Robot cleaning device

Abstract

A cleaning device comprising: a cleaner body (10); a front wheel (20) which is rotatably provided in a front area of ​​the cleaner body (10); a rear wheel (60) which is rotatably provided in a rear area of ​​the cleaner body (10); a first element (22) which is attached to an outer circumferential surface of the front wheel (20) and is designed to contact a cleaning object surface; a second element (62) which is attached to an outer circumferential surface of the rear wheel (60) and is configured to contact the surface of the object to be cleaned; and a rear motor (68) that turns the rear wheel (60); characterized by a front motor (48) which turns the front wheel (20); a control unit (200) that controls the front motor (48) and the rear motor (68), wherein the control unit (200) controls the front motor (48) and the rear motor (68) so that they rotate in opposite directions while cleaning is being carried out, and the cleaning body (10) is moved according to a rotation of the front wheel (20) and the rear wheel (60).

Description

Technical area

[0001] Embodiments of the disclosure relate to a robot cleaning device, and more particularly to a robot cleaning device capable of cleaning floors using water. background

[0002] A conventional robot cleaning device is a mechanism powered by battery power and configured to automatically become mobile according to a command from a microcomputer for controlling a cleaning system based on sensor information and program logic.

[0003] In addition, the conventional robot cleaning device is usually configured to perform a cleaning function by vacuuming dust dispersed on the floor below it along a route using a fan-assisted suction system, and to move with a mop attached to its lower portion to partially and secondarily remove unvaccumbed fine dust contaminants and stains on the floor. The mop is usually made of microfibers or fabric.

[0004] However, such a conventional robot cleaner cannot inject water into the mop. It is difficult to achieve a function similar to that of a wet mop using a conventional robot cleaner with a microfiber or cloth mop.

[0005] When the conventional robot cleaning device moves and pushes the mop, insufficient friction force is exerted on the mop and there may be disadvantages in terms of deteriorated cleaning efficiency.

[0006] DE 10 2015 104 250 A1 discloses a floor care robot with two drive wheels on opposite sides of the robot and a front support wheel as well as a brush roller which rotates via drive motors when the robot is in suction mode.

[0007] US 2015 / 0 236 640 A1 discloses a vacuum robot with rotating brushes on opposite sides of the robot's drive wheels.

[0008] WO 00 / 78 198 A1 discloses a cleaning robot that can perform both wet cleaning and vacuum cleaning during its movement.

[0009] Comparable devices are disclosed in DE 10 2005 005 948 A1 and in DE 20 2007 017 026 U1. RevelationTechnical Problem

[0010] Accordingly, the present disclosure is provided to address the above and other problems. Embodiments of the present disclosure provide a robotic cleaning device capable of cleaning floors using water.

[0011] Embodiments of the present disclosure also provide a robotic cleaning device that can remove used water from the floor after cleaning.

[0012] Embodiments of the present disclosure also provide a robot cleaning device configured to increase a frictional force using water during the cleaning process to increase cleaning efficiency. Technical solution

[0013] To achieve these objects and other advantages, a cleaning device according to the invention comprises the features of claim 1. Advantageous embodiments of the invention are claimed in the dependent claims. According to the purpose of the embodiments as embodied and broadly described herein, a roller-like or cylinder-like mop or brush is arranged on the underside of the cleaner body. Since rolling motion and sliding motion are generated together by the rotational speeds of the mop or brush and the frictional force with the floor, movement of the cleaner body and sweeping (friction mopping) for removing floor contaminants are performed simultaneously. In other words, the robot cleaning device according to the present disclosure includes the wheel for moving the cleaner body. The wheel, which has the function of moving the cleaner body, also has the function of cleaning the floor.

[0014] The weight of the robot cleaner is transferred to the wheel, and the wheel, which rotates in contact with the floor, increases friction with the floor. Accordingly, the robot cleaner exhibits higher cleaning performance under the same operating conditions.

[0015] The robot cleaning device according to the present disclosure includes a plurality of front wheels and a rear wheel. The front wheel has a wet cleaning function using a water supply system and generates the driving force for running in a desired direction. During forward movement, the rear wheel follows and passes through areas where wet cleaning is performed. The rear wheel is made of a fabric with a high moisture content and good wiping performance and absorbs the water dispersed by the front wheels.

[0016] The rear wheel rotates in the opposite direction to the front wheels, balancing the power to ensure it is applied in the correct places. The front and rear wheels, rotating in opposite directions, are simultaneously in a sliding state. The difference in traction forces also creates a certain movement to facilitate the running of the cleaner body. The difference in traction forces is generated by the difference between the rotational speeds and friction forces of the front and rear wheels.

[0017] In the robot cleaning device of the present disclosure, the water stored in the water tank is guided to the front wheels and supplied to the center of the front wheels. At this time, the water flows to the front wheels, which are rotating at high speed, and they rotate to be injected to an inner surface of the front wheel by the centrifugal force of the front wheel. Thus, the water exits through the outlet holes and reaches an outer surface of the mop pad / brush cloth to maintain the injected amount / moisture content for wet cleaning.

[0018] A nozzle can be positioned at the front wheel's rotation axis, maintaining a stable connection even during the front wheel's rotation. Likewise, the water injected by the nozzle cannot concentrate in any of the front wheels and is evenly distributed over the inner surface of the front wheel by centrifugal force.

[0019] The front wheels can change the rotational power provided by the engine into the torque (or speed) for driving, which is suitable for cleaning or running, using a deceleration device.

[0020] No water is applied to the rear wheel, allowing the rear wheel to remove any water remaining on the ground after the front wheel has been wet-cleaned. A polishing effect can also be expected due to rotational friction.

[0021] The robot cleaning device, which has completed the cleaning run, can easily perform a function as a means for facilitating the washing of the first and second members adhered to the outer peripheral surfaces of the front and rear wheels. To this end, a blade is provided in a receiving recess formed in a housing for partially receiving the front and rear wheels, and the blade is configured to contact the outer peripheral surfaces of the first and second members.

[0022] When the cleaner body rests on the cabinet, washing water in which detergent is dissolved is present in the receiving recess and the front wheels and the rear wheel are rotated to be washed.

[0023] When the cleaner body rests on the casing, water without detergent is present in the receiving recess and the front wheels and rear wheel are rotated to be rinsed.

[0024] When the cleaner body rests on the casing, there is no water, so the receiving recess is empty, and the front wheels and rear wheel are rotated to be wrung out and dried.

[0025] The front and rear wheels of the robot cleaner constantly perform rolling and sliding movements under different conditions with different friction forces. To control the movement of the cleaner body, the motor output can be adjusted and compensated for variations in acceleration and speed, and the motor drive can be controlled.

[0026] Planar motion is determined by the resultant force of the feed force generated by the toe angle (in / out), the resultant force generated by the forward and backward movement of the wheels, and the torque resultant force from the center of the cleaner body. The controller can calculate the RPM of the motors based on the acceleration and speed generated by the corresponding change, and control the motor output according to the calculated RPM.

[0027] The embodiments of the present disclosure can locate the robot cleaning device based on a relative distance in a space detected by two or more anchors or transducers configured to generate a specific radio wave signal (e.g., UWB, BLE, etc.). The controller can compare the arrival time of the current location information with the arrival time of the previous location information corresponding to the signal received by the signal receiving unit, and calculate speed information based on the result of the comparison process. Then, the controller can calculate errors of a remaining distance and location with respect to a target trajectory and a current position based on the location information, and estimate a target path by controlling the rotation of the motors.Embodiments of the present disclosure may provide a robot cleaning device comprising a cleaner body; a front wheel rotatably provided in a front portion of the cleaner body; a rear wheel rotatably provided in a rear portion of the cleaner body; a first member attached to an outer peripheral surface of the front wheel and configured to contact a cleaning object surface; a second member attached to an outer peripheral surface of the rear wheel and configured to contact the cleaning object surface; a water tank for supplying water to the front wheel; and a water supply line that supplies water from the water tank to the front wheel.

[0028] The front wheel may comprise a hollow cylindrical housing; and a plurality of outlet holes penetrating the cylindrical housing, wherein the hollow space communicates with the supply line, and water is supplied to the first element via the outlet holes by the centrifugal force generated upon rotation of the front wheel. In other words, no additional components need to be provided in the front wheel because the rotation of the front wheel, which is a fundamental function for distributing water in the front wheel, is utilized.

[0029] The robot cleaning device is typically designed to clean a flat floor. When water is supplied to the cavity from the water supply line, it is collected in a lower portion of the cylindrical housing. When the front wheel is rotated in this state, the water can be evenly distributed on an inner surface of the front wheel by centrifugal force and then guided to the first element after passing through the outlet holes.

[0030] A nozzle protruding into the interior of the cylindrical housing may be provided in the rotational axis of the cylindrical housing. The water supply line may supply water to the nozzle. The nozzle protrudes into the interior of the cavity, allowing water to be supplied to the entire area of ​​the front wheel along the rotational axis of the front wheel. A pump may be provided in the water supply line, and the pump may supply water to the front wheel via the water supply line.

[0031] The front wheel may include a first front wheel and a second front wheel provided on both sides of the cleaner body in symmetry with respect to the center of the cleaner body. The water supply line may include an inlet line that supplies water from the water tank to the pump, and a first outlet line and a second outlet line that branch the water supplied from the pump to the first front wheel and the second front wheel, respectively. The first outlet line and the second outlet line are provided in a region where the front wheel and the second front wheel oppose each other to prevent the force from being applied to one side of the robot cleaner when supplying water to the first and second front wheels.

[0032] The pump is designed to supply water to the front wheel while the front wheel is rotating, preventing water from accumulating in the lower part of the front wheel. The first element has a lower moisture content percentage than the second element, allowing the water absorbed by the first element to moisten the surface of the cleaning object, while the second element can absorb the remaining water on the surface of the cleaning object.

[0033] The horizontal width of the front wheel is narrower than that of the rear wheel. The rear wheel can follow the locus of the front wheel running on the surface of the object to be cleaned and complete the cleaning.

[0034] When viewed from above, the front wheel and the water tank may overlap.

[0035] The front wheel may include the first front wheel and the second front wheel arranged on both sides of the cleaner body symmetrically with respect to the center of the cleaner body. A first front motor may be further provided to drive the first front wheel, and a second front motor may be further provided to drive the second front wheel. The first front motor, the second front motor, and the rear motor can control the running of the robot cleaner by being independently and separately driven. The first front motor, the second front motor, and the rear motor are independently and separately driven, and the cleaning performance of the robot cleaner can then be increased accordingly.

[0036] The first front wheel and the second front wheel may be arranged opposite each other, with a forward angle of 180° between a rotational axis of the first front wheel and a rotational axis of the second front wheel. Alternatively, the first front wheel and the second front wheel may be arranged opposite each other, with a rearward angle of 180° between a rotational axis of the first front wheel and a rotational axis of the second front wheel.

[0037] Embodiments of the present disclosure may further include a housing upon which the cleaner body may rest. The housing may include a support portion connected between the upper portion of the wheel and the lower portion of the wheel to support the cleaner body. The user may rest the cleaner body on the housing.

[0038] Washing water is stored in the housing and the first and second elements are saturated with the washing water so that a washing process for the first and second elements can be carried out.

[0039] A blade may be provided in the housing to contact the first member or the second member. When the front wheel and rear wheel are rotated, foreign substances adhering to the first and second members can be removed.

[0040] A pair of blades may be provided and contact both sides of the first element or the second element.

[0041] A battery can be provided further inside the cleaner body. Viewed from above, the battery can overlap with the water tank, and the loads of the front and rear wheels can be evenly distributed.

[0042] Embodiments of the present disclosure may provide a robot cleaning device comprising a cleaner body; a front wheel rotatably provided in a front portion of the cleaner body; a rear wheel rotatably provided in a rear portion of the cleaner body; a first member attached to an outer peripheral surface of the front wheel and configured to contact a cleaning object surface; a second member attached to an outer peripheral surface of the rear wheel and configured to contact the cleaning object surface; a front motor that rotates the front wheel; a rear motor that rotates the rear wheel; and a controller that controls the front motor and the rear motor, the controller controlling the front motor and the rear motor to rotate in opposite directions while cleaning is performed.The front motor and the rear motor are rotated in opposite directions and sliding of the front and / or rear wheels occurs.

[0043] In other words, the running direction of the cleaner body moved by the rotation of the front wheel is different from that of the cleaner body moved by the rotation of the rear wheel. Sliding occurs at the front or rear wheel, increasing the friction force. Accordingly, the force exerted by the first and second elements on the cleaning object surface becomes stronger, and the cleaning object surface can be cleaned using a relatively stronger force. Compared with pushing the cloth attached to the cleaner body and mopping the floor, the robot cleaning device can perform an improved cleaning process.

[0044] The controller can control the front and rear motors, and the rear motor can be set to operate at a lower speed than the front motor. The cleaner body can be moved in the opposite direction to the rotation of the rear motor. The rear motor creates a sliding action, facilitating the scrubbing of the first and second elements with greater force.

[0045] The front wheel includes a first front wheel and a second front wheel, which are provided on both sides of the cleaner body in symmetry with respect to the center of the cleaner body. The front motor may include a first front motor that rotates the first front wheel and a second front motor that rotates the second front wheel. The controller may rotate the first front motor and / or the second front motor in the direction opposite to the rotation direction of the rear motor.

[0046] The rear motor can rotate at a predetermined speed that is lower than the higher of the two speeds at which the first front motor and second front motor rotate. The rear motor can perform the function of increasing friction rather than the function of moving the cleaner body.

[0047] The cleaning device may further comprise an acceleration detection unit that detects the acceleration of the cleaner body and a speed detection unit that detects the speed of the cleaner body, wherein the controller compensates the output of the motor based on the information detected by the acceleration detection unit and the speed detection unit.

[0048] The cleaning device may further comprise a signal receiving unit that receives a radio wave transmitted from an external device, wherein the controller locates the cleaner body based on the signal received by the signal receiving unit. The signal receiving unit may receive the radio wave transmitted from the transmission units arranged at different locations.

[0049] The front and rear wheels rotate in opposite directions, resulting in slippage. Accordingly, errors that occur when determining the position or movement of the cleaner body using the torque or rotation direction of the front or rear wheels cannot be corrected. In other words, wheel slippage cannot be detected even if the torque is measured using the encoder installed in the motor. Accordingly, it is preferable to determine the position or movement direction of the robot cleaner using external transmission units instead of the conventional encoder. Beneficial effects

[0050] The embodiments have the following advantageous effects. The robot cleaning device performs wet cleaning using water, and the foreign substances adhering to the floor can be wiped up and removed.

[0051] Furthermore, the robot cleaning device can increase the friction force with the floor, thus improving the cleanliness of wet cleaning. In other words, the wet element is attached to the rotary wheel, and the rotary wheel rotates. Accordingly, the wet cleaning element, which not only passes over the floor, can create a hand-wiping and scrubbing effect.

[0052] Furthermore, the water tank containing the water can be overlapped with the floor mopping element, and the load of the water tank is applied to the element to increase the friction force when wet cleaning is performed. Accordingly, the wet cleaning performance can be increased.

[0053] After performing wet cleaning of the floor, the remaining moisture or water on the floor can be removed, preventing water stains. After the saturated element completes wet cleaning, the dry element performs floor cleaning and performs double cleaning of the same floor or the same surface to be cleaned.

[0054] Using the centrifugal force generated by the rotation of the wheel, water can be evenly distributed on the wet floor cleaning element and the moisture content percentage of the wet element can be appropriately adjusted.

[0055] The robot cleaner can obtain accurate information for the position of the cleaner body using an external signal for locating the cleaner body.

[0056] The robot cleaning device can remove the foreign substances adhering to it using water. Description of the drawings Fig. 1 is a perspective diagram showing an embodiment of the present disclosure; Fig. 2 is a diagram showing a lower portion of the Fig. 1 shows; Fig. 3 is a side sectional view of the Fig. 1; Fig. 4 is a diagram showing key parts of the Fig. 1 shows; Fig. 5 is a diagram showing a front wheel; Fig. 6 is a conceptual diagram of various examples of the present disclosure; Fig. 7 is a control block diagram showing the embodiment of the present disclosure; Fig. 8 and Fig. 9 are diagrams showing a housing in which the embodiment of the present disclosure is stably placed; Fig. 10 is a diagram showing another embodiment of the present disclosure. Best embodiment

[0057] With reference to the attached drawings, exemplary embodiments of the present disclosure will be described in detail according to an embodiment of the present disclosure.

[0058] Regardless of reference numerals, the same or equivalent components are denoted by the same reference numerals, and a description thereof will not be repeated. For the sake of brevity of the description, with reference to the drawings, the sizes and profiles of the elements shown in the attached drawings may be enlarged or reduced, and it should be understood that the embodiments presented herein are not limited by the attached drawings.

[0059] Fig. 1 is a perspective diagram showing an embodiment of the present disclosure. Fig. 2 is a diagram showing a lower portion of the Fig. 1 shows. Fig. 3 is a side sectional view of the Fig. 1 and Fig. 4 is a diagram showing key parts of the Fig. 1 shows. Fig. Figure 5 is a diagram showing a front wheel.

[0060] Referring to the Fig. 1 to 5, the robot cleaning device according to an embodiment of the present disclosure includes a cleaner body 10 defining an external appearance thereof; a front wheel 20 rotatably provided in a front portion of the cleaner body 10; a rear wheel 60 rotatably provided in a rear portion of the cleaner body 10; a first member 22 attached to an outer peripheral surface of the front wheel 20 to contact a cleaning object surface; a second member 62 attached to an outer peripheral surface of the rear wheel 60 to contact a cleaning object surface; and a water tank for supplying water to the front wheel 20.

[0061] The first element 22 and the second element 62 are configured to remove dust and foreign substances from the cleaning object surface (e.g., the floor) during contact with the cleaning object surface.

[0062] The first member 22 and second member 62 rotate together with the front wheel 20 and the rear wheel 60, respectively, while contacting the cleaning object surface. Compared with the cleaning efficiency of the conventional robot cleaner that sweeps the floor along the movement of the cleaner body 10, the robot cleaner is capable of exerting a higher friction force on the cleaning object surface and can exhibit increased cleaning efficiency.

[0063] As in the Fig. 1, the water tank 80 may be provided near the center of the cleaner body 10 or may be arranged slightly closer to the front wheel 20 with respect to the center of the cleaner body 10.

[0064] As in the Fig. As shown in Figure 2, the front wheel 20 includes a first front wheel 30 and a second front wheel 40 arranged symmetrically on both sides relative to the center of the cleaner body 10. In other words, the front wheel 20 is formed of two wheels, not one wheel. The first front wheel 30 and the second front wheel 40 are arranged opposite each other.

[0065] The rear wheel 60, which is a single wheel, may be arranged behind the front wheel 20. In a case where the front wheel 20 includes the first front wheel 30 and the second front wheel 40, the first member 22 is not arranged between the first front wheel 20 and the second front wheel 30, so that a certain area may exist that is not cleaned by the first member 22. However, the rear wheel 60 is configured as a single wheel, and the second member 62 contacts the entire area where the rear wheel 60 rotates to perform cleaning of the cleaning object surface.

[0066] Referring to the Fig. 4, the illustrated embodiment may include a water supply line for supplying water to the front wheel 20 from the water tank 80 to the front wheel 20. A pump 90 is provided in the water supply line to generate the pressure that moves the water stored in the water tank 80 to the front wheel 20.

[0067] The water supply line includes an inlet line 94 for supplying water from the water tank 80 to the pump 90; a transmission line 97 supplying water from the pump 90 to the branched portion of the first front wheel 30 and the second front wheel 40; and a first outlet line 98 and a second outlet line 99 branched to the first front wheel 30 and the second front wheel 40.

[0068] The water flowing from the water tank 80 is guided along the inlet line 94 to the pump 90 and, after passing the pump 90, flows to the transmission line 97. Thus, the water is branched from the transmission line 97 to the first outlet line 98 and the second outlet line 99 and then supplied to the first front wheel 30 and the second front wheel 40 in a divided manner.

[0069] The first outlet line 98 and the second outlet line 99 are arranged symmetrically with respect to the center of the cleaner body 10 to stop the force that might be exerted on one side of the cleaner body 10 by the flow of water flowing to the first front wheel 30 and the second front wheel 40. Thus, noise or vibration that might be generated by the water flow can be prevented and driving stability can be ensured.

[0070] The first outlet pipe 98 and the second outlet pipe 99 are provided in a region where the first front wheel 30 opposes the second front wheel 40, respectively, so that they can guide the water to the first front wheel 30 and the second front wheel 40, respectively. In a plan view of the cleaner body 10, the front wheel 20 and the water tank 80 overlap each other. Since it holds water, the water tank 80 is the component that has a relatively larger load than the other components of the robot cleaner. When the water tank 80 overlaps with the front wheel 20, the load of the water tank 80 can be largely concentrated on the front wheel 20, and the frictional force of the front wheel 20 can be increased. The frictional force of the first member 22 with respect to the cleaning object surface is increased, and cleaning efficiency can be improved when the wet first member 22, which is in contact with the cleaning object surface, performs cleaning.

[0071] The front wheel 20 includes a hollow cylindrical housing 31 and a plurality of outlet holes 34 penetrating the cylindrical housing 31. The hollow space 33 communicates with the water supply line, so that water is supplied to the first element 20 via the outlet holes 34 when the front wheel 20 begins to rotate.

[0072] A nozzle 36 may be provided further along the rotational axis of the cylindrical housing 31 and protrude into the cylindrical housing 31. The water supply line is configured to supply water to the nozzle 36, and a corresponding number of nozzles 36 are provided in the first front wheel 30 and the second front wheel 40, respectively. The nozzles 36 are connected to the first outlet line 98 and the second outlet line 99 to supply water to the first front wheel 30 and the second front wheel 40.

[0073] The first front wheel 30 and the second front wheel 40 are formed with the same structure and arranged symmetrically in different positions.

[0074] Meanwhile, the pump 90 is activated to supply water to the front wheel 20 while the front wheel 20 rotates. When the front wheel 20 begins to rotate, a centrifugal force is generated in the front wheel 20 and the water is evenly distributed throughout the front wheel 20.

[0075] A gear box 24 may be provided in a region opposite the nozzle 36 in the first front wheel 30 and transmit the rotational power generated by the engine to the first front wheel 30. As shown in Fig. 5, the nozzle 36 is located in the left area of ​​the first front wheel 30, and the gear box 24 is located in the right area of ​​the first front wheel 30. In this example, both the nozzle 36 and the gear box 24 are connected to the shaft of the first front wheel 30.

[0076] The gearbox 24 changes the speed or power generated in the engine and transmits the changed speed or power to the first front wheel 30.

[0077] The outlet holes 34 provided in the cylindrical housing 31 are evenly distributed in the cylindrical housing 31. When the water injected from the nozzle 36 is evenly distributed on the cylindrical housing 31, the outlet holes 34 provide paths for supplying water to the first element 22.

[0078] The first element 22 is supplied with water passing through the outlet holes 34 and performs cleaning with the water and in contact with the surface of the object to be cleaned.

[0079] The output holes 34 are formed in the cylindrical housing 31 in a plurality of lines, and the lines are arranged at predetermined intervals.

[0080] The first element 22 has a lower percentage of water content than the second element 62.

[0081] The first element 22 is supplied with water and, in a state where it contains water, performs cleaning for the surface of the object to be cleaned. The second element 62 is configured to remove the water remaining on the surface of the object to be cleaned as it moves over the area that the first element 22 has just passed. In other words, the second element 62 comprises a material that can absorb the water used by the first element from the surface of the object to be cleaned and does not leave water stains on the surface of the object to be cleaned.

[0082] In particular, the first element 22 may be made of a specific material with a relatively high porosity, such as a washing sponge, and the second element 62 may be made of a specific material with a relatively low porosity, such as microfiber. The first element 22 and the second element 62 have different porosities. Even if the front wheel 20 and the rear wheel 60 rotate at the same speed, the frictional force exerted by the front wheel 20 may be different from the frictional force exerted by the rear wheel 60 on the same cleaning object surface. When the first element 22 and the second element 62 clean the same area, different frictional forces can provide cleaning diversity, and the cleaning efficiency can then be increased.

[0083] Fig. 6 is a conceptual diagram of various examples of the present disclosure.

[0084] In an example of the present disclosure shown in Fig. 6a, the first front wheel 30 and the second front wheel 40 may be arranged opposite each other, wherein a forward-facing angle of 180° may be present between a rotational axis of the first front wheel 30 and a rotational axis of the second front wheel 40.

[0085] In this example, the horizontal width (11) of the front wheel 20, comprising the first front wheel 30 and the second front wheel 40, is smaller than the horizontal width (12) of the rear wheel 60, so that the rear wheel 60 can pass the area that the front wheel has passed.

[0086] Since the front wheel performs cleaning using the wet first member 22, it is relatively likely that water will remain on the cleaning object surface cleaned by the first member 22. The second member 62 absorbs the remaining water and completes the cleaning.

[0087] In another example of the present disclosure, which is shown in Fig. 6b, the first front wheel 30 and the second front wheel 40 may be arranged opposite each other, wherein a rearward angle of 190° or less may be present between the rotational axis of the first front wheel 30 and the rotational axis of the second front wheel 40.

[0088] Also in this example, the horizontal width (11) of the front wheel 20, comprising the first front wheel 30 and the second front wheel 40, is smaller than the horizontal width (12) of the rear wheel 60.

[0089] When the front wheel 30 and the second front wheel 40 are inclined with respect to the front surface as shown in the Fig. 6a and Fig. 6b, the control of the robot cleaning device for changing a direction of the cleaner body 10 can be simplified.

[0090] In another example of the present disclosure, as set forth in the Fig. 6c, the rotational axis of the first front wheel 30 and the rotational axis of the second front wheel 40 are arranged substantially on the same extended line. The horizontal width (11) of the front wheel 20, comprising the first front wheel 30 and the second front wheel 40, is smaller than the horizontal width (12) of the rear wheel 60. The rotational operation of the Fig. 6c is performed by differentiating the rotational speed of the first front wheel 30 from that of the second front wheel 40.

[0091] Fig. 7 is a control block diagram showing an embodiment of the present disclosure.

[0092] Referring to the Fig. 7, the embodiment of the present disclosure includes a front motor 38 that drives the first front wheel 30; a second front motor 48 that drives the second front wheel 40; and a rear motor 68 that drives the rear wheel 60.

[0093] In other words, the two front wheels 20 and the one rear wheel 60 are driven by different motors, so that the two front wheels 20 and the one rear wheel 60 are different from each other and are controlled independently.

[0094] The illustrated embodiment may include a controller 200 for controlling the first front motor 38, the second front motor 48, and the rear motor 68.

[0095] The illustrated embodiment may further include an acceleration detection unit 210 that detects an acceleration of the cleaner body 10 and a speed detection unit 220 that detects a speed of the cleaner body 10. The controller 200 is capable of controlling the motors by compensating the output of the motors based on the information detected by the acceleration detection unit 210 and the speed detection unit 220.

[0096] The illustrated embodiment may further include a signal receiving unit 230 that receives an electromagnetic wave transmitted from an external device. The controller 200 can locate the cleaner body 10 based on the signal received by the signal receiving unit 230. For this purpose, an external locating device may be capable of transmitting a radio wave that is receivable by the signal receiving unit 230.

[0097] A plurality of signal-oriented devices are provided at different locations, so that the signal receiving unit 230 can receive the radio waves transmitted by transmitters of the signal-oriented devices placed at different locations. The signal receiving unit 230 compares the strengths and directions of the signals received from the transmitters with each other when the signals are received, and also compares the information received at a previous location with the information received at the current location, so that it can determine the location or direction based on the comparison result.

[0098] The controller 200 controls the front motor and the rear motor 68 to rotate in opposite directions while cleaning is performed. If the front motor includes the first front motor 38 and the second front motor 48, the controller may control the first front motor 38 and / or the second front motor 48 to rotate in the opposite direction to the direction in which the rear motor 48 rotates.

[0099] When the front motor and the rear motor rotate in opposite directions, for example, when the front motor is rotated in the counterclockwise direction and the rear motor 68 is rotated in the clockwise direction, as viewed from the Fig. 3, the front wheel 20 is turned counterclockwise and the rear wheel 60 is turned clockwise.

[0100] The two wheels installed at different positions of the cleaner body 10 are rotated in opposite directions, and one or more wheels slide. Such sliding occurs even when the force applied opposite to the driving direction of the cleaner body 10 is not applied in a state where the wheels are stationary, merely to increase the frictional force exerted by the robot cleaner on the surface of the object to be cleaned.

[0101] Accordingly, the frictional forces exerted by the first member 22 and the second member 62 on the cleaning object surface are increased, and the robot cleaning device can clean the cleaning object surface with a greater force, only to improve the cleaning performance.

[0102] The controller 200 can control the cleaner body 10 so that it does not move even when the front and rear wheels 20 and 60 rotate in opposite directions by adjusting the speeds of the front and rear motors. In this example, deep cleaning can be performed for areas that are currently in contact with the first element 22 and the second element 62 of the cleaner body 10.

[0103] As mentioned above, the wheels of the illustrated embodiment slide. If an encoder is used to detect the motor speed, large errors that occur when detecting the position and direction of the robot cleaning device cannot be compensated for. Accordingly, the illustrated embodiment includes a transmission unit for generating a signal external to the robot cleaning device, and the signal reception unit receives a signal from the external transmission unit only to locate the robot cleaning device based on the received signal.

[0104] It is possible that the motor speed is controlled and compensated using the encoder. The encoder cannot provide reliable information that can be used to determine the position of the robot cleaning device.

[0105] The front wheel 20 includes two wheels, and the rear wheel 60 includes a single wheel, so that the robot cleaner can be moved by the front wheel 20. In this example, the controller 200 can control the front motor and the rear motor 68 to make the rotation of the rear motor 68 slower than that of the front motor.

[0106] When the rotational speed of the front motor is higher than that of the rear motor 68, the force applied to the front wheel 20 becomes strong enough for the front wheel 20 to move the cleaner body. The rear motor 68 performs the function of generating sliding. When the rotational speed of the rear motor is higher, the degree of sliding becomes greater. When the rotational speed of the rear motor is lower, the degree of sliding becomes smaller. Accordingly, the cleaner body 10 can be moved in the direction opposite to the rotational direction of the rear motor.

[0107] Fig. 8 and Fig. 9 are diagrams showing a housing in which the embodiment of the present disclosure is stably placed.

[0108] Referring to the Fig. 8 and Fig. 9, the robot cleaning device may further comprise a housing on which the cleaner body 10 is placed. The housing 100 includes a support unit 110 connected between the front wheel 20 and the rear wheel 60 to support the cleaner body 10.

[0109] The housing 100 is placed below the cleaner body 10, and the cleaner body 10 rests on the housing 100.

[0110] The support unit 110 is arranged higher than a bottom surface of the housing 100 and fitted between the front wheel 20 and the rear wheel 60 to be connected to the cleaner body 10.

[0111] Wash water may be present in the housing 100 and the first element 22 and the second element 62 are well moistened.

[0112] Furthermore, a blade 106 may be provided in the housing 100 to contact the first member 22 or the second member 62. The blade 106 may be provided on both sides of the first member 22 and both sides of the second member 62 to contact the first member 22 and the second member 62 when the first member 22 and the second member 62 are rotated. When the first member 22 and the second member 62 begin to rotate, the blade 106 contacts the first member 22 and the second member 62, and foreign substances adhered to the first member 22 and the second member 62 are separated.

[0113] When the cleaner body 10 rests on the housing 100, washing water can be retained in the housing 100, and the front wheel 20 and the rear wheel 60 can rotate while the washing water is retained in the housing 100. Then, washing water can be absorbed into the front wheel 20 and the rear wheel 60, and friction is generated against the blade 106, so that the first member 22 and the second member 62 can be washed (a washing process).

[0114] When the cleaner body 10 rests on the housing 100, water without detergent can be stored in the housing 100. When the front wheel 20 and the rear wheel 60 rotate, the water stored in the housing can be absorbed by the front wheel 20 and the rear wheel 60, and friction is generated against the blade 106, so that the first element 22 and the second element 62 can be rinsed (one rinsing process).

[0115] In addition to the washing and rinsing processes, nothing can be present in the housing 100 (an empty state) while the cleaner body 10 rests on the housing 100. When the front wheel 20 and the rear wheel 60 are rotated in the empty state, the water contained in the first element 22 and the second element 62 can be separated by centrifugal force. In other words, the first element 20 and the second element 62 can be wrung out (a wringing process) while the cleaner body 10 rests on the housing 100.

[0116] Fig. 10 is a diagram showing another embodiment of the present disclosure.

[0117] Referring to the Fig. 10, the first front wheel 30 and second front wheel 40 are arranged in an upper region within the cleaner body 10. The water tank 80 partially overlaps the first front wheel 30 and second front wheel 40.

[0118] A battery 941 is provided, and the electricity supplied from an external power source is stored in the battery 941 and then supplied to the motor. The battery 941 may be arranged overlapping the water tank 80.

[0119] A circuit board 92 is mounted below the water tank 80 and the rear wheel 60 is arranged below the circuit board 92.

[0120] The battery 941 and the water tank 80 are relatively heavy compared to other components in the robot cleaner. Therefore, the battery 941 and the water tank 80 are arranged near the center of the cleaner body 10 and overlapped with each other so that the load of the battery 941 is not concentrated on either the front wheel 20 or the rear wheel 60. Thus, the friction of the front wheel 20 and the rear wheel 60 can be uniformly increased, and a force exerted on the first member 22 and the second member 62 for contact with the ground can be uniformly increased.

[0121] Since the present features may be embodied in various forms without departing from their nature, it is to be understood that the above-described embodiments are not limited by any of the details of the foregoing description unless otherwise specified, but should be considered broadly within the scope defined by the appended claims, and therefore all changes and modifications that come within the measure and spirit of the claims, or equivalents of the measure and spirit, are intended to be embraced by the scope of the appended claims.

Claims

[1] A cleaning device comprising: a cleaner body (10); a front wheel (20) rotatably provided in a front portion of the cleaner body (10); a rear wheel (60) rotatably provided in a rear portion of the cleaner body (10); a first member (22) attached to an outer peripheral surface of the front wheel (20) and configured to contact a cleaning object surface; a second member (62) mounted on an outer peripheral surface of the rear wheel (60) and configured to contact the cleaning object surface; and a rear motor (68) which rotates the rear wheel (60); characterized by a front motor (48) which rotates the front wheel (20); a controller (200) which controls the front motor (48) and the rear motor (68), wherein the controller (200) controls the front motor (48) and the rear motor (68) to rotate in opposite directions while cleaning is being performed, and the cleaner body (10) is moved in accordance with rotation of the front wheel (20) and the rear wheel (60). [2] The cleaning device according to claim 1, wherein the controller (200) controls the front motor (48) and the rear motor (68) and controls the rear motor (68) to have a lower speed than the front motor (48). [3] The cleaning device according to claim 1, wherein the cleaner body (10) is moved in the direction opposite to the direction of rotation of the rear motor (68). [4] The cleaning device according to claim 1, wherein the front wheel (20) comprises a first front wheel (30) and a second front wheel (40) provided in both sides of the cleaner body (10) in symmetry with respect to the center of the cleaner body (10), wherein the front motor (48) comprises a first front motor (38) for driving the first front wheel (30) and a second front motor (48) for driving the second front wheel (40), and wherein the controller (200) controls one of the first front motor (38) and the second front motor (48) to rotate in the opposite direction to the rear motor (68). [5] The cleaning device according to claim 4, wherein the rear motor (68) is rotated at a predetermined speed which is lower than the higher speed of the two speeds at which the first front motor (38) and the second front motor (48) are rotated. [6] The cleaning device according to claim 1, further comprising: an acceleration detection unit (210) that detects the acceleration of the cleaner body (10); a speed detection unit (220) that detects the speed of the cleaner body (10); wherein the controller (200) compensates the output of the motor based on the information detected by the acceleration detection unit (210) and the speed detection unit (220). [7] The cleaning device according to claim 1, further comprising: a signal receiving unit (230) that receives a radio wave transmitted from an external device, wherein the controller (200) locates the cleaner body (10) based on the signal received by the signal receiving unit (230). [8] The cleaning device according to claim 7, wherein the signal receiving unit (230) receives the radio wave transmitted from the transmission units arranged at different locations. [9] The cleaning device according to claim 1, further comprising: a water tank (80) which supplies the front wheel (20) with water; and a water supply line that carries water from the water tank (80) to the front wheel (20), [10] The cleaning device according to claim 9, wherein the front wheel (20) comprises: a hollow cylindrical housing (31); a plurality of exit holes (34) penetrating the cylindrical housing (31), wherein the cavity (33) is in communication with the supply line and water is supplied to the first element (22) via the outlet holes (34) by the centrifugal force generated when the front wheel (20) is rotated. [11] The cleaning device of claim 1, wherein a percentage of a water content of the first element (22) is less than a percentage of a water content of the second element (62). [12] The cleaning device according to claim 10, wherein the first element (22) has a relatively larger porosity and the second element (62) has a relatively smaller porosity.

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