JP2002144278A - Legged mobile robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a legged mobile robot having a manipulator, capable of executing the measurement without interfered by the manipulator, and constantly detecting peripheral objects, particularly, an object at a lower side in a proper state to measure a distance or the like. SOLUTION: This humanoid robot 21 is composed of upper arm parts 22a, lower arm parts 22b, hand parts 22c, a waist part 24 and leg parts 25, and moves with high degree of freedom by the rotation on rotating shafts 31-34 of revolute joints, or the like. The manipulator is composed of the upper arm parts 22a, the lower arm parts 22b, the hand parts 22c and the like. An external sensor 27 provided with a luminescent means for applying the multi-slit light to a floor face 20 or the like, and an image pick-up means for picking up an image of the irradiated floor face, is mounted on the waist part 24. As the external sensor 27 can detect the floor face 20 without interfered by the manipulator, the distance to the floor face and the shape of the floor face can be stably measured at all time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a legged mobile robot having a manipulator, and more particularly, to a head, an arm,
The present invention relates to a humanoid legged mobile robot including a torso, a waist, and legs.

[0002]

2. Description of the Related Art A self-standing mobile robot is provided with a device for detecting a floor surface, a wall surface, an obstacle or the like when moving. For example, Japanese Patent Application Laid-Open No. 6-43935 discloses a means for irradiating a predetermined pattern of slit light that intersects the traveling direction, a means for imaging a portion irradiated by the slit light, and an analysis of the pattern of the imaged slit light. And a means for determining the presence or absence of an obstacle ahead in the traveling direction. Also, JP-A-6-8344
In Japanese Patent Application Laid-Open Publication No. 2000-209, three-dimensional coordinate data is calculated based on a light-section line formed on the surface of an obstacle by irradiating slit light using a light-section method, and the robot travels based on the three-dimensional coordinate data. Is disclosed.

In a conventional bipedal walking robot, a walking pattern is determined on the premise that the height and inclination of the floor surface are known. In addition, a slight height estimation error is absorbed by the compliance control so that the robot can walk without falling. Also, if the floor cannot be measured in advance, if the walking path cannot be corrected accurately, or if an unknown obstacle appears, compliance control alone is not sufficient and leads to a fall. Biped robots with external sensors have also been studied. In a humanoid robot having legs and arms, the external sensor as described above is provided on the head.

[0004]

However, when an external sensor of a robot equipped with a manipulator, particularly a humanoid robot is provided on the head, there are the following problems.

[0005] The first problem is the interference of the manipulator with external sensors. For example, when trying to measure the floor surface in the moving direction, a light source provided on the head illuminates the floor surface in front, but if the irradiation light is blocked by the manipulator, there is not enough floor space. Cannot illuminate the area. Further, for example, when the humanoid robot moves while holding a large luggage on its arm, the irradiation light is blocked over a wide range.

[0006] The second problem is the orientation of the external sensor. In a humanoid robot, the head may be tilted in the front-rear direction or the left-right direction or the direction of the head may be changed by the movement of the neck joint. Further, there is a case where the upper body of the robot is tilted or changed in the front-rear direction or the left-right direction depending on the movement of the trunk portion. Since the direction of the external sensor provided on the head is changed by these movements, it is not always possible to always properly detect the state of the floor in front.

The present invention has been made in view of the above circumstances, and even in a robot having a manipulator, the manipulator does not interfere with the measurement and always keeps the surrounding objects, particularly the lower objects, in an appropriate state. It is an object of the present invention to provide a legged mobile robot capable of detecting distance and measuring a distance.

Particularly, in a humanoid legged mobile robot including a head, a torso, an arm, and a leg, the arm does not interfere with the measurement and is always good even when each joint is moved. It is an object of the present invention to provide a legged mobile robot capable of detecting a floor surface, a wall surface, an obstacle, and the like in a traveling direction and measuring a distance.

[0009]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is directed to a leg connected to a main body for movement, and to a main body connected to the main body for moving an object in space. A manipulator, wherein a connecting portion between the manipulator and the main body is disposed above a connecting portion between the leg portion and the main body, wherein the manipulator and the main body are connected to each other. The gist of the present invention is a legged mobile robot including an external sensor that detects an object to be measured, below a joint and above a joint between the leg and the main body.

Further, the legged mobile robot of the present invention is a humanoid robot having a waist, and the external sensor is arranged at or around the waist.

Further, in the legged mobile robot according to the present invention, the external sensor includes a light emitting means for irradiating slit light and an image pickup means for imaging a light cutting line formed on the object to be measured by the slit light. It is characterized by having.

Further, the legged mobile robot according to the present invention is characterized in that the legged mobile robot is provided with distance calculating means for calculating a distance to the object to be measured based on an image taken by the image taking means.

Further, the legged mobile robot according to the present invention is characterized in that it is provided with leg control means for controlling the movement of the leg based on the information on the distance calculated by the distance calculation means.

Further, the legged mobile robot of the present invention is characterized in that the surroundings are monitored by using a light section method based on the image picked up by the image pickup means.

Further, in the legged mobile robot of the present invention, the imaging means is constituted by at least two cameras, and associates the same object in each image captured by these cameras, The distance to the object is calculated using the parallax of the obtained object.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a main configuration of the legged mobile robot according to the embodiment.
This configuration measures the distance of the floor, wall, obstacles, etc. on and around the robot's movement path as the measurement target object, and adjusts the robot's legs so that the foot landing position during bipedal walking is appropriate. Is to be controlled.

In FIG. 1, reference numeral 1 denotes a laser light source (light emitting means) for irradiating an object to be measured (a floor or the like) with multi-slit light. 2a and 2b are
They are a narrow baseline camera (imaging means) and a wide baseline camera (imaging means) for imaging the measurement target object irradiated with the slit light from the laser light source 1, respectively. The narrow baseline camera 2a is provided relatively near the laser light source 1, and the wide baseline camera 2b is provided relatively far from the laser light source 1. That is, in the present embodiment, at least two cameras are provided, and the camera and the laser light source are arranged so that the distance between the first camera and the laser light source is different from the distance between the second camera and the laser light source. I have. Also,
Reference numeral 3 denotes a light emission control unit (light emission control unit) that outputs a timing signal to the laser light source 1 to control the light emission timing of the laser light source 1 and the imaging timing of the narrow baseline camera 2a and the wide baseline camera 2b. ).

Reference numeral 4 denotes an image capturing unit which captures an image captured by the camera 2 and performs A / D conversion (analog / digital conversion) and stores it in an image memory. Reference numeral 5 denotes an image captured by the image capturing unit 4. Is a distance estimating unit (distance calculating means) that calculates the distance to the measurement target object based on the distance. Reference numeral 8 denotes a moving path determining unit that determines the moving path of the robot, and 6 determines the landing position of the robot's foot based on the path information determined by the moving path determining unit 8 and the distance calculation result by the distance estimating unit 5. A landing position determination unit 7 is a leg control unit (leg control means) that controls a motor that drives the legs of the robot while balancing the robot so as to bring the foot to the landing position determined by the landing position determination unit 6. is there.

FIG. 2 is a sectional view showing the principle of the light section method used in the present embodiment. In FIG.
Reference numeral 1 denotes a slit light source provided in the three-dimensional measuring device;
Reference numeral 903 denotes a lens for imaging provided in the three-dimensional measurement apparatus, reference numeral 903 denotes an image forming plane of an image by the lens 902, and reference numeral 905
Is the center point of the imaging plane 903, and this center point 905 is the intersection of the imaging plane 903 and the imaging direction axis. Also, 901
a is a slit light surface emitted from the slit light source 901;
910 is an object to be measured, 911 is a slit light surface 901a
Is one of the irradiation points irradiating the object to be measured.

Here, the slit light source 901 and the lens 90
The distance from the center of 2 is L (base line length). The reference line in the drawing indicates a direction perpendicular to the measurement surface (the surface perpendicular to the cross section in FIG. 6) including the line connecting the slit light source 901 and the lens 902. The angle of the slit light with respect to the measurement surface is θ, and the angle of the line connecting the center of the lens 902 and the irradiation point 911 with respect to the measurement surface is φ. Here, in order to determine the distance Z from the measurement surface to the measurement target object 910, a calculation such as the following equation may be performed.

Z = Ltan (θ) tan (φ) /
(Tan (θ) + tan (φ)) where “tan ()” represents a tangent function.

Note that φ is the imaging direction (center point 905).
Φ0 with respect to the imaging plane (in the direction connecting the lens and the center of the lens 902) and the displacement angle φ1 of the irradiation point 911 with respect to the imaging direction.
And is expressed by the following equation.

Φ = φ0 + φ1

The displacement angle φ1 is calculated by using the distance 1 between the lens 902 and the image plane 903 and the displacement Δx of the irradiation point 911 from the image center point 905 on the image plane 903.
It is expressed by the following equation.

Φ1 = arctan (Δx / l) where “arctan ()” represents an inverse tangent function.

As described above with reference to the cross-sectional view, the slit light is applied not only to the cross section but also to form a linear cutting line on the surface of the object 910 to be measured. The distance to each point on the line can be measured. In the present embodiment, since the laser light source 1 irradiates the multi-slit light, it is possible to measure the illuminated range using the light cutting line formed by each.

FIG. 3 is a side view showing the external structure of the legged mobile robot according to the present embodiment. In this figure,
Reference numeral 20 denotes a floor surface, 20a denotes a protruding surface existing on the floor surface 20, and 21 denotes a humanoid robot. The humanoid robot 21 includes an upper arm 22a, a lower arm 22b, and a hand 2
2c, trunk 23 (body), waist 24 (body), leg 25
It consists of each part. The upper arm 22a, the lower arm 22b, the hand 22c, and the joints connecting them form a multi-joint manipulator for moving an object in space.

Numerals 31 to 34 denote rotation axes of joints that connect various parts of the humanoid robot 21. For example, the upper arm 22
“a” is attached to the trunk 23 via a joint, and makes a motion about the rotation shaft 31 as shown by a broken arrow (A) in the figure. For example, when the humanoid robot 21 carries a load, it is possible to hold the load by bending the elbow joint so that the upper arm 22a and the lower arm 22b form an angle of approximately 90 degrees.

Reference numeral 27 denotes an external sensor. The external sensor 27 includes at least the laser light source 1 shown in FIG.
And a narrow base length camera 2a and a wide base length camera 2b. The laser light source 1 irradiates a multi-slit light to a range indicated by reference numeral 28, and irradiates the irradiated floor surface 20 and projection surface 20a with a narrow base line. An image is taken by one or both of the long camera 2a and the wide baseline camera 2b. Then, the distance to each light cutting line forming position is measured according to the above-described principle, the landing position of the foot is determined, and the movement of the leg is controlled.

In a humanoid robot of a normal size, the case where an external sensor is provided on the waist as shown in FIG. 3 and the case where an external sensor is provided on the head as in the prior art are:
It has been found through experiments and the like that the following differences occur.

(1) Maximum Base Line Length The base line length, that is, the distance between the slit light source and the camera is:
It can be wider when provided on the waist than when provided on the head. For example, while the maximum base line length is about 7 cm (cm) when provided on the head, it can be about 20 cm when provided on the waist.

(2) Distance to Floor The distance from the external sensor to the floor is smaller when it is provided on the waist than when it is provided on the head. For example, it is about 150 cm when provided on the head, and about 80 cm when provided on the waist.

(3) Measurement accuracy Due to the difference between the maximum base line length and the distance to the floor, higher accuracy can be obtained when the sensor is provided at the waist than at the head. For example, when performing photographing using the same type of camera and lens, the measurement accuracy of the external sensor provided on the head is about ± 55 mm (mm), whereas the measurement accuracy of the external sensor provided on the waist is The precision is about ± 5 mm, and a precision difference of 10 times or more occurs in absolute value.

(4) Necessity of Seismic Isolation / Follow-up Function In order to realize a distance measuring system of about ± 5 mm with an external sensor provided on the head, it is necessary to use a telephoto lens for imaging of a light cutting line. In order to provide a telephoto lens with a narrow angle of view on the head of a walking robot to perform stable measurement, an anti-shake function to reduce the effects of vibration caused by movement and the imaging target It is necessary to provide a following function for following the following. When an external sensor is provided on the waist, an accuracy of ± 5 mm can be achieved without adding these functions. Therefore, it is more advantageous to provide an external sensor at the waist from the viewpoint of the complexity and cost of the configuration of the robot.

(5) Field of View When an external sensor is provided on the head, a wide range of up, down, left, and right can be captured by moving a neck joint or the like. On the other hand, when an external sensor is provided on the waist, the field of view is basically only the front, and the range of the field of view is limited even when the waist can be turned left and right to some extent.

(6) Coexistence with Environment Recognition / Remote Control When an external sensor is provided on the head, it is necessary to perform processing for recognizing the operating environment of the robot and processing for measuring the distance to the floor or the like in a time sharing manner. Control becomes complicated. On the other hand, since the external sensor provided on the waist only measures the floor surface or the like, it can relatively easily coexist with environment recognition / remote control.

(7) Reflection intensity of laser light When an external sensor is provided on the head, the intensity of the laser light reflected on the floor or the like and incident on the camera is 0.29 times, whereas the intensity of the external light is When a sensor is provided, it is 3.5
It is twice. There is approximately a 12-fold gap between the two, and when an external sensor is provided on the waist, the light cutting line can be recognized more reliably and stable measurement can be performed.

(8) Concealment of floor surface by arm When an external sensor is provided on the head, a part of the floor is blocked when the arm is put forward from the trunk, so that the measurable range is reduced. Narrow. In addition, when the luggage is held by the arm or held in the hand in front of the trunk, the measurement range is further narrowed, and the measurement may not be performed at all. On the other hand, when an external sensor is provided on the waist, the floor is not concealed at all by the arms or hands, or is significantly reduced, and the floor and the like can be stably measured even during the operation of the robot. .

(9) Positioning accuracy of the waist position with respect to the floor surface When an external sensor is provided on the head, since there is a degree of freedom of movement from the waist to the head, geometric correction during this time is required. Positioning accuracy decreases. On the other hand, when an external sensor is provided on the waist, the waist and the external sensor are directly connected and are integrated during the operation of the robot, so that the positioning accuracy is high.

As described above, when the external sensor is provided on the head as in the prior art, the measurement accuracy, cost, maintenance of the measurement direction, This is advantageous in terms of the influence of concealment by the manipulator.

Next, the proper use of two cameras in this embodiment will be described. As shown in FIG. 1, the robot according to the present embodiment includes a narrow baseline camera 2a and a wide baseline camera 2b. When the angles of view of the narrow baseline camera 2a and the wide baseline camera 2b are equal to each other, the image captured by the narrow baseline camera 2a exists in a wider distance range than the image captured by the wide baseline camera 2b. An object to be measured can be captured. On the other hand, as is clear from the principle of the light section method, it is possible to perform distance measurement with higher accuracy by using an image taken by the wide baseline camera 2b than by using an image taken by the narrow baseline camera 2a. it can. That is, the narrow baseline camera 2a and the wide baseline camera 2b
It is possible to more accurately measure the distance to the object to be measured in a wider range by appropriately using. That is, for example, first, the distance to the object to be measured is measured with rough accuracy using the narrow baseline camera 2a, and the imaging direction of the wide baseline camera 2b is adjusted if necessary according to the distance measurement result. Then, the distance to the object to be measured is measured with high accuracy using the wide baseline camera 2b. This makes it possible to measure a measurement target object in a wide distance range with high accuracy.

Further, by performing binocular stereoscopic vision using these two cameras, a floor surface can be detected with high accuracy, and a distant obstacle can be detected with high accuracy.
In order to perform such binocular stereoscopic vision, for example, images captured by both cameras are respectively A / D converted (analog / digital converted) and fetched into an image memory. The same included imaging object is associated with each other, and the distance to the associated imaging object is calculated using the parallax of the object based on the principle of triangulation. The details of such measurement using binocular stereovision are described in, for example, "Vehicle Environment Recognition Apparatus" (Japanese Patent Application Laid-Open No. 9-159442) filed by the present applicant.

In the above embodiment, two cameras, the narrow base length camera 2a and the wide base length camera 2b, are used. However, the number of cameras is arbitrary, and one camera may be used. There may be three or more.

In the above embodiment, the external sensor is provided at the waist, but the external sensor is provided at an arbitrary position between the leg and the manipulator in the vertical direction, for example, around the waist, for example. You may do it. In addition, in the case of a legged mobile robot having a manipulator disposed above a leg, not limited to a humanoid robot, when an external sensor is provided at an arbitrary position between the leg and the manipulator in the vertical direction. Has the same effect.

Here, the reason why the external sensor is provided below the manipulator is to avoid interference by the manipulator when measuring the floor surface as described above. The reason why the external sensor is provided above the leg is to enable a wide range to be measured. If, for example, an external sensor is provided on the leg, the following problem will occur.

FIG. 4 is a side view showing a multi-slit light irradiation range when an external sensor is provided on the leg of the humanoid robot. In FIG. 4, reference numeral 21 denotes a humanoid robot,
40 is a floor surface, 40a is an upper surface of an obstacle existing on the floor surface 40, 40b is a side surface of the obstacle, 47 is an external sensor provided on the leg of the humanoid robot 21, and 48 is an external sensor 47 Is a multi-slit light irradiation range. As shown, in this example, since the installation position of the external sensor 47 is too low, a part of the side surface 40b of the obstacle can be measured, but the top surface 40a and the floor surface beyond the obstacle are measured. Can not do it. By restricting the measurement range in this way, the advantage of the legged robot that an obstacle having a certain height can be traversed cannot be utilized.

In addition, even when there is no obstacle as shown in FIG. 4, if the external sensor is installed at an excessively low position, a sufficient angle for irradiating the floor cannot be obtained, so that the measurement system at a distant place is poor. In addition, there is a problem in that an irradiation angle required for measuring a stair surface cannot be obtained when descending the stairs.

[0048]

As described above, according to the present invention, in the legged mobile robot, the external sensor for detecting the object to be measured below is provided above the joint between the leg and the main body and the manipulator is provided. It is possible to detect and measure the object to be measured without receiving the interference of the manipulator since it is provided below the joint between the body and the main body.

Further, according to the present invention, since the external sensor is arranged at the waist or around the waist of the humanoid robot, the floor or obstacle in the forward direction, that is, the traveling direction is always irrespective of the movement of the neck joint or the torso. Objects can be easily and stably detected and measured.

Further, according to the present invention, the external sensor
Light emitting means for irradiating slit light and imaging means for imaging a light cutting line formed by the slit light on the object to be measured are provided, and a light cutting method or the like is performed based on an image taken by the imaging means. Since the distance to the object to be measured is calculated using the distance, the legged mobile robot knows the distance to the floor or the like and can detect the shape of the floor or the like. In addition, the landing position of the foot can be determined based on the calculated distance and shape, and the movement of the leg can be controlled.

Further, according to the present invention, the imaging means is constituted by at least two cameras, and associates the same object in each image captured by these cameras, Since the distance to the object is calculated using the parallax, the lower floor surface can be measured with high accuracy and the distant obstacle can be detected with high accuracy using binocular stereovision.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main configuration of a legged mobile robot according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the principle of the light-section method used in the embodiment.

FIG. 3 is a side view showing an external structure of the legged mobile robot according to the embodiment.

FIG. 4 is a side view showing an example where the installation position of the external sensor in the robot is inappropriate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser light source 2a Narrow base length camera 2b Wide base length camera 3 Light emission control part 4 Image capture part 5 Distance estimation part 6 Landing position determination part 7 Leg control part 8 Movement path determination part 20 Floor surface 20a Projection surface 21 Humanoid robot 22a Upper arm part 22b Lower arm part 23 Body part 24 Waist part 25 Leg part 27 External sensor 28 Multi-slit light irradiation range 31, 32, 33, 34 Joint rotation axis A Broken line showing movement of upper arm part 22a

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 7/28 G02B 7/11 B G03B 15/00 HF term (Reference) 2F065 AA01 AA06 AA67 DD11 FF01 FF02 FF04 FF09 GG04 HH05 HH06 JJ03 JJ05 JJ26 LL04 QQ03 QQ24 QQ31 2H051 BB11 BB25 CC02 3F059 AA00 BA02 BB06 BC10 CA04 CA06 DA03 DA05 DA08 DB02 DB10 DC08 DD12 FA05 FB12 FB17

Claims (7)

[Claims] An object comprising: a leg coupled to a main body for movement; and a manipulator coupled to the main body for moving an object in a space, wherein the manipulator is coupled to the main body. A leg-type mobile robot, wherein a portion is disposed above a joint between the leg and the main body, wherein the portion is below a joint between the manipulator and the main body and the leg is coupled to the main body. A legged mobile robot comprising an external sensor for detecting an object to be measured, above a part. 2. The leg according to claim 1, wherein the legged mobile robot is a humanoid robot having a waist, and the external sensor is disposed at the waist or around the waist. Mobile robot. 3. The external sensor according to claim 2, further comprising: a light emitting unit that emits slit light; and an image pickup unit that captures an optical cutting line formed by the slit light on the object to be measured. 3. The legged mobile robot according to 1 or 2. 4. The legged mobile robot according to claim 3, further comprising a distance calculation unit that calculates a distance to the object to be measured based on an image captured by the imaging unit. 5. The legged mobile robot according to claim 4, further comprising leg control means for controlling movement of the leg based on information on the distance calculated by the distance calculation means. 6. The legged mobile robot according to claim 3, wherein the surroundings are monitored using a light section method based on the image captured by the image capturing unit. 7. The image pickup means comprises at least two cameras, associates the same object in each image imaged by these cameras, and uses the parallax of the associated object to determine the object. The legged mobile robot according to any one of claims 3 to 6, wherein the distance to the mobile robot is calculated.