NL2014014B1

NL2014014B1 - Autonomously movable, unmanned vehicle for cleaning a surface in a barn.

Info

Publication number: NL2014014B1
Application number: NL2014014A
Authority: NL
Inventors: Bas Çavlan; Bas Çosku; Anthonius Meijer Niek; Johannes Arjen Van Den Beukel Huibrecht
Original assignee: Triodor Arge
Priority date: 2014-12-19
Filing date: 2014-12-19
Publication date: 2016-10-12
Also published as: WO2016096240A1; EP3232773A1

Abstract

An autonomously movable, unmanned vehicle for use in a barn comprises imaging means (20) for navigation and/or cleaning tasks, a housing (30) for accommodating the imaging means (20), the housing (30) comprising a screen (31) which is transparent for enabling the imaging means (20) to make images through the screen (31), and cleaning means (40) for cleaning at least a portion (36) of the exterior surface (32) of the screen (31).

Description

Autonomously movable, unmanned vehicle for cleaning a surface in a barn

The invention relates in general to an autonomously movable, unmanned vehicle for cleaning a surface in a barn.

The invention relates in particular to an autonomously movable, unmanned vehicle for cleaning a surface in a barn, comprising imaging means for navigation and/or cleaning tasks, and a housing for accommodating the imaging means, the housing comprising a screen which is transparent for enabling the imaging means to make images of the exterior environment through the screen.

It is a well-known fact that barns need to be cleaned on a regular basis, due to the fact that the animals which are accommodated in the barn produce manure and other contaminations. Cleaning a barn may be time-consuming work. In view thereof, autonomously movable, unmanned vehicles equipped with cleaning means for autonomously performing the necessary cleaning actions have been developed. WO2014046540 describes an autonomous vehicle equipped with a scraper to clean the floor of cubicles of dairy cows.. Among other things, W02014046540A1 discloses that the vehicle may be provided with a cleaning quality detector for detecting if, during a cleaning operation, or at the end of a cleaning operation, more manure remains than desired, and that the detector may comprise an optical camera and image recognition software. W00070935A1 also described an autonomous vehicle equipped with cleaning means such as a scraper to the floor of cubicles and also with cleaning means to clean the floor of a stable. Here too, the vehicle can work autonomously and is equipped with camera capable of observing the dirt present on a stable floor and by which it can pilot the unmanned vehicle through the stable. A problem associated with the use of a camera or another type of imaging means in a barn is that it is difficult to maintain clear sight. The fact is that the sight of the imaging means can be disturbed by manure or other types of dirt on the screen of the housing in which the imaging means are situated. In a barn, manure can come from various directions, so that the application of a simple splash guard on the vehicle which is equipped with the imaging means as arranged in the housing is not sufficient for providing total protection from contamination. For example when a cow splatters diarrhea anything within a few meters will be contaminated, and a splash guard for a camera will be useless. Hence, for the known vehicles with camera, human intervention is needed for cleaning the screen in order to maintain or restore proper functioning of the imaging means. W09601040A2 discloses a teat detector for a milking robot. This document recognizes the problem of contamination of the detector to the detriment of the accuracy with which the position of the teats is determined, whilst it is even possible that a positional determination cannot be effected at all. In order to solve this problem, W09601040 discloses a cleaning member for cleaning the detector. This cleaning member is arranged outside the milking box, in connection with the side wall of the milking box. The cleaning member is provided with spraying and/or blowing means for spraying a cleaning liquid or blowing air, respectively, against the screen, thus cleaning the screen. This cleaning operation may be effected after each milking turn or at a lower frequency when it is found that the screen is contaminated less frequently. In any case, putting the detector at an appropriate position with respect to the cleaning member, which is preferably a position outside the milking box, is necessary in order to realize this cleaning operation.

The cleaning method known from W09601040A2 is not suitable for cleaning the screen of a housing in which imaging means are situated on an autonomously movable, unmanned vehicle. . It is an object of the invention to provide a solution to the problem of the functioning of the imaging means of a vehicle getting affected as a result of contamination. This object is achieved by the vehicle as defined in claim 1, which claim provides an autonomously movable, unmanned vehicle for cleaning a floor surface in a barn, the vehicle comprising, a cleaning member for cleaning the floor surface, imaging means, in particular optical imaging means, for use in navigation and/or cleaning tasks, a housing accommodating the imaging means, the housing comprising a screen which is transparent and enables the imaging means to capture images of the exterior environment through the screen, and cleaning means for cleaning at least a portion of the exterior surface of the screen, the cleaning means comprising a blade-shaped scraping element on a support arm, the scraping element having an elongated contacting edge for contacting the screen, driving means for moving the scraping element along the screen and biasing means for biasing the scraping element against the screen thereby realizing pressure contact between the scraping element and the screen at the position of the contacting edge of the scraping element.

According to the invention, imaging means are not only combined with a housing comprising a screen, but also with practical cleaning means for cleaning at least a portion of the exterior surface of the screen. It is noted that the exterior surface is the surface facing outward from the housing, i.e. the surface which is apt to get contaminated over time. The cleaning action to be performed by the cleaning means on the screen does not rely on a use of water and/or cleaning agents, or on blowing air as known from the art. Instead, the basis of the cleaning action resides in scraping the contamination off the screen by means of a movement of a suitable scraping element contacting the screen through a contacting edge, wherein biasing means are foreseen for the purpose of guaranteeing that contact between the scraping element and the screen is contact under pressure, so that it is actually possible to avoid a situation in which the scraping element moves along contaminations without shoving them from the screen, thereby realizing an effective scraping action under all circumstances.

The invention provides a way of keeping clear sight of imaging means mounted on a vehicle for use in a barn. As the invention does not involve a complex construction, the assembly of the imaging means, the housing and the cleaning means as present in the vehicle according to the invention can be denoted as being reliable and robust. Also, there is no need for applying expensive components in the vehicle according to the invention.

Within the framework of the invention, the imaging means may be any type of means for making images. For example, the imaging means may be adapted to process visible light, but is also possible for the vehicle according to the invention to be equipped with imaging means which are adapted to process infrared light or another type of light or energy. For enabling proper functioning of the imaging means while having an arrangement inside a housing, the screen of the housing is transparent, which implies that the screen of the housing is capable of at least allowing the type of light or energy to be registered by the imaging means to pass, i.e. that the screen is permeable to that type of light or energy. In a particular the imaging means may be optical imaging means such as a camera, and the camera may be capable of capturing 2D or 3D images, color or black and white. Suitable image acquisition and image processing means are also provided in order for the vehicle to be able to execute cleaning tasks which may include detecting and recognizing dirt or manure or the like, and/or navigation tasks such as piloting the vehicle.

In an embodiment, the driving means comprise a motor which is arranged inside the housing and a driving shaft which is coupled to the output side of the motor and extends from inside the housing to outside the housing. This provides protection for the motor against the dirty environment and the corrosive properties of in particular manure. Having the motor arranged inside the same housing as the imaging means also yields a practical construction of the assembly of the imaging means and makes it easier to mount to the vehicle and to service when needed. In a further embodiment the driving shaft extends through the screen. When having the shaft extending through the screen of the housing the position of the shaft in relation to the position of the camera in the housing can be chosen such that the cleaning movement of the scraping element is as effective as possible.

In an embodiment the driving shaft comprises several sections and an end section connects to the support arm. A thus sectioned driving shaft allows more flexibility in assembling the cleaning means into the housing.

According to a further aspect of the embodiment having the shaft extending through the screen of the housing, the biasing means are arranged inside the housing, between a position on the driving shaft and a fixed basis in the housing. By positioning the biasing means inside the housing protection for biasing means against the dirty environment and the corrosive properties of in particular manure is safeguarded.

Advantageously, the biasing means comprise an extension spring. In this embodiment, the biasing means are adapted to pull the scraping element against the screen from the interior side of the screen. Also the extension spring is protected from manure and thus there is no risk of dried up manure blocking the spring windings and impeding the biasing function of the spring.

In another practical embodiment of the vehicle according to the invention, the biasing means are arranged between the support arm and the scraping element. This is means that the biasing means are on the outside of the housing. The advantage of the ease of repairing or interchanging of the biasing means e.g. together with the scraping element outweighs the drawback that the biasing means will become dirty.

Advantageously, the biasing means may comprise a spring-loaded hinge. In this embodiment, the biasing means are adapted to press the scraping element against the screen from the exterior side of the screen.

The spring-loaded hinge has as advantage that the spring is a torsion spring and the biasing force is lead in a very direct manner from the hinge-plate to the scraping element. Another advantage is that the torsion spring may be mounted inside the hinge cylinder and thus be protected from contact with dirt such as manure.

In an embodiment the vehicle according to the invention comprises controlling means for automatically activating the driving means of the cleaning means. This means that instead of having continuous action of the driving means or manual activation thereof by a user, the activation can be done automatically and thus intelligently controlled. Unnecessary wear of the parts of the cleaning means with continuous activation or bad vision when the cleaning means are not activated often enough, can thus be prevented. Also, power can be saved when the driving means are not continuously operated, which is advantageous in view of the fact that it is common use for an autonomously movable, unmanned vehicle to rely on battery power for its functioning.

According to an aspect of this embodiment, the controlling means are adapted to activate the driving means at at least one of the start and the ending of a cleaning task performed by the vehicle.

When the driving means of the cleaning means are activated before the vehicle starts a cleaning action it is assured that the vision means will have proper view of the area where the vehicle will perform its cleaning action. When the driving means are activated at the end of the cleaning action it is ensured that manure fell on screen during the cleaning action will not get the opportunity to dry up and cake to the screen. Also in particular when series of successive cleaning actions are performed, the screen is clean for the next action. According to another aspect of this embodiment , the controlling means comprise a timer for activating the driving means at predetermined time intervals. Often cleaning is done at predetermined time intervals in which case it is advantageous to also ensure that the screen is cleaned at time intervals. It can then be ensured that prior to beginning or at the end of a timed cleaning action, the screen is cleaned.

According to yet another aspect of this embodiment, the controlling means are adapted to process a signal from the imaging means, and wherein the controlling means are adapted to activate the driving means when the signal indicates that the screen is dirty. For example the attenuation and the scattering of the light can be determined, if it is over a certain threshold the driving means can be actuated. Now the driving means are only activated, and thus a cleaning action on the screen of the vision means is only performed, when such action is determined to be necessary. From the image acquired by the imaging means parameters can be used to determine when the screen is deemed to dirty and needs to be cleaned. Dirt can be determined by using an algorithm in the image processing for determining artefacts in the image. Alternatively images of a known structure can be taken and compared with a calibration image of the same structure. The driving means can then be activated when the imaged deviates too much from the calibration image.

Advantageously, the signal represents a value which is indicative of a distance of an object to the imaging means (20) and the driving means is activated when the value is less than a predetermined reference value.

Hence, this option relies on detection of objects which are in fact contamination of the screen. The controlling means are be adapted to process a signal from the imaging means, and to activate the driving means when the presence of an object closer than a predetermined reference distance to the imaging means is found. This will work because dirt will be on the screen whereas "real objects" such as e.g. animals, structures of the barn and the like are not on the screen.

In an embodiment, the scraping element (41) has an inclined orientation with respect to the screen (31), an angle between the scraping element (41) and the screen (31) being in a range of 35° to 55°. In this way, an effective scraping action can be realized, as it is possible to let the scraping element encounter a contamination on the screen in a gradual fashion, first with the contacting edge for breaking adherence between the contamination and the screen and then with an increasing extent of blade-shaped material for shoving the contamination to another location. In an embodiment of the invention, the scraping element is made of stainless steel and the screen is made of glass. Other materials are also possible within the framework of the invention.

Within the framework of the present invention, the scraping element may have any suitable shape and can be moved along the screen in any suitable way. In a further embodiment of the invention, the scraping element is rotatable about a rotation axis intersecting the screen, the contacting edge (43) extending in a radial direction with respect to the rotation axis.. Hence, when the driving means are activated, the scraping element is moved along the screen as a clock hand, whereby a portion of the exterior surface of the screen having a circular periphery is cleaned. The scraping element may be driven such as to make a full rotation, i.e. a rotation of 360°, which is appropriate in case the scraping element has an inclined orientation with respect to the screen as mentioned in the foregoing, or may be driven such as to only cover an area of the screen in front of the imaging means, which may be smaller than the area associated with a full rotation of the scraping element.

By having a rotating movement of the scraping element along the screen, it is achieved that a rim of dirt is obtained as a delimitation of the cleaned area over time. The presence of such rim may involve a guarding effect, so that contamination of the cleaned area is prevented to some extent, which is a surprising effect of the invention contributing to the desired end result: keeping the screen clean, at least a portion of the screen which is present in front of the imaging means, so that the functioning of the imaging means can be optimal at all times.

It follows from the foregoing that when it comes to cleaning, two functions can be found in the vehicle according to the invention. In the first place, the vehicle is adapted to clean a surface in a barn, which may be the floor of a cubicle, for example. This is the general function of the vehicle being equipped with suitable floor cleaning means and which may be realized in any suitable manner. Furthermore, at the level of the vehicle itself, there is another cleaning function, which is associated with the imaging means as present in the vehicle for use in navigation and/or cleaning tasks, and which is particularly aimed at keeping a screen of a housing for accommodating the imaging means clean. This cleaning function is based on using a scraping element and moving the scraping element across the screen while pressing the scraping element against the screen from the outside of the housing or pulling the scraping element against the screen from the inside of the housing.

The invention will now be explained in greater detail with reference to the figures, in which equal or similar parts are indicated by the same reference signs, and in which:

Figure 1 diagrammatically shows a top view of a barn in which cubicles and a feed fence are present, wherein a vehicle according to the invention, which is used in the barn for performing cleaning actions in the barn, is also depicted;

Figure 2 diagrammatically shows a side view of an embodiment of the vehicle according to the invention, which is adapted to displace manure;

Figure 3 diagrammatically shows a front view of a housing which is part of the vehicle according to the invention, which accommodates a camera and which has a screen positioned in front of the camera, wherein a cleaning arrangement for cleaning a portion of the exterior surface of the screen is also depicted;

Figure 4 diagrammatically shows a perspective view of components of the cleaning arrangement shown in figure 3;

Figure 5 diagrammatically shows a sectional view of the housing accommodating the camera, wherein an alternative cleaning arrangement for cleaning a portion of the exterior surface of the screen of the housing is also depicted.

Figure 1 shows a top view of a barn 100 for accommodating animals 1, which may be dairy animals such as cows. In general, a barn 100 may be of any practical design. Often, as is the case in the shown example, the barn 100 has a contaminated section 101 and a clean section 102, which are separated by a feed fence 103. In the clean section 102, food for the animals 1 is distributed along the feed fence 103. The animals 1 are present in the contaminated section 101 and can reach the food in the clean section 102 by putting their heads through the feed fence 103. In the contaminated section 101, cubicles 104 are present for the animals 1 to have an individual area in the barn 100 where they can be at ease.

Due to the presence of the animals 1 in the contaminated section 101, the barn floor 105 gets contaminated by manure and the like in that section 101. It is important that cleaning actions are performed in the contaminated section 101 on a regular basis, of the barn floor 105 where the animals walk and also the cubicle floor 104 . To that end, an autonomously movable, unmanned vehicle 10 is provided, which is adapted to clean a floor surface, and which is adapted to navigate through the contaminated section 101 in order to perform a cleaning action of a floor surface at any appropriate area in the contaminated section 101. In particular, the vehicle 10 comprises navigation means for enabling the vehicle 10 to navigate along a route and safely move through the contaminated section 101 without getting lost and without colliding with an animal 1 or a structural obstacle such as a partition wall 106 as present between two cubicles 104. Typically such an autonomous vehicle has battery operated motors such as for its drive wheels, and thus a charging station for charging the batteries is also provided in the barn. The vehicle also uses its navigation means to find the charging station. The navigation means may comprise imaging means such as optical imaging means or a camera. The camera may be a 2D or 3D camera.

Figure 2 shows an embodiment of the vehicle 10 for performing cleaning tasks in the contaminated section 101. In particular, the vehicle 10 is adapted to clean the barn floor 105 by displacing manure. Among other things, the vehicle 10 comprises a frame supported on wheels 12, and a casing 13 arranged on the frame for accommodating several functional components of the vehicle 10. The vehicle also comprises a wall following means 11 which is used in the navigation along walls of the barn. At the bottom side in a normal orientation of the vehicle 10 as shown in figure 2, a manure slide 14 is arranged, which extends down from the frame to floor level. When driving the vehicle rests on the wheels and the manure slide 14. Hence, when the vehicle 10 performs a movement, manure and possible other dirt lying on the barn floor 105 are encountered by the manure slide 14 and are displaced along with the vehicle 10. On the basis thereof, the vehicle 10 is suitable to be used for displacing manure and possible other dirt from an original area to a collection area for discharge of the manure and possible other dirt. Or alternatively to push the manure through slots in the barn floor 105 into a manure cellar below the barn floor 105.

The vehicle 10 comprises at least one camera 20 which is adapted to make and acquire images of the environment of the vehicle 10. The vehicle 10 further comprises a controller (not shown) or the like for interpreting the images and applying information contained in the images for the purpose of realizing at least one function relying on visual detection such as navigation of the vehicle 10 through the contaminated section 101 or determination of the actual presence of contamination. The camera 20 may be of any suitable type, such as a 2D or a 3D camera, and may be suitable for visible or infrared light. In any case, the camera 20 is situated inside a housing 30 comprising a transparent screen 31, wherein the camera 20 is positioned behind the screen 31, such that the lens of the camera 20 is capable of receiving light from the environment through the screen 31. In the shown example, the housing 30 is arranged on the casing 13 of the vehicle 10, which does not alter the fact that another position of the housing 30 on the vehicle 10 is feasible as well.

Due to the fact that the vehicle 10 is present inside the contaminated section 101 of the barn 100, the vehicle 10 gets contaminated over time. In order to avoid situations in which the functioning of the camera 20 is disturbed by contamination of the exterior surface 32 of the screen 31, the vehicle 10 is equipped with a cleaning arrangement 40 for cleaning a portion of the exterior surface 32 of the screen 31, as can be seen in figure 3 showing a front view of the housing 30 comprising the screen 31 and accommodating the camera 20 which is visible through the screen 31. Details of the cleaning arrangement 40 can be seen in figure 4, in which a perspective view of components of the cleaning arrangement 40 as present outside of the housing 30 is shown.

As best seen in Figures 3 and 4, the cleaning arrangement 40 comprises a blade-shaped scraping element 41 on a support arm 42. The scraping element 41 has an elongated contacting edge 43 for contacting the screen 31. The scraping element 41 is coupled to the support arm 42 through a holder 44 and a carrier element 45, wherein the holder 44 serves for tightly enclosing a portion of the scraping element 41 and leaving another portion of the scraping element 41, especially a portion being situated at the side of the screen 31 and having the contacting edge 43, exposed, and wherein the holder 44 is suspended from the carrier element 45. In the shown example, the support arm 42 comprises an end portion 46 having two legs 46a, 46b, wherein the carrier element 45 is arranged at a position between the legs 46a, 46b and connected to the at least one of the legs 46a, 46b through suitable connection means such as a pin-like member 47 extending through aligned holes of the carrier element 45 and the relevant leg(s) 46a, 46b.This mounting of the carrier element allows some slight pivotal movement, which enhances the ability of the scraping element 41 to follow the screen surface 31 when moving along the screen. For the purpose of pressing the scraping element 41 against the screen 31, such that pressure contact between the scraping element 41 and the screen 31 is realized through the contacting edge 43 of the scraping element 41, the holder 44 and the carrier element 45 are interconnected through a spring-loaded hinge 50.

The support arm 42 is coupled to the output side of a motor 33 (shown in figure 2) which is arranged inside the housing 30, by means of a driving shaft 34 extending through the screen 31. A seal 35 is provided for sealing the screen 31 at the position where it is intersected by the driving shaft 34. The seal 35 may be any seal which is known to be effective in constructions comprising a rotatable shaft and an element having a hole for allowing the shaft to extend through the element.

The driving shaft 34 is rotatable about a rotation axis which coincides with its longitudinal axis. When the driving shaft 34 is rotated by means of the motor 33, the assembly of the scraping element 41, the support arm 42 and all intermediate components as described in the foregoing are forced to perform a movement. In particular, the contacting edge 43 of the scraping element 41 extends more or less in a radial direction with respect to the rotation axis. When seen in the direction of movement, see clockwise arrow in figure 3, the contacting edge 43 of the scraping element lies in front of the rotation axis of the driving shaft. As a result, when the driving shaft 34 is rotated, the contacting edge 43 sweeps along the screen 31, covering an annular area 36 of the exterior surface 32 of the screen 31. The dirt encountered by the contacting edge of the scraping element is moved radially outward. In the process of each rotation of the scraper, if a contamination is present on the in the annular area 36, such contamination will be scraped off the screen 31 by means of the moving scraping element 41 and will move radially outwardly along the scraping element 41, while remaining in front of the element 41, until the contamination has reached the radial outer end of the element 41 and is deposited at the outer circumference of the annular area 36. For the sake of illustration, the annular area 36, which will hereinafter be referred to as cleaned area 36, is delimited by outer circumferential and inner circumferential rims which are indicated by means of the dashed circular lines in figure 3. The inner dashed circular line having a smaller diameter then the outer circular line and lying adjacent the axis of rotation and the driving shaft 34. As time passes, the deposited contaminations may dry up and form an annular rim or ring surrounding the cleaned area 36. The rim of caked, dried up manure has been found to be advantageous because it constitutes a barrier around the cleaned area 36.lt will not negatively effect the images made by the camera because when it grows over a certain thickness and/or height by the dirt that is deposited on the inside of the outer circumferential rim, it will break and fall off the screen.

In order to have a smooth and effective scraping process by means of the cleaning arrangement 40, the blade-shaped scraping element 41 has an inclined orientation with respect to the screen 31. In the shown example, an angle between the scraping element 41 and the screen 31 is about 45°, wherein the contacting edge 43 of the scraping element 41 is at the front as seen in a direction of movement of the scraping element 41 along the screen 31, which is indicated by means of a bent arrow in figure 3, and the rest of the scraping element 41 is inclined upward as seen in a direction opposite to the direction of movement. In this way, it is achieved that when the scraping element 41 moves along the screen 31, the scraping element 41 does not only act like a shove, which would be the case when the scraping element 41 would be orientated perpendicular to the screen 31, but also acts like a kind of knife at the level of contact to the screen 31 for breaking adherence between contaminations and the screen 31.

It is noted that with the inclined orientation of the scraping element 41 as explained in the foregoing, the direction of movement of the scraping element 41 along the screen 31 is automatically determined, as it is advantageous to have the contacting edge 43 in a leading position and not in a trailing position. That does not alter the fact that embodiments are feasible in which it is appropriate to move the scraping element 41 in a reciprocating fashion along the screen 31, for example. In the case as illustrated in figures 3 and 4, when the cleaning arrangement 40 is operated, the cleaned area 36 having the annular shape as mentioned earlier is realized. In this case, a large portion of the entire screen 31, which has a square periphery in the shown example, is covered during cleaning, while only a portion of the cleaned area 36 is in front of the camera 20.

In principle, it is possible to operate the arrangement 40 for cleaning the screen 31 of the housing 30 the entire period that the vehicle 10 is moved and performs a cleaning action on the barn floor 105 in the process, but it is preferred to operate the cleaning arrangement 40 only from time to time. Various algorithms are feasible for controlling the operation of the cleaning arrangement 40. For example, the cleaning arrangement 40 may be activated to let the scraping element 41 make a predetermined number of turns along the screen 31 every time the vehicle 10 finishes a process of cleaning the barn floor 105 at the position of a cubicle 104.

It follows from the foregoing that two key features of the cleaning action performed by the cleaning arrangement 40 during operation thereof are that contaminations are removed from the screen 31 under the influence of scraping, and that the element 41 which is used for realizing the actual scraping process is biased against the screen 31. In the example as illustrated in figures 3 and 4, the scraping element 41 is continually pressed against the screen 31 under the influence of the spring-loaded hinge 50. An alternative construction is illustrated in figure 5 and will be elucidated in the following.

Figure 5 clearly shows that the cleaning arrangement 40 comprises a motor 33 which is arranged inside the housing 30, that the scraping element 41 and the support arm 42 are arranged outside the housing 30, and that the support arm 42 is coupled to the motor 33 by means of a driving shaft 34 extending through the screen 31. A notable difference between the construction shown in figure 5 and the construction shown in figures 3 and 4 resides in the fact that the construction shown in figure 5 does not comprise a spring-loaded hinge 50 for pressing the scraping element 41 against the screen 31 from the exterior side of the screen 31. Instead, for the purpose of biasing the scraping element 41 against the screen 31, an extension spring 55 is used, which is situated inside the housing 30 and is thereby arranged to pull the scraping element 41 against the screen 31 from the interior side of the screen 31. In particular, the extension spring 55 is arranged between a position on the driving shaft 34 and a fixed basis 56 in the housing 30, wherein the spring 55 is arranged such as to surround the driving shaft 34. Apart from the way in which the scraping element 41 is biased against the screen 31, the construction shown in figure 5 has many aspects in common with the construction shown in figures 3 and 4. Hence, when the motor 33 is actuated, the driving shaft 34 is rotated about a rotation axis coinciding with its longitudinal axis, as a result of which the support arm 42 is made to perform a rotary movement about the rotation axis as well, resulting in a movement of the scraping element 41 along the screen 31. In the process, the screen 31 is effectively cleaned, as contaminations which may be present on the screen 31 are scraped off the screen 31 as soon as they are encountered by the scraping element 41. As the scraping element 32 is biased against the screen 31, a situation in which the scraping element 32 might be pushed away from the screen 31 by a contamination which is really stuck to the screen 31 is avoided. Hence, the biasing function of the extension spring 55 shown in figure 5, the spring-loaded hinge 50 shown in figure 4, or any possible other suitable biasing means contributes to the effectiveness of the cleaning action to be performed by the cleaning arrangement 40 on the screen 31. All in all, a practical way of cleaning the screen 31 is provided, on the basis of which optimal functioning of the camera 20 can be guaranteed.

It will be clear to a person skilled in the art that the scope of the invention is not limited to the examples discussed in the foregoing, but that several amendments and modifications thereof are possible without deviating from the scope of the invention as defined in the attached claims. While the invention has been illustrated and described in detail in the figures and the description, such illustration and description are to be considered illustrative or exemplary only, and not restrictive.

Claims

An autonomously movable unmanned vehicle (10) for cleaning a floor surface (105) in a shed (100), the vehicle comprising: - a cleaning component for cleaning the floor surface; - imaging means (20), in particular optical imaging means, for use in navigation and / or cleaning tasks; - a housing (30) that accommodates the imaging means (20), wherein the housing comprises a screen (31) that is transparent to enable the imaging means (20) to transfer images of the external environment through the screen (31) to receive; and - cleaning means (40) for cleaning at least a portion (36) of the external surface (32) of the screen (31), the cleaning means (40) comprising - a blade-shaped scraper element (41) on a support arm (42), wherein the scraper element (41) has an elongated contact edge (43) for contacting the screen (31); - biasing means (50, 55) for biasing the scraper element (41) against the screen (31), thereby effecting pressure contact between the scraper element (41) and the screen (31) at the area of the contact edge (43) of the scraper element (41).

Vehicle (10) according to claim 1, wherein the drive means (33, 34) comprise a motor (33) arranged in the housing (30), as well as a drive shaft (34) coupled to the power side of the motor ( 33) and extends from inside the housing (30) to outside the housing (30).

The vehicle of claim 2, wherein the drive shaft (34) extends through the screen (31).

The vehicle (10) according to claim 2 or 3, wherein the drive shaft (34) comprises several sections, and wherein an end section is connected to the support arm (42).

The vehicle according to any of claims 2-4, wherein the biasing means (55) are arranged within the housing (30), between a position on the drive shaft (34) and a fixed base (56) in the housing (30).

The vehicle of claim 5, wherein the biasing means comprise a tension spring (55).

The vehicle (10) according to any of claims 1-4, wherein the biasing means (50) are arranged between the support arm (42) and the scraper element (41).

The vehicle (10) of claim 7, wherein the biasing means comprise a spring-loaded hinge (50).

Vehicle (10) according to any of claims 1-8, comprising control means for automatically switching on the drive means (33, 34).

Vehicle (10) according to claim 9, wherein the control means are adapted to switch on the drive means at at least one of the beginning and the end of a cleaning task performed by the vehicle (10).

The vehicle (10) of claim 9, wherein the control means comprises a timer for switching on the drive means (33, 34) at predetermined time intervals.

The vehicle (10) according to claim 9, wherein the control means are adapted to process a signal from the image-forming means (20), and wherein the control means are adapted to switch on the drive means (33, 34) when the signal indicates that the screen is dirty.

The vehicle (10) of claim 9 [will be: 12, vert.], Wherein the signal represents a value indicative of a distance of an object from the imaging means (20) and the drive means are turned on when the value is less than a predetermined reference value.

The vehicle (10) according to any of claims 1-13, wherein the scraper element (41) is inclined with respect to the screen (31), wherein an angle lies between the scraper element (41) and the screen (31) in a range from 35 ° to 55 °.

The vehicle (10) of any one of claims 1-14, wherein the scraper element (41) is rotatable about an axis of rotation that intersects the screen (31), the contact edge (43) extending radially with respect to the axis of rotation .