device and / or logic as would be understood by one skilled in the art, including but not limited to a microprocessor, a microcontroller, a state machine, etc. A processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0060] The control panel 38 may include, for example, a grade control system 72 of the milling machine 10. Fig.11 . The slope control system 72 may be, for example, a LevelPro slope control system developed by Wirtgen GmbH, the applicant of the present application. Such a slope control system 72 is further described in U.S. Pat. No. 8,308,395, the details of which are incorporated herein by reference. The operator of the milling machine may control the desired milling depth at each end 28 and / or 30 of the milling drum 22 by inputting the depth (e.g., 2.0°) into the slope control system 72. Alternatively, the operator may input the desired milling depth at one end of the milling drum plus the desired lateral slope of the milling drum. Fig.11A control panel 38 is shown through which an operator can input a set value for the milling depth of the end of the milling drum and / or the transverse slope of the milling drum. As further explained in U.S. Pat. No. 8,308,395, the center input device 78 can be formatted for inputting the transverse slope or the left or right milling depth. The left input device 74 can be formatted for inputting the left milling depth or transverse slope. The right input device 76 can be formatted for inputting the right milling depth or transverse slope. As further described below, the controller 58 can automatically generate those inputs for the desired milling depth and / or transverse slope and input those values ​​into the grade control system 72. The grade control system 72 then uses any of several combinations of available input sensors to maintain the selected milling depth, typically two sensors selected from the left side plate sensor 50, the right side plate sensor 52, and the gravity-based transverse slope sensor 54, or two sensors selected from the left leading sensor 51, the right leading sensor 53, and the gravity-based transverse slope sensor 54.

[0061] Build the project model:

[0062] When planning a road milling or other construction project, a survey may be performed on the ground area where the milling is to be performed. This may be, for example, an initial survey of an area where a road or airport is to be built, etc. This initial survey data set may identify a series of points on the ground surface 16, which are identified by x, y and z coordinates in a local ground-based reference system. These surveys may be provided to a planning bureau or design office, which may use the initial survey to plan the project. The "z" coordinate for each point is the actual height of the point in the local ground-based reference system.

[0063] A planning bureau or design office can plan a construction project and create a project design data set, which includes a design surface data set that identifies the desired final height of the ground and identifies the project to be built on the ground (e.g., a paved road or other structure). Part of this design work is to create a description of the desired milling surface to be created by a road milling machine. The desired surface can be identified by a design surface data set of a series of desired milling points in a defined area, which are identified by the desired x, y and z coordinates in a reference system based on the local ground. The "z" coordinate for each point is the expected height of the point in the reference system based on the local ground. The databases are each usually in the form of a set of triangles, each triangle being defined by the absolute x, y, z information for three angles defined in an external reference system independent of the milling machine. For the "actual data set" that defines the existing ground surface, the size of the triangle is usually on the order of a few millimeters to a few inches. For the "design surface data set", the triangle can be much larger and can be larger than the milling machine so that the milling machine can be located on a single triangle.

[0064] Alternative forms of the design surface data set may also be used. For example, instead of describing the design surface with x, y, z values, the design surface may be described by defining key points of interest such as crown lines. For example, a road surface may be defined by the start point, axis, slope (which may include longitudinal inclination and / or transverse slope) and cross-sectional shape of the road profile. Such a design surface description may be converted to x, y, z data on or off the construction machine.

[0065] Additionally, discontinuities in the designed surface may be extracted from the x, y, z data and provided to the controller 48 as additional information, thereby eliminating the need to detect such discontinuities on the fly while the construction machine 10 is operating.

[0066] Milling depth control technology:

[0067] Various techniques have been developed for controlling the milling depth of a milling drum to produce a designed surface. One preferred technique, as further described below, involves generating a milling depth data set that generates x, y and milling depth data. Using such a milling depth data set, the milling depth is controlled to a desired value depending on the sensed x, y position of the milling drum. Another technique is that shown, for example, in U.S. Pat. No. 9,039,320, in which a desired milling drum height is determined in a reference frame external to the construction machine, and the height of the milling drum is controlled to the desired height in the design data set.

[0068] When using the preferred technique, an x,y milling depth dataset and milling depth data can be created. The milling depth dataset can be used Fig.10The milling depth dataset is prepared by a separate processor 70 schematically shown in FIG. 1 (ie, not the processor 58 located on the milling machine 10) and may be prepared prior to loading the milling depth dataset on the controller 48 of the milling machine 10. The milling depth dataset is not created in real time during the milling operation.

[0069] Thus, for example, a planning bureau creating a design surface dataset describing a desired milling surface can create a milling depth dataset by comparing an initial survey dataset with the design surface dataset describing the desired milling surface. Similarly, a milling depth dataset can be created on or near a construction site by comparing an initial survey dataset with the design surface dataset describing the desired milling surface 81. It should also be noted that the milling depth dataset can be updated during a milling operation. For example, it may be decided to perform a desired milling operation in two cuts instead of one. Thus, if the initial milling depth is 4 cm at a particular x, y position, it may be desirable to perform two passes of approximately 2 cm each. The first pass may be performed at a first milling depth of less than 4 cm. The controller can then update the milling depth dataset by subtracting the depth of the initial cut from the initial milling depth. Then in the second pass, the updated milling depth dataset will be used to control the cut to the final total desired milling depth.

[0070] It will be appreciated that the local ground-based coordinate system in which the initial survey and design surface data sets are created may not be the same coordinate system as the global navigation satellite system in which the sensors 44 and 46 operate, but the correlation of positions in the local ground-based coordinate system relative to positions in the global navigation satellite system is known and one or other data set may be transformed as necessary for comparison with signals in the selected reference system of the sensors 44 and 46 used.

[0071] The milling depth dataset and the designed surface dataset may then be loaded into the memory 60 of the controller 48 on the milling machine 10. The milling depth dataset and the designed surface dataset may be loaded into the memory 60 of the milling machine 10 via a wireless connection. Alternatively, the milling depth dataset and the designed surface dataset may be loaded onto the memory 60 of the milling machine 10 by placing the milling depth dataset and the designed surface dataset on a portable data storage device such as a memory stick and then transferring the data from the portable data storage device to the memory 60 of the milling machine 10. This may be described as providing the milling depth dataset and the designed surface dataset to the controller 48. As used herein, "providing" a dataset to the controller 48 includes making the dataset accessible to the controller 48 in any manner, and the dataset need not be stored in a memory integral to the controller.

[0072] It is not necessary to provide an initial survey data set to the controller 48 of the milling machine 10 .

[0073] In one embodiment, the separate processor 70 may be associated with an online portal created as a service to the owner / operator of the milling machine 10. The machine owner / operator and / or a surveyor and / or planning bureau working with the machine owner may upload their survey datasets and design surface datasets to the online portal. The separate processor 70 may then create a milling depth dataset and format the milling depth dataset and the design surface dataset for use by the milling machine 10. When the owner / operator of the milling machine 10 is ready to perform a milling operation, the milling depth dataset and the design surface dataset may be wirelessly downloaded from the separate processor 70 of the online portal to the controller 48 of the milling machine 10.

[0074] The road milling machine 10 may then perform the following steps: Figure 2-Figure 5 10 . The road milling machine can be equipped with GPS or other GNSS sensors 44 and 46 onboard the milling machine 10, which are used to determine the position of the milling machine as the milling machine 10 moves across the ground surface 16. More specifically, the GNSS system can determine the x, y position of each end 28 and 30 of the milling drum 22 in a reference system external to the milling machine 10 (e.g., the global positioning coordinate system of a GPS system). Those x, y positions of the ends 28 and 30 of the milling drum 22 can be associated with the x, y positions of the milling depth dataset and the design surface dataset. Based on the x, y positions of the ends 28 and 30 of the milling drum 22 detected by the sensors 44 and 46, the controller 48 can determine the desired milling depth and desired lateral slope at each end of the milling drum as follows, and those input values ​​can be fed to the grade control system 72 of the milling machine 10.

[0075] Based on the x, y position of the left end 28 of the milling drum 22 , the controller 48 may look up the desired milling depth at that position in the (x, y, milling depth) data set and may feed that value to the left milling depth input 74 of the grade control system 72 .

[0076] Based on the x, y position of the right end 30 of the milling drum 22 , the controller 48 may look up the desired milling depth at that position in the (x, y, milling depth) database and may feed that value to the right milling depth input 78 of the grade control system 72 .

[0077] Based on the x, y positions of the left and right ends 28, 30 of the milling drum 22, and optionally based on at least one point between the left and right ends, the controller 48 can look up the design height at each of those points in the design surface database and determine the design cross slope, and can feed that value to the cross slope input 76 of the grade control system 72. The desired cross slope for any given position of the milling drum 22 corresponding to any given x, y position of the left and right ends 28, 30 of the milling drum 22 can be determined in several ways, as described below with reference to Figure 6-Figure 9 As further described.

[0078] Figure 5 A plan view schematically showing a "first pass" milling operation and an overlapping "second pass" milling operation. The "first pass" is indicated by the shaded area with a "1" in the arrow. The "second pass" is indicated by the shaded area with a "2" in the arrow. Figure 3 is a schematic rear cross-sectional view showing the milling machine 10 during a “first pass”. Figure 4 is a schematic rear cross-sectional view showing the milling machine 10 during a “second pass”.

[0079] In such Figure 3 In a typical "first pass" milling operation shown in , the milling machine 10 can start on the uncut actual surface 16, with both side plates 24 and 26 resting on the uncut surface 16. First, the operator of the milling machine can "zero" the grade control system 72. This is achieved by lowering the machine frame 12 and the milling drum 22 until the milling drum 22 first contacts the surface to be milled 16. This setting of the extension of the lifting column 17 and this position of the side plates 24 and 26 is set to a "zero" milling depth.

[0080] The grade control system 72 then uses any of many possible combinations of sensor inputs to perform actual milling depth control for the desired milling depth. For example, the grade control system 72 may use two side plate sensors 50 and 52, or the grade control system 72 may use the lateral slope sensor 54 and the side plate sensor 50 or 52. Alternatively, the grade control system 72 may use two leading sensors 51 and 53, or the grade control system may use the lateral slope sensor 54 and the leading sensor 51 or 53. Other grade sensors, such as ultrasonic or laser sensors (not shown), may also be used if available.

[0081] In such Figure 3 After this "first pass" milling operation as seen in FIG. 1 , the milling machine 10 may be used in a Figure 4, where there is no control over any quantified milling depth. In a typical "second pass" milling operation, the right side plate 26 is allowed to run over the previous cut surface 80 of the "first pass", and the milling depth at the right end of the milling drum is set to zero to match the previous cut surface 80. The grade control system 72 can then control the actual cross slope to the desired cross slope using the gravity-based cross slope sensor 54.

[0082] Determination of the required transverse slope and cross-sectional profile of the design surface:

[0083] For any given x, y position of the two ends 28 and 30 of the milling drum 22, the desired lateral inclination angle of the milling drum 22 can be determined by knowing the design surface height at these two positions, as long as the design surface is planar between these two positions. However, the design surface may have a "crown", shoulder or other discontinuity between the two positions, in which case the lateral inclination determined by comparing only the two end positions may be erroneous. Shoulders or other discontinuities between the two positions, in which case the lateral inclination determined by comparing only the two end positions may be erroneous. This problem can be solved by including at least one intermediate point between the two ends 28 and 30 in the lateral inclination analysis. The intermediate point can, for example, be the midpoint between the two ends. This process is described in detail in detail in the accompanying drawings. Figure 6-Figure 9 It is schematically shown in the figure.

[0084] In addition, if Fig.12 As schematically illustrated in FIG, the design height (elevation) along a line in the x, y plane can be analyzed for points located laterally outside the end of the milling drum to identify the presence of non-linearities in the design surface immediately adjacent to the planned path of the milling machine. This allows the machine operator to modify the planned path to improve milling efficiency. In addition, the machine operator can select different sensors to guide the milling depth control.

[0085] It will be appreciated that the desired transverse slope discussed above is the transverse slope required for the milling drum 22 to create the planned surface when the milling drum reaches the discussed position within the reference frame external to the construction machine 10. More generally, the present disclosure proposes a technique for determining, using the controller 48, data representing a cross-sectional profile 82 of a designed surface 81 at a selected position and orientation of the milling drum 22 in a reference frame external to the construction machine 10, the cross-sectional profile 82 being defined by the intersection of the designed surface with an imaginary plane P that is perpendicular to the longitudinal frame axis 11 and includes the axis of rotation 23 of the milling drum 22. Figure 1 and Fig.10 In the orientation shown in , where the longitudinal frame axis 11 is oriented parallel to the x-direction of the external reference system, plane P is the y, z-plane of the external reference system.

[0086] The desired position and desired transverse slope of the milling drum 22 in the z-direction to produce the designed surface depends on the direction of travel of the milling machine 10. The controller 48 can determine the direction of travel from the first position data determining component 44 and the second position data determining component 46. In addition, the controller 48 can determine data representing a cross-sectional profile 82 of the designed surface at any selected position and orientation of the milling drum 22 in a reference frame external to the construction machine 10, the cross-sectional profile 82 being defined by the intersection of the designed surface with an imaginary plane P. The selected position and orientation of the milling drum 22 can be the current position and orientation, or it can be some predicted future position and orientation of the milling drum in the expected path of the milling drum 22 ahead of its current position. As will be seen in the further discussion below, the ability of the controller 48 to determine what the cross-sectional profile of the designed surface beneath the milling drum is now and in the future allows the controller 48 to select the most desirable subset of sensors for controlling the milling depth at any given time.

[0087] Figure 6 Schematically shown is a rear view of a milling machine 10 standing on an existing ground surface 16. At the shown position and orientation of the milling drum 22 in a reference system external to the construction machine 10, the cross-sectional profile of the design surface defined by its intersection with an imaginary plane P, which is perpendicular to the longitudinal frame axis 11 and includes the rotation axis 23 of the milling drum 22, is schematically indicated by 82. This may also be referred to as the cross-sectional profile of the design surface 81 immediately below the milling drum 22.

[0088] Points on the cross-sectional profile 82 of the design surface 81 below the left end 28 of the milling drum 22 are indicated by an "X" numbered 84. Points on the cross-sectional profile 82 of the design surface 81 below the right end 30 of the milling drum 22 are indicated by an "X" numbered 86. Points on the cross-sectional profile 82 of the design surface 81 below the midpoint of the milling drum 22 are indicated by an "X" numbered 88. The controller 48 is configured to compare points 84, 86, and 88 and determine whether they are located on a straight line. If they are located on a straight line, this indicates that there is no "crown" or other discontinuity between the endpoints, and the desired lateral slope is the slope of the line through the three points. In addition, the vertical distance of those points below the milling drum 22 is the desired milling depth at which the milling drum 22 will mill the existing ground surface to the appropriate level to create the desired design surface.

[0089] Figure 7 There is schematically shown a rear view of the milling machine standing on a ground surface, but this time standing over a portion of a cross-sectional profile 82 of a designed surface 81 including a crown 90 . Figure 8The schematic diagram shows the comparison of these three points by the controller 48, which will determine that the three points are not in a straight line. Once the controller 48 determines that the three points are not in a straight line, the next step is to determine the position of the crown 90. This can be done by checking the intermediate point inward from one of the outer points 84 and 86 until the design height is found to align with the other end point and the intermediate point 88. Fig. 9 This process is shown where the left point 84 has moved inwards until it is at the crown 90, at which point the three points 84, 86 and 88 are found to be in a straight line. Fig. 9 In the example seen in , the desired lateral slope is determined as the slope of a line passing through three points 84 , 86 and 88 .

[0090] The controller 48 can of course also be configured to select the slope to the left of the crown 90 as the design slope. Figure 7-Figure 9 In the case of, the controller can be configured to select the desired transverse slope as the slope of the longest length below the milling drum 22, which is Fig. 9 In the example of the embodiment of the present invention, the slope is on the right side of the crown 90. The controller 48 can also be configured to select one of the slopes adjacent to the previously milled portion, or the controller 48 can be configured so that the slope to the right or left side of the crown 90 can be selected by the operator. The controller 48 can also be provided with information describing the previous milling pass and may determine that the design surface on one side of the crown 90 has been formed, in which case the controller will select the settings required to mill the remaining slope on the other side of the crown 90.

[0091] Fig.12 The schematic diagram shows another alternative for checking the design height of a point located laterally outside the length of the milling drum 22 along a line defined by the x, y positions of the two ends of the milling drum. In the embodiment shown, the controller can be configured to check the design milling depth height along a line extending between an x, y position spaced laterally a distance 92 from the left side of the milling drum 22 and an x, y position spaced laterally a distance 94 from the right side of the milling drum 22. The distances 92 and 94 can be, for example, in the range of 0 to 3 meters, or more preferably can be in the range of 10 cm to 20 cm. Similar to the above for Figure 7-Figure 9 In the manner described, the designed surface heights 96 and 98 at those x, y locations can be compared to the designed surface height 88 at the midpoint on the milling drum 22. In this manner, the controller 48 can identify the location of the crown or other discontinuity 90 that falls within the lateral distance 94 from the right side of the milling drum 22. This information can be displayed to the operator and / or utilized by the controller 48 to modify the planned path of the milling machine 10 or select a different subset of sensors to guide milling depth control.

[0092] The controller can also detect concave crown conditions, such as Fig.13 In this case, similar to the above described method for detecting Figure 8 and Fig. 9 In the case of the position of crown 90 in the concave portion, the controller can move point 86 inward until it is aligned with points 84 and 88 to identify the position of concave crown 100.

[0093] Prioritization of possible sensor subsets:

[0094] It will be appreciated that while there are a number of choices of sensors available for controlling the milling depth of the milling drum 22 , some subsets may be more preferred than others for various reasons.

[0095] In one embodiment, it may be preferred to keep using the currently used subset of sensors if it is available for the current control situation and if it is available for the expected control situation immediately before the current position of the milling drum. Using the currently used subset may be preferred because it avoids the need to replace the active control sensors and thereby avoids possible interruption of the milling operation.

[0096] In another embodiment, it is preferred to use a milling depth sensor (such as the side plate sensors 50 and 52 or the leading sensors 51 and 53 ) rather than the lateral slope sensor 56 to control the milling depth due to the higher accuracy of the milling depth sensor.

[0097] In yet another embodiment, it is preferred to use one or both of the side plate sensors 50 and 52 rather than the leading sensors 51 and 53 to control the milling depth because the side plate sensors are located closer to the plane P and thus more directly measure the actual milling depth. Due to the location of the leading sensors 51 and 53 in front of the plane P, they may experience inaccuracies due to uneven existing ground surfaces or due to the longitudinal tilt of the machine frame 12 that is not exactly parallel to the ground surface.

[0098] In another embodiment, if the milling depth controller is to use a lateral pitch sensor 56, it may be preferred to use the right side plate sensor 52 instead of the left side plate sensor 50 or it may be preferred to use the right leading sensor 53 instead of the left leading sensor 51 in conjunction with the lateral pitch sensor 56 because the right side plate sensor 52 or the right leading sensor 53 may be closer to the right end of the milling drum 22 and more directly visible to the operator of the milling machine 10. As those skilled in the art will appreciate, milling machines are typically designed so that the right end of the milling drum 22 can mill closest to obstacles and is less likely to be obstructed by a typical belt and pulley drive system that drives the milling drum 22 from the left side of the milling machine 10.

[0099] Based on these factors and any other factors that may be present, the controller 48 may be provided with a priority ranking of a plurality of possible sensor subsets selected from the set of available sensors. The priority ranking may be stored in the memory 60 of the controller 48 and provided by the controller 48 looking up the priority ranking in the memory 60. The operator of the milling machine 10 may also be allowed to modify the stored priority ranking via the operator interface 66.

[0100] For example, if the available sensor set includes only side panel sensors 50 and 52 and lateral tilt sensor 56, possible sensor subsets include: (1) left panel sensor 50 and right panel sensor 52; (2) left panel sensor 50 and lateral tilt sensor 56; and (3) right panel sensor 52 and lateral tilt sensor 56. Using those possible sensor subsets, the priority order may be:

[0101] - The first priority order is the subset currently used;

[0102] - The second priority order is the left side panel sensor 50 and the right side panel sensor 52;

[0103] - The third priority order is the right side panel sensor 52 and the lateral tilt sensor 56; and

[0104] - The fourth priority ranking is the left side sill sensor 50 and the lateral tilt sensor 56 .

[0105] In another example, if the set of available sensors also includes left leading sensor 51 and right leading sensor 53, the possible sensor subsets also include: (4) left leading sensor 51 and right leading sensor 53; (5) right leading sensor 53 and lateral tilt sensor 56; (6) left leading sensor 51 and lateral tilt sensor 56; (7) right side panel sensor 52 and left leading sensor 51; and (8) left side panel sensor 50 and right leading sensor 53. Using these additional possible sensor subsets, the priority order of the possible sensor subsets can be:

[0106] - The first priority order is the subset currently used;

[0107] - The second priority order is the left side panel sensor 50 and the right side panel sensor 52;

[0108] - The third priority ranking is the left leading sensor 51 and the right leading sensor 53;

[0109] - The fourth priority ranking is the right side panel sensor 52 and the left leading sensor 51;

[0110] - The fifth priority ranking is the left side plate sensor 50 and the right leading sensor 53;

[0111] - The sixth priority ranking is the right side plate sensor 52 and the lateral tilt sensor 56;

[0112] - The seventh priority ranking is the left side plate sensor 50 and the lateral tilt sensor 56;

[0113] - the eighth priority ranking is the right leading sensor 53 and the lateral slope sensor 56; and

[0114] The ninth priority ranking is the left leading sensor 51 and the lateral inclination sensor 56 .

[0115] It will be appreciated that the above examples are merely examples and that the operator of the milling machine or the person setting up the controller 48 may select any desired prioritization to be provided to the controller.

[0116] Determination of available subsets:

[0117] It will be appreciated that depending on various factors, including the cross-sectional profile 82 of the designed surface 81 and whether the profile includes discontinuities (such as crown 90 or concave crown 100), some subsets of sensors may be available to create the desired milling surface corresponding to the designed surface, while some subsets may not be available.

[0118] For example, consider Figure 3 , Figure 4 and Figure 6 , where the cross-sectional profile 82 to be cut is a straight line from one end 28 to the other end 30 of the milling drum 22. Assuming that the available sensor set includes the left plate sensor 50, the right plate sensor 52, and the lateral slope sensor 54, any two of these sensors can be used to cut the profile 82 between the cutting points 84 and 86.

[0119] In another example, considering Figure 7-Figure 9 In the case of the crown 90 shown in FIG. 1 , it may be desirable to generate a portion of the cross-sectional profile 82 between the point 86 below the right end 30 of the milling drum 22 and the crown point 90. Assuming that the available sensor set includes the left side plate sensor 50, the right side plate sensor 52, and the transverse slope sensor 54, the only available combination may be the right side plate sensor 52 and the transverse slope sensor 54, because the available milling depth data for the left side plate sensor 50 cannot be used to mill the plane between 86 and 90.

[0120] In yet another example, considering Figure 13-14 In the case of the groove or concave crown 100 shown in FIG. 1 , it may be desirable to perform the following steps: Fig.14 , so that no portion of the milling drum 22 is milled below the cross-sectional profile 82. For example, Fig.13As seen in FIG. 1 , the left and right plate sensors 50 and 52 may be used to make a preliminary cut, wherein the left and right ends 28 and 30 of the milling drum 22 cut to a depth of points 84 and 86. This will leave an uncut area 102 to be cut in a later pass. Fig.14 For the cut shown, the only usable combination would be a left side plate sensor 50 and a right side plate sensor 52 .

[0121] Another example of a situation where a sensor cannot be used to perform the desired milling is where one of the side plate sensors is located outside the area of ​​the design surface data set so that no data is available for the desired milling depth at the location of that side plate.

[0122] The controller 48 may also determine that no subset of sensors is available for performing the desired milling cut. For example, two side panels may be outside the area of ​​the design surface data set. In this case, the controller 48 may provide a warning or alarm to the operator of the milling machine.

[0123] There are other situations where sensors may not be available. A side plate sensor may be running on an already milled surface. The ground beneath one of the milling depth sensors may not be available for reference: a side plate sensor may be running on an irregular shoulder that is blocked by debris; a lead sensor may not be available due to debris in front of the milling drum. The machine may detect inconsistent sensor readings and automatically decide not to use certain sensors, or the operator may decide not to use certain sensors because he becomes aware of these conditions before the machine. Any of this information, which may be detected by the milling machine using appropriate sensors or which is otherwise available to the controller, may be used by the controller to automatically determine a preferred subset of sensors that may be used to create at least a portion of the cross-sectional profile of the designed surface.

[0124] Control method:

[0125] In one embodiment, the method of controlling the construction machine 10 may include the following steps:

[0126] (a) providing a design surface data set to the controller 48, the design surface data set defining a design surface to be created in a reference system (x, y, z) external to the construction machine;

[0127] (b) providing to the controller 48 a prioritization of a plurality of possible subsets of sensors selected from the set of available sensors;

[0128] (c) performing a milling operation with the milling drum 22 as the construction machine moves over the ground surface 16;

[0129] (d) determining, with the controller 48, data representing a cross-sectional profile 82 of a design surface 81 at a selected position and orientation of the milling drum 22 in a reference frame external to the construction machine 10, the cross-sectional profile 82 being defined by the intersection of the design surface with an imaginary plane P that is perpendicular to the longitudinal frame axis 11 and includes the axis of rotation 23 of the milling drum 22;

[0130] (e) determining, using the controller 48, a preferred subset of sensors that can be used to create at least a portion of a cross-sectional profile 82 of a designed surface 81 at a selected position and orientation of the milling drum 22 in a reference frame external to the construction machine and that has the highest priority ranking of all available sensor subsets; and

[0131] (f) Automatically maintain or switch control of milling depth using controller 48 to use a preferred subset of sensors.

[0132] With respect to the above step (a) of providing the controller 48 with a design surface data set defining a design surface to be created in a reference frame (x, y, z) external to the construction machine, it will be appreciated that the design surface data set may be provided directly as described above, or may be provided indirectly by providing other data from which the design surface data is derived. For example, a milling machine may be provided with an actual surface data set defining an existing surface, and a milling depth data set, and data suitable for the design surface may then be derived by subtracting the milling depth from the actual surface height.

[0133] It will be appreciated that switching the control of the milling depth with the controller 48 can be performed in a manner similar to that disclosed in U.S. Pat. No. 8,308,395 to Jurasz et al., the details of which are incorporated herein by reference. With such a system, the controller 48 can switch from control based on a first selected subset of a plurality of available sensors to control based on a preferred subset of sensors during a milling operation without interrupting the milling operation and without making any erratic changes to the control signals sent to the lifting column 17.

[0134] In one embodiment, in step (d), the selected position and orientation of the milling drum 22 in a reference system external to the construction machine 10 may be the current position and orientation of the milling drum 22 in a reference system external to the construction machine.

[0135] In another embodiment, in step (d), the selected position and orientation of the milling drum 22 in a reference system external to the construction machine 10 may be a predicted future position and orientation of the milling drum 22 in a reference system external to the construction machine.

[0136] In such an embodiment using a predicted future position and orientation of the milling drum 22, step (f) may be performed at least when the milling drum reaches the predicted future position and orientation of the milling drum in a reference system external to the construction machine.

[0137] In another embodiment using the predicted future position and orientation of the milling drum 22, step (f) may be performed before the milling drum reaches the predicted future position and orientation of the milling drum in a reference frame external to the construction machine.

[0138] It will be appreciated that step (e) may be performed in a variety of ways. In one embodiment, step (e) may further comprise:

[0139] (e)(1) determining a subset of all sensors that can be used to create at least a portion of a cross-sectional profile 82 of a designed surface 81 at a selected position and orientation of the milling drum 22 in a reference frame external to the construction machine 10; and

[0140] (e)(2) Select the available subset with the highest priority ranking.

[0141] In another embodiment, step (e) may further comprise:

[0142] determining whether the subset of sensors having the highest priority ranking can be used to create at least a portion of a cross-sectional profile 82 of a designed surface 81 at a selected position and orientation of the milling drum 22 in a reference frame external to the construction machine;

[0143] If a subset of sensors with a highest priority ranking is available, selecting the subset of sensors with a highest priority ranking; and

[0144] If the highest priority sensor subset is not available, it is determined whether a next highest priority sensor subset is available to create at least a portion of a cross-sectional profile of the designed surface at a selected position and orientation of the milling drum in a reference frame external to the construction machine.

[0145] It will be appreciated that, in Fig.12 In the case shown in , the data representing the cross-sectional profile 82 of the designed surface 81 used in step (d) may include data representing the cross-sectional profile 82 at locations such as 96 and 98 laterally outside the milling drum 22. In one embodiment, the data representing the cross-sectional profile 82 of the designed surface used in step (d) may include two points such as 96, 96' or 98, 98' laterally outside the milling drum 22 on each side of the milling drum. Using multiple points on each lateral side of the milling drum 22 helps identify discontinuities located outside the length of the milling drum 22.

[0146] like Figure 6-Figure 9As seen in FIG. 8 , data representing the cross-sectional profile 82 of the design surface used in step (d) may include data at points 84 and 86 corresponding to the first end 28 and the second end 30 of the milling drum 22, as well as data at at least one intermediate point on the milling drum 22 between the first end and the second end, which intermediate point is directly above point 88.

[0147] The data representing the cross-sectional profile 82 of the designed surface used in step (d) may be described as comprising data representing at least three points 84 , 86 , 88 on the cross-sectional profile 82 of the designed surface.

[0148] like Figure 7-Figure 9 and Figure 13-14 As seen in FIG. 1 , step (e) may include detecting a discontinuity in the cross-sectional profile 82 of the design surface at a selected position and orientation of the milling drum 22 in a reference frame external to the construction machine. The discontinuity may be as follows: Figure 7-Figure 9 The crown 90 as seen in Figure 13-14 or any other discontinuity from a straight line. Another type of discontinuity may be a step in the ground surface formed by a previous milling pass, parallel to the current pass or transverse to the current pass.

[0149] If the discontinuity is a crown 90 of the cross-sectional profile 82 that is located in the path of the milling drum 22 , the method may include selecting a portion of the cross-sectional profile 82 on one side of the discontinuity 90 to be milled by the milling drum 22 .

[0150] If the discontinuity is a groove 100 of the cross-sectional profile 82 located in the path of the milling drum 22, the method may include selecting a preliminary cut by the milling drum 22, such as Fig.14 As seen in FIG. 8 , no portion of the milling drum 22 is milled below the cross-sectional profile 82 .

[0151] It will be appreciated that another factor to be considered in the ultimate selection of the subset of sensors to be used at any time includes determining that the preferred subset of sensors is both theoretically available and currently operable. If a given sensor is not currently operable due to equipment failure or environmental obstruction, etc., the selection process moves to the next most desirable subset of available sensors that can be used. An example of an environmental obstruction to the operability of a given sensor is that a side panel sensor cannot be used because the side panel is running on an irregular surface such as a soft shoulder of a road.

[0152] As previously described, the prioritization may rank any currently used subset of sensors as the highest priority in order to avoid unnecessary changes of sensors. Alternatively, the controller may look at the cross-sectional profile of the design surface in the path ahead of the current position of the milling drum and determine that there will be a future change required to a subset of sensors that has a higher priority ranking than the currently used subset. In this case, since a change of sensors will be required anyway, the controller may go ahead and make a change from the currently used subset to a preferred subset that will be required in the future.

[0153] Thus, it can be seen that the apparatus and method of the present disclosure readily achieve the objects and advantages mentioned as well as those inherent therein. Although certain preferred embodiments of the present disclosure have been shown and described for the purposes of the present invention, many changes may be made to the arrangement and construction of the parts and steps by those skilled in the art, and these changes are included within the scope and spirit of the present disclosure as defined by the appended claims. Each disclosed feature or embodiment may be combined with any other disclosed feature or embodiment.

Claims

1. A construction machine, characterized in that: include: a machine frame having a longitudinal frame axis extending between a front end and a rear end of the machine frame; a milling drum supported from said machine frame and having a milling drum rotation axis perpendicular to said longitudinal frame axis; a controller configured to control a milling depth of the milling drum as the construction machine moves across a ground surface, the controller having stored in a memory a design surface data set defining a design surface to be created in a reference frame external to the construction machine and a priority ranking of a plurality of possible subsets of sensors selected from a set of available sensors, the controller further configured to: (a) determining, in a reference system external to the construction machine, at a selected position and orientation of the milling drum, data representing a cross-sectional profile of the design surface, the cross-sectional profile being defined by the intersection of the design surface with an imaginary plane perpendicular to the longitudinal frame axis and including the axis of rotation of the milling drum; (b) determining a preferred subset of sensors that can be used to create at least a portion of a cross-sectional profile of a designed surface at a selected position and orientation of the milling drum in a reference frame external to the construction machine and that has the highest priority ranking of all available sensor subsets; as well as (c) Automatically maintain or switch control of milling depth to use a preferred subset of sensors.

2. The construction machine according to claim 1, characterized in that: The selected position and orientation of the milling drum (22) in a reference system external to the construction machine is the current position and orientation of the milling drum in a reference system external to the construction machine.

3. The construction machine according to claim 1, characterized in that: The selected position and orientation of the milling drum (22) in a reference frame external to the construction machine is a predicted future position and orientation of the milling drum in a reference frame external to the construction machine.

4. The construction machine according to claim 3, characterized in that The controller (48) is also configured to: Control of the milling depth is automatically maintained or switched to use a preferred subset of sensors at least when the milling drum (22) reaches a predicted future position and orientation of the milling drum in a reference frame external to the construction machine.

5. The construction machine according to claim 3, characterized in that The controller (48) is also configured to: Control of the milling depth is automatically maintained or switched to use of the preferred subset of sensors before the milling drum reaches a predicted future position and orientation of the milling drum in a reference frame external to the construction machine.

6. The construction machine according to claim 1, characterized in that In order to determine a preferred subset of sensors that can be used to create at least a portion of a cross-sectional profile of a designed surface at a selected position and orientation of a milling drum (22) in a reference frame external to the construction machine and that has the highest priority ranking of all available subsets of sensors, the controller (48) is further configured to: (1) determining a subset of all sensors that can be used to create at least a portion of a cross-sectional profile (82) of a designed surface at a selected position and orientation of a milling drum (22) in a reference frame external to the construction machine; as well as (2) Select the available subset with the highest priority ranking.

7. The construction machine according to claim 1, characterized in that In order to determine a preferred subset of sensors that can be used to create at least a portion of a cross-sectional profile of a designed surface at a selected position and orientation of a milling drum (22) in a reference frame external to the construction machine and that has the highest priority ranking of all available subsets of sensors, the controller (48) is further configured to: determining whether the subset of sensors having the highest priority ranking can be used to create at least a portion of a cross-sectional profile (82) of a designed surface at a selected position and orientation of a milling drum (22) in a reference frame external to the construction machine; If the sensor subset with the highest priority ranking is available, then the sensor subset with the highest priority ranking is selected; as well as If the highest priority sensor subset is not available, determining whether the next highest priority sensor subset can be used to create at least a portion of a cross-sectional profile (82) of a designed surface at a selected position and orientation of a milling drum (22) in a reference frame external to the construction machine.

8. The construction machine according to claim 1, characterized in that: The set of available sensors includes at least: Left side plate sensor (50); a right side panel sensor (52); and a lateral tilt sensor (56); and A possible subset of sensors includes at least: a left side plate sensor (50) and a right side plate sensor (52); a left side panel sensor (50) and a lateral tilt sensor (56); and Right side panel sensor (52) and lateral tilt sensor (56).

9. The construction machine according to claim 8, characterized in that: The priority order of the plurality of possible sensor subsets stored in the memory (60) is: The first priority order is the subset currently in use; The second priority order is the left side panel sensor (50) and the right side panel sensor (52); and The third priority ranking is any one of the remaining possible sensor subsets.

10. The construction machine according to claim 8, characterized in that: The set of available sensors also includes: a left leading sensor (51) located in front of the milling drum (22); and a right leading sensor (53) located in front of the milling drum (22); and Possible sensor subsets also include: A left leading sensor (51) and a right leading sensor (53); A left leading sensor (51) and a lateral tilt sensor (56); and Right leading sensor (53) and lateral tilt sensor (56).

11. The construction machine according to claim 10, characterized in that: The priority order of the plurality of possible sensor subsets stored in the memory (60) is: The first priority order is the subset currently in use; The second priority order is the left side panel sensor (50) and the right side panel sensor (52); The third priority ranking is the left leading sensor (51) and the right leading sensor (53); The fourth priority ranking and the fifth priority ranking are one of the left side plate sensor (50) and the right side plate sensor (52) and the left leading sensor (51) or the right leading sensor (53) on the opposite side; The sixth and seventh priority rankings are the left side plate sensor (50) or the right side plate sensor (52) and the lateral tilt sensor (56); and The eighth priority and the ninth priority are the left leading sensor (51) or the right leading sensor (52). A guide sensor (53) and a lateral inclination sensor (56).

12. The construction machine according to claim 1, characterized in that: The data representing the cross-sectional profile of the designed surface stored in the memory (60) includes data representing the cross-sectional profile (82) of the designed surface at a location laterally outside the milling drum (22).

13. The construction machine according to claim 1, characterized in that: The data representing the cross-sectional profile of the designed surface determined by the controller (48) includes data corresponding to a first end (28) and a second end (30) of the milling drum (22) and at least one intermediate point on the milling drum between the first end and the second end.

14. The construction machine according to claim 1, characterized in that: The data representing the cross-sectional profile (82) of the designed surface determined by the controller (48) includes data representing at least three points on the cross-sectional profile (82) of the designed surface.

15. The construction machine according to claim 1, characterized in that In order to determine a preferred subset of sensors that can be used to create at least a portion of a cross-sectional profile of a designed surface at a selected position and orientation of a milling drum (22) in a reference frame external to the construction machine and that has the highest priority ranking of all available subsets of sensors, the controller (48) is further configured to: Discontinuities in a cross-sectional profile (82) of a designed surface are detected at selected positions and orientations of a milling drum (22) in a reference frame external to the construction machine.

16. The construction machine according to claim 15, characterized in that The controller (48) is also configured to: If the discontinuity is a crown of a cross-sectional profile (82) in the path of the milling drum (22), a portion of the cross-sectional profile (82) on one side of the discontinuity is selected to be milled by the milling drum (22).

17. The construction machine according to claim 15, characterized in that The controller (48) is also configured to: If the discontinuity is a groove in the cross-sectional profile (82) in the path of the milling drum (22), the preliminary cut by the milling drum is selected so that no part of the milling drum is milled below the cross-sectional profile.

18. The construction machine according to claim 1, characterized in that: In order to determine a preferred sensor subset that can be used to create at least a portion of a cross-sectional profile of a designed surface at a selected position and orientation of a milling drum (22) in a reference frame external to the construction machine and has the highest priority ranking of all available sensor subsets, the controller (48) is configured to determine the preferred sensor subset that is both theoretically usable and currently operable.

19. The construction machine according to claim 1, characterized in that: The design surface data set stored in the memory (60) includes x, y and z coordinate data of the design surface.

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