A vacuum cleaner comprising a distance sensor

Abstract

The present invention relates to a robot vacuum cleaner (1) comprising a body (2); an optical sensor (6) which is positioned on the front surface (3) of the body (2); a movable bumper (4) which is positioned so as to cover the front surface (3) of the body (2); a window (5) which is positioned on the bumper (4) so as to align with the said optical sensor (6) and provide a viewing angle for the optical sensor (6); and a control unit (7) which is positioned on the body (2), which is in communication with the optical sensor (6), which reads distance and / or optical density and / or reflection data from at least one multi-pixel or single-pixel image in the field of view of the optical sensor (6), which detects changes in the data and which associates the location of the pixel(s) where the change occurs the most with the side of the bumper (4) where the impact occurred.

Description

Technical Field

[0001] The present invention relates to a self-propelled cleaning device for automatically cleaning floor surfaces, particularly to a robot vacuum cleaner.State of the Art

[0002] The state of the art mobile robots operate by navigating within an environment. The mobile robot comprises a bumper which contacts obstacles encountered by the mobile robot while moving. Upon detecting that the bumper has come into contact with an obstacle in the environment, the mobile robot may change its behavior. For example, the mobile robot may retreat from the obstacle or change path in another manner. In some mobile robots, the bumper comprises mechanical switches which provide a binary indication showing whether the bumper has contacted an obstacle.

[0003] A bumper for a state of the art mobile robot may detect contact with obstacles in an environment by using sensors which detect the movement of the bumper. For example, each sensor may be a capacitive sensor having a plate mounted so as to move with the bumper relative to the chassis, and another plate mounted to remain stationary relative to the chassis. Depending on the movement of the bumper, the movement of one plate relative to the other causes the capacitive sensor to generate an electrical signal having a magnitude or value proportional to the distance between the plates. Thus, the electrical signal varies within a range of values according to the movement of the bumper. A controller interprets the electrical signals generated by the sensors to determine characteristics such as the location, magnitude, and duration of the force applied to the bumper. Here, various systems are disclosed for detecting contact, forces applied, and displacement of bumpers used in mobile robots.

[0004] In the state of the art Patent Document No. EP3366183B1, a robot vacuum cleaner is disclosed, comprising a movable body, a bumper and a plurality of sensors, wherein the bumper moves in response to a force applied to the body, and the said magnetic sensors generate an electrical signal proportional to the displacement of two parts.Brief Description of the Invention

[0005] The aim of the present invention is the realization of a robot vacuum cleaner which enables the distance between the robot and obstacles to be measured with high accuracy so as to allow for more precise obstacle detection and improve obstacle detection performance.

[0006] Another aim of the present invention is to reduce the number of mechanical and electronic components used for obstacle detection in the robot vacuum cleaner by using high-precision optical sensors while increasing the durability and reliability of the internal structure of the robot vacuum cleaner.

[0007] Yet another aim of the present invention is to ensure that the travel behaviors of the robot vacuum cleaner can be updated by determining the moment of contact and the contact characteristics when the robot vacuum cleaner encounters obstacles.

[0008] Yet another aim of the present invention is to detect obstacles encountered from both the sides and the front of the robot vacuum cleaner so as to prevent the same from getting stuck between obstacles and to increase performance. Thus, the energy efficiency and economic life of the robot vacuum cleaner are increased.

[0009] The said figures are: Figure 1: shows the changes in pixel values in the images obtained from the optical sensor comprising the surface and the obstacle object. Figure 2: shows the changes in pixel values in the images obtained from the optical sensor comprising the surface and the obstacle object. Figure 3: shows the data received from the optical sensor when the bumper is not exposed to any movement and is in a static state. Figure 4: shows the data received from the optical sensor at the moment when the bumper moves to the right direction after impact. Figure 5: shows the data received from the optical sensor at the moment when the bumper moves to the left direction after impact. Figure 6: shows the data received from the optical sensor on the front surface of the bumper during the impact. Figure 7: is the front top perspective view of the robot vacuum cleaner. Figure 8: is the front perspective view of the robot vacuum cleaner. Figure 9: is the top perspective view of the robot vacuum cleaner.

[0010] The elements illustrated in the figures are numbered as follows: 1. Robot vacuum cleaner 2. Body 3. Front surface 4. Bumper 5. Window 6. Optical sensor 7. Control unit Detailed Description of the Invention

[0011] The robot vacuum cleaner (1) of the present invention comprises a body (2); an optical sensor (6) which is positioned on the front surface (3) of the body; a movable bumper (4) which is positioned to cover the front surface of the body (2); a window (5) which is positioned on the bumper (4) so as to align with the said optical sensor (6) and provide a viewing angle for the optical sensor (6); and a control unit (7) which is positioned on the body (2) and which is in communication with the optical sensor (6). The optical sensor (5) positioned at the center of the front surface (3) of the robot vacuum cleaner (1) performs the task of detecting objects and obstacles. The said optical sensor (5) provides various measurement data depending on the movement direction of the robot vacuum cleaner (1) through the window (5) provided on the bumper (4). The said window (5), which is positioned on the bumper (4) to align with the optical sensor (6) on the bumper, enables the optical sensor (6) to perform accurate detection without disturbing the wide field of view. However, changes in the field of view of the optical sensor (6) resulting from the movement of the bumper (4) due to collision with the said obstacles create variations in detection depending on the intensity and direction of the impact.

[0012] In an embodiment of the present invention, the robot vacuum cleaner (1) comprises a body (2); an optical sensor (6) which is positioned on the front surface (3) of the body (2); a bumper (4) which is positioned so as to cover the front surface (3) of the body (2) and which can move under the effect of impact; a window (5) which is positioned on the bumper (4) so as to align with the said optical sensor (6) and provide a viewing angle for the optical sensor (6); and a control unit (7) which is positioned on the body (2), which is in communication with the optical sensor (6), which reads the data from at least one multi-pixel or single-pixel distance and / or optical density and / or reflection data included in the image in the field of view of the optical sensor (6), which detects changes in the data and which associates the position of the pixel(s) with the greatest change with the side of the bumper (4) where the impact occurred. By reading a plurality of multi-pixel or single-pixel image data, time and distance measurement can be performed more quickly and accurately. Moreover, in cases such as dust accumulation on the optical sensor (6), correct measurement can be achieved by performing validation with a plurality of distance and / or optical density and / or reflection data to prevent problems in the data read and obtain accurate results.

[0013] In an embodiment of the present invention, the robot vacuum cleaner (1) comprises a control unit (7) which examines at least one multi-pixel or single-pixel image in the field of view of the optical sensor (6), which detects from the decrease in the pixel(s) that the distances between the obstacle and the bumper (4) have decreased, which interprets this as a collision and which associates the location of the pixel(s) with the greatest decrease in distance with the side of the bumper (4) where the impact occurred.

[0014] The impact side can be determined based on the alignment of the pixels where the decrease occurs. For example, the robot vacuum cleaner (1) comprises a control unit (7) which understands the impact came from the right if the distance decreases in pixels near the right side.

[0015] In an embodiment of the present invention, each pixel in the data received from the optical sensor (6) represents the distance information between a specific region on the bumper (4) and the obstacle. In an embodiment of the present invention, the robot vacuum cleaner (1) comprises a control unit (7) which is in communication with the optical sensor (6), which analyzes the optical sensor (6) data by examining the groups of pixels where low distance values are concentrated and which determines from which region of the bumper (4) the impact originated.

[0016] In another embodiment of the present invention, the control unit (7) uses reflection and / or optical density data to determine from which region of the bumper (4) the impact originated. The robot vacuum cleaner (1) comprises a control unit (7) which analyzes the information that the distance between the obstacle and the region of the bumper (4) where the impact occurred is decreasing, based on the alignment of pixels wherein there is an increase in reflection and / or optical density data obtained from at least one multi-pixel or single-pixel image in the field of view of the optical sensor (6) and which determines from which region of the bumper (4) the impact originated. Thus, the control unit (7) may decide, based on the reflection and / or optical density data, whether the window (5), which is positioned to provide a viewing angle for the optical sensor (6) due to the movement of the bumper (4) after impact with the obstacle, changes the field of view of the optical sensor (6).

[0017] Figures 1 to 6, which illustrate an embodiment of the present invention, represent multi-pixel image data in the field of view of the optical sensor (6). The said images correspond to a depth map of 8×8 pixels. The value in each pixel represents the distance in millimeters. In the figures, dark-colored pixel values represent close distance values, while light-colored pixel values represent distant values. Pixel values below 250 mm are shown as dark, while values above 250 mm are shown in light colors. The said values are given to explain the present invention and the present invention is not limited to the said values.

[0018] In an embodiment of the present invention, the robot vacuum cleaner (1) comprises a control unit (7) which, for distance data as seen in any of Figures 1 to 6, detects distance change among the distance data received from the optical sensor (6), which determines the area where low distance values are clustered and which detects the direction based on the distance differences. As seen in any of Figures 1 to 6, the distance values in a certain part of the bumper (4) are lower compared to other regions. For example, in Figure 4, the low distance values in the lower left region (pixel positions: columns 0 and 1) are shown in light tones. The said low distance values indicate that the impact or an object is near this area of the bumper (4).

[0019] In an embodiment of the present invention, the control unit (7) determines on which side of the bumper (4) (right, left, bottom, or top) the impact occurred by examining the pixel groups where low distance values are concentrated. The direction of distance decreases plays a critical role in determining the direction of the impact. For example, in case the impact occurs near the right side of the bumper (4), the distances of the pixels on the right decrease, and the same decrease applies to impacts on the left, bottom, or top sides of the bumper (4). While the low distance values in the lower right region in Figure 4 indicate that the impact came from the right, in Figure 5 the low distance values in the lower left region indicate that the impact came from the left.

[0020] In an embodiment of the present invention, the control unit (7) temporally monitors the data received from the optical sensor (6). Sudden decreases in distance occur at the moment when the bumper (4) impacts an obstacle. The control unit (7) determines the moment of impact by monitoring the time-varying distance values of each pixel. For example, in Figure 2, the suddenly decreasing distance values in the lower left corner indicate that the impact has occurred on this side. Similarly, as seen in any of Figures 1 through 6, the area with low distance values helps determine the direction and region of the impact.

[0021] The analysis by the control unit (7) of the data received from the optical sensor (6) enables the robot vacuum cleaner (1) to understand the direction of the collision with the obstacle and the side from which the impact occurred. In the optical sensor (6) data, if the distance decreases are concentrated in certain pixel groups, the control unit (7) detects that an impact or obstacle is approaching from that region.

[0022] In an embodiment of the present invention, Figures 1 and 2, columns 0 and 7 show the pixels in which the change in bumper (4) movement is detected. Moreover, in the images obtained from the said optical sensor (6), the pixel values also represent the surface and the object acting as the obstacle. The color tones seen in the figures represent changes in detection distances under different impact scenarios. The dark-colored areas show the distorted field of view of the optical sensor (6) after the impact and the regions where the measurement accuracy is reduced, while the light-colored areas represent the regions where the optical sensor (6) performs clearer detection.

[0023] In an embodiment of the present invention, Figure 3 shows the data provided by the optical sensor (6) in a static condition where the bumper (4) is not exposed to any movement. In this case, the optical sensor (6) has a wide field of view and can detect obstacles accurately. The color scale seen in the graph indicates that the detection distances of the optical sensor (6) are equal at every point and that there is no distortion on the bumper (4), and the said distortion in the field of view corresponds to the pixel groups where distance decreases are concentrated. In this static condition, the optical sensor (6) measures the distance to obstacles with high accuracy and no deviation occurs in detection due to external factors.

[0024] In an embodiment of the present invention, Figure 4 shows the data received from the optical sensor (6) at the moment when the bumper (4) moves to the right direction after impact. During this movement, a significant distortion is observed in the field of view on the right side of the bumper (4) as detected by the optical sensor (6). This distortion in the field of view corresponds to the pixel groups where distance decreases are concentrated. The color distribution shows that there is deterioration in the detection of the view on the right side of the bumper (4) and that the optical sensor (6) has a more limited field of view in this region. This indicates that the optical sensor (6) detects obstacles on the right side with lower sensitivity and that the impact came to the right side of the robot vacuum cleaner (1). This data shows that the bumper (4), which moves toward the right, significantly affects the detection range of the optical sensor (6).

[0025] In an embodiment of the present invention, Figure 5 shows the data received from the optical sensor (6) at the moment when the bumper (4) moves to the left direction after impact. During this movement, a significant distortion is observed in the field of view on the left side of the bumper (4) as detected by the optical sensor (6). This distortion in the field of view corresponds to the pixel groups where distance decreases are concentrated. On the graph, it is clearly seen that detection weakens on the left part of the bumper (4) and the optical sensor (6) has more difficulty detecting obstacles in this region. The areas shown in dark color indicate the distorted field of view of the optical sensor (6) due to the direction of impact and a decrease in obstacle detection capacity. This movement shows that the robot vacuum cleaner (1) received an impact on the left side and that this region of the bumper (4) restricts the field of view of the optical sensor (6).

[0026] In an embodiment of the present invention, Figure 6 shows the movement of the bumper (4) on the front surface during the impact. In this case, an impact occurring on the front part of the bumper (4) is the situation that affects the detection range of the optical sensor (6) the most. The color distribution seen in the graph indicates that an impact on the front part of the bumper (4) causes significant degradation in the detection capability of the optical sensor (6) in this area. This distortion in the field of view corresponds to the pixel groups where distance decreases are concentrated. The dark-colored areas indicate that, after an impact on the front part of the bumper (4), the optical sensor (6) is unable to detect obstacles or that the measurement accuracy has significantly decreased. This situation shows that an impact on the front part of the robot vacuum cleaner (1) is the factor which affects the field of view of the optical sensor (6) the most.

[0027] In an embodiment of the present invention, the optical sensor (6) is a ToF (time-of-flight) sensor. The ToF sensor (6) can detect the distance of the robot vacuum cleaner (1) to obstacles with high accuracy by means of the window (5) provided on the bumper (4). However, the movement of the bumper (4) at the moment of collision and the direction of the impact affect the field of view and detection capacity of the ToF sensor (6). The data shown in the figures clearly reveal the direction from which the impact came and the regions wherein the ToF sensor (6) is less effective. Thus, while the ability of the robot vacuum cleaner (1) to detect obstacles in the environment is improved, the distortion in the data from the ToF sensor (6) after impact can also be detected.

[0028] In an embodiment of the present invention, the optical sensor (6) receives incoming data and provides distance information from different angles so as to determine which part of the bumper (4) was hit by the obstacle. The said optical sensor (6) determines the direction and location of the impact by analyzing the distance information coming from different regions on the bumper (4). The control unit (7) analyzes anomalies and changes in the said data to determine from which point the impact came. For example, when an impact occurs on a corner of the bumper (4), the pixel data of the optical sensor (6) in that region reports shorter distances than in other regions. By means of this difference, the control unit (7) can understand on which side and in which direction the impact occurred. In response to the detection of contact with an obstacle and the determination of the characteristics of the contact, the control unit (7) can adjust the travel behavior of the robot vacuum cleaner (1) to avoid obstacles in the environment. The communication between the optical sensor (6), which can also detect overhead obstacles, and the control unit (7) reduces the risk of the robot (1) becoming trapped between obstacles and the floor surface. Thanks to the high precision of the optical sensors (6), the bumpers (4) whereon the optical sensors (6) described here are used may reduce the number of moving components visible to the user of the robot vacuum cleaner (1). Moreover, thanks to the high sensitivity of the optical sensors (6), the displacement of the bumper (4) is accurately measured by the control unit (7), and thus the total movement amount of moving components can be reduced compared to bumper systems based on mechanical switches and / or electromechanical sensors. The sensors (6) are designed to respond to forces along the bumper (4) in varying degrees so as to improve the operation of the robot vacuum cleaner (1).

Claims

1. A robot vacuum cleaner (1) comprising a body (2); an optical sensor (6) which is positioned on the front surface (3) of the body (2); a bumper (4) which is positioned so as to cover the front surface (3) of the body (2) and which can move under the effect of impact; and a window (5) which is positioned on the bumper (4) so as to align with the said optical sensor (6) and provide a viewing angle for the optical sensor (6); characterized by a control unit (7) which is positioned on the body (2), which is in communication with the optical sensor (6), which reads the data from at least one multi-pixel or single-pixel distance and / or optical density and / or reflection data included in the image in the field of view of the optical sensor (6), which detects changes in the data and which associates the position of the pixel(s) with the greatest change with the side of the bumper (4) where the impact occurred.

2. A robot vacuum cleaner (1) as in Claim 1, characterized by a control unit (7) which examines at least one multi-pixel or single-pixel image in the field of view of the optical sensor (6), which detects from the decrease in the pixel(s) that the distances between the obstacle and the bumper (4) have decreased, which interprets this as a collision and which associates the location of the pixel(s) with the greatest decrease in distance with the side of the bumper (4) where the impact occurred.

3. A robot vacuum cleaner (1) as in Claim 1, characterized by a control unit (7) which analyzes the information that the distance between the obstacle and the region of the bumper (4) where the impact occurred is decreasing, based on the alignment of pixels wherein there is an increase in reflection and / or optical density data obtained from at least one multi-pixel or single-pixel image in the field of view of the optical sensor (6) and which determines from which region of the bumper (4) the impact originated.

4. A robot vacuum cleaner (1) as in any one of the above claims, characterized by a control unit (7) which determines the moment of impact by monitoring sudden changes in the varying distance values at the moment the bumper (4) hits an obstacle.

5. A robot vacuum cleaner (1) as in any one of the above claims, characterized in that the optical sensor (6) is a ToF (time-of-flight) sensor.

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