Patent Description:
The present disclosure also relates to a depth sensor control system to accurately measure a depth of an object by automatically adjusting an amount of light received by a sensor.

Cleaners remove foreign substances and clean an indoor space and vacuum cleaner is generally used to suction the foreign substances based on a suction power.

In recent years, robot cleaners have been developed to perform autonomous driving to move by themselves and remove foreign substances from the indoor floor without user's labor.

The robot cleaner detects a cleaning area and obstacles using a sensor of the cleaner and automatically performs cleaning while moving within the cleaning area. If the robot cleaner consumes a power of a battery in the device, the robot cleaner moves to a charging station which is provided at a predetermined position, charges the battery, and returns back to its original position to perform the cleaning.

In addition, an agitator is disposed under the robot cleaner, and when driving, rotates to sweep away dust or dirt from the floor, thereby facilitating suction.

Hereinafter, with reference to <CIT> and <CIT>, a robot cleaner in related art is described.

<FIG> show a robot cleaner in related art. Reference numerals shown in the drawings are applied only to the description of <FIG>.

Referring to <FIG> and <FIG>, a robot cleaner in the related art disclosed in a <CIT> includes a main body <NUM> defining an appearance, a dust collecting device <NUM> disposed in the main body <NUM> and to collect dust, and a blowing device <NUM> that communicates with the dust collecting device <NUM> and configured to generate a suction force to suction dust.

A suction inlet <NUM> is defined at a lower portion of the main body <NUM> defining the appearance to suction dust or the like from the floor. The main body <NUM> includes a discharge outlet <NUM> and an exhaust outlet <NUM> at an upper portion thereof, the discharge outlet <NUM> discharges air suctioned by the blowing device <NUM> to an outside of the main body <NUM> and the exhaust outlet <NUM> discharges dust collected by a dust collecting device <NUM> to a docking station when a robot cleaner <NUM> is docked with the docking station (not shown).

A rotating brush <NUM> (i.e., an agitator) is disposed under the main body <NUM> to sweep or scatter dust or dirt from the floor, thereby increasing duct suction efficiency.

However, the robot cleaner in the related art has a problem in that the robot cleaner suctions a large obstacle based on an increased suction power, and thus, the robot is constrained by the obstacle.

Referring to <FIG>, the robot cleaner in the related art disclosed in <CIT> includes an agitator <NUM> disposed inside a suction head and rotated by the motor <NUM> and a speed detection means <NUM> to detect a speed based on a number of rotations of the agitator <NUM>. The robot cleaner further includes a control means <NUM> to compare a speed detection signal output by the speed detection means <NUM> with a speed command value preset by a user, and output a drive control signal based on a result of comparing therm.

However, there is a problem in that, if the agitator <NUM> is caught by foreign substrates and stops rotation, the robot cleaner in <FIG> has difficulty in responding to the situation.

In addition, there is a problem in that, as the robot cleaner in the related art may not distinguish avoiding obstacles from climbing obstacles, the robot cleaner in the related art avoids obstacles, thereby reducing the cleaning area.

In addition, there is a problem in that the robot cleaner in the related art does not identify an obstacle and is repeatedly constrained by a same object, thereby blocking proper cleaning of the robot cleaner in the related art.

For reference, reference numerals used in <FIG> are applied only to <FIG>.

For example, an automatic exposure control generally used for an image sensor is designed to maintain target brightness of continuous input images, and such exposure control is performed by controlling a gain and an exposure time of the image sensor.

An automatic exposure control device receives image data from the image sensor, processes the received image data, and transmits, to the sensor, information on accumulated time and gain determined to be appropriate.

Exposure is determined based on a charge integration time and gain. The charge integration time refers to a time taken until one pixel is reset, receives light again, and reads an amount of integrated charge. In addition, the gain refers to a degree of amplifying a charge generated in proportion to the integration time by an analog or digital method. In general, when a sufficient amount of lighting is provided, exposure control is performed by maintaining the gain at <NUM> and only adjusting the charge integration time.

However, in an environment in which insufficient lighting is provided, a sufficiently bright image may not be obtained even when the exposure time is maximized. A gain greater than <NUM> may be applied to obtain a bright image.

Hereinafter, with reference to <CIT> and <CIT>, an image sensor to perform automatic exposure control in the related art is described.

<FIG> and <FIG> show an image sensor in related art.

Referring to <FIG>, a brightness estimation apparatus <NUM> of an image sensor in related art according to <CIT> includes an automatic exposure control device <NUM>, and a brightness detector <NUM>, a look up table (LUT) generator <NUM>, and a histogram generator <NUM>.

The image sensor <NUM> includes a capturing sensor to output an RGB signal based on an intensity of light. The brightness detector <NUM> maps a sensor gain and an exposure time output from the automatic exposure control device <NUM> to a sensor gain and an exposure time stored in the LUT generator <NUM> and generate brightness information of any color region and brightness information of the color region per one pixel.

However, there is a limitation in that the method is difficult to be directly applied to a 3D sensor to obtain distance information on distance from an object, which is studied recently.

Referring to <FIG>, a laser device <NUM> according to <CIT> adjusts light output using a laser optical sensor.

For example, the laser device <NUM> uses a sensor <NUM> to measure infrared rays emitted from a laser light (A)-transmitting point of a processing material (B) or measure a temperature of the transmitted point and a control module <NUM> to adjust output in real time.

In this case, the control module <NUM> controls the sensor <NUM> to measure a temperature or an amount of light of the laser-transmitted point for maintaining an appropriate amount of light incident on the sensor <NUM> and controls a driving signal applied to a laser module <NUM> based on the measured temperature and amount of light. A light guide <NUM> and a light transmitter <NUM> each output the laser light (A) output from the laser module <NUM>.

However, there is a problem in that the light output adjust device requires an additional sensor to measure the temperature of and the amount of light at the transmitted point, resulting in an increase in manufacturing cost.

In addition, the light output adjust device in the related art takes a relatively longer time to measure the temperature of the transmitted point, thereby increasing a time period for which the light amount is adjusted.

For reference, reference numerals used in <FIG> and <FIG> are applied only to <FIG>.

<CIT>, <CIT>, <CIT> and <CIT> relate to robot cleaners.

The present invention provides a robot cleaner including a constraint prevention filter to prevent the cleaner from being constrained resulting from a cleaning nozzle being caught by an obstacle.

The present disclosure also provides a robot cleaner configured to control a constraint prevention filter to avoid an obstacle or climb an obstacle according to types of obstacles.

The present disclosure further provides a robot cleaner to store types and positions of obstacles and move while avoiding the obstacles based on stored data.

The present disclosure further provides a depth sensor control system configured to automatically adjust an amount of light to accurately measure a depth of an object.

The present disclosure further provides a depth sensor control system to reduce cost incurring for controlling the amount of light by adjusting the amount of incident light by performing a function for measuring the infrared intensity of the depth sensor.

The present disclosure further provides a depth sensor control system to provide a fast response time to control an amount of light for accurately measuring depth of an object.

The objects of the present disclosure are not limited to the above-mentioned objects and other objects and advantages of the present disclosure which are not mentioned may be understood by the following description and more clearly understood by the embodiments of the present disclosure. It will also be readily apparent that the objects and the advantages of the present disclosure may be implemented by features described in claims and a combination thereof.

The invention is defined in the independent claim. Dependent claims describe preferred embodiments.

According to the present invention, a robot cleaner includes a constraint prevention filter disposed in front of an agitator to prevent the robot cleaner from being constrained resulting from a cleaning nozzle being caught by an obstacle.

In addition, the robot cleaner according to the present disclosure includes a controller to classify an obstacle detected in front of the robot cleaner into an avoiding obstacle or a climbing obstacle and control a position of the constraint prevention filter, thereby selecting an appropriate operation method according to types of obstacles.

In addition, according to the present disclosure, the robot cleaner includes a controller to control a memory to store a type and a position of the detected obstacle and determine a driving method based on the stored data in a next driving, thereby preventing the robot cleaner from being continuously constrained by a same obstacle.

In addition, according to an example, a depth sensor control system includes a sensor controller to control an exposure time of a light receiver and an output of a light emitter to automatically adjust an appropriate amount of light for measuring the depth of a target object.

In addition, according to an example, the depth sensor control system measures the intensity and frequency of infrared rays (IR) reflected from the object using the light receiver and adjusts the amount of light based on a histogram created based on this, to measure accurate depth of the object without additional equipment.

According to the present invention, a robot cleaner includes a constraint prevention filter to prevent the robot cleaner from being constrained resulting from a cleaning nozzle being caught by an obstacle. Therefore, the constraint prevention filter may prevent the robot cleaner from being stopped by the obstacle while cleaning or contamination to other cleaning areas resulting from foreign substances adsorbed onto a cleaning nozzle.

In addition, according to the present disclosure, the robot cleaner may control to avoid or climb an obstacle according to types of obstacles and select an optimal driving method based on types of the obstacles. Therefore, the robot cleaner may extend a range of cleaning area and prevent the cleaning nozzle from being caught by the obstacle, thereby improving cleaning efficiency.

In addition, according to the present disclosure, the robot cleaner may store information on types and positions of obstacles and move while avoiding the obstacles based on the stored data to prevent the robot cleaner from being continuously constained by the same obstacle. Therefore, reliability of the operation of the robot cleaner may be enhanced and user satisfaction may be improved.

In addition, according to an example, a depth sensor control system may automatically adjust an amount of light to accurately measure an accurate depth of an object to prevent a phenomenon in which the depths of some areas are not measured based on external light source or reflectance of a target object. Therefore, the depth sensor may accurately measure the depth of the target object, thereby improving reliability of the depth sensor.

In addition, according to an example, the depth sensor control system may control the amount of incident light by performing a function for measuring the infrared intensity of the depth sensor to measure the exact depth of the target object without light-amount controlling components. Therefore, manufacturing cost of the depth sensor may be reduced, thereby improving the profit of the manufacturer.

In addition, according to an example, the depth sensor control system controls the exposure time of the light receiver and the output of the light emitter using a histogram created based on the intensity of infrared light measured by the light receiver, thereby obtaining a fast response time for controlling the amount of light to accurately measure the depth of the object. Therefore, an overall reaction speed of the system using the depth sensor may be increased and the satisfaction of the user using the device may be improved.

Further to the effects described above, specific effects of the present disclosure are described together while describing detailed matters for implementing the present disclosure.

The terms or words used in the present disclosure and claims are not to be construed as limiting the ordinary or dictionary meanings and are to be construed as meaning and concepts corresponding to the technical ide of the present disclosure on the basis of a principle that an inventor can suitably define the concept of a term in order to explain the subject matter that the inventor regards as his disclosure in a best way. Further, embodiments and drawings in the present disclosure are merely a most preferable embodiment, but not represent all technical ideas of the present disclosure, and thus, it is to be understood that various equivalents and modifications which can replace them at a time of filing can be made.

Hereinafter, a robot cleaner according to an embodiment of the present invention is described in detail with reference to <FIG>.

<FIG> is a perspective view showing a robot cleaner according to an embodiment of the present invention.

<FIG> is a plan view showing the robot cleaner in <FIG>. <FIG> is a cross-sectional view showing an operation of the robot cleaner in <FIG>. <FIG> shows components of a constraint prevention filter in <FIG>. <FIG> is a block diagram showing components of the robot cleaner in <FIG>.

Referring to <FIG>, a robot cleaner <NUM> according to an embodiment of the present disclosure includes housings <NUM> and <NUM>, a controller <NUM>, a sensor <NUM>, a driver <NUM>, an agitator <NUM>, a constraint prevention filter portion <NUM>, a memory <NUM>, a display <NUM>, and an interface <NUM>.

The housings <NUM> and <NUM> define appearance of the robot cleaner <NUM>.

For example, the housings <NUM> and <NUM> include a main body <NUM> including a suction motor to generate a suction power and a nozzle <NUM> to sweep dust or foreign substances from the floor to facilitate suction.

The controller <NUM> and the driver <NUM> are disposed in the main body <NUM>, the sensor <NUM> is disposed at one side thereof, and the display <NUM> and the interface <NUM> are each disposed on an upper surface thereof.

Although not clearly shown in the drawing, the main body <NUM> may include a suction inlet <NUM> (see <FIG>) to introduce air suctioned through the nozzle <NUM>, a suction motor (not shown) to generate a suction power, a dust bin (not shown) to separate and store foreign substances of the suctioned air, and a discharge outlet <NUM> to discharge the suctioned air to an outside thereof.

In this case, the suction inlet <NUM> may be defined between the nozzle <NUM> and the main body <NUM> and the discharge outlet <NUM> may be defined on the upper surface of the main body <NUM>.

The nozzle <NUM> corresponds to a portion through which the robot cleaner <NUM> suctions foreign substances. The nozzle <NUM> has a shape protruding from one side of the main body <NUM>. In this case, a protruding direction of the nozzle <NUM> may be referred to as a forward direction with respect to the main body <NUM>. The nozzle <NUM> has an upper surface lower than the upper surface of the main body <NUM>.

For reference, some of the components of the main body <NUM> may be disposed at the nozzle <NUM>.

An agitator <NUM> and a constraint prevention filter portion <NUM> are disposed in the nozzle <NUM>. The agitator <NUM> sweeps or scatters dust or dirt on the floor under the robot cleaner <NUM>. Details of the constraint prevention filter portion <NUM> are described below.

The controller <NUM> controls the operations of all components of the robot cleaner <NUM>.

The controller <NUM> receives the data sensed by the sensor <NUM> and controls an operation of the driver <NUM>, the agitator <NUM>, or the constraint prevention filter portion <NUM> based on the received data.

For example, the controller <NUM> determines the type of obstacle based on the data sensed by the sensor <NUM> and changes a driving method based o a result of determining the type of obstacle. For example, the controller <NUM> may classify the obstacle as an avoiding obstacle or a climbing obstacle.

The avoiding obstacle refers to an obstacle that may interfere with movement of the robot cleaner <NUM> when the robot cleaner <NUM> moves in a moving direction. For example, the avoiding obstacle may include an obstacle having a greater height and an obstacle made of thin fabric. The robot cleaner <NUM> may not move over the obstacle having the greater height and the obstacle made of thin fabric may block movement of the robot cleaner <NUM> in the moving direction thereof or may be rolled into the robot cleaner <NUM> when the robot cleaner <NUM> moves in the moving direction thereof.

The climbing obstacle refers to an obstacle over which the robot cleaner <NUM> may climb. For example, the climbing obstacles may include rigid door frames or wide, heavy carpets.

The controller <NUM> may determine the type of obstacle based on previously stored data.

In addition, for obstacle classification, the controller <NUM> may use a deep learning algorithm to perform self-learning based on the collected data, a logistic regression algorithm, a support vector machine (SVM) algorithm that extends the concept of perceptron, and a convolutional neural network (CNN) algorithm that learns based on randomly initialized parameters.

The CNN algorithm learns randomly initialized parameters of neural network as learning data and outputs a probability corresponding to each of classes (e.g. two classes of climbing obstacle/avoiding obstacle) when an image is input. For example, when the robot cleaner <NUM> encounters an obstacle, the CNN algorithm calculates a probability of an climbing obstacle and a probability of an avoiding obstacle based on the detected obstacle from the image and selects one having high probability among the two probabilites.

For reference, these algorithms are only a few examples that may be used by the controller <NUM>, and the present disclosure is not limited thereto.

The sensor <NUM> is disposed at one side of the main body <NUM> and detects an obstacle positioned in front of the robot cleaner <NUM>. The sensor <NUM> transmits the measured data to the controller <NUM>. The controller <NUM> determines an obstacle based on the data received from the sensor <NUM>.

The sensor <NUM> may include an RGB sensor to measure an image of an obstacle, an ultrasonic sensor, an infrared sensor, a depth sensor to measure a depth of the obstacle, an RGB-D sensor, and the like.

As the sensor <NUM> has a certain measurement range, the sensor <NUM> may be tilted forward, rearward, leftward, and rightward on the main body <NUM> to cover a wide area.

For reference, only one sensor <NUM> is shown in the drawing; however, a plurality of sensors may be disposed on the main body <NUM> or the nozzle <NUM> to detect a forward space, a rearward space, and a side space of the main body <NUM>.

The agitator <NUM> includes a rotating brush to sweep or scatter dust or dirt on the floor under the robot cleaner <NUM>.

The agitator <NUM> is disposed under the main body <NUM> or the nozzle <NUM> to contact a portion of the rotating brush with the floor. The agitator <NUM> may rotate to move the robot cleaner <NUM> forward and the rotation speed thereof may be controlled by the controller <NUM>.

The driver <NUM> generates a driving force to move the robot cleaner <NUM>. Although not clearly shown in the drawings, the driver <NUM> includes a pair of wheels <NUM> disposed under the main body <NUM> and a drive motor (not shown) to generate a driving force for rotating the wheels <NUM>.

The operation of the driver <NUM> is controlled by the controller <NUM>. The controller <NUM> controls the pair of wheels <NUM> to rotate in a same direction for moving the main body <NUM> forward or to rotate the pair of wheels <NUM> in different directions for rotating the main body <NUM>.

The constraint prevention filter portion <NUM> performs a function for blocking entry of the obstacle provided at a position in a moving direction of the robot cleaner <NUM> into the agitator <NUM>.

The constraint prevention filter portion <NUM> includes a constraint prevention filter <NUM>, a rotary shaft <NUM> to couple to the constraint prevention filter <NUM>, and a filter driver <NUM> to control a position of the rotary shaft <NUM>.

The constraint prevention filter <NUM> has a shred shape including a plurality of thin and long strings and may prevent an obstacle of a predetermined size or more from entering the inner side of the main body <NUM>.

In order to accomplish the function, the constraint prevention filters <NUM> may be disposed on the rotary shaft <NUM> at predetermined distances. As shown in <FIG>, the constraint prevention filter <NUM> may have an inwardly concaved and has one end facing outward such that the constraint prevention filter <NUM> has resistance of predetermined magnitude and filters out the obstacles. The constraint prevention filter <NUM> has the shape such that the constraint prevention filter <NUM> filters out the obstacles and the resistance thereof is reduced when the end of prevention filter <NUM> which is shred-shaped contacts the floor.

In this case, a portion of the constraint prevention filter portion <NUM> may protrude to an outside of the nozzle <NUM>.

The constraint prevention filter <NUM> may be made of an elastic material. Therefore, the constraint prevention filter <NUM> moves while blocking the obstacle based on elasticity itself when a light obstacle is provided and bends inward when a heavy obstacle is provided.

The rotary shaft <NUM> of the constraint prevention filter portion <NUM> may be fixed inside the nozzle <NUM> and rotate. The filter driver <NUM> is disposed at one side of the rotary shaft <NUM> to control the position of the rotary shaft <NUM>.

The filter driver <NUM> may rotate the rotary shaft <NUM> to adjust the position of the constraint prevention filter <NUM>.

Although not clearly shown in the drawings, the filter driver <NUM> may include a nozzle sensor (not shown) to measure a magnitude of resistance applied to the constraint prevention filter <NUM>. The controller <NUM> may adjust the position of the constraint prevention filter <NUM> based on data measured by the nozzle sensor (not shown).

In addition, the filter driver <NUM> may include a spring or a drive motor to rotate the rotary shaft <NUM> when resistance having a predetermined magnitude or more is applied to the constraint prevention filter <NUM> and restore the position of the constraint prevention filter <NUM> when the resistance is not applied.

For reference, the matters described above are only example components of the filter driver <NUM> and the configuration of the filter driver <NUM> may be variously modified and implemented.

The memory <NUM> stores a control command code and control data for controlling the robot cleaner <NUM>. In addition, the memory <NUM> stores data measured by the sensor <NUM> while the robot cleaner <NUM> is moving, types of obstacles determined by the controller <NUM>, and position coordinate data of the obstacle.

The memory <NUM> may include at least one of a volatile memory or a nonvolatile memory. In addition, the memory <NUM> may be a nonvolatile medium such as a hard disk (HDD), a solid state disk (SSD), an embedded multi-media card (eMMC), and a universal flash storage (UFS).

The display <NUM> includes a display to indicate an operation state of the robot cleaner <NUM>. For example, the display <NUM> may display information on the remaining amount of the battery, the remaining capacity of the internal dust bin, and an operation mode of the robot cleaner <NUM>.

The interface <NUM> may receive an operation method from a user. In the drawing, the interface <NUM> configured as a button-type interface is illustrated, but the present disclosure is not limited thereto. For example, the interface <NUM> may be replaced with a touch panel provided on the display <NUM>, a microphone to receive a user's voice command, a user gesture recognizing device, and the like.

Additionally, the robot cleaner <NUM> may further include a power supply having a built-in battery for supplying internal power or to receive power from an external device, and a communicator to exchange data with an external device.

<FIG> is a flowchart showing an operation of the robot cleaner in <FIG>.

Referring to <FIG>, for a robot cleaner <NUM> according to an embodiment of the present disclosure, a controller <NUM> determines whether an obstacle is detected in a space in a moving direction of the robot cleaner <NUM> based on data measured by a sensor <NUM> (S <NUM>).

Subsequently, when the obstacle is provided at a position in the moving direction of the robot cleaner <NUM>, the controller <NUM> determines whether the detected obstacle is a distant obstacle far away farther than a reference distance (S120).

Subsequently, when the detected obstacle is placed closer than the reference distance, the controller <NUM> determines whether the obstacle is detected only in front of the constraint prevention filter <NUM> (S122).

If the obstacle is not detected at a position farther than the reference distance and is detected only in front of the constraint prevention filter <NUM>, the obstacle is caught by the constraint prevention filter <NUM> and a height thereof is increased in front of the nozzle <NUM>, which signifies that the robot cleaner <NUM> is constrained by the obstacle.

For example, in the case of fabric, the constraint prevention filter <NUM> may prevent the fabric from entering the agitator <NUM>, and in this process, the fabric is pushed by the nozzle <NUM>, thereby increasing the height thereof.

In this case, as the fabric having the increased height may have greater resistance and apply a load to the robot cleaner <NUM>, the controller <NUM> stores the position information of the obstacle located in front of the nozzle <NUM> (S124) and controls the robot cleaner to move while avoiding the obstacle (S130).

For reference, the fabric was exemplified above, but obstacles such as crumpled paper, rubbers, and mats may also interfere with the movement of the robot cleaner <NUM> if the constraint prevention filter <NUM> is caught by the obstacles such as the crumpled paper, the rubbers, and the mats. Therefore, controller <NUM> stores the position information of the obstacle and controls the robot cleaner to perform the cleaning operation by avoiding the obstacle.

If the detected obstacle is located farther than the reference distance, the controller <NUM> determines the type of the obstacle (S140).

Subsequently, the controller <NUM> determines whether the detected obstacle is an avoiding obstacle (S150).

The avoiding obstacle refers to an obstacle that may interfere with the movement of the robot cleaner <NUM> when the robot cleaner <NUM> moves in the moving direction thereof.

For example, the robot cleaner <NUM> may include a high-height obstacle, an obstacle obstructing the moving direction of the robot cleaner <NUM>, and an obstacle that may be rolled into the robot cleaner <NUM>.

Subsequently, if the obstacle is detected as an avoiding obstacle, the controller <NUM> stores the position information of the corresponding obstacle (S124).

Subsequently, the controller <NUM> controls the robot cleaner <NUM> to move while avoiding the avoiding obstacle (S130).

The controller <NUM> determines whether the detected obstacle is a climbing obstacle (S155). The climbing obstacle refers to an obstacle over which the robot cleaner <NUM> may climb. For example, climbing obstacles may include rigid door frames or wide and heavy carpets.

If the obstacle is detected as a climbing obstacle, the controller <NUM> controls the filter driver <NUM> in order for the constraint prevention filter <NUM> not to be caught by the climbing obstacle and accommodate the constraint prevention filter <NUM> into the nozzle <NUM>.

For reference, the controller <NUM> may measure the resistance applied to the constraint prevention filter <NUM>, and when a resistance equal to or greater than a reference value is applied to the constraint prevention filter <NUM>, the controller <NUM> may control the constraint prevention filter <NUM> to be accommodated in the nozzle <NUM>. When a resistance equal to or less than the reference value is applied to the constraint prevention filter <NUM>, the controller <NUM> may control the robot cleaner <NUM> to move in the moving direction thereof without adjusting the position of the constraint prevention filter <NUM>.

In addition, as the constraint prevention filter <NUM> is made of elastic material, the constraint prevention filter <NUM> mat be naturally accommodated in the nozzle <NUM> when resistance having a magnitude equal to or greater than a predetermined magnitude is applied by a climbing obstacle without additional control of the filter driver <NUM>.

Subsequently, the controller <NUM> controls the driver <NUM> in order for the robot cleaner <NUM> to climb over the climbing obstacle (S160). For example, the controller <NUM> may control the driver <NUM> in order for the robot cleaner <NUM> to easily climb the obstacle because the height of the main body <NUM> is increased.

Subsequently, if an obstacle is not detected, the controller <NUM> normally drives the robot cleaner <NUM> (S170).

That is, as the robot cleaner <NUM> according to the present disclosure is controlled to avoid or climb the obstacle according to the type of obstacle, thereby selecting an optimal driving method according to the type of obstacle.

Therefore, the range of cleaning area of the robot cleaner may be extended and cleaning efficiency thereof may be improved by preventing the cleaning nozzle from being caught by the obstacle.

<FIG> show an operation of a robot cleaner according to an embodiment of the present disclosure.

Referring to <FIG>, when an obstacle E1 is introduced into a robot cleaner <NUM>, an agitator <NUM> may be constrained by the obstacle E1 and the operation thereof may be stopped. In addition, when the agitator <NUM> continuously performs the operation while being constrained by the obstacle E1, a load is applied to the robot cleaner <NUM>, thereby increasing a probability of causing a failure.

To prevent the above issue, the sensor <NUM> detects an obstacle located in an area in a moving direction of the robot cleaner <NUM>, but obstacles E1 having a low height, which cannot be detected by the sensor <NUM>, may be present in the cleaning area.

In this case, for the robot cleaner <NUM> of the present disclosure, the constraint prevention filter <NUM> faces forward and downward the nozzle <NUM> to prevent entry of the obstacle E1, which is not detected by the sensor <NUM>, into the agitator <NUM>.

Therefore, the constraint prevention filter <NUM> may prevent the operation of the robot cleaner <NUM> from being stopped by being caught by the obstacle or contamination on other cleaning areas, resulting from adsorption of foreign substances to the agitator <NUM>, while cleaning.

Referring to <FIG>, resistance having greater magnitude may be applied to the constraint prevention filter <NUM> when the robot cleaner is caught by an obstacle (E2) (e.g., a carpet) that is relatively heavy or attached to the floor among the obstacles not detected by the sensor <NUM>.

In this case, as the constraint prevention filter <NUM> is made of elastic material, the constraint prevention filter <NUM> may be bent inward and accommodated in the nozzle <NUM> based on the resistance caused by the heavy obstacle E2.

The constraint prevention filter portion <NUM> measures the resistance applied to the constraint prevention filter <NUM>, and when the measured resistance is greater than the reference value, the controller <NUM> controls the filter driver <NUM> to accommodate the constraint prevention filter <NUM> in the nozzle <NUM>.

Referring to <FIG>, when the constraint prevention filter <NUM> is caught by the obstacle E3 that is not detected by the sensor <NUM> and is accumulated in front of the nozzle <NUM>, the obstacle E3 having the increased height causes high resistance to apply a load to the robot cleaner <NUM>.

In this case, when the height of the obstacle E3 is increased, the sensor <NUM> may detect the presence of the obstacle E3. The controller <NUM> determines that the obstacle E3 is not detected when the obstacle E3 is positioned in an area far away by a distance equal to or greater than the reference distance, but is suddenly detected when the obstacle E3 is positioned in an area far away by a distance equal to or less than the reference distance.

In this case, the controller <NUM> stores the position information of the obstacle E3 located in front of the nozzle <NUM> and controls the driver <NUM> to avoid the obstacle E3. Therefore, even if the robot cleaner <NUM> encounters the obstacle E3 during a next driving, the robot cleaner <NUM> may move while avoiding the obstacle E3 in advance before a predetermined distance.

That is, the robot cleaner <NUM> of the present disclosure stores the position information of the obstacle E3 and moves while avoiding the obstacle E3 based on the stored data, thereby preventing the robot cleaner <NUM> from being continuously constrained by the same obstacle E3.

Therefore, reliability of the operation of the robot cleaner may be enhanced and user satisfaction may be improved.

Sensing devices to sense distance from a target object include a three-dimensional (3D) camera, a depth sensor, a motion capture sensor, and a laser radar.

The depth sensor uses a time of flight (TOF) method.

The TOF method is a method of measuring a light flight time until light reflected from a target object is received by a sensor after transmitting the light onto the target object. The depth sensor measures a distance from the object by measuring a time period for which the light emitted from the light source returns after being reflected by the object using the above method.

Hereinafter, a depth sensor control system to control an amount of light incident on the depth sensor is described in detail with reference to <FIG>.

<FIG> is a block diagram showing a depth sensor control system according to an embodiment of the present disclosure. <FIG> shows a method of driving the depth sensor control system in <FIG>.

Referring to <FIG> and <FIG>, the depth sensor control system <NUM> according to an embodiment of the present disclosure includes a light emitter <NUM>, a light receiver <NUM>, and a controller <NUM>.

Specifically, the light emitter <NUM> transmits light to an object TG.

In this case, the light emitter <NUM> may transmit the light in an infrared ray (IR) or near infrared ray region to the object TG.

For reference, this is only an example, and the light emitter <NUM> may transmit light of a different wavelength (e.g., laser, ultrahigh frequency, radio frequency (RF) signal, ultraviolet ray (UV). Hereinafter, the light emitter <NUM> to transmit the IR is described as an example.

An intensity and wavelength of the transmitted light may be adjusted based on a magnitude of driving voltage or power applied to the light emitter <NUM>. An output (Ps) of the light emitter <NUM> is controlled by the sensor controller <NUM>.

Light transmitted by the light emitter <NUM> may be reflected by the surface of the object TG, for example, by skin or clothing. A phase difference between the light transmitted by the light emitter <NUM> and the light reflected from the object TG may occur based on a distance between the light emitter <NUM> and the object TG.

The light receiver <NUM> senses light (e.g., IR) that is transmitted by the light emitter <NUM> and reflected from the object TG.

The light receiver <NUM> includes a lens <NUM>, an optical shutter <NUM>, and an image sensor <NUM>. However, this is only an example, and the light receiver <NUM> may be implemented by omitting some components or adding additional components.

For example, the lens <NUM> collects the IR reflected from the object TG.

The optical shutter <NUM> is positioned on a path through which the light reflected from the object TG travels and may change the IR intensity by adjusting an exposure time (Texp) of the reflected light.

In addition, the optical shutter <NUM> may modulate the wavelength of the light reflected from the object TG by adjusting the transmittance of the light reflected from the object TG.

In addition, the light emitted from the light emitter <NUM> may be modulated by applying a specific frequency and the optical shutter <NUM> may drive at a same frequency as the specific frequency. A shape of the reflected light modulated by the optical shutter <NUM> may vary depending on a phase of light incident on the optical shutter <NUM>.

<FIG> shows a graph corresponding to a change in intensity with respect to time of light (Illuminating IR profile; hereinafter ILIR) transmitted by a light emitter <NUM> and a graph corresponding to a change in intensity with respect to time of a light reflected from an object TG (reflecting IP profile; hereinafter; RFIR). <FIG> also shows a change in transmittance of the optical shutter <NUM> with respect to time.

The light emitter <NUM> may sequentially transmit the light ILIR to the object TG. In this case, a plurality of lights ILIR output from the light emitter <NUM> may be transmitted to the object TG with an idle time and may be transmitted with different phases.

For example, when the light emitter <NUM> transmits four lights ILIR to the object TG, the transmitted lights ILIR may have phases of <NUM> degrees, <NUM> degrees, <NUM> degrees, and <NUM> degrees, respectively.

Subsequently, the reflected lights RFIR reflected from the object TG may independently pass through the lens <NUM> and the optical shutter <NUM> and be incident on the image sensor <NUM>.

In this case, the transmittance of the optical shutter <NUM> may change over time. In addition, the transmittance of the optical shutter <NUM> may change according to a level of a bias voltage applied to the optical shutter <NUM> in a specific wavelength region. Therefore, a waveform may be modulated as the reflected lights RFIR pass through the optical shutter <NUM>.

The modulated waveform of the reflected lights RFIR may be changed based on the phase of the reflected lights RFIR and changes in transmittance of the optical shutter <NUM> over time.

Subsequently, the image sensor <NUM> may capture the reflected lights RFIR modulated by the optical shutter <NUM> to determine a phase difference between the reflected lights RFIR and the transmitted lights ILIR.

In this case, the image sensor <NUM> senses the intensity and the phase of light that has been condensed by the lens <NUM> and passed through the optical shutter <NUM>. The image sensor <NUM> may include a complementary metal oxide semiconductor (CMOS) sensor or a charge coupled device (CCD).

The controller <NUM> may generate depth information of the object TG based on the intensity and the phase of light sensed by the image sensor <NUM>.

The controller <NUM> includes a sensor controller <NUM> and a depth calculator <NUM>.

For example, the sensor controller <NUM> may adjust an exposure time (Texp) of the light receiver <NUM> or the output (Ps) of the light emitter <NUM> based on the measured intensity of light (i.e., an amount of light) reflected from the object TG.

When the intensity of light received by the light receiver <NUM> is not within an appropriate range, depth of the object TG may not be properly measured.

To correct this, the sensor controller <NUM> decreases the exposure time (Texp) of the light receiver <NUM> or the output (Ps) of the light emitter <NUM> if an excessive amount of light is received.

If an insufficient amount of light is received, the sensor controller <NUM> increases the exposure time (Texp) of the light receiver <NUM> or the output (Ps) of the light emitter <NUM>.

A detailed description thereof is described below.

Meanwhile, the depth calculator <NUM> calculates a phase difference of light measured after being reflected from the object TG and generates pixel depth information of the object TG based on the calculated phase difference of light.

That is, when the depth of a partial area of the object TG is not measured because an appropriate amount of light is not received due to the external light source or the reflectance of the object TG, the controller <NUM> may automatically adjust the intensity of light to measure accurate depth.

For reference, the depth sensor control system <NUM> of the present disclosure may include a display <NUM> to visually display depth information of the object TG to a user. However, this is only an example, and the present disclosure is not limited thereto.

Further, although not clearly shown in the drawings, the depth sensor control system <NUM> may transmit an operation command to the controller <NUM> using an interface (not shown).

For example, the interface (not shown) may include a touch panel disposed on the display <NUM>, a microphone to receive a user's voice command, a recognizing device to recognize a user's gesture, and the like.

<FIG> is a graph showing a histogram used by the sensor controller in <FIG>.

Referring to <FIG>, a sensor controller <NUM> uses a histogram generated based on an intensity of received light to control an exposure time (Texp) of a light receiver <NUM> and an output (Ps) of an light emitter <NUM>.

Specifically, the sensor controller <NUM> generates the histogram showing the intensity of IR incident on the light receiver <NUM>.

An X-axis of the histogram represents an IR intensity and an Y-axis of the histogram represents a number of pixels. For reference, ranges of the X-axis and Y-axis in the histogram may be variously modified and implemented.

A range (R) of an appropriate intensity (hereinafter; an appropriate range (R)) of the IR is set in the histogram to accurately measure the depth.

The appropriate range (R) in the histogram is determined to be an area with a stable depth through a previously executed experiment and the appropriate range (R) information of the histogram may be stored the memory of the controller <NUM> in advance to be used.

For example, the appropriate range (R) of the histogram may be set to have the IR of equal to or greater than <NUM> and equal to or less than <NUM>, but the present disclosure is not limited thereto.

In order for the depth calculator <NUM> to accurately measure the depth of the object TG, a ratio of the light intensity in the appropriate range (R) in the histogram may be provided within a predetermined reference ratio range.

In this case, the reference ratio range may be set based on a look-up table that has been experimentally and previously generated and stored. The look-up table may be stored in advance in the memory of the controller <NUM> and used by the sensor controller <NUM>.

If the ratio of the light intensity within to the appropriate range (R) to the intensity of the total light does not fall within the reference ratio range, the sensor controller <NUM> adjusts the exposure time (Texp) of the light receiver <NUM>.

If the ratio of the light intensity within the appropriate range (R) is greater than an upper limit of the reference ratio range, the sensor controller <NUM> reduces the exposure time (Texp) of the light receiver <NUM>, and when the ratio of the light intensity within the appropriate range (R) is less than a lower limit of the reference ratio range, the sensor controller <NUM> increase the exposure time (Texp) of the light receiver <NUM>.

For example, assuming that the reference ratio range is <NUM>% to <NUM>%, when the ratio of the light intensity within the appropriate range (R) is <NUM>%, the sensor controller <NUM> may increase the exposure time (Texp) of the light receiver <NUM>. If the ratio of the intensity of light within the appropriate range (R) is <NUM>%, the sensor controller <NUM> decreases the exposure time (Texp) of the light receiver <NUM>.

For reference, in another embodiment of the present disclosure, only a specific reference value may exist in the reference ratio range.

In this case, the sensor controller <NUM> adjusts the exposure time (Texp) of the light receiver <NUM> if the ratio of the intensity of light in the appropriate range R to the intensity of the total light is less than the reference ratio range.

If the reference ratio range is <NUM> percent and the ratio to the intensity of light belonging to the appropriate range (R) is <NUM> percent, the sensor controller <NUM> increases the exposure time (Texp) of the light receiver <NUM>.

The sensor controller <NUM> may adjust the exposure time (Texp) of the light receiver <NUM> only within an appropriate exposure time range.

The appropriate exposure time range refers to an exposure time range in which the depth sensor control system <NUM> may obtain an appropriate response speed and depth accuracy.

That is, the exposure time (Texp) of the light receiver <NUM> may be adjusted only between an upper boundary value (T1) and a lower boundary value (T2) of the appropriate exposure time range.

If the exposure time (Texp) of the light receiver <NUM> is adjusted to correspond to the upper boundary value (T1) or the lower boundary value (T2), the sensor controller <NUM> does not adjust the exposure time (Texp), but adjust the output (Ps) of the light emitter <NUM>.

Hereinafter, a method of adjusting the output (Ps) of the light emitter <NUM>, rather than the exposure time (Texp), to obtain an appropriate amount of light by the sensor controller <NUM> is described in detail.

<FIG> is a flowchart showing an operation of the depth sensor control system in <FIG>.

Referring to <FIG>, for the operation of the depth sensor control system according to an exemplary embodiment of the present disclosure, a light emitter <NUM> emits IR to an object TG (S110). The emitted IR are reflected from the object TG and received by a light receiver <NUM>.

Subsequently, the light receiver <NUM> detects the IR reflected from the object TG (S120). In this case, the intensity of IR received by the light receiver <NUM> may vary depending on reflectance of an external light source or the object TG.

Subsequently, a sensor controller <NUM> generates an infrared histogram based on the intensity of IR received by the light receiver <NUM> (S130). In this case, an appropriate range (R) of IR is set in the histogram for accurately measuring depth The appropriate range (R) in the histogram is determined to be an area where the object has a most suitable depth through a previously executed experiment and may be stored in the memory of the controller <NUM> in advance to be used.

Subsequently, the sensor controller <NUM> calculates a ratio of an intensity of IR within the appropriate range (R) to the intensity of total IR (S140).

Subsequently, the sensor controller <NUM> derives a reference ratio range for obtaining reliability of depth measurement based on a look-up table that has been experimentally and previously generated and stored.

Subsequently, the sensor controller <NUM> determines whether the calculated ratio is within the reference ratio range.

If the calculated ratio falls within the reference ratio range, the depth calculator <NUM> calculates the depth of each pixel based on the data sensed by the light receiver <NUM> (S190).

If the calculated ratio is not within the reference ratio range, the sensor controller <NUM> adjusts the exposure time (Texp) of the light receiver <NUM> (S160).

If the ratio of the intensity of infrared rays belonging to the appropriate range (R) is greater than the upper limit of the reference ratio range, the sensor controller <NUM> reduces the exposure time (Texp) of the light receiver <NUM>. If the ratio of the intensity of infrared rays belonging to the appropriate range (R) is less than a lower limit of the reference ration range, the sensor controller <NUM> increases the exposure time (Texp) of the light receiver <NUM>.

For reference, in another embodiment of the present disclosure, a specific reference value may only exist in the reference ratio range. In this case, if the ratio of the intensity of light in the appropriate range R to the intensity of the total light is less than the reference ratio range, the sensor controller <NUM> increases the exposure time (Texp) of the light receiver <NUM>.

For example, the sensor controller <NUM> may adjust the exposure time (Texp) of the light receiver <NUM> only within a range of an appropriate exposure time.

Subsequently, the sensor controller <NUM> determines whether the adjusted exposure time (Texp) falls within the appropriate exposure time range (S170). The appropriate exposure time range refers to an exposure time range in which the depth sensor control system <NUM> may obtain an appropriate response speed and depth accuracy.

That is, the exposure time (Texp) of the light receiver <NUM> may be adjusted only between the upper boundary value (T1) and the lower boundary value (T2) of the appropriate exposure time range.

If the adjusted exposure time (Texp) does not fall within in the appropriate exposure time range, the sensor controller <NUM> adjusts the output (Ps) of the light emitter <NUM> (S180).

If the adjusted exposure time (Texp) corresponds to the upper boundary value of the appropriate exposure time range, the sensor controller <NUM> increases the output of the light emitter <NUM>. If the adjusted exposure time (Texp) corresponds to the lower boundary value of the appropriate exposure time range, the sensor controller <NUM> reduces the output of the light emitter <NUM>.

Subsequently, the sensor controller <NUM> repeatedly performs S110 to S170 described above.

Even if the adjusted exposure time (Texp) falls within the appropriate exposure time range, the sensor controller <NUM> repeatedly performs S110 to S150 described above.

Therefore, the sensor controller <NUM> may adjust the exposure time (Texp) of the light receiver <NUM> and the output (Ps) of the light emitter <NUM> using the histogram generated based on the IR intensity measured by the light receiver <NUM> to obtain a fast response time for responding to amount of light adjusted to accurately measure the depth of the object.

Therefore, the overall reaction speed of the depth sensor control system <NUM> using the depth sensor may be increased and the satisfaction of the user using the device may be improved.

In addition, the depth sensor control system <NUM> according to the present disclosure may adjust the amount of incident light by performing the function for measuring the IR intensity, by the depth sensor, thereby measuring the accurate depth of the object without additional light-amount control components. Therefore, the manufacturing cost of the depth sensor may be reduced and the profit of the manufacturer may be increased.

Meanwhile, reference numerals used in <FIG> are applied only to <FIG>.

Claim 1:
A robot cleaner, comprising:
a housing (<NUM>, <NUM>) comprising a suction inlet (<NUM>) configured to suction foreign substances, a suction motor configured to generate a suction force, and a discharge outlet (<NUM>) configured to discharge the suctioned air to an outside thereof;
a driver (<NUM>) configured to move the robot cleaner;
an agitator (<NUM>) disposed under the housing (<NUM>, <NUM>) and configured to move the foreign substances located on the floor to the suction inlet (<NUM>) by performing rotation;
a constraint prevention filter portion (<NUM>) configured to perform a function for blocking entry of an obstacle provided at a position in a moving direction of the robot cleaner (<NUM>) into the agitator (<NUM>), the constraint prevention filter portion (<NUM>) comprising a constraint prevention filter (<NUM>), a rotary shaft (<NUM>) to couple to the constraint prevention filter (<NUM>), and a filter driver (<NUM>) to control a position of the rotary shaft (<NUM>);
a sensor (<NUM>) disposed on the housing (<NUM>, <NUM>) and configured to detect an obstacle positioned in the first direction; and
a controller (<NUM>) configured to control the operation of each of the driver (<NUM>) and the filter driver (<NUM>) based on types of obstacles detected by the sensor (<NUM>),
characterized in that the constraint prevention filter (<NUM>) has a shred shape including a plurality of thin and long strings and prevents the obstacle of a predetermined size or more from entering the inner side of the main housing (<NUM>), and
in that the constraint prevention filter (<NUM>) is positioned to face the moving direction with respect to the housing (<NUM>, <NUM>).