FR2599772A1 - Robot for the maintenance of buildings - Google Patents

Abstract

The invention relates to a robot for the maintenance of buildings, of the type comprising a connection cable 16 which connects it to a control and garaging station. This robot is characterised in that it comprises a sliding cross in which there can move, at right angles and in a controlled manner, one leg of a first L-shaped fastening angle section 20 and one leg of a second L-shaped fastening angle section 21, the said angle sections, whose planes are substantially parallel, being provided with grasping members; means for switching the latter on and off; means for moving the grasping members of one 21 of the said angle sections perpendicularly to the plane of this angle section; and means firmly attached to the said angle sections 20, 21 for cleaning surfaces to be maintained by spraying and scraping. Application to the cleaning of tall buildings.

Description

 The present invention relates to a mobile robot intended to maintain tall buildings which are coated with glass, windows or other non-porous surfaces over most of their height. The maintenance of such buildings includes various operations such as washing windows and blind parts, as well as inspecting facade or sealing joints.

 All these works are carried out by operators who are window washers or facade inspectors and whose work is dangerous and difficult because of the use of suspended scaffolding. On the other hand, the ease of cleaning a window is a function of the frequency of washes, because the surface tension of a drop of water deposited on a window is significantly modified by the deposition of microscopic acid dust which are precipitated by the surrounding air of cities. As a result, on a clean glass, the drop of water spreads forming a small wetting angle with the glass, so that a simple neoprene squeegee is effective. On a dirty glass, on the contrary, the water concentrates by forming a large wetting angle, which makes the squeegee much less effective.

It is therefore advantageous to clean the facade of buildings once a week to avoid fouling of the windows and aging of the panels, which can only be achieved economically if one can avoid using an operator, and therefore , if the work is carried out by a robot.

 There is a device for cleaning facades which was developed in Japan and which consists of a brushing device of 840 kg suspended by cables and held in position against the glass of the building by means of rails integrated into the facade, however that an operator steer the device from a control cabin located on the roof. The price of this device and the fact that it requires the use of rails integrated into the facade considerably limit the advantage of this invention.

 In the European patent EP-0.084.012, the inventor proposed a robot capable of treating surfaces like the hulls of ship and the tanks of hydrocarbons which moves by its own means thanks to two mobile equipments each provided with means of hanging on the surface to be cleaned.

 Until then, and despite numerous tests by various research teams, the weight of such climbing robots was always greater than 73 kg, which is incompatible with the maximum permissible weight for washing the windows of a high-rise building. In addition, the number of control members and sensors of such a robot makes the price prohibitive for the maintenance of buildings.

 The present invention aims to provide a light and reliable mobile robot which is capable of performing functions of washing, cleaning and inspecting the facades of tall buildings, without it exceeding a weight of 22 kilograms.

 According to the invention, this object, and others which will appear subsequently, is achieved by means of a robot of the type comprising a connecting cable which connects it to a control and storage station, and which is characterized by the fact that it comprises a sliding cross in which can move, at right angles and in a controlled manner, a branch of a first L-shaped mounting bracket and ur, branch of a second L-shaped mounting bracket, these brackets, the planes of which are substantially parallel, being provided with gripping members; means for activating and deactivating these gripping members at will; means for moving the gripping members of one of the brackets in question perpendicularly to its plane this and means secured to the brackets for cleaning by spraying and scraping the surfaces to be maintained.

 We understand that it is thus possible to move the robot step by step in two perpendicular directions: it suffices for this to stick one of the hooking brackets on the surface to be cleaned by means of its gripping members and to move from the sliding cross the other bracket whose gripping members have been deactivated. We then glue the latter on the surface, we deactivate the gripping members of the other bracket and we bring it back to the first, so that the two brackets, and therefore the whole robot, have moved one step . The process can then start again and, depending on whether the angle arm sliding in the cross is, for example, horizontal or vertical, the movements of the robot are horizontal or vertical. In addition, the device specified above makes it possible to obtain six degrees of freedom with only five control devices, which makes it possible to produce a light robot whose weight is compatible with the mechanical resistance of a window.

 According to an advantageous embodiment of the present invention, the robot, when it is in the vertical operating position, is presented as follows: its first bracket has a horizontal branch which passes through the sliding cross and, at a end of this branch, a vertical branch extending downward, while its second bracket has a vertical branch which passes through the sliding cross and, at the upper end of this branch, a horizontal branch extending in the opposite direction to the vertical branch of the first square.

 This arrangement ensures maximum stability for the robot according to the invention, even when one of the attachment brackets does not adhere to the surface to be cleaned because its gripping members have been deactivated.

 On the other hand, these gripping members are advantageously pneumatic or magnetic suction cups, depending on the nature of the surfaces to be cleaned, these suction cups being arranged, preferably in groups of two, in the vicinity of the apex and the two ends of the right angle. formed by the L-shaped brackets specified above.

 In addition, these suction cups are preferably provided with two threshold sensors, the first threshold making it possible to detect the contacting of the suction cup with the surface to be cleaned, and the second announcing that the suction cup is well attached to this surface.

 Regarding the means specified above to move the gripping members of one of the brackets of the robot perpendicular to its plane, it is advantageously cylinders integral with the bracket in question and perpendicular to its plane comprising a motor which rotates a threaded rod screwed into a finger of polygonal section, the latter sliding in a passage of corresponding shape which prevents it from rotating and carrying at least one gripping member, for example a suction cup, at its end opposite to the threaded shaft.

 It is clear that the controlled rotation of the motor of this jack, and therefore of the threaded rod, only displaces the finger axially, and therefore the suction cup or suction cups concerned which are integral with it, since the finger in question, and therefore the or the suction cups are prevented from rotating.

 Preferably, the means specified above for cleaning by spraying and scraping the surfaces to be maintained include elastic scraper blades associated with spraying ramps and integral with the attachment brackets of the robot, these scraper blades being preferably arranged, one horizontally and two others vertically at the end of the assembly formed by the attachment brackets, which prevents the robot from marking the surface to be cleaned with the imprint of its suction cups.

 Advantageously, that of the attachment brackets of the robot which does not carry jacks is provided with a repositioning sensor which makes it possible to know the drift of the robot in rotation and along the two horizontal and vertical axes.

 According to a particular embodiment of the present invention, the two branches of one of the attachment brackets of the robot are articulated one on the other, the angle formed between them being able to be fixed at a predetermined value at l using control means. Although the absence of this articulation does not prevent the robot from rotating around an axis perpendicular to the surface to be cleaned, as will be explained below, its presence allows rotations more important, which is extremely useful when you want, for example, to progress on a geode.

 On the other hand, an inclinometer is advantageously mounted on the connecting cable which connects the robot to its control and storage station, this device being mounted a short distance from the robot to control the unwinding or winding of the cable when 'it is no longer horizontal.

 We understand that this arrangement allows to maintain a constant distance from the robot the loop which forms at the bottom of the cable and which includes the inclinometer in the middle.

This avoids overloading the robot with an excessive cable weight, the strand between it and the bottom of the loop remaining of a constant length.

 Preferably, the connection cable specified above is provided with a ballast which contains the electronic interface of the robot and / or the power amplifiers of the robot control devices and / or a buffer tank for the washing liquid and / or a compressed air buffer tank, the ballast in question being coated with a compressible shock absorbing envelope.

 Advantageously, the robot control and storage station according to the invention comprises in particular a cabinet, a winch for winding and unwinding the connecting cable which connects the robot to this station, a power power supply, a compressor d air, a control computer, a mixing tank and a dosing pump for the cleaning product and an anemometer. The latter is used to check that the wind speed is lower than a predetermined value which is recorded in the control computer and which corresponds to the limit value of the wind speed which is compatible with the proper functioning of the robot.

 Finally, the robot according to the invention preferably comprises a crossing device which allows it to climb the facade devices, as well as the crossing of the ventilation grids and free bays.

The description which follows, and which has no limiting character, will make it possible to understand clearly how the present invention can be put into practice. It should be read in conjunction with the accompanying drawings, among which
- Figure 1 shows a top view of the robot according to the invention
- Figure 2 shows an elevational view of the control and storage station of this robot
- Figure 3 shows an axial sectional view of a suction cup cylinder fitted to the robot of the invention
- Figure 4 shows a perspective view of the robot in question in the vicinity of its sliding cross
- Figures 5 and 6 show schematically and in perspective the electronic control devices located, respectively, in the control station of Figure 2 and in the robot itself or in its immediate vicinity, as well as the connections which connect them
FIG. 7 represents a perspective view of the top of a mounting bracket for the robot according to the present invention in the case where its two branches are articulated relative to each other
- Figure 8 shows a partial perspective view of a cleaning member of the robot according to the invention; and
- Figures 9 to 19 are schematic top views illustrating the operating mode of the device according to the invention during a step to the right (Figures 9 to 16) or down (Figures 17 to 19).

 The robot according to the present invention comprises four assemblies which will be described successively below and which are 1. A control and storage station which is installed on the roof of the building to be cleaned, which contains the control and power supply to the robot and which is likely to house the latter when it is not in use 2. A connecting cable between the robot and its control and storage station 3. The building maintenance robot itself; and: 4. Facade crossing devices if the latter is not flat.

 In the following description, and unless otherwise indicated, it will be assumed that the robot according to the invention is in the normal operating position on a surface to be cleaned, which gives meaning to expressions such as "horizontal" or "vertical".

 The control and storage station is shown in Figure 2 and it consists of the following elements 1. A cabinet 1 made of sheet metal or plastic which is fitted with a pivoting door 2 or a sliding door to protect the robot when it is at rest and put it in position when it leaves or arrives 2. A winch 3 for winding the connecting cable which connects the control station to the robot, this winch can be a winch with conventional vertical winding or a horizontal winding winch fitted with unwinding arms. Such devices are well known and they are used in particular for cables of underwater robots.

3. An electrical power supply 4 for the assembly formed by the robot and its control station, this supply comprising an isolation transformer, a circuit breaker and possibly an installation of backup batteries 4. An air compressor 5 intended to supply compressed air for the suction cups of the suction cups of the robot which will be described later 5. A computer 6 for controlling the robot. As can be seen in FIG. 5, this computer comprises a main card 7 of IBM-PC computer or the like which is equipped with a memory card 8, a modem card or a separate modem, a card screen 10, of an input / output card 11 and of an input / output card provided with an adapter 12 for the optical fibers. A screen and a keyboard 13 are portable peripheral elements which are provided by the operator who is responsible for the maintenance and programming of the robot 6. A mixing tank 1 and a metering pump for the window cleaning product which is generally alcohol vinegar dosed at 54 in water 7. An anemometer 15 intended to check whether the wind speed is lower than a limit value recorded in the computer 6 and which corresponds to the maximum value compatible with the correct functioning of the robot.

 For its part, the connecting cable connecting the robot itself (Figure 1) and its control and storage station comprises the following elements 1. Three electrical conductors intended to supply power to the robot's control members and also to supply its interface circuits 2. Two optical fibers which carry information from the sensors which will be described later from the robot to the computer 6 3. A tube which allows the cleaning liquid to reach the robot 4. A general sheath around the elements listed above, this sheath being under air pressure and simultaneously serving as cond-uit of compressed air at low pressure between the robot and its control station 5. An inclinometer 17 intended to control the progress and the winding of the winch of the connecting cable on the roof of the building, this device being located in the center of a loop approximately one meter from the robot. It is essential that the robot only supports about one meter of the connecting cable, because thus the most important part of the latter is carried by the winch 3 and not by the robot itself, as has been explained more -high 6. A weight 18 for ballasting the connecting cable 16, this weight being coated with a neoprene foam protection to avoid any violent impact of the ballast 18 against the glass to be cleaned.

 The essential element of the robot itself is a sliding cross 19 (FIG. 4) which is the center of its mechanical part and which can be made of glass fiber or aluminum. The cross 19 receives the horizontal branch 201 of a first attachment or gripping angle 20 in the shape of an L, branch which is extended by a vertical branch 202 extending downwards. The cross 19 also receives the vertical branch 211 of a second attachment bracket 21 which is extended at its upper end by a horizontal branch 212 extending in the opposite direction to the vertical branch 202 of the first bracket (see for example Figure 9). The brackets 20 and 21 can be made of plastic or aluminum and they are provided with a series of suction cups 22 in neoprene or "silastene" which constitute the means of fixing the robot on the wall to be washed. .

Advantageously, there can be three series of two suction cups 22 coupled together via a rigid plate, but a different number of suction cups can be installed depending on the porosity or the type of support that one wishes to treat, it being understood however that the arrangement of the suction cups 22 along two brackets is essential for the proper functioning of the robot, the stability of the latter being proportional to the lengths A and B of FIG. 1. On the other hand, it is also possible to equip the magnetic suction cup robot instead of vacuum suction cups for the treatment of metallic surfaces with magnetic properties.

 The bracket 21 is provided with at least three electric jacks 23 which are intended to distance and bring this bracket closer to the surface on which the robot is progressing.

One of these jacks is shown in FIG. 3. It comprises a brushless electric motor 38 mechanically coupled to a decoder or to a resolution device, the shaft 40 of this motor being coupled by means of a belt. notched 41 to a threaded rod 42. A ball screw 43 is integral with a triangular push rod 44 guided by two ball or needle bearings 45 on each of the planes of the push rod 44, the latter being finally made integral of a plate 46 for supporting the suction cups 22. As already indicated above, this arrangement makes it possible to move the suction cups 22 perpendicular to the plane of the bracket 21 when the motor 38 is rotated.

 On the square without jacks 20, the plate 46 is fixed by means of a plastic spacer a few millimeters thick.

 As seen in Figure 4, the sliding movements of the brackets 20 and 21 of a brushless electric motor 49 coupled with an encoder or the like whose hollow shaft is provided with a billa screw which rotates around a fixed threaded rod 50 secured to the sliding branches of the brackets. The cross 19 which is advantageously made of glass or carbon fiber, is coated on its inner sliding part with a Teflon coating. A low-cost construction variant of this device consists in motorizing the two sliding axes of the cross 19 by means of direct current motors and samarium-cobalt magnets. In this case, the transmission of the rotational movement of the motor is effected by means of pinions and a toothed belt coupled to a conventional ball screw.

 The suction cups 22 have at their lower part a sensor 29 (see FIG. 3) which detects the proximity of the window 49. In their resting state, these suction cups have a certain curve which decreases when they are in contact with the window, this which makes them thinner. The sensor 29 has two thresholds and it uses the elastic curve effect of the suction cup to trigger the second threshold: the first threshold is the detection of the surface by tactile effect, and the second corresponds to the change in the shape of the curve which is detected by a microswitch or any other proximity detector, the shape of the curve being a function of the effectiveness of the adhesion of the suction cup. As a sensor, it is possible to use a "robot skin" which is in fact an elastomer which becomes conductive in the presence of a pressure on its surface. One can also use probes with micro-contactors or magnets approaching Hall effect sensors according to the deformation of the suction cup. The suction vacuum of the suction cup, for its part, is created from compressed air by a venturi device 48 mounted on each suction cup.

 A light structure in plastic material 29 (see FIGS. 1 and 4) is fixed between the two jacks 23 forming the vertical axis 211 of the attachment bracket 21. This structure can be in the form of a dome or a shell or it can present any other suitable form to serve as housing for the robot electronics and the electric power amplifiers of its motors. To ensure good stability for the robot, this electronics 29 and these power amplifiers 30 which weigh a few kilograms must be located in this shell 29 as shown in FIG. 6. In addition, the power amplifiers can be housed in the ballast 18 of the connecting cable 16 as shown in Figure 6 in cases where the cable 16 is very long.

 The robot is equipped with window squeegees 24 (see FIG. 1) which can be three in number and which are made integral with a hooking bracket 20 or 21 by means of one or two electromagnets 32 with plunger core which bring them into contact with the glass by means of cleaning. The cleaning tool itself, 24, is a wiper blade of the type used on motor vehicles which is fitted with a lip 26 made of neoprene or "silastene". A plastic pipe 25 (see FIG. 8) pierced in several places releases the window washing liquid when the solenoid valve which conveys the liquid coming from the connection cable in the pipe 25 is in the open position.

The operating mode of this device is as follows
The robot moves step by step, laterally to the right or to the left, or vertically up or down; it can also progress on inclined surfaces or even on a horizontal support.

 If the robot has to take a step to the right, for example (Figures 9 to 14), it performs the following phases 1. It is first initialized in the position of Figures 9 and 10, where the brackets 20 and 21 are in the grouped position, the jacks of the bracket 21 being fully retracted and the robot being in abutment on the gripping bracket without jacks 20.

2. According to FIGS. 11 and 12, the robot goes into an elongated configuration along its horizontal axis while resting on the gripping bracket without jacks 20, while the axial drift correction is integrated into this translational movement, as well as this will be explained below.

3. The robot simultaneously extends the three jacks 23.

As soon as the suction cup sensor 29 detects the surface to be cleaned, the corresponding jack is immobilized and the vacuum is established in the suction cup in contact with the window. The same sequence is repeated for each cylinder. Due to the deformation of the structure and the engaged suction cups, the suction cups of the jacks 23 do not touch the surface of the glass at the same time. As soon as all the cylinders have found contact with the glass via the suction cups and all these are activated, the computer software checks that the vacuum is established on all the suction cups of the cylinder bracket 21. If only one of the latter is not in sufficient vacuum, the robot continues its movement. If, on the contrary, more than one suction cup is not in sufficient vacuum, the software calls a subprogram which makes it move back the robot to its previous position and initiates a repositioning procedure which will be described later. The robot is then in the position shown in FIGS. 13 and 14, all the suction cups then being in adhesion on the support.

4. The robot deactivates the suction cups of the bracket without cylinders 20 and extends the cylinders 23 to the maximum, the robot being in the position of FIGS. 15 and 16.

5. The robot remains supported on the jack angle 21 and moves the other angle 20 against the first. It is then in the position of FIGS. 17 and 18.

6. The robot performs the correction of drift along the vertical axis, as will be described later, and, using the jacks 23, it puts the suction cups of the bracket 20 in contact with the glass. All cylinders are activated at the same time. As soon as a group of suction cups touches the window, the movement of the corresponding cylinder is stopped and the group of suction cups is placed under vacuum. As in phase 3, the software checks the adhesion condition when all the suction cup groups are in depression. If more than one of them is not sufficiently under vacuum, the software calls a subroutine to reposition the robot correctly.

7. As soon as the suction cups of the angle bracket without cylinders are correctly pressed against the glass, the suction cups of the other angle bracket are deactivated and the cylinders fully retracted. The robot is then in its initial position of FIG. 9 and it has taken a step.

 To move to the left, the robot follows the same process, but the translation from one square to the other takes place to the left. Similarly, to go up or down, the walking principle is similar, but the robot uses the other degree of freedom of the brackets 20 and 21, as seen in Figure 19.

 The mechanical structure of the robot and its progression process allow it to pass over the joinery profiles which are generally made of aluminum. Indeed, its software includes a subroutine which tests at each step the grip and the adhesion of the suction cups 22 via the sensors 29, as has been said above, so that it refuses to progress on an openwork surface such as a ventilation louver or a hollow joint. To ensure the safe operation of the robot, its software only releases one of the suction cup groups if at least half of all the suction cups are in adhesion.

 For cleaning work, positioning accuracy of the order of two to three millimeters is imperative. One of the original arrangements of the robot according to the present invention allows it to reposition itself at each step by scanning the facade of the building with a repositioning sensor 29 ′ (FIG. 1). Each hollow due to a joint or each carpentry profile is considered by the robot software as a reference point on which the latter readjust its navigation.

 Between two landmarks, the robot bases its navigation on the addition of displacement vectors. This principle is known and it is called "dead reckoning". The robot admits a navigation error at each step, these errors being due to the imprecision of the sensors and control devices, to the mechanical play of the robot structure, to the slight sliding of the suction cups and to the compression of the latter. To avoid equipping the robot with expensive navigation sensors capable of giving it information on its drift, an incremental repositioning of the trajectory is provided using an original device which includes the 2g repositioning sensor placed on the lightest mounting bracket.

During the robot learning phase, the robot keeps in memory the references specified above. The installation software calculates the rotational drift of the robot and its drift along the two horizontal and vertical axes X and Y from the indications provided by the sensor 29t which can be an ultrasonic sensor, a modulated infrared proximity sensor , a tac-tile sensor or a video camera
The result of this drift calculation is of course filtered and integrated as a function of the preceding displacements. This type of operation being well known, it will not be described below in detail; for example, it leads to a rotation of - 20; -a displacement in width (axis X) of - 1 mm and a displacement in height (axis Y) of + 2 mm, which is integrated in the following way with the movements of the robot
At each step, there is an instant when the two brackets 20 and 21 of the robot are glued to the glass. To execute a correction in rotation, we deactivate the suction cup groups of the bracket without cylinders 20, with the exception of group C at the top left (see Figure 15) ~ which will serve as a pivot.

Using the control members of the sliding cross 19, the robot goes up or down one or two steps, or two or four millimeters, which causes a slight rotation of the square concerned. To facilitate this maneuver, the jack located at the top left of the bracket 21 slightly loosens this part of the robot structure, which prevents the displaced suction cups from rubbing against the glass during movement.

 Once this movement has been made, the suction cups of the square without cylinders 20 are reactivated and the robot can continue on its way. Naturally, this correction principle does not work if all the suction cups of the square without jacks 20 are deactivated.

 This principle of correction in rotation allows the robot according to the invention to move along its trajectory as if it had an additional degree of freedom, without it being obliged to carry the weight of a structure, a corresponding control device and power control. Regarding the corrections along the X and Y axes, they are automatically combined with the movements of the robot along these X and Y axes.

 When the robot must move on a large geodesic dome, it is useful to interpose a pivot 30 (see Figure 7) between the cylinder 23 located at the top left of the device and the slide of the bracket 21. This articulation is angularly moved by a control mechanism 31 composed of a motor which rotates a threaded rod 31 'screwed into a connecting rod 31 "secured to the bracket 21, the motor being for its part secured to the other branch of this This arrangement makes it possible to give more amplitude to the corrections in rotation of the robot and the corresponding device 30, 31, 31 31 "weighs approximately 600 grams, which is lighter than a robotic control apparatus of conventional type corresponding to an additional degree of freedom. On the other hand, when the robot moves on a geode, part of its weight is in direct support on the dome and, consequently, its suction cups do not work only in tangential force compared to the surface, since they also admit a larger perpendicular component. This fact keeps the same safety factor, even if the robot is slightly heavier.

 Finally, note that the cleaning process takes place at the same time as the robot is running. For cleaning combined with moving to the right for example, the sequence No. 4 of the process on page 12 above includes cleaning, however this sequence is doubled if the building has not been washed for more than four weeks . Note that the arrangement of the wipers 24 (see Figure 1) at the top, right and left of the robot allows it to clean and wash behind it when it moves horizontally or down, which prevents it from marking the window with the imprint of its suction cups. Its morphology also allows it to access the edges of the windows in a perfect way, even when the building forms a corner return.

 The electronic architecture of the robot according to the invention is divided into two parts, the first being located in the control and storage station (Figure 5) and the second being in the body of the robot itself (Figure 6) ).

 The control station comprises an IBM-PC computer or the like with a main printed circuit 7 to which a bubble memory card 8 or another type of permanent memory, PROM or EPROM for example, is connected, a capacity of 300 Kbits being sufficient. A display screen card 10 is also connected to the main card 7, as well as an input / output card 11 for the functions of the robot control station. The latter is connected to input / output interfaces.

 The two-speed motor 33 of the winch for winding the connecting cable can operate in both directions and it has a power cut brake which stops the cable in question in the event of a lack of current, which allows it to serve as a safety cable for the robot. The input / output card is connected to a winch rotation encoder which thus provides the absolute value of the cable length unwound. This card 11 is also connected to the motorization of the door of the storage station, for the limit switches of this door, to the window washing liquid reservoir, to the air compressor and to the electrical relay of the anemometer, as well as '' at the compressed air pressure switch. All these devices have been described above with reference to FIG. 1, so that they will not be repeated here.

 A modem card 35 is connected to the main card 7 to allow communication by telephone between the maintenance center and the robot control station.

Thus, when the latter detects a problem during its self-diagnosis, the code corresponding to this fault and its degree of urgency are transmitted to the maintenance center for intervention.

 Another important card is connected to the main card 7: it is another input / output card for the robot itself, 12, which is coupled to a serializer / deserializer which transforms the signals from the input / output card. serial in parallel and vice versa and which is connected to a transmitter / receiver for optical fibers transforming electrical signals into optical signals and vice versa. Such systems are well known and will not be described here in more detail.

 In the robot itself (see FIG. 6), the two optical fibers 36 are connected to an opto-electronic card 37 which converts the optical signals into electrical signals and which distributes the latter over an electronic collector or "bus" 29 serving of support for electronic cards, this "bus" comprising the addressing signals, the input / output signals and the control signals. An input / output card and a microprocessor card are connected to this "bus", while the input / output card controls the solenoid valves of the suction cups, the sensors of these suction cups, the electromagnets of the window squeegees and the spray solenoid valves washing liquid. The robot's microprocessor card is connected to the interface cards corresponding to the robotic axes.

 In general, one interface card per axis is used, this card entering the signals of the axis encoder which is an incremental encoder or a resolution encoder, as well as the axis limit switches. The axis interface card generates control of the corresponding axis motor, this control being amplified by a power card which is connected to the motor. The five axes in question are the three cylinders and the displacements of the attachment brackets of the robot, and each of them is wired according to the diagram described above.

 The robot motors can be direct or alternating current electric motors, pneumatic motors or linear motors but the most recommended type for the present application is the motor without collector which requires less maintenance, which is more resistant to bad weather and which develops more power per unit of weight.

 The programming of the robot according to the invention is done by means of well-known learning techniques.

The structure of the robot software includes macro tasks for basic functions such as advancing a standard length step, cleaning in two passes with right washing, etc. It corresponds to the following operating modes 1. Direct learning in real time with the control unit. The robot led by the programmer physically describes its trajectory on the facade of the building and, at the same time, this program is stored in the memories of the computer.

2. Learning without robot in delayed time. The programmer enters the data from the facade of the building into a computer located in his design office. Depending on the data, the computer optimizes the trajectory of the robot and it converts this trajectory into a succession of macro-tasks. The latter are then transmitted to the robot computer by the modem 35 (FIG. 5) or directly stored on the circuits of the memory card 8.

3. Remote control. The programmer directly controls the robot, in real time, with the control unit, but no macro-task is stored in memory.

4. "Execution" mode. The robot executes macro-tasks stored in its memory without operator.

 It will also be noted that, when the length of the connecting cable 16 (FIG. 1) is maximum, that is to say around 70 meters, and therefore when its weight is maximum, it is advantageous to mechanically couple the ballast 18 (FIGS. 1 and 2) and the robot proper to obtain a damping effect of the movements of the cable 16. This mechanical coupling is carried out simply using fiberglass rods attached to the cable between the ballast and the robot. These rods form flexible springs and they dampen movements between the robot and its connecting cable. In addition, the ballast 18 can be secured to a series of emergency suction cups which are activated automatically when the robot software detects a fault.

 As far as facade crossing devices are concerned, the ideal type of facade for the robot of the present invention is flat or with a small curvature, the facade should not have carpentry profiles of more than about 80 mm in height and more than approximately 300 mm in width. These usage constraints are widened by the use of facade crossing devices.

 A first embodiment of such devices is designed to pass over the ventilation grilles or any free opening of the facade. This device consists of shaped crossing bearings corresponding to the steps of the robot and it is made of a non-porous material such as stainless steel or glass. These bearings are interconnected by rigid metal, plastic or glass spacers. The robot of the present invention is designed to be able to pass from the regular facade to this device without modifying the programming or the geometry of the gripping brackets or the structure of the robot.

 A second embodiment of the crossing device is designed, not only to establish a passage to the same nude of the surface of the building, but also to change the nude. This device is based on the same principle as the first, but, instead of being on the same facade, the crossing levels are offset in bare without ever exceeding the limits of obstacle that can be crossed by the robot. These staggered landings are the equivalent of a staircase to approach or move away from the facade of the building.

 The crossing bearings of the first and second device can be completed or replaced by L-shaped hooks. In this case, these hooks must correspond to holes made on the supports 46 of the suction cups (Figure 3). These hooks are made of a magnetic material so that they can be detected by the suction cup sensors.

 Also, in the same way, it is possible to provide link bridges allowing the robot to pass from one building to another.

 Finally, the robot can be optionally equipped with a video camera and the computer with an automatic shape recognition device. The camera must be secured to the gripping bracket without cylinders 20 and the video signal must be transmitted over a second optical frequency from one of the two optical fibers of the connecting cable. With such equipment, the robot can automatically inspect the facade joints and detect through windows the presence of intruders, the presence of light or even excessive temperatures, which saves energy.

The computer 7 (Figure 5) mounted on the roof of the building is optionally equipped with an image processing of the robot's video camera to detect any difference between a prerecorded image and the image of the same scene seen by the robot. These shape recognition methods are well known and many applications can be realized by this optional equipment for the guarding and inspection of buildings.

Claims (13)

- CLAIMS 1. Robot for the maintenance of buildings, of the type comprising a connecting cable which connects it to a control and storage station, characterized in that it comprises a sliding cross (19) in which can move, at a right angle and in a controlled manner, a branch of a first L-shaped bracket (20) and a branch of a second L-shaped bracket (21), said brackets, the planes of which are substantially parallel, being provided with gripping members (22); means for activating and deactivating said gripping members at will; means (23) for moving the gripping members (22) of one (21) of said brackets perpendicular to the plane of the latter; and means integral with said brackets (20, 21) for cleaning by spraying and scraping the surfaces to be maintained. 2. Robot according to claim 1, characterized in that, when it is in the vertical operating position, said first bracket (20) has a horizontal branch which passes through said sliding cross (19), and, at a end of this branch, a vertical branch extending downward, while said second bracket (21) has a vertical branch which passes through said sliding cross (19) and, at the upper end of this branch, a branch horizontal extending in the opposite direction to the vertical branch of said first bracket (20). 3. Robot according to any one of claims 1 and 2, characterized in that said gripping members are suction cups (22) arranged, preferably in groups of two, in the vicinity of the apex and the two ends of the angle right formed by said L-shaped brackets (20, 21).  Robot according to claim 3, characterized in that said suction cups are provided with two threshold sensors. 5. Robot according to any one of claims 1 to 4, characterized in that said means for moving the gripping members (22) of one of said brackets (20, 21) perpendicular to the plane of the latter are jacks (23) integral with said bracket (21) and perpendicular to its plane comprising a motor (38) which rotates a threaded rod (42) screwed into a finger (44) of polygonal section, the latter sliding in a passage of corresponding shape which prevents it from rotating and carrying at least one gripping member (22) at its end opposite the threaded rod (42). 6. Robot according to any one of claims 1 to 5, characterized in that said means for cleaning by sprinkling and scraping of the surfaces to be maintained include elastic scraper (26) associated with spray bars (25) and integral with said brackets (20, 21), said wipers preferably being arranged, one horizontally and two others vertically, in the vertical operating position of the robot, at the end of the assembly formed by said brackets (20, 21) . 7. Robot according to any one of claims 1 to 6, characterized in that the bracket (21) whose gripping members are not provided with means for moving them perpendicularly to the plane of the bracket comprises a sensor repositioning (29). 8. Robot according to any one of claims i to 7, characterized in that the two branches of one (21) of said attachment brackets are articulated one on the other, the angle formed between them can be set to a predetermined value using control means (31). 9. Robot according to any one of claims 1 to 8, characterized in that an inclinometer (17) is mounted on said connecting cable (16), a short distance from the robot, to control the unwinding or the winding of said cable (16) when it is no longer horizontal. 10. Robot according to any one of claims 1 to 9, characterized in that its connection cable (16) is provided with a ballast (18) that contains the electronic interface of the robot and / or the power amplifiers robot control devices and / or a washing liquid buffer tank and / or a compressed air buffer tank, said ballast (18) being coated with a compressible shock-absorbing envelope. 11. Robot according to any one of claims 1 to 10, characterized in that said control and storage station comprises in particular a cabinet (1), a winch (3) for winding and unwinding said connecting cable (16), a power supply (4), an air compressor (5), a control computer (6), a mixing tank (14) and a dosing pump for the cleaning product and an anemometer (15). 12. Robot according to any one of claims 1 to 11, characterized in that it comprises a crossing device provided in particular with studs integral with said attachment brackets (20, 21). 13. Robot according to any one of claims 1 to 12, characterized in that it comprises means for correcting the drift of its trajectory during its progression over the surface to be maintained. 14. Robot according to any one of claims 1 to 13, characterized in that it is equipped with an optional video camera.