Automated solar arrays

Abstract

A photovoltaic system (10) is provided for use on the Earth over a surface (28). The photovoltaic system (10) includes a solar array (20) including one or more solar panels (24); and one or more supports (26), which are configured to be supported by the Earth, and to support the solar array (20) over the surface (28). A robot (100) is suspended from the solar array (20) below the solar array (20), and configured to move along the solar array (20). Other embodiments are also described.

Description

[0001] AUTOMATED SOLAR ARRAYS

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] The present application claims priority from US Provisional Application 63 / 448,058, filed February 24, 2023, which is assigned to the assignee of the present application and incorporated herein by reference.

[0004] FIELD OF THE APPLICATION

[0005] The present invention relates generally to solar arrays.

[0006] BACKGROUND OF THE APPLICATION

[0007] Agrivoltaics is the use of agricultural fields for both agriculture and photovoltaic generation of power by placement of photovoltaic arrays over fields. Agrivoltaics enables efficient use of scarce land, and may provide synergistic benefits by providing beneficial shade to certain crops. In addition, the generated electricity may be used for performing agricultural operations on the crops and / or field.

[0008] Agricultural robotics automate agricultural functions, such as harvesting, sowing, spraying, pruning, weeding, and environmental monitoring.

[0009] SUMMARY OF THE APPLICATION

[0010] In some embodiments of the present invention, a photovoltaic (PV) system comprises a solar array and one or more supports, which are configured to be supported by the Earth, and to support the solar array over a surface, such as of a field (e.g., an agricultural field) or a body of water. Typically, the PV system is configured to tilt the solar array as the sun moves across the sky throughout the day, which may allow optimization of the collection of sunlight and / or control of the location of shadows cast by the solar array on the surface and / or on plants, such as trees or crops.

[0011] In some applications of the present invention, the PV system further comprises a robot, which is typically an agricultural robot configured to perform one or more agricultural operations, such as harvesting, sowing, spraying, pruning, weeding, and environmental monitoring. The robot is coupled to, mechanically supported by, and configured to move along the solar array. For example, the robot may be suspended from the solar array below the solar array, and configured to move along the solar array. In some applications, an end effector of the robot is configured to perform one or more operations at one or more sites away from the solar array.

[0012] For some applications, the solar array comprises a track, and the robot is configured to move along the track when coupled to the track. For example, the track may be located at an edge of the solar array.

[0013] For some applications, the solar array is movable with respect to the surface, so as to move the robot with respect to the surface, in order to reposition the robot at a target location, even while the robot may remain stationary along the solar array. For example, the solar array may be tiltable with respect to the surface, so as to move the robot with respect to the surface. Such tilting may also move the robot laterally.

[0014] In some applications of the present invention, the PV system comprises first and second PV rows, which comprise first and second solar arrays, respectively. The robot is configured to move from being suspended below the first solar array to being suspended below the second solar array and vice versa.

[0015] In some applications of the present invention, the one or more supports comprise a set of two or more columns, which are configured to be supported by the Earth; a main support coupled between the columns; and a plurality of hangers. The hanger suspend the solar array from the main support, such that (a) the columns are in compression and the main support is in tension, and (b) the entire solar array is movable in an arcuate path about an axis that is parallel to a longer dimension of the solar array and located away from the solar array such that the one or more solar panels face the axis. Movement of the entire solar array in the arcuate path tilts the solar array from side to side in a hammock-like hanging motion.

[0016] For some applications, the main support comprises a main suspension cable. The hangers typically comprise suspender cables or rods, as is known in the non-solar suspension bridge art.

[0017] There is therefore provided, in accordance with an application of the present invention, a photovoltaic system for use on the Earth over a surface, the photovoltaic system including: a solar array including one or more solar panels; one or more supports, which are configured to be supported by the Earth, and to support the solar array over the surface; and a robot, which is suspended from the solar array below the solar array, and configured to move along the solar array.

[0018] For some applications, the robot includes an end effector that is configured to perform one or more operations at one or more sites away from the solar array.

[0019] For some applications: the one or more supports are configured to support the solar array over the surface facing at least partially upward, and the end effector that is configured to perform the one or more operations at one or more sites below the solar array.

[0020] There is further provided, in accordance with an application of the present invention, a photovoltaic system for use on the Earth over a surface, the photovoltaic system including: a solar array including one or more solar panels; one or more supports, which are configured to be supported by the Earth, and to support the solar array over the surface; and a robot, which (a) is coupled to, mechanically supported by, and configured to move along the solar array, and (b) includes an end effector that is configured to perform one or more operations at one or more sites away from the solar array.

[0021] For some applications: the one or more supports are configured to support the solar array over the surface facing at least partially upward, and the end effector that is configured to perform the one or more operations at one or more sites below the solar array.

[0022] For some applications, the robot is suspended below the solar array.

[0023] For some applications: the surface is an agricultural field, and the one or more supports are configured to support the solar array over the agricultural field, and the robot includes an agricultural robot, which includes an end effector configured to perform one or more agricultural operations. For some applications, the one or more agricultural operations include one or more operations selected from the group consisting of: harvesting, sowing, spraying, pruning, weeding, and environmental monitoring.

[0024] There is still further provided, in accordance with an application of the present invention, a photovoltaic system for use on the Earth over an agricultural field, the photovoltaic system including: a solar array including one or more solar panels; one or more supports, which are configured to be supported by the Earth, and to support the solar array over the agricultural field; and a robot, which (a) is coupled to, mechanically supported by, and configured to move along the solar array, and (b) includes an agricultural robot including an end effector configured to perform one or more agricultural operations.

[0025] For some applications, the one or more agricultural operations include one or more operations selected from the group consisting of: harvesting, sowing, spraying, pruning, weeding, and environmental monitoring.

[0026] For some applications, the solar array includes a track, and the robot is configured to move along the track when coupled to the track.

[0027] For some applications, the track is located at an edge of the solar array.

[0028] For some applications, the solar array has longer and shorter dimensions perpendicular to a depth, and the edge is a longer edge of the solar array.

[0029] For some applications: the track is a first track, and the solar array further includes a second track, and the robot is configured to move along the first and the second tracks when coupled to the first and the second tracks.

[0030] For some applications, the photovoltaic system further includes a support that is configured to move along the first and the second tracks when coupled to the first and the second tracks, and couples the robot to the first and the second tracks.

[0031] For some applications: the solar array has longer and shorter dimensions perpendicular to a depth, and two longer edges parallel to the longer dimension, and the track is located away from the longer edges.

[0032] For some applications: the solar array defines a center line, which is parallel to the longer dimension and divides the solar array into first and second lateral portions, and the track runs along the center line.

[0033] For some applications, the solar array has longer and shorter dimensions perpendicular to a depth, and the longer dimension is greater than 2 times the shorter dimension.

[0034] For some applications, the solar array is movable with respect to the surface, so as to move the robot with respect to the surface in order to reposition the robot at a target location.

[0035] For some applications, the solar array is tiltable with respect to the surface, so as to move the robot with respect to the surface.

[0036] For some applications, the photovoltaic system further includes: one or more motors; and motor control circuitry configured to actuate the one or more motors to move the solar array with respect to the surface in order to reposition the robot at the target location.

[0037] For some applications, the photovoltaic system further includes robot control circuitry, which is configured to direct motion of the robot along the solar array.

[0038] For some applications, the one or more supports include: a set of two or more columns, which are configured to be supported by the Earth; a main support coupled between the columns; and a plurality of hangers, which suspend the solar array from the main support over the surface.

[0039] For some applications, the plurality of hangers suspend the solar array from the main support, such that (a) the columns are in compression and the main support is in tension, and (b) the entire solar array is movable in an arcuate path about an axis that is parallel to the longer dimension and located away from the solar array such that the one or more solar panels face the axis.

[0040] For some applications: the solar array is a first solar array, and the one or more solar panels are one or more first solar panels, the one or more supports are one or more first supports, and the first solar array and the one or more first supports are arranged in a first photovoltaic row, the photovoltaic system further includes a second photovoltaic row, which is arranged at least partially alongside the first photovoltaic row, and includes a second solar array including one or more second solar panels, and one or more second supports configured to support the second solar array over the surface, and the robot is configured to move from being suspended below the first solar array to being suspended below the second solar array and vice versa.

[0041] For some applications: the first solar array includes one or more first-array tracks and the second solar array includes one or more second-array tracks, and the robot is configured to move along the one or more first-array tracks and the one or more second-array tracks, when coupled to the first and the second tracks, respectively, the photovoltaic system further includes one or more linking tracks, which link together the one or more first-array tracks and the one or more second-array tracks, and the robot is configured to move from being coupled to the first solar array to being coupled to the second solar array and vice versa via the one or more linking tracks.

[0042] For some applications: the solar array is a first solar array, and the one or more solar panels are one or more first solar panels, the photovoltaic system further includes a second solar array including one or more second solar panels, the first and the second solar arrays are disposed at first and second respective heights with respect to each other, and the photovoltaic system further includes an elevator, which is configured to transport the robot between the first solar array and the second solar array, by: facilitating receipt of the robot from one of the first and the second solar arrays, changing a height of the robot, and facilitating delivery of the robot to the other of the first and the second solar arrays. For some applications: the one or more supports are one or more first supports, and wherein the first solar array and the one or more first supports are arranged in a first photovoltaic row, the photovoltaic system further includes a second photovoltaic row, which is arranged at least partially alongside the first photovoltaic row, and includes the second solar array, and one or more second supports configured to support the second solar array over the surface, the robot is configured to move from being suspended below the first solar array to being suspended below the second solar array and vice versa, and the first and the second photovoltaic rows are disposed at first and second respective heights with respect to each other.

[0043] For some applications, the first and the second solar arrays and the one or more supports are arranged in a photovoltaic row.

[0044] There is additionally provided, in accordance with an application of the present invention, a photovoltaic system for use on the Earth, the photovoltaic system including: a set of two or more columns, which are configured to be supported by the Earth; a main support coupled between the columns; a solar array, which has longer and shorter dimensions perpendicular to a depth, and includes one or more solar panels; and a plurality of hangers, which suspend the solar array from the main support, such that (a) the columns are in compression and the main support is in tension, and (b) the entire solar array is movable in an arcuate path about an axis that is parallel to the longer dimension and located away from the solar array such that the one or more solar panels face the axis.

[0045] For some applications, the axis is perpendicular to the columns.

[0046] For some applications, an average distance of the axis from the one or more solar panels is equal to at least 50% of the shorter dimension.

[0047] For some applications, the average distance of the axis from the one or more solar panels is equal to at least 100% of the shorter dimension.

[0048] For some applications: the solar array defines a center line, which is parallel to the longer dimension and divides the solar array into first and second lateral portions, and

[0049] (a) a first plane defined by the axis and the center line forms a right angle with (b) a second plane defined by the one or more solar panels.

[0050] For some applications: the solar array defines a center line, which is parallel to the longer dimension and divides the solar array into first and second lateral portions, and

[0051] (a) a first plane defined by the axis and the center line forms a predetermined oblique angle with (b) a second plane defined by the one or more solar panels.

[0052] For some applications: the hangers (a) are coupled to the solar array at respective solar-array coupling sites, (b) are coupled to the main support at respective main-support coupling sites, and (c) have respective lengths between the respective solar-array coupling sites and the respective main-support coupling sites, and the lengths of the hangers remain constant during motion of the entire solar array in the arcuate path.

[0053] For some applications, the photovoltaic system further includes one or more hanger supports, the hangers are coupled to the main support via the one or more hanger supports.

[0054] For some applications, the main support includes a beam.

[0055] For some applications, the longer dimension is greater than 2 times the shorter dimension.

[0056] For some applications, the main support is coupled to the columns at respective coupling sites on the columns, the coupling sites collectively defining the axis.

[0057] For some applications, at least one of the columns includes a fixed portion and a moveable portion configured to move relative to the fixed portion with at least one degree of freedom.

[0058] For some applications, the degree of freedom is a vertical degree of freedom, such that movement of the moveable portion relative to the fixed portion changes a height of the main support with respect to the Earth. For some applications, the degree of freedom is a rotational degree of freedom, such that movement of the moveable portion relative to the fixed portion changes a height and a horizontal position of the main support with respect to the Earth.

[0059] For some applications: the solar array is a first solar array, and the one or more solar panels are one or more first solar panels, the photovoltaic system further includes a second solar array including one or more second solar panels, the first and the second solar arrays are disposed at first and second respective heights with respect to each other, and the photovoltaic system further includes: a robot, which is configured to move along the first and the second solar arrays; and an elevator, which is configured to transport the robot between the first solar array and the second solar array, by: facilitating receipt of the robot from one of the first and the second solar arrays, changing a height of the robot, and facilitating delivery of the robot to the other of the first and the second solar arrays.

[0060] For some applications: the set of two or more columns is a first set of two or more first columns, the main support is a first main support, the plurality of hangers is a plurality of first hangers, and wherein the arcuate path is a first arcuate path about a first axis, the first set of first columns, the first main support, the first solar array, the first one or more solar panels, and the plurality of first hangers are arranged in a first photovoltaic row, and the photovoltaic system further includes a second photovoltaic row, which is arranged at least partially alongside the first photovoltaic row, and includes: a second set of two or more second columns, which are configured to be supported by the Earth; a second main support coupled between the second columns; the second solar array, which has longer and shorter dimensions perpendicular to a depth; and a plurality of second hangers, which suspend the second solar array from the second main support, such that (a) the second columns are in compression and the second main support is in tension, and (b) the entire second solar array is movable in an arcuate path about a second axis that is parallel to the longer dimension of the second solar array and located away from the second solar array such that the second solar panels face the axis, and wherein the first and the second photovoltaic rows are disposed at first and second respective heights with respect to each other.

[0061] For some applications, the set of two or more columns, the main support, the first and the second solar arrays, and the plurality of hangers are arranged in a photovoltaic row.

[0062] For some applications, the arcuate path is a solar-array arcuate path, and the main support includes a main suspension cable, which moves in a suspension-cable arcuate path during motion of the entire solar array in the solar-array arcuate path.

[0063] For some applications, the hangers are coupled directly to the main suspension cable.

[0064] For some applications, the photovoltaic system further includes one or more hanger supports, the hangers are coupled to the main suspension cable via the one or more hanger supports.

[0065] For some applications, the photovoltaic system further includes two secondary suspension cables, which are coupled to the main suspension cable and the hangers.

[0066] For some applications: the solar array defines a center line, which is parallel to the longer dimension and divides the solar array into first and second lateral portions, and some of the hangers are coupled to the first lateral portion of the solar array, and some of the hangers are coupled to the second lateral portion of the solar array.

[0067] For some applications: the first and the second lateral portions of the solar array define first and second longer edges of the solar array, and some of the hangers are coupled to the first longer edge of the solar array, and some of the hangers are coupled to the second longer edge of the solar array.

[0068] For some applications, all of the hangers that are coupled to the solar array other than at short ends of the solar array are coupled to the solar array at either the first longer edge or the second longer edge.

[0069] For some applications, all of the hangers that are coupled to the solar array other than at short ends of the solar array are coupled to the solar array at coupling sites located away from the center line.

[0070] For some applications: the set of two or more columns is a first set of two or more first columns, the main support is a first main support, the solar array is a first solar array, the one or more solar panels are first one or more solar panels, the plurality of hangers is a plurality of first hangers, and the arcuate path is a first arcuate path about a first axis, the first set of first columns, the first main support, the first solar array, the first one or more solar panels, the plurality of first hangers are arranged in a first photovoltaic row, and the photovoltaic system further includes a second photovoltaic row, which is arranged at least partially alongside the first photovoltaic row, and includes: a second set of two or more second columns, which are configured to be supported by the Earth; a second main support coupled between the second columns; a second solar array, which has longer and shorter dimensions perpendicular to a depth, and includes one or more second solar panels; and a plurality of second hangers, which suspend the second solar array from the second main support, such that (a) the second columns are in compression and the second main support is in tension, and (b) the entire second solar array is movable in an arcuate path about a second axis that is parallel to the longer dimension of the second solar array and located away from the second solar array such that the second solar panels face the axis.

[0071] For some applications, the photovoltaic system further includes one or more pull cables that are coupled to the first solar array and are coupled to one or more of the second columns, respectively, such that pulling on the one or more pull cables toward the one or more of the second columns moves the entire first solar array in the first arcuate path.

[0072] For some applications: the one or more pull cables are one or more first pull cables, and the photovoltaic system further includes a third photovoltaic row, which is arranged at least partially alongside the second photovoltaic row, and includes: a third set of two or more third columns, which are configured to be supported by the Earth; a third main support coupled between the third columns; a third solar array, which has longer and shorter dimensions perpendicular to a depth, and includes one or more third solar panels; and a plurality of third hangers, which suspend the third solar array from the third main support, such that (a) the third columns are in compression and the third main support is in tension, and (b) the entire third solar array is movable in an arcuate path about a third axis that is parallel to the longer dimension of the third solar array and located away from the third solar array such that the one or more third solar panels face the axis.

[0073] For some applications, the photovoltaic system further includes one or more second pull cables that are coupled to the second solar array and are coupled to one or more of the third columns, respectively, such that pulling on the one or more second pull cables toward the one or more of the third columns moves the entire second solar array in the second arcuate path, such that torque applied to the one or more second columns by the pulling of the one or more first pull cables is at least partially offset by torque applied to the second solar array by the pulling by the one or more second cables.

[0074] For some applications: the photovoltaic system further includes a third photovoltaic row, which is arranged at least partially alongside the second photovoltaic row, and includes: a third set of two or more third columns, which are configured to be supported by the Earth; a third main support coupled between the third columns; a third solar array, which has longer and shorter dimensions perpendicular to a depth, and includes one or more third solar panels; and a plurality of third hangers, which suspend the third solar array from the third main support, such that (a) the third columns are in compression and the third main support is in tension, and (b) the entire third solar array is movable in an arcuate path about a third axis that is parallel to the longer dimension of the third solar array and located away from the third solar array such that the one or more third solar panels face the axis. the photovoltaic system further includes: a gear, fixed with respect to the second column; a cable engaged by the gear, and coupled to the first and the third solar arrays; one or more motors, coupled to the gear, and the gear and the cable are arranged to move the entire first solar array, the entire second solar array, and the entire third solar array in the respective arcuate paths about the respective axes upon rotation of the gear by the one or more motors so as to pull the cable.

[0075] For some applications, the photovoltaic system further includes an inter-row rod that connects the first, the second, and the third solar arrays, so as to transmit the arcuate motion of the first and the third photovoltaic rows to the second photovoltaic row.

[0076] For some applications, the photovoltaic system further includes one or more motors, which are configured to move the entire solar array in the arcuate path about the axis.

[0077] For some applications, the photovoltaic system is configured to convert rotational motion of the one or more motors to move the entire solar array in the arcuate path about the axis.

[0078] For some applications: the photovoltaic system further includes a curved rack and a pinion, one of which is fixed with respect to one of the columns, and the other of which is fixed with respect to the solar array, the one or more motors are coupled to pinion, and the curved rack and the pinion are arranged to move the entire solar array in the arcuate path about the axis upon rotation of the pinion by the one or more motors.

[0079] For some applications, the photovoltaic system further includes: first and second gears, disposed on opposite longer sides of the solar array, and fixed with respect to the one or more columns;

[0080] For some applications: the photovoltaic system further includes: first and second gears, disposed on opposite longer sides of the solar array, and fixed with respect to the one or more columns; and a cable engaged by the first and the second gears, and coupled to the solar array, the one or more motors are coupled to the first and the second gears, and the first and the second gears and the cable are arranged to move the entire solar array in the arcuate path about the axis upon rotation of one of the first and the second gears by one or more of the motors so as to pull the cable in a respective direction.

[0081] For some applications: the photovoltaic system further includes first and second auxiliary columns, disposed on opposite longer sides of the solar array, the first and the second gears are fixed with respect to the first and the second auxiliary columns, respectively.

[0082] The present invention will be more fully understood from the following detailed description of embodiments thereof, taken together with the drawings, in which:

[0083] BRIEF DESCRIPTION OF THE DRAWINGS

[0084] Figs. 1A-B are schematic illustrations of a photovoltaic (PV) system, in accordance with an application of the present invention;

[0085] Figs. 2A-C are schematic illustrations of the PV system of Figs. 1A-B having solar arrays thereof oriented in three respective orientations with respect to a surface, in accordance with an application of the present invention;

[0086] Figs. 3A-B are schematic illustrations of the PV system of Figs. 1A-B, in accordance with an application of the present invention;

[0087] Fig. 4 is a schematic cross-sectional illustration of a single solar array of the PV system of Figs. 1A-B oriented in the three orientations of Figs. 2A-C, respectively, in accordance with an application of the present invention; Figs. 5A-C are schematic illustrations of a configuration of the PV system of Figs. 1A-B having solar arrays thereof oriented in three respective orientations with respect to the surface, in accordance with an application of the present invention;

[0088] Figs. 6A-B are schematic illustrations of another configuration of the PV system of Figs. 1A-B having solar arrays thereof oriented in two respective orientations with respect to the surface, in accordance with an application of the present invention;

[0089] Figs. 7A-C are schematic illustrations of yet another configuration of the PV system of Figs. 1A-B having solar arrays thereof oriented in three respective orientations with respect to the surface, in accordance with an application of the present invention;

[0090] Fig. 8 is a highly schematic illustration of an alternative arrangement of hangers and a main support of the PV system of Figs. 1A-B, in accordance with an application of the present invention;

[0091] Figs. 9A-C are schematic illustrations of the PV system of Figs. 1A-B comprising a robot, in accordance with an application of the present invention;

[0092] Fig. 10 is a schematic illustration of the PV system of Figs. 9A-C while a solar array thereof is in a tilted orientation with respect to the surface, in accordance with an application of the present invention;

[0093] Fig. 11 is a schematic illustration of two robots performing agricultural operations, in accordance with respective applications of the present invention;

[0094] Fig. 12 is a highly schematic illustration of an alternative arrangement of a track of the PV system of Figs. 9A-C, in accordance with an application of the present invention;

[0095] Figs. 13A-B are schematic illustrations of a portion of another configuration of the PV system of Figs. 1A-B, in two respective positions, in accordance with an application of the present invention;

[0096] Figs. 14A-B are schematic illustrations of a portion of yet another configuration of the PV system of Figs. 1A-B, in two respective positions, in accordance with an application of the present invention;

[0097] Figs. 15A-C are schematic illustrations of a portion of still another configuration of the PV system of Figs. 1A-B, in three respective positions, in accordance with an application of the present invention; Figs. 16A-C are schematic illustrations of a portion of the configuration of the PV system of Figs. 15A-C, having solar arrays thereof oriented in three respective orientations with respect to a surface, in accordance with an application of the present invention;

[0098] Figs. 17A-H are schematic illustrations of a portion of another configuration of the PV system of Figs. 1A-B, in accordance with an application of the present invention;

[0099] Figs. 18A-E are schematic illustrations of a portion of yet another configuration of the PV system of Figs. 1A-B, in accordance with an application of the present invention;

[0100] Figs. 19A-B are schematic illustrations of a technique for detecting an orientation of a ground-based robot with respect to a solar array, in accordance with an application of the present invention;

[0101] Figs. 20A-B are schematic illustrations of a technique for detecting a location of a ground-based robot with respect to a centerline of a surface plane, in accordance with an application of the present invention; and

[0102] Fig. 21 is a schematic illustration of another photovoltaic (PV) system, in accordance with an application of the present invention.

[0103] DETAILED DESCRIPTION OF APPLICATIONS

[0104] Figs. 1A-B are schematic illustrations of a photovoltaic (PV) system 10, in accordance with an application of the present invention. Fig. 1A shows PV system 10 from above and to the side, and Fig. IB is a top view of PV system 10.

[0105] Reference is further made to Figs. 2A-C, which are schematic illustrations of PV system 10 having solar arrays 20 thereof oriented in three respective orientations with respect to a surface 28, in accordance with an application of the present invention. Fig. 2A shows solar arrays 20 oriented horizontally with respect to surface 28, while Figs. 2B and 2C show solar arrays 20 tilted in opposite directions with respect to surface 28.

[0106] Reference is still further made to Figs. 3A-B, which are schematic illustrations of PV system 10, in accordance with an application of the present invention.

[0107] Reference is additionally made to Fig. 4, which is a schematic cross-sectional illustration of a single solar array 20 of PV system 10 oriented in the three orientations of Figs. 2A-C, respectively, in accordance with an application of the present invention. PV system 10 comprises one or more photovoltaic (PV) rows 22, arranged at least partially alongside one another. By way of example and not limitation, in the configuration shown in Figs. 1A-B and 2A-C, PV system 10 comprises PV rows 22A, 22B, and 22C.

[0108] Each PV row 22 comprises:

[0109] • a solar array 20, which has a longer dimension D (a length) and a shorter dimension Dg (a width) (labeled in Fig. IB) both perpendicular to a depth, and comprises one or more solar panels 24 (labeled in Fig. 2A); and

[0110] • one or more supports 26 (labeled in Fig. 2A), which are configured to be supported by the Earth, and to support solar array 20 over surface 28, such as of a field (e.g., an agricultural field) or a body of water.

[0111] For some applications, each PV row 22 comprises a plurality of solar arrays 20 arranged in series, such as shown and labeled in Fig. IB for solar arrays 20-1 and 20-2 of PV row 22A, by way of example. Generally, a single one of solar arrays 20 of each PV row 22 is described herein, although any additional solar arrays 20 of a given PV row 22 may also have the various characteristics described herein.

[0112] In configurations in which PV system 10 is deployed over an agricultural field, PV rows 22 may be deployed over rows of crops or trees or between rows of crops or trees. Optionally, one PV row 22 is provided for each N rows of crops or trees, such as for each 2 rows of crops or trees. Alternatively, PV rows 22 are deployed with no particular arrangement with respect to the crops or trees.

[0113] For some applications, the one or more supports 26 comprise:

[0114] • a set of two or more columns 30 (labeled in Fig. 2A), which are configured to be supported by the Earth (which optionally may be surface 28, such as shown);

[0115] • a main support 32 coupled between columns 30 (labeled in Fig. 2A); and

[0116] • a plurality of hangers 36, which suspend solar array 20 from main support 32, such that (a) columns 30 are in compression and main support 32 is in tension, and (b) the entire solar array 20 is movable in an arcuate path 40 about an axis 42 (labeled in Figs. 1A and 4) that is parallel to the longer dimension DL (labeled in Fig. IB) and located away from solar array 20 such that the one or more solar panels 24 face axis 42. Arcuate path 40 is typically a continuous portion of a curve, such as a continuous portion of a circle (i.e., a circular arc).

[0117] Typically, axis 42 remains stationary, even during motion of the entire solar array 20 in arcuate path 40.

[0118] Typically, the entire solar array 20 is movable in arcuate path 40 about a single axis 42.

[0119] For some applications, the plurality of hangers 36 suspend solar array 20 from main support 32, such that when columns 30 are in compression and main support 32 is in tension, the entire solar array 20 is movable only in arcuate path 40 about axis 42.

[0120] For some applications, hangers 36 suspend solar array 20 from main support 32 such that motion of the entire solar array 20 is restricted to a single degree of freedom in arcuate path 40 about axis 42.

[0121] Movement of the entire solar array 20 in arcuate path 40 tilts solar array 20 from side to side in a hammock-like hanging motion. Tilting of solar array 20 as the sun moves across the sky throughout the day may allow:

[0122] • optimization of the collection of sunlight,

[0123] • control of the location of shadows (shade) cast by solar array 20 on surface 28 (e.g., an agricultural field) and / or on plants, such as trees or crops, and / or

[0124] • balancing optimization of the collection of sunlight with the location of shadow.

[0125] Alternatively or additionally, solar array 20 may be tilted in order to move robot 100, as described hereinbelow with reference to Figs. 9A-C and 10.

[0126] For some applications, the two or more columns 30 are oriented vertical to the Earth. Optionally, such as shown in Fig. 2B, all or a portion of the two or more columns 30 are supported by guy wires 82 that are coupled to the Earth and columns 30, in order to stabilize the columns.

[0127] Optionally, PV system 10 comprises one or more cables that couple solar arrays 20 to surface 28, such as in order to reduce the effect of wind on the solar arrays. For some applications, main support 32 comprises a main suspension cable 54, such as shown. For other applications, main support 32 comprises a beam (configuration not shown).

[0128] Hangers 36 typically comprise suspender cables or rods, as is known in the nonsolar suspension bridge art.

[0129] For some applications, axis 42 is perpendicular to columns 30, such as shown in the figures. Alternatively, axis 42 is angled with respect to columns 30, such that axis 42 intercepts each of columns 30 at a different height from the Earth (configuration not shown). This latter configuration may be useful for orienting the one or more solar panels 24 with respect to the sun, depending on the horizontal direction in which PV rows 22 are oriented.

[0130] Typically, but not necessarily, the two or more columns 30 are oriented vertically with respect to the Earth.

[0131] Typically, but not necessarily, axis 42 is generally parallel with surface 28.

[0132] For some applications, such as labeled in Fig. 1A, main support 32 is coupled to columns 30 at respective coupling sites 31 on columns 30, and coupling sites 31 collectively define axis 42.

[0133] For some applications, main suspension cable 54 is a continuous cable.

[0134] For some applications, each of solar arrays 20 is supported by exactly two columns 30, such as shown. (Optionally, one of columns 30 can be the member of two sets of columns of the same PV row 22, such as shown.) For other applications, each of solar arrays 20 is supported by three or more columns 30 (configuration not shown).

[0135] For some applications, each PV row 22 comprises three or more columns 30, such as shown. Alternatively, each PV row 22 comprises exactly two columns 30 (configuration not shown).

[0136] For some applications, the longer dimension DL is greater than 2 times the shorter dimension Dg, such as greater than 5 times the shorter dimension Dg, e.g., greater than 10 times the shorter dimension Dg.

[0137] For some applications, an average distance of axis 42 from the one or more solar panels 24 is equal to at least 50% of the shorter dimension Dg, such as at least 100%, e.g., at least 150%, of the shorter dimension Dg. (The average distance of axis 42 from the one or more solar panels 24 will depend in part on the tension applied to main suspension cable 54 and / or hangers 36; the greater the tension, the shorter the average distance.)

[0138] For some applications, as labeled in Figs. 2B and 4, solar array 20 defines a center line 44, which is parallel to the longer dimension DL and divides solar array 20 into first and second lateral portions 46A and 46B.

[0139] For some of these applications, such as labeled in Fig. 4, (a) a first plane 48A defined by axis 42 and center line 44 forms a right angle with (b) a second plane 48B defined by the one or more solar panels 24. This orientation is also shown in Figs. 1A-B and 2A-C, although not labeled.

[0140] Alternatively, for some of these applications, (a) first plane 48A defined by axis 42 and center line 44 forms a predetermined oblique angle with (b) second plane 48B defined by the one or more solar panels 24 (configuration not shown). In these applications, the predetermined oblique angle is typically formed even when solar array 20 is in a resting state, in which no force is applied to tilt the array.

[0141] For some applications, such as labeled in Fig. 2 A, hangers 36:

[0142] • are coupled to solar array 20 at respective solar-array coupling sites 50,

[0143] • are coupled to main support 32 at respective main-support coupling sites 52, and

[0144] • have respective lengths between the respective solar-array coupling sites 50 and the respective main-support coupling sites 52.

[0145] The lengths of hangers 36 remain constant during motion of the entire solar array in arcuate path 40 (labeled in Fig. 4). In other words, hangers 36 do not experience linear displacement during motion of the entire solar array 20 in arcuate path 40.

[0146] For some applications in which main support 32 comprises main suspension cable 54, arcuate path 40 is a solar-array arcuate path 40, and main suspension cable 54 moves in a suspension-cable arcuate path 56 during motion of the entire solar array in the solar-array arcuate path 40, such as labeled in Fig. 4.

[0147] For some applications, such as labeled in Figs. 2B and 4, some of hangers 36 are coupled to first lateral portion 46A of solar array 20, and some of hangers 36 are coupled to second lateral portion 46B of solar array 20. For some of these applications, the first and the second lateral portions 46 A and 46B of solar array 20 define first and second longer edges 60A and 60B of solar array 20. Some of hangers 36 are coupled to first longer edge 60A of solar array 20, and some of hangers 36 are coupled to second longer edge 60B of solar array 20.

[0148] For some of these applications, all of hangers 36 that are coupled to solar array 20 other than at short ends 62 of solar array 20 (labeled in Fig. 2B) are coupled to solar array 20 at either first longer edge 60A or second longer edge 60B. Optionally, in these applications, one or more of hangers 36 are additionally coupled to one or both short ends 62 of solar array 20 (configuration not shown).

[0149] For some applications, all of hangers 36 that are coupled to solar array 20 other than at short ends 62 of solar array 20 are coupled to solar array 20 at coupling sites located away from center line 44, such as shown in the figures. Optionally, in these applications, one or more of hangers 36 are additionally coupled to one or both short ends 62 of solar array 20 at and / or away from center line 44 (configuration not shown).

[0150] For other applications, some or all of hangers 36 that are coupled to solar array 20 other than at short ends 62 of solar array 20 are coupled to solar array 20 at coupling sites on center line 44 (configuration not shown).

[0151] For some applications, as highly schematically shown in Fig. 2B, PV system 10 comprises one or more motors 64, which are configured to move the entire solar array 20 in arcuate path 40 about axis 42. For some of these applications, PV system 10 further comprises motor control circuitry 65, which is configured to actuate the one or more motors 64 to move the entire solar array 20 in arcuate path 40.

[0152] Reference is again made to Fig. 2B. For some applications, PV system 10 comprises guy wires 82 that are coupled to the Earth and columns 30, in order to stabilize the columns.

[0153] Reference is now made to Figs. 5A-C, which are schematic illustrations of a configuration of PV system 10 having solar arrays 20 thereof oriented in three respective orientations with respect to surface 28, in accordance with an application of the present invention.

[0154] Reference is further made to Figs. 6A-B, which are schematic illustrations of another configuration of PV system 10 having solar arrays 20 thereof oriented in two respective orientations with respect to surface 28, in accordance with an application of the present invention.

[0155] Reference is still further made to Figs. 7A-C, which are schematic illustrations of yet another configuration of PV system 10 having solar arrays 20 thereof oriented in three respective orientations with respect to surface 28, in accordance with an application of the present invention.

[0156] In all three of the configurations shown in Figs. 5A-C, 6A-B, and 7A-C, PV system 10 may be configured to convert rotational motion of the one or more motors 64 to move the entire solar array 20 in arcuate path 40, and, optionally, in configurations in which PV system 10 comprises a plurality of PV rows 22, to move the respective of plurality of entire solar arrays 20 in respective arcuate paths 40.

[0157] In the configuration shown in Figs. 5A-C, PV system 10 further comprises a curved rack 66 and a pinion 68, one of which is fixed with respect to one of columns 30, and the other of which is fixed with respect to solar array 20. In the illustrated configuration, curved rack 66 is fixed with respect to solar array 20 (e.g., one of short ends 62 of solar array 20), and pinion 68 is fixed with respect to one of columns 30. Alternatively, curved rack 66 is fixed with respect to one of columns 30, and pinion 68 is fixed with respect to solar array 20 (configuration not shown).

[0158] Motor 64 is coupled to pinion 68. Curved rack 66 and pinion 68 are arranged to move the entire solar array 20 in in arcuate path 40 about axis 42 (labeled in Fig. 4) upon rotation of pinion 68 by motor 64.

[0159] Optionally, respective motors 64, curved racks 66, and pinions 68 are provided at both short ends 62 of solar array 20 (configuration not shown).

[0160] For some of these applications, each PV row 22 comprises its own respective motor(s) 64, curved rack(s) 66, and pinion(s) 68, such as shown in Figs. 5A-C.

[0161] Alternatively, for some of these applications, fewer than all PV rows 22 comprise motor(s) 64, curved rack(s) 66, and pinion(s) 68. Solar arrays 20 of adjacent PV rows 22 are connected by an inter-row rod 70, which transmits arcuate motion of the motorized PV row(s) 22 to the non-motorized PV row(s) 22. Inter-row rod 70 is not shown in Figs. 5A- C, but can be implemented as shown in Figs. 6A-B, mutatis mutandis. For some of these applications in which each PV row 22 comprises a plurality of solar arrays 20 arranged in series, such as shown and labeled in Fig. 1A, each of solar arrays in a given PV row 22 comprises its own respective motor(s) 64, curved rack(s) 66, and pinion(s) 68.

[0162] In the configuration shown in Figs. 6A-B, PV system 10 typically comprises at least first, second, and third PV rows 22A, 22B, and 22C. PV system 10 further comprises a gear 72 (e.g., a round gear) and a cable 74 engaged by gear 72. gear 72 is fixed with respect to one of columns 30, typically of second PV row 22B. Cable 74 is coupled to solar arrays 20 of two of PV rows 22, such to solar arrays 20A and 20C of PV rows 22A and 22C.

[0163] Motor 64 is coupled to gear 72. Gear 72 and cable 74 are arranged to move the entire first, second, and third solar arrays 20A, 20B, and 20C in respective arcuate paths 40 about respective axes 42 upon rotation of gear 72 by motor 64 so as to pull cable 74.

[0164] Typically, solar arrays 20 of adjacent PV rows 22 are connected by an inter-row rod 70, which transmits arcuate motion of PV rows 22A and 22C (to which cable 74 is coupled) to PV row 22B (to which gear 72 is coupled). Optionally, in configurations in which PV system comprises more than three PV rows 22, inter-row rod 70 is connected to solar panel(s) 20 of the additional PV row(s) 22 to which cable 74 is not coupled.

[0165] For some applications, cable 74 is coupled to short ends 62 of solar arrays 20A and 20C.

[0166] For some applications, cable 74 is coupled to solar arrays 20A and 20C at respective center lines 44 of the solar arrays, such as shown.

[0167] Optionally, respective motors 64, gears 72, and cables 74 are provided at both short ends 62 of solar array 20 (configuration not shown).

[0168] For some of these applications in which each PV system 10 comprises a plurality of PV rows 22, PV system 10 is configured to provide separate control of the motion of each of the rows.

[0169] For some of these applications in which each PV row 22 comprises a plurality of solar arrays 20 arranged in series, such as shown and labeled in Fig. 1A for solar arrays 20- 1 and 20-2 of PV row 22A, each of solar arrays 20 in a given PV row 22 comprises its own respective motor(s) 64, gear (s) 72, and cable(s) 74. In the configuration shown in Figs. 7A-C, PV system 10 further comprises at least first and second gears 78A and 78B (e.g., round gears, which may comprise respective spools), and a cable 80 engaged by the gears. First and second gears 78 A and 78B are disposed on opposite longer sides of solar array 20, and fixed with respect to columns 30. Cable 80 is coupled to solar arrays 20 of PV rows 22. Optionally, two or more PV rows 22 are disposed between first and second gears 78 A and 78B, such as shown.

[0170] One or more motors 64 are coupled to first and second gears 78 A and 78B. First and second gears 78 A and 78B and cable 80 are arranged to move the entire solar arrays 20 in respective arcuate paths 40 about respective axes 42 upon rotation of one of first and second gears 78 A and 78B by one or more of the motors 64 so as to pull cable 80 in a respective direction.

[0171] For some applications, cable 80 is coupled to short ends 62 of solar arrays 20, such as shown.

[0172] For some applications, cable 80 is coupled to solar arrays 20 at respective center lines 44 of the solar arrays, such as shown.

[0173] For some applications, such as shown in Figs. 7A-C, PV system 10 comprises at least first and second auxiliary columns 76A and 76B, located on opposite sides of one or more PV rows 22. First and second gears 78A and 78B are fixed with respect to first and second auxiliary columns 76 A and 76B, respectively.

[0174] For other applications, the auxiliary columns are not provided, and first and second lateral support structures are instead provided, which extend laterally outward from one or more columns 30, typically without resting on the ground (configuration not shown).

[0175] Optionally, respective first and second auxiliary columns, gears, and cables are provided at both short ends 62 of solar array 20 (configuration not shown).

[0176] For some of these applications in which each PV row 22 comprises a plurality of solar arrays 20 arranged in series, such as shown and labeled in Fig. 1A, each of solar arrays in a given PV row 22 comprises its own respective first and second auxiliary columns, gears, and cables.

[0177] Reference is still made to Figs. 7A-C. For some applications, PV system 10 comprises guy wires 82 that are coupled to the Earth and first and second auxiliary columns 76 A and 76B, in order to stabilize the auxiliary columns.. For some applications in which PV system 10 comprises PV first and second rows 22A and 22B, PV system 10 further comprises one or more first pull cables that are coupled to first solar array 20A and are coupled to one or more of the columns 30 of second row 22B, respectively, such that pulling on the one or more first pull cables toward the one or more of the columns of second row 22B moves the entire first solar array 20A in a first arcuate path 40 (configuration not shown).

[0178] For some of these applications in which PV system 10 further comprises PV third row 22C, arranged at least partially alongside the second PV row 22B, PV system 10 further comprises one or more second pull cables that are coupled to second solar array 20B and are coupled to one or more of the columns of third row 22C, respectively, such that pulling on the one or more second pull cables toward the one or more of the columns of third row 22C moves the entire second solar array 20B in a second arcuate path, such that torque applied to the one or more columns of the second row 22B by the pulling of the one or more first pull cables is at least partially offset by torque applied to second solar array 20B by the pulling by the one or more second cables.

[0179] Reference is again made to Figs. 1A-B, 2A-C, 3A-B, and 4 and is further made to Fig. 8, which is a highly schematic illustration of an alternative arrangement of hangers 36 and main support 32, in accordance with an application of the present invention.

[0180] For some applications, hangers 36 are coupled directly to main support 32 (e.g., main suspension cable 54), such as shown in Figs. 1A-B, 2A-C, 3A-B, and 4.

[0181] For other applications, such as shown in Fig. 8, PV system 10 further comprises one or more hanger supports 230. Hangers 36 are coupled to main support 32 (e.g., main suspension cable 54) via the one or more hanger supports 230. Although only a single hanger support 230 is shown in Fig. 8, in this configuration PV system 10 typically comprises a plurality of hanger supports 230 arranged along main suspension cable 54, each of which supports a pair of hangers 36.

[0182] For some applications, hanger supports 230 are rigid.

[0183] For some applications, hanger supports 230 are triangular.

[0184] In some applications of the present invention, PV system 10 further comprises two secondary suspension cables, which run alongside and below main suspension cable 54, and are coupled to main suspension cable 54 and hangers 36 (configuration not shown). Reference is now made to Figs. 9A-C, which are schematic illustrations of PV system 10 comprising a robot 100, in accordance with an application of the present invention. The techniques of robot 100 may implemented in combination with any of the features of the configurations of PV system 10 described herein. PV system 10 optionally comprises a plurality of robots 100, such as shown by way of example in Fig. 2A. Alternatively, in some applications of the present invention, PV system 10 does not comprise any robots.

[0185] Reference is also made to Fig. 10, which is a schematic illustration of PV system 10 while a solar array 20 thereof is in a tilted orientation with respect to surface 28, in accordance with an application of the present invention.

[0186] As labeled in Figs. 9C and 10, robot 100 typically comprises an end effector 110, which is configured to interact with the environment, as is known in the robotic arts. Typically, robot 100 further comprises a robotic arm 112 comprises an end to which end effector 110 is coupled. Optionally, robot 100, such as robotic arm 112, comprises one or more joints, such as shown.

[0187] For some applications in which surface 28 is an agricultural field, robot 100 comprises an agricultural robot, and end effector 110 is configured to perform one or more agricultural operations. For example, the one or more agricultural operations may include one or more of the following operations: harvesting, sowing, spraying, pruning, weeding, and environmental monitoring. Robot 100 may be arranged to perform the one or more agricultural operations on crops or trees under or adjacent the solar array 20 to which the robot is coupled, and / or under the solar array 20 of an adjacent PV row 22.

[0188] In some applications of the present invention, robot 100 is coupled to, mechanically supported by, and configured to move along solar array 20. In some of these applications, robot 100 is suspended from solar array 20 below solar array 20, and configured to move along solar array 20. Robot 100 is typically configured to be movable along solar array 20 both when solar array 20 oriented horizontally with respect to surface 28 (e.g., agricultural field) and when solar array 20 is tilted with respect to surface 28.

[0189] In some of these applications, end effector 110 of robot 100 is configured to perform one or more operations at one or more sites away from solar array 20. For some of these applications, the one or more supports 26 are configured to support solar array 20 over surface 28 facing at least partially upward, and end effector 110 is configured to perform the one or more operations at one or more sites below solar array 20. Optionally, robot 100 is suspended below solar array 20.

[0190] In some applications of the present invention in which surface 28 is an agricultural field, robot 100 comprises an agricultural robot, and end effector 110 is configured to perform one or more agricultural operations. In these applications, robot 100 is not necessarily suspended from solar array 20 below solar array 20; robot 100 instead may be mechanically supported by solar array 20 alongside and / or above solar array 20.

[0191] Alternatively, for some applications, end effector 110 is of robot 100 is configured to serve solar array 20. These applications may include configurations in which robot 100 is suspended from solar array 20 below solar array 20.

[0192] For some applications, solar array 20 comprises a track 120, and robot 100 is configured to move along track 120 when coupled to track 120. Track 120 may be shaped as a rail.

[0193] For some of these applications, track 120 is located at an edge of solar array 20. For example, in configurations in which solar array 20 has longer dimension DL and shorter dimension Dg, both perpendicular to a depth Dj, the edge is a longer edge 60 of solar array 20.

[0194] For some applications, track 120 is a first track 120A, and solar array 20 further comprises a second track 120B. Robot 100 is configured to move along first and second tracks 120A and 120B when coupled to the first and the second tracks. For example, first and second tracks 120A and 120B may located at first and second longer edges 60A and 60B of solar array 20, respectively, such as shown in Figs. 9A-C and labeled in Fig. 2B.

[0195] Optionally, PV system 10 further comprises a robot support 128 that is configured to move along first and second tracks 120 A and 120B when coupled to the first and the second tracks, and that couples robot 100 to the first and the second tracks. For some applications, robot support 128 is motorized, so as to move along first and second tracks 120A and 120B. For other applications, one or both of first and second tracks 120A and 120B are motorized, so as to move robot support 128 along first and second tracks 120A and 120B. For other applications, track 120 is located away from longer edges 60, such as described hereinbelow with reference to Fig. 12.

[0196] For some applications, solar array 20 is movable with respect to surface 28, so as to move robot 100 with respect to surface 28 (e.g., in arcuate path 40), in order to reposition robot 100 at a target location, even while robot 100 may remain stationary along solar array 20. For example, such as described hereinabove with reference to Figs. 1A-4 and shown in Fig. 10, solar array 20 may be tiltable with respect to surface 28, so as to move robot 100 with respect to surface 28. Such tilting may also move robot 100 laterally, such as by moving track 120 laterally (such as by tilting solar array 20). Alternatively, solar array 20 is movable with respect to surface 28 by a technique other than the techniques described herein. In these applications, motor control circuitry 65 (labeled in Fig. 2B) may be configured to actuate the one or more motors 64 (labeled in Fig. 2B) to move solar array 20 with respect to surface 28.

[0197] As shown highly schematically in Fig. 9B, PV system 10 further comprises robot control circuitry 122, which is configured to direct motion of robot 100 along solar array 20. For example, robot control circuitry 122 may be located within robot 100, external to robot 100 (e.g., integrated with motor control circuitry 65), and / or partially within and partially external to robot 100. PV system 10 may comprise one or more processors that actuate motor control circuitry 65 and / or robot control circuitry 122 to control the movements and operations of robot 100.

[0198] Reference is still made to Figs. 9A-C and also made to Fig. 3B. In some applications, PV system 10 comprises first and second PV rows 22A and 22B, which comprise first and second solar arrays 20A and 20B, respectively. For some of these applications, robot 100 is configured to move from being suspended below first solar array 20A to being suspended below second solar array 20B and vice versa.

[0199] For some applications, PV system 10 or robot 100 is configured to connect electricity to a given PV row 22 only when robot 100 is suspended below the PV row, and to disconnect the electricity when the robot exits the PV row. For example, this can be done using a mechanical switch at the end and beginning of a row or by a controlled switch that the field control system activates. For some of these applications, such as labeled in Fig. 9B, first solar array 20A comprises one or more first-array tracks 120-1 (e.g., two, as shown), and second solar array 20B comprises one or more second-array tracks 120-2 (e.g., two, as shown). Robot 100 is configured to move along the one or more first- array tracks 120-1 and along the one or more second-array tracks 120-2, when coupled to first and second tracks 120A and 120B, respectively. PV system 10 further comprises one or more linking tracks 124 (labeled in Figs. 2A and 3B), which link together the one or more first-array tracks 120-1 and the one or more second-array tracks 120-2. Robot 100 is configured to move from being coupled to first solar array 20A to being coupled to second solar array 20B and vice versa via the one or more linking tracks 124. By way of example, Fig. 2A shows robot 100 moving along one of linking tracks 124.

[0200] For some applications, the one or more linking tracks 124 are curved and have respective first and second ends that are alignable with (and optionally couplable to) respective ends of the one or more first-array tracks 120-1 and the one or more second-array tracks 120-2, optionally only when both of solar arrays 20A and 20B are oriented horizontally with respect to surface 28, such as shown in Fig. 3B. Optionally, PV system 10 comprises one or more locks, which are configured to lock the one or more first-array tracks 120-1 and the one or more second-array tracks 120-2 with respect to the first and second ends of the one or more linking tracks 124.

[0201] Optionally, additional stationary solar panels 126 are coupled to the one or more linking tracks 124.

[0202] Reference is made to Fig. 11, which is a schematic illustration of two robots 100 performing agricultural operations, in accordance with respective applications of the present invention. For example, the robot 100 on left is shown spraying fruit 114, and the robot 100 on the right is shown harvesting (picking) fruit 114 and depositing the fruit in a container 116 (e.g., a basket).

[0203] For some applications, at least one ground-based robot is provided on surface 28 (e.g., the agricultural field) which is configured to move along surface 28 in coordination with movement of robot 100. Optionally, robot control circuitry 122 controls the ground- based robot, in order to coordinate its movement and / or operation with that of robot 100. For example: • container 116 may be borne by the ground -based robot,

[0204] • the ground-based robot may comprise a container (e.g., a tank) containing an agricultural liquid, such as a pesticide, and robot 100 may draw the liquid from the container and apply it (e.g., by spraying) to the crops or trees as the ground-based robot moves in coordination with movement of robot 100.

[0205] Reference is now made to Fig. 12, which is a highly schematic illustration of an alternative arrangement of track 120, in accordance with an application of the present invention. This configuration may optionally be implemented in combination with any of the configurations described herein, mutatis mutandis. In this configuration, track 120 is located away from longer edges 60. For example, track 120 may run along center line 44 (also labeled in Fig. 2B), either handing below solar array 20 (such as by a track support 232, such as shown), or directly connected to the solar array (configuration not shown). Track 120 may be shaped as a rail. (Track support 232 is typically stationary with respect to solar array 20.)

[0206] Reference is now made to Figs. 13A-B, which are schematic illustrations of a portion of another configuration of PV system 10, in two respective positions, in accordance with an application of the present invention.

[0207] Reference is further made to Figs. 14A-B, which are schematic illustrations of a portion of yet another configuration of PV system 10, in two respective positions, in accordance with an application of the present invention.

[0208] Reference is further made to Figs. 15A-C, which are schematic illustrations of a portion of still another configuration of PV system 10, in three respective positions, in accordance with an application of the present invention.

[0209] For clarity of illustration, only a single column 30 is shown in Figs. 13A-B, 14A-B, and 15A-C, while more than one column 30 is generally provided, such as shown in many of the other figures.

[0210] The configurations of PV system 10 shown in Figs. 13A-B, 14A-B, and 15A-C may be implemented in combination with any of the techniques described herein.

[0211] In the configurations of PV system 10 shown in Figs. 13A-B, 14A-B, and 15A-C, at least one of columns 30 comprises a fixed portion 300 and a moveable portion 302 configured to move relative to fixed portion 300 with at least one degree of freedom, such as exactly one degree of freedom. Typically, fixed portion 300 is fixed to surface 28. Typically, main support 32 is coupled to moveable portion 302; as a result, main support 32 (and axis 42, described hereinabove with reference to Figs. 1A and 4) is moveable with respect to fixed portion 300, and thus surface 28, with the at least one degree of freedom.

[0212] For some applications, only one of the two or more columns 30 that support a given solar array 20, and / or only one of the two or more columns 30 that support a given PV row 22, implements these relative-movement techniques, in which case the relative movement additionally results in changing of an angle between the longitudinal axis of the solar array 20 and / or PV row 22 and surface 28. For other applications, two or more of the two or more columns 30 that support a given solar array 20, and / or two or more of the two or more columns 30 that support a given PV row 22, implement these relative-movement techniques, in which case the relative movement may or may not result in changing of the angle between the longitudinal axis of the solar array 20 and / or PV row 22 and surface 28, depending on whether the two or more columns are moved by the same amount as one another.

[0213] For some applications, such as shown in Figs. 13A-B and 14A-B, the degree of freedom is a vertical degree of freedom, such that movement of moveable portion 302 relative to fixed portion 300 changes a height of main support 32 with respect to the Earth (and with respect to surface 28).

[0214] For some applications, such as shown in Figs. 15A-C, the degree of freedom is a rotational degree of freedom, such that movement of moveable portion 302 relative to fixed portion 300 changes a height and a horizontal position of main support 32 with respect to the Earth (and with respect to surface 28). For example, such as shown in Figs. 15A-C, moveable portion 302 may rotate relative to fixed portion 300 about an axis 304 that extends between the column 30 and an adjacent column 30 (not shown) in PV row 22. Optionally, moveable portion 302 is substantially disposed above axis 304.

[0215] Optionally, the techniques of Figs. 15A-C are combined with the techniques of Figs. 13A-B or Figs. 14A-B. Reference is made to Figs. 13A-B, 14A-B, and 15A-C. The displacement of main support 32 with respect to the Earth (and with respect to surface 28) affects the position of the shadow cast by solar array 20 on surface 28.

[0216] Typically, PV system 10 comprises a motor 306 that effects the movement of moveable portion 302 relative to fixed portion 300. For example, motor 306 may be disposed in or on column 30, such as shown in Figs. 13A-B, 14A-B, and 15A-C, or elsewhere (configuration not shown). For example, motor 306 may be disposed at least partially within fixed portion 300, such as shown in Figs. 13A-B; at least partially within moveable portion 302, such as shown in Figs. 14A-B; or between moveable portion 302 and fixed portion 300 outside of both portions, such as shown in Figs. 15A-C. For example, motor 306 may comprise a linear actuator, such as shown.

[0217] Reference is further made to Figs. 16A-C, which are schematic illustrations of a portion of the configuration of PV system 10 described hereinabove with reference to Figs. 15A-C, having solar arrays 20 thereof oriented in three respective orientations with respect to surface 28, in accordance with an application of the present invention. Figs. 16A-C show moveable portion 302 in the position relative to fixed portion 300 shown in Fig. 15A. Fig. 16B shows solar arrays 20 oriented horizontally with respect to surface 28, while Figs. 16A and 16C show solar arrays 20 tilted in opposite directions with respect to surface 28.

[0218] This configuration provides solar array 20 with two degrees of freedom with respect to surface 28: (1) main support 32 (and axis 42) can rotate about axis 304 (which is fixed with respect to surface 28, and (2) solar array 20 is movable in an arcuate path 40 about an axis 42. As a result, both the position of the shadow and the orientation of the panel can be controlled at the same time.

[0219] Reference is now made to Figs. 17A-H, which are schematic illustrations of a portion of another configuration of PV system 10, in accordance with an application of the present invention.

[0220] Reference is further made to Figs. 18A-E, which are schematic illustrations of a portion of yet another configuration of PV system 10, in accordance with an application of the present invention. Figs. 18A and 18C-E are perspective views, and Fig. 18B is a top view. For clarity of illustration, only portions of first and second PV rows 22A and 22B are shown in Figs. 17A-H, while more than two PV rows 22 may be provided, such as shown in many of the other figures. Similarly, for clarity of illustration, only first and second non-end columns 30A and 30B are shown in Figs. 18A-E, while end columns 30 are also generally provided, such as shown in many of the other figures; in addition, additional PV rows 22 are also generally provided, such as shown in many of the other figures.

[0221] The configurations of PV system 10 shown in Figs. 17A-H and 18A-E may be implemented in combination with each other, and / or with any of the other techniques described herein.

[0222] In the configurations shown in Figs. 17A-H and 18A-E, of PV system 10 further comprises an elevator 400, which is configured to transport robot 100 (typically, bidirectionally) between a first solar array 20D and a second solar array 20E that are disposed at first and second respective heights with respect to each other. Elevator 400 is configured to facilitate receipt of robot 100 from one of first and second solar arrays 20E and 20E, change a height of the robot (by either raising or lowering the robot), and facilitate delivery of the robot to the other of the first and the second solar arrays. Changing the height of the robot means changing a height of the entirely of the robot, rather than changing a height of end effector 110 or another part of the robot with respect to a base of the robot.

[0223] Elevator 400 may be connected to the first and the second solar arrays by respective track segments 402, such as shown in Figs. 17A-H, or directly to the first and the second solar arrays, such as shown in Figs. 18A-E. Typically, elevator 400 comprises one or more motors arranged to change the height of the robot.

[0224] For example, first and second solar arrays 20D and 20E may be disposed at first and second respective heights with respect to each other because surface 28 (e.g., a field, such as an agricultural field) is sloped between first and second solar arrays 20D and 20E. Alternatively, surface 28 is not necessarily sloped; for example, this could be due to lack of leveling of the ground, a local obstacle (such as a tree or a stone that requires one row to be taller), or different agricultural crops that require different panel collectors.

[0225] For some applications, elevator 400 comprises one or two tracks 420, to which robot 100 is couplable (two tracks 420 are shown in the figures). Elevator 400 is configured to change the height of the robot by changing the height of the one or two tracks 420 (i.e., by raising or lowering the one or two tracks).

[0226] For some applications, PV system 10 further comprises robot support 128, such as described hereinabove with reference to Figs. 9A-11. Robot support 128 is configured to move along (a) respective tracks 120 of first and second solar arrays 20D and 20E, (b) track segments 402, if provided, and (c) one or two tracks 420, if provided. Typically, in these applications, elevator 400 is configured to change the height of the robot by changing the height of robot support 128.

[0227] In the configuration shown in Figs. 17A-H, elevator 400 is an elevator 400A, and PV system comprises first and second PV rows 22A and 22B, which are disposed at first and second respective heights with respect to each other. First and second PV rows 22A and 22B comprise first and second solar arrays 20D and 20E, respectively. Thus, elevator 400A is configured to facilitate the receipt of robot 100 from one of first and second solar arrays 20E and 20E (and thus from one of first and second PV rows 22A and 22B), change a height of the robot (by either raising or lowering the robot), and facilitate the delivery of the robot to the other of the solar arrays (and thus to the other of the PV rows).

[0228] In the configuration shown in Figs. 18A-E, elevator 400 is an elevator 400B, and PV row 22 comprises first and second solar arrays 20D and 20E. First and second solar arrays 20D and 20E are disposed at first and second respective heights with respect to each other, such that PV row 22 has a non-uniform height. Thus, elevator 400A is configured to change the height of the robot (by either raising or lowering the robot) along PV row 22.

[0229] Reference is now made to Figs. 19A-B, which are schematic illustrations of a technique for detecting an orientation of a ground-based robot 500 with respect to a solar array 20, in accordance with an application of the present invention. This technique is performed by PV system 10, such as by a control unit of PV system 10, which may be configured in software and / or hardware to perform this technique. The control unit typically comprises one or more processors, memory, and input / output ports, such as provided by a conventional computer system.

[0230] Ground-based robot 500 is configured to move on surface 28 (e.g., the agricultural field), and may implement any techniques known in the robotic arts. PV system 10 is typically configured to perform the technique repeatedly as ground-based robot 500 moves on surface 28.

[0231] Optionally, ground-based robot 500 is implemented in combination with the techniques described herein, including, but not limited to, those described hereinabove with reference to Fig. 11.

[0232] Because the location of solar array 20 with respect to surface 28 is known, the detection of the orientation of ground-based robot 500 with respect to solar array 20 also provides the orientation of ground-based robot 500 with respect to surface 28, which, for simplicity's sake, is assumed to define a surface plane 506. For example, as illustrated, this technique may be used to detect the orientation of ground-based robot 500 with respect to a centerline 502 between two parallel solar arrays 20A, 20B in two respective PV rows 22A, 22B.

[0233] As described in detail hereinabove, PV system 10 is configured to move solar array 20 in in arcuate path 40 about axis 42. Because the angle y (gamma) between hangers 36 and columns 30 of PV row 22A, the height of columns 30 from surface plane 506, and the length of hangers 36 are known, PV system 10 can readily determine the location of a line defined by longer edge 60 of solar array 20, 20A, using simple trigonometry.

[0234] For some applications, ground-based robot 500 comprises a plurality of distance sensors 510, such as two distance sensors 510, as shown. For example, distance sensors 510 may comprise laser distance sensors, as are known in the distance sensor art. Distance sensors 510 are configured to measure a distance from ground-based robot 500 to longer edge 60 of solar array 20, 20A. For example, the distance sensors may detect the line at which the distance increases dramatically between the bottom of solar array 20, 20A and the sky. For example, distance sensors 510 may be disposed on opposite ends of a centerline of the robot, such as shown.

[0235] For some applications, the control unit of PV system 10 calculates two right triangles 520, each having the following edges and vertices (for the sake of clarity, labeled for only one of the triangles):

[0236] • a hypotenuse 522 between a location KI of one of the distance sensors 510 and a closest point K2 on longer edge 60 of solar array 20, 20A, a vertical first leg 524 between closest point K2 and a location K3 on surface plane

[0237] 506 directly below closest point K2, and

[0238] • a horizontal leg 526 between location K3 and location KI.

[0239] For each triangle 520, the vertical first leg 524 thus represents the height of longer edge 60 of solar array 20, 20A from surface plane 506), which is known based on the known dimensions columns 30 and hangers 36, and the angle y (gamma) between hangers 36 and columns 30 of PV row 22A. The length of hypotenuse 522 is measured using the distance sensor 510. Based on these two known lengths of right triangle 520, the control unit of PV system 10 calculates the length of horizontal leg 526 using the Pythagorean theorem.

[0240] As best seen in Fig. 19B, the control unit of PV system 10 calculates the angle 0 (theta) between:

[0241] • a centerline 530 of ground-based robot 500, between the two distance sensors 510 on the robot (and between the two locations KI), and

[0242] • a line 532 on surface plane 506 directly under longer edge 60 of solar array 20, 20A (and parallel to centerline 502).

[0243] Angle 0 (theta) is calculated based on (a) the difference 540 between the lengths of the two horizontal legs 526, and (b) a length of centerline 530 of ground-based robot 500, equal to the distance between distance sensors 510 on the robot (and between locations KI), as follows: tan 0 (theta) = difference 540 / length of centerline 530

[0244] Angle 0 (theta) thus represents the orientation of centerline 530 of ground-based robot 500 and centerline 502 of surface plane 506, as defined above. This orientation may be used to by the system to adjust the orientation of the robot.

[0245] Reference is now made to Figs. 20A-B, which are schematic illustrations of a technique for detecting a location of ground-based robot 500 with respect to centerline 502 of surface plane 506, in accordance with an application of the present invention. This technique is performed by PV system 10, such as by a control unit of PV system 10. Optionally, this technique is performed in combination with the technique described hereinabove with reference to Figs. 19A-B.

[0246] The technique is based on the following definitions: • LI equals the distance between solar array 20, 20A and axis 42, described hereinabove,

[0247] • L2 equals half of the width of solar array 20, 20A,

[0248] • L3 equals the distance between (a) a vertical plane 550 defined by columns 30 (perpendicular to surface plane 506), and (b) a centerline plane 552 that intersects centerline 502 and is perpendicular to surface plane 506,

[0249] • L4 equals the length of hangers 36 (assuming the hangers are attached to the longer edges of the solar array),

[0250] • L5 equals the length of the above-described hypotenuse 522 between the location KI of one of the distance sensors 510 and a closest point K2 on longer edge 60 of solar array 20, 20A,

[0251] • angle a (alpha) is the angle between vertical plane 550 defined by columns 30 and LI (angle a (alpha) changes over time), and

[0252] • angle P (beta) is the fixed angle between LI and L4.

[0253] Therefore:

[0254] • R1 can be calculated and / or extracted using the following equations: sin (a + P) = R1 / L4 ;

[0255] • R2 can be calculated and / or extracted using the following equations:

[0256] L5 = ; (Pythagorean theorem)

[0257] L30 - total length of column 30 h - The height of the edge of the panel

[0258] L4* cos(cr + ?) = L30— h h = L30— L4* cos(cr + (T) R2 = (L52- / i2)

[0259] Therefore, the distance A (delta) between location KI on ground-based robot 500 and centerline plane 552 can be calculated as follows:

[0260] L3 = R1 + R2 + A

[0261] A = L3 - R1 - R2

[0262] Reference is now made to Fig. 21, which is a schematic illustration of a photovoltaic (PV) system 620, in accordance with an application of the present invention. Photovoltaic (PV) system 620 comprises rows of solar panels 24, connected to a static construction based on support columns connected to the ground and connecting beams between the columns. The solar panels 24 are located higher than the agricultural growth below.

[0263] In the space between the panels and the agricultural crop, tracks (rails) 720A are connected to the construction. For some applications, PV system 620 comprises a motorized bridge 740 that rides on pairs of rails along the rows of panels (in a strip 726 between a first ends 722 of rails 720A and a second end 724 of rails 720A). PV system 620 further comprises a motorized cart 734 that moves on top of motorized bridge 740 across strip 726. Various end effectors can be connected to this cart 734, such as a sprayer, a robotic arm, a panel cleaning machine, or a camera.

[0264] At the end of the rows there are additional tracks (rails) 720B connected to the construction. A motorized cart (service robot) 732 rides on tracks 720B.

[0265] When a generic robot 734 needs to move from one strip 726 to another strip 726, the generic robot 734 moves to the end of a row and connects to a service robot 732, which moves the generic robot 734 to the next strip 726.

[0266] Optionally, the various end effectors have docking stations where they park when not in use.

[0267] Optionally, when generic robot 734 is required to replace or take a function, it connects to a service robot 732 which leads the generic robot to a parking position of the appropriate end effector application where the generic robot connects to the end effector.

[0268] Optionally, PV system 620 comprises one or more elevators 400, such as described hereinabove with reference to Figs. 17A-H and / or 18A-E. It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description.

Claims

CLAIMS1. A photovoltaic system for use on the Earth over a surface, the photovoltaic system comprising: a solar array comprising one or more solar panels; one or more supports, which are configured to be supported by the Earth, and to support the solar array over the surface; and a robot, which is suspended from the solar array below the solar array, and configured to move along the solar array.

2. The photovoltaic system according to claim 1, wherein the robot comprises an end effector that is configured to perform one or more operations at one or more sites away from the solar array.

3. The photovoltaic system according to claim 2, wherein the one or more supports are configured to support the solar array over the surface facing at least partially upward, and wherein the end effector that is configured to perform the one or more operations at one or more sites below the solar array.

4. A photovoltaic system for use on the Earth over a surface, the photovoltaic system comprising: a solar array comprising one or more solar panels; one or more supports, which are configured to be supported by the Earth, and to support the solar array over the surface; and a robot, which (a) is coupled to, mechanically supported by, and configured to move along the solar array, and (b) comprises an end effector that is configured to perform one or more operations at one or more sites away from the solar array.

5. The photovoltaic system according to claim 4, wherein the one or more supports are configured to support the solar array over the surface facing at least partially upward, and wherein the end effector that is configured to perform the one or more operations at one or more sites below the solar array.

6. The photovoltaic system according to claim 4, wherein the robot is suspended below the solar array.

7. The photovoltaic system according to any one of claims 1-6, wherein the surface is an agricultural field, and the one or more supports are configured to support the solar array over the agricultural field, and wherein the robot comprises an agricultural robot, which comprises an end effector configured to perform one or more agricultural operations.

8. The photovoltaic system according to claim 7, wherein the one or more agricultural operations include one or more operations selected from the group consisting of: harvesting, sowing, spraying, pruning, weeding, and environmental monitoring.

9. A photovoltaic system for use on the Earth over an agricultural field, the photovoltaic system comprising: a solar array comprising one or more solar panels; one or more supports, which are configured to be supported by the Earth, and to support the solar array over the agricultural field; and a robot, which (a) is coupled to, mechanically supported by, and configured to move along the solar array, and (b) comprises an agricultural robot comprising an end effector configured to perform one or more agricultural operations.

10. The photovoltaic system according to claim 9, wherein the one or more agricultural operations include one or more operations selected from the group consisting of: harvesting, sowing, spraying, pruning, weeding, and environmental monitoring.

11. The photovoltaic system according to any one of claims 1-6 and 9-10, wherein the solar array comprises a track, and wherein the robot is configured to move along the track when coupled to the track.

12. The photovoltaic system according to claim 11, wherein the track is located at an edge of the solar array.

13. The photovoltaic system according to claim 12, wherein the solar array has longer and shorter dimensions perpendicular to a depth, and wherein the edge is a longer edge of the solar array.

14. The photovoltaic system according to claim 11, wherein the track is a first track, and wherein the solar array further comprises a second track, andwherein the robot is configured to move along the first and the second tracks when coupled to the first and the second tracks.

15. The photovoltaic system according to claim 14, further comprising a support that is configured to move along the first and the second tracks when coupled to the first and the second tracks, and couples the robot to the first and the second tracks.

16. The photovoltaic system according to claim 11, wherein the solar array has longer and shorter dimensions perpendicular to a depth, and two longer edges parallel to the longer dimension, and wherein the track is located away from the longer edges.

17. The photovoltaic system according to claim 16, wherein the solar array defines a center line, which is parallel to the longer dimension and divides the solar array into first and second lateral portions, and wherein the track runs along the center line.

18. The photovoltaic system according to any one of claims 1-6 and 9-10, wherein the solar array has longer and shorter dimensions perpendicular to a depth, and the longer dimension is greater than 2 times the shorter dimension.

19. The photovoltaic system according to any one of claims 1-6 and 9-10, wherein the solar array is movable with respect to the surface, so as to move the robot with respect to the surface in order to reposition the robot at a target location.

20. The photovoltaic system according to claim 19, wherein the solar array is tiltable with respect to the surface, so as to move the robot with respect to the surface.

21. The photovoltaic system according to claim 19, further comprising: one or more motors; and motor control circuitry configured to actuate the one or more motors to move the solar array with respect to the surface in order to reposition the robot at the target location.

22. The photovoltaic system according to any one of claims 1-6 and 9-10, further comprising robot control circuitry, which is configured to direct motion of the robot along the solar array.

23. The photovoltaic system according to any one of claims 1-6 and 9-10, wherein the one or more supports comprise:a set of two or more columns, which are configured to be supported by the Earth; a main support coupled between the columns; and a plurality of hangers, which suspend the solar array from the main support over the surface.

24. The photovoltaic system according to claim 23, wherein the plurality of hangers suspend the solar array from the main support, such that (a) the columns are in compression and the main support is in tension, and (b) the entire solar array is movable in an arcuate path about an axis that is parallel to the longer dimension and located away from the solar array such that the one or more solar panels face the axis.

25. The photovoltaic system according to any one of claims 1-6 and 9-10, wherein the solar array is a first solar array, and the one or more solar panels are one or more first solar panels, wherein the one or more supports are one or more first supports, and wherein the first solar array and the one or more first supports are arranged in a first photovoltaic row, wherein the photovoltaic system further comprises a second photovoltaic row, which is arranged at least partially alongside the first photovoltaic row, and comprises a second solar array comprising one or more second solar panels, and one or more second supports configured to support the second solar array over the surface, and wherein the robot is configured to move from being suspended below the first solar array to being suspended below the second solar array and vice versa.

26. The photovoltaic system according to claim 25, wherein the first solar array comprises one or more first-array tracks and the second solar array comprises one or more second-array tracks, and wherein the robot is configured to move along the one or more first-array tracks and the one or more second-array tracks, when coupled to the first and the second tracks, respectively, wherein the photovoltaic system further comprises one or more linking tracks, which link together the one or more first-array tracks and the one or more second-array tracks, and wherein the robot is configured to move from being coupled to the first solar array to being coupled to the second solar array and vice versa via the one or more linking tracks.

27. The photovoltaic system according to any one of claims 1-6 and 9-10,wherein the solar array is a first solar array, and the one or more solar panels are one or more first solar panels, wherein the photovoltaic system further comprises a second solar array comprising one or more second solar panels, wherein the first and the second solar arrays are disposed at first and second respective heights with respect to each other, and wherein the photovoltaic system further comprises an elevator, which is configured to transport the robot between the first solar array and the second solar array, by: facilitating receipt of the robot from one of the first and the second solar arrays, changing a height of the robot, and facilitating delivery of the robot to the other of the first and the second solar arrays.

28. The photovoltaic system according to claim 27, wherein the one or more supports are one or more first supports, and wherein the first solar array and the one or more first supports are arranged in a first photovoltaic row, wherein the photovoltaic system further comprises a second photovoltaic row, which is arranged at least partially alongside the first photovoltaic row, and comprises the second solar array, and one or more second supports configured to support the second solar array over the surface, wherein the robot is configured to move from being suspended below the first solar array to being suspended below the second solar array and vice versa, and wherein the first and the second photovoltaic rows are disposed at first and second respective heights with respect to each other.

29. The photovoltaic system according to claim 27, wherein the first and the second solar arrays and the one or more supports are arranged in a photovoltaic row.

30. A photovoltaic system for use on the Earth, the photovoltaic system comprising: a set of two or more columns, which are configured to be supported by the Earth; a main support coupled between the columns; a solar array, which has longer and shorter dimensions perpendicular to a depth, and comprises one or more solar panels; anda plurality of hangers, which suspend the solar array from the main support, such that (a) the columns are in compression and the main support is in tension, and (b) the entire solar array is movable in an arcuate path about an axis that is parallel to the longer dimension and located away from the solar array such that the one or more solar panels face the axis.

31. The photovoltaic system according to claim 30, wherein the axis is perpendicular to the columns.

32. The photovoltaic system according to claim 30, wherein an average distance of the axis from the one or more solar panels is equal to at least 50% of the shorter dimension.

33. The photovoltaic system according to claim 32, wherein the average distance of the axis from the one or more solar panels is equal to at least 100% of the shorter dimension.

34. The photovoltaic system according to claim 30, wherein the solar array defines a center line, which is parallel to the longer dimension and divides the solar array into first and second lateral portions, and wherein (a) a first plane defined by the axis and the center line forms a right angle with (b) a second plane defined by the one or more solar panels.

35. The photovoltaic system according to claim 30, wherein the solar array defines a center line, which is parallel to the longer dimension and divides the solar array into first and second lateral portions, and wherein (a) a first plane defined by the axis and the center line forms a predetermined oblique angle with (b) a second plane defined by the one or more solar panels.

36. The photovoltaic system according to claim 30, wherein the hangers (a) are coupled to the solar array at respective solar-array coupling sites, (b) are coupled to the main support at respective main-support coupling sites, and (c) have respective lengths between the respective solar-array coupling sites and the respective main-support coupling sites, and wherein the lengths of the hangers remain constant during motion of the entire solar array in the arcuate path.

37. The photovoltaic system according to claim 30, further comprising one or more hanger supports, wherein the hangers are coupled to the main support via the one or more hanger supports.

38. The photovoltaic system according to claim 30, wherein the main support comprises a beam.

39. The photovoltaic system according to claim 30, wherein the longer dimension is greater than 2 times the shorter dimension.

40. The photovoltaic system according to claim 30, wherein the main support is coupled to the columns at respective coupling sites on the columns, the coupling sites collectively defining the axis.

41. The photovoltaic system according to any one of claims 30-40, wherein at least one of the columns comprises a fixed portion and a moveable portion configured to move relative to the fixed portion with at least one degree of freedom.

42. The photovoltaic system according to claim 41, wherein the degree of freedom is a vertical degree of freedom, such that movement of the moveable portion relative to the fixed portion changes a height of the main support with respect to the Earth.

43. The photovoltaic system according to claim 41, wherein the degree of freedom is a rotational degree of freedom, such that movement of the moveable portion relative to the fixed portion changes a height and a horizontal position of the main support with respect to the Earth.

44. The photovoltaic system according to any one of claims 30-40, wherein the solar array is a first solar array, and the one or more solar panels are one or more first solar panels, wherein the photovoltaic system further comprises a second solar array comprising one or more second solar panels, wherein the first and the second solar arrays are disposed at first and second respective heights with respect to each other, and wherein the photovoltaic system further comprises: a robot, which is configured to move along the first and the second solar arrays; andan elevator, which is configured to transport the robot between the first solar array and the second solar array, by: facilitating receipt of the robot from one of the first and the second solar arrays, changing a height of the robot, and facilitating delivery of the robot to the other of the first and the second solar arrays.

45. The photovoltaic system according to claim 44, wherein the set of two or more columns is a first set of two or more first columns, the main support is a first main support, the plurality of hangers is a plurality of first hangers, and wherein the arcuate path is a first arcuate path about a first axis, wherein the first set of first columns, the first main support, the first solar array, the first one or more solar panels, and the plurality of first hangers are arranged in a first photovoltaic row, and wherein the photovoltaic system further comprises a second photovoltaic row, which is arranged at least partially alongside the first photovoltaic row, and comprises: a second set of two or more second columns, which are configured to be supported by the Earth; a second main support coupled between the second columns; the second solar array, which has longer and shorter dimensions perpendicular to a depth; and a plurality of second hangers, which suspend the second solar array from the second main support, such that (a) the second columns are in compression and the second main support is in tension, and (b) the entire second solar array is movable in an arcuate path about a second axis that is parallel to the longer dimension of the second solar array and located away from the second solar array such that the second solar panels face the axis, and wherein the first and the second photovoltaic rows are disposed at first and second respective heights with respect to each other.

46. The photovoltaic system according to claim 44, wherein the set of two or more columns, the main support, the first and the second solar arrays, and the plurality of hangers are arranged in a photovoltaic row.

47. The photovoltaic system according to any one of claims 30-40, wherein the arcuate path is a solar-array arcuate path, and wherein the main support comprises a main suspension cable, which moves in a suspension-cable arcuate path during motion of the entire solar array in the solar-array arcuate path.

48. The photovoltaic system according to claim 47, wherein the hangers are coupled directly to the main suspension cable.

49. The photovoltaic system according to claim 47, further comprising one or more hanger supports, wherein the hangers are coupled to the main suspension cable via the one or more hanger supports.

50. The photovoltaic system according to claim 47, further comprising two secondary suspension cables, which are coupled to the main suspension cable and the hangers.

51. The photovoltaic system according to any one of claims 30-40, wherein the solar array defines a center line, which is parallel to the longer dimension and divides the solar array into first and second lateral portions, and wherein some of the hangers are coupled to the first lateral portion of the solar array, and some of the hangers are coupled to the second lateral portion of the solar array.

52. The photovoltaic system according to claim 51, wherein the first and the second lateral portions of the solar array define first and second longer edges of the solar array, and wherein some of the hangers are coupled to the first longer edge of the solar array, and some of the hangers are coupled to the second longer edge of the solar array.

53. The photovoltaic system according to claim 52, wherein all of the hangers that are coupled to the solar array other than at short ends of the solar array are coupled to the solar array at either the first longer edge or the second longer edge.

54. The photovoltaic system according to claim 51, wherein all of the hangers that are coupled to the solar array other than at short ends of the solar array are coupled to the solar array at coupling sites located away from the center line.

55. The photovoltaic system according to any one of claims 30-40, wherein the set of two or more columns is a first set of two or more first columns, the main support is a first main support, the solar array is a first solar array, the one or moresolar panels are first one or more solar panels, the plurality of hangers is a plurality of first hangers, and wherein the arcuate path is a first arcuate path about a first axis, wherein the first set of first columns, the first main support, the first solar array, the first one or more solar panels, and the plurality of first hangers are arranged in a first photovoltaic row, and wherein the photovoltaic system further comprises a second photovoltaic row, which is arranged at least partially alongside the first photovoltaic row, and comprises: a second set of two or more second columns, which are configured to be supported by the Earth; a second main support coupled between the second columns; a second solar array, which has longer and shorter dimensions perpendicular to a depth, and comprises one or more second solar panels; and a plurality of second hangers, which suspend the second solar array from the second main support, such that (a) the second columns are in compression and the second main support is in tension, and (b) the entire second solar array is movable in an arcuate path about a second axis that is parallel to the longer dimension of the second solar array and located away from the second solar array such that the second solar panels face the axis.

56. The photovoltaic system according to claim 55, further comprising one or more pull cables that are coupled to the first solar array and are coupled to one or more of the second columns, respectively, such that pulling on the one or more pull cables toward the one or more of the second columns moves the entire first solar array in the first arcuate path.

57. The photovoltaic system according to claim 56, wherein the one or more pull cables are one or more first pull cables, and wherein the photovoltaic system further comprises a third photovoltaic row, which is arranged at least partially alongside the second photovoltaic row, and comprises: a third set of two or more third columns, which are configured to be supported by the Earth; a third main support coupled between the third columns; a third solar array, which has longer and shorter dimensions perpendicular to a depth, and comprises one or more third solar panels; anda plurality of third hangers, which suspend the third solar array from the third main support, such that (a) the third columns are in compression and the third main support is in tension, and (b) the entire third solar array is movable in an arcuate path about a third axis that is parallel to the longer dimension of the third solar array and located away from the third solar array such that the one or more third solar panels face the axis.

58. The photovoltaic system according to claim 57, further comprising one or more second pull cables that are coupled to the second solar array and are coupled to one or more of the third columns, respectively, such that pulling on the one or more second pull cables toward the one or more of the third columns moves the entire second solar array in the second arcuate path, such that torque applied to the one or more second columns by the pulling of the one or more first pull cables is at least partially offset by torque applied to the second solar array by the pulling by the one or more second cables.

59. The photovoltaic system according to claim 55, wherein the photovoltaic system further comprises a third photovoltaic row, which is arranged at least partially alongside the second photovoltaic row, and comprises: a third set of two or more third columns, which are configured to be supported by the Earth; a third main support coupled between the third columns; a third solar array, which has longer and shorter dimensions perpendicular to a depth, and comprises one or more third solar panels; and a plurality of third hangers, which suspend the third solar array from the third main support, such that (a) the third columns are in compression and the third main support is in tension, and (b) the entire third solar array is movable in an arcuate path about a third axis that is parallel to the longer dimension of the third solar array and located away from the third solar array such that the one or more third solar panels face the axis, wherein the photovoltaic system further comprises: a gear, fixed with respect to the second column; a cable engaged by the gear, and coupled to the first and the third solar arrays; and one or more motors, coupled to the gear, andwherein the gear and the cable are arranged to move the entire first solar array, the entire second solar array, and the entire third solar array in the respective arcuate paths about the respective axes upon rotation of the gear by the one or more motors so as to pull the cable.

60. The photovoltaic system according to claim 59, further comprising an inter-row rod that connects the first, the second, and the third solar arrays, so as to transmit the arcuate motion of the first and the third photovoltaic rows to the second photovoltaic row.

61. The photovoltaic system according to any one of claims 30-40, further comprising one or more motors, which are configured to move the entire solar array in the arcuate path about the axis.

62. The photovoltaic system according to claim 61, wherein the photovoltaic system is configured to convert rotational motion of the one or more motors to move the entire solar array in the arcuate path about the axis.

63. The photovoltaic system according to claim 61, further comprising a curved rack and a pinion, one of which is fixed with respect to one of the columns, and the other of which is fixed with respect to the solar array, wherein the one or more motors are coupled to pinion, and wherein the curved rack and the pinion are arranged to move the entire solar array in the arcuate path about the axis upon rotation of the pinion by the one or more motors.

64. The photovoltaic system according to claim 61, further comprising first and second gears, disposed on opposite longer sides of the solar array, and fixed with respect to the one or more columns.

65. The photovoltaic system according to claim 61, further comprising: first and second gears, disposed on opposite longer sides of the solar array, and fixed with respect to the one or more columns; and a cable engaged by the first and the second gears, and coupled to the solar array, wherein the one or more motors are coupled to the first and the second gears, and wherein the first and the second gears and the cable are arranged to move the entire solar array in the arcuate path about the axis upon rotation of one of the first and the second gears by one or more of the motors so as to pull the cable in a respective direction.

66. The photovoltaic system according to claim 65,further comprising first and second auxiliary columns, disposed on opposite longer sides of the solar array, wherein the first and the second gears are fixed with respect to the first and the second auxiliary columns, respectively.

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