FIELD OF INVENTION
The invention relates to an automated programmable robotic solar panel cleaning system having a mobile solar panel cleaning robot.
BACKGROUND OF THE INVENTION & PRIOR ARTS
Solar parks are becoming more prevalent around the world and has an expected lifetime of 20 – 25 years. The maximum power generated by the solar panels during daytime depends on many factors such as shadow, snow, high temperatures, pollen, bird droppings, sea salt, dust and dirt but the main factor i.e. the accumulation of dust particles and debris on the surface of photovoltaic (PV) panels reduces the power output especially in arid, dusty environments. The accumulation of dust on the surface of the photovoltaic modules decreases the incoming irradiance to the cell and produces power losses. The common solution is to clean the modules with water, but in large-scale photovoltaic plants this task is often expensive, especially in those areas with water shortage. As a result of continuous soiling, a layer of dirt piles up on top of the glass of the solar panel reducing its transmittance and therefore decreasing the power output of the entire system. It is often difficult and dangerous to reach the solar panels and clean them manually with or without water. Hence, the present invention proposes an automated, programmable and mobile robotic system for cleaning the photovoltaic solar panel array.

Most mobile robots found in the prior art are limited to cleaning the surface of the solar panels with cleaning brushes and use an additional rails either mounted on the side of the solar panel rows or along with the solar panel rows to be used as guide rails for the robot to travel.
For example, the patent US 2013/0305474 A1 titled Solar Panel Cleaning System and Method, describes a system and method for cleaning rows of solar panels where each solar row has an upper edge elevated above ground level and a lower edge to provide an inclination of the solar row. A cleaning assembly cleans the solar panel surfaces. A support frame supports the cleaning assembly and enables upward and downward motion in the width and length directions of the solar row. Operation and movement of the cleaning assembly is controlled so as to clean a surface of the solar panels during downward movement. The cleaning assembly is preferably not operative during upward movement. During downward movement, the cleaning assembly removes dirt, debris and dust from the Surface of the solar panels and generates an air stream to blow off the dirt, debris, and dust. The system further includes a guide system for moving the cleaning assembly to align with successive solar panel rows.
The patent EP 2048455A2 titled Automatic solar panel cleaning system, comprises of longitudinal rails, cleaning brushes, a drive unit mounted with possibility of linear displacement along the longitudinal rails and provided with at least one motor element for the rotational actuation of the cleaning brushes and the movement of said cleaning

brushes, together with the drive unit, along the longitudinal rails, an electric control panel and a rain sensor for the automatic start-up of the drive unit. This system uses longitudinal rails for the robot to travel.
In patent US 2011/0094549 A1 titled cleaning system for solar panel, a cleaning system for Solar panels includes a number of solar cells and a transparent protection pane covering the Solar cells. The cleaning system includes a frame, a cleaning device, and an operating device. The frame includes a first sidewall and an opposite second sidewall facing away from the first sidewall. The cleaning device is affixed on the transparent protection panel. The operating device includes a motor, a pulley and a belt. The motor is affixed on one end of the first sidewall. The pulley is affixed on the other end of the first sidewall. The belt is wrapped around the rotating shaft of the motor and the pulley. The cleaning device includes an axle connected to the operating device and a washer provided on the axle. The cleaning device is driven by the operating device to clean the Solar panel. This system uses a frame as guide for the robot to travel.
All the above-mentioned prior art systems use a guide system for moving the cleaning assembly to align with successive solar panel rows or This system uses longitudinal rails for the robot to travel.
The present invention relates to an automated and programmable robotic solar panel cleaning system, consisting of a parking station and a mobile robot that travels laterally

on the edges of solar panels without the use of frame or rails as a guide for robot to travel along the row of the solar panels and cleans the top surface of solar panel without use of water or chemical.
OBJECTS OF THE INVENTION
Therefore, the object of the present invention is to propose an automated and programmable robotic solar panel cleaning system consisting of a parking station and a mobile robot that travels laterally on the edges of solar panel frame and cleans the top surface of solar panel without use of water or chemical.
Another object of the proposed invention is to develop a solar panel cleaning robot which does not require any external rails for the robot to travel in horizontal direction.
Another object of the proposed invention is to provide a mobile solar panel cleaning robot which cleans the top surface of the solar panel without the use of water or chemicals and does not cause any damage to the surface of the solar panel.
Another object of the proposed invention is to design mobile solar panel cleaning robot which cleans the top surface of a solar panel or plurality of solar panels mounted in an array i.e. string of solar panels, either in portrait or landscape arrangement.

Another object of the proposed invention is developing the mobile solar panel cleaning robot which operates on its own power source i.e. rechargeable batteries.
Another object of the proposed invention is arranging the mobile solar panel cleaning robot which parks itself at parking station for charging the on-board rechargeable batteries and protection against sunlight.
SUMMARY OF THE INVENTION
An automated and programmable robotic solar panel cleaning system consisting of a parking station and a mobile robot that travels laterally on the edges of solar panel frame and cleans the top surface of solar panel without use of water or chemical.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure-1 is a view of mobile solar panel cleaning robot mounted on a solar panel and parking station.
Figure-2 is a view of the frame of the mobile solar panel cleaning robot.
Figure-3 is a view of the bottom drive with belt of an embodiment of mobile solar panel cleaning robot.

Figure-4 and Figure-5 are the views of the bottom drive with motorized wheels of another embodiment of mobile solar panel cleaning robot.
Figure-6 is a view of the top drive with belt of an embodiment of mobile solar panel cleaning robot.
Figure-7 is a view of the top drive with motorized wheels of another embodiment of mobile solar panel cleaning robot.
Figure-8 is a view of the cleaning trolley with nylon brush of an embodiment mobile solar panel cleaning robot.
Figure-9 is a view of the cleaning trolley with microfiber chenille cloth of another embodiment mobile solar panel cleaning robot.
Figure-10 is a view of the parking station for parking the mobile robot.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION
The present invention relates to an invention of an automated and programmable robotic solar panel cleaning system wherein a mobile robot that can travel horizontally (X-

direction) on the edges of solar panel frame, a cleaning device that can travel vertically (Y-direction), cleaning the accumulated dust on the top surface of solar panel, without use of any fluid such as water or without use of any chemical. Further, the mobile robot parks itself at a parking station after the cleaning of entire solar panel array consisting of plurality of solar panels.
The embodiment of the present invention, the mobile solar panel cleaning robot consists of a metallic or non-metallic frame 2 on which a bottom drive 4, a top drive 3, two right limit switches or proximity sensors 65, two left limit switches or proximity sensors 66, a cleaning trolley 40, a motorized winch 31 with a wire rope 33, a control panel 50, supports for control panel 5, 6 and rechargeable batteries 51, 52 are mounted. The mobile solar panel cleaning robot travels laterally on the frame of top and bottom edges of the solar panel 1.
In the embodiment, the bottom drive of the mobile solar panel cleaning robot consists of tank type construction having two timer pulleys 14 each driven by a motor 15, a timer belt 12 and plurality of wheels 13 mounted on a metallic or non-metallic bar 4. One timer pulley has an encoder disc 16 having number of holes to detect the rotational counts, by a sensor (not shown), to obtain the position of wheel indicating travel of the mobile solar panel cleaning robot.

In the embodiment, the top drive of the mobile solar panel cleaning robot consists of tank type construction having two timer pulleys 21 each driven by a motor 15, a timer belt 24 and plurality of wheels 23 mounted on an metallic or non-metallic bar 3. One timer pulley has an encoder disc 25 having number of holes to detect the rotational counts, by a sensor (not shown), to obtain the position of wheel indicating travel of the mobile solar panel cleaning robot. Also, plurality of wheels 26 are mounted on metallic or non-metallic bar 3 perpendicular to the wheels 23.
In the embodiment, the cleaning trolley of the mobile solar panel cleaning robot consists of a frame 40 having two horizontal and two vertical metallic or non-metallic bars. The frame has four wheels 44 travelling on the metallic or non-metallic bar 2 and four wheels 43 that are mounted perpendicular to the wheels 44 that travel along the metallic or non-metallic bar 2.The cleaning trolley also has two ‘U’ shape frames 45 to contain the soft nylon brush 41, to clean the top surface of the solar panel, which is driven by a motor 42. The ‘U’ shape frame 45 is supported by two bolts such that the height of cleaning brushes can be adjusted to desired height so as not the damage the surface of the solar panel.
In the embodiment, a motorized winch is mounted on the top element of the frame 2. It consists of a bobbin 30 made of anti-rust material which is mounted by a frame 31 and driven by two motors 32. A wire rope 33 winds and unwinds on the bobbin while pulling

up or releasing down the cleaning trolley 40. The power and control cable folds and unfolds along with the cable drag chain 45.
In the embodiment, the parking station is provided for parking the robot when not in use for cleaning the solar panels. The parking station consists of a frame having two vertical metallic supports 61, two horizontal metallic supports 62 and four support legs 67. It has a solar panel mounted on two horizontal supports 63 and used for charging the on¬board rechargeable batteries 51 through the stationary insulated charging contacts 68. When the mobile robot is in parking position, the stationary insulated charging contacts 68 make connection with battery through the moving contacts mounted on limit switches 65.
In another embodiment of the mobile solar panel cleaning robot, the bottom drive consists of two motorized wheels 17, driven by the motor 18 mounted on the metal bar on the side of metal bar 2. An encoder disc 19 having number of holes to detect the rotational counts, by a sensor (not shown), to obtain the position of wheel indicating travel of the mobile solar panel cleaning robot.
In another embodiment, the top drive consists of two or more motorized wheels 28 each driven by a motor 27 and plurality of non-motorized wheels 29 mounted perpendicular to motorized wheels 28. An encoder disc 280 having number of holes to detect the

rotational counts, by a sensor (not shown), to obtain the position of wheel indicating travel of the mobile solar panel cleaning robot.
In another embodiment of the mobile solar panel cleaning robot, the cleaning trolley consists of a frame 40 having two horizontal and two vertical metal bars. The frame has four wheels 44 travelling on the metal bar 2 and four wheels 43 that are mounted perpendicular to the wheels 44 that travel along the metal bar 2.The cleaning trolley also has two ‘U’ shape frames 45 to contain the soft microfiber chenille cloth 47, to clean the top surface of the solar panel, which is driven by a motor 42. The ‘U’ shape frame 45 is supported by two bolts such that the height of soft microfiber chenille cloth can be adjusted to desired height so as not to damage the surface of the solar panel while cleaning.
In both the embodiments, the cleaning cycle consists of the mobile robot moving from its parked position to the desired cleaning position. In the cleaning position, the cleaning trolley is pulled up by wire rope winch, while the cleaning devices are rotating. The cleaning trolley after reaching the top position, is released by the motorized winch and descends down the metal bar at a controlled speed, while the cleaning devices are rotating. The frictional action of the cleaning devices on the solar panel top surface removes the accumulated dust particles on the surface. After this cleaning action, the mobile robot moves horizontally on two top edges and the bottom edge of the solar panel to the new cleaning position and the cleaning cycle repeats.

In the manual operation, the mobile robot is moved manually to the left or to the right directions, using a mobile phone, tablet PC or a computer connected wirelessly to the micro-controller or the Programmable Logic Controller (PLC) that is housed in the control panel 50. The similar manual operation is also done for the cleaning trolley to move it up or down and cleaning devices to rotate them clockwise or counter-clock wise.
In the automatic operation, the mobile robot moves automatically at a programmed time from its parked position to the desired cleaning position. In the cleaning position, the cleaning trolley is pulled up by wire rope winch, while the cleaning devices are rotating. The cleaning trolley after reaching the top position, is released by the motorized winch and descends down the metal bar at a controlled speed, while the cleaning devices are rotating. After the first cleaning cycle, the mobile robot moves horizontally on two top edges and the bottom edge of the solar panel to the new cleaning position and the automatic operation of new cleaning cycle begins. This operation is repeated till all the solar panels in an entire array are cleaned, the end position of which is detected by the two sensors 65 mounted at the top and bottom of the mobile robot. After the mobile robot reached its end position of the cleaning process, it automatically travels back to the parking position, where the end position is detected by the two sensors 66 mounted at the top and bottom of the mobile robot. After the mobile robot reaches its parked position in the parking station, it is automatically connected to a charging circuit to charge the on¬board batteries.

WE CLAIM
1. An automated programmable robotic solar panel cleaning system having a mobile
solar panel cleaning robot disposed on a metallic or non-metallic frame 2 comprising,
- a bottom drive (4), a top drive (3), two right limit switches or proximity sensors (65), two left limit switches or proximity sensors (66), a cleaning trolley (40), a motorized winch (31) with a wire rope (33), a control panel (50) with supports (5, 6), a rechargeable batteries (51, 52),
- a cleaning trolley
- a parking station
wherein, the cleaning robot travels laterally on the frame of top and bottom edges of the solar panel (1) to clean the array of panels without water or any chemicals.
2. The system as claimed in claim 1, wherein, the bottom drive (4) comprises, two timer pulleys (14) driven by motor (15), a timer belt (12), a plurality of wheels (13) mounted on metallic or non-metallic bar (4), wherein one timer pulley having an encoder disc (16) having no. of holes to detect the rotational counts through sensor indicating the position of the robot.
3. The system as claimed in claim 1, wherein, the top drive (3) comprises, two timer pulleys (21) driven by motor (15), a timer belt (24), plurality of wheels (23) mounted on metallic or non-metallic bar (3), wherein one timer pulley having an encoder disc

(25) having no. of hoes to detect the rotational counts through sensor indicating the position of the robot.
4. The system as claimed in claim 1, wherein the cleaning trolley comprises, a frame (40) having two horizontal and two vertical metallic or non-metallic bars, four wheels (44) travelling on the metallic or non-metallic bar (2), four wheels (43) mounted perpendicular to the wheels (44) travelling along the metallic or non-metallic bar 2, two U-shaped frames (45) holding soft nylon brush (41) to clean the top surface of the solar panel driven by the motor (42), wherein the height of the U-shaped frame can be adjusted through fixing bolts.
5. The system as claimed in claim 1, wherein the parking station disposed for parking, comprises a frame having two vertical metallic supports (61), two horizontal metallic supports (62), four support legs (67), wherein solar panel is mounted on two horizontal supports (63) adapted for charging on-board rechargeable batteries (51) through charging contacts (68) and connection by moving contacts of limit switches (65)
6. The system as claimed in claim 2, wherein, the bottom drive further comprising two motorized wheels (17) driven by the motor (18) mounted on the metal bar 2 along with an encoder disc (19) having no. of holes to detect the position and travel of the robot.

7. The system as claimed in claim 3, wherein, the top drive further comprising
motorized wheels (28) driven by motor (27) and plurality of non-motorized wheels
(29) mounted perpendicular to the motorized wheels (28) along with an encoder
(280) having no. of holes to detect the rotational counts and position of the solar
panel cleaning robot.
8. A method of automatic programmable robotic cleaning of solar panel having
motorized winch mounted on the top element of the frame (2) comprising a bobbin
(30) mounted by frame (31) driven by two motors (32), wherein the wire rope winds
and unwinds on the bobbin pulling up or releasing down the cleaning trolley 40,
folding and unfolding power and control cable along the cable drag chain 45.
9. The method as claimed in claim 8, wherein after the first cleaning cycle the mobile
robot moves horizontally on two top edges and the bottom edges of the solar panel
to the new cleaning position to begin the new cleaning cycle.