Control system for a paving machine

A paving system includes a paving machine and a controller. The paving machine includes a drive assembly, a paving material delivery system, including a hopper, a conveyor assembly, an auger, and a screed assembly, and at least one material sensor configured to monitor a delivery of paving material from the hopper to the auger by the conveyor assembly. The controller is coupled to the at least one material sensor and the conveyor assembly to control the delivery of paving material from the hopper to a ground surface.

TECHNICAL FIELD

The present disclosure relates generally to a road construction machine, and more particularly, to a control system for a paving machine.

BACKGROUND

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 often involves a material feed system installed on the paving machine. The material feed system may feed paving material from a hopper to a screed. The material feed system may include one or more conveyor assemblies and one or more augers that are located adjacent to the screed such that the one or more conveyor assemblies and augers can deliver paving material to be spread by the screed to form a mat of paving material. The amount of paving material and the rate at which the paving material is delivered to the screed affects the thickness of the mat of paving material. Additionally, the amount of paving material and the rate at which the paving material is delivered to the screed may affect the cost and/or quality of the paving operation.

U.S. Pat. No. 10,227,738 (hereinafter referred to as “the '738 patent”) discloses a road paver that includes a layer thickness detecting device coupled to the screed. The layer thickness detecting device of the '738 patent includes a first sensor for detecting a first distance from the applied material layer and a second sensor for detecting a second distance from the foundation below the applied material layer. With the information from the first and second sensors, the paver of the '738 patent can determine a thickness of the layer of paving material that has been spread by the screed. However, the '738 patent does not determine an amount of paving material being delivered to the screed or a rate at which the paving material is being delivered. The paving machine of the present disclosure 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.

SUMMARY

In one aspect, a paving system may include a paving machine and a controller. The paving machine may include a drive assembly, a paving material delivery system, including a hopper, a conveyor assembly, an auger, and a screed assembly, and at least one material sensor configured to monitor a delivery of paving material from the hopper to the auger by the conveyor assembly. The controller may be coupled to the at least one material sensor and the conveyor assembly to control the delivery of paving material from the hopper to a ground surface.

In another aspect, a paving material delivery system may include a hopper, a conveyor assembly, an auger, and at least one material sensor positioned above the conveyor assembly configured to monitor a delivery of paving material from the hopper to the auger.

In a further aspect, a method for delivering paving material may include initiating a paving operation with a paving machine, and monitoring a delivery of paving material, wherein the monitoring the delivery of paving material includes determining a delivery rate with a material sensor positioned above a conveyor assembly that connects a hopper to an auger or a screed assembly. The method may further include comparing the determined delivery rate of the paving material to a desired delivery rate of paving material, and if the determined delivery rate does not match the desired delivery rate, adjusting one or more parameters of the paving operation.

DETAILED DESCRIPTION

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. In this disclosure, relative terms, such as, for example, “about,” “substantially,” and “approximately” are used to indicate a possible variation of ±10% in a stated value. Although the current disclosure is described with reference to a paving machine, this is only exemplary. In general, the current disclosure can be applied as to any machine, such as, for example, a paver finisher, asphalt finisher, or another paving-type machine.

FIG.1illustrates a side view of an exemplary paving machine10, according to the present disclosure. Machine10may be any size paver with any paving width. In one aspect, machine10may be a small paver, for example, with a maximum paving width of approximately 5.5 meters. Alternatively, in another aspect, machine10may be a large paver, for example, with a maximum paving width of approximately11meters. Machine10includes a frame12, a hopper14, an auger16, and a screed18. Machine10may also include an operator station20, from which an operator may maneuver and control machine10. Machine10may be propelled by an engine assembly22to power a drive assembly24, including a drive wheel26, one or more idlers28, and tracks30. Machine10includes a conveyor assembly32to transport paving material through a tunnel33from hopper14to auger16and screed18. Machine10also includes a material sensor34to detect and/or measure an amount of paving material being carried by conveyor assembly32. Additionally, machine10may include one or more control panels36, for example, positioned in operator station20next to steering wheel38, in one or more operator positions40on screed18, remote from machine10, etc. Control panels36may control and/or display information regarding one or more aspects of machine10via a controller102.

Hopper14may be positioned in a forward portion of frame12to receive or store the paving material, for example, from a mixer truck. As shown inFIG.2, hopper14may include side portions14A and14B, which may be controllable to be lifted upward to help direct paving material within hopper14toward conveyor assembly32. Hopper14also includes a rear portion14C, which may help separate hopper14from the engine assembly22and other components of machine10. Moreover, as also shown inFIG.2, hopper14may include a window35formed by an opening in rear portion14C in order for conveyor assembly32to extend and carry paving material into tunnel33. Window35may also limit and/or restrict a height and/or a width of paving material being conveyed by conveyor assembly32in tunnel33. For example, window35includes a height and a width. The width of window35may correspond to the width of conveyor assembly32, or may be wider than the width of conveyor assembly32, as shown inFIG.2. The height of window35may limit a height of paving material conveyed on conveyor assembly32from hopper14.

As mentioned, conveyor assembly32connects hopper14to auger16in a rear portion of machine10to convey the paving material. Conveyor assembly32may extend beneath engine assembly22and operator station20, and may be positioned above drive assembly24. Conveyor assembly32may include at least one conveyor belt42driven by at least one conveyor pulley44. In one example, conveyor assembly32may include two conveyor pulleys44, for example, one in a forward position and one in a rear position. For example, conveyor pulleys44may each rotate in order to drive conveyor belt42to deliver paving material from hopper14to auger16. In another example, conveyor assembly32may include two conveyor belts42, with each conveyor belt42being driven independently by a respective conveyor pulley44. In one aspect, conveyor belt(s)42may travel over one or more plates or supports46, which may help support conveyor belt(s)42. Moreover, as shown inFIG.2, conveyor assembly32may extend from a central position of hopper14.

Although not shown, as mentioned above, conveyor assembly32may include two or more conveyor belts42. The conveyor belts42may extend parallel to one another from hopper14to respective sides of auger16or two respective augers16. The conveyor belts42may be separately controlled and/or driven, or may controlled together or otherwise linked. The speed of the conveyor belt(s)42may be determined based on, for example, a desired delivery rate of paving material to auger16and screed18.

Auger16may be positioned perpendicular to the direction of travel of machine10. Additionally, auger16may include a plurality of parallel or longitudinally arranged auger sections. Auger16may rotate at adjustable rotational speeds, and the rotational speed of auger or the auger sections may be correlated to the speed of conveyor assembly32. Screed18is positioned to the rear of auger16, and smooths the paving material delivered by auger16to the paving surface. The height of screed18may be adjustable, for example, via control panel36. Operator station20may include a plurality of controls in order for an operator to steer machine10, control a rate of delivery of the paving material (e.g., by adjusting a speed of conveyor assembly32by adjusting a rotation speed of conveyor pulley(s)44), adjust the height of screed18, etc.

As shown inFIG.1, sensor34may be positioned above the junction of conveyor assembly32with hopper14. As shown inFIG.2, sensor34may be positioned in a central position of hopper14. For example, sensor34may be positioned at rear end14C of hopper14above window35and/or just forward of where paving material is conveyed from hopper14into tunnel33. Sensor34may be a laser sensor configured to measure a height and/or a cross-sectional area of paving material being carried by conveyor assembly32. For example, sensor34may emit laser energy downward toward conveyor assembly32. A portion of the emitted laser energy may be reflected by the paving material on conveyor assembly32and may be received by sensor34. Sensor34and/or controller102may analyze the received energy to determine a distance between sensor34and the paving material in order to determine a height of the paving material relative to the conveyor assembly32at a position below sensor34. Sensor34and/or controller102may also analyze the received energy to determine a width of the paving material on the conveyor assembly32at the position below senor34. The height of the paving material may change over a width of conveyor assembly32. Nevertheless, sensor34may measure and/or be programmed with the width of conveyor belt(s)42, and may then determine a cross-sectional area of the paving material across the width of conveyor assembly32below sensor34. Sensor34may transmit information regarding the height and/or the cross-sectional area of paving material to controller102. With the instantaneous height and/or cross-sectional area of paving material and the speed of conveyor belt42, controller102may determine a flow rate of paving material on conveyor belt42, and thus a delivery rate of paving material by conveyor assembly32.

In another aspect, sensor34may be a sonic sensor, an optical sensor, or another appropriate sensor to determine the height and/or the cross-sectional area of paving material on conveyor assembly32. As discussed above, in these aspects, sensor34may emit energy toward conveyor assembly32and receive reflected energy to determine a distance between sensor34and the paving material, and thus determine a height of the paving material being transported by conveyor assembly32. Moreover, sensor34may be able to also emit energy toward hopper14and receive reflected energy indicative of one or more heights of paving material within hopper14, and thus an amount of paving material within hopper14. For example, such measurements may be used to help ensure a consistent flow of paving material from hopper14, and/or to provide information regarding the amount of paving material within hopper14(e.g., that a mixer truck is required to add paving material to hopper14). Alternatively, in another aspect, sensor34may be a mechanical level sensor positioned above a portion of conveyor assembly32. In any of the aforementioned aspects, if machine10includes two or more conveyor belts42, machine10may include two or more sensors34, with each sensor34being positioned above the respective conveyor belt42.

As shown inFIG.1, one or more sensors may be positioned in other positions relative to conveyor assembly32. Sensor34′ may be positioned within tunnel33toward the middle of conveyor assembly32, for example, below engine assembly22. Alternatively, sensor34″ may be positioned toward the rear of conveyor assembly32, for example, below operator station20. Furthermore, sensor34″ may be positioned at a rearmost position of conveyor assembly32where conveyor belt42delivers the paving material to auger16. In any of these aspects, sensors34,34′, and34″ may help determine a delivery rate of paving material by conveyor assembly32. Moreover, machine10may include any arrangement of one or more sensors34,34′, and34″, and controller102may receive information from each of the one or more sensors34,34′, and34″ to determine a height, and thus a cross-section, of the paving material on conveyor assembly32. For example, controller102may receive information from sensor34and from sensor34″ to determine whether the cross-sectional area of the paving material changes over a portion of conveyor assembly32.

Referring toFIGS.1and3, one or more control panels36may include or be coupled to (e.g., wired or wirelessly) controller102. As shown inFIG.3, controller102may also be coupled to sensor34, and may also be coupled to one or more sensors and/or to one or more actuators on machine10to form a control system100. For example, machine10may include a conveyor speed sensor104, a screed width sensor106, and a track speed sensor108. Machine10may also include one or more positioning sensors110(e.g., a global positioning system antenna, a LIDAR sensor, a stringline sensor, a total station unit to be detected or otherwise sensed by a universal total station monitor positioned on the worksite, etc.). Machine10may also include a conveyor speed controller112, a screed width controller114, a track speed controller116. Additionally, machine10may include one or more additional actuators or controllers to control the movement of machine10and its components, such as, for example, a steering direction sensor and/or a steering direction controller. Each of the sensors, controllers, and/or actuators may be in communication (e.g., a wired connection or a wireless connection) with each other, for example, through controller102. Moreover, in one aspect, one or more of conveyor speed controller112, screed width controller114, track speed controller116, and any other controllers of machine10may be part of controller102.

Control panel36may be operable to control the delivery of paving material by controlling at least one of a conveyor speed, screed width, and/or track speed, for example, via controller102. In one aspect, control panel36may include a touch screen user interface and/or other displays or input devices.

Conveyor speed sensor104may be coupled to and/or monitor a portion of conveyor assembly32. In one aspect, conveyor speed sensor104may be a rotational speed sensor coupled to or built in with one or more a motor (e.g., a hydraulic motor) that drives one or more conveyor pulleys44. Alternatively or additionally, conveyor speed sensor104may be coupled to and/or monitor conveyor belt42or one or more conveyor pulleys44. Furthermore, in another aspect, conveyor speed sensor104may be configured to determined the speed at which paving material is moving on conveyor belt42. Conveyor speed controller112may be coupled to one or more conveyor pulleys44, for example, to control the rotational rate of one or more conveyor pulleys44. In one aspect, conveyor speed controller112may include a motor coupled to and driving the rotation of one or more conveyor pulleys44in order to rotate the one or more conveyor pulleys44and thus control the movement of conveyor belt42.

Screed width sensor106may be coupled to and/or monitor a portion of screed18and may help determine a width of screed18. In one aspect, although not shown, screed18may include a left screed portion and a right screed portion, which may each be extendable and retractable to control a width of screed18. Screed width sensor106may be coupled to the left and right screed portions in order to determine an extension or retraction of each of the left and right screed portions to determine an overall width of screed18. Screed width controller114may also be coupled to screed18, for example, to the left and right screed portions. Screed width controller114may include one or more drive assemblies or actuators (e.g., hydraulic cylinders) configured to adjust the width of screed18, for example, by controlling the lateral extension or retraction of one or more of the left and right screed portions.

Track speed sensor108may be coupled to and/or monitor one or more portions of drive assembly24and may help determine a ground speed of machine10. In one aspect, track speed sensor108may be coupled to and/or monitor one or more of drive wheel26, idlers28, and/or tracks30. Track speed controller116may also be coupled to a portion of drive assembly24, for example, to drive wheel26. Track speed controller116may be coupled to and control a motor coupled to and driving the rotation of drive wheel26in order to rotate drive wheel26and thus control the movement of track30.

Conveyor speed sensor104and conveyor speed controller112are coupled to controller102in order to determine and control a speed of conveyor belt42. Screed width sensor106and speed width controller114are coupled to controller102in order to determine and control a width of screed18. Track speed sensor108and track speed controller116are coupled to controller102in order to determine and control a speed of track30, and thus help determine and control a ground speed of machine10.

As mentioned above, machine10may include position sensor110. Position sensor110may help to determine a position of machine10on a worksite and/or relative to other machines and/or topographical features. Position sensor110may also help to determine an overall ground speed for machine10.

Although not shown, controller102may be in communication with additional sensors mounted to or within machine10, for example, an odometer, a speedometer, temperature sensors, etc. Moreover, controller102may be in communication with additional displays or operator stations, for example, a central control station for the worksite, an electronic log or memory that stores operating instructions and/or records the positions and other operational aspects of machine10over a worksite, etc.

FIG.4is a flow diagram portraying an exemplary paving method400that may be performed by control system100to monitor and/or control the delivery of paving material by machine10. Method400includes a step402, in which machine10may initiate a paving operation. Step402may include controller102signaling one or more of conveyor speed controller112, screed width controller114, and/or track speed controller116. For example, controller112may signal conveyor speed controller112to activate conveyor pulley44to move conveyor belt42. Furthermore, controller112may signal screed width controller114to set a width of screed18, and controller112may signal track speed controller116to power drive wheel26to move track30.

Method400includes a step404, where controller102monitors the delivery of paving material, for example, via sensor34. Controller102may also be in communication with one or more of conveyor speed sensor104, screed width sensor106, track speed sensor108, and/or position sensor110. Controller102may determine a rate of delivery of paving material to the ground surface. For example, based on the height and/or the cross-sectional area of paving material as measured by sensor34and the speed of conveyor belt42, controller102may determine a rate at which the paving material is being delivered from hopper14to auger16. In one aspect, controller102may determined a volume of material being delivered by multiplying the cross-section of the material on conveyor belt42(from sensor34) by the speed of the conveyor belt42. For example:
Material Volume=(Material Cross-Section)×(Speed of Conveyor Belt)

Based on the speed of tracks30(and thus the speed of machine10), controller102may also determine a rate at which the paving material is being delivered to the ground surface. Furthermore, based on the width of screed18, controller102may determine a thickness of the paving material that has been delivered to the ground surface and spread by screed18. For example, controller102may determine a paving thickness by dividing the determined material volume by the product of the paving width (from screed width sensor106) and the paving distance (from track speed sensor108and/or position sensor110). For example:
Paving Thickness=(Material Volume)/((Paving Width)×(Paving Distance))

Method400also includes a step406, in which controller102compares the determined rate of delivery of paving material to a desired rate of delivery of paving material to determine whether the determined rate of delivery matches (or is within an acceptable range relative to) the desired rate of delivery. The desired rate of delivery of paving material may be a user-input rate of delivery (e.g., cubic meters of paving material per minute, cubic meters of paving material per paved meter, etc.). Alternatively, the desired rate of delivery may be a pre-programmed rate of delivery specific to machine10, a type of paving operation, etc.

If the determined rate of delivery of paving material matches the desired rate of delivery of paving material, controller102may signal one or more of conveyor speed controller112, screed width controller114, and/or track speed controller116to maintain the existing parameters in a step408. Method400may then return to step404.

If, however, the determined rate of delivery of paving material does not match the desired rate of delivered of paving material, method400may include a step410, in which controller102transmits a signal to adjust one or more parameters of the paving operation. For example, step410may include controller102transmitting a signal to one or more of conveyor speed controller112, screed width controller114, and/or track speed controller116to adjust the existing parameters before returning to step404.

It is noted that the desired rate of delivery of paving material may be input and/or monitored in a variety of ways. For example, the desired rate of delivery of paving material may be measured as a volume of paving material being conveyed by conveyor belt42, and thus delivered to auger16, as a function of time. Alternatively, the desired rate of delivery of paving material may be measured in a volume of paving material being spread by screed18as a function of paving area. Moreover, an operator may desire to know how many tons of paving material are currently being delivered or have been delivered per hour by machine10. In another aspect, an operator may desire to know how many tons of paving material are currently being delivered or have been delivered per mile of paving. If the measured rate differs from the desired rate, controller102may signal one or more adjustments. For example, if the amount of paving material being conveyed by conveyor belt42is below the desired amount, controller102may signal conveyor speed controller112to accelerate conveyor pulley44to drive conveyor belt42at a faster speed. Similarly, an acceleration of conveyor belt42may also result in auger16rotating at a faster rate. Alternatively or additionally, controller102may signal track speed controller116to decelerate drive wheel26to drive track30(and thus machine10) at a lower speed.

Moreover, in one aspect, step410may include alerting the operator to the determined rate of delivery of paving material and/or whether the determined rate of delivery of paving material matches the desired rate of delivery of paving material. For example, the determined rate of delivery and the desired rate of delivery may both be displayed on a screen of control panel36. Alternatively or additionally, if the determined rate of delivery and the desired rate of delivery do not match, an alert or alarm may be displayed on the screen of control panel36, audibly sounded, or otherwise activated to alert the operator to the difference between the determined rate of delivery and the desired rate of delivery, and thus the need to adjust one or more parameters for machine10. The one or more parameters may be adjusted automatically or may be manually adjusted by the operator (e.g., via control panel36).

The above steps of method400may be periodically performed during a paving operation (e.g., every 10 minutes, every 30 minutes, every hour, every 50 meters, every 100 meters, every 200 meters etc.), or may be constantly performed during the paving operation. Moreover, the results of step406may be displayed on control panel36, another display, a user interface, etc.

Industrial Applicability

The disclosed aspects of machine10may be used in any paving machine to assist in delivery of paving material. During operation, conveyor assembly32may deliver paving material to the ground surface traversed by machine10, for example, from hopper14to auger16and screed18. Sensor34may help to monitor the delivery of the paving material to the ground surface, which may help to ensure that the proper amount of paving material is being delivered and spread on the ground surface. As mentioned, sensor34may be a laser, sonic, optical, or mechanical sensor that may measure a height of a pile of paving material on conveyor assembly32. Sensor34may determine a width of the paving material. Alternatively or additionally, a width of conveyor belt42may be known. In one aspect, when hopper14is completely full (e.g., with paving material filling hopper14and abutting rear end14C, sensor34positioned above window35may be able to measure a height of the paving material in hopper14, but may not be able to measure a height of the paving material on conveyor belt42. In such an instance, controller102may use the known height of window35to approximate the height of the paving material on conveyor belt42. Nevertheless, sensor34′ and/or sensor34″, with their positions within tunnel33, may determine a height of the paving material on conveyor belt42within tunnel33. With the height and width of the paving material, along with the speed of conveyor belt42, controller102may determine an instantaneous flow rate of paving material being conveyed by conveyor assembly32.

With the speed of machine10via track speed sensor108and/or position sensor110, controller102may determine a rate at which the paving material is being delivered to the ground surface. Moreover, with the width of screed18via screed width sensor106, controller102may determine a rate at which the paving material is being spread on the ground surface. Controller102may then compare one or more of the flow rate on conveyor assembly32, the delivery rate to the ground surface, and/or the spread rate on the ground surface to respective desired rates. Accordingly, if necessary, controller102may signal one or more of conveyor speed controller112, screed width controller114, and track speed controller116to adjust the respective parameters (e.g., speed up or slow down conveyor belt42, extend or retract screed18, or speed up or slow down track30). Controller102may signal the operator (e.g., via control panel36) to make the appropriate adjustments, or controller102may automatically signal one or more of the controllers to make the appropriate adjustments.

With the aforementioned monitoring steps and measuring a duration of the paving operation, the systems and methods discussed herein may track the amount of paving material being delivered during the paving operation. For example, controller102may track and/or display (e.g., on control panel36) a volume of paving material that is currently being delivered (e.g., instantaneously), a volume of paving material that has been delivered over a period of time (e.g., the last hour), and/or a volume of paving material that has been delivered over the entirety of the paving operation. Such information may be helpful to analyze the effectiveness, efficiency, cost, quality, and/or other parameters of the paving operation.

Moreover, in one aspect, a paving operation may begin with a known amount of paving material in hopper14. Then, based on height of paving material removed from hopper14by conveyor assembly32, the speed of conveyor belt42, and the elapsed duration of the paving operation, controller102may signal to the operator (e.g., via control panel36), that the amount of paving material in hopper14is running low. Controller102may signal that a mixer truck is required to add paving material to hopper14.

The disclosed aspects of machine10also allow a user to monitor and adjust the various elements of machine10, including those elements that deliver paving material, from either a position on machine10or from a remote position. For example, a user may monitor and adjust the conveyor speed, the screed width, and/or the machine speed via control panel36. If, for example, machine10begins to pave at a lower speed, then the user may decrease the speed of conveyor belt42, increase the width of screed18, etc. to help avoid delivering too much paving material to the ground surface. In an additional aspect, a user may pre-program a correlation between the speed of tracks30, width of screed18, and the speed of conveyor belt42to be implemented by controller102in order to help ensure the delivery of an appropriate amount of paving material to the ground surface.