MONITORING INSULATION RESISTANCE OF A SCREED ASSEMBLY OF A PAVING MACHINE

A method may include determining, by a controller of a paving machine, to start a test of one or more heaters associated with a screed assembly of the paving machine. The method may further include sending, by the controller and to a tester device associated with the paving machine, one or more signals configured to cause a test voltage to be generated while the one or more heaters are sequentially turned off and then on during the test. The method may further include receiving, by the controller, a measurement of an insulation resistance of each of the one or more heaters during the test. The method may further include performing, by the controller, one or more actions based on a result of processing the measurement.

TECHNICAL FIELD

The present disclosure relates generally to monitoring a screed assembly of a paving machine, and more particularly, to monitoring insulation resistance of the screed.

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 machines generally include a screed assembly for spreading and compacting a mat of paving material relatively evenly over a desired surface. During paving, screed plates in the screed assembly are heated to prevent asphalt from sticking to the screed plates as the asphalt is compacted. As such, during paving operations, it is important to try to identify heaters on the screed assembly that are faulty or likely to experience a fault.

EP Patent No. 3051024B1, granted on Nov. 21, 2018 (“the '024 patent”), describes a method for monitoring a plank heater of a road finishing machine. In particular, the '024 patent describes switching off all heating sections with the exception of the heating section on which a different temperature is measured. For the heating section that is kept on, the method then turns off all but a few heating elements. If the heating elements operate correctly, an operator can determine that the malfunction is located at a different location. However, by requiring that all but a faulty heating section, or all but a few heating elements of the heating section, be turned off, the method of the '024 patent cannot identify and isolate faults during operation of a paving machine.

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 method may include determining, by a controller of a paving machine, to start a test of one or more heaters associated with a screed assembly of the paving machine. The method may further include sending, by the controller and to a tester device associated with the paving machine, one or more signals configured to cause a test voltage to be generated while the one or more heaters are sequentially turned off and then on during the test. The method may further include receiving, by the controller, a measurement of an insulation resistance of each of the one or more heaters during the test. The method may further include performing, by the controller, one or more actions based on a result of processing the measurement.

In another aspect, a paving machine may include a screed assembly, one or more heaters associated with the screed assembly, a tester device, and a controller. The controller may be configured to determine to start a test of one or more heaters associated with the screed assembly of the paving machine. The controller may be further configured to send, to the tester device associated with the paving machine, one or more signals configured to cause a test voltage to be generated while the one or more heaters are sequentially turned off and then on during the test. The controller may be further configured to receive a measurement of an insulation resistance of each of the one or more heaters during the test. The method may be further configured to perform one or more actions based on a result of processing the measurement.

In yet another aspect, a controller for a paving machine may be configured to determine to start a test of one or more heaters associated with a screed assembly of the paving machine. The controller may be further configured to send, to a tester device associated with the paving machine, one or more signals configured to cause a test voltage to be generated while the one or more heaters are sequentially turned off and then on during the test. The controller may be further configured to receive a measurement of an insulation resistance of each of the one or more heaters during the test. The controller may be further configured to perform one or more actions based on a result of processing the measurement.

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. 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 assembly.

FIG.1is a schematic view of an exemplary paving machine10that includes a screed assembly12and elements for monitoring the screed assembly12, according to aspects of the disclosure. The paving machine10may deposit or pave a mat44on a base46. The paving machine10may include a screed assembly12and a pair of tow arms30(only one of which is visible inFIG.1) attached to the screed assembly12and tow points50located on a frame of the paving machine10, as shown inFIG.1. The tow arms30may be attached to a pair of tow point cylinders52(only one of which is visible inFIG.1). The tow point cylinders52may be configured to control the height of the tow points50by adjusting hydraulic pressures within the tow point cylinders52, thereby controlling the height of the tow arms30. The paving machine10may further include a hopper38adapted for storing a paving material such as asphalt, and a conveyor system including one or more conveyors40configured for moving the paving material from the hopper38to the screed assembly12to a rear of the paving machine10. One or more augers36may be arranged near a forward end of the screed assembly12to receive the paving material provided by the conveyor40and spread the paving material evenly beneath the screed assembly12. The paving machine10may also include an inclinometer42attached to the frame of the paving machine10, as shown inFIG.1. The inclinometer42may measure the angle at which the paving machine10travels on the base46(e.g., a ground surface). Additionally, the paving machine10may include a display48for providing visual feedback of operation controls and/or conditions of the paving machine10.

As further shown inFIG.1, the screed assembly12may be pivotally connected (at the tow point50) behind the paving machine10by the tow arms30. The tow arms30may be configured to float so as to be raised and lowered as a function of the amount of paving material at an upstream end of the screed assembly12. The relative position and orientation of the screed assembly12relative to the frame of the paving machine10and the mat44may be adjusted by adjusting the tow point50connected to the pivoting tow arms30, in order, for example, to control the thickness of the paving material deposited via the paving machine10and to adjust the angle of attack of the screed assembly12. The screed assembly12may include a main screed14and screed extenders16(only one of which is illustrated inFIG.1). The screed extenders16may be configured, by a screed extender control32, to be slidably movable laterally relative to the main screed14between retracted and extended positions so that varying widths of paving material can be laid. The screed extenders16may include an extender screed plate18.

The main screed14may include a main screed plate20, a tamper bar22, a deflector28, and a pre-strikeoff26. The tamper bar22may be connected to a tamper bar controller24that is configured to move the tamper bar22up and down so as to be able to strike the surface of the paving material after it is deposited by one or more augers36. The tamper bar22may provide compaction of the paving material as well as affecting the angle of attack of the screed assembly12. The pre-strikeoff26may be attached (e.g., by welding) to the deflector28. The height of the pre-strikeoff26, which may affect the angle of attack of the screed assembly12, may be adjustable vertically by moving the deflector28vertically up and down. The main screed14may also include the inclinometers34(only one of which is shown inFIG.1) in order to measure the angle of attack of the screed assembly12relative to the mat44, and the cross slope or twist angle of the main screed14.

The paving machine10may include a controller54. Controller54may include a processor and a memory (the processor and memory are not shown inFIG.1). The processor may include a central processing unit (CPU), a graphics processing unit (GPU), a microprocessor, a digital signal processor and/or other processing units or components. Additionally, or alternatively, the functionality described herein can be performed, at least in part, by one or more hardware logic components. For example, and without limitation, illustrative types of hardware logic components that may be used include field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), system-on-a-chip systems (SOCs), complex programmable logic devices (CPLDs), etc. Additionally, the processor may possess its own local memory, which also may store program modules, program data, and/or one or more operating systems. The processor may include one or more cores.

The memory may be a non-transitory computer-readable medium that may include volatile and/or nonvolatile memory, removable and/or non-removable media implemented in any method or technology for storage of information, such as computer-readable instructions, data structures, program modules, or other data. Such memory includes, but is not limited to, random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disc read-only memory (CD-ROM), digital versatile discs (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, redundant array of independent disks (RAID) storage systems, or any other medium which can be used to store the desired information and which can be accessed by a computing device (e.g., the display48, a server device remote to the paving machine10, etc.). The memory may be implemented as computer-readable storage media (CRSM), which may be any available physical media accessible by the processor to execute instructions stored on the memory. The memory may have an operating system (OS) and/or a variety of suitable applications stored thereon. The OS, when executed by the processor, may enable management of hardware and/or software resources of the controller54.

The memory may be capable of storing various computer readable instructions for performing certain operations described herein. The instructions, when executed by the processor, may cause certain operations described herein to be performed.

As further illustrated inFIG.1, the paving machine10may include one or more heaters56. For example, the screed assembly12may include one or more zones, and each of the zones may have one or more associated heaters56for heating screed plates18,20in the zones. The controller54and/or a tester device60may test one or more of the heaters56during operation of the paving machine10, as described in more detail elsewhere herein. One or more power modules58may provide electrical power to the heaters56, and the controller54and/or tester device60may control the power modules58.

The tester device60may include a processor and memory, similar to that described with respect to the controller54. The tester device60may, based on a command from the controller54, execute instructions or testing sequences to test the one or more heaters56. For example, and as described herein, the tester device60may sequentially turn off and then on the heaters56while generating a test voltage, and may measure an insulation resistance of the heaters56.

FIG.2is a diagram illustrating an exemplary system architecture for monitoring insulation resistance of the screed assembly12of the paving machine10, according to aspects of the disclosure. As illustrated inFIG.2, the system architecture may include a generator/inverter62(e.g., a generator, an inverter, or a combined generator and inverter). The generator/inverter62may convert mechanical energy to electrical energy (in the case of a generator) and/or may convert electrical energy from one form into another in the case of an inverter (e.g., converts direct current to alternating current). The generator/inverter62may output electrical energy to the screed power module58. The power module58may control supply of electrical energy to one or more heating zones68.FIG.2illustrates a detailed view of a first heating zone68(zone1), andFIG.2illustrates that the system architecture may include one or more other heating zones68(zone2to zone N).

The first heating zone68may include a junction box64(e.g., a “zone1junction box” for the first zone68). The junction box64may include circuitry to electrically connect one or more elements of the heating zone68to one or more other elements of the paving machine10. The heating zone68may further include a relay or contactor66that includes circuitry that electrically connects a heater56in the zone1(heater56-1) to the junction box64and the tester device60. In particular, the relay or contactor66may include switching circuitry that selectively connects the heater56-1to the junction box64or to the tester device60, depending on output70(e.g., commands) from the controller54to close the relay or contactor66. For example, the relay or contactor66may switch a common electrical connection (labeled “common” inFIG.2) from a normally closed (“N/C”) connection to the junction box64to a normally open (“N/O”) connection to the tester device60.

When the common electrical connection is switched to the N/O electrical connection, the tester device60may perform a test of the heater56-1, as described in more detail elsewhere herein. The tester device60may further include electrical connections to provide output72to the controller54for fault monitoring and/or for taking actions.

INDUSTRIAL APPLICABILITY

The disclosed aspects of the controller54, the tester device60, and/or a remote server device of the present disclosure, and in particular, the methods executed by the controller54, the tester device60, and/or the server device may be used to monitor insulation resistance of a screed assembly12of a paving machine10. For example, the methods executed by the controller54, the tester device60, and/or the server device may control when the tester device60performs a test of one or more heaters56, may control a manner in which the tester device60performs the test, may process results of the test to identify faulty heaters56or heaters56that are at risk of experiencing faults, may perform one or more actions to protect the paving machine10from damage as a result of the detected faults (or potential faults), and/or the like. Thus, certain embodiments described herein may provide various advantages to the operation of a paving machine10, such as fault reduction, damage prevention, and/or the like, which may reduce downtime of the paving machine10, may reduce or eliminate disruptions to operations at a worksite that might otherwise occur as a result of unexpected faults of the paving machine10, and/or the like. In addition, certain embodiments described herein may perform certain operations while the paving machine10is in use, or when the paving machine10is started, which may increase an efficiency of using the paving machine10by reducing or eliminating a need for the paving machine10to be pulled out of service for testing. Additionally, or alternatively, certain embodiments described herein may be capable of measuring the insulation resistance of each heater56in real time, which may reduce a response time for taking a corrective or preventative action after detecting a fault or potential fault.

FIG.3illustrates a flowchart depicting an exemplary method100for monitoring insulation resistance of a screed assembly12of a paving machine10. The method100illustrated inFIG.3may be implemented by the controller54. In some embodiments, one or more steps of the method100may be performed by the tester device60and/or by a server device remote to the paving machine10(e.g., a server device located at a control center for a work site, located in a data center, and/or the like). The steps of the method100described herein may be embodied as machine readable and executable software instructions, software code, or executable computer programs stored in the memory and executed by the processor of the controller54(or of the tester device60or the server device). The software instructions may be further embodied in one or more routines, subroutines, or modules and may utilize various auxiliary libraries and input/output functions to communicate with other equipment. The method100illustrated inFIG.3may also be associated with an operator interface (e.g., a human-machine interface, such as a graphical user interface (GUI)) through which an operator of the paving machine10or a worksite may control the paving machine10, may configure a test of a heater56, and/or the like. Therefore, the method100may be implemented by the controller54(or the tester device60or the server device) to monitor insulation resistance of the screed assembly12of the paving machine10, for example.

At step102, the method100may include determining to start a test of one or more heaters56associated with a screed assembly12of a paving machine10. For example, the controller54may determine to start the test based on input from an operator of the paving machine10(e.g., input provided via the display48), based on start-up of the paving machine10(or boot-up of a system, such as a diagnostic system, of the paving machine10), based on receiving a command from a remote control center via a wireless network, and/or the like. Additionally, or alternatively, the controller54may determine to start the test at a predetermined or scheduled time based on a configuration stored by the controller54or based on information included in a command to start the test.

In some embodiments, the controller54may determine the test to be performed. For example, the controller54may determine a subset of one or more available tests to be performed based on an age, number, configuration, hours of usage, and/or the like of the heaters56. Continuing with the previous example, the controller54may select a test that tests each heater56more frequently than another test that just tests the heaters56on start-up of the paving machine10based on the heaters56being older than a certain age. Additionally, or alternatively, the controller54may determine certain heaters56for which a test is to be performed based on characteristics of the heaters56. For example, the controller54may select one or more heaters56for testing by selecting heaters56that have a similar age, hours of usage, and/or the like. In some embodiments, the tester device60, rather than the controller54, may perform these determinations. These aspects may help to improve detection and/or prediction of a faulty heater56.

In some embodiments, the controller54may receive a configuration of a test from an operator of the paving machine10via the display48or a server device via a wireless network, and the controller54may configure the tester device60to perform the test. For example, the controller54may send a message to the tester device60to configure the tester device60. Alternatively, the tester device60may receive a configuration of the test directly from the off-board server device or the configuration may be pre-loaded on the tester device60during fabrication of the paving machine10.

The method100may further include, at step104, sending, to a tester device60associated with the paving machine10, one or more signals configured to cause a test voltage to be generated while the one or more heaters56are sequentially turned off and then on during the test. For example, the controller54may send one or more commands to the tester device60to perform a test for certain heaters56, to perform the test at a certain time, configurations for the test, and/or the like. A test may include testing one heater56at a time by turning off a first heater56(e.g., switching the relay or contactor66from an N/C connection to a N/O connection), generating a test voltage, measuring the insulation resistance of the heater56, and then turning the first heater56on (e.g., switching the relay or contactor66from the N/O connection to the N/C connection) before testing one or more other heaters56. By sequentially testing each heater56while other heaters56are on, certain embodiments may monitor the screed assembly12while the paving machine10is in operation and may help to precisely identify which heaters56are faulty.

At the scheduled time of the test, the controller54may send one or more signals to the relay or contactor66to switch an electrical connection from a junction box64to the tester device60. Alternatively, the tester device60may send the one or more signals to the relay or contactor66.

Upon receipt of the one or more signals, the tester device60may perform the test according to the configuration described above. For example, the tester device60may turn off a heater56under testing, generate a test voltage on an electrical connection with the heater56, may measure the insulation resistance of the heater56, and may then turn the heater56on. To measure the insulation resistance, the tester device60may measure current leakage using one or more sensors associated with the heater56. During the test, the tester device60may store the measurements in memory.

At step106, the method100may include receiving a measurement of an insulation resistance of the each of the one or more heaters during the test. For example, the controller54may receive the measurement from the tester device60for processing or for providing to an off-board server device for processing. The measurement received may include a stream of measurements from the tester device60or may receive measurements that have been pre-processed by the tester device60. For example, the pre-processing may include the tester device60aggregating measurements over time or eliminating outlier measurements. In some embodiments, the controller54may receive un-processed data from the tester device60and may perform the pre-processing before sending the measurements to the off-board server device for further processing.

Upon receiving the measurement or after performing pre-processing, the controller54may process the measurements to detect a fault in the insulation resistance or to predict a fault in the insulation resistance. For example, this processing may include generating a degradation curve for the measurements for each heater56and may monitor whether the degradation curve falls below a threshold. Alternatively, the tester device60and/or the controller54may provide the measurements to an off-board server device (e.g., via a wireless network) to perform this processing. In this case, the off-board server device may provide a result of the processing to the controller54and/or tester device60, may just provide alerts when the degradation curve falls below the threshold, and/or the like. Alternatively, the tester device60may process the measurements upon gathering the measurements from a sensor and may provide a result (or alerts based on the result) to the controller54, rather than the controller54or the off-board server device performing the processing. In some embodiments, the controller54, the tester device60, and/or the off-board server device may provide the measurements, or a result of processing the measurements, for display via the display48.

The method100may further include, at step108, performing one or more actions based on a result of processing the measurement. For example, the controller54may perform the one or more actions based on a result of the processing indicating that the measurement has fallen below a threshold (e.g., a threshold indicating a fault in the insulation resistance or a threshold indicating that a fault is likely to occur within a certain amount of time), that the trend line for the measurement has a particular shape or slope, and/or the like. In some embodiments, the tester device60and/or an off-board server device may perform the one or more actions.

The one or more actions may include shutting down the paging machine10, a heater56, and/or a zone68of the screed assembly12when the measurement falls below a threshold. For example, the controller54may trip a ground fault. Additionally, or alternatively, the one or more actions may include modifying an operation of the paving machine10. For example, if a heater56, or a certain number of heaters56, have faults, the controller54may send a command to raise the screed assembly12or adjust a position of the screed assembly12. As another example, the controller54may send a command to power on one or more auxiliary heaters56or to increase the temperature of one or more heaters56adjacent to a faulty heater56.

Additionally, or alternatively, the one or more actions may include providing an alert, alarm, or message for display via the display48when the measurement falls below a threshold. Similarly, the one or more actions may include providing, for display via the display48, information that indicates a status of the insulation resistance (e.g., a high, medium, or low status), and updating the information in real-time or near real-time based on the result of the measurement.

Additionally, or alternatively, the one or more actions may include scheduling the paving machine10for maintenance. For example, the controller54and/or the off-board server device may access an electronic schedule for a maintenance facility and may generate a reservation on the schedule for maintenance of the paving machine10. Additionally, or alternatively, the one or more actions may include sending a message to a device associated with a technician to perform maintenance or inspection of one or more heaters56.

Although the method100illustrated inFIG.3is described as including steps102to108, the method100may not include all of these steps or may include additional or different steps. For example, the method100may just include the steps106and108.

Certain embodiments described herein may provide, for example, real-time or near real-time monitoring of an insulation resistance of a heater56, which may reduce or eliminate damage to asphalt or a paving machine10that might occur as a result of latency in identifying faulty heaters. Similarly, certain embodiments may provide for early detection of a fault that is likely to occur, which may reduce interruptions to operations of the paving machine10and/or at a worksite. As another example, certain embodiments may provide for monitoring of the insulation resistance while the paving machine10is operating or upon start-up of the paving machine10, which may reduce or eliminate a need to take the paving machine10to a maintenance facility for testing of the heaters56. This may reduce downtime of the paving machine10for maintenance, may reduce the amount of time that the paving machine10needs to spend at a maintenance facility, and/or the like through accurate identification of a faulty heater56and/or by eliminating in-facility maintenance.