MOVING AMOUNT DETECTION DEVICE
20190302788 ยท 2019-10-03
Assignee
Inventors
Cpc classification
G06F3/0354
PHYSICS
G06F3/03544
PHYSICS
G05D1/0253
PHYSICS
G06F3/0317
PHYSICS
International classification
Abstract
The moving amount detection device includes: a plurality of optical sensors; a moving amount acquisition unit configured to acquire a moving amount of the moving body by using image data acquired from the optical sensors; and an arithmetic processing unit configured to detect the moving amount of the moving body in a coordinate system of a reference position on the moving body by performing arithmetic processing using the moving amount of the moving body in the predetermined coordinate systems of each of the plurality of optical sensors, wherein the plurality of optical sensors are disposed so that three or more of them are not arranged on the same straight line and the predetermined coordinate systems that are respectively set in the plurality of optical sensors have angles different from each other with respect to the coordinate system in the reference position.
Claims
1. A moving amount detection device, comprising: a plurality of at least three optical sensors having a light source for irradiating a floor surface where a moving body is located, the plurality of optical sensors acquiring image data of the floor surface; a moving amount acquisition unit configured to acquire a moving amount of the moving body in a one-axial or two-axial predetermined coordinate system by using the image data acquired from the optical sensors; and an arithmetic processing unit configured to detect the moving amount of the moving body in a coordinate system of a reference position on the moving body by performing arithmetic processing using the moving amount of the moving body in the predetermined coordinate systems in each of the plurality of optical sensors acquired by the moving amount acquisition unit, wherein the plurality of optical sensors are disposed so that three or more of them are not arranged on the same straight line in a top view of the moving body and the predetermined coordinate systems that are respectively set in the plurality of optical sensors have angles different from each other with respect to the coordinate system in the reference position, and the arithmetic processing unit detects the moving amount of the moving body in the coordinate system of the reference position by repeatedly performing arithmetic processing of converting the moving amount of the moving body in each of the plurality of optical sensors in the predetermined coordinate systems that are respectively set in the plurality of optical sensors into the moving amount of the moving body in the coordinate system of the reference position and integrating the converted moving amount.
2. The moving amount detection device according to claim 1, wherein the plurality of optical sensors are disposed on a circumference in which the coordinate center of the predetermined coordinate systems that are respectively set in the plurality of optical sensors are centered around the reference position, and the plurality of optical sensors are disposed so that angles formed by the predetermined coordinate systems respectively set in the plurality of optical sensors and the coordinate system in the reference position are shifted by an angle obtained by dividing 90? by the number of the plurality of optical sensors.
3. The moving amount detection device according to claim 1, further comprising a control unit configured to control so as to reduce a displacement amount between a current position of the moving body calculated by using a moving amount of the reference position in the arithmetic processing unit and a point closest to the current position on a planned moving path of the moving body, the planned moving path being planned in advance.
Description
BRIEF DESCRIPTION OF DRAWINGS
[0015]
[0016]
[0017]
[0018]
[0019]
[0020]
[0021]
[0022]
DESCRIPTION OF EMBODIMENTS
[0023] Hereinafter, although the present disclosure will be described with reference to embodiments of the disclosure, the present disclosure according to claims is not limited to the following embodiment. Further, not all the configurations described in this embodiment are necessary as the means for solving the problem.
[0024] First, a schematic configuration of a moving body 1 incorporating a moving amount detection device according to this embodiment is described with reference to
[0025] The optical sensors 2 include a light source that irradiates a floor surface where a moving body 1 is located, and acquires image data of the floor surface. The optical sensors 2 are, for example, optical mouse-type sensors. The light source of the optical sensors 2 is, for example, a laser light or an LED (Light Emitting Diode). Details of an arrangement of the plurality of optical sensors 2 in the moving body 1 will be described later.
[0026] The moving amount acquisition unit 3 uses image data acquired from the optical sensors 2 to acquire a moving amount of the moving body in a one-axial or two-axial predetermined coordinate system. The moving amount acquisition unit 3 includes an amplifier or the like that amplifies signals from the optical sensors 2.
[0027] The arithmetic processing unit 4 performs arithmetic processing by using moving amounts in the respective predetermined coordinate systems of the plurality of optical sensors 2, which are acquired by the moving amount acquisition unit 3, and thereby detects a moving amount of the moving body in the coordinate system of the reference position on the moving body.
[0028] The moving body 1 includes wheels 7, and a drive unit 8 including a motor connected to the wheels 7 and a battery for driving the motor is provided inside the housing 6. This motor in the drive unit 8 is driven so that the wheels 7 rotate to move the moving body 1. The moving body 1 may further include a control unit 5 that controls the drive unit 8 so as to reduce a displacement amount between a current position of the moving body 1 calculated by using a moving amount of the reference position in the arithmetic processing unit 4 and a point closest to the current position on a planned moving path of the moving body 1, the planned moving path being planned in advance. In this manner, the moving body 1 can autonomously move along the planned moving path.
[0029] The arithmetic processing unit 4 and the control unit 5 are arithmetic processing devices including a CPU (Central Processing Unit), a ROM (Read Only Memory), RAM (Random Access Memory), a communication interface, and the like. Further, the arithmetic processing unit 4 and the control unit 5 may include a HDD, an optical disk, or an optical magnetic disk, which are detachable, for storing various programs, control parameters, and the like, and supplying the programs and the data to a memory and the like as necessary. Note that the arithmetic processing unit 4 and the control unit 5 may be configured as one arithmetic unit.
[0030] Next, an arrangement of a plurality of optical sensors 2 in the moving body 1 will be described.
[0031] Further, the plurality of optical sensors 2 are disposed so that the predetermined coordinate systems that are respectively set in the plurality of optical sensors 2a, 2b and 2c have angles different from each other with respect to a coordinate system in a control center 10 which is the reference position. Note that a coordinate system of the control center 10 is defined as an x-y coordinate system, a predetermined coordinate system set in the optical sensor 2a is defined as an x1-y1 coordinate system, a predetermined coordinate system set in the optical sensor 2b is defined as an x2-y2 coordinate system, and a predetermined coordinate system set in the optical sensor 2c is defined as an x3-y3 coordinate system.
[0032] The x1-y1 coordinate system of the optical sensor 2a has an angle of ?1 with respect to the x-y coordinate system of the control center 10. The x2-y2 coordinate system of the optical sensor 2b has an angle of ?2 with respect to the x-y coordinate system of the control center 10. The x3-y3 coordinate system of the optical sensor 2c has an angle of ?3 with respect to the x-y coordinate system of the control center 10. The angles of ?1, ?2, and ?3 are angles different from each other.
[0033] The coordinate center of the x1-y1 coordinate system of the optical sensor 2a is located a distance R1 away from the control center 10. The coordinate center of the x2-y2 coordinate system of the optical sensor 2b is located a distance R2 away from the control center 10. The coordinate center of the x3-y3 coordinate system of the optical sensor 2c is located a distance R3 away from the control center 10. The further the coordinate center of the predetermined coordinate system of the optical sensor 2 is located from the control center 10, the higher the sensitivity of the optical sensor 2 becomes.
[0034] Next, a method for detecting a moving amount of the moving body in a coordinate system of the reference position will be described. Note that in the following descriptions, as appropriate, a configuration of the moving body 1 will be described with reference to
[0035] The arithmetic processing unit 4 repeatedly performs arithmetic processing of converting the moving amount of the moving body in each of the plurality of optical sensors 2 in the predetermined coordinate systems respectively set therein into the moving amount of the moving body in the coordinate system of the reference position and integrating the converted moving amount. In such a manner, the arithmetic processing unit 4 detects the moving amount of the moving body in the coordinate system of the reference position.
[0036] A moving amount ?P.sub.sen in the predetermined coordinate system of the optical sensors 2 is expressed as the Expression (1) by using a matrix M determined by a moving amount ?P.sub.odom of the control center and a geometric arrangement of the optical sensors 2.
?P.sub.sen=M?P.sub.odom(1)
[0037] As shown in
[Expression 1]
[0038]
[0039] ?P.sub.odom is expressed as the Expression (4) by using a pseudo inverse matrix M.sub.inv of the matrix M expressed by the Expression (3).
[Expression 2]
M.sub.inv=(M.sup.TM).sup.?1M.sup.T(3)
?P.sub.odom=M.sub.inv?P.sub.sen(4)
[0040] The moving amount ?P.sub.odom of the control center obtained from the Expression (4) is integrated as shown in the Expression (5), and thereby the current position of the moving body 1 can be calculated. Note that x.sub.odom, y.sub.odom, and ?.sub.odomn are the coordinates of the current positions which are currently calculated, and x.sub.odomo, y.sub.odomo, and ?.sub.odomo are the coordinates of the current positions which were calculated in the previous time.
[Expression 3]
[0041]
[0042]
[0043] Even in the case shown in
[0044] Note that a coordinate system of the control center 10 is defined as an x-y coordinate system, a predetermined coordinate system set in the optical sensor 2a is defined as an x1 coordinate system, a predetermined coordinate system set in the optical sensor 2b is defined as an x2 coordinate system, and a predetermined coordinate system set in the optical sensor 2c is defined as an x3 coordinate system. The x1 coordinate system of the optical sensor 2a has an angle of ?1 with respect to the x coordinate system of the control center 10. The x2 coordinate system of the optical sensor 2b has an angle of ?2 with respect to the x coordinate system of the control center 10. The x3 coordinate system of the optical sensor 2c has an angle of ?3 with respect to the x coordinate system of the control center 10. The angles of ?1, ?2, and ?3 are angles different from each other.
[0045] As shown in
[Expression 4]
[0046]
[0047] In the Expressions (3) to (5), when the matrix on the left side of the Expression (6) is defined as ?P.sub.sen, and the matrix of the second item on the right side is defined as ?P.sub.odom, the current position of the moving body 1 can be calculated in a manner similar to that in the case where the optical sensors are two-axial sensors.
[0048] Here, a problem regarding an arrangement position of the plurality of optical sensors 2 in comparative examples 1 to 3, and an effect of an arrangement position of the plurality of optical sensors 2 in the moving body 1 according to this embodiment which has been described with reference to
[0049]
[0050]
[0051]
[0052] In contrast to the comparative examples 1 to 3, as shown in
Modified Example 1
[0053]
[0054] As described above, the further the plurality of optical sensors 2a, 2b, and 2c are located from the control center 10 as the reference position, the higher the sensitivity thereof becomes. That is, sensitivity of the plurality of optical sensors 2a, 2b, and 2c depends on a distance of them from the control center 10 as the reference position. When the plurality of optical sensors 2 are disposed on the same circumference in which the coordinate centers of the predetermined coordinate systems respectively set in the optical sensors are centered around the control center 10 as the reference position, the sensitivity of each of the optical sensors can be uniform. Further, when the plurality of optical sensors 2 are disposed so that angles formed by the predetermined coordinate systems respectively set in the plurality of optical sensors and the x-y coordinate system in the control center 10 as the reference position are shifted by an angle obtained by dividing 90? by the number of the plurality of optical sensors, variations in sensitivity in a rotational movement can be suppressed.
Modified Example 2
[0055] Four or more optical sensors 2 may be disposed.
[0056] Further, the plurality of optical sensors 2 are disposed so that the predetermined coordinate systems that are respectively set in the plurality of optical sensors 2a, 2b, 2c and 2d have angles different from each other with respect to the coordinate system in the control center 10 which is the reference position. Note that a coordinate system of the control center 10 is defined as an x-y coordinate system, a predetermined coordinate system set in the optical sensor 2a is defined as an x1-y1 coordinate system, a predetermined coordinate system set in the optical sensor 2b is defined as an x2-y2 coordinate system, a predetermined coordinate system set in the optical sensor 2c is defined as an x3-y3 coordinate system, and a predetermined coordinate system set in the optical sensor 2d is defined as an x4-y4 coordinate system.
[0057] The x1-y1 coordinate system of the optical sensor 2a has an angle of ?1 with respect to the x-y coordinate system of the control center 10. The x2-y2 coordinate system of the optical sensor 2b has an angle of ?2 with respect to the x-y coordinate system of the control center 10. The x3-y3 coordinate system of the optical sensor 2c has an angle of ?3 with respect to the x-y coordinate system of the control center 10. The x4-y4 coordinate system of the optical sensor 2d has an angle of ?4 with respect to the x-y coordinate system of the control center 10. The angles of ?1, ?2, ?3, and ?4 are angles different from each other.
[0058] Even when four or more optical sensors 2 are disposed, variations in sensitivity among the plurality of optical sensors can be suppressed with respect to both translational and rotational movements by arranging the plurality of optical sensors 2 as described above.
[0059] Note that the present disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present disclosure. For example, even in the case where four or more optical sensors 2 are disposed, which is described with reference to the modified example 2, the optical sensors 2 can be disposed in the same manner as that in which the optical sensors 2 are disposed in the modified example 1. That is, the plurality of optical sensors are disposed on the same circumference in which the coordinate centers of the predetermined coordinate systems respectively set in the optical sensors are centered around the control center 10 as the reference position. Further, the plurality of optical sensors are disposed so that angles formed by the predetermined coordinate systems respectively set in the plurality of optical sensors and the x-y coordinate system in the control center as the reference position are shifted by an angle obtained by dividing 90? by the number of the plurality of optical sensors.
[0060] From the disclosure thus described, it will be obvious that the embodiments of the disclosure may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure, and all such modifications as would be obvious to one skilled in the art are intended for inclusion within the scope of the following claims.