The present disclosure relates to the field of automatic cleaning, and in particular to automatic cleaning of elongated objects in order to eliminate the variation and uncertainty of the results of manual cleaning. In particular, the disclosure relates to a cleaning apparatus, a system for cleaning at least one industrial robot including the cleaning apparatus, and a method for cleaning. Background

Equipment used in the handling of open food products i.e. fish, meat, poultry and dairy is subject to strict hygiene requirements and must be washed down daily using hot high pressure water and chemical agents. At present cleaning is often performed manually by a cleaning team equipped with high-pressure spray lances that works through the night to ensure the equipment is clean in time for the morning shift. The effectiveness of this wash down depends to a large extent on the skill of the cleaning workers, and failure to follow the correct procedure can have serious implications for the food facility. Overenthusiastic use of the pressure spray near to sensitive areas such as bearings can damage seals, which results in accelerated corrosion, lubrication leakage and premature failure of equipment, while insufficient cleaning can allow bacteria to develop - a problem that first manifests itself weeks later when customers become ill from

contaminated products. Hard spraying also results in a lot of aerosol particles in the air which may contaminate other areas. For these reasons, food-factory owners are anxious to find methods of standardizing the wash down procedure to eliminate the variation and uncertainty of the results of manual washing.

Furthermore, since operators are working long hours during night time in a cold environment and are exposed to chemical and biological hazards, the cost for the workers is high which make the wash down procedure expensive.

The variability of the cleaning result from manual wash down exists for food- handling equipment in general, but will arguably be exacerbated for robots. This because an anticipated increased use of robots will increase the degree to which equipment is enclosed within safety fences. If the enclosures are not designed to provide sufficient access for cleaning then operators will either be tempted to spray at a too close range, risking damage to seals, or may miss parts of the robot altogether, risking development of bacteria colonies.

Also in other areas where washing is performed, the manual or semi-manual wash down depends on the skill of the cleaning workers. There may also be complicating factors where the object to be cleaned is hard to reach or has such a shape that it makes the washing difficult. There is thus a need for a more standardized method for washing an object, and especially for an elongated object that has to be cleaned all around its body, such that the cleaning result can be made more independent from the skill of the cleaning workers. From DE4129778A1 an automatic cleaning apparatus for painting robots is known. An encapsulated spray tank, open at the top, is located in the working area reached by a working arm of the robot. The tank includes inward -directed high pressure nozzles for paint solvent and compressed air nozzles for drying located on the tank circumference. The working arm is moved into the tank, and during the movement of the arm, the arm is exposed to washing and drying.

From KR200701 14959A an auto cleaning apparatus and method for cleaning a robot arm is known. A wafer absorbing part of a robot arm is inserted through an inlet/outlet of a box, and is exposed to a cleaning solvent via spray nozzles positioned inside the box adjacent to the wafer absorbing part. The apparatus is rather complicated and specially adapted to the wafer absorbing part of the robot arm.

Summary

In view of the above, there is a need for an apparatus that can be used to automatically clean different kinds of elongated objects, e.g. different kinds of robot arms. It is thus an objective of the disclosure to alleviate at least some of the drawbacks with the prior art. It is a further objective of the disclosure to provide an apparatus that may be adapted to different kinds of elongated objects, e.g. robot arms, in order to clean them efficiently. It is a still further object of the disclosure to provide an apparatus that can provide an automatic and repeatable cleaning in a cost efficient way. It is another further objective to provide an apparatus that is able to cooperate with the object it is cleaning in order to make the cleaning more efficient. These objects and others are at least partly achieved by the apparatus, system and method according to the independent claims, and by the

embodiments according to the dependent claims.

According to a first aspect, the disclosure relates to a cleaning apparatus for cleaning of an elongated object. The cleaning apparatus includes an annular cleaning part and an upper part. The annular cleaning part includes a plurality of inwardly directed nozzles arranged to be connected to a fluid supply for passing of fluid to the nozzles. The annular cleaning part is further arranged suspended from the upper part by means of retractable suspensions arranged to be actuated by at least one actuator arranged to the upper part. The cleaning apparatus further includes a cleaning control unit arranged to automatically control the at least one actuator according to control instructions in order to move the annular cleaning part over the elongated object by actuating the retractable suspensions.

With the cleaning apparatus an automated wash down of an elongated object such as a food-handling robot can be obtained. The cleaning apparatus enables a repeatable and standardized cleaning procedure, which will improve hygiene through reduced risk of bacteria colony development. The robot lifetime can be improved as the automated cleaning procedure means less wear to the robot compared to manual wash down. The cleaning can be made faster which reduces the downtime for cleaning. Further, as less or none manual work has to be done, the cost for labour is decreased. The floor space utilization can also be increased as robot enclosures can be made smaller. According to one embodiment, each of the retractable suspensions is arranged to be actuated by a separate actuator arranged to the upper part. According to one embodiment, the cleaning control unit is arranged to control the actuators to actuate the retractable suspensions to different lengths such that the annular cleaning part tilts.

According to one embodiment, each retractable suspension includes a cord, and each actuator includes a motor driven winch, wherein each cord is arranged to a respective winch.

According to one embodiment, the cleaning apparatus includes a fluid tight hose for passing of fluid from the fluid supply to the plurality of inwardly directed nozzles, wherein the hose is arranged along the retractable suspensions in a helix formation such that the hose follows any movement of the annular cleaning part.

According to one embodiment, the cleaning apparatus includes a valve unit arranged to control a fluid flow to at least one of the plurality of nozzles, and wherein the cleaning control unit is arranged to control the fluid flow to the at least one of the plurality of nozzle by controlling the valve unit.

According to one embodiment, the annular cleaning part is arranged with at least one inwardly directed ultra violet light source.

According to one embodiment, the upper part is arranged to be suspended from an attachment point and the annular cleaning part is arranged below the upper part and is arranged to be moved over the elongated object in a vertical direction. According to one embodiment, the upper part is hollow and the cleaning apparatus is arrange to be set into a retracted state where the annular cleaning part is accommodated into the hollowness by retraction of the retractable suspensions.

According to one embodiment, the upper part has an axial through hole with a diameter large enough to surround an industrial robot.

According to one embodiment, the annular part is arranged with a plurality of image capturing devices. According to a second aspect, the disclosure relates to a system for cleaning industrial robots, the system including at least one cleaning apparatus, wherein a robot controller of an industrial robot to be cleaned is configured to control motion of the industrial robot to be cleaned, and the cleaning control unit is configured to control the cleaning apparatus, in synchronization with each other.

According to one embodiment, the robot controller of the industrial robot to be cleaned is arranged to send control instructions to the cleaning control unit in order to control the cleaning apparatus. According to one embodiment, the system includes a mobile platform arranged to transport the at least one cleaning apparatus, wherein the at least one cleaning apparatus is arranged suspended from a stand of the mobile platform.

According to a third aspect, the disclosure relates to a method for cleaning an industrial robot with a robot arm. The method includes:

- positioning the cleaning apparatus according to any of the embodiments herein vertically above the robot arm of the robot;

- controlling the robot arm to a vertical pose;

- moving the annular cleaning part over the robot arm while passing fluid through the nozzles;

- controlling motion of the robot arm and motion of the annular cleaning part in synchronization in order to clean the robot arm. Brief description of the drawings

Fig. 1 illustrates an example of a robotized meat-slicing cell.

Fig. 2 illustrates an example of a deployed cleaning apparatus.

Fig. 3 illustrates an example of the cleaning apparatus in Fig. 2 where the interior of the upper part is made visible from the outside.

Fig. 4A illustrates the cleaning apparatus of Fig. 2 in a deployed state.

Fig. 4B illustrates the cleaning apparatus of Fig. 2 in a stowed state.

Fig. 4C illustrates an annular cleaning part of the cleaning apparatus of Fig. 2. Fig. 5 illustrates an example of a mobile platform arranged with a cleaning apparatus in a stowed state.

Fig. 6 illustrates an annular cleaning part according to an alternative embodiment of the cleaning apparatus.

Fig. 7 illustrates a controller of a robot and a cleaning control unit according to one embodiment.

Fig. 8 illustrates a flowchart of a method for cleaning an industrial robot according to one embodiment.

Detailed description

In the following different embodiments of a cleaning apparatus developed for cleaning elongated objects, especially robot arms, will be explained. The different embodiments of the cleaning apparatus will be illustrated in isolation or deployed in a system for cleaning at least one industrial robot. In the following description the term cleaning is intended to include a whole process of cleaning an elongated object, including any of washing, drying, disinfection etc.

In Fig. 1 an example of a robotized open food handling facility is illustrated. The facility here includes a system 13 for cleaning a first robot 14A with a robot arm 9A and a second robot 14B with a robot arm 9B that are used in the facility. The first robot 14A is arranged to pick up large pieces of meat from an input buffer and places the meat on a machine conveyor 18A of a slicing machine 20. The machine conveyor 18A transports the meat into the slicing machine 20 at one end. The slicing machine 20 slices the meat, and meat slices emerge at the other end of the machine 20. The meat slices are picked by the second robot 14B, which loads them into a tray and places them on the exit conveyor 18B. The exit conveyor 18B transports the trays to another machine (not shown) where they are sealed with a plastic cover. The first robot 14A, the second robot 14B, the slicing machine 20, the machine conveyor 18A and the exit conveyor 18B are all part of a cell. The cell is fenced by an enclosure 17 e.g. made of transparent plastic or glass, in order to prevent anybody from coming too close to the cell. Power to the cell is delivered from a cable of the facility via a pole 19. Cleaning apparatuses 1 included in the system 13 for cleaning are arranged suspended from support structures 21 arranged to the enclosure 17.

The first robot 14A and the second robot 14B are industrial robots. An industrial robot is here defined to be a robot that can be automatically controlled, that is reprogrammable, that can adopt to a multitude of tasks and has three or more axes. However, the first robot 14A and the second robot 14B here are serial six axis robots. The first robot 14A is arranged to be controlled by a robot controller 15A, and the second robot 14A is arranged to be controlled by a robot controller 15B. Each robot controller 15A, 15B includes a memory 29 (Fig. 7) and a processor 30 (Fig. 7). The memory 29 may be made up of one or several memory units. The processor 30 may be made up of one or several CPUs (Central Processing Units). The first robot 14A and the second robot 14B each has a sealed construction to provide a water proof surface that can be washed and at the same time protects the parts of the robot 14A, 14B, and also protects the environment from residuals from the robot 14A, 14B, e.g. lubrication oil. All cables of a robot 14A, 14B reside inside the sealed construction. The sealed construction is typically made of stainless steel. The sealed construction may have a tube shape and be made of a plurality of interconnected tubes. In Fig. 2 one of the cleaning apparatuses 1 of Fig. 1 is illustrated in more detail and in a deployed state. The cleaning apparatus 1 is arranged to one of the support structures 21 . The support structure 21 here has an L-shape with a horizontal part arranged to the cell and a vertical part arranged to the horizontal part, the horizontal part reaching into the cell over the first robot 14A. The cleaning apparatus 1 is here arranged suspended from the longitudinal part above the robot arm 9A of the first robot 14A in a detracted or deployed state. The cleaning apparatus 1 includes an annular cleaning part 2 and an upper part 3. When the cleaning apparatus 1 is in a retracted state as in Fig. 1 , the annular cleaning part 2 is housed inside the upper part 3. As can be seen from the enlarged view of the annular cleaning part 2 in the upper left corner of Fig. 2, the annular cleaning part 2 includes a plurality of inwardly directed nozzles 5. The nozzles 5 are connected to a fluid supply 6 for passing of fluid to the nozzles 5 via a fluid tight hose 10. According to one embodiment, the fluid supply 6 includes at least one compressing pump arranged to supply a flow of compressed water and/or compressed air. The fluid supply 6 may thus include one water

compressing pump and/or one air compressing pump.

The annular cleaning part 2 is arranged suspended from the upper part 3 by means of retractable suspensions 4. The first robot 1 is controlled to take an upright pose such that the annular cleaning part 2 can be brought over the robot arm 9A of the first robot 1 inside the annular cleaning part 2. The end effector of the first robot 14A, here a robot gripper 34, is the uppermost part of the robot 14A in this pose. By moving the annular cleaning part 2 over the robot arm 9A while passing fluid through the nozzles 5, the robot arm 9A is being washed. A nozzle 5 may be a high pressure jet nozzle. In Fig. 3 the cleaning apparatus 1 is illustrated in isolation, and the upper part 3 has been made transparent such that the parts inside the upper part 3 are visible from the outside. The cleaning apparatus 1 includes an attachment part 25 on the upper part 3 from which it can be suspended. The cleaning apparatus 1 here has three retractable suspensions 4. Alternatively, the cleaning apparatus 1 could have more than three retractable suspensions 4, e.g. 4 to 10 retractable suspensions 4. Each retractable suspensions 4 includes a cord that may be wound. Each retractable suspension 4 is arranged to be actuated by at least one actuator 7. The at least one actuator 7 is arranged inside the upper part 3. In Fig. 3 each of the retractable suspensions 4 is arranged to be actuated by a separate actuator 7 arranged to the upper part 3. Each actuator 7 includes a motor driven winch, and each retractable suspension 4 is at one end arranged to a respective winch. When an actuator 7 is being driven in a first direction, the retractable suspension 4 passed around the winch is retracted. When the actuator 7 is driven in a second direction, the retractable suspension 4 is being let out. Each retractable suspension 4 is further attached to the annular cleaning part 2 at its other end. Alternatively, all retractable suspensions 4 may be actuated by a common actuator 7. A direction device (not shown) may then be used to direct the retractable suspensions 4 to the common actuator 7, e.g. a motor driven winch. The cleaning apparatus 1 further includes a cleaning control unit 8 arranged to automatically control the at least one actuator 7 according to control instructions in order to move the annular cleaning part 2 over the robot arm 9A, by actuating the retractable suspensions 4. Meanwhile, fluid can be passed through the plurality of inwardly directed nozzles 5 in order to clean the robot arm 9A. The cleaning control unit 8 incudes a memory 31 (Fig. 7) and a processor 32 (Fig. 7). The memory 31 may be made up of one or several memory units. The processor 32 may be made up of one or several CPUs.

If each retractable suspension 4 is arranged to a separate actuator 7, the annular cleaning part 2 can be made to tilt. The cleaning control unit 8 is then arranged to control the actuators 7 to actuate the retractable suspensions 4 to different lengths such that the annular cleaning part 2 tilts. Thus, by coordinating the motions of the actuators 7, the annular cleaning part 2 can be made to tilt in different directions away from its horizontal orientation, in order to alter the angle at which the nozzles 5 impinge on the robot arm 9A, 9B to enhance exposure of the robot surface to the fluid from the nozzles 5. This can be used to reach different parts of the robot arm 9A, 9B. The cleaning apparatus 1 also includes a fluid tight hose 10 for passing of fluid from the fluid supply 6 to the plurality of inwardly directed nozzles 5. The hose 10 is arranged along the outside of the retractable suspensions 4 in a helix formation. With other words, the hose 10 is coiled on the outer side of the retractable suspensions 4. Thereby the hose 10 follows any movement of the annular cleaning part 2 without exposing the cleaning apparatus 1 for an excessive tension. The cleaning apparatus 1 further includes a valve unit 1 1 arranged to control a fluid flow to the at least one nozzle 5. The cleaning control unit 8 is arranged to control the fluid flow to the at least one nozzle 5 by controlling the valve unit 1 1 . The valve unit 1 1 is arranged inside the upper part 3. A fluid line 23 is arranged between the valve unit 1 1 and the fluid supply 6 for passing of fluid, e.g. compressed water or a water mix, to the nozzles 5. A water mix may be water and soap or other kind of washing detergent mixed together. An air line 24 may also be arranged between the valve unit 1 1 and the fluid supply 6 for passing of compressed air by means of the air compressing pump. The cleaning control unit 8 is arranged to switch between passing compressed water or a water mix, passing compressed air, or closing the valve unit 1 1 , by controlling the valve unit 1 1 to different states. By switching from water to compressed air, the cleaning apparatus 1 becomes a high-speed dryer that eliminates water droplets from the surface of the robot arm 9A, 9B and improves hygiene.

Alternatively, a valve unit 1 1 is arranged to the flow path of each individual nozzle 5. Each valve unit 1 1 is individually controllable by the cleaning control unit 8. It is then possible to produce rotating patterns of active nozzles 5 such that not all nozzles 5 need to be active at any given time. This would reduce flow rate requirements on the fluid supply 6. Now turning to the Figs. 4A-4C, where the cleaning apparatus 1 is illustrated in different states. In all states, the upper part 3 is arranged to be suspended or hinged from the attachment part 25 and the annular cleaning part 2 is arranged below the upper part 3 and is arranged to be moved over the robot arm 9A, 9B in a vertical direction. In Fig. 4A the cleaning apparatus is illustrated when it is in a deployed state, thus, the annular cleaning part 2 is outside the upper part 3. By controlling the actuators 7 and thus the retractable suspensions 4, the annular cleaning part 2 can be controlled to take any position between a fully protracted state as illustrated in Fig. 4A where the retractable suspensions 4 are protracted as much as possible, to a fully retracted state as illustrated in Fig. 4B where the retractable suspensions 4 have been retracted such that the annular cleaning part 2 is accommodated inside the upper part 3. As previously explained, the annular cleaning part 2 can also be made to tilt from the essentially horizontal position illustrated in the Figs. 2-4C. In the fully retracted state the hose 10 resides in a compact formation inside the upper part 3. The annular cleaning part 2 is then accommodated into the hollowness of the upper part 3 by retraction of the retractable suspensions 4.

The upper part 3 has an upper hollow conical portion such that water should easily run off the outside and not stay anywhere and eventually cause bacterial growth. The upper part 3 further has a lower hollow tubular portion. The actuators 7, cleaning control unit 8 and valve unit 1 1 reside inside the upper hollow conical portion on a floor 33. The retractable suspensions 4 are passed through holes in the floor 33. Below the floor 33 and inside the hollow tubular portion the annular cleaning part 2 is accommodated in a retracted state.

In Fig. 4C an upper view of the annular cleaning part 2 is illustrated. The annular cleaning part 2 includes a ring shaped body 26. Alternatively, the body 26 may be oval shaped. The body 26 has a height in the vertical direction that allows attachment of a plurality of devices, e.g. the nozzles 5, along the inner side of the body 26, and such that the body can be accommodated inside the upper part 3. The height of the body 26 is thus less than the height of the upper part 3 in the vertical direction. The plurality of inwardly directed nozzles 5 are arranged to the inside of the body 26 and directed towards a center of the annular cleaning part 2. The nozzles 5 are equidistant distributed along the inside of the body 26. The hose 10 interconnects the nozzles 5 and pass fluid to all of the nozzles 5. Here, the number of nozzles 5 is nine, but the number of nozzles 5 may instead be any number from one to twenty. In one embodiment, the annular cleaning part 2 is arranged with at least one inwardly directed ultra violet light source 12. The at least one inwardly directed ultra violet light source 12 is arranged for drying the elongated object. The at least one ultra violet light source 12 is arranged to the inside of the body 26 and directed towards a center of the annular cleaning part 2. The at least one ultra violet light source 12 is arranged to be controlled by the cleaning control unit 8. In Fig. 4C there is a plurality of ultra violet light sources 12 equidistant distributed along the inside of the body 26. The number of ultra violet light sources 12 may be any number from one to twenty. The at least one ultra violet light source 12 may be powered via a wire (not shown) arranged to the cleaning apparatus 1 , or via battery (not shown). The at least one ultra violet light source 12 may be a high power ultraviolet-C light source in the range 275 nm such as a LED. The at least one ultra violet light source can be activated during drying with compressed air. In another embodiment, the annular cleaning part 2 is arranged with at least one image capturing devices 40. The at least one image capturing device 40 is arranged to the inside of the body 26 and directed towards a center of the annular cleaning part 2. The at least one image capturing device 40 is arranged to be controlled by the cleaning control unit 8. In Fig. 4C there is a plurality of image capturing devices 40 equidistant distributed along the inside of the body 26. The number of image capturing devices 40 may be any number from one to twenty. The at least one image capturing device 40 may be powered via a wire (not shown) arranged to the cleaning apparatus 1 , or via battery (not shown). As initially explained, at least one cleaning apparatus 1 can be included in a system 13 for cleaning industrial robots. According to one embodiment, the robot controller 15A, 15B of an industrial robot 14A, 14B to be cleaned is configured to control motion of the industrial robot 14A, 14B to be cleaned, and the cleaning control unit 8 is configured to control the cleaning apparatus 1 , in synchronization with each other. In other words, a computer program is executed on the robot controller 15A, 15B in synchronization with a cleaning program executed on the cleaning control unit 8, such that the robot 14A, 14B positions itself, i.e. the robot arm 9A, 9B, in synchronization with the cleaning program performed by the cleaning apparatus 1 . The robot controller 15A, 15B and the cleaning control unit 8 may handshake a starting time and the progress of their respective programs at certain time intervals, to make sure that the cleaning is executed as intended. The robot controller 15A, 15B may be connected to the cleaning control unit 8 by wire as illustrated in Fig. 7 in order to be able to communicate. Alternatively, the robot controller 15A, 15B and the cleaning control unit 8 may exchange data by wireless means. According to one embodiment, the robot controller 15A, 15B is arranged to send control instructions to the cleaning control unit 8 in order to control the cleaning apparatus 1 .

The robot program of the robot controller 15A, 15B of the industrial robot 14A, 14B to be cleaned includes to position the robot arm 9A, 9B in a vertical pose such that the robot arm 9A, 9B is as straight as possible to facilitate bringing the annular cleaning part 2 over the robot arm 9A, 9B. The robot program may further include various poses such that the attributes (the nozzles 5 etc.) on the annular cleaning part 2 can reach also difficult located parts of the robot arm 9A, 9B.

The cleaning program to be executed by the cleaning control unit 8 includes instructions for positioning the annular cleaning part 2 in various positions and for passing compressed water or water mix through the nozzles 5 in order to wash the robot arm 9A, 9B. According to one embodiment, the cleaning program also includes instructions for passing compressed air through the same nozzles 5 in order to dry the robot arm 9A, 9B. According to a further embodiment, the cleaning program includes instructions for powering the at least one ultra violet light source 12 in order to disinfect the robot arm 9A, 9B. According to a still further embodiment, the cleaning program includes instructions for capturing images of the robot arm 9A, 9B with the at least one image capturing device 40 in order to control that the cleaning has been sufficiently well done. The cleaning program may include instructions to compare the captured images with previously captured images of the same view of the robot arm 9A, 9B and to determine from the result of the comparison if the cleaning was sufficient. If not, the cleaning program may be executed again, or may a shorter version of the cleaning program be executed for only that part of the robot arm 9A, 9B that was not sufficiently clean. The above explained embodiments may be combined, e.g. such that the robot arm 9A, 9B is first washed, then dried, then an image check is made, if ok, the robot arm 9A, 9B is disinfected.

In Fig. 5 a mobile platform 16 is illustrated arranged to transport a cleaning apparatus 1 . The mobile platform 16 has a platform part 27 that is arranged with a propelling device, here three wheels 28. The three wheels 28 make the mobile platform 16 movable in any direction on a floor. Alternatively the propelling device may include an endless belt. The mobile platform 16 is further arranged with propulsion means and steering means (not shown). On the platform part 35 a stand 39 is arranged. The stand 39 has an L-shape with a vertical arm arranged to the platform part 35 and a horizontal arm arranged to the vertical arm. The cleaning apparatus 1 is arranged suspended from the horizontal arm. The stand 39 may be moveable in one or two degrees of freedom, and may thus be arranged to move the vertical arm and/or the horizontal arm e.g. in a telescopic manner. The mobile platform 16 includes a platform control unit 36 including a memory 37 and a processor 38. The memory 37 may be made up of one or several memory units. The processor 38 may be made up of one or several

CPUs. The platform control unit 36 is arranged to control the propelling device to position the mobile platform 16 in front of a robot 14A, 14B of Fig. 1 outside the enclosure 17 of the cell, such that the cleaning apparatus 1 is positioned above a robot 14A, 14B. The stand 39 is thus arranged to reach over the enclosure 17 such that the cleaning apparatus 1 can be positioned vertically over the robot 14A, 14B when the robot 14A, 14B is in an upright vertical position. The mobile platform 16 may be automatically controlled by a program, or may controlled by an operator e.g. by a remote control device (not shown). On the platform part 35 there is arranged a fluid supply 6. The fluid supply 6 may include one water compressing pump and one air compressing pump, for passing of compressed fluid to the nozzles 5 of the cleaning apparatus 1 via a fluid tight hose 10. The platform part 35 may also carry a transportable power supply 22 in order to give power to the propelling device and also to the cleaning apparatus 1 . Alternatively the mobile platform 16 may be powered via a cable (not shown).

Often it is desired to mount a robot on the ceiling, especially if it shall operate directly above conveyors. In Fig. 6 an upper part 3 of an alternative cleaning apparatus 1 is illustrated from above, designed to be used with an industrial robot that is arranged mounted upside down from the ceiling (not show). The upper part 3 here has an annular shape with an axial through hole. The axial through hole has a diameter that is large enough to surround the industrial robot 14A, 14B. When in use, the alternative cleaning apparatus 1 is arranged suspended from the ceiling around the base of the industrial robot. The various parts residing in the upper part 3 as have been previously explained, are now distributed along the upper part 3 along its circular appearance. The other parts of the alternative cleaning apparatus 1 , e.g. the annular cleaning part 2, the retractable

suspensions 4 etc. are the same as have been previously explained.

As previously mentioned, the cleaning control unit 8 and the robot controller 15A, 15B are configured to execute a method for cleaning the industrial robot 14A, 14B. The memory 31 (Fig. 7) of the cleaning control unit 8 includes a cleaning program with instructions, to cause the cleaning control unit 8 to perform parts of the method that will be explained in the following. The memory 30 (Fig. 7) of the robot controller 15A, 15B further includes a computer program with instructions to cause the industrial robot 14A, 14B to perform parts of the method that will be explained in the following. The programs may be stored on computer-readable mediums, and loaded into the memories of the cleaning control unit 8 and the robot controller 15A, 15B. According to one embodiment, a separate computer (not shown) is connected to the cleaning control unit 8 and the robot controller 15A, 15B and is arranged to control both according to a common program incorporating the instructions of the computer program of the robot controller 15A, 15B and the instructions of the cleaning program. The method for cleaning an industrial robot 14A, 14B will now be explained with reference to the flowchart in Fig. 8, and to the illustrations in the remaining figures. The method includes in a step S1 positioning the cleaning apparatus 1 vertically above the robot arm 9A, 9B of the robot 14A, 14B. This may already be done if the cleaning apparatus 1 is arranged suspended from a support structure 21 as illustrated in Fig. 2, or is arranged to the roof as previously explained.

Alternatively, the mobile platform 16 (Fig. 5) transports the cleaning apparatus 1 to the industrial robot 14A, 14B. In a further step S2, the robot arm 9A, 9B is controlled to a vertical pose, as illustrated in Fig. 2. The control unit 15A, 15B of the robot 14A, 14B thus controls the robot 14A, 14B to such a pose. Typically, when production has stopped for the day, the first robot 14A and the second robot 14B are maneuvered to such a pre-programmed vertical pose. The step S1 and S2 may be made in any order, or at the same time. Thereafter the method continues by the step S3 of moving the annular cleaning part 2 over the robot arm 9A, 9B while passing fluid through the nozzles 5. The fluid is here water or mixed water. The three winch motors are activated simultaneously by the cleaning control unit 8 which causes them to lower the annular cleaning part 2 over the robot arm 9A, 9B. At the same time, the cleaning control unit 8 activates the valve unit 1 1 to switch on the flow of water to the fluid nozzles 5. The fluid nozzles 5 spray inwards towards the robot arm 9A, 9B. Spray is contained by the body 26 of the annular cleaning part 2 so that water that does not hit the robot arm 9A, 9B is deflected downwards and falls out of the bottom of the annular cleaning part 2.

While step S3 is performed, the method performs the step S4 including controlling motion of the robot arm 9A, 9B and motion of the annular cleaning part 2 in synchronization in order to clean the robot arm 9A, 9B. As the annular cleaning part 2 descends, the robot 14A, 14B executes pre-programmed maneuvers to improve access of the fluid nozzles 5. This is especially important when cleaning a tool of the robot 14A, 14B, e.g. a gripper 34 (Fig. 2), which is in direct contact with food and therefore likely to have the highest degree of soiling. In this case, axes four, five and six of the robot 14A, 14B would rotate to ensure all surfaces of a gripper 34 are exposed to the fluid nozzles 5. By controlling motion of the annular cleaning part 2 is meant e.g. positioning the annular cleaning part 2 vertically or tilting the annular cleaning part 2. A further step S5 may include lifting the annular cleaning part 2 up from the robot arm 9A, 9B. After step S5 or S4 one or several subsequent steps may be performed. For example may the method continue by again lowering the annular cleaning part 2 over the robot arm 9A, 9B while passing air through the fluid nozzles 5 in order to dry the robot arm 9A, 9B. Thereafter the annular cleaning part 2 is again lift up from the robot arm 9A, 9B. Optionally the image capturing devices 40 are now blown dry by passing air through the nozzles 5 against opposite located image capturing devices 40. The method may now continue and again lowering the annular cleaning part 2 over the robot arm 9A, 9B while capturing images of the robot arm 9A, 9B with the at least one image capturing device 40. The images are transferred to the cleaning control unit 8 e.g. by wireless communication or by wires (not shown) for further processing. If the cleaning is deemed satisfying, then the method may continue and again lowering the annular cleaning part 2 over the robot arm 9A, 9B while irradiating light from the at least one ultra violet light source 12 against the robot arm 9A, 9B in order to disinfect the robot arm 9A, 9B. Thereafter the annular cleaning part 2 is again lift up from the robot arm 9A, 9B, and the cleaning is finished. Alternatively the ultra violet light sources 12 may be activated during drying with compressed air. The annular cleaning part 2 is then retracted into the upper part 3 into a retracted state. The cleaning control unit 8 may communicate to the platform control unit 36, if such a platform is used, that the cleaning is finished and the cleaning apparatus 1 can be transported to the next robot 14A, 14B to be cleaned. In response thereto the platform control unit 36 may transport the cleaning apparatus 1 to the next robot 14A, 14B.

If the cleaning was deemed not satisfying, the method may include to repeat the cleaning steps 3 and 4, or make a smaller cleaning of the area of the robot arm 9A, 9B that was not clean enough. The present invention is not limited to the above-described preferred

embodiments. Various alternatives, modifications and equivalents may be used. Therefore, the above embodiments should not be taken as limiting the scope of the invention, which is defined by the appending claims.