SYSTEMS, METHODS, AND MACHINES FOR DETECTING AND MITIGATING DRILL STALLS WITH AN AUTOMATED FOUNDATION COMPONENT DRIVING AND ASSEMBLY MACHINE
An automated driving and assembly machine for driving foundation components, such as screw anchors, and for assembling foundations, such as truss foundations, using the driven screw anchors. The machine has a rotary driver and a hydraulic drilling tool. Sensors monitoring hydraulic pressure at the drilling tool will take incremental pressure readings during a driving operation. If the readings become clustered around a relative maximum, the controller will pause the driving operation and begin a drill stall mitigation sub-routine. This may involve retracting the drill and then hammering and releasing pressurized air to clear the stall. Clearance of the stall may also be derived by the controller from pressure readings.
This claims priority to U.S. provisional patent application 63/333,355, filed on Apr. 21, 2022, titled, “SYSTEMS, METHODS, AND MACHINES FOR DETECTING AND MITIGATING DRILL STALLS WITH AN AUTOMATED FOUNDATION COMPONENT DRIVING ASSEMBLY MACHINE”, the disclosure of which is hereby incorporated by reference in its entirety.
BACKGROUNDThe applicant of this disclosure has developed a novel foundation system for supporting single-axis solar trackers, fixed tilt solar arrays and other solar and non-solar structures. Known commercially as EARTH TRUSS, this foundation system consists of a pair of adjacent legs extending above and below ground that form a truss with the ground. In some embodiments, each leg of the EARTH TRUSS is formed from a foundation component known as a screw anchor that is driven into the ground and an upper tubular section known as an upper leg. The upper leg is attached to the top of the screw anchor and the free ends of each upper leg are then joined into a unitary truss foundation with a so-called truss cap or adapter. Different length upper legs may be used to accommodate different heights and leg angles. In the case of various single-axis trackers, the tracker bearing assembly is attached to this truss cap. In other cases, the tracker bearing may be incorporated into the truss cap in what may be called a bearing adapter.
The EARTH TRUSS foundation provides several advantages over conventional H-pile foundations for single-axis trackers, however, its multi-piece construction also creates additional complexity relative to H-piles. To construct EARTH TRUSS foundations quickly and accurately at the scale required for solar power plants, applicant also had to develop a novel machine to drive the base underground component into the ground and to facilitate accurate assembly of the truss to those driven components. This machine, known commercially as a truss driver, combines a rotary driver and a drilling tool concentrically oriented on the same mast controlled by precision automation. Automation takes operator delay and variations out of the loop to insure that a given machine will drive each screw anchor using the same program and will respond to detected conditions in real time to prevent and/or mitigate any issues as they occur. A greater discussion of automated driving operations may be found in commonly assigned patent application, Ser. No. 16/659,440, now issued U.S. Pat. No. 10,907,318, the disclosure of which is hereby incorporated by reference in its entirety.
As shown and discussed herein, the drilling tool of the truss driver extends through the rotary driver and driven foundation component to clear obstacles and drill a path for the screw anchor through hard soils and even solid rock while the rotary driver rotates the screw anchor into the ground. Drilling through the component during driving obviates the need for a separate pre-drill step and results in tighter tolerances of truss components relative to pre-drilling. Pre-drill is more expensive because it requires a separate machine, is less precise because the same bore is drilled each time, and can suffer from cave-in necessitating other remediation. Also, because the truss is assembled while the machine remains oriented above the foundation location, the resulting foundation is normally ready for tracker installation without a subsequent alignment correction step normally required for H-piles.
By using an expanding drill bit passed through the screw anchor, the borehole diameter can be controlled by the distance the bit is extended out of or ahead of the screw anchor. In fact, the expanding bit enables the borehole to have a wider diameter than the inside diameter of the foundation component which, in turn, enables the external thread form at the lower end of each anchor to engage with the surrounding media, even if it is solid rock. However, like the truss itself, these additional controllable features require additional control over the drilling process to prevent damaging the bore hole (over excavating), damaging the screw anchor by forcing into a hole that it will not screw into, and even damaging the drill bit or drilling tool itself. In particular, with automated driving, it is possible for the drilling operation to stall, that is, further torque and downforce fail to result in further penetration of the bit. When this happens, it can damage the bit, the drill rod, the hydraulic system, and even the foundation component being driven before a human operator is aware or has the opportunity to stop the automated drilling operation to attempt to mitigate the stall. In recognition of this problem, various embodiments of this disclosure provide systems, methods, and machines that leverage the automation of the truss driver machine to identify situations requiring mitigation quickly and autonomously and to perform mitigations strategies before any damage to any tools or components occurs.
The following description is intended to convey a thorough understanding of the embodiments described by providing a number of specific embodiments and details involving control systems for foundation component driving machines. It should be appreciated, however, that the present invention is not limited to these specific embodiments and details, which are exemplary only. It is further understood that one possessing ordinary skill in the art in light of known systems and methods, would appreciate the use of the invention for its intended purposes and benefits in any number of alternative embodiments, depending upon specific design and other needs, including pile driving and drilling machines generally.
Turning now to the drawing figures,
Assembly of the truss foundation shown in
Mast 110, as shown, extends in a straight-line 20+feet and has a pair of parallel rails 115 extending its length. A drive chain 125 runs between rails 115 between chain tensioners 120 at either end of the mast. A lower hydraulic crowd motor 170 powers drive chain 125 moving the lower and upper crowd sleds (130, 150 respectively) up and down mast 110 along parallel rails 115. Lower crowd 150 holds the rotary driver 155 and target plate 160. Rotary driver 155 at its bottom end accepts the head of a screw anchor or other foundation component and applies torque to drive it into the ground once the mast is oriented to the correct driving location and orientation. Simultaneous downforce comes from lower crowd motor 170. An automated controller, not shown in
The heart of the automated control system shown in
As shown in
Once an operator initiates an automated screw anchor driving operation, controller 305, while receiving feedback from one or more of the sensor nodes 320A, through 320N, controls various one of the control nodes 315A, through 315N in accordance with stored program data to orient the mast to the correct driving vector and to initiate the embedment operation to embed a screw anchor or other foundation component to the desired embedment depth. Information from one or more of the sensor nodes 320A, through 320N will enable the controller to determine that the component has reached the target embedment depth so that the drive operation may be appropriately terminated upon completion.
In various embodiments, although the driving operations are performed on an automated basis, a handheld or neck-worn remote control may be used to control the machine, that is, to initiate and terminate the automated process. Once the operation is initiated, in various embodiments, controller 305 autonomously monitors various performance metrics of the mast components to optimize each operation. However, situations may occur that require manual intervention. For example, while driving, it is possible that spoils may become impacted in the bore hole, or the bit may become stuck in a rock or other obstruction. A skilled operator who is paying close attention may be able to detect this stalled situation simply by listening and watching the machine, however, this requires the operator to be constantly paying attention. If missed, this condition could continue to persist until unnecessary wear and tear or immediate damage to one or more of the mast component or foundation component occurs. Ideally, controller 305 will detect one or more variables from the array of sensor nodes to enable stall conditions to be quickly detected so that they may be mitigated before damage to the drill bit, foundation component, or machine occurs.
To that end, various embodiments of the invention provide systems and methods for using the automated control system used to drive foundation components into the ground with drill assist to quickly detect the occurrence of a situation requiring intervention, to intervene, and to mitigate the situation without any input from the machine operator, or without the machine operator even being aware that it happened.
With continued reference to
Turning now to
If, in step 415, the controller determines that a stall is occurring, operation of the program advances to step 425 where stall mitigation is initiated. Stored program code causes the controller to begin executing the process shown in
Next, in step 445, the stored program code causes the controller to activate the drilling tool and upper crowd motor to advance the drill rod and bit back down into the bore hole while the drill rotates. As mentioned herein, if a button bit is being used, this will involve hammering the drill bit as well as rotating it. In step 450, hydraulic pressure at the drilling tool is continuously monitored by the controller so that it can determine whether the stall has been successfully mitigated or “cleared” as indicated in
If, at step 450 the controller determines that the stall has been cleared, as indicated, for example, by pressure readings at the drilling tool returning to normal, stored program code, in the exemplary method shown, this causes the processor to return back to step 410 of flow chart 400 of
Referring again to
It should be appreciated that the embodiments described and claimed herein are exemplary only. Those of ordinary skill in the art will appreciate modifications and substitutions that retain the spirit and scope of the invention. Thus, such modifications are intended to fall within the scope of the following appended claims. For example, although the various embodiments have been described in the context of a truss driver machine, it should be appreciated that various embodiments of the invention may be equally applicable to machines that drive conventional H-piles such as vibratory and percussive hammering machines and solar pile driving machines that combine a small drilling rig with a pile driver Therefore, although some of the embodiments of the present invention have been described herein in the context of a particular implementation in a particular environment for a particular purpose, those of ordinary skill in the art will recognize that this disclosure's usefulness is not limited thereto and that the embodiments of the present inventions can be beneficially implemented in any number of environments for any number of purposes. Accordingly, the claims set forth below should be construed in view of the full breath and spirit of the embodiments of the present invention as disclosed herein. Thus, such modifications are intended to fall within the scope of the following appended claims. Further, although some of the embodiments of the present invention have been described herein in the context of a particular implementation in a particular environment for a particular purpose, those of ordinary skill in the art will recognize that its usefulness is not limited thereto and that the embodiments of the present inventions can be beneficially implemented in any number of environments for any number of purposes.
Claims
1. A machine for driving foundation components comprising:
- a base machine;
- an adjustable mast attached to the base machine;
- a rotary driver, movably attached to the mast and controllable to drive a foundation component into underlying ground to a target embedment depth;
- a drilling tool movably attached to the mast and controllable to operate a drill rod through the rotary driver; and
- a control system including a controller executing a control program for automatically controlling the rotary driver and the drilling tool to drive a foundation component to a desired embedment depth, wherein the control program contains program code causing the controller to detect and mitigate a stall of the drilling tool while driving a foundation component to the target embedment depth.
2. The machine according to claim 1, wherein the program code causing the controller to detect and mitigate a stall of the drilling tool comprises program code that instructs the controller to monitor hydraulic pressure sensor data comprising a series of sequential pressure readings from within the drilling tool to detect a stall of the drilling tool.
3. The machine according to claim 2, wherein the program code that instructs the controller to monitor hydraulic pressure sensor data from within the drilling tool causes the controller to determine if the hydraulic pressure sensor data indicates a distribution of values over a pre-determined time period that are clustered around a relative maximum pressure reading.
4. The machine according to claim 3, wherein clustered around a relative maximum pressure reading comprises determining a relative maximum and from the hydraulic pressure sensor data and determining if during the predetermined time period most pressure readings are within 10 PSI of the relative maximum value.
5. The machine according to claim 4, wherein most comprises at least 90% of the pressure readings.
6. The machine according to claim 1, wherein the program code causing the controller to detect and mitigate a stall of the drilling tool comprises program code that causes the controller to pause driving the foundation component to clear the stall prior to resuming driving the foundation component to the target embedment depth.
7. The machine according to claim 6, wherein clearing the stall comprises controlling the drilling tool to temporarily withdrawal the drill bit and then to control the drilling tool to advance the drill bit ahead of the foundation component and ejecting pressurized air from the drill bit to clear the stall.
8. The machine according to claim 6, wherein the program code further causes the controller to control the rotary driver to resume driving the foundation component once the stall is cleared until the foundation component reaches the target embedment depth.
9. The machine according to claim 8, where the program code causes the controller to determine that a stall has been cleared by monitoring hydraulic pressure sensor data while clearing the stall and determining that the stall has cleared when the hydraulic pressure sensor data is no longer clustered around a relative maximum reading.
10. A stall mitigation system for an automated foundation component embedment machine comprising:
- a controller executing stored program code for controlling the rotary driver and drilling tool to embed a foundation component into underlying ground;
- a plurality of control nodes; and
- a plurality of sensor nodes, wherein the program code causes the controller to control the control nodes to begin an automated operation to embed a foundation component into the underlying ground, and, based on an output of at least one of the sensor nodes, to determined that a stall of at least one of the control nodes has occurred while performing the automated operation to embed the foundation component.
11. The system according to claim 10, wherein the stored program code causes the controller to determine that a stall of at least one of the control nodes has occurred when the output of the at least one sensor node indicates a distribution of sequential pressure readings taken by the at least one sensor node over a pre-determined time period are clustered around a relative maximum value.
12. The system according to claim 11, wherein the output of the at least one sensor nodes indicates a distribution of pressure readings over a pre-determined time period that are clustered around a relative maximum value when at least 90-percent of the readings are within 10 PSI of that relative maximum value during the pre-determined time period.
13. The system according to claim 10, wherein in response to determining that a stall of at least one of the control nodes has occurred, the stored program code causes the controller to pause embedment of the foundation component and to control at least one of the control nodes to clear the stall.
14. The system according to claim 10, wherein the at least one control nodes is a hydraulic drilling tool.
15. The system according to claim 14, where the stored program code causes the controller to control the hydraulic drilling tool to perform an automated mitigation process to clear the stall.
16. The system according to claim 15, wherein the automated mitigation process to clear the stall comprises controlling the drilling tool to partially withdrawal the drill bit and to advance the drill ahead of the foundation component while ejecting pressurized air from the drill bit until the stall is cleared, such condition being determined by the controller when the sequential pressure readings taken by the at least one sensor node are no longer clustered around a relative maximum.
17. A method of controlling an automated machine for driving foundation components comprising:
- with a digital controller communicatively coupled to the automated machine, executing stored program code causing the controller to control the automated machine to attempt to embed a foundation component into underlying ground to a target embedment depth; and
- with the digital controller, executing stored program code causing the controller to monitor an output of at least one pressure sensor connected to a component of the automated machine to determine if a stall of the component has occurred and to mitigate the stall before continuing to attempt to embed the foundation component.
18. The method according to claim 17, wherein executing stored program code causing the controller to control the automated machine to attempt to embed a foundation component into underlying ground to a target embedment depth comprises controlling with the digital controller at least a rotary driver, a drive train, and a drilling tool to attempt to embed the foundation component.
19. The method according to claim 17, wherein the stored program code causes the controller to detect the occurrence of a stall by monitoring an output of at least one pressure sensor sensing hydraulic pressure at the drilling tool and determining that a stall has occurred if the output indicates a distribution of sequential pressure readings over a pre-determined time period that are clustered around a relative maximum pressure reading.
20. The method according to claim 19, wherein clustered around comprises determining a relative maximum pressure reading from the sensor data during the predetermined time period and determining if at least a 90 percent of the values are within 10 PSI of that maximum pressure reading.
Type: Application
Filed: Apr 21, 2023
Publication Date: Oct 26, 2023
Inventors: Steve Kraft (Albany, CA), Tom Anderson (Oakland, CA), Sam Whittemore (Readfield, ME), Hector Arvizu (Yuma, AZ), Sergio Araujo (Yuma, AZ)
Application Number: 18/137,694