Patent Application
20230340736
The present application relates to a construction machine having a working implement for working a ground surface and to methods of operation of such a construction machine.
The planning and implementation of a construction project to create a design surface from an existing ground surface has traditionally been performed in a series of manually controlled operations. Such a design surface may be a milled surface created in a milling operation or it may be a paved surface created in a paving operation.
In the example of a road milling project, first a survey is done of the area of the ground where the milling is to take place. This may for example be the initial survey done of an area where a road or airport or the like is to be constructed. This initial survey data set may identify a series of points on the ground surface which are identified by x, y and z co-ordinates in the local ground based reference system. Such surveys are commonly done and provided to a planning bureau or design office which may use the initial survey to plan a project. The “z” co-ordinate for each point is the actual elevation of that point in the local ground based reference system. This initial survey data set may also be referred to as an “actual data set”.
The planning bureau or design office may plan the construction project and create a project design data set which includes a design surface data set that identifies the desired final elevation of the ground surface, and which identifies the project (e.g. a pavement or other structure) to be constructed on the ground surface. One part of this design work is to create a description of the desired milled surface to be created by the road milling machine. This desired surface may be identified by a design surface data set defining a series of desired milled points in the area which are again identified by x, y and z co-ordinates in the local ground based reference system. The “z” co-ordinate for each point is the desired elevation of that point in the local ground based reference system. The data sets are each typically in the form of a set of triangles, each triangle being defined by the absolute x,y,z information for the three corners defined in an external reference system independent of the milling machine. For the “actual data set” defining the existing ground surface the dimensions of the triangles are typically on the order of a few millimeters up to a few inches. For the “design surface data set” the triangles may be much larger and may be larger than the milling machine so that it is possible the milling machine will be located on a single triangle. The size of the triangles may vary within the same project, depending on the surface roughness. The rougher the surface the smaller the triangles should be in order to create the best representation of the actual surface. Scanning is a common method of surveying such an actual surface.
Prior to beginning the milling operation, a surveyor may return to the area to be milled and may locate a number of points on the original ground surface and survey those points to identify the x, y and z co-ordinates of each point in the local ground based reference system. The surveyor will then calculate, based upon the data defining the desired milled surface and the data defining the actual ground surface, the milling depth which is necessary at each point. The surveyor may physically write the desired milling depth on the ground surface adjacent the marked point, such as with a can of spray paint. The marking is typically a spray painted “X” with a spray painted number next to it indicating the desired milling depth at that location.
The milling machine operator then observes the desired milling depth written on the ground surface and adjusts the milling depth of the milling machine accordingly as the point is reached. The operator of the milling machine controls the desired milling depth at each end of the milling drum by inputting that depth, e.g., 2.0”, into a grade control system, such as for example the LevelPro control system developed by Wirtgen GmbH, the assignee of the present invention. Alternatively, the operator can input desired milling depth at one end of the milling drum plus desired cross slope of the milling drum. The grade control system then maintains the selected milling depth using any of several combinations of available input sensors, typically two sensors selected from the left sideplate sensor, right sideplate sensor and gravity based cross slope sensor. Other sensors may also be used.
There have been attempts to automate parts of this process. One such attempt is that seen in Snoeck U.S. Pats. No. 8961065 and No. 9039320. In the Snoeck patents the actual elevation of the bottom of each end of the milling drum is determined and is then controlled based on a comparison to the design elevation for the design surface at the locations of each end of the milling drum.
There is a continuing need for improvements in such automated systems, and particularly there is a need for a system which avoids the need for determination of the actual elevation of the milling drum during the milling operation.
In one embodiment a working depth data set of x, y and working depth data may be created. The working depth data set may be prepared with a separate processor (i.e. not the processor located on the construction machine) and may be prepared prior to the loading of the working depth data set on the controller or associated memory of the construction machine. The working depth data set is not created in real time during the working operation. In the case of a milling operation the working depth is the milling depth. In the case of a paving operation the working depth is the paving depth.
Thus, for example, the planning bureau which creates the design surface data set describing the desired milled or paved surface, may create the working depth data set by a comparison of the initial survey data set with the design surface data describing the design surface. Similarly, the working depth data set may be created on or near the jobsite, by a comparison of the initial survey data set with the design surface data set describing the design surface.
The working depth data set and the design surface data set may then be loaded into a memory associated with a controller on the construction machine. The working depth data set and the design surface data set may be loaded onto the memory associated with the construction machine by wireless connection. Alternatively, the working depth data set and the design surface data set may be loaded onto the memory associated with the construction machine by placing the same on a portable data storage device such as a memory stick or the like. It is not necessary to load the initial survey data set onto the controller of the construction machine.
The construction machine may then perform a ground working operation. The construction machine may be equipped with a GPS or other global navigation satellite system (GNSS) sensor onboard the construction machine that is used to determine the construction machine location as it moves across the ground surface. More particularly the GNSS system may determine the x,y position of each end of the working implement. Based upon those x, y positions the controller may determine desired working depths at each end of the working implement and the desired cross slope as follows and may feed those input values to the grade control system of the construction machine.
Based upon the x, y position of the left end of the working implement the controller may look up the desired working depth at that location in the x, y, working depth data set, and may feed that value to a left side working depth input of the grade control system.
Based upon the x, y position of the right end of the working implement the controller may look up the desired working depth at that location in the x, y, working depth data set, and may feed that value to a right side working depth input of the grade control system.
Based upon the location of the working implement corresponding to the x, y positions of the left and right ends of the working implement the controller may look up the design elevation at selected points in the design surface database along a line in the x, y plane extending through those x, y locations and the controller may determine the desired cross slope for the working implement and may feed that value to a cross slope input of the grade control system.
It is also possible to do similar calculations in advance so long as the future path of the construction machine is known. The desired working depth and the desired cross slope for the expected future positions of the construction machine may be determined from the working depth data set and from the design surface data set by looking at the expected x, y positions of the left and right ends of the working implement along the future path. This can be used to provide a preview for the operator of the upcoming changes in working depth.
On a typical “first pass” working operation in the context of a milling machine the milling machine may begin on the uncut actual surface with both sideplates resting on the uncut surface. First the operator of the milling machine may “zero” the grade control system. This is accomplished by lowering the machine frame and the milling drum until the milling drum first touches the surface to be milled. This setting of the extension of the lifting columns and this position of the sideplate(s) is set as “zero” milling depth.
The grade control system then does the actual milling depth control to the desired milling depth using any one of many possible combinations of sensor inputs.
After such a “first pass” milling operation the milling machine may be operated in a “second pass” mode wherein there is no control to any quantified milling depth. In a typical “second pass” milling operation the right sideplate is allowed to run on the previously cut surface and the milling depth of the right end of the milling drum is set to zero to match the previously cut surface. The grade control system may then use the gravity based cross slope sensor to control the actual cross slope to the desired cross slope.
Numerous objects, features and advantages of the embodiments set forth herein will be readily apparent to those skilled in the art upon reading of the following disclosure when taken in conjunction with the accompanying drawings.
The following disclosure describes multiple embodiments of a construction machine having a working implement for working a ground surface. In one embodiment as described with regard to
Referring now to the drawings, and particularly to
A 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. Thus, a height of the machine frame 12 and the milling drum 22 relative to the ground surface 16 are adjustable by adjusting an extension of the lifting columns 17. On its left and right sides, the milling drum housing 20 is closed by left and right adjustable height sideplates 24 and 26 located adjacent left and right ends 28 and 30 of milling drum 22. A height adjustable scraper blade 29 may close a rear of the milling drum housing 20.
The earth working machine 10 shown in
The construction machine 10 may carry at least one position data determination component 44 and 46, supported from the machine frame 12 and operable to determine position data to define a current position of a reference point on the machine in a reference system external to the construction machine. In one embodiment the at least one position data determination component includes at least two position data determination components 44 and 46 in the form of Global Navigation Satellite System sensors, for example GPS sensors. In another embodiment the position data determination 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 determination components the position of the locations of the two position data determination components allow the corresponding positions of all points on the machine 10 to be determined. The x, y and z components of such a reference system external to the milling machine are schematically represented in
Position signals from the sensors 44 and 46 may be received in a controller 48 of the construction machine 10 as schematically shown in
The controller 48 may also receive signals from height sensors 50 and 52 associated with the left and right sideplates 24 and 26, respectively, which signals correspond to actual milling depths of the left and right ends 28 and 30, respectively. The height sensors 50 and 52 may for example be integral to hydraulic smart cylinders which support the sideplates 24 and 26 relative to the machine frame 12. Controller 48 may also receive a signal from a gravity based slope sensor 54 indicative of a cross-slope of the machine frame 12. As is further explained below the controller 48 may send command signals to the left and right lifting columns, for example the 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.
As schematically illustrated in
Similarly, the controller 48 will generate control signals for controlling the operation of the various actuators such as the lifting columns 17 associated with rear ground engaging units 14b, which control signals are indicated schematically in
Controller 48 includes or may be associated with a processor 58, a computer readable medium 60, a data base 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 the human operator may input instructions to the controller. It is understood that the controller 48 described herein may be a single controller having all of the described functionality, or it may include multiple controllers wherein the described functionality is distributed among the multiple controllers.
Various operations, steps or algorithms as described in connection with the controller 48 can be embodied directly in hardware, in a computer program product 68 such as a software module executed by the processor 58, or in a combination of the two. The computer program product 68 can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, or any other form of computer-readable medium 60 known in the art. An exemplary computer-readable medium 60 can be coupled to the processor 58 such that the processor can read information from, and write information to, the memory/ storage medium. In the alternative, the medium can be integral to the processor. The processor and the medium can reside in an application specific integrated circuit (ASIC). The ASIC can reside in a user terminal. In the alternative, the processor and the medium can reside as discrete components in a user terminal.
The term “processor” as used herein may refer to at least general-purpose or specific-purpose processing devices and/or logic as may be understood by one of skill in the art, including but not limited to a microprocessor, a microcontroller, a state machine, and the like. A processor can also be implemented as a combination of computing devices, e.g., 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.
The control panel 38 may for example include a control panel as schematically shown in
When a road milling or other construction project is planned a survey may be done of the area of the ground where the milling is to take place. This may for example be the initial survey done of an area where a road or airport or the like is to be constructed. This initial survey data set may identify a series of points on the ground surface 16 which are identified by x, y and z co-ordinates in the local ground based reference system. Such surveys may be provided to a planning bureau or design office which may use the initial survey to plan a project. The “z” co-ordinate for each point is the actual elevation of that point in the local ground based reference system.
The planning bureau or design office may plan the construction project and create a project design data set which includes a design surface data set that identifies the desired final elevation of the ground surface, and which identifies the project (e.g. a pavement or other structure) to be constructed on the ground surface. One part of this design work is to create a description of the desired milled surface to be created by the road milling machine. This desired surface may be identified by a design surface data set defining a series of desired milled points in the area which are again identified by x, y and z co-ordinates in the local ground based reference system. The “z” co-ordinate for each point is the desired elevation of that point in the local ground based reference system. The databases are each typically in the form of a set of triangles, each triangle being defined by the absolute x,y,z information for the three corners defined in an external reference system independent of the milling machine. For the “actual data set” defining the existing ground surface the dimensions of the triangles are typically on the order of a few millimeters up to a few inches. For the “design surface data set” the triangles may be much larger and may be larger than the milling machine so that it is possible the milling machine will be located on a single triangle.
In one embodiment of the present invention a milling depth data set of x, y and milling depth data may be created. The milling depth data set may be prepared with a separate processor 70 schematically shown in
Thus, for example, the planning bureau which creates the design surface data set describing the desired milled surface, may create the milling depth data set by a comparison of the initial survey data set with the design surface data set describing the desired milled surface. Similarly, the milling depth data set may be created on or near the jobsite, by a comparison of the initial survey data set with the design surface data set describing the desired milled surface 82. It is also noted that the milling depth data set may be updated during a milling operation. For example, it may be decided to perform a desired milling operation in two cuts rather than one. Thus, if the initial milling depth is 4 cm at a particular x, y location, it might be desired to do that it two passes of about 2 cm each. A first pass may be made at a first milling depth less than 4 cm. The controller may then update the milling depth data set by subtracting the depth of the initial cut from the initial milling depth. Then on a second pass the updated milling depth data set will be used to control the cut to the final total desired milling depth.
Similarly, the planning bureau may create a paving depth data set to describe a layer of paving to be created on the ground surface to create a final paved ground surface. The layer of paving may for example be placed upon a previously milled surface. So in a first instance there may be a design surface data set defining a milled surface to be created, and in a second instance there may be a second design surface data set describing a paved surface to be created on top of the milled surface. The paving depth data set may be in the form of x, y and paving depth data.
It will be appreciated that the local ground based coordinate system in which the initial survey and the design surface data set 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 correlations of the positions in the local ground based coordinate system relative to positions in the Global Navigation Satellite System are known and the one or the other data sets may be converted as necessary for comparison to signals in the selected reference system of the sensors 44 and 46 being used.
The milling depth data set and the design surface data set may then be loaded into the memory 60 of the controller 48 on the milling machine 10. The milling depth data set and the design surface data set may be loaded onto the memory 60 of the milling machine 10 by wireless connection. Alternatively, the milling depth data set and the design surface data set may be loaded onto the memory 60 of the milling machine 10 by placing the same on a portable data storage device such as a memory stick or the like 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 data set and the design surface data set to the controller 48. As used herein “providing” a data set to the controller 48 includes in any way making the data set accessible by the controller 48, and it is not necessary that the data set be stored in a memory integral to the controller.
It is not necessary to provide the initial survey data set to the controller 48 of the milling machine 10.
In one embodiment the separate processor 70 may be associated with an online portal created as a service to owner/operators 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 data set and design surface data set to the online portal. Then the separate processor 70 may create the milling depth data set and format the milling depth data set and the design surface data set for use with the milling machine 10. When the owner/operator of the milling machine 10 is ready to perform the milling operation the milling depth data set and the design surface data set may be wirelessly downloaded from the separate processor 70 of the online portal to the controller 48 of the milling machine 10.
The road milling machine 10 may then perform a ground milling operation as schematically illustrated in
Based upon 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 location in the (x, y, milling depth) data set, and may feed that value to the left side milling depth input 74 of the grade control system 72.
Based upon 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 location in the (x, y, milling depth) database, and may feed that value to the right side milling depth input 78 of the grade control system 72.
Based upon the x, y positions of the left and right ends 28 and 30 of the milling drum 22, and optionally at least one point between the left and right ends, the controller 48 may look up the design elevation at each of those points in the design surface database and determine a design cross slope and may feed that value to the cross slope input 76 of the grade control system 72. The desired cross-slope for any given location of the milling drum 22 corresponding to any given x, y positions of the left and right ends 28 and 30 of the milling drum 22 may be determined in several ways as further described below with reference to
On a typical “first pass” milling operation as represented in
The grade control system 72 then does the actual milling depth control to that desired milling depth using any one of many possible combinations of sensor inputs. For example the grade control system 72 may use the two sideplate sensors 50 and 52, or the grade control system 72 may use the cross-slope sensor 54 and one of the sideplate sensors 50 or 52. Other grade sensors such as ultrasonic or laser sensors (not shown) may also be used if available.
After such a “first pass” milling operation as seen in
For any given x, y positions of the two ends 28 and 30 of the milling drum 22 the desired cross-slope angle for the milling drum 22 can be determined by knowing the design surface elevation at those two positions, so long as the design surface is planar between those two positions. There is the possibility, however, that the design surface might have a “crown”, a shoulder or other discontinuity between those two positions in which case a cross-slope determined only by comparing those two end positions might be in error. This problem can be solved by including in the cross-slope analysis at least one intermediate point between the two ends 28 and 30. This intermediate point may for example be a mid-point between the two ends. This procedure is schematically illustrated in
Furthermore, as schematically illustrated in
It is of course also possible that the controller 48 could be configured to choose the slope to the left side of the crown 90 as the design slope. In situations like that of
This detailed example of methods of operation is set forth in the context of the use of the road milling machine 10 to control a milling depth of the milling drum during a milling operation. As previously noted this can more generally be referred to as controlling a working depth of a working implement during a working operation, and it will be understood that it is also applicable to the embodiment of an asphalt paving machine in which the controller controls a paving depth, i.e. paving thickness, of a paving screed during a paving operation.
A method of controlling the construction machine 10 including the machine frame 12, the milling drum 22 supported from the machine frame 12, and the controller 48 configured to control the milling depth of the milling drum 22 as the machine moves across the ground surface 16, may comprise:
The method may further include determining the current x, y position in the reference system external to the construction machine 10 of at least one intermediate point on the milling drum 22 between the first and second ends of the milling drum during the milling operation. The intermediate point may be above point 88 in
In the above method the step (h) may further include determining from the design surface data set the desired cross-slope for the milling drum 22 at the current x, y positions of the first and second ends 28, 30 of the milling drum 22 based upon a design elevation of the design surface 82 at the current x, y position of the at least one intermediate point 88 and based on a design elevation of the design surface at the current x, y position of one of the first and second ends as schematically shown in
Alternatively, in the above method step (h) may include:
As a further alternative in the above method, step (h) may include determining from the design surface data set the desired cross-slope for the milling drum 22 at the current location of the milling drum 22 based upon a plurality design elevations of the design surface along a line extending through and beyond the design elevation of the design surface at the current x, y positions of the first and second ends 28 and 30 of the milling drum 22, as schematically shown and described above regarding
The methods described above may further include prior to step (a), preparing the milling depth data set by comparing the design surface data set to a survey data set including actual x, y and z coordinates of an existing ground surface 16 to be milled to create the design surface 82.
In the above methods the survey data set is preferably not provided to the controller 48.
In the above methods steps (d) and (e) may be performed using a global navigation satellite system.
In the above methods the milling operation of step (c) may be a first pass milling operation as shown in
The above methods may further include performing a second pass milling operation 2 as schematically illustrated in
Referring now to the drawings, and particularly to
In a front region of the machine frame 112 as seen in the working direction A, a reservoir 116 for holding the material to be laid is arranged. Located at the rear of the road paving machine 110 is a screed 118 for laying the material. The paving screed 118 may be described as a working implement 118 of the paving machine 110. The driver’s platform 120 is arranged between the reservoir 116 and the screed 118.
The screed 118 may be configured as a board floating on the material to be laid. For this purpose, the screed 118 is connected to the machine frame 112 by pivot arms 122 so that the screed 118 may move up and down relative to machine frame 112 by pivoting the pivot arms 122 relative to machine frame 112. Pivot actuators 124 may be connected between the machine frame 112 and each of the pivot arms 122 to control this pivotal movement. The desired paving depth or thickness is achieved, in particular, via adjustment of the setting angle of the screed 118, which is determined by the height of a screed traction point. To adjust the screed traction point, the actuators 124 are provided on the sides of the machine frame 112. With the actuators 124, not only the setting angle of the screed 118 but also the incline or cross-slope of the screed 118 can be set transversely to the direction of finishing A.
The paving machine 110 may carry at least one position data determination component 144 and 146, operable to determine position data to define a current position of the left and right ends of the screed 118 in a reference system external to the construction machine. In the embodiment of a paving machine the position data determination components may be located on the ends of the screed 118 or on the pivot arms 122 that move with the screed 118. It is noted that in the context of a paving machine this may be preferred, as contrasted to the milling machine 10 where the position data determination components were located on the machine frame. This is because in the paving machine 110 the working implement moves up and down relative to the machine frame whereas in the milling machine 10 the working implement may be vertically fixed relative to the frame. Thus, placement of the position data determination components on or adjacent the working implement may provide a more direct measure of the position of the working implement in the case of a paving machine. But it is noted that it is also possible to place the position data determination components on the machine frame, even with a construction machine such as an asphalt paving machine wherein the working implement is movable relative to the machine frame, in which case a sensor may be used to detect that relative movement and the controller may then determine the position of the working implement relative to the machine frame.
The paving depth 154 is determined by the height of the paving screed 118 above the ground surface which may be detected for example with ultrasonic sensors such as 156 mounted on the screed 118 or on a structure attached to the screed such as the pivot arms 122. As schematically shown in
Actual paving depth signals and actual cross-slope signals from sensors 156 and 158 may be received by a controller such as controller 48 located on the paving machine 110. The controller 48 may then generate control signals sent to the actuators 124 to raise or lower the pivot arms 122 and the ends of the screed 118 as needed to control the paving depth 154 in accordance with the paving depth data set and the design surface data set as described above. In
Thus, it is seen that the apparatus and methods of the embodiments disclosed herein readily achieve the ends and advantages mentioned as well as those inherent therein. While certain preferred embodiments have been illustrated and described for purposes of the present disclosure, numerous changes in the arrangement and construction of parts and steps may be made by those skilled in the art, which changes are encompassed within the scope and spirit of the present invention as defined by the appended claims.
