U.S. patent application number 13/182297 was filed with the patent office on 2012-01-19 for robotic heliostat system and method of operation.
Invention is credited to Wasiq Bokhari, Thomas Currier, Daniel Fukuba, Salomon Trujillo.
Application Number | 20120012101 13/182297 |
Document ID | / |
Family ID | 45465923 |
Filed Date | 2012-01-19 |
United States Patent
Application |
20120012101 |
Kind Code |
A1 |
Trujillo; Salomon ; et
al. |
January 19, 2012 |
ROBOTIC HELIOSTAT SYSTEM AND METHOD OF OPERATION
Abstract
A system and method for operating a robotic controller to
automatically position multiple solar surfaces in order to increase
solar energy generation from the solar surfaces. In an embodiment
the robotic controller travels in a sealed track and adjusts the
solar surfaces using magnetic communication.
Inventors: |
Trujillo; Salomon; (Redwood
City, CA) ; Fukuba; Daniel; (Palo Alto, CA) ;
Currier; Thomas; (Rochester, MN) ; Bokhari;
Wasiq; (Half Moon Bay, CA) |
Family ID: |
45465923 |
Appl. No.: |
13/182297 |
Filed: |
July 13, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61364729 |
Jul 15, 2010 |
|
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61419685 |
Dec 3, 2010 |
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Current U.S.
Class: |
126/601 ;
126/607 |
Current CPC
Class: |
F24S 30/452 20180501;
F24S 2030/115 20180501; Y02E 10/47 20130101; F24S 2030/134
20180501; F24S 50/20 20180501 |
Class at
Publication: |
126/601 ;
126/607 |
International
Class: |
F24J 2/40 20060101
F24J002/40; F24J 2/52 20060101 F24J002/52 |
Claims
1. A robotic controller for controlling a position of multiple
solar surfaces in response to movement of multiple solar surface
adjustment wheels, each solar surface having a corresponding solar
surface adjustment wheel, the robotic controller positioned on a
track, the robotic controller including: a processing unit, a
location determining unit, communicatively coupled to said
processing unit, for determining a position of the robotic
controller; a drive system, for moving said robotic controller
along the track in response to instructions from the processing
unit; an adjustment determining system for determining first
adjustment parameters for a first solar surface adjustment wheel of
said multiple solar surface adjustment wheels; and an engagement
system for adjusting the first solar surface adjustment wheel based
upon said first adjustment parameters.
2. The robotic controller of claim 1, wherein said location
determining unit identifies a first location of the robotic
controller on the track that is adjacent to the solar surface
adjustment wheel; and wherein said drive system positions said
robotic controller at said first location.
3. The robotic controller of claim 2, wherein said robotic
controller includes: a Hall effect sensors; and said location
determining unit utilizes magnetic communication between said Hall
effect sensor and one of the solar surface adjustment wheels to
identify said robotic controller location as being adjacent to said
one of the solar surface adjustment wheels.
4. The robotic controller of claim 3, wherein said communication
between said Hall effect sensors and one of said solar surface
adjustment wheels identifies said one of the solar surface
adjustment wheel as said first solar surface adjustment wheel and
said location as said first location.
5. The robotic controller of claim 2, wherein robotic controller
includes: a Hall effect sensor; and said engagement system utilizes
magnetic coupling between said Hall effect sensor and said first
solar surface adjustment wheel to rotate said first solar surface
adjustment wheel based upon said first adjustment parameters.
6. The robotic controller of claim 1, wherein said engagement
system includes a rack and pinion mechanism, said rack and pinion
mechanism automatically adjustable based upon said first adjustment
parameters, said engagement system adjusts the first solar
adjustment wheel while the robotic controller is moving.
7. The robotic controller of claim 1, wherein the track in which
the robotic controller traverses is sealed to prevent any
significant ingress of dust or water.
8. The robotic controller of claim 1, further comprising drive
wheels to propel the robotic controller along the track.
9. The robotic controller of claim 1, further comprising: a power
storage system for storing power to said robotic controller.
10. The robotic controller of claim 9, wherein said power storage
system is an electric energy storage device.
11. The robotic controller of claim 9, wherein said power storage
system recharges wirelessly.
12. The robotic controller of claim 1, further comprising an energy
receiving device for receiving power from the track
13. The robotic controller of claim 12, wherein said energy
receiving device receives power either inductively from the track
or using a direct connection to the track.
14. The robotic controller of claim 1, wherein said location
determining unit utilizes a triangulation methodology to identify
the location of the robotic controller, the triangulation
methodology receives signals from at least three devices external
to the robotic controller positioned in the local vicinity.
15. The robotic controller of claim 1, wherein said location
determining unit includes a global positioning satellite receiver
to identify the location of the robotic controller.
16. The robotic controller of claim 1, further comprising: a
climate control system disposed to receive signals from said
processor for moderating the environmental conditions in which the
robotic controller operates.
17. The robotic controller of claim 1, further comprising: a
communication system, to communicate wirelessly with at least one
of a central server, a second robotic controller, and/or a central
controller.
18. The robotic controller of claim 1, further comprising: a
camera, for detecting at least one of the orientation of one or
more of the solar surfaces and/or abnormalities in the track.
19. A method for a robotic controller to control a position of
multiple solar surfaces in response to movement of multiple solar
surface adjustment wheels, each solar surface having a
corresponding solar surface adjustment wheel, the robotic
controller positioned on a track, the method comprising the steps
of: determining a position of the robotic controller; moving said
robotic controller along the track to a position adjacent to a
first of said multiple solar surface adjustment wheels; determining
first adjustment parameters for said first solar surface adjustment
wheel; and adjusting the first solar surface adjustment wheel based
upon said first adjustment parameters.
20. The method of claim 19, further comprising the steps of:
wirelessly communicating with at least one of a central server, a
second robotic controller, and/or a central controller.
Description
RELATED APPLICATIONS
[0001] This application claims priority from U.S. provisional
application No. 61/364,729 filed on Jul. 15, 2010, and U.S.
provisional application No. 61/419,685 filed on Dec. 3, 2010 which
are all incorporated by reference herein in their entirety. This
application is related to U.S. application Ser. No. 13/118,274
which is incorporated by reference herein in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to solar tracking and
calibration devices, and in particular tracking systems for
photovoltaic, concentrated photovoltaic, and concentrated solar
thermal systems that require constant repositioning to maintain
alignment with the sun.
BACKGROUND OF THE INVENTION
[0003] In an attempt to reduce the price of solar energy, many
developments have been made with respect to lowering the cost of
precisely repositioning and calibrating a surface with two degrees
of freedom. In concentrated solar thermal systems, heliostat arrays
utilize dual axis repositioning mechanisms to redirect sunlight to
a central tower by making the normal vector of the heliostat mirror
bisect the angle between the current sun position and the target.
Heat generated from the central tower can then be used to create
steam for industrial applications or electricity for the utility
grid.
[0004] Concentrated photovoltaic (CPV) systems take advantage of
dual axis mechanisms in order to achieve a position where the
vector normal to the CPV surface is coincident with the solar
position vector. When the CPV surface is aligned to the sun,
internal optics are able to concentrate sunlight to a small, high
efficiency photovoltaic cell.
[0005] Dual axis positioning systems also enable flat plate
photovoltaic (PV) systems to produce more power through solar
tracking Compared to fixed tilt systems, dual axis PV systems
produce 35-40% more energy on an annualized basis. While this
increase in energy production may seem attractive, current
technology marginalizes the value of biaxial solar tracking by
increasing total system capital and maintenance costs by
40-50%.
[0006] Traditional solutions to the problem of controlling and
calibrating an individual surface fall into one of three main
categories: active individual actuation, module or mirror ganging,
and passive control. In the active individual actuation model, each
dual axis system requires two motors, a microprocessor, a backup
power supply, field wiring, and an electronic system to control and
calibrate each surface. Moreover, all components must carry a 20+
year lifetime and the system needs to be sealed from the harsh
installation environment. In an attempt to spread out the fixed
cost of controlling an individual surface, conventional engineers'
thinking within the individual actuation paradigm are building 150
square meter (m 2) heliostats and 225 square meter PV/CPV trackers.
While control costs are reduced at this size, large trackers suffer
from increased steel, foundational, and installation
requirements.
[0007] Another approach attempts to solve the fixed controls cost
problem by ganging together multiple surfaces with a cable or
mechanical linkage. While this effectively spreads out motor
actuation costs, it places strict requirements on land grading,
greatly complicates the installation process, and incurs a larger
steel cost due to the necessary stiffness of the mechanical
linkages. Due to constant ground settling and imperfections in
manufacturing and installation, heliostat and CPV systems require
individual adjustments that increase system complexity and
maintenance cost.
[0008] Passive systems utilizing hydraulic fluids, bimetallic
strips, or bio-inspired materials to track the sun are limited to
flat plate photovoltaic applications and underperform when compared
to individually actuated or ganged systems. Moreover, these systems
are unable to execute backtracking algorithms that optimize solar
fields for energy yield and ground coverage ratio.
SUMMARY
[0009] A robotic controller for controlling a position of multiple
solar surfaces in response to movement of multiple solar surface
adjustment wheels, each solar surface having a corresponding solar
surface adjustment wheel, the robotic controller positioned on a
track, the robotic controller including a processing unit, a
location determining unit, communicatively coupled to the
processing unit, for determining a position of the robotic
controller, a drive system, for moving the robotic controller along
the track in response to instructions from the processing unit, an
adjustment determining system for determining first adjustment
parameters for a first solar surface adjustment wheel of the
multiple solar surface adjustment wheels; and an engagement system
for adjusting the first solar surface adjustment wheel based upon
the first adjustment parameters.
[0010] Particular embodiments and applications of the present
invention are illustrated and described herein, it is to be
understood that the invention is not limited to the precise
construction and components disclosed herein and that various
modifications, changes, and variations may be made in the
arrangement, operation, and details of the methods and apparatuses
of the present invention without departing from the spirit and
scope of the invention which is set forth in the claims.
[0011] In an embodiment the invention can be used in conjunction
with a heliostat or solar tracker that has its microprocessor,
azimuth drive, elevation drive, central control system, and wiring
removed. The elimination of these components allows for extreme
cost reduction over conventional systems, and creates a fourth
actuation paradigm: passive with active robotic control. In this
model, a single robotic controller assumes the functional duties of
calibrating and adjusting two or more solar surfaces in 3D
space.
[0012] In a second embodiment of the present invention a robotic
controller can move between passive solar surfaces and accurately
control the rotation of one or more adjustment wheels near
aforementioned surface. These adjustment wheels may be connected to
a rigid or flexible shaft that could be routed to a gear train,
lead screw assembly, or directly to the solar surface. The gear
train, lead screw assembly, or direct drive system transforms
rotational input motion into movement of the solar surface. If the
gear train, lead screw assembly, or direct drive system is back
drivable, additional adjustment wheels may be used to actuate
braking mechanisms. The robotic controller is able to reposition a
solar surface in one or two axes through control of one or more
adjustment wheels and therefore replaces 100+ sets of wiring,
motors, central controllers, and calibration sensors. It also
eliminates the core engineering assumption--a high, relatively
fixed control cost per surface--that drives the development of
large heliostats and solar trackers.
[0013] As an individual robot must endure 5 to 8 million adjustment
cycles per year, the ideal adjustment interface will not use
contact to control the position of the adjustment wheel. In a third
embodiment, the invention can utilize a magnetic or electromagnetic
interface to control the rotation of the adjustment wheels. If an
axial flux motor mechanism is utilized, the robotic controller's
adjustment wheel interface may contain no moving parts.
[0014] In a fourth embodiment the robotic controller can sense the
position of an adjustment wheel before, during, and after
adjustment. This may be achieved through the use of Hall effect
sensors on the robotic controller and a distinct magnet or piece of
metal on the adjustment wheel. Methods of metal detection include,
but are not limited to: Very Low Frequency (VLF), Pulse Induction
(PI), and Beat-Frequency Oscillation (BFO). The robot may also use
optical, electromagnetic, or physical marking systems and sensing
methods to determine the instantaneous position of an adjustment
wheel. This interface may also be used to detect an individual
solar surface station in order to reduce the complexity of an
individual robot's station sensing mechanism.
[0015] In a fifth embodiment, the robotic controller is optimized
for rapid adjustment of solar surfaces. The robotic adjustor can
quickly analyze: 1) the robotic controller's location in 3D space,
2) Its relation to a solar surface in 3D space, 3) The current sun
position based on time of day and location, and 4) the desired
pointing position. Once these four variables are known, the robotic
controller may calculate the necessary amount of adjustment for an
individual solar surface. For PV and CPV applications, the solar
surface may be pointed directly toward the sun or at an optimal
angle as defined by backtracking control algorithms. In addition,
for PV applications, the robot may utilize existing methods that
rely on the location, date and time information to determine the
position of the sun and point the PV panel in an open loop fashion.
Heliostat power tower systems will require the solar surface to
bisect an angle between the sun and a central target. As the solar
surfaces will not be constantly updated, the optimal position in
some applications will place the surface such that it will be in
its best orientation midway between adjustments. For example, if 26
degrees is the optimal elevation angle at the time of the
adjustment, and 27 degrees will be the new maximum at the time of
the subsequent adjustment, a robotic controller may place the
surface at 26.5 degrees tilt.
[0016] Once calculated, the robotic controller may use an onboard
adjustment interface to control the position of a solar surface.
The final step in the robotic controller's process is to analyze
the distance to an adjacent adjustment station, and utilize an
onboard or external drive mechanism to reposition itself for a
subsequent adjustment.
[0017] In a sixth embodiment two, three, or more grades of robotic
controllers can be used to cost effectively reposition a field of
solar surfaces. The top and most expensive grade robotic controller
may include all mechanisms necessary to precisely calibrate and
adjust a field of solar surfaces. The mid grade robotic controller
may contain all mechanisms needed to reposition a solar surface and
would be built to withstand ten or more years of field operation.
The low-grade robotic controller may have the minimum number of
functional components to adjust a solar surface quickly, and may be
engineered for low cost over longevity.
[0018] The ideal passively actuated field may utilize one top grade
robotic controller for initial calibration and re-calibration
purposes. Mid grade robotic controllers may be used for normal
operation and would adjust the solar surfaces based on inputs from
the top grade robotic controller. Low-grade robotic controllers may
be used in emergency situations and would enable rapid and low cost
emergency defocus and/or wind stow.
[0019] In a seventh embodiment a field of robotic controllers to
communicate with each other and/or a central controller system via
a wireless network, direct link system, external switch, or by
storing data near individual solar surfaces or groups of solar
surfaces.
[0020] In an eighth embodiment, the robotic controller includes
multiple adjustment wheel interfaces so that a multiplicity of
solar surfaces can be adjusted simultaneously.
[0021] In a ninth embodiment the robotic controller can control the
position of an individual adjustment wheel or wheels without
stopping. This may be achieved using a gear rack and pinion system
that uses contact, magnetism, and/or electromagnetism to rotate an
adjustment wheel.
[0022] In a tenth embodiment the robotic controller can move
between stations through a hermetically sealed tube to prevent
large object, water, and dust ingress. It also may be desirable for
the robotic controller to be hermetically sealed in order to add
another layer of ingress redundancy.
[0023] In an eleventh embodiment the robot transport tube can be
routed such that the robotic controllers can be easily returned to
a central location.
[0024] In a twelfth embodiment two or more robotic controllers can
adjust one group of solar surfaces. This enables the solar surface
repositioning system to be redundant in the case of a single
robotic failure.
[0025] In a thirteenth embodiment the robotic controller can
include an onboard climate control system that utilizes heat sinks,
active cooling/heating systems, and moisture control mechanisms to
maintain a constant temperature and environment for internal
components. This system is particularly useful in extending the
effective life of various onboard energy storage mechanisms.
[0026] In a fourteenth embodiment the robotic controller can be
charged wirelessly. If electromagnetic coils are used to control
the rotation of the adjustment wheels, this interface could be
reused to charge an onboard energy storage system inductively.
[0027] In a fifteenth embodiment a robotic controller can include a
diagnostic system that is able to relay the health of onboard
components to other robotic controllers and/or a central control
system. This diagnostic system may communicate a regular and
periodic message back to the remote operator or be accessed as
needed. This system may also be used for in-field quality assurance
of passive trackers or heliostats as the robot may actively measure
the amount of torque or energy needed to control the position of a
solar surface's adjustment wheel. This system may also be used for
defect detection in the case that a solar surface's adjustment
wheel cannot be rotated. The robotic controller may also utilize
onboard sensors to determine if the robot transport tube has any
faults.
[0028] In a sixteenth embodiment faulty solar surfaces for PV and
CPV applications can be detected. In this model, the robotic
controller may communicate with a central power collection system
to determine the immediate output from a field of solar surfaces.
If a single solar surface is rotated away from the sun, and the
central power collection system detects no change in power output,
the robotic controller may deem the solar surface to be defective.
It may also place the solar surface in a special orientation to
alert field maintenance workers that a piece of a PV or CPV system
is malfunctioning.
[0029] In a seventeenth embodiment various pre-programmed control
protocols and algorithms can be incorporated into the robotic
controller for dealing with various field level scenarios. These
robotic control algorithms may also be updated by a field or remote
operator.
[0030] In an eighteenth embodiment various security features in the
robot can be incorporated to deter from reverse engineering and
theft. The robot may also include a tracking feature to enable
recovery of lost or stolen robots.
[0031] The features and advantages described in the specification
are not all inclusive and, in particular, many additional features
and advantages will be apparent to one of ordinary skill in the art
in view of the drawings and specification. Moreover, it should be
noted that the language used in the specification has been
principally selected for readability and instructional purposes,
and may not have been selected to delineate or circumscribe the
inventive subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 is an illustration a passive solar surface that can
be precisely repositioned without an individual microprocessor,
azimuth drive motor, elevation drive motor, central control system,
backup power supply, or calibration sensor in accordance with an
embodiment of the present invention.
[0033] FIG. 2 is an illustration of a passive solar tracker or
heliostat that does not require a gear reduction to transform
rotational input motion from an adjustment wheel or wheels into
single or dual axis control of a solar surface in accordance with
an embodiment of the present invention.
[0034] FIG. 3 is an illustration of a robotic controller in
accordance with an embodiment of the present invention.
[0035] FIG. 4 is an illustration of an embodiment of a non-contact
interface between a robotic controller and an adjustment wheel.
[0036] FIG. 5 is an illustration of various components of the
robotic controller in accordance with an embodiment of the present
invention.
[0037] FIG. 6 is a flowchart of the operation of the robotic
controller in accordance with an embodiment of the present
invention.
[0038] FIG. 7 is a flowchart of the operation of a mid-grade
robotic controller in accordance with an embodiment of the present
invention.
[0039] FIG. 8 is a flowchart of the operation of a lower-grade
robotic controller in accordance with an embodiment of the present
invention.
[0040] FIG. 9 is an illustration of some communication techniques
that may be used by the robotic controllers in accordance with an
embodiment of the present invention.
[0041] FIG. 10 is an illustration of a robotic controller with
multiple adjustment wheel interfaces in accordance with an
embodiment of the present invention.
[0042] FIG. 11 is an illustration of a robotic controller that is
able to control adjustment wheels without stopping at an adjustment
station in accordance with an embodiment of the present
invention.
[0043] FIG. 12 is an illustration showing the manner in which a
robot transport tube may be routed in a system with many solar
surfaces in accordance with an embodiment of the present
invention.
[0044] FIG. 13 is an illustration of a climate control system for
the robotic controller in accordance with an embodiment of the
present invention.
[0045] FIG. 14 is an illustration of a robotic controller that
utilizes a wireless power transfer interface to charge an energy
storage mechanism in accordance with an embodiment of the present
invention.
[0046] FIG. 15 is a flowchart of an operational process of a
robotic controller's onboard diagnostic and quality assurance
system in accordance with an embodiment of the present
invention.
[0047] The figures depict various embodiments of the present
invention for purposes of illustration only. One skilled in the art
will readily recognize from the following discussion that
alternative embodiments of the structures and methods illustrated
herein may be employed without departing from the principles of the
invention described herein.
DETAILED DESCRIPTION OF THE INVENTION
[0048] A preferred embodiment of the present invention is now
described with reference to the figures where like reference
numbers indicate identical or functionally similar elements. Also
in the figures, the left most digits of each reference number
corresponds to the figure in which the reference number is first
used.
[0049] Reference in the specification to "one embodiment," "a first
embodiment," "a second embodiment or to "an embodiment" (for
example) means that a particular feature, structure, or
characteristic described in connection with the embodiments is
included in at least one embodiment of the invention. The
appearances of the phrase "in one embodiment," "a first
embodiment," "a second embodiment" or "an embodiment" (for example)
in various places in the specification are not necessarily all
referring to the same embodiment.
[0050] Some portions of the detailed description that follows are
presented in terms of algorithms and symbolic representations of
operations on data bits within a computer memory. These algorithmic
descriptions and representations are the means used by those
skilled in the data processing arts to most effectively convey the
substance of their work to others skilled in the art. An algorithm
is here, and generally, conceived to be a self-consistent sequence
of steps (instructions) leading to a desired result. The steps are
those requiring physical manipulations of physical quantities.
Usually, though not necessarily, these quantities take the form of
electrical, magnetic or optical signals capable of being stored,
transferred, combined, compared and otherwise manipulated. It is
convenient at times, principally for reasons of common usage, to
refer to these signals as bits, values, elements, symbols,
characters, terms, numbers, or the like. Furthermore, it is also
convenient at times, to refer to certain arrangements of steps
requiring physical manipulations or transformation of physical
quantities or representations of physical quantities as modules or
code devices, without loss of generality.
[0051] However, all of these and similar terms are to be associated
with the appropriate physical quantities and are merely convenient
labels applied to these quantities. Unless specifically stated
otherwise as apparent from the following discussion, it is
appreciated that throughout the description, discussions utilizing
terms such as "processing" or "computing" or "calculating" or
"determining" or "displaying" or "determining" or the like, refer
to the action and processes of a computer system, or similar
electronic computing device (such as a specific computing machine),
that manipulates and transforms data represented as physical
(electronic) quantities within the computer system memories or
registers or other such information storage, transmission or
display devices.
[0052] Certain aspects of the present invention include process
steps and instructions described herein in the form of an
algorithm. It should be noted that the process steps and
instructions of the present invention could be embodied in
software, firmware or hardware, and when embodied in software,
could be downloaded to reside on and be operated from different
platforms used by a variety of operating systems. The invention can
also be in a computer program product which can be executed on a
computing system.
[0053] The present invention also relates to an apparatus for
performing the operations herein. This apparatus may be specially
constructed for the purposes, e.g., a specific computer, or it may
comprise a general-purpose computer selectively activated or
reconfigured by a computer program stored in the computer. Such a
computer program may be stored in a computer readable storage
medium, such as, but is not limited to, any type of disk including
floppy disks, optical disks, CD-ROMs, magnetic-optical disks,
read-only memories (ROMs), random access memories (RAMs), EPROMs,
EEPROMs, magnetic or optical cards, application specific integrated
circuits (ASICs), or any type of media suitable for storing
electronic instructions, and each coupled to a computer system bus.
Memory can include any of the above and/or other devices that can
store information/data/programs. Furthermore, the computers
referred to in the specification may include a single processor or
may be architectures employing multiple processor designs for
increased computing capability.
[0054] The algorithms and displays presented herein are not
inherently related to any particular computer or other apparatus.
Various general-purpose systems may also be used with programs in
accordance with the teachings herein, or it may prove convenient to
construct more specialized apparatus to perform the method steps.
The structure for a variety of these systems will appear from the
description below. In addition, the present invention is not
described with reference to any particular programming language. It
will be appreciated that a variety of programming languages may be
used to implement the teachings of the present invention as
described herein, and any references below to specific languages
are provided for disclosure of enablement and best mode of the
present invention.
[0055] In addition, the language used in the specification has been
principally selected for readability and instructional purposes,
and may not have been selected to delineate or circumscribe the
inventive subject matter. Accordingly, the disclosure of the
present invention is intended to be illustrative, but not limiting,
of the scope of the invention.
[0056] Referring now to the drawings, FIG. 1 depicts a passive
surface (101) that can be precisely repositioned without an
individual microprocessor, azimuth drive motor, elevation drive
motor, central control system, backup power supply, or calibration
sensor. Two adjustment wheels (102) controlled by a single robotic
controller may actuate this system through a flexible or rigid
drive shaft (103). The depicted system uses a flexible cable to
transmit rotational motion from a fixed adjustment wheel to the
azimuth gear train (104) and the elevation lead screw assembly
(105). Fixed adjustment wheels are desirable as they enable a
relatively simple robotic controller that can move along a track or
tube (106). However, this design constraint is not necessary as the
robotic controller does not need to be confined to a set path, and
can move freely throughout a field of solar surfaces.
[0057] The robot transport track may include a hollow square or
circular tube made out of aluminum, steel, non-ferrous metals,
ferrous metals, plastic, or composite materials. The passive solar
surface may be supported by a number of foundation types including
but not limited to: driven pier (107), ground screw, ballasted, or
simply bolted to a rigid surface. The robot transport tube may also
be used as a foundational support for individual passive solar
surfaces.
[0058] FIG. 2 demonstrates an embodiment of a passive solar tracker
or heliostat that does not require a gear reduction to transform
rotational input motion from an adjustment wheel (102) or wheels
into single or dual axis control of a solar surface. The system may
be actuated in a tip-tilt fashion directly by a flexible drive
shaft (103). In one embodiment, the flexible drive shaft connects
directly to a pin joint (201) that is rigidly fixed to one
rotational axis. Rotation of the adjustment wheel therefore alters
the rotation of the solar surface in a 1:1 manner on one axis. This
system may utilize friction to lock the position of a solar surface
or other active braking mechanisms described in patent application
Ser. No. 13/118,274, referenced above.
[0059] FIG. 3 demonstrates the present invention's core actuation
paradigm of passive systems with active robotic control. A robotic
controller (301) is able to propel itself along a track (106), stop
near a solar surface (101), and precisely control the rotation of
one or more adjustment wheels (102) linked to aforementioned solar
surface using an onboard adjustment wheel interface (302). Each
adjustment wheel is connected to a rigid or flexible shaft that can
be routed to accommodate many passive tracker designs. The present
invention focuses on features of the robotic controller to ensure
that the adjustment wheels are reliably and precisely
repositioned.
[0060] It is desirable to provide a large amount of input torque to
the adjustment wheels as to decrease the gear reduction needed to
reposition a solar surface. Contact based adjustment methods may be
used, but are prone to poor station alignment, mechanical fatigue,
and are difficult to seal from the installation environment. If
necessary, the robotic controller may use positive mechanical
engagement, friction, or suction based systems, for example, to
mechanically control the rotation of an adjustment wheel.
[0061] FIG. 4 shows one embodiment of a non-contact interface
between a robotic controller and an adjustment wheel (102). This
system uses individually controlled electromagnets (401) to rotate
a metallic adjustment wheel. The adjustment wheel may have a
distinct metallic form (402) that enables certain electromagnetic
coil firing patterns to alter its degree of rotation. Other
systems/embodiments may utilize permanent magnets on the adjustment
wheel and/or permanent magnets on the robotic controller (301).
Systems that utilize a permanent magnet or contact based adjustment
interface may be connected to a rotational drive system in order to
rotate the adjustment wheel. Systems that utilize electromagnets on
the robotic controller side may be solid state. In many embodiments
adjustment interfaces using electricity to control the rotation of
an adjustment wheel use electromagnets, and it is most effective
from an energy usage and system lifetime perspective to reduce the
adjustment interface to a simple axial flux or induction motor
wherein the expensive components are contained on the robotic
controller.
[0062] FIG. 4 also shows that a robotic controller may contain a
system to detect the orientation of an adjustment wheel before,
after, and during adjustment. These systems may utilize one or more
sensors (403) to detect the position of a distinct marking (404) on
the adjustment wheel. Types of markings include, but are not
limited to magnetic or metallic materials, physical indents, or
markings that can be recognized by an optical, electromagnetic, or
electrostatic sensing mechanism. This system is useful because it
allows the robotic controller to verify that a solar surface has
been correctly repositioned by a distinct number of input
rotations. It also allows the robot to verify that the wheel has
not rotated between adjustments.
[0063] FIG. 5 depicts an overview of a robotic controller's
components in accordance with an embodiment of the present
invention. From this view it can be seen that the robot has idler
(501) and drive wheels (502) that keep it aligned and propel it
along an enclosed track. These idler wheels may be spring-loaded to
index the robotic controller to one or two sides of the track. The
robotic controller may also include a calibration camera (503) and
a structured light emission mechanism to discover the orientation
of a solar surface in 3D space. For systems/embodiments that
utilize an enclosed track, a window(s) or other opening transparent
to a particular frequency can be positioned in the track near a
solar surface. This window(s) allows a calibration camera to view
the underside of the solar surface. Puncturing a hole in the robot
transport tube may create this window. To enable the track to
remain sealed, a piece of glass, plastic, or other transparent
material may cover the hole.
[0064] To reposition a solar surface, the robotic controller must
be able to control the position of one or more adjustment wheels.
This may be accomplished through the use of an adjustment interface
that can include solid-state electromagnetic coils (401) that may
be activated/deactivated individually. Adjustment wheel rotation
sensors (403) may enable the robotic controller to determine the
instantaneous position of the adjustment wheel. Other components of
the robotic controller not depicted may include but are not limited
to an individual station detection unit, global or relative
location discovery unit, internal wiring, central processing unit,
motor driver controller, drive motor encoder, onboard climate
control system, battery management system, contact based charging
system, inductive charging system, distance proximity sensor, data
storage system, capacitor storage system for regenerative braking
purposes, and wireless data transmitter/receiver. The precise
placement of these components varies depending on the embodiment as
they can be housed in many configurations within the confines of a
robotic controller.
[0065] FIG. 6 shows the operational process of the robotic
controller in accordance with an embodiment of the present
invention. This operational process demonstrates how a single
robotic controller (301) may reposition a multiplicity of solar
surfaces (101). The functional duty of this robotic controller is
to work in conjunction with one or more adjustment wheels (102)
near a solar surface to properly maintain the orientation of an
individual solar surface.
[0066] When a robotic controller is first deployed, its initial
goal is to understand its environment and the passive
trackers/heliostats it will be controlling. This begins with the
robotic controller moving towards an adjustment wheel (601) and
continually searching for a braking point (602) placed near a solar
surface. This point could be an actual marking on the beam, a
magnet, or a piece of metal, for example. If there is an actual
marking on the beam, the robotic controller may be outfitted with a
camera to detect this point. If the braking point is magnetic or
metallic, the robotic controller may be outfitted with Hall effect
sensors or metal detection system to discover the braking point. In
one embodiment, the adjustment wheel or markers on the adjustment
wheel used for rotational sensing may be used as the braking point.
After the braking point has been detected, the robotic controller
may activate its braking mechanism (603). Methods of braking may
include but are not limited to: deactivation of the drive motor,
application of a wheel brake, application of a motor brake,
regenerative braking, or a hybrid of these braking mechanisms.
While the device is slowing down, the robotic controller searches
for the final adjustment point (604). Once this point has been
found, it applies a full brake and brings itself to a complete stop
(605).
[0067] After properly aligning itself to one or more adjustment
wheels, the robotic controller discovers its relative orientation
to the solar surface. If it is the first time that a robotic
controller has visited a particular solar surface adjustment
station, it may "zero" the solar surface by adjusting it to zero
degrees tilt and zero degrees of azimuthal rotation or another
defined setting. To achieve this goal, the robotic controller may
engage an adjustment wheel (606), and begin rotating it (607).
While rotating, it may use onboard adjustment wheel sensors (403)
to verify that the wheel is spinning properly (608). The solar
surface may have hard calibration stops that prevent it from being
rotated past the zero point. In these systems, the robotic
controller may stop trying to adjust the system once the wheel can
no longer be rotated (609). To prevent damage to a passive surface
or a gear train attached to a passive surface, a robotic
controller's adjustment wheel interface may include a mechanism
that prevents the system from delivering a damaging amount of
torque.
[0068] For applications that do not require much precision, the
robotic controller may use these stops and record the number of
adjustment wheel revolutions from an initial calibration point
during daily operation to estimate the current orientation of the
surface. For more precise applications, the robot may also use a
structured or natural light camera to analyze the underside of a
solar surface to determine its relative orientation in 3d space.
Once this information has been obtained, it is relayed to a central
processor for analysis.
[0069] Depending on the solar application, it may also be necessary
to find the absolute or relative location of the solar surface in
X, Y, and Z coordinates. This may be accomplished with an onboard
GPS unit with a triangulation system that utilizes three locations
in the field of solar surfaces. In this second method, the robotic
controller may emit a signal and measure the time delay from each
defined point in the field. Using this information, it may
determine its relative location to other components in the field of
solar surfaces.
[0070] The central processing may now analyze inputs from the
calibration camera, location discovery unit, internal clock, and
combine this with the known gear reduction of the passive solar
tracker/heliostat, and known field geometry (610). Inputs from the
robot's internal clock and discovered or known global location can
be used to calculate the current solar vector (611). Inputs from
the robot's calibration camera, location discovery unit, adjustment
wheel sensing mechanism, and/or historic adjustment information
from past adjustments can be used to approximate the orientation of
a solar surface in 3D space. In one embodiment, the passive solar
tracker or heliostat driven by the adjustment wheels has anti-back
drive properties. These systems only require a one-time calibration
as wind and other forces are unable to move the solar surface
between adjustments.
[0071] PV and CPV applications may use up to five pieces of
information for proper repositioning. The orientation of the solar
surface, the position of the sun, the orientation of adjacent
trackers, the distance between trackers, and the pre-defined
tracker area and dimensions of the solar surface. Standard solar
tracking algorithms may only require the first two pieces of
information, but the robot uses the other three to properly execute
backtracking control algorithms. These algorithms optimize a solar
field for minimal inter-tracker shading, and therefore understand
the shadows that are currently being generated by adjacent
trackers, and the shadow that an individual solar tracker will cast
on its neighbors. More details regarding backtracking are found at
Mack, Solar Engineering:
http:/www.rw-energy.com/pdf/yield-of-s_wheel-Almansa-graphics.pdf
which is incorporated by reference herein in its entirety.
[0072] Heliostat applications require the robot to discover the
vector from a solar surface to a solar target. This may be achieved
by finding the location of both the solar target and the solar
surface in a global or relative coordinate plane. Once the desired
change in solar surface orientation has been calculated, the
central processor analyzes a passive system's known gear reduction
to determine how many degrees it should rotate an adjustment wheel
linked mechanically or magnetically to the solar surface (612).
[0073] For passive trackers or heliostats that do not have inherent
friction braking or anti-back drive properties, an active solar
surface braking mechanism may be necessary. For these systems, the
robotic controller deactivates the brake prior to rotating the
adjustment wheel or wheels. This brake may be actuated with another
adjustment wheel. The robotic controller may then use its
adjustment wheel interface to rotate one or more adjustment wheels.
In one embodiment, the robotic controller has a multiplicity of
electromagnetic coils that can be activated individually or in
groups. This system is able to control the rotation of a metal or
magnetic adjustment wheel by firing the coils as an axial flux or
induction style motor (613). The coils may be fired blindly or may
obtain feedback from an adjustment wheel sensing mechanism that
determines the instantaneous degree of rotation of an adjustment
wheel (614).
[0074] Once adjustment is complete, the central processor may send
a signal to actuate the braking mechanism if necessary. This
re-engages the gear braking mechanism and prevents outside forces
from altering a solar surface's orientation until its next
adjustment from the robotic controller. As a final step of this
process, the robotic controller may use onboard proximity sensors
or past operational history to determine if it is currently at the
end of a row of solar surfaces (615). If yes, it may move backward
until it reaches the first solar surface adjustment point (616). If
no, the controller may repeat this adjustment cycle (617). Also
note that it is possible to connect the ends of a robot transport
tube such that it forms a continuous loop. In this embodiment,
robotic controller would continue circulating the robot transport
tube until nighttime or stopping for maintenance.
[0075] The processor that determines the behavior of the robotic
controller and its sub components could be located on the robotic
controller directly, at a central processing station, or on another
robotic controller in the field of solar surfaces. If the processor
is not onboard, the robotic controller may require a wireless or
direct data link to receive operational instructions.
[0076] After a day of adjusting solar surfaces, the robotic
controller may need to recharge its onboard energy storage
mechanism. It may also recharge this system two or more times
throughout the day.
[0077] It may be desirable for a field of solar surfaces to be
adjusted by three or more grades of robotic controllers. FIG. 6
demonstrates the operational process of a top grade robotic
controller. This robot may work in conjunction with less
sophisticated robotic controllers. A purpose of the top grade
robotic controller is to permit the removal of the location
discovery unit and calibration camera from both the mid and low
grade robotic controllers. In an embodiment, a field of solar
surfaces may only use one top grade robotic controller (if any) and
could therefore greatly reduce total system and robotic controller
replacement costs by removing expensive components from the
unit.
[0078] FIG. 7 shows the operational process of a less
sophisticated, mid grade robotic controller in accordance with an
embodiment of the present invention. The main difference between
this unit and the top grade robotic controller described in FIG. 6
is that this adjustor does not have a calibration camera or a
location discovery unit. The functional duties of the calibration
camera and the location discovery unit are assumed by a data
discovery unit that communicates with other robots or a central
control station, and a data storage unit that stores the last known
orientation of individual solar surfaces. When a mid grade robotic
controller first interacts with a passive solar surface and has no
prior data points, it may assume that the top grade robotic
controller has properly "zeroed" the solar surface.
[0079] Unlike a top grade robot, a mid-grade robotic controller
pulls its input for the adjustment point's location from a data
storage unit instead of a location discovery unit (701). It also
determines the relative orientation of a solar surface from an
onboard data storage unit and Hall effect sensors instead of a
precise calibration camera. The data storage unit stores the number
of adjustment wheel rotations from the zero point, and the
adjustment wheel sensing mechanism is used to determine the exact
degree of wheel rotation (702). Combined with known gear reduction
information, this data may be sufficient for the mid grade robotic
controller to approximate the orientation of a solar surface in 3D
space. As the mid grade robotic controller does not have a method
of determining the exact orientation of a solar surface directly,
it may save the degree of adjustment wheel rotation performed to
one or more adjustment wheels so that it may properly reorient a
solar surface in future adjustments.
[0080] After a day of adjusting solar surfaces, the robotic
controller may need to recharge its onboard energy storage
mechanism. It may also recharge this system two or more times
throughout the day.
[0081] FIG. 8 shows the operational process of a less
sophisticated, low-grade robotic controller in accordance with an
embodiment of the present invention. The purpose of a low-grade
robotic controller is similar to a spare tire for a car--it is to
be used only in emergency situations. This third class of robotic
controllers enables a low cost, and rapid wind stow procedure. It
also enables a high-speed emergency defocus procedure for heliostat
applications. This robotic controller may have a similar
operational process as the mid grade robotic controller described
in FIG. 7, but it may only require one adjustment interface to move
a passive solar tracker or heliostat to its wind stow position, and
would not need to be built for long lifetime.
[0082] During emergency procedures, the low-grade robotic
controller would not need to know the current position of a solar
surface, only that the solar surface must be either a) moved 2-5
degrees away from its current position or b) moved into a
horizontal wind stow position. It may have an onboard anemometer to
determine current wind speed or may be connected to a central
network that sends the low-grade robotic controller a signal to
initiate an emergency wind stow procedure (801). This procedure
begins with the robotic controller moving itself near an individual
solar surface, stopping near a solar surface's adjustment wheel
(605), and rotating the adjustment wheel a pre-defined number of
revolutions (802). It may also use an adjustment wheel sensing
mechanism (403) to determine if the adjustment wheel has stopped
rotating (614). If it has, this may indicate that the low-grade
robotic controller has driven the passive solar tracker or
heliostat into its wind stow hard stop.
[0083] The process for emergency defocus may be even simpler than
for emergency wind stow. As the purpose of this procedure is to
move a heliostat's image away from a solar target, the low-grade
robotic controller only needs to be able to quickly alter the
position of many solar surfaces.
[0084] FIG. 9 demonstrates some of the methods that could be used
by a field of robotic controllers to communicate with each other
and/or with a centralized network. These methods include, but are
not limited to: wireless data communication (901), direct data link
(902), external switches, or by storing information near individual
passive solar surfaces or groups of passive solar surfaces (903).
For wireless data communication, each robotic controller may be
equipped with an electromagnetic frequency transmitter and/or
receiver (904) that is able to communicate with other robots (301)
or a centralized network (905).
[0085] For direct data transfer, each robotic controller may be
equipped with contacts that can interact with contacts on other
robots or a centralized data unit. When these systems make physical
contact, data may be transferred from one device to another.
[0086] A human or robotic field operator may activate certain
features on a top, mid, or low-grade robot that correspond to
certain pre-programmed actions. Actuating an external, magnetic, or
electromagnetic switch may initiate these actions. For example, if
a low-grade robot has a pre-programmed emergency defocus feature, a
mid-grade robot may be able to activate it simply by running into
it and depressing a push button switch.
[0087] It is also useful to be able to store relevant data near
individual solar surfaces or groups of solar surfaces. In one
embodiment, an RFID chip (903) placed near a solar surface may be
used to store the information about each solar surface's absolute
or relative location in the field and how this corresponds to the
initial position of each adjustment wheel. These systems would
require individual robotic controllers to have an RFID writer
and/or RFID reader. Other methods of storing data locally include
but are not limited to using semiconductor, magnetic, and/or
optical based data storage technologies.
[0088] FIG. 10 shows a robotic controller (301) with multiple
adjustment wheel interfaces (302). The purpose of adding more
adjustment interfaces is to distribute the cost of the most
expensive onboard components and to allow for more precise control
of a solar surface (101) by permitting more frequent adjustments
over the same period of time. The depicted embodiment is able to
adjust two solar surfaces at one time; enabling this design to cut
the number of start-stop cycles for a given field of solar surfaces
in half.
[0089] FIG. 11 shows a robotic controller (301) that is able to
control adjustment wheels without stopping at an adjustment
station. This system may utilize a contact, magnetic, or
electromagnetic based gear rack and pinion system to control the
adjustment wheel. The robotic interface conceptually serves as the
gear rack (1101) and the adjustment wheel (102) as the pinion
(1102). As the robot drives past an adjustment wheel, it may
actuate its conceptual gear rack interface so that it
couples--physically, magnetically, or electromagnetically--with one
edge of an adjustment wheel. Once coupled, the linear motion of the
robotic controller may be turned directly into rotation of the
adjustment wheel. The robotic controller may actuate its interface
(1101) a second time to decouple itself from the adjustment wheel
pinion (1102). The robotic controller can precisely control the
rotation of an adjustment wheel by carefully monitoring its speed
and time that its adjustment interface is coupled with an
adjustment wheel. For example, if a robotic controller is moving at
1 meter per second and engages the edge of a 3.18 cm diameter
adjustment wheel (10 cm circumference) for 1 second, it will rotate
it approximately 10 times.
[0090] The robotic controller can utilize a long strip of sensors
(403) that measure the instantaneous degree of wheel rotation to
confirm that the adjustment wheel (102) has been engaged and is
spinning properly. A robotic controller that does not stop or make
physical contact with individual solar surfaces may accurately
reposition up to 1.2 MW of photovoltaic modules if moving at a
constant rate of 5 MPH.
[0091] The robotic controller depicted in FIG. 11 uses a long line
of individually actuated electromagnets (401) to control the
orientation of an adjustment wheel. When these electromagnets are
turned on in a (N-S-N-S-N-S) arrangement, they are able to rotate
4-pole magnetic adjustment wheel (N-S-N-S) simply by driving past
the adjustment station. This magnetic gear rack system turns linear
motion of the robot into rotational motion of the adjustment
wheel.
[0092] FIG. 12 shows how the robot transport tube (106) may be
routed in a field with a large number of solar surfaces (101). The
robot transport tube may be hermetically sealed to prevent large
object, water, and dust ingress into the robotic controller. In the
depicted embodiment, each passive solar tracker or heliostat has an
individual foundation and the robot transport tube only has to
support the weight of a robotic controller or controllers.
[0093] This figure demonstrates that while an individual robotic
controller may normally adjust a particular row of solar surfaces,
it can utilize an onboard drive motor to return itself to a central
station for maintenance (1201). This style of track routing also
enables a field operator easily deploy a field of robotic
controllers by inserting two or more of them into a central
station. This central station may also be used for charging or
maintenance purposes.
[0094] FIG. 12 also demonstrates that excess robotic controllers
(301) can be used redundantly. In one embodiment, one or more
backup robotic controllers are placed at the central station. In
the case of a robotic failure, a backup robotic controller can
drive itself into the proper section of track, push the failed
robot to the end of the tube and resume adjustment solar surfaces
assigned to the failed robot. If the failed robot was not
constantly relaying the position of its assigned solar surfaces to
a central data system, it may be necessary for the backup robot to
run an initial re-calibration process as outlined in FIG. 6. If
this information was accurately relayed to a central data system,
the backup robot may resume operation wherein the failed robot
stopped adjusting.
[0095] In the case that a field of solar surfaces does not have a
central robot collection system, two or more robots may be placed
into one section of track. These two or more robots may establish a
constant data transfer link. One robot may assume daily operation
(1202) while the other serves as a redundant robot (1203) to
prevent power loss due to failed controllers not being able to
properly reposition a solar surface's adjustment wheels.
[0096] FIG. 13 shows one embodiment of a climate control system for
the robotic controller (301). This system may comprise, but is not
limited to including the following components: fan (1301), heat
sink (1302), active heat pump, Peltier device, electric heater,
ventilation system, refrigerator, humidity control system, moisture
sensors, temperature sensors, and air filter. These climate control
components may also be offloaded onto a sealed robot transport tube
so that the system may maintain a consistent environment that
prolongs the life of the robotic controller's key failure
components.
[0097] It may be useful to use batteries, capacitors, super
capacitors, or other forms of energy storage to reduce installation
complexity and overall system cost as a single battery can replace
one mile of electrified track. FIG. 14 shows one embodiment of the
present invention that utilizes a wireless power transfer interface
to charge an energy storage mechanism onboard the robotic
controller. Wireless charging mechanisms may be desirable, as they
do not require exposed contacts to transmit power to a robotic
controller. It is not necessary, however, for the robotic
controller to have an onboard source of stored energy, and it could
be powered by an electrified rail system, or inductively by the
track.
[0098] An inductive charging station (1401) placed at any location
on the robot transport tube is able to transfer energy to the
robotic controller by generating an oscillating electromagnetic
field. An inductive coil loop (1402) placed on the robotic
controller (301) is able to capture this energy and store it within
an onboard energy storage mechanism. Other forms of power transfer
that could be utilized by the robotic controller include, but are
not limited to: electrostatic induction, electromagnetic radiation,
and electrical conduction.
[0099] FIG. 15 shows the operational process of a robotic
controller's onboard diagnostic and quality assurance system. A
robotic controller may continuously perform aspects of this process
to enable a field or remote operator to determine a field's
instantaneous health. This process in its entirety or certain
aspects of this process may also be initiated daily, weekly,
monthly, or as needed to enable field operators to perform
preventive maintenance of the system. In particular, a robotic
controller's diagnostic system may determine: a) the overall health
of an individual robotic controller as defined by the status of key
components (1501), b) the health of a robot transport tube (1502),
c) the health of a passive solar tracker or heliostat (1503), and
d) the health of an individual PV or CPV surface (1504).
[0100] This process may begin with the robotic controller relaying
all saved operational data to a central processing system or
network (1505). This data may include, but is not limited to:
historical temperature and moisture readings on internal and
external sensors, historic meteorological data from an on or
offsite monitoring system, historic current and voltage readings
from all onboard components, and SOC/SOS readings from an onboard
energy storage mechanism. The diagnostic system may then compare
this information to past operational data (1506) and to pre-defined
safe ranges of operation (1507). Analysis of irregularities may be
used to determine the current health of individual components
and/or to perform preventative maintenance of a robotic controller
(1508).
[0101] To determine the health of a robotic transport tube (1502),
the robotic controller may access data from onboard cameras or
proximity sensors that are able to inspect the physical features of
the track (1509). If any abnormalities are discovered, such as an
object protruding into the track, a large build up of dirt in one
section of track, a hive of insects, or a puncturing in the track
that allows foreign object ingress, the robotic controller may send
a signal to a field or remote operator (1510). A field or remote
operator may access a live video feed from the robotic controller's
camera in order to better assess a maintenance situation.
[0102] To determine the health of a passive solar tracker or
heliostat, a robotic controller may access the data log generated
from adjusting an individual tracker (1511). It may then access the
data log measuring the amount of input torque/current needed to
rotate an adjustment wheel (1512) and understand how this metric
changes over time. If the robot uses an electromagnetic interface,
this torque metric can be determined by recording the average
current delivered to the interface over the course of an
adjustment. In one example, if the diagnostic system recognizes
that a passive solar tracker that usually requires 95 +/-5 amps
suddenly begins requiring 320 +/-20 amps to adjust during normal
operating conditions, it may deem this individual passive tracker
to be dysfunctional and send an alert a field maintenance worker
(1513). The robotic controller may also use vision-based systems to
inspect and analyze the health of an individual solar tracker or
heliostat. This video input may be relayed directly to a field
operator to assess the health of the tracking system. If a passive
tracker's torque/current readings are within an acceptable range,
this portion of the process (1503) may be repeated for every
passive surface (101) under a robot's control domain.
[0103] To autonomously determine the health of an individual PV or
CPV surface (1504), the robotic controller may first move an
individual tracker into its optimal orientation (1515). It may then
communicate with a device that is able to monitor the power output
of a central inverter, combiner box, or individual string of solar
modules (1516). As it is possible that in the robotically
controlled system that only one module in a group of modules may be
actuated at a single moment in time, the power output reading
should remain relatively constant. Once a data link has been
established, the robot may execute a search algorithm (1517) where
it moves the passive surface in a spiral while monitoring system
output. It may then record the maximum power point (1518) and
adjust the tracker so that it is no longer facing the sun (1519).
The diagnostic system may measure the change in central inverter,
combiner box, or string level output (1520). This information can
be used to determine the degradation percentage of an individual
module by measuring the exact difference in central inverter,
combiner box, or string level output and comparing this to a
module's rated output (1521) to calculate degradation percentage
(1522). If no change is detected, this may indicate that an
individual solar surface (101) is not contributing to the PV or CPV
system's total output. This module may be classified as defective
and the robotic controller may use its adjustment interface to
place this surface in a special configuration as to alert field
maintenance workers of the potential problem (1523). If the
degradation percentage is within an acceptable range, sub process
1504 may be repeated for all surfaces under a robot's control
domain (1524).
[0104] The robotic controller may also include pre-programmed
algorithms and security features to protect itself from theft
and/or reverse engineering. Onboard controllers and data storage
units may be encrypted to prevent access to control protocols and
data stored on the robot. In addition, there may be sensors that
detect unauthorized access to the robot, including attempts to open
a robotic controller. The controller may respond to such actions by
notifying a remote operator and/or erasing the control algorithms
and operational data. At the time of deployment, each robot may be
initialized with its deployment location and unique identification
number. If the robot, field operator, or remote operator detects
that the robot is no longer in the assigned location, then an
appropriate action may be taken to retrieve the lost or stolen
robotic controller.
[0105] While particular embodiments and applications of the present
invention have been illustrated and described herein, it is to be
understood that the invention is not limited to the precise
construction and components disclosed herein and that various
modifications, changes, and variations may be made in the
arrangement, operation, and details of the methods and apparatuses
of the present invention without departing from the spirit and
scope of the invention.
* * * * *
References