US20160265174A1

US20160265174A1 - Control system having obstacle detection and mapping

Info

Publication number: US20160265174A1
Application number: US14/641,989
Authority: US
Inventors: Eric S. Engelmann; Mario J. Souraty; Conwell K. Rife, Jr.
Original assignee: Caterpillar Paving Products Inc
Current assignee: Caterpillar Paving Products Inc
Priority date: 2015-03-09
Filing date: 2015-03-09
Publication date: 2016-09-15
Also published as: DE102016002700A1

Abstract

A control system is disclosed for use with a cold planer having a milling drum. The control system may have an obstacle detection sensor mountable to the cold planer at a location forward of the milling drum. The obstacle detection sensor may be configured to generate a first signal indicative of an object detected within a work surface. The control system may also have a locating device mountable to the cold planer and configured to generate a second signal indicative of a location of the cold planer at a time of first signal generation, and a controller in communication with the obstacle detection sensor and the locating device. The cold planer may be configured to generate an electronic map of a work area based on the first and second signals, and to selectively adjust operation of the cold planer based on the electronic map.

Description

TECHNICAL FIELD

The present disclosure relates generally to a control system for a cold planer and, more particularly, to a cold planer control system having obstacle detection and mapping functionality.

BACKGROUND

Asphalt-surfaced roadways are built to facilitate vehicular travel. Depending upon usage density, base conditions, temperature variation, moisture levels, and/or physical age, the surfaces of the roadways eventually become misshapen and unable to support wheel loads. In order to rehabilitate the roadways for continued vehicular use, spent asphalt is removed in preparation for resurfacing.
Cold planers, sometimes also called road mills or scarifiers, are used to break up and remove layers of an asphalt roadway. A cold planer typically includes a frame propelled by tracked or wheeled drive units. The frame supports an engine, an operator's station, a milling drum, and conveyors. The milling drum, fitted with cutting tools, is rotated through a suitable interface with the engine to break up the surface of the roadway. The broken up roadway material is deposited by the milling drum onto the conveyors for removal from the machine.
It may be possible, in some situations, for hard objects to be located within the asphalt material being reclaimed by the cold planer. When the cutting tools of the milling drum engage these objects, the cutting tools can he quickly dulled or broken. In some situations, the objects may be difficult to see and avoid, or even hidden below the surface of the asphalt material.
One attempt to increase longevity of a cold planer is disclosed in U.S. Patent Application No. 2014/0348584 of Fritz et al. that published on Nov. 27, 2014 (“the '584 publication”). In particular, the '584 publication discloses a milling machine having a drum supported from a frame. The '584 publication also discloses a detection system configured to determine a location of the drum in an external reference system, a location indicator system configured to store location information of an. area to be avoided, and a controller configured to compare the drum location to the avoidance area location. Based on the comparison, the controller provides output corresponding to the proximity of the drum to the avoidance area. The output includes a warning provided to an operator of the milling machine, and/or automated control (e.g., stopping or drum raising) of the milling machine.
The location indicator system of the '584 publication is provided with object location information from a field rover. The field rover is moved to the location of a known object, and an operator of the rover inputs corner points, outlines, and clearances associated with the object. This information is then uploaded to the location indicator system for use in comparison with the drum location.
While effective in some applications, the milling machine of the '584 publication may be less than optimal. Specifically, there may be situations where the location of the object is unknown and/or the object is at least partially buried within the asphalt. In these situations, the field rover may not be able to generate the object information required by the milling machine for proper avoidance of the object.
The control system of the present disclosure solves one or more of the problems set forth above and/or other problems in the art.

SUMMARY

In one aspect, the present disclosure is related to a control system for a cold planer having a milling drum. The control system may include an obstacle detection sensor mountable to the cold planer at a location forward of the milling drum. The obstacle detection sensor may be configured to generate a first signal indicative of an object detected within a work surface. The control system may also include a locating device mountable to the cold planer and configured to generate a second signal indicative of a location of the cold planer at a time of first signal generation, and a controller in communication with the obstacle detection sensor and the locating device. The controller may be configured to generate an electronic map of a work area based on the first and second signals, and to automatically. adjust operation of the cold planer based on the electronic map.
In another aspect, the present disclosure is related to a method of operating a cold planer having a milling drum. The method may include detecting an object in a work surface being milled by the milling drum, and determining a location of the cold planer when the object is detected. The method may further include generating an electronic map of a work area based on detection of the object and the location of the cold planer, and automatically adjusting operation of the cold planer based on the electronic map.
In yet another aspect, the present disclosure is directed to a cold planer. The cold planer may include a frame, a traction device connected to the frame and configured to propel the cold planer, and an engine mounted to the frame and configured to drive the traction device. The cold planer may also include a milling drum connected to the frame, a first actuator associated with the traction device and configured to affect at least one of a speed of the traction device and a depth of the milling drum, and a second actuator associated with the milling drum and configured to affect at least one of a rotational speed of the milling drum and the depth of the milling drum. The cold planer may further include an operator station supported by the frame at a side opposite the milling drum, a display disposed in the operator station, an obstacle detection sensor mounted forward of the milling drum, and a locating device. The obstacle detection sensor may be configured to generate a first signal indicative of an object detected within a work surface. The locating device may be configured to generate a second signal indicative of a location of the cold planer at a time of first signal generation. The cold planer may additionally include a controller in communication with the obstacle detection sensor, the locating device, the display, and at least one of the first and second actuators. The controller may be configured to generate an electronic map of a work area based on the first and second signals, and to show the electronic map on the display. The controller may also be configured to automatically adjust operation of the at least one of the first and second actuators based on the electronic map.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cutaway view illustration of an exemplary disclosed cold planer; and

FIG. 2 is a diagrammatic illustration of an exemplary disclosed control system that may be used in conjunction. with the cold planer of FIG. 1.

DETAILED DESCRIPTION

For the purpose of this disclosure, the term “asphalt” is defined as a mixture of aggregate and asphalt cement. Asphalt cement is a brownish-black solid or semi-solid mixture of bitumens obtained as a byproduct of petroleum distillation. The asphalt cement can be heated and mixed with the aggregate for use in paving roadway surfaces, where the mixture hardens upon cooling. A “cold planer” is defined as a machine used to remove layers of hardened asphalt from an existing roadway. It is contemplated that the disclosed cold planer may also or alternatively be used to remove cement and other roadway surfaces, or to remove non-roadway surface material such as in a mining operation.
FIG. 1 illustrates an exemplary cold planer 10 having a frame 14 supported by one or more traction devices 16, a milling drum 12 rotationally supported under a belly of frame 14, and an engine 18 mounted to frame 14 and configured to drive milling drum 12 and traction devices 16. Traction devices 16 may include either wheels or tracks connected to actuators 19 that are adapted to controllably raise and lower frame 14 relative to a ground surface. It should be noted that, in the disclosed embodiment, raising and lowering of frame 14 may also function to vary a penetration depth of milling drum 12 into the ground surface. In some embodiments, the same or different actuators 19 may also be used to steer cold planer 10 and or to adjust a travel speed of traction devices 16 (e.g., to speed up or brake traction devices 16), if desired. One or more additional actuators 20 may be associated with milling drum 12 and configured to adjust a rotational speed and/or the depth of milling drum 12 independent of, or in conjunction with, actuators 19. A conveyor system 22 may be connected at a leading end to frame 14 and configured to transport material away from milling drum 12 and into a waiting haul vehicle 24.
Frame 14 may also support an operator station. 26 at a side opposite milling drum 12. Operator station 26 may house any number of interface devices 28 used to control cold planer 10. In the disclosed example, interface devices 28 include, among other things, a display 28 a, a warning device 28 b, and an input device 28 c (28 a-c shown only in FIG. 2). Display 28 a may be configured to render the location of cold planer 10 (e.g., of milling drum 12) relative to objects 30 found within the surface being milled. Warning device 28 b may be configured to audibly and/or visually alert the operator of cold planer 10 as to a proximity of milling drum 12 to objects 30. Input device 28 c may be configured to receive control instructions from the operator of cold planer 10. Other interface devices (e.g., control devices) may also be possible, and one or more of the interface devices described above could be combined into a single interface device, if desired.
An object detection device (“device”) 32 may be mounted to cold planer 10 at a location forward of milling drum 12, relative to a normal cutting or working direction. Device 32 may be any type of device known in the art for detecting a location of objects 30. In some embodiments, only a 2-D location may be detected. In other embodiments, a depth of objects 30 within the roadway surface may also be detected by device 32. For example, device 32 may be a magnetic field detector having any number of detection sensors (e.g., magnetometers) 34 arranged across a width of cold planer 10. In another example, device 32 may be a ground penetrating radar having any number of detection sensors (e.g., radar receivers) 34. As will be explained in more detail below, signals generated by sensors 34 may be used to automatically adjust operation (e.g., travel speed, rotational speed, milling depth, etc.) of cold planer 10. Although shown as being connected to conveyor system 22, it is contemplated that device 32 could alternatively he connected closer to milling drum 12, for example to a front cover of a drum enclosure or to frame 14, if desired.
As illustrated in FIG. 2, a control system 36 may be associated with cold planer 10 and include elements that cooperate to map the work area around cold planer 10 and to implement the automatic adjustments discussed above based on the mapping. These elements may include actuator 19, actuator 20, interface devices 28, sensors 34, a locating device 38, a communication device 40, and a controller 42 connected with each of the other elements. Controller 42 may show the electronic map on display 28 a and then use the electronic map to automatically cause actuators 19 and/or 20 to adjust a travel speed, a drum rotational speed, and/or a milling depth in order to avoid engagement of milling drum 12 with objects 30.
Locating device 38 may be configured to generate a signal indicative of a geographical position of the cold planer 10 relative to a local reference point, a coordinate system associated with the work area, a coordinate system associated with. Earth, or any other type of 2-D or 3-D coordinate system. For example, locating device 38 may embody an electronic receiver configured to communicate with one or more satellites, or a local radio or laser transmitting system used to determine a relative geographical location of itself. Locating device 38 may receive and. analyze high-frequency, low-power radio or laser signals from multiple locations to triangulate a relative 3-D geographical position. A signal indicative of this geographical position may then be communicated from locating device 38 to controller 42. The signal generated by location device 38 may then be correlated with the object detection signal from sensor 34 (e.g., based on a known offset distance and/or angle), such that the location of the detected objects 30 may also be determined and mapped.
Controller 42 may be configured to manage communications between cold planer 10 and an offboard entity (e.g., a central facility or another machine such as a trimming, machine—not shown). For example, controller 42 may receive signals from sensor 34 and locating device 38, and correlate the signals, filter the signals, buffer the signals, record the signals, or otherwise condition the signals before generating the electronic map and directing the map offboard via communication device 40.
Communication device 40 may include hardware and/or software that enables sending and receiving of data messages between. controller 42 and the offboard entity. The data messages may be sent and received via a direct data link and/or a wireless communication link, as desired. The direct data link may include an Ethernet connection, a connected area network (CAN), or another data link known in the art, The wireless communications may include satellite, cellular, infrared, and any other type of wireless communications that enables communication device 40 to exchange information.
Controller 42 may embody a single microprocessor or multiple microprocessors that include a means for monitoring operator and sensor input, and responsively adjusting operational characteristics of cold planer 10 based on the input. For example, controller 42 may include a memory, a secondary storage device, a clock, and a processor, such as a central processing unit or any other means for accomplishing a task consistent with the present disclosure. Numerous commercially available microprocessors can be configured to perform the functions of controller 42. It should be appreciated that controller 42 could readily embody a general machine controller capable of controlling numerous other machine functions, Various other known circuits may be associated with controller 42, including signal-conditioning circuitry, communication circuitry, and other appropriate circuitry. Controller 42 may be further communicatively coupled with an external computer system, instead of or in addition to including a computer system, as desired.

INDUSTRIAL APPLICABILITY

The disclosed control system may be used with any cold planer where object avoidance is important, The disclosed control system may provide for object avoidance by the associated cold planer through detecting and mapping out the location of the object. The disclosed control system may also provide for automated control of the cold planer based on the mapping, Operation of control system 36 will now be explained.
During operation of cold planer 10, sensors 34 may continuously monitor the work area in front of milling drum 12 to determine if any objects 30 are present. These objects 30 may be harder and/or denser than a surrounding environment and, if engaged by the tools of milling drum 12, could cause damage to milling drum 12. in one example, objects 30 include man-hole covers, pipes, sewer grates, and rocks. Sensors 34 may generate signals indicative of changes in magnetic fields and/or reflected energy waves caused by the inclusion of objects 30. These signals may be directed to controller 42 for further processing.
While sensors 34 are generating object detection signals, locating device 38 may he simultaneously generating location signals. These signals may be 2-D or 3-D signals, and provide an indication as to a location of a particular point of cold planer 10. For example, the location signals may be associated with the location of milling drum 12. Controller 42 may receive the location signals and correlate the location signals with the object detection signals. For example, when an object 30 is detected, controller 42 may determine the location of the object 30 based on the detected location of milling drum 12 and known kinematics (e.g., based on a known offset distance. and/or angle of sensors 34 from milling drum 12) of cold planer 10, Controller 42 may then generate an electronic map of the work area that shows the current location of milling drum 12 and the location of any detected objects 30. Controller 42 may continuously update the electronic map as cold planer 10 moves through the work area.
Controller 42 may then automatically adjust operation of cold planer 10 based on the electronic map. For example, controller 42 may automatically adjust a speed of cold planer 10 and/or a depth of milling drum 12, such that as milling drum 12 approaches a mapped location of object 30, milling drum 12 may be inhibited from engagement. In some instances, controller 42 may first alert the operator of cold planer 10 (e.g., via activation of warning device 28 b) before implementing automated functions. For example, controller 42 may selectively activate warning device 28 b based on a proximity of milling drum 12 to object 30. This may provide the operator with an opportunity to override the automated functions (e.g., via input device 28 c), if desired. in particular, the operator may approve of automated avoidance maneuvers or selectively instruct controller 42 to allow engagement of milling drum 12 with object 30.
In some applications, controller 42 may be configured to automatically classify a particular object 30 as a known object based on geometry (e.g., a size, shape, density, and/or magnetic property) detected by sensors 34. For example, when an object 30 is detected that has a diameter of about two feet, has a round shape, and is ferrous, controller 42 may compare these features with corresponding features of known or expected objects and determine that the detected object 30 is a manhole cover. Controller 42 may be configured to detect pipes, sewer grates, and other objects in the same way. In addition, controller 42 may be able to determine that object 30 is a rock or other type of object when the detected parameters do not match stored parameters of known objects. When the detected object 30 is recognized and/or classified as a known object, the electronic map may be updated to reflect the classification. For example, corresponding symbols may be placed on the map at the location of the detected object 30.
In some applications, controller 42 may vary the type of control implemented based on the classification of object 30. In one example, a wide clearance zone may be assigned for use in controlling milling drum 12 when object 30 is recognized as a first object type (a manhole cover), and a narrow clearance zone may be assigned when object 30 is recognized as a second object type (a sewer grate). in another example, milling drum 12 may be allowed to chew through object 30 when it is classified as a third type of object (e.g., a pvc pipe).
When controlling the movements of cold planer 10 so as to avoid contact between milling drum 12 and object 30, care should be taken to remove as much asphalt material from around object 30 as possible, without causing any damage to the work tools of milling drum 12. In some instances, this may still leave a significant amount of material around object 30 that must be removed before repaving can begin, In. these instances, controller 42 may communicate the electronic map of objects 30 offboard to another machine, such as a trimming machine (not shown). The trimming machine may be more accurately controlled and, thus, more capable of removing material that is right up against the object 30, without damaging the machine. In other instances, hand-removal of the material may be required, and the electronic map may be helpful in accomplishing this manual task.
Several advantages may be associated with the disclosed control system. For example, because sensors 34 may be integrated into cold planer 10, automated adjustment of cold planer 10 based on the signals from sensor 34 may allow high-response avoidance of detected objects 30. In addition, because controller 42 may generate an electronic map based on the signals from sensors 34, the map may be communicated offboard for manual use, for use by other automated machines, and for future reference, Further, because sensors 34 may be ground penetrating type sensors, in one embodiment, objects 30 that are not ferrous but that could still cause damage to cold planer 10 may be detected and avoided.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed control system without departing from the scope of the disclosure. Other embodiments of the control system will be apparent to those skilled in the art from consideration of the specification and practice of the conveyor 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.

Claims

What is claimed is:

1. A control system for a cold planer having a milling drum, comprising:

an obstacle detection sensor mountable to the cold planer at a location forward of the milling drum and being configured to generate a first signal indicative of an object detected within a work surface;

a locating device mountable to the cold planer and configured to generate a second signal indicative of a location of the cold planer at a time of first signal generation; and

a controller in communication with the obstacle detection sensor and the locating device, the cold planer being configured to:

generate an electronic map of a work area based on the first and second signals; and

automatically adjust operation of the cold planer based on the electronic map.

2. The control system of claim 1, wherein the obstacle detection sensor is a magnetic field detecting sensor.

3. The control system of claim 1, wherein the obstacle detection sensor is ground penetrating radar receiver.

4. The control system of claim 1, wherein:

the cold planer further includes a traction device;

the control system further includes an actuator associated with the traction device; and

the controller is configured to adjust operation of the cold planer by automatically causing the actuator to change at least one of a travel speed and a milling depth of the cold planer.

5. The control system of claim 1, wherein:

the control system further includes an actuator associated with the milling drum; and

the controller is configured to affect operation of the cold planer by automatically causing the actuator to adjust at least one of a rotational speed and a depth of the milling drum.

6. The control system of claim 1, wherein:

the control system further includes a communication device; and

the controller is further configured to communicate the electronic map offboard the cold planer.

7. The control system of claim 1, further including a warning device, wherein the controller is configured to selectively activate the warning device based on proximity of the milling drum to the object.

8. The control system of claim 1, further including a display, wherein the controller is further configured to show the electronic map on the display.

9. The control system of claim 1, further including an input device, wherein the controller is further configured to:

prompt an operator to provide input via the input device regarding the object; and

to selectively allow the milling drum to engage the object or cause the milling drum to avoid the object based on the input.

10. The control system of claim 1, wherein the controller is further configured to:

determine features of the object based on the first signal;

make a comparison of the features with features of known objects; and

selectively represent the object in the electronic map as one of the known objects based on the comparison.

11. The control system of claim 10, wherein the controller is configured to selectively allow the milling drum to engage the object or cause the milling drum to avoid the object based on the comparison.

12. The control system of claim 10, wherein the controller is configured to automatically assign a clearance zone around the object based on the comparison.

13. A method of operating a. cold planer having a milling drum, comprising:

detecting an object in a work surface being milled by the milling drum;

determining a location of the cold planer when the object is detected;

generating an electronic map of a work area based on detection of the object and the location of the cold planer; and

automatically adjusting operation of the cold planer based on the electronic map.

14. The method of claim 13, wherein detecting the object includes detecting a change in a magnetic field within the work surface.

15. The method of claim 13, wherein detecting the object includes detecting a change in energy waves reflected off the object.

16. The method of claim 13, wherein automatically adjusting operation of the cold planer includes automatically adjusting a travel speed of the cold planer.

17. The method of claim 13, wherein automatically affecting operation of the cold planer includes automatically adjusting at least one of a rotational speed and a depth of the milling drum.

18. The method of claim 13, further including:

displaying the electronic map inside an operator station of the cold planer; and

communicating the electronic map offboard the cold planer.

19. The method of claim 13, further including activating a warning device based on proximity of the milling drum to the object.

20. A cold planer, comprising:

a frame;

a traction device connected to the frame and configured to propel the cold planer;

an engine mounted to the frame and configured to drive the traction device;

a milling drum connected to the frame;

a conveyor located adjacent the milling drum;

a first actuator associated with the traction device and configured to affect at least one of a speed the traction device and a depth of the milling drum;

a second actuator associated with the milling drum and configured to affect at least one of rotational speed and the depth of the milling drum;

an operator station supported by the frame at a side opposite the milling drum;

a display disposed in the operator station;

an obstacle detection sensor mounted forward of the milling drum and being configured to generate a first signal indicative of an object detected within a work surface;

a locating device configured to generate a second signal indicative of a location of the cold planer at a time of first signal generation; and

a controller in communication with the obstacle detection sensor, the locating device, the display, and at least one of the first and second actuators, the controller being configured to:

show the electronic map on the display; and

automatically adjust operation of the at least one of the first and second actuators based on the electronic map.