JPH04147084A - Apparatus for detecting obstacle of self-running work robot - Google Patents

Abstract

PURPOSE:To enable determination also of a status of a light receiving surface by providing a first microprocessing system circuit for controlling a laser light distance sensor and a second microprocessing system circuit for controlling a supersonic distance sensor. CONSTITUTION:A supersonic driver 26 actuates a wave transmitter 27 with wave transmission time of length corresponding to a distance of an obstacle which is already detected by a laser light sensor 2, stops the wave transmitter 27 and enables a wave receiver 28 to receive waves to wait for arrival of reflected waves. When the reflected waves arrive, a timer counter 29 stops counting and transmits the count to an MPU system circuit B32 via an interface 31. The circuit 32 calculates required time from the counted value and obtains a distance to the obstacle with temperature compensation. Two supersonic sensors are placed on a front face of a robot and they can be rotated almost to 90 deg., so that even an obstacle forming an edge on the front can be detected if it spreads over a measured surface. Inclination sensors 44, 45 in proceeding and lateral directions measure a gradient angle of the robot and inform it of a measurement controller 25 respectively.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention is applicable to robots such as floor cleaning robots where the work place is not fixed, and therefore the guiding means such as the guiding cable is constantly connected. This invention relates to an obstacle detection device for a self-propelled working robot that is used in locations where the location of obstacles cannot be installed and where the location of obstacles changes over time.

(Prior technology) For example, a floor cleaning robot uses encoders installed on its wheels to measure the distance it has traveled, uses a built-in gyro to detect its own position, and uses a microcomputer to control its own position. The vehicle automatically travels along a reference course that has been created, and then uses, for example, an ultrasonic sensor to detect obstacles while checking the route, and if an obstacle is found, it avoids it.

However, ultrasound can only detect relatively short distances (
(several centimeters to several metres) and the obstacle faces directly. Depending on the direction and shape of the obstacle, it may not be possible to detect it. In this case, the robot may move the object that cannot be detected to a location outside of the floor cleaning area. It is necessary to move the device in advance or to surround it with plywood, cardboard, etc. to make it possible for ultrasonic detection.

In addition, since inspection is limited to obstacles at short distances, it is difficult to grasp the positional relationship of obstacles in the workplace, and it is difficult to grasp the general condition of obstacles scattered in the workplace in advance.

On the other hand, there is a method that uses light to detect obstacles, but in this case it is difficult to detect obstacles because the light is not reflected by transparent objects such as glass. There is also a method of image detection using a CCD camera or a stereo camera, but image processing and coordinate transformation are complicated, and detection takes time and requires expensive equipment.

(Problems to be Solved by the Invention) As mentioned above, automatic traveling work robots equipped with ultrasonic sensors used in places where the work place is not always fixed, such as floor cleaning robots, have a short detectable distance for obstacles. write,
Additionally, there are problems in that it is difficult to detect the corners of objects, and it is not possible to set the robot's travel route taking into account even distant obstacles.Furthermore, when using light, the measurement accuracy at short distances is low, and There is a problem in that it cannot detect glass surfaces through which light passes.

The present invention provides a highly reliable obstacle detection device for a self-propelled working robot that can expand the detection range of obstacles and also determine the condition of the light-receiving surface of the obstacle to reliably detect the obstacle. The purpose is to

[Structure of the invention]

(Means and effects for solving the problem) The present invention projects a laser beam in a commanded target direction through a cross-shaped slit, receives reflected light from an obstacle of the laser beam, and creates a cross-shaped image of the received light. A laser beam distance sensor that measures the distance to an obstacle through arithmetic processing based on the length of A first microprocessor system circuit that creates an obstacle map from distance information, and a system that projects ultrasonic waves in a commanded target direction and measures the distance to the obstacle from the time required to receive the reflected ultrasonic waves. An obstacle detection device for an automatic working robot, comprising an ultrasonic distance sensor and a second microprocessor system circuit that controls the ultrasonic distance sensor according to commands from a measurement control device and information on the obstacle map. By utilizing the respective advantages of laser light and ultrasonic waves, a relatively simple device is used to enable a self-propelled working robot with an unfixed running path to safely drive while avoiding obstacles.

(Example) An example of the present invention is shown in FIGS. 1 and 2. That is, FIG. 1 is a side view showing an example of a self-blade traveling work robot equipped with a laser beam distance sensor and an ultrasonic distance sensor according to the present invention, and FIG. 2 is a side view showing an example of an obstacle detection device according to the present invention. It is a block diagram.

In FIG. 1, an automatic traveling type work robot 1 has at least one laser beam distance sensor 2 installed on the upper front side.
For example, sensor 2 is 150' in the vertical direction and 180' in the horizontal direction.
degree and can rotate 360 degrees around the direction of travel. The laser light sensor 2 is in charge of detecting obstacles to the light reflector from the side to the front.

In addition, a total of eight ultrasonic distance sensors 3 are installed, two each on the front, both sides, and under the back of the robot 1, to detect obstacles relatively close to the robot 1 by reflecting sound. The direction of the wave transmission and reception can be changed vertically and horizontally.

As shown in FIG. 2, the laser light distance sensor 2 has a laser light driver 4 that decodes the command transmitted through the interface A13 and turns on and off the laser light source 5, and the laser light driver 4 turns on and off the laser light source 5. A laser beam 6 is passed through a cross-shaped slit 7, and a cross-shaped slit-shaped laser beam 8 is projected forward.

The sensor 2 further includes a lens 10 with a filter that allows the reflected light 9 of the cross-shaped slit-shaped laser light to pass through, a two-dimensional CCD image sensor 11 that receives this light, and an image sensor driver 12 that processes this image signal. The output signal is passed through the interface A13 to MP
The image length information is transmitted to the U system circuit A14 as the length of the image, and the circuit A14 is configured to issue a command to the image sensor driver 12 via the interface A13.

Note that the MPU system circuit A14 is connected to the memory A15 so that information can be transmitted bidirectionally. Also, interface A is used to orient sensor 2 in the required direction.
A motor driver 16, 19, 22 is connected to the motor driver 13, a vertical rotation motor 17 is connected to the driver 16, and a rotation angle detector 18 is connected to the motor 17 to control the vertical rotation angle by one rotation angle feedback. are doing.

Similarly, a motor driver 19, a left-right rotation motor 20,
The rotation angle detector 21 and the interface A13 are used to control the left and right turning angle, and the motor driver 22
The rotation angle is controlled using the optical axis rotation motor 231, rotation detector 24, and interface A13.

In addition, the MPU system circuit 14 is connected to the interface A13.
Ultrasonic sensors 3B, 3C,..., 3I interface C42,..., interface I43 via
It is bidirectionally connected to the measurement control device 25 via the interface A13.

The ultrasonic distance sensor 3, as shown in representative example 3B,
Measurement control device 25 that is a command source and interface B31
The interface B31 is further bidirectionally connected to an MPU system circuit B32 which is the center of measurement data processing of the sensor 3B, and the MPU system circuit B32 is further bidirectionally connected to a memory B34.

The ultrasonic sensor 3B includes an ultrasonic driver 26 that turns on and off ultrasonic waves, a transmitter 27 that outputs ultrasonic waves 30, a receiver 28 that receives reflected ultrasonic waves 30, and from the start of wave transmission to the start of wave reception. It consists of a time counter 29 for counting the time, and a thermometer 33 for temperature-correcting the speed of sound. In addition, the interface B31 is the time counter 2.
9 and a thermometer 833, respectively.

Further, in order to arbitrarily change the direction of wave transmission and reception of the ultrasonic sensor 3B, a motor driver 35, a vertical rotation motor 36, and a rotation angle detector 37 are provided.Similarly, a motor driver 38,
A left/right rotation motor 39 and a rotation angle detector 40 are provided, and are connected to the MPU system circuit B32 via an interface B31 to enable rotation angle feedback control.

In addition, since the running floor surface is not necessarily horizontal, a traveling direction inclination angle sensor 44 and a left-right direction inclination angle sensor 45 are provided and are bidirectionally connected to the measurement control device 25, and furthermore, the measurement control device 25 is connected to the travel control device 46. Both are connected in both directions.

When the self-driving work robot 1 is operated slowly while working, the measurement control device 25 issues measurement commands to the laser beam distance sensor 2 and the ultrasonic distance sensor 3, respectively.

As a result, a measurement command is issued to the laser light driver 4 and the MPU system circuit A14 via the interface A13, and the driver 4 turns on the laser power to light up the laser light source 5, and the output laser light 6 is sent to the cross-shaped slit. 7, becomes a cross-shaped slit-shaped laser beam 8 with a - side length L, and is projected in the direction of the obstacle.

When this laser beam 8 is projected perpendicularly onto a vertical planar wall surface 41 located at a distance r, the length of an image formed on the two-dimensional CCD image sensor 11 at a reference distance rH is shown in FIG. The length of the image is Q for the length QR.

In other words, the spread of the laser beam 8 is δ=0.2+s rad
Then, the length R of one side of the cross-shaped slit light formed on the reference wall surface at the reference distance rR is the spread at rR as △LR=δ"l"H:2 =L+ΔLR:L+2X10-'rR
becomes.

When the reflected light 9 from the reference wall passes through the filtered lens 10, only the light whose wavelength matches that of the laser beam 8 is selectively passed through, creating an image of length QR on the surface of the two-dimensional COD image sensor 11, which is This is due to the fact that the focal point of the lens 10 is at a distance rc from the surface of the sensor 11.

The length L' of one side of the image created by the laser beam 8 on the wall surface 41 at an arbitrary distance r is the spread ΔL=δ・r=2×1
Since it becomes 0-'r, L'=L+ΔL=L+2X10-'
r, and the length l of the image that the reflected light 9 forms on the surface of the sensor 11 is given by the following ω formula.

If the above equation 0 is rewritten as the relationship between Q and r, r = L
/ (-!!-・凰-δ) ... ■RrR, where QRy rRv LRt δ, L are known values, so by measuring Q and calculating the formula 0, the distance r is required.

In order to obtain the distance r in this way, the image of the two-dimensional CCD image sensor 11 is sent to the image signal processing section of the image sensor driver 12, the length Ω is determined from the coordinates of both ends of the image, and the image is sent to the MPU via the interface A13. 6, which is sent to the system circuit A14 and stored in the memory A15;
rR+LRtδ,L is called to circuit A14 and calculation of equation 0 is performed.

On the other hand, the coordinate values determined from the travel record recorded in the travel control device 46 via the mileage meter 47 provided on the wheel are transmitted from the measurement control device 25 to the MPU system circuit A14, and the coordinate values and the direction of measurement are transmitted from the measurement control device 25 to the MPU system circuit A14. The distance r is stored in the memory A15 and also transmitted to the measurement control device 125 at the same time, and a map is drawn in the circuit A14 after understanding the boundaries of the work area and the arrangement and shape of the pillars within the work area. The user then plans a work route, and further corrects the map using relatively nearby information from an ultrasonic sensor 3, which will be described later, to correct the work route and continue the work.

When the laser beam 8 is projected perpendicularly onto the vertical planar wall surface described in FIG. Both are projected on the top with length Q. If the lengths of both sides are the same in this way, it can be seen that the reflecting surface is a vertical planar wall surface. however.

This is limited to cases where the robot 1 itself is on a horizontal floor surface.

The MPU system circuit A14 also gives a command to the motor driver 16 to control the vertical rotation motor 17 from the rotation angle detector 18.
The vehicle is rotated until the angle θ detected by the angle θ matches the command value θ issued to the driver 16.

Figure 4 shows a vertical wall surface 4 at an elevation angle θ from a position at a horizontal distance rf.
1, the distance between the sensor 2 and the projection surface is r=rf' se
Since the laser beam is projected at an angle of θ, the vertical image length is LfV=(L+δ・r)se
eθ, the length of the image in the horizontal direction is Lfv=L + δ·r. Therefore, Qfv/Qfh=Lfv/L(h=sec
θ is determined by the MPU system circuit A14 from the relationship between θ.

If the reflecting surface is curved with a certain curvature or is cylindrical, the image will be straight in the vertical direction, but in the horizontal direction it will only appear to be a straight line when viewed from directly in front, and the elevation angle θ The larger the image, the more the horizontal image will appear to be curved.

Fig. 5 shows an angle φ on the right side, although it is horizontal to the vertical wall surface 41.
This shows the case where the image is projected with a deviation of 1. The length of the image in the vertical direction is L5v=L+δ・r, but the length of the image in the horizontal direction is Lsh=(L+δ・r)seeφ. Also, as in the case of Fig. 4, Qsv / Q in circuit A14
φ is determined from sh = Lsv/LSh = cosφ. In this case, the driver 19.
A motor 20 and a detector 21 are used.

In this way, one short side of the cross shape of the laser light sensor 2 has information on the distance r, and the other long side has information on the state of the reflecting surface. If the reflective surface is a flat surface, both sides are straight lines, and it is only necessary to know the position coordinates of both ends of the straight line, so image processing by the driver 12 can be performed easily and quickly. However, it can be easily detected up to 20 to 30 meters from the vicinity of the robot 1. Furthermore, since the vehicle does not immediately collide with a distant obstacle, the accuracy of the distance r does not need to be very high. Obstacles in the diagonal direction are motor 22, motor 23 . Using the detector 24, the cross-shaped laser beam 8 is appropriately moved in an oblique direction to make the images coincide.

The ultrasonic distance sensor 3 is used to detect transparent obstacles and to measure distances with high precision at close range of obstacles previously detected by the laser light sensor 2.

First, when a command to operate the ultrasonic sensor 3B is issued from the measurement control device 25 to the ultrasonic driver 26 and the MPU system circuit B32 via the interface B31, the driver 26 operates the transmitter 27 having a concave vibrator. A focused ultrasonic wave 30 is transmitted. At the same time, the driver 26 notifies the time counter 29 of the wave transmission time of the wave transmitter 27, and starts the time count of the counter 29.

When measuring the distance of an obstacle that has already been detected by the laser light sensor 2, the driver 26 operates the transmitter 27 with a transmission time of a length corresponding to this (short time when nearby, long time when far).
After stopping the wave transmitter 27, the wave receiver 28 is placed in a receiving state and waits for the arrival of the reflected wave.

When the reflected wave arrives, the counter 29 stops counting and transmits the count value to the MPU system circuit B32 via the interface 31. At the same time, the temperature T in the air is transmitted from the thermometer 833 to the circuit B32, and in the first circuit B32, the required time t is calculated from this count value, and the time t is calculated as the product of the speed of sound in the air, 97, corrected by the temperature T, and the time t/2. Find the distance S to 5=yT-t/2.

This result is reported to the measurement control device [125] along with the coordinates and direction of the measurement position, and is stored in the memory B34. Further, a command is issued from the circuit B32 to the motor drivers 35 and 38 to direct the sensor 3B in the required direction.
The vertical rotation motor 36 and the left and right rotation motor B39 are operated, the amount of operation is detected and checked by the detectors 37 and 40, and the sensor 3B is directed in a desired direction. In measuring the distance, the transmission time of the transmitter 27 is selected to be shorter than the time required for the ultrasonic wave 30 to travel back and forth over a set distance.

Sensors 3B and 30 are installed on the front of the robot 1, and it can turn up to nearly 90'', so even if there is an obstacle that forms an edge in front, if there is a spread on the side, its presence can be detected by detecting the side. .Detection of obstacles on the side of robot 1,
Obstacle detection when reversing can also be done in the same way.

The forward direction and left/right direction inclination angle sensors 44 and 45 measure the inclination angle of the robot l according to commands from the measurement control device 125, and notify the respective devices 25 of the inclination angle. Tilt angle sensor 44
．． 45, for example, magnetoresistive elements are arranged in a disk shape,
When a magnetic field from a semicircular magnet is applied to the element using a three-terminal element with an intermediate electrode removed, a rotary potentiometer can be used that can obtain an increase in magnetic resistance corresponding to the position of the magnet.

As described above, the state of the reflective surface can be estimated from the image formed on the reflective surface by the cross-shaped slit light 8 of the sensor 2.

For example, if it is a curved surface, one side will be a curved image. If there are two straight slit images, the length of the shorter one is relevant for distance measurement, and if the slit image consists of one curved line and one straight line, the length of the straight line is relevant for distance measurement. related, reference distance r
The distance r can be measured with reference to l and the slit sight QR on the image sensor 11. Furthermore, the angle between the reflecting surface and the projection surface of the sensor can be determined from the ratio of the lengths of the slit images. In the case of a curved line, the curvature can be estimated from the relationship between the degree of curvature, the posture of the robot 1, and the projection angle. Angles from two different points whose coordinates are known for the same characteristic measurement object and robot 1
Since there is an angle of inclination related to the attitude of , the distance r can be determined and checked using the principle of triangulation.

Furthermore, by using ultrasonic waves in combination, even transparent obstacles can be detected 2 to 3 meters in front of the robot 1.

Even when measuring a specific position in an obstacle using the ultrasonic sensor 3, the distance r can be determined and checked using the principle of triangulation from two or more coordinate values and the angle of the measurement direction. You can create a slightly larger map using sensor 2, create a work plan, and use sensor 3 to refine this map while making corrections to the work.

Furthermore, since the method is based on finding the coordinates of the end points of the cross-shaped slit 8, image processing can be performed easily and quickly.

In the above embodiment, the laser light sensor 2 uses a cross-shaped slit-shaped laser beam 8, but if the work robot 1 moves very slowly, a simple linear-shaped slit-shaped laser beam can be used. , after the - degree detection is completed, it may be rotated 90' and detected again using the --shaped slit-shaped laser beam.

In addition, the two-dimensional CCD image sensor 11 is
It is also possible to replace it with an image sensor and move a -dimensional sensor by the width of the sensor 11.If the speed is not extremely slow but you can stop occasionally, when you stop, you can move the surrounding obstacles through a linear slit. A similar effect can be obtained by a combination of 90'' rotation of the shaped laser beam or by moving the one-dimensional COD image sensor in the width direction by an amount equivalent to the lens field of view. It can also be placed anywhere and rotated 360 degrees horizontally.

〔Effect of the invention〕

As explained above, according to the present invention, since laser light and ultrasonic waves are combined to utilize their mutual advantages, it is possible to widen the detection range of obstacles, and the accuracy is improved even at long distances. High accuracy can be achieved in the vicinity even when the distance is low, and since a cross-shaped slit image is used, image processing is easy and quick.Furthermore, the state of the reflective surface of obstacles can be seen, and transparent objects and edges can be detected. A rational obstacle detection device for a self-propelled working robot that can also detect objects can be obtained.

[Brief explanation of drawings]

Fig. 1 is a side view of an automatically traveling work robot showing an embodiment of the present invention, Fig. 2 is a system diagram showing the configuration of the obstacle detection device of the work robot shown in Fig. 1, and Fig. 3 is a diagram showing the reference distance and An explanatory diagram showing the relationship between the received light image on the reflective surface and the image on the sensor at an arbitrary distance. Figure 4 is an explanatory diagram when the light is incident at an elevation angle θ. Figure 5 is an explanatory diagram when the light is incident at a horizontal deflection angle φ. It is an explanatory diagram. 1... Automatic traveling type work robot 2... Laser light distance sensor 3... Ultrasonic distance sensor 4... Laser light driver 5... Laser light source 6, 8... Laser light 7.
...Cross-shaped slit 9...Reflected light 10...Lens with filter 11...Two-dimensional CCD image sensor 12...Image sensor driver 13, 31.42.43...Interface 14, 3
2...MPU system circuit 15, 34...Memory 16, 19.22.35.38...Motor driver 1
7, 20.23.36.39...Swivel motor 18, 2
1.24.37.40... Rotation angle detector 26... Ultrasonic driver 27... Transmitter 28... Receiver
29...Time counter 30...Ultrasonic wave
33...Thermometer 41...Wall surface
44.45... Tilt angle sensor 46... Travel control device 47... Odometer (8733) agent
Patent attorney Yoshiaki Inomata (and 1 other person)

Claims (1)

[Claims] A laser beam is projected in the specified target direction through a cross-shaped slit, the reflected light of the laser beam from an obstacle is received, and the distance to the obstacle is measured by calculation processing based on the length of the received cross-shaped image. a first microprocessor system circuit that controls the laser distance sensor according to commands from the measurement control device and creates an obstacle map from distance information obtained in response to various target directions; , an ultrasonic distance sensor that projects ultrasonic waves in a commanded target direction and measures the distance to the obstacle based on the time required to receive the reflected ultrasonic waves, and a command from the measurement control device and the above-mentioned obstacle. An obstacle detection device for a self-propelled working robot, comprising a second microprocessor system circuit that controls the ultrasonic distance sensor according to information on an object map.