BACKGROUND OF THE INVENTION

Pool cleaning robots are adapted for use for cleaning a pool while being connected to electrical power cables or to a hose of a suction system. The hose and/or power cable can get tangled and may temporarily limit the usage of the pool so therefore cable swiveling systems or battery operated cleaners are also used.

Pool cleaning robots are adapted for scanning or cleaning swimming pool surfaces such as floor and walls. Debris and dirt such as leaves float on the water surface and only after being soaked with water does the debris or dirt sink to the bottom surface and is then being able to be vacuumed by the pool cleaning robot. It is advantageous to have a pool cleaning robot that can perform both operations i.e.: skimming the surface and then sinking to the bottom to clean floor and wall surfaces.

Pool cleaning robots have difficulty in reaching certain areas of the pool such as stairs, corners or sidewall ledges that are difficult for the pool cleaning robot to reach or access and clean. This is because the basic vehicle configuration of pool cleaning robot s that may include wheels and/or tracks to traverse the floor and wall surfaces making it difficult or impossible to travel and effectively engage obstacles or reach all areas of the pool.

Once a filter of a pool-cleaning robot becomes clogged, the pool cleaning robot is manually taken out of the pool and its filter can be washed by a user of the pool cleaning robot.

Taking a pool-cleaning robot out of the pool is a time and effort consuming operation that is not very fond by the users. In many cases the users delay these manual operations or even skip them causing the pool cleaning robot to operate in a sub-optimal manner.

There is a growing need to provide autonomous robots that can effectively reach, brush and clean difficult to reach areas in the pool.

There is a growing need to provide autonomous robots that require a lesser amount of human intervention in their operation and in their maintenance.

SUMMARY OF THE INVENTION

According to an embodiment of the invention there may be provided a pool cleaning robot that may include a ballast tank for controlling a buoyancy of the submarine pool cleaner; at least one cleaning element for cleaning debris from an underwater surface of a pool while the pool cleaning robot hovers over the underwater surface; a propulsion module that is configured to propel the submersible pool cleaner; and a steering module that comprises a rudder and diving planes.

According to an embodiment of the invention there may be provided a pool cleaning robot and a movable base that are detachably coupled to each other; wherein the pool cleaning robot, may include a ballast tank for controlling a buoyancy of the submarine pool cleaner; at least one cleaning element for cleaning debris from an underwater surface of a pool while the pool cleaning robot hovers over the underwater surface; a propulsion module that may be configured to propel the submersible pool cleaner; and a steering module that may include a rudder and diving planes; wherein the movable base may be configured to support the pool cleaning robot while the movable base propagates underwater and to supply power to the pool cleaning robot. The movable base may also support the pool cleaning robot while being static. It is expected that when the pool cleaning robot hovers about a fixed location the movable base is static.

The underwater surface may be positioned above a bottom of the pool and wherein the pool cleaning robot may include a navigation module for navigating the pool cleaning robot to a hovering position above the underwater surface.

The pool cleaning robot may be configured to reach the hovering position without climbing on any pool structural element that leads to the underwater surface.

The pool cleaning robot may include a fluid conduit for selectively filling the ballast tank with fluid; wherein the fluid conduit has an opening that may be positioned at a lower part of the submersible pool cleaner.

The pool cleaning robot may include a fluid conduit for selectively filling the ballast tank with fluid; wherein the fluid conduit has an opening that may be positioned at an upper part of the submersible pool cleaner.

The pool cleaning robot may include a skimmer that may be positioned at a lower part of the submersible pool cleaner and a fluid conduit for selectively filling the ballast tank with fluid; wherein the fluid conduit fluidly couples the skimmer to the ballast tank.

The ballast tank may be configured to suck fluid through the fluid conduit when the pool cleaning robot is in an inverted position.

The pool cleaning robot when the pool cleaning robot may be configured to be in the inverted position when collecting floating dirt that floats on a fluid of the pool.

The pool cleaning robot may include a skimmer that may be positioned at an upper part of the submersible pool cleaner; and a fluid conduit for selectively filling the ballast tank with fluid; wherein the fluid conduit fluidly couples the skimmer to the ballast tank.

The ballast tank may be configured to suck fluid through the fluid conduit when the pool cleaning robot is in a non-inverted position.

The pool cleaning robot when the pool cleaning robot may be configured to be in the non-inverted position when collecting floating dirt that floats on a fluid of the pool.

The at least one cleaning element may include one or more bottom brushes that are coupled to a bottom of a housing of the cleaning robot and one or mode side suction brushes that are coupled to sides of the housing.

The at least one cleaning element may include one or more bottom brushes that are coupled to a bottom of a housing and one or more balancing wheels that are spaced apart from the one or more bottom suction brushes.

The at least one cleaning element may include an arm that extends from a housing of the submersible pool cleaner; wherein the at least one cleaning element may include an external suction brush that may be coupled to the arm.

The arm may be configured to place the external brush at an upper position that may be above the housing.

The when positioned at the upper position the external brush may be directed downwards.

The ballast tank may include piston that may be contained in a closed space; wherein the piston partitions the closed space to a first and second compartment; wherein the first compartment may be filled with gas; wherein the second compartment may be filled with fluid; wherein a movement of the piston within the closed space controls the buoyancy of the submersible pool cleaner.

The pool cleaning robot may include at least one sensor for sensing debris. The pool cleaning robot may include one or more sensors such as but not limited to a gyroscope, a geometrical sensor, an image sensor, an infrared sensor, a radar, a pressure sensor. The one or more sensors may positioned in any location of the pool cleaning robot. Sensors such as image sensors, geometrical sensors and infrared sensors may be at least partially positioned outside the housing of the pool cleaning robot or may have a field of view that extends through a window or aperture of the housing.

The underwater surface may be an upper surface of an underwater stair.

The propulsion module may include a jet generator that may be configured to generate one or more jets for propelling the submersible pool cleaner.

The propulsion module may include multiple impellers, wherein at least two impellers are oriented in relation to each other. These impellers may replace the fluid openings through which jets are ejected.

The pool cleaning robot may include a geometrical sensor that may be configured to detect various pool structural elements.

The propulsion module may include one or more jet generators that are configured to generate one or more fluid jets for maintaining the pool cleaning robot at a fixed position during at least a period during the hovering mode.

The one or more jet generators may be configured to (a) generate first fluid jets while the pool cleaning robot propagates towards the underwater surface, and (b) generate second fluid jets while the pool cleaning robot hovers over the underwater surface; wherein the first fluid jets are stronger than the second fluid jets.

The propulsion module may include a first jet generator and a second jet generator; wherein the first jet generator may be configured to generate first fluid jets while the pool cleaning robot propagates towards the underwater surface; wherein the second jet generator may be configured to generate second fluid jets while the pool cleaning robot hovers over the underwater surface; wherein the first fluid jets are stronger than the second fluid jets.

The pool cleaning robot may include an induction-based electrical charging module.

