The present disclosure relates generally to a road construction machine and, more particularly, to a control system for a paving machine.
The present disclosure relates to paving machines that are used in road surface construction and repairs. Paving machines are typically utilized to lay asphalt or other paving material. Paving machines generally include a screed system for spreading and compacting a mat of paving material relatively evenly over a desired surface. However, various operating conditions of paving machines may affect the angle of attack and the cross slope of the screeds of paving machines. Paving with a screed at an incorrect angle of attack may cause increased wear on screed plates and tamper bars, as well as causing mat defects. Further, excessive cross slope may cause excessive twisting between left and right main frames of a screed, which may cause interference between screed components and restrict movement in various moving parts of paving machines.
U.S. Pat. No. 9,534,348, issued to Rio et al. on Jan. 3, 2017 (“the '348 patent”), describes a method of reducing paver transition marks produced by a paving machine. The method described in the '348 patent involves sensing transition marks in a mat and adjusting a screed position based on the sensed transition marks. However, the method of the '348 patent does not address the angle of attack or a cross slope of a screed determined by sensors located on the screed and the frame of a paving machine.
The disclosed methods and systems may solve one or more of the problems set forth above and/or other problems in the art. The scope of the current disclosure, however, is defined by the attached claims, and not by the ability to solve any specific problem.
In one aspect, a method for determining a change in an angle of attack of a screed on a paving machine may include determining a first angle of attack of the screed, determining a second angle of attack of the screed based on data from at least one sensor located on the screed and at least one sensor located on a frame of the paving machine, and determining a change in the angle of attack based on the first angle of attack and the second angle of attack. The method may also include providing a notification of at least one of the first angle of attack, the second angle of attack, or the change in the angle of attack.
In another aspect, a method for determining a change in an angle of attack of a screed on a paving machine may include determining a first angle of attack of the screed, determining a second angle of attack of the screed based on data from at least one sensor located on the screed, and determining a change in the angle of attack based on the first angle of attack and the second angle of attack. The method may also include automatically adjusting the angle of attack in response to the change in the angle of attack.
In yet another aspect, a system for a paving machine may include a screed, a sensor system arranged on the screed, and a controller for determining a change in an angle of attack of the screed or a cross slop. The controller may be configured to determine a first angle of attack of the screed, determine a second angle of attack of the screed based on data from the sensor system located on the screed, determine a change in the angle of attack based on the first angle of attack and the second angle of attack, and determine a cross slope of the screed based on data from a first sensor and a second sensor of the sensor system located on the screed. The controller may be further configured to provide a notification of at least one of the change in the angle of attack or the cross slope.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various exemplary embodiments and together with the description, serve to explain the principles of the disclosed embodiments.
Both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the features, as claimed. As used herein, the terms “comprises,” “comprising,” “having,” “including,” or other variations thereof, are intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements, but may include other elements not expressly listed or inherent to such a process, method, article, or apparatus. Moreover, in this disclosure, relative terms, such as, for example, “about,” “substantially,” “generally,” and “approximately” are used to indicate a possible variation of ±10% in the stated value.
For the purpose of this disclosure, the term “ground surface” is broadly used to refer to all types of surfaces that form typical roadways (e.g., asphalt, cement, clay, sand, dirt, etc.) or upon which paving material may be deposited in the formation of roadways. Although the current disclosure is described with reference to a paving machine, this is only exemplary. In general, the current disclosure can be applied to any machine that uses a screed-type system.
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Main screed 104 may include a main screed plate 110, 111 (main screed plate 111 is shown in
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Additionally, controller 201 may include a determination module 202. Determination module 202 may be configured to receive various inputs. The various inputs may be signals received from, for example, at least left and right inclinometers 240, 242 and/or machine frame inclinometer 129. Determination module 202 may also receive input data 204, for example, from averaging skis (not shown in the figures) attached to paving machine 100. The averaging skis may provide, for example, reference data of the paving ground surface that paving machine 100 may utilize to adjust the positions of tow arms 116, 117 via tow point 140 during a paving operation. Input data 204 may also include operation control signals of paving machine 100, for example, a speed of paving machine 100, tow arm position control signal, deflector height control signal, etc. Determination module 202 may determine, based on the machine operation control signals, a desired angle of attack of screed assembly 102. Additionally, determination module 202 may determine an actual angle of attack 212 based on the data received from inclinometers 240, 242. Determination module 202 may also determine an angle of attack adjustment value 215 based on actual angle of attack 212 and the desired angle of attack of screed assembly 102. Additionally or alternatively, determination module 202 may utilize, in addition to inclinometers 240, 242, the signals received from machine frame inclinometer 129 and/or averaging skis in determining actual angle of attack 212. In another aspect, determination module 202 may determine a cross slope 213 based at least on the received input signals from inclinometers 240, 242.
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The disclosed aspects of system 200 and method 500 described herein may be used before or during operation of any paving machine used in a variety of settings. In particular, system 200 of paving machine 100 described herein may monitor a change in the angle of attack and the cross slope of screed assembly 102 in order to provide notification of the change in the angle of attack and the cross slope. Additionally, system 200 may automatically adjust the operation commands of paving machine 100 in order to prevent negative effects of an incorrect angle of attack and excessive cross slope of screed assembly 102 on paving machine 100. The negative effects may include, for example, but not limited to, erratic screed behavior, paving material density issues, open texture in a paving mat, increased wear of screed components, and/or paving mat defects.
In step 502, determination module 202 may determine a first angle of attack of screed assembly 102 prior to performing paving operation by paving machine 100. The first angle of attack may include desired angle of attack 302. Desired angle of attack 302 may be determined based on various paving machine 100 operating control signals received from the operator.
In step 504, determination module 202 may determine a second angle of attack of screed assembly 102 based on data from at least one sensor located on screed assembly 102. In one aspect, the second angle of attack may be determined in real-time during a paving operation, and the second angle of attack may include actual angle of attack 212. The at least one sensor may include inclinometers 129, 240, 242, or any other sensor capable of detecting a relative angle of screed assembly 102 and/or paving machine 100 with respect to an operating ground surface of paving machine 100. In one aspect, the second angle of attack may be determined based on data received from a single inclinometer mounted on a frame of main screed 104 of screed assembly 102. Alternatively, the second angle of attack may be determined based at least on two inclinometers, including at least one inclinometer mounted on screed assembly 102 and at least one inclinometer mounted on a frame of paving machine 100. Inclinometer 129 mounted on the frame of paving machine 100 may detect a relative angle of paving machine 100 with respect to an operating ground surface of paving machine 100. Determination module 202 may incorporate the relative angle of paving machine 100 detected by inclinometer 129 into the sensor data obtained from inclinometers 240, 242 to improve the accuracy of the angle of attack determination. In another aspect, determination module 202 may additionally utilize the data received from the averaging skis of paving machine 100 to determine the second angle of attack.
In step 506, determination module 202 may determine a change in the angle of attack of screed assembly 102 based on a difference between the first angle of attack and the second angle of attack. Determination module 202 may determine, in step 508, whether the change in the angle of attack exceeds a predetermined threshold value. Additionally or alternatively, in step 510, determination module may determine a cross slope (or a twist angle) of screed assembly 102 based on data from at least two sensors (e.g., inclinometers 240, 242) mounted on screed assembly 102. For example, a cross slope may be determined based on a comparison of measured twist from inclinometers 240, 242 or other sensors associated with left screed frame 222 and right screed frame 223. In one aspect, one of the at least two sensors may be mounted on left screed frame 222 and at least another one of the at least two sensors may be mounted on right screed frame 223. In step 512, determination module 202 may determine whether the change in the cross slope exceeds a predetermined threshold value.
In step 509, system 200 may automatically adjust the angle of attack of screed assembly 102 and/or provide a notification of the change in the angle of attack in response to the difference between the first angle of attack and the second angle of attack. That is, if the change in the angle of attack exceeds the predetermined threshold value, system 200 may automatically adjust the angle of attack of screed assembly 102. However, if the change in the angle of attack does not exceed the predetermined threshold value, the method 500 may restart from step 502. The angle of attack of screed assembly 192 may be automatically adjusted, for example, by adjusting at least (1) a tamper bar speed, (2) a counter balance of screed assembly, (3) a pre-strikeoff height, and/or (4) a head of paving material. The counter balance of screed assembly may be adjusted by adjusting the hydraulic pressures applied to the screed lift cylinders. The pre-strikeoff height may be adjusted by adjusting the vertical position of deflector 115. The head of paving material may be adjusted by controlling the amount of paving material fed to screed assembly 102. Additionally, in step 514, system 200 may address the change in the cross slope and/or provide a notification regarding the cross slope based on the determination result of step 512. For example, system 200 may address the change in the cross slope by preventing further tow point 140 movement in the direction of a higher cross slope or twist angle when the change in the cross slope exceeds a predetermined threshold value. Additionally or alternatively, system 200 may automatically adjust the cross slope of screed assembly 102 by adjusting pressures applied to the tow point cylinders 141 to raise or lower tow point 140 when the change in the cross slope exceeds a predetermined threshold value. Alternatively or additionally, the cross slope may also be adjusted by adjusting thickness screws 118, 119 or by adjusting depth cranks.
In steps 509 and 514, determination module 202 may provide a notification regarding the angle of attack and the cross slope, respectively. The notification may be provided to the operator of paving machine 100 visually on a display or by sound via at least a speaker. In one aspect, the notification regarding the angle of attack may be a display listing an actual angle of attack or a change in the angle of attack from a desired/present angle of attack (e.g., angle of attack above a predetermined threshold). Additionally, a notification regarding the cross slope may be a display listing an actual cross slope or a change in the cross slope from a desire/present cross slope (e.g., cross slope above a predetermined threshold) or a textual notification or alarm notification of cross slope outside the predetermined threshold. Moreover, the notification may include a real-time angle of attack 212 or a real-time cross slope 213 of screed assembly that may be provided on a display 134 of the paving machine 100. The notification may be provided when the change in the angle of attack or the cross slope exceeds a predetermined threshold value. Additionally or alternative, the angle of attack of screed assembly 102 may be adjusted manually by the operator of paving machine 100. For example, before paving machine 100 performs a paving operation or while paving machine 100 is stationary, the operator may, based on the change in the angle of attack of screed assembly 102 provided in the notification, input appropriate operation commands to adjust tow point 140 height, adjust thickness screws 118, 119 to null screed assembly 102, change pre-strikeoff height, and/or add counter balance to screed assembly 102. Any of the described manual adjustments, singly or in combination, may affect the angle of attack of screed assembly 102.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed system without departing from the scope of the disclosure. Other embodiments of the system will be apparent to those skilled in the art from consideration of the specification and practice of the system disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.