JP4429850B2 - Self-propelled working robot - Google Patents

Description

  The present invention relates to a work robot suitable for work on a floor or the like near a wall.

2. Description of the Related Art Conventionally, a self-propelled working robot that performs work such as cleaning a floor surface near a wall has been proposed (see Patent Document 1).
JP-A-4-260905 (3rd page, FIG. 1)

  The working robot of Patent Document 1 includes a plurality of distance sensors that measure the distance from the main body to the obstacle. When the distance measured by the distance sensor is smaller than a predetermined threshold, the robot performs a predetermined avoidance operation and is controlled so as not to collide with the wall. The threshold value is set to a predetermined constant value so that the robot does not move too far from the wall.

  However, if the threshold is not sufficiently increased, if the inclination angle between the main body and the obstacle is large (for example, FIG. 7D), the top of the central part of the robot is not approaching the obstacle. First, the side of the front end of the robot approaches the obstacle. Therefore, there is a possibility that the detection is delayed and the robot collides with the obstacle.

  Accordingly, an object of the present invention is to provide a self-propelled working robot that can detect various obstacles with high accuracy.

  In order to achieve the above object, the present invention is a self-propelled type equipped with a first distance sensor for measuring a distance to an obstacle ahead and a second distance sensor for measuring a distance to an obstacle ahead obliquely. In the work robot, a first determination unit that compares the first measured distance to the obstacle measured by the first distance sensor and a predetermined first threshold to determine the approach of the obstacle, and the second distance A second determination means for determining the approach of the obstacle by comparing the second measurement distance to the obstacle measured by the sensor and a predetermined second threshold; and the obstacle obtained from the first and second measurement distances And changing means for changing the first threshold value or the second threshold value based on information related to the inclination angle of the object.

  According to the present invention, by detecting the obstacle by the first and second discriminating means, and changing the first threshold value or the second threshold value based on the information about the inclination angle of the obstacle, Even an obstacle with a large inclination angle can be detected with high accuracy.

  In the present invention, the information regarding the tilt angle is based on the arrangement of the first and second distance sensors, the light emission directions of the first and second distance sensors, and the first and second measurement distances. Obtainable.

Here, “front” is defined based on the traveling direction of the work robot.
Further, as the “inclination angle of the obstacle obtained from the first and second measurement distances”, for example, as shown in FIG. 6, the normal L perpendicular to the surface of the obstacle W and the traveling direction of the robot This is the angle θ formed by F.

In a preferred embodiment of the present invention, the determination result of whether or not the obstacle is approached by the first determining means regardless of the inclination angle, and whether or not the obstacle is approached by the second determining means. When it is determined that one of the two determination results approaches, the robot determines that the robot has approached the obstacle.
When the first distance is smaller than the second distance, the first determination means determines that the robot has approached the obstacle, not the second determination means. On the other hand, when the first distance has a larger tilt angle than the second distance, it is not the first determining means but the second determining means that determines that the robot has approached the obstacle. Therefore, the approach can be determined and determined regardless of the angle of inclination.
However, in the present invention, when the tilt angle is smaller than a predetermined value, it is determined whether or not the obstacle has approached based on the determination result by the first determination means, while the tilt angle is If is greater than a predetermined value, it may be determined whether or not the obstacle has approached based on the determination result by the second determination means.
In this way, by using the discrimination result by the first discrimination means in front and the discrimination result by the second discrimination means in front of the obstacle based on the inclination angle of the obstacle, the obstacle regardless of the inclination angle of the obstacle. Can be detected.

  In the present invention, the changing means sets the first threshold value or the second threshold value so that the first threshold value or the second threshold value increases as the tilt angle increases. Thus, by increasing the first threshold value or the second threshold value, the obstacle can be detected before the side portion of the front end of the robot contacts the obstacle.

In the present invention, it is preferable that the first and second distance sensors are arranged close to each other. In this case, the first distance and the second distance are compared, and if the first distance is smaller than the second distance as a result of the comparison, the failure is determined based on the determination result by the first determination means. If the first distance is greater than the second distance as a result of the comparison, the determination result by the second determination means (or the first determination means) is determined. Whether or not the obstacle has approached can be determined based on the above. Thus, when both distance sensors are arranged close to each other and the first distance is smaller than the second distance, the first threshold value and the second threshold value may be set to the same value.
As described above, by comparing the first distance and the second distance, the first determination result and the second determination result are selectively used in accordance with the inclination angle between the main body and the obstacle, thereby the inclination angle of the obstacle. Obstacles can be detected regardless of the above.

In the present invention, the first and second distance sensors are optical distance sensors, the first distance sensor is provided at the top of the left and right centers of the robot, and the second distance sensor is a first distance sensor. In addition to the optical first and second distance sensors, a pair of ultrasonic distance sensors that measure the distance to the front obstacle on both sides of the front end of the self-propelled robot. Is preferably provided.
As described above, by using the ultrasonic distance sensor and the optical distance sensor in combination, the obstacle can be detected more accurately.

As an “optical distance sensor”, for example, by irradiating light and grasping part of the light diffusely reflected by the obstacle through the light receiving lens, the distance between the obstacle and the triangulation distance is measured. A commercially available optical distance sensor that is measured by the method can be used.
As an “ultrasonic distance sensor”, for example, a commercially available ultrasonic sensor that measures the distance to an object by emitting an ultrasonic wave and measuring the time until the sound wave returns as a reflected wave from an obstacle. A sonic distance sensor can be used.

In the present invention, the first and second distance sensors are optical distance sensors, the first distance sensor is provided at the top of the left and right centers of the robot, and the second distance sensor is a first distance sensor. A pair is provided close to both sides, and a protective cover is provided at the head portion of the robot, the protective cover includes a concave portion having three side surfaces and a ceiling surface that the three sensors are closely opposed to, and the ceiling surface. It is preferable that a third distance sensor for measuring the distance to the front obliquely lower side is disposed at an inner position opposite to.
As described above, by providing the third distance sensor that detects the obliquely downward front, the unevenness of the front floor surface can be detected. Further, since the distance sensor is provided in the concave portion of the protective cover, it is possible to prevent the surface of the concave portion from being damaged.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In the following embodiments, a case where the self-propelled working robot of the present invention is applied to a self-propelled cleaning robot that sucks up dust on the floor will be described as an example.

  As shown in FIG. 1, the self-propelled working robot according to the present invention includes a carriage-like traveling assembly 1 that self-propels on a floor surface and a working assembly 2 that sucks up dust on the floor. The working assembly 2 is provided behind the traveling assembly 1 with respect to the traveling direction F of the traveling assembly 1.

  A suction unit 51 is provided at the top of the traveling assembly 1. The suction unit 51 is provided with a dust container (tank), a blower motor, a filter, and the like. The suction unit 51 and the work assembly 2 are connected via a suction hose 57. A suction port 59 is provided on the lower surface of the work assembly 2. When the robot performs a cleaning operation while running, floor dust is sucked up from the suction port 59 one after another and the floor surface is cleaned.

Travel assembly 1:
As shown in FIG. 2, the traveling assembly 1 includes a pair of drive wheels 6 a and 6 b for driving the traveling assembly 1, and casters (not shown) at substantially the center of the front and rear portions of the traveling assembly 1. I have. The drive wheels 6a and 6b are driven by drive motors 5a and 5b, respectively. The drive motors 5 a and 5 b can rotate forward and backward, and the traveling of the traveling assembly 1 is controlled by the control unit 8.

  When the vehicle travels straight, the traveling assembly 1 can move forward or backward by rotating the two drive motors 5a and 5b in the same direction. When performing the rotation operation, the two drive motors 5a and 5b can rotate in opposite directions to perform the rotation operation. On the other hand, by controlling the rotation ratio of the two drive motors 5a and 5b, the traveling assembly 1 can also perform curve traveling.

  The working assembly 2 is provided with a mounting plate 11 for attaching the main body 20 of the working assembly 2 to the traveling assembly 1. On the other hand, a slide rail 14 is provided behind the traveling assembly 1 in the left-right direction X substantially orthogonal to the traveling direction F. The mounting plate 11 is attached to the slide rail 14 and is connected to a slide drive motor 15 via a timing belt 12 and a pulley 13. The mounting plate 11 is slid right and left along the slide rail 14 by the slide drive motor 15.

  2, a plurality of ultrasonic distance sensors (hereinafter referred to as “ultrasonic sensors”) 3a to 3d and first to third optical distance sensors (hereinafter referred to as “optical sensors”) are provided at the front portion of the traveling assembly 1 in FIG. 4a-4d).

  Among these sensors, the two ultrasonic sensors 3a and 3b measure the distances to the obstacles on the left and right of the traveling assembly 1. On the other hand, the remaining ultrasonic sensors 3c and 3d are provided on both sides of the front end of the traveling assembly body 11, and the optical sensors 4a to 4d are provided in the center of the front end, and these sensors 3c, 3d and 4a to 4d. Measures the distance to the obstacle in front of the traveling assembly 1.

Optical sensors 4a-4d:
The first optical sensor 4a is provided at the top of the center in the left-right direction X of the robot. The first optical sensor 4a measures the distance Dc (FIG. 7) to the obstacle W ahead.
On the left and right sides of the first optical sensor 4a, second optical sensors 4b and 4c are provided close to the first optical sensor 4a. The second optical sensors 4b and 4c measure the distances Dr and Dl (FIG. 7) to the obstacles W diagonally forward on the left and right.
The third optical sensor 4d is provided above the first optical sensor 4a. The third optical sensor 4d measures a distance Dd (FIG. 1) to the front obliquely lower side.

  A protective cover 12 is provided at the top of the main body 11 of the traveling assembly 1 shown in FIG. As shown in FIG. 3, a recess 13 is formed in the protective cover 12. As shown in FIG. 4, the concave portion 13 includes side surfaces 13 a to 13 c that are close to and face the three sensors of the first and second optical sensors 4 a to 4 c. On the other hand, a ceiling surface 13d is formed in the recess 13, and the third optical sensor 4d is disposed at a position facing the ceiling surface 13d.

Control unit:
As shown in FIG. 5, the control unit 8 includes traveling wheel control means 41, slide control means 42, optical sensor control means 43, microcomputer (microcomputer) 44, ultrasonic sensor control means 49, and blower motor control means 50. ing.
Each means 41-43, 49, 50 is connected to the microcomputer 44 via an interface (not shown). The microcomputer 44 includes a CPU 46, a RAM 47 and a ROM 48. In the ROM 48, a traveling pattern of the traveling assembly 1, a first threshold value SHc, a stop distance Dr0, various arithmetic expressions, and the like, which will be described later, are stored in advance.

The traveling wheel control means 41 controls the traveling of the traveling assembly 1 by controlling the rotation of the drive motors 5a and 5b in FIG.
The slide control means 42 controls the rotation of the slide drive motor 15 and controls the moving mechanism of the work assembly 2.
The optical sensor control means 43 and the ultrasonic sensor control means 49 control the optical sensors 4a to 4d and the ultrasonic sensors 3a to 3d, respectively.

  The CPU (first discrimination means) 46 discriminates the approach of the obstacle W by comparing the first measurement distance Dc to the obstacle W measured by the first optical sensor 4a and a predetermined first threshold value SHc. First discrimination is performed. Further, the CPU (second discrimination means) 46 compares the second measured distance Dr (Dl) to the obstacle W measured by the second optical sensor 4b (4c) with the second threshold value SHr, thereby comparing the obstacle. A second determination for determining the approach of W is performed.

  The CPU 46 determines that the robot has approached the obstacle when it is determined that one of the two determination means has approached. When the CPU 46 determines that the obstacle W has approached, the CPU 46 may perform deceleration, stop, turn, turn, reverse, etc. of the traveling assembly 1, or a plurality of these may be combined to form the obstacle W You may avoid a collision. Alternatively, the vehicle may decelerate and travel along the wall.

Obstacle W detection principle:
Next, the principle of detecting the obstacle W according to the present invention will be described.
As shown in FIGS. 7C and 7D, when the inclination angle θ of the obstacle W is large, the side portion at the front end of the traveling assembly 1 is obstructed only by the first determination by the first optical sensor 4a. There is a risk of collision with the object W. Therefore, in this robot, the first determination or the second determination is adopted according to the inclination angle θ so that it can be determined whether or not the obstacle W has approached regardless of the inclination angle θ. Yes.
That is, when the inclination angle θ is smaller than the predetermined reference angle, the determination result of the first determination means is used to determine whether or not the obstacle W has approached. On the other hand, when the inclination angle θ is larger than the reference angle, the determination result of the second determination means is used to determine whether or not the obstacle W has approached.

For example, in this embodiment, the reference angle has the following value.
As shown in FIG. 6, the light (parallel light) from the first optical sensor 4a is irradiated substantially in parallel to the steady traveling direction F of the robot.

  On the other hand, the light irradiation directions from the second optical sensors 4b and 4c on both sides are set to predetermined attachment angles α and α, respectively, with respect to the light irradiation direction from the first optical sensor 4a. Therefore, when the inclination angle θ of the obstacle W becomes ½ of the mounting angle α, the first measurement distance Dc of the first optical sensor 4a and the second measurement of the second optical sensor 4b (4c). The distance Dr (Dl) matches.

  In this embodiment, when the inclination angle θ is smaller than the reference angle with ½ of the mounting angle α as a reference angle, that is, when the first measurement distance Dc is smaller than the second measurement distance Dr (for example, In FIG. 7A, it is determined whether or not the obstacle W has approached based on the determination result of the first determination. When the inclination angle θ is smaller than the reference angle (when Dc <Dr), the CPU 46 detects the approach of the first determination unit before the second determination unit, so the first measurement distance Dc is the first measurement distance Dc. If the threshold value SHc or less, it is determined that the obstacle W has approached.

On the other hand, when the inclination angle θ is greater than or equal to the reference angle, that is, when the first measurement distance Dc is greater than or equal to the second measurement distance Dr (for example, FIGS. 7B to 7D), the second discrimination means Since the approach is detected before the first discriminating means, it is determined whether or not the obstacle W has approached based on the discrimination result by the second discrimination.
Here, if the second threshold value SHr is set to a fixed value, both sides of the front end may collide with the obstacle W in the case of FIG. 7D where the inclination angle θ of the obstacle W is extremely large. Arise. Therefore, the second threshold value SHr is preferably increased as the inclination angle θ in FIG. 6 increases. Therefore, as described below, the value of the second threshold value SHr is increased as the inclination angle θ of the obstacle W increases.

Hereinafter, a method of changing the second threshold value SHr when the inclination angle θ is equal to or larger than the reference angle (when Dc ≧ Dr) will be described.
As a method of changing the second threshold value SHr, the second threshold value SHr may be changed according to the ratio or difference between the first measurement distance Dc and the second measurement distance Dr. For example, when Dc−Dr is large, the second threshold value SHr may be increased according to the magnitude of the difference. Further, when Dc / Dr is large, the second threshold value SHr may be increased according to the ratio.

Hereinafter, as a method for changing the second threshold SHr, a case where the difference between the first measurement distance Dc and the second measurement distance Dr is used will be described as an example.
The CPU 46 calculates the second threshold value SHr using the following equation (1).
SHr = Dr0− (Dr−Dc) (1)
Here, Dr0 is a running stop reference value of Dr when Dr = Dc, and is a value set in advance based on the sensor arrangement and the size and shape of the robot.

The CPU 46 calculates the second threshold value SHr based on the equation (1) and compares it with the second measurement distance Dr.
For example, as shown in FIG. 7B, in the case of Dr = Dc (when the inclination angle θ of the obstacle W is ½ of the mounting angle α), the second threshold value SHr is the running stop reference value. It matches Dr0.

On the other hand, as shown in FIG. 7C, when the inclination angle θ of the obstacle W is larger than α / 2, since Dr <Dc, the value of the second threshold value SHr is obtained from the above equation (1). Is set to a value larger than the travel stop reference value Dr0.
Furthermore, as shown in FIG. 7 (d), when the inclination angle θ of the obstacle W is remarkably large, Dr << Dc. Therefore, the value of the second threshold value SHr is a larger value according to the above equation (1). Set to
The CPU 46 compares the second measurement distance Dr with the second threshold value SHr, and determines that the obstacle W has approached when the second measurement distance Dr is equal to or less than the second threshold value SHr.

  As described above, when the inclination angle θ of the obstacle W is larger than the reference angle, the second threshold value SHr is increased based on the predetermined arithmetic expression so that the value of the second threshold value SHr increases as the inclination angle θ increases. The value of the threshold value SHr is changed. Therefore, even if the inclination angle θ is extremely large, the obstacle W can be reliably detected before the side portion of the front end of the robot contacts the obstacle W.

  Various calculation formulas are conceivable as calculation formulas for the second threshold value SHr depending on the shape and size of the robot, the traveling speed, and the like. In addition to the formula (1) described above, for example, SHr = Dr0− (Dr−Dc) / 2 may be used.

In the above-described embodiment, when the inclination angle θ is large, whether or not the obstacle W has approached is determined based on the determination result by the second determining means. A method is also conceivable in which the first threshold SHc is increased as the inclination angle θ of the obstacle W increases as a result of the determination by the first determination means.
As an arithmetic expression used in such a modification, for example, the following expression (2) may be used.
SHc = DR0− (Dr−Dc) × 1.5 (2)
Therefore, as shown in FIGS. 7B to 7D, the first threshold SHc increases as the inclination angle θ of the obstacle W increases, so even if the inclination angle θ of the obstacle W is large. The approach of the obstacle W can be detected using the discrimination by the first discrimination means.

  However, since the distance sensor generally improves the measurement accuracy as the measurement distance is smaller, generally, the second determination with a smaller measurement distance is performed when the inclination angle is large as in the present embodiment. It is preferable to use means. However, depending on the type of distance sensor, the measurement accuracy may be reduced below a predetermined distance. In such a case, the determination is always performed by the first determination means, and as the inclination angle of the obstacle decreases, It is preferable to adopt a method of increasing the first threshold value SHc.

As described above, the preferred embodiments have been described with reference to the drawings. However, those skilled in the art will readily understand various changes and modifications within the obvious scope by looking at the present specification.
For example, the first and second optical sensors (distance sensors) may be provided on the side of the front surface of the work robot. In such a case, the second optical sensor may be only one that measures the diagonally forward distance outside the robot body.
Accordingly, such changes and modifications are to be construed as within the scope of the present invention as defined by the claims.

It is a schematic perspective view which shows the self-propelled working robot concerning one Example of this invention. It is a plane sectional view of this work robot. (A)-(d) is a top view which shows a protective cover, side sectional drawing, a front view, and a right view, respectively. It is a perspective view which shows arrangement | positioning of a protective cover and a distance sensor. It is a schematic block diagram which shows a control means. It is a schematic diagram which shows the detection principle of an obstruction. It is a schematic plan view which shows the detection method of an obstruction.

Explanation of symbols

3a to 3d: Ultrasonic sensor (ultrasonic distance sensor)
4a: first optical sensor (first distance sensor)
4b, 4c: second optical sensor (second distance sensor)
4d: Third optical sensor (third distance sensor)
12: Protective cover 13: Recess 46: CPU (first and second determining means, changing means)
Dc: first measurement distance Dr: second measurement distance SHc: first threshold value SHr: second threshold value W: obstacle θ: inclination angle

Claims (5)

In a self-propelled working robot having a first distance sensor that measures a distance to an obstacle ahead and a second distance sensor that measures a distance to an obstacle ahead obliquely,
First determination means for comparing the first measurement distance to the obstacle measured by the first distance sensor and a predetermined first threshold to determine the approach of the obstacle;
A second determination means for determining the approach of the obstacle by comparing the second measurement distance to the obstacle measured by the second distance sensor and a predetermined second threshold;
Based on information about an inclination angle of the obstacle obtained from the first and second measurement distances, which is formed by an angle formed by a normal line orthogonal to the obstacle surface and a light emission direction of the first distance sensor. Changing means for changing the first or second threshold ,
A self-propelled work robot in which the changing means sets the first or second threshold value such that the first or second threshold value increases as the tilt angle increases.   2. The determination result as to whether or not the obstacle has approached by the first determination unit and the determination as to whether or not the obstacle has approached by the second determination unit regardless of the inclination angle. A self-propelled working robot that obtains a result and determines that the robot has approached the obstacle when it is determined that one of the two determination results has approached. The tilt according to claim 1 or 2 , based on the arrangement of the first and second distance sensors, the light emission direction from the first and second distance sensors, and the first and second measurement distances. A self-propelled working robot that can obtain information about corners. In any one of claims 1 to 3, wherein the first and second distance sensor comprises a distance sensor of optical type,
The first distance sensor is provided at the top of the left and right center of the robot,
The second distance sensor is provided a pair on both sides of the first distance sensor,
In addition to the optical first and second distance sensors, a self-propelled operation in which ultrasonic distance sensors for measuring the distance to obstacles ahead are provided on both sides of the front end of the self-propelled robot. robot. In any one of claims 1 to 3, wherein the first and second distance sensor comprises a distance sensor of optical type,
The first distance sensor is provided at the top of the left and right center of the robot,
The second distance sensor is provided a pair on both sides of the first distance sensor,
A protective cover is provided at the head portion of the robot, and the protective cover has a concave portion having three side surfaces and a ceiling surface that the three sensors are in close proximity to, and
A self-propelled working robot in which a third distance sensor for measuring a distance to a diagonally downward front is disposed at an inner position facing the ceiling surface.

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