KR20090008720A - Mobile robot and its controlling method thereof - Google Patents

Abstract

A mobile robot is provided to facilitate traveling of the robot to a space with a low height by sensing a wide area in the horizontal direction, and a controlling method of the mobile robot is provided. A mobile robot(100) comprises: a case(110); and a sensor unit(12) which is correspondingly disposed on an outer side surface of the case and includes two or more transmitting parts(121) and receiving parts(125). The transmitting parts and receiving parts are alternately formed on the outer side surface of the case. The receiving parts each includes a first sensor disposed at the center of a front side of the case, and second and third sensors disposed at left and right sides of the first sensor such that the second and third sensors are spaced from the first sensor.

Description

Mobile robot and its controlling method

1 is a perspective view showing a mobile robot according to an embodiment of the present invention,

2 is a side view of a mobile robot according to an embodiment of the present invention;

3 is a schematic cross-sectional view showing an ultrasonic sensor of a mobile robot according to an embodiment of the present invention;

4 is a view showing the ultrasonic sensor of FIG.

5 shows another embodiment of the ultrasonic sensor of FIG. 3;

6 is a view showing a received signal of the ultrasonic sensor according to an embodiment of the present invention, and

7 and 8 are graphs showing signals obtained by an ultrasonic sensor according to an embodiment of the present invention.

<Simple description of the code for the main part of the drawing>

100: mobile robot 110: case

112: bumper 120: sensor unit

121, 121a, 121b: transmitter 125: receiver

125a: first sensor 125b: second sensor

125c: third sensor

The present invention relates to a mobile robot and a control method thereof to solve the obstacle measurement impossible area by providing a plurality of transmitters and receivers.

Mobile robots inhale dust or foreign substances by moving themselves in a certain space such as a house or office.

Here, the mobile robot includes a driving means including a right / left wheel motor for moving the mobile robot along with a configuration of a general vacuum cleaner that sucks dust or foreign matter, a detection sensor for detecting / avoiding various obstacles in the cleaning area, a driving means and It consists of a control means for controlling the detection sensor and the like to be made.

The mobile robot according to the related art detects an obstacle by installing an ultrasonic sensor on the surface of the case. In this case, the ultrasonic sensor includes a transmitter and a receiver, and the transmitter and the receiver are installed at a predetermined distance apart from each other, and receive an ultrasonic wave transmitted from the transmitter at the receiver to recognize an obstacle.

However, the mobile robot according to the prior art is limited in the range and angle of detecting the signal reflected through the obstacle, there is a problem that can not recognize the obstacle with a large reflection angle, such as a rectangular column.

Accordingly, an object of the present invention is to provide a mobile robot and a control method according to the present invention, which eliminates the obstacle measuring area by providing a plurality of transmitters and receivers.

The mobile robot according to the present invention for solving the above problems is disposed to correspond to the case and the outer surface of the case, each comprising a sensor unit having at least two transmitters and receivers. Here, the transmitter and the receiver are provided to cross each other.

In addition, the mobile robot according to the present invention is disposed on the case, the outer surface of the case, the position of the obstacle based on at least two sensor units provided with at least two transmitters and receivers and received through the sensor unit. It further comprises a control means for detecting.

In addition, the control method of the mobile robot according to the present invention is a control method of a mobile robot including a case, a sensor unit disposed on the outer surface of the case, the transmitter and the receiver is provided and a control means for controlling the sensor unit. The sensor unit may include at least two transmitters and a receiver, respectively, and the control unit may be a signal received through the at least two receivers by being reflected by an obstacle among signals transmitted through the at least two transmitters. Based on, detect the position of the obstacle.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view showing a mobile robot according to the present invention, Figure 2 is a side view of the mobile robot shown in FIG.

As shown in FIGS. 1 and 2, the mobile robot 100 is disposed to correspond to the case 110 and the outer surface of the case 110 to form an exterior, and each includes at least two or more transmitters 121. It includes a sensor unit having a receiver 125. At this time, the case 110 is formed in a circular disk shape having a predetermined height. The sensor unit is a sensor that detects a distance from a wall or an obstacle in the room. In the embodiment of the present invention, the sensor unit is an ultrasonic sensor 120.

In addition, the case 110 is provided with a bumper 112 to cushion the impact during the collision.

Meanwhile, although not shown in FIGS. 1 and 2, the case 110 includes an air suction device, a suction nozzle unit, and a dust collector in communication with the suction nozzle unit. In addition, at least one auxiliary wheel is provided at the bottom of the case 110 to prevent the bottom surface of the case 110 from directly contacting the floor and to minimize friction between the mobile robot 100 and the floor. In addition, a control means in which various electric components for controlling the driving of the mobile robot 100 are arranged is provided, and a battery is provided for supplying power to each component of the control means.

At this time, the control means detects the position of the obstacle based on at least two signals received through the ultrasonic sensor 120, and controls the movement of the mobile robot 100 in accordance with the detected position of the obstacle.

Hereinafter, the ultrasonic sensor will be described in more detail with reference to FIGS. 3 to 5.

First, Figure 3 is a cross-sectional view showing a schematic configuration of an ultrasonic sensor according to an embodiment of the present invention. Referring to FIG. 3, the ultrasonic sensor 120 provided on the outer surface of the case 110 may be provided such that at least two or more transmitters 121 and receivers 125 cross each other. Therefore, as the signal is radiated at various angles and the signal reflected at the obstacle is received at various angles, the obstacle measurement area cannot be reduced by detecting a wall reflection angle by a conventional mobile robot.

In other words, the receiver 125 may include a first sensor 125a disposed at the front center of the case 110, a second sensor 125b disposed at a left side and a right side spaced apart from the first sensor 125a, and a third sensor ( 125c). In this case, the reception sensitivity of the first sensor 125a is set lower than the reception sensitivity of the second sensor 125b and the third sensor 125c.

On the other hand, the transmitting unit 121 is disposed to be spaced apart from the left and right side from the front center of the case 110. That is, at least one sensor 121a is disposed between the first sensor 125a and the second sensor 125b of the receiver 125, and at least one between the first sensor 125a and the third sensor 125c. Sensors 121b are disposed respectively. In addition, the transmitter 121 simultaneously oscillates ultrasonic waves through the sensors 121a and 121b. At this time, the oscillation angle of the ultrasonic wave oscillated through the sensors 121a and 121b maintains an angle within a range that does not affect the different signals, so that no crosstalk phenomenon occurs.

FIG. 4 is a diagram illustrating a transmitter and a receiver of the ultrasonic sensor illustrated in FIG. 3, wherein FIG. 4A is a diagram illustrating a schematic configuration of a transmitter and a receiver.

First, as shown in (a) of FIG. 4, the transmitter 121 is formed such that the sensors 121a and 121b have a horn shape. Here, the sensors (121a, 121b) is formed so that the outer end has an elliptic shape, the ellipse is formed so that the long axis is the axis of the longitudinal section. That is, as the shortening of the ellipse forms the horizontal direction of the mobile robot 100, the wide area of the mobile robot 100 can be detected in the horizontal direction of the mobile robot 100, so that driving to a space having a low height such as under a bed or a sofa can be prevented. Make it possible.

In this case, the first sensor 125a is set to a sensitivity enough to detect an obstacle when traveling in a space having a low height such as under a bed or a sofa. Of course, since the second sensor 125b and the third sensor 125c should set sensitivity enough to detect an obstacle when driving in general, the reception sensitivity is set higher than that of the first sensor 125a.

Referring to FIG. 4B, the receiver 125 is provided with a condenser microphone in a scanning manner. Here, in the condenser microphone, when the diaphragm vibrates due to sound (ultrasound), the capacitance of the condenser changes, and the accumulated charge changes, and as a result, a current flows due to the change of sound. In this case, the control means detects the current signal, thereby detecting the ultrasonic waves received through the receiver 125.

5 is a diagram illustrating another embodiment of FIG. 3, (a) of FIG. 5 illustrates another embodiment of a first sensor of a receiver, and (b) shows a second sensor and a third sensor of the receiver. Another embodiment is shown.

As shown in FIG. 5, the receiver 125 is provided with at least one first sensor 125a, a second sensor 125b, and a third sensor 125c, respectively. In other words, as shown in FIG. 5A, by providing one or more first sensors 125a provided in the central portion, the reception ratio of the central portion is increased. On the other hand, as shown in Figure 5 (b), by installing one or more of the second sensor (125b) and the third sensor (125c) provided on the left and right, it is possible to detect obstacles of various angles.

Of course, as shown in (a) and (b) of FIG. 5, the quantity of the first sensor 125a, the second sensor 125b, and the third sensor 125c may be changed and installed. This is not limited to the sensor of the receiver 125, and may be applicable to the sensor of the transmitter 121.

6 is an exemplary view illustrating an embodiment of a signal detected through the receiver of the present invention.

First, FIG. 6A illustrates an analog signal obtained by converting an ultrasound signal received through a receiver. In addition, as shown in FIG. 6B, the received signal is amplified while passing through an amplifier and then filtered through a band pass filter.

Here, the control means compares the filtered signal level with the reference value α, based on the filtered signal. At this time, the control means calculates a time of flight (hereinafter referred to as 'TOF') from the moment T1 when the filtered signal exceeds the reference value α to the moment T2 that falls below the reference value. In addition, the control means detects the distance and direction to the obstacle based on the calculated TOF value. An embodiment of detecting an obstacle using a 'TOF' value will be described with reference to FIGS. 7 and 8.

FIG. 7 is a diagram illustrating an embodiment of the ultrasonic sensor illustrated in FIG. 3. FIG. 6A illustrates a TOF value calculated from a signal detected for a cylindrical obstacle 'ga', and (b). Is a diagram showing the TOF value calculated from the detected signal for the polygon obstacle 'I'. FIG. 8 is a diagram referred to for explaining FIG. 7A in more detail.

Referring to FIG. 8, first, the black bottom center shows the shape of the mobile robot 100, and the numerical values shown in the graph represent TOF values in the respective areas A to E. FIG. At this time, the first sensor 125a of the receiver 125 is at the end of the 'C region' which is the center of the mobile robot 100, and the second sensor 125b of the receiver 125 is at the end of the 'A region'. The third sensor 125c of the receiver 125 is provided at the end of the 'E region'. Further, sensors 121a and 121b of the transmitter 121 are provided at the end of the 'B area' and the 'D area', respectively.

At this time, when ultrasonic waves are simultaneously oscillated from the sensors 121a and 121b of the transmitting unit 121 provided at the ends of the 'B region' and the 'D region', the oscillated signal is reflected by an obstacle to the first sensor 125a, It is received through the second sensor 125b and the third sensor 125c. The control unit calculates a TOF value for the signal received through the receiver 125 and distinguishes the 'A region' from the 'E region' according to the calculated value.

The control means sets the reception angles of the first sensor 125a, the second sensor 125b, and the third sensor 125c with respect to the signals received from the positions of the 'A region', the 'C region', and the 'E region'. do. Further, the control means calculates the distance value of the obstacle from the first sensor 125a, the second sensor 125b, and the third sensor 125c, respectively, based on the TOF values of the 'region A' to the 'E region'. . Meanwhile, the control means detects a direction in which an obstacle is located from the mobile robot 100 by using TOF values of 'B area' and 'D area' provided with the sensors 121a and 121b of the transmitter 121. . At this time, the control means may also detect the shape of the obstacle from the TOF value calculated for the detected obstacle.

In addition, in the case of FIG. 7B, it is possible to calculate a distance and a direction from the TOF value calculated for the obstacle 'I' as described above, and detect the shape of the obstacle 'I' from the detected signal region. You can do it.

In this embodiment, the ultrasonic sensor has been described as an example, but the sensor unit is not limited to the ultrasonic sensor, and includes all sensors that generate signals and receive reflected signals.

Hereinafter, the operation of the mobile robot configured as described above will be described in more detail.

First, the transmitting unit 121 of the ultrasonic sensor 120 simultaneously transmits ultrasonic waves through two or more sensors, and the transmitted ultrasonic signals are radiated to a predetermined area.

The emitted ultrasonic signal is reflected from an obstacle, and the reflected signal is received through the first sensor 125a, the second sensor 125b, and the third sensor 125c of the receiver 125.

Meanwhile, the control unit calculates a TOF value based on the reception time of the signal received through the first sensor 125a, the second sensor 125b, and the third sensor 125c and the level of the received signal. At this time, the level of the received signal is compared with the preset reference value α, and the time taken from the moment T1 when the level of the received signal exceeds the reference value α to the moment T2 falling below the reference value T2-T1. ) Is calculated.

At this time, the control means detects the distance and direction to the obstacle based on the calculated TOF value, and controls the movement of the mobile robot 100 according to the detected result value.

As described above, the mobile robot and the control method thereof according to the present invention have been described with reference to the illustrated drawings, but are not limited to the embodiments and drawings disclosed herein, and those skilled in the art within the scope of protection of the technical idea of the present invention. Application is possible.

As described above, the mobile robot and its control method of the present invention by placing a plurality of transmitters and receivers to cross each other, giving a direction to the range of the transmitter and the receiver of the sensor unit, and received through a plurality of receivers By dividing the signal by a specific value, there is an advantage that the obstacle can be detected more accurately by minimizing the area where the obstacle cannot be measured.

In addition, it is possible to detect a wide area in the horizontal direction, there is an advantage that it is easy to travel to a low height space, such as under the bed or sofa.

Claims (14)

case; And It is disposed so as to correspond to the outer surface of the case, each sensor unit having at least two transmitters and receivers; The mobile robot is provided so that the transmitter and the receiver to cross each other. The method of claim 1, The receiving unit may include a first sensor disposed at the front center of the case; And a second sensor and a third sensor arranged to be spaced apart from the first sensor to the left and the right. The method of claim 2, The receiving unit, wherein the reception sensitivity of the first sensor is set lower than the reception sensitivity of the second sensor and the third sensor. The method of claim 2, The receiving unit, each of the at least one first sensor, the second sensor and the third robot is provided with a third sensor. The method of claim 1, The transmitting unit is disposed so as to be spaced apart from the left and right sides from the front center of the case. The method of claim 1, The transmitter is a mobile robot formed so that the sensor has a horn (horn) shape. The method of claim 6, The sensor is a mobile robot formed so that the outer end has an elliptic shape. The method of claim 7, wherein The ellipse is a mobile robot formed so that the long axis is the axis of the longitudinal section. The method of claim 1, The sensor unit is a mobile robot that is an ultrasonic sensor. case; A sensor unit disposed on an outer surface of the case and having at least two transmitters and receivers; And And a control means for detecting the position of the obstacle based on at least two signals received through the sensor unit. case; A sensor unit disposed on an outer surface of the case and provided with a transmitter and a receiver; In the control method of the mobile robot comprising a control means for controlling the sensor unit, The sensor unit is provided with at least two transmitters and receivers, respectively, The control means is a control method of a mobile robot for detecting the position of the obstacle based on the signal received through the at least two receivers reflected from the obstacles transmitted through the at least two transmitters. The method of claim 11, The control means, the control method of the mobile robot to control the ultrasonic wave to be oscillated simultaneously through the at least two or more transmitters. The method of claim 11, The control means, the control method of the mobile robot for measuring the distance to the obstacle by detecting a time (TOF, Time Of Flight) taken until the level of the signal received through the at least two receiving unit exceeds a reference value. The method of claim 11, The control means, the control method of the mobile robot for detecting the time (TOF, Time Of Flight) taken until the level of the signal received through the at least two receiving unit exceeds a reference value, the obstacle is located.

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