Robotic cleaning head

(54) Title: ROBOTIC CLEANING HEAD (30) Unionist Priority: 22/01/2007 ep 07100907.0 (73) Holder (s): koninklijke Philips Electronics NV

(72) Inventor (s): Alexander P. Splinter (74) Attorney (s): Momsen, Leonardos & Cia.

(86) International Order: pct ib2008050140 of 16/01/2008 (87) International Publication: wo 2008 / 090490of 07/31/2008 (57) Abstract: ROBOTIC CLEANING HEAD. A robotic cleaning head (1; 101) for use as part of a stand-alone vacuum cleaning system (2) including a container unit (3) and a hose assembly (4; 104) connecting the cleaning head (1 101) to the container unit (3). The cleaning head (3) has a chassis (5; 105), a drive system (6; 18; 27), a vacuum cleaning nozzle (8; 108) and a duct (9; 109). The duct (9; 109) communicates with an air passage bounded by the cleaning nozzle (8; 108). It is suspended swiveling on a pivot axis (10; 110) and includes an entrance (11; 111) provided on top of the mentioned chassis (5; 105), and an elbow section (12; 112) downstream of the entrance (11 ; 111), and the duct (9; 109) is suspended and shaped so that a line of action (15; 115) of a pulling force (20; 120) exerted by the hose assembly (4; 104) on the chassis (5; 105), through the conduit (9; 109) to which the hose assembly (4; 104) is connected, extends spaced below an end downstream of the elbow section (12; 112).

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ΡΙ0806788-0 “ROBOTIC CLEANING HEAD”

FIELD OF THE INVENTION

The invention relates to a robotic cleaning head for use as part of an autonomous vacuum cleaning system further including a container unit and a hose assembly connecting the cleaning head to the container unit.

BACKGROUND OF THE INVENTION

Such a robotic cleaning head is disclosed in European patent application 1 360 922. The container unit maintains a fan, a motor to drive the fan, dust filters and a dust collection chamber. Therefore, the cleaning head can have relatively small dimensions, which is advantageous for agility and to reach areas overloaded with dust, for example, under furniture and in corners. For the cleaning head maneuverability, it is advantageous that the hose connects to a cleaning head duct that is swivelable on a pivot axis and that the duct includes an elbow section downstream of a duct inlet. extending coaxially with the pivot axis.

In operation, the hose assembly exerts force on both the cleaning head and the container unit due to friction on the floor and reaction forces in response to flexing the hose. These forces impact the cleaning head's maneuverability. For example, when the cleaning head moves forward it drags together at least an adjacent portion of the hose and the forces exerted by the hose are most often oriented at an angle to the intended direction of travel of a cleaning head and affects the effective direction of travel of the cleaning head. This results in less precise control over the travel path and therefore less effective cleaning results and / or slower progress on the floor surface. Furthermore, deviations from the route increase the risk of colliding with objects.

SUMMARY OF THE INVENTION r

It is an object of the invention to provide a cleaning head to which the maneuverability is less sensitive to forces exerted on it by the hose to which it is connected.

In accordance with the present invention, this object is achieved by providing a robotic cleaning head according to claim 1.

Because the conduit is suspended and shaped so that, in operating condition, a line of action of a pulling force exerted by the hose assembly on the chassis through the conduit to which the hose assembly is connected, extends below one end downstream of the elbow section, the moment of inclination resulting from the force exerted on the cleaning head by the hose and the frictional forces between the floor and the cleaning head are relatively small. Consequently, the moment of inclination exerted on the cleaning head under certain forces exerted by the hose is substantially reduced. As a result, there is less reduction in contact pressure between the drive system and the floor on one side of the steering system. Such a reduction in the contact pressure between the drive system and the floor on one side of the drive system allows the drive system to slide more easily over the floor on that side, thereby negatively affecting steering accuracy.

The conduit may include a boom section extending from the elbow section radially to the pivot axis and an end section downstream of the boom section and at least partly extending horizontally out of the chassis and system. drive and down from the boom section, so that when in operating condition, a lower portion of the outlet end portion is at a level below a higher portion of at least the chassis, the drive system or the nozzle. Through these features, lowering the line of action along which the pulling forces exerted by the hose assembly are transferred to the chassis is achieved in a simple construction manner. Furthermore, because of the lowered position of the outlet end of the duct to which the hose assembly is to be connected, when in operation, only a relatively short portion of the hose assembly extends from the floor to the duct, so that relatively little weight of the hose assembly is carried by the duct. Consequently, the contribution of the weight of the hose assembly portion carried by the duct to any tilting moment causing load relief on the wheels on the side of the cleaning head facing away from the duct is kept relatively small.

The duct is preferably a substantially rigid structure, so that, in operation, the outlet end is kept at a relatively constant level close to the ground regardless of the loads to which it is subjected in practice.

If the elbow section is pivotally suspended from the chassis on a rotating axis perpendicular to the pivot axis and extending spaced below the downstream end of the elbow section, while the conduit is in the range in which it is freely movable, apart from a slight moment due to the frictional resistance, no moment on the rotating axis can be transferred from the duct to the cleaning head. Consequently, the line of action along which a pulling force exerted by the hose assembly is transferred to the cleaning head will intersect the rotating axis spaced below the downstream end of the elbow section.

The pivot axis can be a virtual pivot axis defined through a connection link from the elbow section to the chassis, such as a joint including at least two links of at least one four-link joint including the elbow section and the chassis. If, moreover, for at least one link position, the rotating axis extends below the chassis, a particularly effective reduction or even elimination of the tilting moment is achieved, because the action line of the feasible reaction forces between the ground and the cleaning head extends along the floor, ie very closely along or even intercepting the rotating axis that determines the line of action along which the traction force exerted by the hose assembly is transferred to the cleaning head. Furthermore, by providing a support member under the outlet end portion of the conduit, to support the conduit in relation to the floor surface, the rotational capacity in operating the conduit in relation to the chassis can be limited. This is advantageous to maintain the duct from reaching a limit of its range of rotation capacity on the rotating axis, thereby preventing the transfer of any significant moment on the rotating axis of the duct to the chassis.

Providing that the pivot axis extends closely adjacent to an axis of rotation on which the chassis rotates when changing its direction of travel on the floor surface, it is achieved that the forces exerted on the cleaning head through the set of hose have little or no influence on the direction of action of the cleaning head.

A particularly important improvement in the steering capacity can be achieved in a cleaning head in which the drive system includes at least two rotating members to move a cleaning head in a driving direction when circulating it in unison, at least, two rotating members being spaced apart transversely to the driving direction to the right and to the left of a central plane of the chassis oriented in the driving direction, the drive system is still controllable to drive the rotating members at different selectable speeds of circulation to direct the cleaning head. More in particular this is then balanced so that the wheels on one side are unloaded and the opposite wheels are loaded and a difference in rotation speeds between the wheels on the opposite side results in sliding of the unloaded wheels and none or just a limited drag steering effect.

If the inlet end of the duct is facing up and the swivel duct connects from under a portion of the air duct communicating with the nozzle, the swivel duct can rotationally connect to the non-rotating air duct if communicating with the nozzle at a low level in order to keep the moments in a vertical plane transferred through the low swivel connection. Furthermore, the elbow section can be swiveled to the chassis in a simple way by means of an articulation positioned between the conduit and the chassis.

Additional aspects, effects and details of the invention are set out in the detailed description with reference to examples of which some are shown in the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is the perspective view of an autonomous vacuum cleaning system comprising a cleaning head according to the invention;

Fig. 2 is a top view of a cleaning head of Fig. 1;

Fig. 3 is a front view of a cleaning head of Fig. 1; and

Fig. 4 is a side view of an alternative embodiment of a cleaning head according to the invention.

DETAILED DESCRIPTION OF THE MODALITIES

In Fig. 1, a stand-alone vacuum cleaning system 2 composed of a container unit 3, a robotic cleaning head 1 and a hose assembly 4 interconnecting the container unit 3 and the robotic cleaning head 1 is shown.

According to a present example, container unit 3 is self-propelled and self-directed and includes a drive system, a container, an energy source and an electric fan to generate suction power. The drive system for the container unit 3 has two drive wheels located in the rear corners (only one is visible in the figure) and two casters located near the hose connection in front of the container unit (only one is visible in the figure) .

Cleaning head 1 (shown in more detail in Figs. 2 and 3) is self-propelled and self-directed by means of a drive system including a control system 6, a drive assembly 27 and wheels 18. The assembly of vacuum hose 4 communicates with a cleaning nozzle 8 of the cleaning head 1 so that the vacuum generated by the container unit is made available at an inlet of the nozzle 8. The cleaning head 1 is more agile than the container unit 3 and is able to pass under most objects, such as furniture or radiators. The container unit 3 is further equipped with sensors to provide information about the surroundings and a control unit to use the information provided by the sensors to plan routes for the container 3 and the cleaning head 1 and to conduct the container 3 and the cleaning head 1 along these routes. In operation, the cleaning head 1 is more mobile than the container unit 3, which is controlled to be within reach of the cleaning head 1 which moves on the floor according to a vacuum cleaning pattern. The range is determined by the length and mobility of the hose assembly 4. It is also possible to provide that only the cleaning head 1 is equipped with a drive system and tows the container unit 3 through the hose assembly 4.

The power source for the autonomous vacuum cleaning system can be supplied in the form of rechargeable batteries, fuel cells, or other autonomous sources of power, or through a connection to a domestic power network.

A drive assembly 27 of the cleaning head 1 includes a motor (not shown) coupled to the wheels 18 via a transmission, clutches and brakes to selectively move and brake the wheels 18 under control of the control system 6. The four wheels motors 18 of the cleaning head drive system 1 direct the movement of the cleaning head 1 in a driving direction (arrow 29) when operating to circulate in unison. The wheels 18 of the drive system are spaced apart transversely to the driving direction to the right and to the left of a central plane 28 of the chassis 5 oriented in the driving direction 29 of the chassis 5. The drive assembly 27 is controllable to drive the wheels 18 at different speeds to direct the cleaning head 1. Changing the driving direction 29 can be achieved by turning the wheels 18 on the placed sides of the central plane 28 of the chassis 5 at different speeds, temporarily blocking the wheels on one side or even operating the wheels on the opposite sides in opposite directions of rotation.

In place of or in addition to the wheels, the drive system may also include other rotating members, such as traction tracks. Furthermore, instead of all rotating members, only some of the rotating members can be triggered and / or some can be directed.

A vacuum cleaning nozzle 8 is mounted on a front end of the chassis 5 of the cleaning head 1. The nozzle 8 delimits an air passage 30 extending through it. A conduit 9 communicates with a cleaning nozzle 8 through an air duct 31 to conduct air received through the air passage 30 to the hose assembly 4. The conduit 9 is suspended swiveling on a generally vertical pivot axis 10 to accommodate changes in the driving direction 29 of the cleaning head 1 and for changes in position in relation to the cleaning head 1 in relation to the container unit 3 as it goes and comes while vacuum cleaning a surface of the floor. The dashed and dotted lines in Fig. 2 illustrate a different orientation of the chassis 5 and the nozzle 8 in relation to the hose assembly 4 reachable by changing the driving direction 29.

The hose assembly 4 may include wires to supply power to the cleaning head 1 and for communication between the cleaning head and the container unit 3.

Conduit 9 has an inlet 11 provided at the top of the chassis 5, a section of the elbow 12 downstream of the inlet 11, a boom section 13 extending radially from the elbow section 12 to an outlet end section 14 downstream of the section boom 13. Preferably, the input is coaxial with the pivot axis 10.

Since the conduit 9 to which the hose assembly 4 is connected is rotatable on a pivot axis 10, it is prevented that the hose assembly 4 exerts substantial torque on the pivot axis 10 of the cleaning head 1 and thereby , influence the route path.

Furthermore, in the present example, conduit 9 projects horizontally beyond the base of the chassis 5 and drive system 6, 18, and 27 in any orientation of conduit 9. This ensures that conduit 9 and hose assembly 4 can be able to rotate with respect to chassis 5 and drive system 6, 18, 27 without forcing hose assembly 4 or duct 9 to collide with chassis 5 or wheels 18 or other parts of the drive system. In the present example, the conduit 9 also projects horizontally beyond the cleaning nozzle 8 when rotated in an orientation extending over the cleaning nozzle 8, so that the conduit can also rotate in the orientations in which they extend towards the front direction on the cleaning nozzle 8 without forcing the hose assembly 4 to hit the cleaning nozzle.

The pivot axis 10 is oriented substantially perpendicular to the floor surface 7 supporting the cleaning head 1 (ie substantially vertically when in operation), so that the duct 9 rotates in a substantially horizontal plane and gravity does not force the duct 9 to rotate to a lower position. Furthermore, the pivot axis 10 extends closely adjacent to an axis of rotation of the rotational component of the movement when the chassis 5 changes its direction of travel on the surface of the floor 7 and is located between the axes of rotation of the wheels 18 Therefore, the forces exerted on the cleaning head 1 by the hose assembly 4 have little or no influence on the direction of operation of the cleaning head 1.

As best seen in Fig. 3, the conduit 9 is suspended and shaped so that, in the operating condition, an action line 15 of the pulling force 20 exerted by the hose assembly 4 on the cleaning head 1 through its conduit 9, extends spaced below an end downstream of the elbow section 12 of the conduit 9.

The pulling force 20 exerted on the cleaning head 1 causes a reaction force in the opposite direction in the form of friction between the cleaning head 1 and the floor. The line of action of this frictional force is at a ground level. Consequently, the pulling force 20 and the frictional force result in a moment of inclination exerted on the cleaning head 1. Because the action line 15 along which the pulling force 20 in the flexible hose assembly 4 is transferred to the cleaning head 1, extends spaced below an end downstream of the elbow section 12 of the conduit 9, this line extends along the positions where the cleaning head 1 contacts the floor 7 at a lower level than the downstream end of the elbow section 12 along which the line of action would extend if the hose assembly were connected directly to the elbow section 12, as is usual with such rotatable vacuum cleaning hose connections. Due to the lower location of the action line 15, the moment of inclination forced by the pulling force 20 and the frictional forces in reaction to it, is substantially reduced. In turn, this reduced tilt moment results in a reduction of the load relief of the wheels 18 on the side of the cleaning head facing unlike the side of the cleaning head 1 to which the duct 9 is forced by that tilt moment . Consequently, the adverse effect of such load relief on the steering capacity of the cleaning head 1 is reduced.

The inclination moment exerted on the cleaning head 1 is especially disadvantageous when the main orientation of the pulling force 20 is directed transversely to the driving direction, as shown in Fig. 3. The different amounts of forces on the opposite side sides of the cleaning head 1 negatively influence the drive system's ability to guide the cleaning head 1 along a predefined path, especially on delicate floor types such as leather carpet. high. This is of particular importance if, as in the present example, directing to another driving direction is carried out selectively by forcing the wheels 18 'on one side of the cleaning head 1 to rotate at a different speed than the wheels 18 ”On the other side of the cleaning head 1. When, for example, the 18 ”wheels on one side are unloaded and the wheels 18 'on the opposite side are loaded, a difference in rotation speeds between the wheels on opposite side sides would tend to result in the sliding of the unloaded wheels 18” and none or only a limited effect on driving.

A similar disadvantageous effect of load relief on one side and load on the opposite side due to an inclination moment would also occur if other rotating members than the wheels, such as traction caterpillars, were provided.

However, if steering is also to be performed by changing the orientation of steering wheels or other rotating members, loading and side load relief negatively affect steering accuracy if obstacles such as a door step, carpet edge or a cord energy positioned on the floor needs to be passed. Furthermore, in particular in such cleaning, loading and unloading heads forward or backward, forcing the front to be loaded and the rear to be unloaded or vice versa, negatively affects the steering accuracy, because the rear or front of the cleaning head can then slide sideways relatively easily.

In the example shown in Fig. 3, conduit 9 includes an outlet end section 14 downstream of boom section 13 and at least partly extending horizontally out of chassis 5 and drive system 6, 18, 27 and to below boom section 13. When in operating condition, a lower portion of the outlet end portion 14 is at a level below the upper portions of chassis 5, drive system 6, 18, 27 and the cleaning 8. Therefore, lowering of the action line 15 along which the pulling forces 20 in the hose assembly 4 are transferred in the cleaning head 1 is achieved in a simple construction manner.

Furthermore, since the hose assembly 4 connects to the conduit 9 in a manner close to the floor 7, only a relatively short portion of the hose assembly 4 extends from the floor 7 to the conduit 9, so that the relatively light weight of the hose assembly 4 is carried through conduit 9. Consequently, the contribution of the weight of the hose assembly to the (unwanted) tilting moment by relieving the wheels 18 on the side of the cleaning head 1 facing away from the conduit 9, forced by the weight of the portion of the hose assembly carried by the conduit 9 , is relatively small.

The conduit 9 is a relatively rigid structure, for example substantially more rigid than the vacuum cleaning hose 4, so that, in operation, the outlet end 14 is kept at a relatively constant level above the floor 7 regardless of loads to which it is subjected in practice. Because, furthermore, the conduit 9 is rotatable on the pivot axis 10 only, an opposite moment contrary to the moment of inclination, which opposite moment is exerted by the outlet end section 14 in the boom section 13 of the conduit 9 when the traction force in the hose assembly is transferred through the outlet end section 14, it is effectively transferred from conduit 9 to chassis 5, thereby forcing the lowest effective position of the action line 15.

In Fig. 4, an alternative example of the cleaning head 101 according to the invention is shown, in which the elbow section 112 is pivotally suspended in relation to the chassis 105 on the rotary axis 116 generally perpendicular to the pivot axis 110 and extending spaced below the downstream end of the elbow section 112 in the direction transverse to the line of action 115. A boom section 113 extends radially in relation to the pivot axis 110 and transversely to the rotary axis 116 between the elbow section 112 and a downward flow from the outlet end section 114 of the boom section 113.

Because, in operation, conduit 109 is rotatable in relation to the chassis on the rotating axis 116 which is generally oriented horizontally and transversely to the line of action 115 of the forces exerted by the hose assembly 104 on the chassis 105, while conduit 9 is in the range in which it is freely movable, apart from a slight moment due to the frictional resistance, no moment on the rotary axis 116 can be transferred from the duct 109 to the cleaning head 101. Consequently, the line of action 115 along which the pulling force 120 exerted by a hose assembly 104 is transferred to the cleaning head 101 will intercept the rotary axis 116 located below the downstream end of the elbow section 112.

Preferably, the suspension of the duct 109 is connected to it and coupled to the chassis 105 so that the rotary axis 116 can rotate together with the duct 109, so that the rotary axis 116 remains substantially perpendicular to the line of action 115 if the duct 109 is rotated.

Furthermore, due to the rotation capacity of the duct 109, also the loaded weight of the portion of the hose assembly 104 that is free from the floor 107 will not result in a moment of inclination exerted on the chassis 105.

According to the present example, the rotary axis 116 is a virtual rotary axis defined by structure 117 connecting the elbow section 112 to the chassis 105. The virtual rotary axis 116 extends below the chassis 105 and coincides with the floor surface 107, so that the line of action 115 along which traction forces exerted by the hose assembly are transferred to the cleaning head 101 extends along the floor 107. Since the line of action of the frictional reaction forces between the floor 107 and the cleaning head 1 also extends along the floor 107, no moment of significant inclination is caused. It is preferred that the rotary axis is closer to the floor than 2 cm and more preferably closer to the floor than 1 cm.

In the present example, the structure connecting the elbow section 112 to the chassis 105 including two pairs 135, 136 of links of four connecting bars, the other pairs of bars being formed by the elbow section 112 and the chassis 105. Also other links , such as a molded sliding dome mechanism or ball bearing are conceivable.

For the outlet end portion 114 of the duct 109, the caster wheel 124 to support the duct 109 in relation to the floor surface 107 is mounted, minimizing friction between the duct 109 and the floor surface 107. The support provided by caster wheel 124 limits the rotation capacity in the operation of the duct 109 in relation to the chassis 105 and consequently the turning range of the structure 117. This is advantageous for maintaining the conduit 9 from reaching a limit of its range of rotation capacity on the rotating axis, thereby preventing the transfer of a moment on the rotating axis 116, from the conduit 109 to the chassis 105. Alternatively, instead of using the wheel 124, the support can also be provided in other forms, such as in the form of a slide, and the support can also be mounted next to the hose assembly, preferably close to the driver.

The inlet end 111 of the duct 109 faces upwards and the swivel duct 109 connects from under an air duct portion 125 communicating with the nozzle 108. This allows the swivel duct 109 to swivel to the duct non-rotatable air 125 communicating with the nozzle 108 at a low level in order to maintain moments in a vertical plane transferred through the low rotatable connection. Furthermore, this feature allows for a swiveling way to connect the elbow section 112 to the chassis 105 in a simple way by means of a joint 117 positioned between the duct 109 and the chassis 105. A flexible hose 126 interconnects to the air duct portion 125 to which conduit 109 is connected and to the nozzle 108 and provides a connection between the rotating air duct portion 125 and the stationary nozzle 108.

The robotic cleaning head for use as part of a stand-alone vacuum cleaning system includes a container unit and a hose assembly connecting the cleaning head to the container unit. The cleaning head has a chassis, a drive system, a vacuum cleaning nozzle and a duct. The duct communicates with an air passage bounded by the cleaning nozzle. It is suspended swiveling on a pivot axis and includes an inlet provided on top of the mentioned chassis, and an elbow section of the inlet downstream of the inlet, and the duct is suspended and shaped so that the line of action of the pulling force exerted through the hose assembly on the chassis, through the conduit to which the hose assembly is connected, extends spaced below the downstream end of the elbow section.

From the foregoing, it is clear that the qualified person, who within the operation of the invention as set out in the claims, also many variations other than the examples described above, are conceivable. For example, it is possible to use the cleaning head according to the invention in combination with a stationary container. Such a stationary container can be connected through a network of air ducts mounted on the wall, on the floor and / or on the ceiling with, for example, wall-mounted entrances in rooms within a building. The cleaning head can be connected via a relatively long vacuum cleaning hose to one of the wall-mounted inlets. Preferably, the hose is long enough to allow the cleaning head to autonomously clean, for example, at least a substantial part of an environment.

Furthermore, the conduit can be composed of several parts, for example, the elbow section, the boom section and the outlet section being separate tubular elements assembled to form the conduit. Alternatively, the conduit may, for example, be formed by flexing a single tube element.

Other variations to the disclosed modalities can be understood and affected by those skilled in the art in practicing the claimed invention, from a study of the designs, the disclosure, and the attached claims. In the claims, the word "comprising" and "characterized by the fact of understanding" do not exclude other elements or steps, and the indefinite article "one" or "one" does not exclude a large quantity. The mere fact that certain measures are cited in mutually different dependent claims does not indicate that the combination of these measures cannot be used to advantage. Any reference signs in the claims are not to be construed as limiting the scope.