KR20090019479A - Method for sensing an obstacle of robot cleaning apparatus and robot cleaning apparatus adapted to the same - Google Patents

Abstract

An obstruction detecting method of a robot cleaner using an infrared sensor and a robot cleaner suitable for the same are provided to grasp distance between the robot cleaner and obstacle regardless of the brightness of obstacle. A robot cleaner detecting distance between the robot cleaner and obstacle by using an infrared sensor comprises an emitting part(810) outputting an infra-red signal in order to sense obstacle, a sensor(820) receiving the infra-red signal reflected from the obstacle, a controller(830) outputting a control signal for controlling operation of the robot cleaner, grasping distance from the obstacle based on the point of time when intensity of the received infra-red signal is the maximum value and a driving part(840) receiving the control signal to operate the robot cleaner.

Description

Method for sensing an obstacle of robot cleaning apparatus and robot cleaning apparatus adapted to the same}

The present invention relates to a robot cleaner, and more particularly, to an obstacle detecting method of a robot cleaner and a robot cleaner suitable for detecting the distance between the robot cleaner and the obstacle, regardless of the brightness of the obstacle.

The robot cleaner is a device that removes foreign substances such as dust present on the floor while automatically driving the cleaning area by itself without a user's operation. Such a robot cleaner is designed to perform a cleaning operation while driving a predetermined cleaning path or an optimal cleaning path according to a built-in program.

On the other hand, when the robot cleaner is cleaning, when obstacles such as furniture or walls exist in the progress path, or lowlands such as a living room floor or cliff lower than the flat surface, normal progress is difficult, so to avoid obstacles or lowlands. In order to change the progress path. This is performed by various sensors mounted on the main body and a controller for controlling the operation according to the signals received by the sensors.

The sensor is divided into types according to the method used, and there are largely a method using a PSD sensor, a method using an ultrasonic sensor, and a method using an infrared sensor.

The PSD sensor is a method of measuring a distance to an obstacle using an angle of reflected light, and has a problem of being expensive and having a slow response speed. The method using the ultrasonic sensor is a method of measuring the distance to the obstacle by using the speed of the ultrasonic waves propagating in the air, and there is a problem that an expensive phenomenon occurs. Therefore, in consideration of cost and response speed, a method using an infrared sensor is preferable.

On the other hand, the detection of the obstacle is made by the obstacle detection sensor installed in the front end of the robot cleaner, the floor is detected by the floor detection sensor installed in the lower end of the robot cleaner.

In particular, the infrared sensor for obstacle detection consists of a set of light emitting elements and light receiving elements facing each other at a specific angle, and the controller includes a robot cleaner and an obstacle according to the amount of infrared light emitted from the light emitting elements is reflected from the obstacle and received by the light receiving element. Detects the distance to and controls the action accordingly. This has the advantage that the configuration is simple and the method of use is simple.

However, the conventional robot cleaner has a problem of performing incorrect control by determining the distance to the obstacle based on the intensity of the infrared signal reflected from the obstacle without considering the brightness of the obstacle itself. That is, the conventional method has a problem that does not take into account the fact that the amount of the infrared signal is received when the brightness of the obstacle is different even if the same distance.

In order to solve the above problems, it may be possible to search for a database of the amount of the infrared signal reflected according to the distance for each brightness and generate a profile, but this method increases the area of hardware, There is a problem that the operation time is too long and not suitable. Therefore, there is a need for a method capable of accurately determining the distance from the obstacle regardless of the brightness of the obstacle.

The present invention has been made in an effort to provide a method for detecting an obstacle of a robot cleaner and a robot cleaner suitable for detecting the distance between the obstacle and the robot cleaner regardless of the brightness of the obstacle.

Obstacle detection method of the robot cleaner according to an embodiment of the present invention for solving the technical problem,

A method of sensing a distance from an obstacle using an infrared sensor provided in the robot cleaner, the method comprising: detecting a time point when the intensity of the received infrared signal reaches a maximum value; Determining a distance of the control panel and controlling the operation of the robot cleaner accordingly.

Preferably, the step of detecting the time when the maximum value is detected through the amount of change in the slope of the intensity of the infrared signal.

Preferably, the detecting of the time point at which the maximum value is reached is based on the time point at which the change amount of the slope becomes zero.

Preferably, in the controlling of the operation of the robot cleaner, when the time at which the maximum value is reached reaches the maximum value, the robot cleaner is further moved by a predetermined distance, and then the movement direction thereof is changed.

Preferably, the step of controlling the operation of the robot cleaner moves the robot cleaner according to the proximity distance to the obstacle set by the user.

Preferably, the step of controlling the operation of the robot cleaner, setting the intensity of the infrared signal, and if the intensity of the received infrared signal is reduced by the intensity of the set infrared signal from the maximum value, the robot Control the operation of the cleaner.

Robot cleaner according to an embodiment of the present invention for solving the technical problem,

A robot cleaner for sensing a distance from an obstacle using an infrared sensor provided therein, the robot cleaner for outputting an infrared signal for detecting the obstacle, a detector for receiving an infrared signal reflected from the obstacle, and the reception unit. A control unit for detecting a time point when the intensity of the infrared signal is maximized, determining a distance to the obstacle based on the detected time point, and outputting a control signal for controlling the operation of the robot cleaner accordingly; Characterized in that the drive unit for receiving the control signal to operate the robot cleaner.

Preferably, the detector outputs a voltage corresponding to the magnitude of the received infrared signal to the controller.

Preferably, the controller detects the maximum value based on a time point when the amount of change in the slope of the intensity of the infrared signal becomes zero.

Preferably, the controller calculates a difference between the obstacle proximity distance set by the user and the distance at the point of time when the maximum value is reached, and stores a voltage corresponding to the distance in a memory provided therein.

Preferably, the controller changes the moving direction of the robot cleaner when the magnitude of the voltage received from the detector corresponds to a difference between the magnitude of the voltage corresponding to the maximum value and the magnitude of the voltage stored in the memory. .

Preferably, the controller calculates the difference between the obstacle proximity distance set by the user and the distance at the point of time when the maximum value is reached, and stores the distance in a memory provided therein.

Preferably, the controller changes the moving direction of the robot cleaner when the moving distance after the point of time when the maximum value is reached corresponds to the moving distance stored in the memory.

Due to the configuration as described above, in determining whether there is an obstacle in the front, since it is not determined only based on the intensity of the received infrared signal, there is an effect that it is difficult to determine the exact distance from the obstacle.

In addition, since it is determined whether to control the robot cleaner operation on the basis of the time when the intensity of the infrared signal reaches the maximum value, it is less likely to be influenced by other factors, and thus, it is possible to perform relatively stable control.

In order to fully understand the present invention, the operational advantages of the present invention, and the objects attained by the practice of the present invention, reference should be made to the accompanying drawings which illustrate preferred embodiments of the present invention and the contents described in the drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, if it is determined that the detailed description of the related well-known configuration or function may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

1 is a view showing the configuration of a general robot cleaner.

Referring to FIG. 1, the robot cleaner includes light emitting devices and light receiving devices for obstacle detection. The light emitting element outputs an infrared signal to the front, and the light receiving element receives an infrared signal reflected from an obstacle. In consideration of an efficient aspect, the robot cleaner preferably has four light emitting elements and five light receiving elements.

When the distance between the robot cleaner and the obstacle is within a predetermined range, infrared signals emitted from the light emitting device can be efficiently received by the light receiving device. The driving and operation of the robot cleaner is controlled by the controller, and the controller determines the distance to the obstacle based on the strength of the received infrared signal.

When the intensity of the received infrared signal is equal to or greater than a predetermined value, the controller determines that the distance to the obstacle is close, and changes the running direction of the robot cleaner. This allows the robot cleaner to move without colliding with obstacles such as furniture or walls. The infrared reception process is repeatedly performed while the robot cleaner is moving.

2 is a flowchart illustrating a conventional obstacle detection and control method.

An infrared signal for detecting an obstacle is output using a light emitting device (310). The light emitting device is a front end of the robot cleaner, and is a kind of sensor for detecting an obstacle located in front of the driving direction. When there are a plurality of light emitting elements, step 310 is performed independently and repeatedly for each light emitting element.

The infrared signal reflected from the obstacle is received using the light receiving element (320). The light receiving element may be adjacent to the light emitting element, and may include a plurality of unit light emitting elements that are deflected at a predetermined angle. When there are a plurality of light receiving elements, step 320 is performed independently and repeatedly for each light receiving element.

It is determined whether the intensity of the infrared signal received through the light receiving element is greater than or equal to a predetermined value (230). The predetermined value may be set in the robot cleaner manufacturing process and is generally a reference value for preventing the robot cleaner from colliding with an obstacle and being damaged. However, if the predetermined value is set too small, effective cleaning cannot be performed on the floor of furniture or walls, so it is preferable to set the value in consideration of this.

When the intensity of the infrared signal received through the light receiving element is greater than or equal to a predetermined value, the robot cleaner stops progressing and then moves in a direction different from the previous movement direction (240). In general, since the intensity of the infrared signal reflected and incident on the object increases as the object gets closer, when the intensity of the infrared signal is greater than or equal to a predetermined value, the moving direction of the robot cleaner is changed to prevent a collision.

As described above, the obstacle detecting and controlling method of the conventional robot cleaner determines whether the intensity of the infrared signal reflected and received by the object is greater than or equal to a predetermined value, and performs control accordingly. However, the related art has a problem in that control is performed without considering that the intensity of the received infrared signal may vary depending on the brightness of the object even if a specific object is at the same distance.

3 is a profile illustrating a difference between infrared signals according to brightness of an object.

Referring to FIG. 3, profiles for three colors with different brightness are shown. Here, the horizontal axis represents the distance from the obstacle, and the vertical axis represents the intensity of the ultraviolet signal. In general, white has a brightness of 10, black has a brightness of 0, and gray has a brightness between 0 and 10. In particular, the greater the brightness, the greater the reflectance of the infrared signal, thereby increasing the intensity of the received infrared signal.

Specifically, ⅰ) and the object when the white is the intensity of the infrared signal received by the distance L _max of the object IR _max1, ⅱ) if the object is gray is the intensity of the infrared signal received by the distance L _max of the object IR _max2 , i) When the object is black, the intensity of the infrared signal received at the distance L _max from the object is IR _max3 . Where IR _max1 > IR _max2 > _Satisfies the relationship of IR _max3 .

The present invention uses a method of detecting a distance from an object based on the point of time when the intensity of the infrared signal is maximum, rather than a method of detecting a distance between the robot cleaner and the object based on the intensity of the infrared signal, as in the conventional method. . That is, the control is performed by focusing on the fact that the distance at which the intensity of the received infrared signal is maximized is always constant regardless of the intensity of the object.

4 is a flowchart illustrating a method for detecting and controlling an obstacle according to an embodiment of the present invention.

An infrared signal for obstacle detection is output using a light emitting device (410). The light emitting device may be disposed at a front end of the robot cleaner and may include a plurality of unit light emitting devices that are deflected at a predetermined angle. When there are a plurality of light emitting elements, step 410 is performed independently and repeatedly for each light emitting element.

The infrared signal reflected from the obstacle is received using the light receiving element (420). The light receiving element is located adjacent to the light emitting element, and is a kind of sensor for detecting an obstacle located in front of the driving direction. When there are a plurality of light receiving elements, step 420 is performed independently and repeatedly for each light emitting element.

It is determined whether the intensity of the infrared signal received through the light receiving element reaches a maximum value (430). Referring again to FIG. 3, although the distance is the same, the intensity of the received infrared signal varies depending on the brightness of the object, but the distance when the intensity of the infrared signal reaches its maximum is constant regardless of the brightness of the object. It can be seen.

Therefore, by determining whether the intensity of the infrared signal reaches the maximum value, and controlling the robot cleaner through this, there is an advantage that it is possible to perform accurate control regardless of the brightness of the object. That is, the maximum value of the infrared signal can be calculated through a change amount of the infrared ray slope value as described below.

After reaching the maximum value, the distance is further moved (440). This may vary according to the user's setting, and if necessary, the moving direction may be changed based on the point of time when the maximum value is reached. When the maximum value is reached, the moving direction is changed after a predetermined distance in the previous traveling direction or the opposite direction, and the moving direction is changed (450). The moving direction may be left or right direction.

5 is a flowchart specifically illustrating step 430 of FIG. 4.

The intensity of the received infrared signal is calculated (510). This may be calculated through the magnitude of the converted voltage after converting the intensity of the infrared signal input to the light receiving element to a corresponding voltage. The intensity of the infrared signal changes according to the distance between the robot cleaner and the obstacle, which causes the magnitude of the voltage to change. The step 510 is continuously performed while the robot cleaner is traveling, in particular by a controller provided inside the robot cleaner.

The slope of the intensity of the infrared signal is calculated (520). The slope has a value of (+) when the intensity of the infrared signal increases, and has a value of (−) when the intensity of the infrared signal decreases. In general, when the slope is positive, the distance from the object is getting closer, and when the slope is negative, the distance from the object is getting closer. However, if the distance to the object approaches beyond the threshold, the slope may be negative. The threshold represents the point where the distance is L _max in FIG. 3.

It is determined whether the slope of the intensity of the infrared signal is equal to or less than 530. As described above, in principle, when the tilt is positive, the distance between the robot cleaner and the object is generally closer, but as the distance is approached beyond the threshold, the amount of reflection reflected from the object is reduced and the tilt ( -) If the slope is zero, it indicates that the intensity of the infrared signal has reached the maximum value.

6 is a profile for explaining a robot cleaner control method according to the present invention.

Referring to FIG. 6, profiles for three colors with different brightness are shown. Here, the horizontal axis represents the distance from the obstacle, and the vertical axis represents the intensity of the ultraviolet signal. However, is at the outside relative to the distance (L _max) is the intensity of UV light signal is maximized by a first distance (△ L ₁₎ and second distance (△ L ₂₎ street 6 Fig. 3 differs from The intensity of the ultraviolet signal is shown.

As described above, the present invention is characterized by controlling the operation of the robot cleaner on the basis of the point of time when the intensity of the ultraviolet signal becomes the maximum regardless of the brightness of the object. In addition, when the intensity of the ultraviolet signal reaches the maximum value, the controller sets a predetermined margin based on this, and controls the operation of the robot cleaner when it is out of the margin range. The margin is shown as ΔL ₁ and ΔL ₂ in FIG. 6.

For example, assume that the distance L _max at which the intensity of the ultraviolet signal becomes the maximum is 30 mm. If the set distance to the object for rotation is 25mm, ΔL ₁ may be 5mm. In addition, when the set distance from the object for rotation is 35mm, ΔL ₂ may be 6mm. This may vary according to a user's setting. In particular, when the sizes of ΔL ₁ and ΔL ₂ are small, the relationship between ΔIR ≒ ΔIR ₁ ≒ ΔIR ₂ ≒ ΔIR ₃ is established.

7 is a flowchart illustrating a method for detecting and controlling an obstacle according to another exemplary embodiment of the present invention.

In operation 710, the proximity distance L_set between the robot cleaner and the obstacle is set. That is, the proximity distance L_set relates to a time point of changing the moving direction so as not to collide with the obstacle. Step 710 may be set directly by a user or set in a particular mode. The proximity distance L_set may be larger or smaller than the distance L _max at which the intensity of the infrared signal becomes the maximum value.

ΔIR is calculated (720). ΔIR represents a change from the maximum of the infrared signal. As described above, when ΔL ₁ and ΔL ₂ are small regardless of the brightness of the object, the relationship of ΔIR 의 ΔIR ₁ ≒ ΔIR ₂ ΔΔ ₃ is established. Therefore, the distance L _max between the robot cleaner and the obstacle when the infrared signal reaches the maximum value IR _max is calculated in advance, and ΔIR representing the difference between the distance L _max and the proximity distance L_set is calculated. Calculate and save. The distance L _max is a distance calculated in advance by a statistical method.

An infrared signal for obstacle detection is output using a light emitting device (730). Thereafter, the infrared signal reflected from the obstacle is received using the light receiving element (740). When there are a plurality of light emitting elements or light receiving elements, steps 730 and 740 are performed independently and repeatedly for each light emitting element and light receiving element.

In operation 750, it is determined whether the intensity of the infrared signal received through the light receiving element reaches a maximum value. Depending on the brightness of the object, the maximum value IR _max may vary, but regardless of the brightness, the profiles of the UV intensity have all inflection points of zero slope. Therefore, determining whether the maximum value IR _max has been reached is determining whether the inflection point has been reached.

If the maximum value is reached, the predetermined distance is further moved (760). The predetermined distance represents a distance moved in the forward direction or the backward direction from the distance L _max that becomes the maximum value IR _max of the infrared intensity. Thus, the predetermined distance may be in a positive or negative direction with respect to the previous moving direction of the robot cleaner. The step 760 may be performed to move in mm by fine adjustment of the controller.

It is determined whether ΔIR has been reached (770). That is, it is determined whether the intensity of the infrared signal is reduced by ΔIR from the maximum value IR _max . This is the same as determining whether the set proximity distance L_set has been reached. Referring to FIG. 6, when the color of the object is white, it is determined whether the intensity of the ultraviolet signal reaches (IR _{max1 -ΔIR 1} ). When it reaches, it changes the moving direction of the robot cleaner so as not to collide with the obstacle (780).

8 is a view showing a robot cleaner according to an embodiment of the present invention.

Referring to FIG. 8, the robot cleaner according to the present invention includes a radiator 810, a detector 820, a controller 830, and a driver 840. The radiator 810 includes a light emitting device, and generates an infrared signal to emit an infrared signal in the same direction as the moving direction of the robot cleaner. The detector 820 includes a light receiving element, receives an infrared signal reflected from an obstacle, converts the signal into an electrical signal, and transmits the converted signal to the controller 840.

The controller 830 controls the operation of the radiator 810 and receives a voltage corresponding to the intensity of the infrared signal received from the detector 820. The controller 830 calculates an amount of change in time, that is, a slope, of the input voltage at each moment, and extracts an infrared ray intensity when the slope becomes zero. The extracted maximum value may be stored in the first memory of the controller 830. The controller 830 changes the moving direction by controlling the operation of the driving unit 840 based on the extracted maximum value.

In addition, when the proximity distance is set by the user, the controller 830 calculates a difference between the set proximity distance and the distance at which the infrared intensity becomes maximum, and the voltage corresponding to the distance is stored in the controller 830. Stored in the provided second memory. When the magnitude of the received voltage decreases by the magnitude stored in the second memory, the controller 830 changes the moving direction by controlling the operation of the driving unit 840. The magnitude of the voltage stored in the memory represents the difference between the intensity of the infrared signal at close range and the intensity of the infrared signal at maximum.

In addition, when the proximity distance is set by the user, the controller 830 calculates a difference between the set proximity distance and the distance at the point of time when the infrared intensity becomes maximum, and the controller 830 stores the distance within the controller 830. 3 Can be stored in memory. If the robot cleaner further moves by the distance stored in the third memory, the controller 830 controls the operation of the driving unit 840 to change the moving direction. The movement amount of the distance may be calculated by a traveling distance calculating device that detects the number of revolutions of the main wheel and calculates the traveling distance.

9 is a view showing the operation of the robot cleaner according to an embodiment of the present invention.

Referring to FIG. 9, a diagram illustrating a change in a moving direction according to a distance between a robot cleaner and an obstacle is illustrated. The robot cleaner proceeds by the distance L _max at which the infrared signal reaches the maximum value, and then changes the moving direction when the robot cleaner reaches the set proximity distance L _max -ΔL. That is, it is determined whether to rotate based on the maximum value L _max of the infrared intensity appearing at a constant distance from the object regardless of the brightness of the object.

The best embodiment has been disclosed in the drawings and specification. Although specific terms have been used herein, they are used only for the purpose of describing the present invention and are not used to limit the scope of the present invention as defined in the meaning or claims.

Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

1 is a view showing the configuration of a general robot cleaner.

2 is a flowchart illustrating a conventional obstacle detection and control method.

3 is a profile illustrating a difference between infrared signals according to brightness of an object.

4 is a flowchart illustrating a method for detecting and controlling an obstacle according to an embodiment of the present invention.

5 is a flowchart specifically illustrating step 430 of FIG. 4.

6 is a profile for explaining a robot cleaner control method according to the present invention.

7 is a flowchart illustrating a method for detecting and controlling an obstacle according to another exemplary embodiment of the present invention.

8 is a view showing a robot cleaner according to an embodiment of the present invention.

9 is a view showing the operation of the robot cleaner according to an embodiment of the present invention.

Claims (13)

In the method for detecting the distance to the obstacle using an infrared sensor provided inside the robot cleaner, Detecting a time point when the intensity of the received infrared signal reaches a maximum value; And Determining a distance to the obstacle based on the detected time point, and controlling the operation of the robot cleaner accordingly. The method of claim 1, wherein the detecting of the time point of reaching the maximum value comprises: Obstacle detection method of a robot cleaner, characterized in that the sensing through the amount of change in the slope of the intensity of the infrared signal. The method of claim 2, wherein the detecting of the time point of reaching the maximum value comprises: Obstacle detection method of the robot cleaner, characterized in that on the basis of the time when the change amount of the slope becomes zero. The method of claim 1, wherein the controlling of the robot cleaner comprises: When the time reaches the maximum value, the robot cleaner is a method for detecting an obstacle, characterized in that for moving the robot cleaner further by a predetermined distance, changing the direction of movement. The method of claim 1, wherein the controlling of the robot cleaner comprises: The obstacle detection method of the robot cleaner, characterized in that for moving the robot cleaner in accordance with the proximity distance to the obstacle set by the user. The method of claim 1, wherein the controlling of the robot cleaner comprises: Setting an intensity of the infrared signal; And And controlling the operation of the robot cleaner when the intensity of the received infrared signal decreases by the intensity of the set infrared signal from the maximum value. In the robot cleaner for detecting the distance to the obstacle using an infrared sensor provided therein, A radiator for outputting an infrared signal for detecting the obstacle; A detector configured to receive an infrared signal reflected from the obstacle; A control unit for detecting a time point when the intensity of the received infrared signal reaches a maximum value, determining a distance to the obstacle based on the detected time point, and outputting a control signal for controlling the operation of the robot cleaner accordingly ; And And a driving unit for operating the robot cleaner by receiving the control signal. The method of claim 7, wherein the detection unit, And a voltage corresponding to the magnitude of the received infrared signal to the controller. The method of claim 7, wherein the control unit, And the maximum value is detected based on a time point at which the change amount of the slope of the intensity of the infrared signal becomes zero. The method of claim 7, wherein the control unit, And calculating a difference between an obstacle proximity distance set by a user and a distance at the point of time of reaching the maximum value, and storing a voltage corresponding to the distance in a memory provided therein. The method of claim 10, wherein the control unit, And when the magnitude of the voltage received from the detector corresponds to a difference between the magnitude of the voltage corresponding to the maximum value and the magnitude of the voltage stored in the memory, changing the moving direction of the robot cleaner. The method of claim 7, wherein the control unit, And calculating the difference between the obstacle proximity distance set by the user and the distance at the point of time when the maximum value is reached, and storing the distance in a memory provided therein. The method of claim 10, wherein the control unit, And the moving direction of the robot cleaner is changed when the moving distance after the point of time when the maximum value is reached corresponds to the moving distance stored in the memory.

Images