Vehicle mounted system for cleaning solar panels

Abstract

A system for cleaning active surfaces of solar panels arranged obliquely relative to the ground, the system comprising: an elongate cleaning head assembly comprising a plurality of cleaning brushes extending between two ends of an elongate cleaning head frame; one or more cleaning head actuators for effecting movement of the cleaning head frame and movement of the cleaning brushes the actuators being arranged to effect said movement of the cleaning head frame and the cleaning brushes; and contour and distance detection sensors to assess relative distance between the cleaning head assembly and the active cleaning surface of the solar panels during use; an articulated supporting arm assembly comprising a plurality of supporting arms interconnecting by movable joints, wherein: a proximal end of the supporting arm assembly being configured to be movably mounted to a vehicle for allowing the supporting arm assembly to swing relative to the vehicle; and a distal end of the arm assembly being movably attached to the cleaning head assembly for allowing the elongate head assembly to be inclined relative to the distal end of the supporting arm assembly at a plurality of inclination angles wherein the articulated arm assembly comprises one or more supporting arm actuators for effecting movement of the supporting arms; and a controller comprising a memory device with executable instructions to control movement of the cleaning head assembly and the supporting arm assembly by actuating one or more of the cleaning head actuators and one or more of the supporting arm actuators in response to measurements recorded by the contour and distance detection sensors when one or more predetermined criteria are satisfied.

Description

VEHICLE MOUNTED SYSTEM FOR CLEANING SOLAR PANELSTECHNICAL FIELD

[0001] The present invention relates to a vehicle mounted system and method for cleaning solar panels.BACKGROUND

[0002] Any references to methods, apparatus or documents of the prior art are not to be taken as constituting any evidence or admission that they formed, or form part of the common general knowledge.

[0003] Solar panels being used on solar farms are gaining popularity. Typically solar panels on such large farms are positioned on support structures in fields or large open areas.

[0004] Every solar farm normally comprises of hundreds if not thousands of solar panels that are arranged in a plurality of rows in an open area. There is normally some space left in between any two adjacent rows of solar panels to allow maintenance vehicles to be driven in between the rows of solar panels. Each solar panel substantially comprises an active surface for receiving the solar radiation in order to transform it into electrical energy. The active surface typically comprises an external layer, often made of a transparent material (for example glass) which protects and / or thermally insulates the operative components of the panel.

[0005] As the panels are positioned in the open, they are subject to atmospheric agents, pollution, covering by leaves or dead insects, etc. For this reason, the above- mentioned layer (which in the following we shall assume to be glass for reasons of simplicity in the illustration) over time gets soiled, which alters its transmitting characteristics, with a deterioration in the efficiency of the panel. It follows that the layer of glass of the modules constituting a given panel needs to be periodically cleaned.

[0006] At present this cleaning is manually performed, by specialised personnel provided with water, detergents and common tools used for cleaning domestic surfaces or glass, such as mops, cloths, brushes, buckets or other means for conveying or throwing water, etc. Not only is this manual operation laborious and expensive, both in terms of time and money, but it is affected by some other drawbacks.

[0007] It is known typically the solar panel modules are inclined by a given angle with respect to the ground they are resting on, and are orientated in a predetermined direction, which angle and direction are chosen according to the daily motion of the sun which varies according to geographic (i.e. latitude and longitude). As the panels are each formed by various coplanar modules, the personnel with the task of cleaning has to operate on an inclined surface.

[0008] Whilst automated cleaning equipment has been proposed in the past, the inclined active surface of the solar panels combined with the fragility of the glass surface of the solar panels, makes operation of any automated cleaning equipmentdifficult. Therefore, there is a need to provide improvements in cleaning systems that can assist with cleaning of such solar panels on large solar farms.SUMMARY OF INVENTION

[0009] In an aspect, the invention provides a system for cleaning active surfaces of solar panels arranged obliquely relative to the ground, the system comprising: an elongate cleaning head assembly comprising a plurality of cleaning brushes extending between two ends of an elongate cleaning head frame one or more cleaning head actuators for effecting movement of the cleaning head frame and movement of the cleaning brushes the actuators being arranged to effect said movement of the cleaning head frame and the cleaning brushes; and contour and distance detection sensors to assess relative distance between the cleaning head assembly and the active cleaning surface of the solar panels during use; an articulated supporting arm assembly comprising a plurality of supporting arms interconnecting by movable joints, wherein: a proximal end of the supporting arm assembly being configured to be movably mounted to a vehicle for allowing the supporting arm assembly to swing relative to the vehicle; and a distal end of the arm assembly being movably attached to the cleaning head assembly for allowing the elongate head assembly to be inclined relative to the distal end of the supporting arm assembly at a plurality of inclination angleswherein the articulated arm assembly comprises one or more supporting arm actuators for effecting movement of the supporting arms a controller comprising a memory device with executable instructions to control movement of the cleaning head assembly and the supporting arm assembly by actuating one or more of the cleaning head actuators and one or more of the supporting arm actuators in response to measurements recorded by the contour and distance detection sensors when one or more predetermined criteria are satisfied.

[0010] In an embodiment, the system further comprises: one or more motion or inclination sensors for sensing motion and / or orientation of the longitudinal axis of the elongate cleaning head assembly or vehicle, and wherein the controller is arranged to control movement of the cleaning head assembly and the supporting arm assembly by actuating one or more of the cleaning head actuators and one or more of the supporting arm actuators in response to measurements recorded by the motion or inclination sensors when: one or more of the predetermined criteria are satisfied or additional criteria are satisfied.

[0011] In an embodiment, the system further comprises load cell sensors being disposed on the cleaning head frame, the load cell sensors being arranged to measure a plurality of force and / or moment components and wherein the controller is arranged to control movement of the cleaning head assembly and the supporting arm assembly by actuating one or more of the cleaning head actuators and one or more of the supporting arm actuators in response to measurements recorded by the load cell sensors when one or more additional predetermined criteria are satisfied.

[0012] In an embodiment, the cleaning head assembly comprises a connecting subassembly located along a generally central portion of the elongate cleaning head frame for connecting said cleaning head assembly to the distal end of the supporting arm assembly , the connecting assembly being linked with a head jack located at the distal end of the supporting arm assembly such that actuation of the head jack effects movement of the connecting sub-assembly and the cleaning head assembly fixedly mounted thereon.

[0013] In an embodiment, the load cell sensors are located at or adjacent the connecting sub-assembly.

[0014] In an embodiment, the inclination sensors and / or motion sensors are located at or adjacent the connecting sub-assembly.

[0015] In an alternative embodiment, the inclination sensors or motion sensors are located in the vehicle and sense inclination or motion of the vehicle.

[0016] In an embodiment, each of said supporting arm actuators is located adjacent a corresponding moving joint to effect rotary movement of the supporting arms interconnected by said corresponding moving joint.

[0017] In an embodiment, the system further comprises rotary sensors located at the moving joint for sensing rotary position of the interconnected supporting arms.

[0018] In an embodiment, the supporting arm actuators comprise hydraulic rams, wherein each hydraulic ram is configured for effecting relative rotation between adjacently located interconnected supporting arms during use.

[0019] In an embodiment, at least a first plurality of contour and distance detection sensors are located in the cleaning head assembly.

[0020] In an embodiment, the first plurality of contour and distance detection sensors comprises ultrasonic sensors. In an embodiment, at least a second plurality of contour and distance detection sensors comprise LIDAR sensors.

[0021] In an embodiment, the plurality of supporting arms interconnecting by the movable joints further comprise respective joint encoders for sensing movement of the supporting arms in three dimensional space.BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows:Figure 1 is a frontal perspective view of a cleaning system 1000 mounted to a tractor T in accordance with a preferred embodiment.Figure 2 is a bottom perspective view of the cleaning system 1000.Figure 3 is a top perspective view of the cleaning system 1000.Figure 4A is a block diagram of the controller 300 controlling the operation of the cleaning system 1000 in accordance with a first embodiment.Figure 4B is a block diagram of the controller 300 controlling the operation of the cleaning system 1000' in accordance with a second embodiment.Figure 4C is a block diagram of the controller 300 controlling the operation of the cleaning system 1000" in accordance with a second embodiment.Figure 4D is a block diagram of the controller 300 controlling the operation of the cleaning system 1000"' in accordance with a second embodiment.DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0023] Figures 1 illustrates a cleaning system 1000 which is mounted to a prime mover, namely a tractor denoted by T. The invention as described herein is not limited by the type of vehicle that is used in conjunction with the cleaning system 1000. As will be evident, from the foregoing sections, the provision of the vehicle mounted cleaning system 1000 provides at least a semi-autonomous and, in some embodiments, a fully autonomous cleaning system which can easily carry out solar panel cleaning while the driver can focus on driving the vehicle T in between rows of solar panels. It is also to be understood that the cleaning system 1000 may also be used in conjunction with a fully autonomous and self-driving vehicle without departing from the spirit and scope of the invention.

[0024] The cleaning system 1000 comprises an articulated supporting arm assembly 100 with a proximal end 101 and a distal end 103. The proximal end 101 is movablymounted to the tractor T to allow the supporting arm assembly to swivel laterally (towards the left-hand side or the right-hand side). The movable mounting arrangement allows the proximal end of the supporting arm assembly to swivel towards the left or the right side of the vehicle as the vehicle is moving forwards along a straight line. The swivel mechanism may be provided by a plurality of possible swivel arrangements.

[0025] Specifically, the proximal end 101 of the supporting arm assembly comprises proximal arm member 110 that is mounted via a connecting assembly 104 to an attachment bracket 106 that is fixedly attached to the tractor T. The connecting assembly 104 (and the proximal arm member 110 mounted thereon) is arranged to undergo swivel relative to the vehicle attachment bracket 106 such that the supporting arm assembly 100 can be swivelled laterally towards the left or towards the right as the tractor T is being driven in a straight line in between rows of solar panels.

[0026] The supporting arm assembly 100 also comprises a distal arm member 120 that is attached to a cleaning head assembly 200. The cleaning head assembly has been described in further detail in the subsequent sections.

[0027] The supporting arm assembly 100 comprises a plurality of arm members (denoted generally by 115) that are interconnected at their respective ends by articulating joints that allow adjacent supporting arms to articulate relative to each other. Articulating movement for each of the intermediate supporting arms 115 and the proximal and distal arms 110 and 120 may be achieved by providing hydraulic rams or actuators 117 as shown in the accompanying figures. Rotary encoders 119 may also be provided at each articulating joint to sense the relative rotation between anytwo interconnected supporting arms of the supporting arm assembly 100. The role of the rotary encoders 119 will be discussed in further detail when the operation of the system 100 is explained in the foregoing sections. In the preferred embodiment, each articulating joint for the supporting arm assembly 100 is shown to have one degree of freedom movement. However, more than one degree of freedom movement may be provided for each of the articulating joints for the interconnected supporting arms.

[0028] The supporting arm assembly 100, at its distal end is connected to a generally elongate cleaning head assembly 200 via a connecting sub-assembly 130 such that the elongate cleaning head assembly 200 is movably connected to cleaning head assembly 200 to allow the cleaning head assembly to be oriented transversely relative to the distal arm 120. The connecting sub-assembly 130 provides an articulating moving mechanism whilst being connected to the cleaning head frame 210 along a generally central region of the cleaning head frame 210.

[0029] The elongate cleaning head assembly 200 comprises a plurality of cleaning brushes 220 extending between two ends of an elongate cleaning head frame 210. The cleaning brushes 220 may be actuated by one or more actuators in the cleaning head assembly 200. The actuators have not been shown in the drawings. However, any conventional cleaning brush actuation mechanism may be used in conjunction with the cleaning head assembly 200. For example, the brushes 220 may be mounted along a shaft extending between the ends of the elongate cleaning head frame 210 actuated by one or more actuators that result in rotation of the shaft and the associated cleaning brushes 220. It is important to note that cleaning brushes 220 being used with the cleaning head assembly 200 must be suitable for cleaning smooth glass surfaces without breaking or damaging the outer glass surface of the solar panels.

[0030] The cleaning head assembly 200 also comprises optional load cell sensors 140 that are disposed within the connecting subassembly 130 to measure force or moment components acting on the cleaning head assembly 200. Specifically, when the cleaning brushes 220 come into contact with the solar panels, the cleaning head frame 210 experiences a reaction force due to the engagement of the cleaning brushes 220 and the surface of the solar panel being cleaned. The problem with some other prior art cleaning systems is that sudden impact between the cleaning head assembly 200 and the glass surface of the solar panels can damage or break the solar panel outer layer made out of fragile glass. In the foregoing sections, the functionality of sensing any forces or moments acting on the cleaning head frame 210 during engagement of the brushes 220 with the active surface during operation will be discussed. It may be understood that whilst the preferred embodiment illustrates the use of load cell sensors 140, further embodiments may be developed without the provision of the load cell sensors 140.

[0031] The cleaning head assembly 200 also comprises one or more inclinometers or motion sensors 150 being located within connecting subassembly 130 for sensing either motion and / or an orientation of the longitudinal axis of the elongate cleaning head assembly 200. Solar panels, especially the solar panels of the type that are erected on solar farms have an obliquely oriented active surface. The angle of orientation for such panels can vary and therefore sensing and controlling motion and / or inclination of the elongate cleaning head assembly 200 is important to ensure that the cleaning head assembly 200 can be used for sweeping and cleaning the active surface of the solar panels in an effective manner without damaging the active surface of the solar panel. In alternative embodiments, the motion sensors 150 may also belocated within the vehicle or tractor T. In such an embodiment, the IMU motion sensors to detect motion of the tractor itself which occurs as the vehicle moves over uneven terrain. Such motion would in turn otherwise result in unwanted movement of the cleaning brush. By detecting this movement of the vehicle, compensating movement commands can be sent to the articulated arm assembly 100, such that the distance of the brush relative to the solar panels remains constant despite motion of the vehicle.

[0032] The cleaning head assembly 200 further comprises contour and distance detection sensors in the form of ultrasonic sensors 160 to assess relative distance between the cleaning head assembly 200 and the active cleaning surface of the solar panels during use. The ultrasonic sensors 160 are advantageously located lateral side regions of the elongate frame 210. The elongate cleaning head frame 210 comprises lateral frame members 215 upon which the ultrasonic sensors 160 are mounted. The ultrasonic sensors 160 may be located along the lateral and peripheral parts of the frame in order to send out ultrasonic waves towards the active surface of the solar panels to sense the contours and distance from the active surface. It is important that the cleaning brushes 220 do not obstruct the ultrasonic sensors during use. Through rigorous trials and experimentation, it has been found that the combination of the distance and contour sensors (ultrasonic sensors 160) with the motion or inclination sensors 150 provides autonomous control for the solar panel cleaning system 1000. In some embodiments, contour and distance detection may also be carried out by LIDAR (Light Detection & Ranging) sensors 165. The LIDAR sensors 165 may be used as an alternative to the ultrasonic sensors 160. In other embodiments, the LIDAR sensors 165 may also be used in addition to the ultrasonic sensors 160.

[0033] Referring to Figure 4A, a block diagram is shown for depicting the operation of the system 1000 in accordance with a first embodiment. A controller in the form of a PLC (programmable logic controller) 300 is provided to control operation and movement of the supporting arm assembly 100 and the cleaning head assembly 200. Specifically, the PLC 300 monitors operating parameters sensed by the load cell sensors 140, inclinometer sensors 150 and the ultrasonic sensors 160. A CANbus protocol is used for communications between the PLC 300 and the load cell sensors 140, inclinometer sensors 150 and the ultrasonic sensors 160. It is to be understood that other network protocols may also be utilized without departing from the spirit and scope of the invention. Any other alternative communication pathway may be utilized. The PLC 300 may include a memory device with executable instructions to send operating commands for controlling the operation of the supporting arm assembly 100 and the cleaning head 200 when certain preset criteria in relation to sensor data received from the load cell sensors 140 and / or inclinometer sensors 150 and / or the ultrasonic sensors 160 or LIDAR sensors 165 are met. Specifically, when one or more preset criteria are satisfied, the hydraulic actuators may be actuated by operation of hydraulic valves to position the supporting arm assembly 100 and the cleaning head assembly 200 into one or more corresponding operating modes as will be described in the following sections.

[0034] Referring to Figure 4A, the PLC 300 may be configured to be operably connected to the supporting arm assembly 100 to control movement of the supporting arm assembly 100. The vehicle T may also be operatively coupled to the PLC 300 via analogue inputs and CAN BUS protocols. A joystick 410 may be provided for an operator driver to receive manual input from the operator and execute variousoperation movements for the supporting arm assembly 100 through various CANBUS protocols via the PLC 300. The vehicle’s analogue controls such as the steering wheel motor 420, the foot pedal sensor 430 and steering angle sensor 440

[0035] Figures 4B, 4C and 4D illustrate box diagrams for alternative embodiments of systems 1000', 1000" and 1000"'. Like reference numerals denote like features and function in a manner as previously described.

[0036] Figure 4B depicts a system 1000' in which the load cell sensors 140 and the LIDAR sensor 165 are not required to carry out cleaning of the solar panels during use of the system 1000' in at least some operating configurations. In such a system, the load cell sensor 140 and the LIDAR sensor 165 are optional.

[0037] Figure 4C depicts a system 1000" in which the inclinometer sensors 150 (or IMU units) and the LIDAR sensors 165 are not required to carry out cleaning of the solar panels during use of the system 1000' in at least some operating configurations. In such a system, the inclinometer sensor 150 and the LIDAR sensor 165 is optional.

[0038] Figure 4D depicts a system 1000'" in which the inclinometer sensors 150 (or IMU units) and the load cell sensors 140 are not required to carry out cleaning of the solar panels during use of the system 1000' in at least some operating configurations. In such a system, the inclinometer sensor 150 and the load cell sensors 140 are optional.

[0039] In the presently described embodiment, the system 1000 may be operated in a “MANUAL” mode, an “AUTO CLEAN” mode and a “TELEOP” mode. Momentary push buttons may be provided on a control panel in communication with the PLC 300 to toggle between the three modes.

[0040] In the “MANUAL” mode, the operation of the supporting arm assembly 100 and the associated cleaning head 200 is carried out manually using the joystick. This mode is particularly useful when the tractor T is being driven into an initial position at the start of a row of solar panels. A first indicator may also be provided to indicate that the system 1000 is under Manual control of the operator. Inputs from the joystick or the home button are considered "operator control inputs". Upon receiving any operator control inputs, the system will change to Manual mode if not already in Manual mode. Joystick controls will move the supporting arm assembly 100 in the same way that they are currently configured on the machine. Press and holding the home button will execute a joint trajectory to bring the arm assembly 100 to a pre-defined home position. Releasing the button will stop the movement. In the case of joystick inputs during execution of a home trajectory, the joystick inputs will take precedence. An emergency stop (E-Stop) function is also provided to immediately stop any movement of the supporting arm assembly 100. The E-stop is considered a "last resort". In normal error handling, the operator should press the manual mode button or provide an operator control input to transition the system back to Manual mode.

[0041] An enabling function may be used or engaged to transition the supporting arm assembly 100 out of the MANUAL mode.

[0042] While in TELEOP mode, the PLC 300 shall respond to actuation commands from an on-board computing device or remote server. In the TELEOP mode, acleaning cycle utilizing the cleaning head assembly 200 will not be undertaken. Instead in the TELEOP mode commands may be received from a remote server or an board computing device including but not limited to a handheld mobile computing device. This mode is primarily a "testing" mode. Note the same operator control input overrides discussed above still apply in this mode.EXEMPLARY OPERATION OF SYSTEM 100

[0043] In an exemplary and non-limiting operation, the operator takes control of the tractor or any other prime mover vehicle and the system 1000 is typically operated initially in the MANUAL mode. The Operator is able to manoeuvre the arm assembly 100 as necessary using the joystick and drive the vehicle T to start cleaning a row of panels. While approaching each row of solar panels, the operator monitors detection display provided for viewing by the operator. In the presently described embodiment, the operator may deploy one or more hydraulic valves to effect movement of the supporting arm assembly 100 and the cleaning head assembly 20 to substantially align the cleaning head assembly in close proximity to the active surface of the solar panels. The detection display may provide critical sensor data such distance between the cleaning head assembly 200 and the active surface received from the ultrasonic sensors 160. The detection display may also provide important detection data from the inclinometer 150 or the load cells 140. The operator may use the data provided on the detection display to assist with aligning the supporting arm assembly 100 and the cleaning head assembly 200 into a “ready to clean” position. Once the arm assembly 100 and the cleaning head assembly 200 is in the substantially aligned “ready to clean” mode, the operator may switch the system 1000 to AUTO CLEAN mode. In this mode, the operator is only expected to drive in a substantially straight line alongside a row ofsolar panels whilst relinquishing control of the movements for the supporting arm assembly 100 and / or the cleaning head assembly 200. The operator can view detection data on the detection display which displays nominal detections and the cleaning brushes 220 are performing correctly without applying undue force.

[0044] Various failure scenarios may be pre-programmed to provide alerts to the operator and in some instances stop operation in the AUTO CLEAN mode. During cleaning, if the operator notices an abnormal detection, the operator will switch the system to Manual, which will disable autonomy and revert to joystick control (note this means that with no operator input the system will hold the brush in its current position) where the operator can manoeuvre it as necessary, in some instances, an alarm or alert may be triggered even in the MANUAL mode if detection parameters for a failure event are satisfied. For example, if any of the detectors detect the possibility of a collision between the arm assembly 100 and / or the cleaning head assembly 200 then an audible alarm or visual alarm may be triggered.

[0045] Whilst driving down row, the following autonomous sub-states of the Auto Clean mode may occur:• When out of range of a panel in the row, system 1000 will display an OUT OF RANGE configuration.• When within "range" of a panel, the system 100 will transition to TARGETING, and the brush will move to meet the panel, as the tractor drives towards it• When over a panel, but not yet in contact, the system 1000 will transition to ENGAGING, where the brushes 220 will move to engage with the panel• Once the brushes 220 have engaged the panel, the system 1000 will transition to TRACKING, where the brushes 220 will maintain a constant force applied to the active surface of the panels.• When the edge of a panel is detected, the system will transition to DISENGAGING, where the brushes 220 will disengage from the panel and maintain a safe distance from the panel.• The system will then transition back to OUT OF RANGE or TARGETING, depending on if another panel has been detected, and repeat this sub list.• At the end of the row, the system will detect the edge of the last panel, and disengage (ending in the OUT OF RANGE state)

[0046] After the system has disengaged, the operator switches the system to Manual and drives the tractor to the start of the next row of panels, manoeuvring the arm as necessary.

[0047] The system 1000 may also non-exasutively include other detectors that assist with monitoring the serviceability of the system 1000 by monitoring the hydraulic system pressures (associated with the hydraulic actuators of the supporting arm assembly 100), the hydraulic pump rpm, arm pose (IMU vs rotary encoder positions).

[0048] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. The term “comprises” and its variations, such as “comprising” and “comprised of” is used throughout in an inclusive sense and not to the exclusion of any additional features.

[0049] It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect.

[0050] The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted by those skilled in the art.

Claims

CLAIMS1 . A system for cleaning active surfaces of solar panels arranged obliquely relative to the ground, the system comprising: an elongate cleaning head assembly comprising a plurality of cleaning brushes extending between two ends of an elongate cleaning head frame one or more cleaning head actuators for effecting movement of the cleaning head frame and movement of the cleaning brushes, the actuators being arranged to effect said movement of the cleaning head frame and the cleaning brushes; and contour and distance detection sensors to assess relative distance between the cleaning head assembly and the active cleaning surface of the solar panels during use; an articulated supporting arm assembly comprising a plurality of supporting arms interconnecting by movable joints, wherein: a proximal end of the supporting arm assembly being configured to be movably mounted to a vehicle for allowing the supporting arm assembly to swing relative to the vehicle; and a distal end of the arm assembly being movably attached to the cleaning head assembly for allowing the elongate head assembly to be inclined relative to the distal end of the supporting arm assembly at a plurality of inclination angles wherein the articulated arm assembly comprises one or more supporting arm actuators for effecting movement of the supporting armsa controller comprising a memory device with executable instructions to control movement of the cleaning head assembly and the supporting arm assembly by actuating one or more of the cleaning head actuators and one or more of the supporting arm actuators in response to measurements recorded by the contour and distance detection sensors when one or more predetermined criteria are satisfied.

2. A system in accordance with claim 1 further comprising: one or more motion or inclination sensors for sensing motion and / or orientation of the longitudinal axis of the elongate cleaning head assembly or vehicle, and wherein the controller is arranged to control movement of the cleaning head assembly and the supporting arm assembly by actuating one or more of the cleaning head actuators and one or more of the supporting arm actuators in response to measurements recorded by the motion or inclination sensors when: one or more of the predetermined criteria are satisfied or additional criteria are satisfied.

3. A system in accordance with claim 1 or claim 2 further comprising load cell sensors being disposed on the cleaning head frame, the load cell sensors being arranged to measure a plurality of force and / or moment components and wherein the controller is arranged to control movement of the cleaning head assembly and the supporting arm assembly by actuating one or more of the cleaning head actuators and one or more of the supporting arm actuators in response to measurements recorded by the load cell sensors when one or more additional predetermined criteria are satisfied .

4. A system in accordance with any one of the preceding claims wherein the cleaning head assembly comprises a connecting sub-assembly located along a generally central portion of the elongate cleaning head frame for connecting said cleaning head assembly to the distal end of the supporting arm assembly , the connecting assembly being linked with a head jack located at the distal end of the supporting arm assembly such that actuation of the head jack effects movement of the connecting sub-assembly and the cleaning head assembly fixedly mounted thereon.

5. A system in accordance with claim 3 wherein the load cell sensors are located at or adjacent the connecting sub-assembly.

6. A system in accordance with any one of the preceding claims 2 to 5 wherein the inclination sensors or motion sensors are located at or adjacent the connecting sub-assembly.

7. A system in accordance with any one of claims 1 to 5 wherein the inclination sensors or motion sensors are located in the vehicle.

8. A system in accordance with any one of the preceding claims wherein each of said supporting arm actuators is located adjacent a corresponding moving joint to effect rotary movement of the supporting arms interconnected by said corresponding moving joint.

9. A system in accordance with claim 6 further comprising rotary sensors located at the moving joint for sensing rotary position of the interconnected supporting arms.

10. A system in accordance with any one of the preceding claims wherein the supporting arm actuators comprise hydraulic rams, wherein each hydraulic ram is configured for effecting relative rotation between adjacently located interconnected supporting arms during use.

11. A system in accordance with any one of the preceding claims wherein at least a first plurality of contour and distance detection sensors are located in the cleaning head assembly.

12. A system in accordance with claim 11 wherein the first plurality of contour and distance detection sensors comprises ultrasonic sensors.

13. A system in accordance with any one of the preceding claims wherein at least a second plurality of contour and distance detection sensors comprise LIDAR sensors.

14. A system in accordance with any one of the preceding claims wherein the plurality of supporting arms interconnecting by the movable joints further comprise respective joint encoders for sensing movement of the supporting arms in three dimensional space.

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