Autonomous moving device and speaker / microphone combined unit for autonomous moving device

Abstract

This autonomous moving device comprises: a vehicle body; a first speaker that is attached to the vehicle body and that transmits sound waves to a region including an area in front of the vehicle body; and a first microphone and second microphone that are attached to the vehicle body, that receive sound waves reflected by an object, and that convert the sound waves into an electric signals. The first speaker and the first and second microphones are positioned outward of or at the outer periphery of the vehicle body in a view from the vertical direction. The first speaker is positioned between the first and second microphones in the left-right direction perpendicular to the frontward direction. The distance in the left-right direction from the first speaker or from the center of gravity of a plurality of speakers including the first speaker to each of the first and second microphones is equal.

Description

Autonomous mobile device and speaker / microphone combination unit for the autonomous mobile device

[0001] The present disclosure relates to an autonomous mobile device and a speaker-microphone combination unit for the autonomous mobile device.

[0002] Autonomous vehicles employing SLAM (Simultaneous Localization and Mapping) have been known for some time. For example, by combining external sensors such as cameras and laser sensors with internal sensors such as encoders and gyroscopes, the autonomous vehicle can estimate its own position and automatically generate a driving path, enabling it to automatically avoid obstacles without being bound to a fixed route. These autonomous vehicles do not require infrastructure such as embedded electrical wires in the floor or floor markings. SLAM using cameras is sometimes called Visual SLAM, and SLAM using laser sensors is sometimes called Light Detection and Ranging (LiDAR) SLAM.

[0003] Japanese Patent Application Laid-Open No. 2020-181485

[0004] SLAM requires expensive equipment such as cameras or LiDAR, making it expensive to manufacture, and it also requires creating maps every time a new location is installed or the layout of an existing location is changed, making it expensive to implement.

[0005] An object of the present disclosure is to provide an autonomous mobile device and a speaker / microphone combination unit for the autonomous mobile device that can be manufactured at low cost and at low installation costs.

[0006] One aspect of the present disclosure is an autonomous mobile device having a vehicle body, a first speaker attached to the vehicle body and configured to transmit sound waves toward an area including the front of the vehicle body, and a first microphone and a second microphone attached to the vehicle body and configured to receive sound waves reflected by an object and convert the sound waves into electrical signals. The first speaker and the first and second microphones are located on the outside or outer periphery of the vehicle body when viewed vertically. The first speaker is located between the first and second microphones in the left-right direction perpendicular to the front. The left-right distances from the center of gravity of the first speaker or a plurality of speakers including the first speaker to each of the first and second microphones are equal.

[0007] Another aspect of the present disclosure is a composite unit used in an autonomous mobile device, the composite unit including: a housing; a first speaker attached to the housing and configured to transmit sound waves toward an area including the front of the housing; and a first microphone and a second microphone attached to the housing and configured to receive sound waves reflected by an object and convert the sound waves into electrical signals. The first speaker and the first and second microphones are located outside or on the outer periphery of the housing when viewed vertically. The first speaker is located between the first and second microphones in the left-right direction perpendicular to the front. The left-right distances from the center of gravity of the first speaker or a plurality of speakers including the first speaker to each of the first and second microphones are equal.

[0008] According to one aspect and another aspect of the present disclosure, it is possible to provide an autonomous mobile device and a speaker-microphone combination unit for the autonomous mobile device, with low manufacturing costs and low installation costs.

[0009] FIG. 1 is a schematic diagram illustrating an overview of the operation of an autonomous mobile system including an autonomous mobile device according to multiple embodiments. FIG. 2 is an explanatory diagram illustrating a situation in which an autonomous mobile device travels along a planar roadway where multiple obstacles p1 to p4 exist, heading toward a destination P1. FIG. 3 is a block diagram illustrating an example of the configuration of an autonomous mobile device according to multiple embodiments. FIG. 4 is a block diagram illustrating an example of an echolocation configuration with one speaker and two microphones in an autonomous mobile device 100 according to the present embodiment. FIG. 5 is a block diagram illustrating details of each component in the echolocation configuration shown in FIG. 4. FIG. 6A is a plan view (part 1) illustrating an autonomous mobile device 100 having a speaker and microphone layout that increases the difference in sound pressure between sound waves received by a left-right pair of first and second microphones 51L and 51R. FIG. 6B is a plan view (part 2) illustrating an autonomous mobile device 100 having a speaker and microphone layout that increases the difference in sound pressure between sound waves received by a left-right pair of first and second microphones 51L and 51R. Fig. 6C is a plan view (part 3) of an autonomous mobile device 100 having a speaker and microphone layout that increases the difference in sound pressure between sound waves received by the left-right pair of first and second microphones 51L and 51R. Fig. 7A is a plan view (part 4) of an autonomous mobile device 100 having a speaker and microphone layout that increases the difference in sound pressure between sound waves received by the left-right pair of first and second microphones 51L and 51R. Fig. 7B is a plan view (part 5) of an autonomous mobile device 100 having a speaker and microphone layout that increases the difference in sound pressure between sound waves received by the left-right pair of first and second microphones 51L and 51R. Fig. 7C is a plan view (part 6) of an autonomous mobile device 100 having a speaker and microphone layout that increases the difference in sound pressure between sound waves received by the left-right pair of microphones 51L and 51R. Fig. 7D is a plan view (part 7) showing the autonomous mobile device 100 having a speaker and microphone layout that increases the difference in sound pressure between sound waves received by the pair of left and right microphones 51L, 51R. Fig. 7E is a side view (part 1) showing the layout of the autonomous mobile device 100 that increases the sound pressure of sound waves received by the first and second microphones 51L, 51R from the front or diagonally forward. Fig. 7F is a side view (part 2) showing the layout of the autonomous mobile device 100 that increases the sound pressure of sound waves received by the first and second microphones 51L, 51R from the front or diagonally forward.FIG. 7G is a side view (part 1) showing the layout of a combined unit 300 that increases the sound pressure of sound waves received by the first and second microphones 51L, 51R from the front or diagonally forward. FIG. 7H is a side view (part 2) showing the layout of a combined unit 300 that increases the sound pressure of sound waves received by the first and second microphones 51L, 51R from the front or diagonally forward. FIG. 8 is a plan view showing an autonomous mobile device equipped with a combined unit 300 for an autonomous mobile device having a speaker and microphone layout that increases the difference in sound pressure of sound waves received by the pair of left and right microphones 51L, 51R. FIG. 9 is a plan view showing the structure of a housing 210 that reduces the sound pressure of sound waves (noise) arriving from behind. FIG. 10A is a plan view (part 1) showing a modified embodiment that reduces the sound pressure of sound waves (noise) arriving from behind. FIG. 10B is a plan view (part 2) showing a modified embodiment that reduces the sound pressure of sound waves (noise) arriving from behind. FIG. 10C is a plan view (part 3) showing a modified embodiment in which the sound pressure of sound waves (noise) arriving from behind is reduced. FIG. 10D is a plan view (part 4) showing a modified embodiment in which the sound pressure of sound waves (noise) arriving from behind is reduced. FIG. 11 is a plan view (part 5) showing a modified embodiment in which the sound pressure of sound waves (noise) arriving from behind is reduced. FIG. 12 is a plan view (part 6) showing a modified embodiment in which the sound pressure of sound waves (noise) arriving from behind is reduced. FIG. 13 is a plan view showing an example of the structure of a composite unit that increases the sound pressure of sound waves arriving from diagonally forward among the sound waves received by the first and second microphones 51L and 51R. FIG. 14A is a plan view (part 1) showing a modified embodiment in which the sound pressure of sound waves arriving from diagonally forward among the sound waves received by the first and second microphones 51L and 51R is increased. Fig. 14B is a plan view (part 2) showing a modified embodiment in which the sound pressure of sound waves arriving from diagonally forward among the sound waves received by the first and second microphones 51L and 51R is increased. Fig. 15A is a plan view (part 3) showing a modified embodiment in which the sound pressure of sound waves arriving from diagonally forward among the sound waves received by the first and second microphones 51L and 51R is increased. Fig. 15B is a plan view (part 4) showing a modified embodiment in which the sound pressure of sound waves arriving from diagonally forward among the sound waves received by the first and second microphones 51L and 51R is increased.Fig. 16 is a plan view (part 5) showing a modified embodiment in which the sound pressure of sound waves arriving from diagonally forward among the sound waves received by the first and second microphones 51L and 51R is increased. Fig. 17A is a plan view (part 6) showing a modified embodiment in which the sound pressure of sound waves arriving from diagonally forward among the sound waves received by the first and second microphones 51L and 51R is increased. Fig. 17B is a plan view (part 7) showing a modified embodiment in which the sound pressure of sound waves arriving from diagonally forward among the sound waves received by the first and second microphones 51L and 51R is increased. Fig. 18A is a plan view showing an example of the structure of a composite unit 300 that reduces the sound pressure of sound waves arriving from opposite left and right sides among the sound waves received by the first and second microphones 51L and 51R. Fig. 18B is a plan view (part 1) showing another example of the structure of the combined unit 300 that reduces the sound pressure of sound waves arriving from opposite sides among the sound waves received by the first and second microphones 51L and 51R. Fig. 18C is a plan view (part 2) showing another example of the structure of the combined unit 300 that reduces the sound pressure of sound waves arriving from opposite sides among the sound waves received by the first and second microphones 51L and 51R. Fig. 19 is a side view showing an example of the structure of the combined unit 300 that reduces the sound pressure of sound waves reflected by unevenness 63 in the ground 62 among the sound waves received by the first and second microphones 51L and 51R. Fig. 20 is a plan view showing an example of the structure of the combined unit 300 that increases the sound pressure of sound waves arriving from the side of the combined unit 300 to prevent entanglement of an object 60A on the side. Fig. 21 is a plan view showing an example of the structure of a combined unit 300 that increases the sound pressure of sound waves arriving from the front of the autonomous mobile device 100 to prevent collision with an object 60A in front. Fig. 22A is a plan view showing an example of the structure of a combined unit 300 that increases the sound pressure of sound waves arriving from the pair of left and right microphones 51L, 51R from diagonally forward, while also increasing the sound pressure of sound waves arriving from at least one of the front and the side. Fig. 22B is a plan view showing another example of the structure of a combined unit 300 that increases the sound pressure of sound waves arriving from the pair of left and right microphones 51L, 51R from diagonally forward, while also increasing the sound pressure of sound waves arriving from at least one of the front and the side. Fig. 23A is a plan view (part 1) showing another modified example of the number and arrangement of microphones and speakers provided in the autonomous mobile device 100.Fig. 23B is a plan view showing another modified example of the number and arrangement of microphones and speakers provided in the autonomous mobile device 100 (part 2). Fig. 23C is a plan view showing another modified example of the number and arrangement of microphones and speakers provided in the autonomous mobile device 100 (part 3). Fig. 23D is a plan view showing another modified example of the number and arrangement of microphones and speakers provided in the autonomous mobile device 100 (part 4). Fig. 23E is a plan view showing another modified example of the number and arrangement of microphones and speakers provided in the autonomous mobile device 100 (part 5).

[0010] Hereinafter, autonomous mobile devices, autonomous mobile systems, and speaker-microphone combination units for autonomous mobile devices according to multiple embodiments will be described in detail with reference to the drawings. Note that the embodiments described below are comprehensive or specific examples. The numerical values, shapes, materials, components, component installation positions, and connection forms shown in the following embodiments are merely examples and are not intended to limit the scope of the present disclosure. Furthermore, among the components in the following embodiments, components that are not recited in the independent claims that represent the highest concepts will be described as optional components. Furthermore, the dimensional proportions in the drawings are exaggerated for the sake of explanation and may differ from the actual proportions.

[0011] Furthermore, the following embodiments and their modifications may include similar components, and the similar components will be given common reference numerals and redundant explanations will be omitted.

[0012] (Overview of Autonomous Mobile Device) The autonomous mobile device according to multiple embodiments has a configuration that can autonomously reach a target object, and can be used, for example, in the interior space of buildings such as houses and offices, or in structures such as factories, or in external spaces in some cases. Furthermore, by using a propeller or the like that can move through the air in the mobility mechanism, it is also possible to configure an air vehicle such as a drone to autonomously reach a target object. Furthermore, the autonomous mobile device can be applied to vehicles such as passenger cars and buses, as well as to mobile objects such as airplanes, spacecraft, ships, and submarines.

[0013] The autonomous mobile device reaches the target object while avoiding obstacles using information output by the target object without using an imaging device such as a camera, LiDAR, or radar. The information output by the target object is not particularly limited, but examples include radio waves or high-frequency electromagnetic waves. Hereinafter, the explanation will be continued using radio waves as an example. The autonomous mobile device receives radio waves from a beacon or the like using multiple antennas, uses technology to estimate the direction of arrival of the radio waves, estimates the direction of the target object emitting the radio waves, and moves in the estimated direction. If an obstacle exists outside the line of sight between the target object and the autonomous mobile device, the autonomous mobile device may move in the direction of arrival of the radio waves reflected by the obstacle. However, during movement, the autonomous mobile device may receive radio waves directly from the target object. In this case, the autonomous mobile device can change its movement direction toward the target object while moving toward the obstacle. As a result, it is possible to move toward the target object while avoiding the obstacle. Furthermore, if there is an obstacle in the line of sight between the target object and the autonomous mobile device, the reception strength of the radio waves will fluctuate as the autonomous mobile device moves toward the obstacle, allowing the autonomous mobile device to detect the presence of the obstacle. In this way, the autonomous mobile device can reach the target object while avoiding obstacles by continuing to move in the direction of the strongest radio wave reception strength while estimating the direction from which the radio waves are coming.

[0014] As described above, an autonomous mobile device does not need to be equipped with an imaging device such as a CCD camera, LiDAR, or radar for route search, as used in conventional technology. In other words, the autonomous mobile device of the present disclosure is equipped with multiple antennas, a control unit, and a drive unit that measure the intensity of the information and move in the direction of the information, thereby enabling it to reach a target object from which information is output. Furthermore, sound waves emitted from a speaker mounted on the autonomous mobile device are reflected by objects around the autonomous mobile device and received by multiple microphones, and the direction of travel of the autonomous mobile device can be set based on the sound waves. This allows the autonomous mobile device to set its direction of travel while avoiding narrow or complex routes. As a result, it is possible to reach a target object while selecting an optimal route that is less affected by objects (including obstacles) around the autonomous mobile device.

[0015] Next, with reference to FIGS. 1 and 2, an overview will be given of the operation principles of an autonomous mobile device 100 according to a plurality of embodiments and an autonomous mobile system 1000 including the autonomous mobile device 100. FIG.

[0016] (Overview of Digital Pheromones) First, with reference to FIG. 1 , a mechanism (digital pheromones) will be described in which an autonomous mobile device 100 estimates the direction of arrival of radio waves from a beacon or the like and continues moving in the direction of the strongest radio wave reception, thereby reaching a target object (transmitter device 200) while avoiding obstacles J1 and J2. The autonomous mobile device 100 receives radio waves transmitted from a transmitter device 200 (corresponding to the target object) located at a target location. Because the line of sight between the autonomous mobile device 100 and the transmitter device 200 is blocked by obstacle J2, the autonomous mobile device 100 receives the radio waves via route K3 → route K2 → route K1. Note that the autonomous mobile device 100 may also receive radio waves from the line of sight direction depending on the size of obstacle J2 and the beacon frequency. However, it is assumed that the radio waves received via route K1 have the strongest intensity. The autonomous mobile device 100 estimates the direction of arrival of the strongest radio wave using multiple antennas mounted on the autonomous mobile device 100 and moves based on the estimated direction of arrival.

[0017] As the autonomous mobile device 100 moves along route K1 toward obstacle J1, the received radio wave strength increases as the autonomous mobile device 100 approaches obstacle J1, and so the autonomous mobile device 100 continues to move along route K1 toward obstacle J1. However, upon reaching position x1, the transmitting device 200 appears in the autonomous mobile device 100's line of sight, enabling the autonomous mobile device 100 to directly receive radio wave TS3. Therefore, at position x1, the received radio wave TS3 strength is greater than that of radio wave TS2, so the autonomous mobile device 100 attempts to change its direction of movement to the direction from which radio wave TS3 is arriving. While the autonomous mobile device 100 could also move along the line from which radio wave TS3 is arriving, doing so could result in the autonomous mobile device 100 colliding with obstacle J2. Therefore, the autonomous mobile device 100 recognizes the presence of obstacle J2 based on the fact that it was unable to receive radio wave TS3 along route K1 up to position x1, the strong radio wave TS3 it received at position x1, and the estimated direction of arrival. Based on this, the autonomous mobile device 100 recognizes the presence of obstacle J2 and moves along route K2. The autonomous mobile device 100, moving in the direction of route K2, recognizes the presence of obstacle J1 based on the fact that the arrival directions of the radio waves output from the transmitting device 200 are gradually widening and that it changed its direction of movement at position x1, and is therefore able to estimate route K3. Therefore, the autonomous mobile device 100 changes its direction of travel toward the transmitting device 200 at position x2, and is able to reach the transmitting device 200.

[0018] (Outline of Echolocation) Next, a mechanism (echolocation) by which the autonomous mobile device 100 reaches a target object P1 while selecting a suitable travel path that is less affected by obstacles p1 to p4 will be described with reference to Fig. 2. Fig. 2 is an explanatory diagram showing a situation in which the autonomous mobile device 100 travels on a planar travel path where multiple obstacles p1 to p4 exist, heading toward a destination P1.

[0019] When the autonomous mobile device 100 autonomously travels from position P0 to destination P1, an obstacle p2 exists on the travel path x0, which is the shortest route. In this case, the autonomous mobile device 100 outputs sound waves in the direction of travel and receives the sound waves reflected off the surface of obstacle p2. The autonomous mobile device 100 detects obstacle p2 from the received sound waves and changes its direction of travel at position P2 in front of obstacle p2 to avoid collision with obstacle p2.

[0020] In this case, it is desirable for the autonomous mobile device 100 to change its direction of movement to the left to avoid the obstacle p2. That is, the travel path x1 to the left of the obstacle p2 as seen from the autonomous mobile device 100 is an open space, so the autonomous mobile device 100 can travel without being restricted by the obstacle. However, the travel path x2 to the right of the obstacle p2 is complex and intricate, so the autonomous mobile device 100 is subject to many restrictions due to the obstacles when traveling. Therefore, it is desirable to change the direction of movement of the autonomous mobile device 100 to the left.

[0021] On the other hand, the travel path x2 to the right of the obstacle p2 is complicated and intricate, and the autonomous mobile device 100 is subject to many restrictions when traveling due to the obstacles. More specifically, a) if there is an obstacle in close proximity to the antenna, a phase shift occurs, significantly reducing the accuracy of direction detection. Also, b) if the autonomous mobile device 100 enters a complex space with many obstacles like this, there is a problem that the radio wave reflection becomes complex and the autonomous mobile device 100 becomes unable to escape.

[0022] The autonomous mobile device 100 receives sound reflected by surrounding objects (obstacles p1 to p4) using a pair of left and right microphones. By comparing the left and right sound signals, the autonomous mobile device 100 can avoid the complex space filled with obstacles p1 to p4 and travel through an open space without being restricted by surrounding objects to reach the destination P1. A more specific method will be described later.

[0023] (Details of Autonomous Mobile Device) The detailed configuration of the autonomous mobile device 100 according to multiple embodiments will be described with reference to FIG. 3 . The autonomous mobile device 100 includes a receiving unit 110 such as a plurality of antennas, a switch unit 120 that selects the receiving elements of the receiving unit 110, a control unit 130, a memory unit 140, an information acquisition unit 150, a drive unit 160, and a movement unit 170. Note that a display unit 180 may also be included in the autonomous mobile device 100. Furthermore, the autonomous mobile device 100 basically moves by driving a movement unit 170 such as wheels, belts, caterpillars, or propellers based on drive information output from the drive unit 160 shown in FIG. 3 . Note that the receiving unit 110 is equipped with a plurality of receiving elements.

[0024] The receiving unit 110 is an antenna that receives radio waves (including high-frequency electromagnetic waves) output from the transmitting device 200. For example, the receiving unit 110 may be an array antenna composed of multiple antenna elements. When the receiving unit 110 is an array antenna, the antenna elements constituting the array antenna may be arranged in any desired arrangement. For example, the antenna elements may be arranged in a line in the direction of travel of the autonomous mobile device 100 or in a direction intersecting the direction of travel, such as a direction perpendicular to the direction of travel. Furthermore, the antenna elements may be arranged to form a rectangular or annular shape on a plane that does not intersect the direction of travel of the autonomous mobile device 100 or a plane that intersects the direction of travel of the autonomous mobile device 100. Furthermore, the antenna elements may be arranged in a curved shape. Furthermore, the array antenna does not need to be a single antenna; multiple array antennas may be arranged to improve the accuracy of estimating the direction of arrival of radio waves, etc. The receiving unit 110 may also be composed of multiple antennas with directivities in different directions. In this case, the multiple antennas may be arranged in the same manner as the antenna elements of an array antenna. Furthermore, a partition plate made of metal or the like may be provided on at least one omnidirectional antenna, so that the intensity of radio waves or high-frequency electromagnetic waves in the direction surrounded by the partition plate can be detected.

[0025] The switch unit 120 is configured to select one of the receiving elements of the receiving unit 110 and output information such as radio waves received by the receiving element. Therefore, the number of switches in the switch unit 120 is the same as the number of receiving elements provided in the receiving unit 110, with one switch corresponding to one receiving element. For example, if the receiving unit 110 is an array antenna, the switch unit 120 selects multiple antenna elements and outputs information such as the strength and phase of the radio waves received by the multiple antenna elements to the phase difference determination unit 131 and the reception intensity determination unit 132, which will be described later. Furthermore, the switch unit 120 is preferably a semiconductor switch, but is not limited to this, and any switch capable of opening and closing an electrical connection of any configuration can be used.

[0026] The control unit 130 can be realized using a microcomputer equipped with a CPU (Central Processing Unit) etc. A computer program (autonomous movement program) for causing the microcomputer to function as the control unit 130 is installed in the microcomputer and executed. As a result, the microcomputer functions as multiple information processing units equipped in the control unit 130.

[0027] The control unit 130 includes a phase difference determination unit 131, a reception strength determination unit 132, a receiving element selection unit 133, an angle estimation unit 134, an operation control unit 135, and a contact determination unit 136 as a plurality of information processing units.

[0028] The phase difference determination unit 131 analyzes received signals from the multiple receiving elements of the receiving unit 110 selected by the receiving element selection unit 133, and determines the phase difference between the received signals from the difference in arrival time between the received signals. The determined phase difference is output to the angle estimation unit 134. Furthermore, when the autonomous mobile device 100 is stopped or moving, the phase difference determination unit 131 can also determine one angle from multiple phase differences between multiple received signals.

[0029] The reception strength determination unit 132 determines the reception strength from the multiple receiving elements of the receiving unit 110 selected by the receiving element selection unit 133. The estimated reception strength is output to the operation control unit 135. The estimated reception strength may also be output to the receiving element selection unit 133. Note that the reception strength can be indicated in any unit related to reception strength and may be indicated as relative information. The reception strength can be output to the operation control unit 135 and the receiving element selection unit 133 as reception strength information in any format.

[0030] The receiving element selection unit 133 selects an element for receiving radio waves, etc. from the multiple receiving elements provided in the receiving unit 110. It is preferable that one or more receiving elements are selected. In order for the phase difference determination unit 131 to determine the phase difference, the receiving element selection unit 133 selects multiple receiving elements. It is also possible to select the receiving elements in order, select one or more receiving elements determined to have strong reception strength by the reception strength determination unit 132, and estimate the arrival direction of the radio waves, etc. in the angle estimation unit 134 via the phase difference determination unit 131.

[0031] The angle estimation unit 134 can employ any direction-of-arrival estimation method, such as a method in which several pairs of two antenna elements are used, a complex reception response to an incoming wave is calculated in advance from the phase difference between the antenna elements, an evaluation function is introduced, and the angle at which the evaluation function value is maximized is determined as the direction of arrival of the radio wave. The angle estimation unit 134 can also estimate the direction of arrival of the radio wave from the phase differences between multiple antenna elements. For example, the MUSIC (Multiple Signal Classification) method or the Root-MUSIC method using the eigenvalues ​​and eigenvectors of a correlation matrix can be employed. Furthermore, the ESPRIT (Estimation of Signal Parameters via Rotational Invariance Techniques) method can also be employed. The angle estimated in this manner is stored in the angle information storage unit 141 of the storage unit 140 as angle information from an arbitrary reference axis. The estimated angle information may also be associated with the reception strength determined by the reception strength determination unit 132 and stored in the angle information storage unit 141. Furthermore, the estimated angle information may be associated with the determined reception strength and time information and stored in the angle information storage unit 141. The time information can be received by the receiving unit 110 from outside the autonomous mobile device 100, or the autonomous mobile device 100 can measure the time using a timing unit (not shown).

[0032] Furthermore, there may be multiple angles estimated by the angle estimation unit 134. When there are multiple angles to be estimated, the reception strength at each angle is received from the reception strength determination unit 132, and the angle estimation unit 134 may associate each angle with the reception strength and store them in the angle information storage unit 141. For example, if there is an obstacle, radio waves reflected by the obstacle and radio waves propagating along the line of sight may be received by the autonomous mobile device 100 at different angles. Furthermore, radio waves reflected by an obstacle may be further reflected by another obstacle and received by the autonomous mobile device 100 at yet another different angle. In this way, reflected waves from an obstacle may be reflected multiple times and reach the autonomous mobile device 100. Basically, the autonomous mobile device 100 moves in the direction of higher reception strength, but there is a possibility that an obstacle may prevent the autonomous mobile device 100 from moving in the direction of higher reception strength, or that the autonomous mobile device 100 may take an incorrect route. In this way, there may be cases where the autonomous mobile device 100 is forced to move in the direction of another reflected wave, so when multiple angles are estimated, the autonomous mobile device 100 can associate this information with the reception strength and store this information in the angle information storage unit 141.

[0033] The operation control unit 135 generates movement direction information including a movement direction for moving the autonomous mobile device 100, corresponding to the magnitude or change in the reception strength determined by the reception strength determination unit 132 and the arrival direction of the radio waves estimated by the angle estimation unit 134. In the embodiment, when the operation control unit 135 determines that there is an obstacle or a complex space around the autonomous mobile device 100 based on, for example, information from the information acquisition unit 150 described below, the operation control unit 135 generates movement direction information by determining that the reliability of both or one of the estimation result by the angle estimation unit 134 and the determination result by the reception strength determination unit 132 is lower than a predetermined reference value. In other words, basically, when the reliability index (I) is lower than a predetermined reference value, the operation control unit 135 controls movement so as to avoid the surrounding area.

[0034] For example, the operation control unit 135 may generate movement direction information by weighting the estimated arrival direction of radio waves according to their reliability. More specifically, the operation control unit 135 may multiply the reception strength (R) of multiple estimated arrival directions of radio waves by the degree of reliability (reliability: I) and control the movement toward the arrival direction with the larger product (R x I). Not only when multiple arrival directions of radio waves can be estimated simultaneously, but also when multiple arrival directions of radio waves are compared in past history. That is, the operation control unit 135 may generate movement direction information by weighting the arrival direction of radio waves stored in the storage unit 140 with an index according to their reliability. Furthermore, when reliability decreases, the operation control unit 135 may control the movement toward a space or direction with higher reliability.

[0035] There are various methods by which the operation control unit 135 can determine that reliability is low due to the presence of an obstacle or a complex space around the autonomous mobile device 100. For example, the operation control unit 135 may determine reliability based on at least one of the magnitude, change, number of receptions, left-right comparison, comparison with past history, distance to the estimated obstacle, shape of the space, reception strength, amount of noise, and stability of the arrival direction angle of the received output information. For example, if the reception strength determined by the reception strength determination unit 132 in the estimated direction oscillates periodically, it may be determined that an obstacle exists in the estimated direction and the reliability may be lowered. This is because if the reception strength oscillates periodically, there may be an obstacle around the autonomous mobile device 100 or between the autonomous mobile device 100 and the target object, and diffracted waves may be received.

[0036] In addition, the autonomous mobile device 100 may include an obstacle measurement unit that measures the distance to an obstacle so that the operation control unit 135 can determine whether there are any obstacles or complicated spaces in the vicinity. In this embodiment, the information acquisition unit 150 to the contact determination unit 136, which will be described later, function as the obstacle measurement unit. The information acquisition unit 150 may be an infrared sensor, an ultrasonic sensor, or a depth sensor. Furthermore, when the operation control unit 135 receives contact prediction information or contact information from the contact determination unit 136, it may determine that the reliability is low and change the movement direction to avoid the obstacle or the complicated space. In this case, the changed direction may be maintained temporarily or for a predetermined period of time.

[0037] In this way, the operation control unit 135 can associate an index according to reliability, the direction of arrival and reception strength of radio waves, and the history of control content of the autonomous mobile device 100, and store them in the storage unit 140, and generate movement direction information taking into account changes in the history over time. The operation control unit 135 can associate a movement direction, a movement time or movement distance in that movement direction, and reliability, etc., and store them in the movement direction information storage unit 142. As described above, the operation control unit 135 can calculate past movement history and generate map information from the information stored in the movement direction information storage unit 142, making it possible to move around obstacles with low reliability or in complex spaces.

[0038] Furthermore, the operation control unit 135 may move while maintaining the current moving direction when the radio wave intensity is very weak or when the angle estimation unit 134 cannot estimate the direction of arrival of the radio waves. For example, if a null point occurs due to interference between emitted radio waves and reflected radio waves, the autonomous mobile device 100 may be able to re-estimate the direction of arrival of the radio waves by moving to another point.

[0039] Furthermore, the operation control unit 135 can perform machine learning or deep learning using information such as movement history information, angle information, estimated radio wave direction information, and reliability, and store machine learning result information or deep learning result information in the storage unit 140. Therefore, the operation control unit 135 stores reliability history according to reliability, movement direction information, and the like as teacher data in the storage unit 140. Furthermore, the machine learning result information or deep learning result information can be stored in the storage unit 140 in association with information such as movement direction information, angle information, estimated radio wave direction information, and reliability.

[0040] The contact determination unit 136 determines whether or not there is a possibility that the autonomous mobile device 100 will come into contact with an obstacle, based on the acquired information acquired by the information acquisition unit 150. When the information acquisition unit 150 detects an obstacle, it transmits information about the detected obstacle to the contact determination unit 136. When it is predicted that the autonomous mobile device 100 will come into contact with an obstacle based on the movement direction and size of the autonomous mobile device 100 and the acquired information about the obstacle, the contact determination unit 136 transmits contact prediction information to the operation control unit 135. Furthermore, when it is determined that the autonomous mobile device 100 is in contact with an obstacle, the contact determination unit 136 transmits contact information to the operation control unit 135.

[0041] The storage unit 140 is a computer-readable storage medium. For example, the storage unit 140 may be a read-only memory (ROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a random access memory (RAM), a hard disk, or the like.

[0042] The storage unit 140 includes an angle information storage unit 141 , a movement direction information storage unit 142 , and a reception intensity information storage unit 143 .

[0043] The angle information storage unit 141 stores angle information of radio waves whose arrival direction is estimated by the angle estimation unit 134. The angle information may be information from a predetermined reference axis, and the reference axis may be based on the physical contour of the autonomous mobile device 100. For example, the contour may be represented by two-dimensional relative coordinates separate from the space in which the autonomous mobile device 100 is moving, and a line represented by the relative coordinates may be used as the reference axis. The angle information may be stored in association with estimated radio wave reception strength information and time information when the angle information was estimated. This is because, in the above-mentioned specific cases, angle information other than angle information with the strongest reception strength may be used, and there may be cases where it is necessary to compare the angle information with past angle information. Furthermore, the angle information may represent an angle changed from the initially determined angle, making it easier to create map information.

[0044] The movement direction information storage unit 142 can store movement direction information determined by the operation control unit 135 and actually traveled by the autonomous mobile device 100, in association with time information indicating when the autonomous mobile device 100 started moving in the movement direction and time information indicating when the autonomous mobile device 100 ended moving in the movement direction. Furthermore, the time information indicating when the autonomous mobile device 100 started moving in the movement direction or the time information indicating when the autonomous mobile device 100 ended moving in the movement direction, and time information indicating the duration of the movement in the movement direction, can be stored in association with the movement direction information in the movement direction information storage unit 142. The operation control unit 135 can also reproduce past movement paths of the autonomous mobile device 100 based on this information. The operation control unit 135 can also select a route to reach a target object without retracing the same movement path by referring to past movement paths. The contact determination unit 136 can also estimate the position of an obstacle by referring to past movement paths. The control unit 130 can also perform machine learning or deep learning, and the machine learning result information or deep learning result information can be stored in the storage unit 140, including the movement direction information storage unit 142. In addition, the machine learning result information and deep learning result information may be stored in association with information such as movement direction information, angle information, radio wave estimated direction information, and reliability.

[0045] The reception strength information storage unit 143 stores reception strength information of radio waves received by the multiple receiving elements determined by the reception strength determination unit 132. Furthermore, the reception strength of radio waves in the radio wave arrival direction estimated by the multiple receiving elements is stored in the reception strength information storage unit 143. Furthermore, the reception strength information can be stored in the reception strength information storage unit 143 in association with time information when the reception strength was determined.

[0046] The drive unit 160 includes a mechanism for driving the movement unit 170 in order to move the autonomous mobile device 100 in the movement direction determined by the operation control unit 135. For example, if the movement unit 170 is a wheel, the drive unit 160 includes a mechanism for rotating the wheel; if the movement unit 170 is a caterpillar, the drive unit 160 includes a mechanism for rotating the caterpillar; and if the movement unit 170 is a propeller, the drive unit 160 includes a mechanism for rotating the propeller. Note that the drive unit 160 is not limited to the above-described aspects, and can include any drive configuration for driving the configuration of the movement unit 170.

[0047] The moving unit 170 is a part that constitutes the means for moving the autonomous mobile device 100. If the autonomous mobile device 100 is a vehicle, the moving unit 170 may be wheels including tires, or caterpillars, etc. Furthermore, if the autonomous mobile device 100 is a flying object such as a drone or helicopter, the moving unit 170 may be a propeller. Note that the moving unit 170 is not limited to the above-mentioned aspects, and may include any moving mechanism that can move the autonomous mobile device 100.

[0048] The display unit 180 is optional and can be attached to the autonomous mobile device 100 or installed in a monitor space separate from the autonomous mobile device 100, making it possible to check image information of the direction of movement of the autonomous mobile device 100. In this way, by checking the image information output to the display unit 180, it is also possible to check whether the autonomous mobile device 100 is moving normally.

[0049] The transmitting device 200 in FIG. 1 can be placed around or attached to a target object. The transmitting device 200 may also be the target object. The information output by the transmitting device 200 must be receivable by the receiving unit 110 of the autonomous mobile device 100. Examples of information output by the transmitting device 200 include, but are not limited to, radio waves and high-frequency electromagnetic waves, as described above. The information can also be electromagnetic waves, vibration waves, and the like of any frequency. The frequencies of radio waves, vibration waves, and the like do not need to be fixed and can be changed periodically or randomly. The transmitting device 200 can also be configured to repeatedly sweep frequencies within a predetermined frequency range. Frequency fluctuations may make it easier for the autonomous mobile device 100 to determine the presence of an obstacle without the information acquisition unit 150. The transmitting device 200 may also be a user-used electronic device, such as a mobile phone, PHS phone, smartphone, or personal digital assistant (PDAs), or another autonomous mobile device.

[0050] The autonomous mobile device 100 according to the embodiment may further include a transmitter (not shown) that transmits information about arrival at a target object or information about an abnormality during movement to an external device wirelessly or via a wired connection. The transmitter can transmit the arrival information and the abnormality information to an external electronic device wirelessly via so-called mobile communication. Alternatively, wireless communication based on at least one short-range wireless communication standard, such as wireless LAN or Bluetooth (registered trademark), may be performed. Alternatively, the transmitter may communicate with an external device via a cable (e.g., a USB cable or an optical cable). This configuration allows another device to perform the next process in response to receiving the arrival information or the abnormality information.

[0051] The transmission destination of the transmission unit may be, for example, a computer located on the cloud, a mobile phone carried by the user, a PHS phone, a smartphone, a personal digital assistant, or other electronic device used by the user.

[0052] (Details of Echolocation) The information acquisition unit 150 may be a device equipped with one or more speakers and two or more microphones. As an example, a device equipped with one speaker and two microphones will be described with reference to FIG. 4. FIG. 4 is a block diagram showing an example of an echolocation configuration with one speaker and two microphones in the autonomous mobile device 100 according to this embodiment. FIG. 5 is a block diagram showing details of each component in the echolocation configuration shown in FIG. 4.

[0053] As shown in FIG. 4, the autonomous mobile device 100 includes a control unit 130, a memory unit 140, a drive unit 160, four wheels as a moving unit 170, and also includes one voice transmitting unit 150C and two voice receiving units 150L and 150R as one form of an information acquisition unit 150.

[0054] The sound transmitting unit 150C is attached to the body 190 of the autonomous mobile device 100, and transmits sound waves toward an area including the front of the body 190 (positive direction of the X-axis). As shown in FIG. 5 , the sound transmitting unit 150C includes a speaker 41, an amplifier 42, and a D / A conversion unit 43. Note that although an example including one sound transmitting unit 150C is described in FIGS. 4 and 5 , multiple sound transmitting units 150C may be provided, as described below. For example, if the sound emitted from the sound transmitting unit 150C does not reach the entire periphery of the autonomous mobile device 100, it is also possible to provide two sound transmitting units 150C, for example, on the left and right sides of the autonomous mobile device 100.

[0055] The sound transmitting unit 150C outputs ultrasonic waves or sound waves with frequencies in the human audible range. Note that the sound transmitting unit 150C can also be configured to output sound waves other than ultrasonic waves and frequencies in the audible range. "Sound waves" refers to a general term for elastic waves that propagate through gas, liquid, or solid.

[0056] The audio transmitting unit 150C outputs sound waves at a predetermined period or irregularly. The audio transmitting unit 150C also has a function of changing the frequency of the sound waves to be transmitted. That is, when the frequency of the sound waves generated by the audio signal generating unit 26 (described later) is changed, the audio transmitting unit 150C transmits sound waves of the changed frequency. When multiple audio transmitting units 150C are provided, the timing at which the audio transmitting units 150C output sound waves can be synchronized.

[0057] The D / A converter 43 converts a digital audio signal generated by the control unit 130 (described later) into an analog signal. Audio includes frequencies audible to humans, ultrasonic frequencies higher than audible frequencies, and infrasound frequencies lower than audible frequencies. Audio is an example of sound waves.

[0058] The amplifier 42 amplifies the analog audio signal. If an ultrasonic speaker is used as the speaker 41, a square wave of digital output can be output as is. In other words, a logic output may be used instead of an analog output, and a buffer circuit may be provided instead of the D / A converter 43 and the amplifier 42.

[0059] The speaker 41 outputs an analog audio signal amplified by the amplifier 42 as a sound wave. The speaker 41 is installed, for example, facing the straight-ahead direction of the autonomous mobile device 100, and outputs sound waves in the straight-ahead direction of the autonomous mobile device 100. That is, the sound transmission unit 150C outputs sound waves in one direction (for example, the straight-ahead direction) that serves as a reference for the autonomous mobile device 100. Note that the range in which the speaker 41 outputs sound waves only needs to include the straight-ahead direction of the autonomous mobile device 100, and the central axis of the speaker 41 may be different from the straight-ahead direction (forward) of the autonomous mobile device 100. Hereinafter, the "straight-ahead direction" may also be referred to as "forward."

[0060] The sound receiving units 150L and 150R are attached to the body 190 of the autonomous mobile device 100, receive sound waves reflected by objects around the autonomous mobile device 100, and convert the sound waves into electrical signals. The sound receiving unit 150L (sound wave receiving unit) is provided facing leftward from the front of the autonomous mobile device 100. The sound receiving unit 150R (sound wave receiving unit) is provided facing rightward from the front of the autonomous mobile device 100. In other words, two sound receiving units are provided, and are arranged facing in symmetrical directions with respect to one direction (for example, the front) that serves as a reference for the autonomous mobile device 100.

[0061] One of the sound receiving units 150L receives sound waves from the left side relative to the front of the autonomous mobile device 100. The other sound receiving unit 150R receives sound waves from the right side relative to the front of the autonomous mobile device 100. The two sound receiving units 150L, ​​150R are sound wave receiving units that receive sound waves from different directions. Each of the sound receiving units 150L, ​​150R includes a microphone 51L, 51R and an A / D conversion unit 53L, 53R.

[0062] The microphones 51L and 51R receive sound waves reflected by objects and convert them into electrical audio signals. The left microphone 51L is positioned so as to face, for example, 30 degrees to the left from the front of the autonomous mobile device 100. The right microphone 51R is positioned so as to face, for example, 30 degrees to the right from the front of the autonomous mobile device 100.

[0063] The microphones 51L and 51R may be arranged on either side of the speaker 41 in the left-right direction perpendicular to the front of the autonomous mobile device 100. In other words, the speaker 41 may be located between the microphones 51L and 51R in the vehicle width direction. The orientation of the microphones 51L and 51R is not limited to an angle as long as it is between the front of the autonomous mobile device 100 and the left-right direction. The two microphones 51L and 51R may be arranged facing in different directions. When the autonomous mobile device 100 moves in a three-dimensional space such as a drone, for example, the audio receiving units may be arranged in four locations on the left, right, top, bottom, and right of the autonomous mobile device 100. In this case, it is preferable to install the microphones in four locations on the front side of the autonomous mobile device 100: top, bottom, left, and right.

[0064] The A / D converters 53L and 53R digitize the analog audio signals output from the microphones 51L and 51R, respectively, and output the digitized signals to the control unit 130.

[0065] The storage unit 140 can include an echo signal storage unit 31 and a control result storage unit 33 .

[0066] The echo signal storage unit 31 stores the echo signals measured by the echo signal measurement unit 21, which will be described later. Here, the term "echo signal" refers to a phenomenon in which a sound is reflected from the surface of an object and can be heard again, and is a concept that includes "reverberation," which refers to a phenomenon in which a sound continues to be heard even after the sound source has stopped vibrating due to repeated reflections from the ceiling, walls, etc.

[0067] The control result storage unit 33 stores the control results obtained by the reliability determination unit 25, which will be described later.

[0068] The contact determination unit 136 includes an echo signal measurement unit 21 , a movement direction setting unit 24 , a reliability determination unit 25 , and a sound signal generation unit 26 .

[0069] The audio signal generating unit 26 generates an audio signal of a predetermined frequency and outputs the generated audio signal to the audio transmitting unit 150C at predetermined time intervals (for example, every one second).

[0070] The audio signal generation unit 26 changes the frequency of the audio signal as necessary. For example, if another mobile device is transmitting an audio signal in addition to the autonomous mobile device 100 and the frequency of this audio signal is similar to or coincides with the frequency of the audio signal transmitted by the audio transmission unit 150C of the autonomous mobile device 100, the audio signal generation unit 26 changes the frequency of the audio signal transmitted from the audio transmission unit 150C so that the frequency is different from that of the audio signal transmitted from the other mobile device.

[0071] The echo signal measuring unit 21 receives the audio signals output from the A / D converters 53L and 53R, and transfers them to the echo signal storage unit 31 and the movement direction setting unit 24, respectively.

[0072] When an obstacle is present in the direction in which the autonomous mobile device 100 is traveling, the movement direction setting unit 24 analyzes the voice signal transferred from the echo signal measurement unit 21 and the data stored in the echo signal storage unit 31 and the control result storage unit 33, and sets the movement direction of the autonomous mobile device 100. Furthermore, the movement direction setting unit 24 calculates traveling information such as the turning direction, turning angle, and traveling speed of the autonomous mobile device 100. Note that when there are multiple arrival directions of the output information, the movement direction setting unit 24 does not set a traveling direction, but provides various information such as the multiple arrival directions to the reliability determination unit 25.

[0073] The reliability determination unit 25 determines the reliability based on various information obtained from the movement direction setting unit 24, and outputs various drive signals such as the reliability to the operation control unit 135. The drive signals include information related to drive such as the movement direction, turning direction, turning angle, and running speed in addition to the reliability.

[0074] The reliability determination unit 25 outputs the control signal output to the drive unit 160 to the control result storage unit 33. The control result storage unit 33 stores the control signal output from the reliability determination unit 25.

[0075] Next, a method for setting the movement direction by the movement direction setting unit 24 when the autonomous mobile device 100 avoids an obstacle will be described.

[0076] (First Setting Method) The movement direction setting unit 24 sets the movement direction of the autonomous mobile device 100 based on the received echo signal. The movement direction setting unit 24 outputs information on the set movement direction to the reliability determination unit 25.

[0077] For example, when the autonomous mobile device 100 autonomously travels from position P0 to destination P1 shown in FIG. 2, if an obstacle p2 is present on the travel path x0, which is the shortest route, the autonomous mobile device 100 changes its travel direction at position P2 just before the obstacle p2 to avoid the obstacle p2. In this case, the travel path x2 to the right of the obstacle p2 is a complex and intricate space, and the autonomous mobile device 100 is subject to many restrictions due to the obstacle when traveling. Therefore, it is preferable to change the travel direction of the autonomous mobile device 100 to the left. Therefore, the contact determination unit 136 in FIG. 5 determines the surrounding obstacles and complex space, calculates reliability, and provides a drive signal including the reliability to the operation control unit 135.

[0078] (Second Setting Method) The movement direction setting unit 24 acquires previously received echo signals stored in the echo signal storage unit 31 and past control signals stored in the control result storage unit 33 .

[0079] The movement direction setting unit 24 performs machine learning on the left and right voice receiving units 150L, ​​150R based on past control signals output by the reliability determining unit 25. By performing machine learning, the movement direction setting unit 24 acquires a correlation between the echo signal and the movement direction when the autonomous mobile device 100 avoids an obstacle. Note that machine learning is a well-known technology, so a detailed description thereof will be omitted.

[0080] The movement direction setting unit 24 sets the optimal movement direction of the autonomous mobile device 100 based on the obtained correlation, and the reliability determining unit 25 determines the reliability based on the machine learning result.

[0081] The reliability determination unit 25 uses machine learning results based on past control performance to set driving information such as the moving direction, turning direction, turning angle, and driving speed of the autonomous mobile device 100, and outputs a drive command along with the reliability to the drive unit 160. As a result, when the autonomous mobile device 100 travels while avoiding obstacles, it is possible to select a more open driving path and cause the autonomous mobile device 100 to travel.

[0082] According to the above configuration, in an autonomous mobile device 100 such as an automated guided vehicle, SLAM eliminates the need for expensive equipment such as cameras or LiDAR, allowing for a simple configuration and reducing manufacturing costs. Furthermore, there is no need to create a map of the location or layout when the autonomous mobile device 100 is installed in a new location or each time the layout of a previous location is changed, thereby reducing installation costs. There is also no need to pre-plan a travel path. There is no need to lay magnetic tape, magnetic bars, or two-dimensional codes on the floor for guidance, as with an automatic guided vehicle (AGV). There is no need for the massive data processing and the associated expensive computers required by an autonomous mobile robot (AMR), thereby reducing power consumption.

[0083] The autonomous mobile device 100 may further be equipped with a short-range ranging sensor, a depth camera, a stereo camera, and a bumper sensor or contact sensor that detects a collision with an obstacle, to prevent contact with the nearest obstacle (for example, within 50 cm). When the autonomous mobile device 100 is applied to an automated guided vehicle, it goes without saying that the autonomous mobile device 100 has the functionality to satisfy the regulations related to ISO 3691-4 / JIS D 6802 "Automated guided vehicles and automated guided vehicle systems -- Safety requirements and verification," which are related to the safety of automated guided vehicles.

[0084] (Speaker and Microphone Embodiments) As described above, there are various embodiments for the number of speakers and microphones related to echolocation, the orientation of the speakers and microphones relative to the vehicle body 190, and the layout on the vehicle body 190. Another embodiment of the speaker and microphone is a combination unit for the autonomous mobile device 100 in which a microphone and a speaker are arranged on a single housing (package). A speaker-microphone combination unit, which is one component of the autonomous mobile device 100, is fixed on the vehicle body 190 provided for the autonomous mobile device 100. By electrically connecting wiring such as signal lines and power lines between the combination unit and other components provided for the autonomous mobile device 100, such as the control unit 130, memory unit 140, or drive unit 160, the autonomous mobile device 100 can be manufactured using the speaker-microphone combination unit as a component. Below, an autonomous mobile device 100 and a speaker-microphone combination unit 300 will be described as an embodiment of a speaker and microphone related to echolocation. In the following embodiments, the configuration of the autonomous mobile device 100 other than the speaker and microphone is the same as the configuration of the autonomous mobile device 100 already described with reference to Figures 3 and 5, and therefore will not be described again.

[0085] First Embodiment In the first embodiment, a speaker and microphone layout for increasing the difference in sound pressure between sound waves received by a pair of left and right microphones 51L, 51R will be described with reference to Figures 6A to 7D and 8. Figures 6A to 7D show an embodiment of an autonomous mobile device 100, and Figure 8 shows an embodiment of a speaker-microphone combination unit 300 for an autonomous mobile device.

[0086] As shown in FIGS. 6A to 6C , the autonomous mobile device 100 includes a vehicle body 190, a first speaker 41 attached to the vehicle body 190 and transmitting sound waves toward a region including the front of the vehicle body 190 (positive direction of the X-axis), and a first microphone 51L and a second microphone 51R attached to the vehicle body 190 and receiving sound waves reflected by objects around the autonomous mobile device 100 and converting the sound waves into electrical signals. The first speaker 41 corresponds to the speaker 41 in FIG. 5 . The first microphone 51L and the second microphone 51R correspond to the microphones 51L and 51R in FIG. 5 , respectively. Here, a vehicle having four wheels is exemplified as the mobile unit 170. As long as the region from which the first speaker 41 outputs sound waves includes the front of the autonomous mobile device 100 (positive direction of the X-axis), the central axis of the first speaker 41 may be different from the front of the autonomous mobile device 100.

[0087] The forward direction (straight ahead direction) of the autonomous mobile device 100 and the opposite direction, that is, the front-to-back direction, are defined as the X-axis direction, the vehicle width direction (left-to-right direction), which is the direction perpendicular to the front-to-back direction in a horizontal plane, is defined as the Y-axis direction, and the up-down direction (vertical direction), which is perpendicular to both the front-to-back direction (X-axis direction) and the vehicle width direction (Y direction), is defined as the Z-axis direction.

[0088] The first speaker 41, the first microphone 51L, and the second microphone 51R are located on the outside or outer periphery of the vehicle body 190 when viewed vertically. "Outside of the vehicle body 190" refers to the outer region of the vehicle body 190 when the entire vehicle body 190 when viewed vertically is divided into an outer region including the outer edge of the vehicle body 190 and an inner region surrounded by the outer region. "Outer periphery of the vehicle body 190" refers to the region other than the vehicle body 190 that surrounds the outside of the outer edge of the vehicle body 190 when viewed vertically. Figures 6A to 6C all show examples in which the first speaker 41, the first microphone 51L, and the second microphone 51R are arranged on the outside of the vehicle body 190. Figures 7A to 7D all show examples in which parts of the first and second speakers 41L, 41R are arranged on the outer periphery of the vehicle body 190.

[0089] The first speaker 41, the first microphone 51L, and the second microphone 51R may be disposed on the front side of the vehicle body 190 in the longitudinal direction. This shortens the distance to objects ahead (positive direction of the X-axis), thereby increasing the sound pressure of the sound waves received by the first microphone 51L and the second microphone 51R. The direction in which the first speaker 41 outputs sound waves and the direction in which the first microphone 51L and the second microphone 51R receive sound waves may be within a range from the front to the left and right directions of the autonomous mobile device 100, and may be directed toward the outside of the vehicle body 190. This allows sound waves arriving not only from the front but also from diagonal left and right directions and from the left and right sides to be received. This makes it possible to avoid collisions with surrounding objects when the autonomous mobile device 100 turns.

[0090] The first speaker 41 is located between the first microphone 51L and the second microphone 51R in the left-right direction (Y-axis direction). In other words, the first microphone 51L and the second microphone 51R are arranged so as to sandwich the first speaker 41 between them in the left-right direction (Y-axis direction). This allows the first microphone 51L and the second microphone 51R to be located farther away from the first speaker 41 in the left-right direction, thereby increasing the sound pressure difference between the sound waves received by the first microphone 51L and the second microphone 51R.

[0091] The left-right distances from the first speaker 41 to each of the microphones 51L and 51R are equal. This makes it possible to suppress a difference between the left and right sound pressures of the sound waves received by the microphones 51L and 51R. The autonomous mobile device 100 may be equipped with two or more speakers. In this case, the left-right distances from the centers of gravity of multiple speakers, including the first speaker 41, to each of the microphones 51L and 51R are equal. For example, as shown in FIGS. 7A to 7D , the autonomous mobile device 100 may be equipped with not only the first speaker 41L but also the second speaker 41R. In this case, the left-right distances from the centers of gravity C1 of the first speaker 41L and the second speaker 41R to each of the microphones 51L and 51R are equal.

[0092] As described above, the first speaker 41, the first microphone 51L, and the second microphone 51R are located on the outside or outer periphery of the vehicle body 190 when viewed from above in the vertical direction, the first speaker 41 is located between the first microphone 51L and the second microphone 51R in the left-right direction (Y-axis direction), and the left-right distances from the first speaker 41 to the first and second microphones 51L, 51R are equal. This makes it possible to increase the difference in sound pressure between the sound waves received by the left-right pair of first and second microphones 51L, 51R.

[0093] In the first embodiment, as shown in Figures 6A to 6C, the first speaker 41 faces forward (positive direction of the X-axis) of the autonomous mobile device 100. The first speaker 41L and the second speaker 41R may face diagonally forward to the left and diagonally forward to the right, respectively (Figure 6A), toward the left and right, respectively (Figure 6B), or forward (Figure 6C). In order to eliminate a discrepancy in sound pressure between the left and right, the orientations of the first microphone 51L and the second microphone 51R may be symmetrical with respect to the center C1 in the left-right direction of the vehicle body 190.

[0094] In the first embodiment, as shown in FIGS. 7A to 7D , the autonomous mobile device 100 may further include a second speaker 41R attached to the vehicle body 190 and transmitting sound waves forward (the positive direction of the X axis). In this case, the center of gravity C1 of the first speaker 41L and the second speaker 41R may be located between the first microphone 51L and the second microphone 51R in the left-right direction (the Y axis direction). The left-right distances from the centers of gravity of the first speaker 41L and the second speaker 41R to the first and second microphones 51L and 51R are equal. This reduces the left-right discrepancy in the sound pressure of the sound waves received by the first and second microphones 51L and 51R. The first speaker 41L and the second speaker 41R may be arranged symmetrically with respect to a central plane (target plane) C1 in the left-right direction of the vehicle body 190. The orientations of the first speaker 41L and the second speaker 41R may be symmetrical with respect to the center plane C1 in the left-right direction of the vehicle body 190. The first speaker 41L and the first microphone 51L shown in FIG. 7A are mounted in the same position and facing the same forward direction. In this case, the first speaker 41L and the first microphone 51L can be configured as a single module (a dual-purpose sensor for transmission and reception). The same applies to the second speaker 41R and the second microphone 51R.

[0095] As shown in FIGS. 7A to 7D , at least a portion of the first speaker 41L and the second speaker 41R is disposed on the "outer periphery of the vehicle body 190." At least a portion of the first speaker 41L and the second speaker 41R protrudes forward from the front end F1 of the vehicle body 19. This reduces the distance to surrounding objects, thereby increasing the sound pressure of the sound waves received by the first and second microphones 51L and 51R. Furthermore, if the first and second speakers 41L and 41R are disposed inside the vehicle body 190 rather than on the outer periphery of the vehicle body 190, the emitted sound waves may be reflected by the surface of the vehicle body 190. In this case, the first and second microphones 51L and 51R may receive sound waves that are not reflected by an obstacle, causing the autonomous mobile device 100 to malfunction or recognize incorrectly. By arranging at least a portion of the first speaker 41L and the second speaker 41R on the "outer periphery of the car body 190", it is possible to reduce the sound pressure of sound waves reflected by the car body 190 itself, which causes noise.

[0096] The first and second speakers 41L, 41R may be magnetic speakers or piezoelectric speakers. The first and second microphones 51L, 51R may be capacitor microphones or piezoelectric sensors. As shown in FIG. 7A , when the speaker and microphone are positioned in the same location and facing the same direction, the speaker-microphone pair may form a single module. The first and second speakers 41L, 41R may be controlled to output ultrasonic waves at the same time. The size of the first and second speakers 41L, 41R and the first and second microphones 51L, 51R is approximately 1 mm to 30 mm, while the width (lateral length) of the vehicle body 190 is assumed to be approximately 20 cm to 1 m. In the drawings, the size of the first and second speakers 41L, 41R and the first and second microphones 51L, 51R relative to the size of the vehicle body 190 is exaggerated. 6A to 6C, the first and second microphones 51L and 51R are each 2.5 cm or more away from the first speaker 41 in the left-right direction (Y-axis direction). The first and second microphones 51L and 51R are 5 cm or more away from each other in the left-right direction (Y-axis direction). Note that the signals received by the first and second microphones 51L and 51R are processed within the same control unit 130, as shown in FIGS. 3 to 5.

[0097] 8, the autonomous mobile device 100 may include a vehicle body 190, wheels 170, a storage unit 140, a drive unit 160, and a speaker / microphone combination unit 300 for the autonomous mobile device. The vehicle body 190, wheels 170, storage unit 140, and drive unit 160 have been described with reference to FIGS. 3 and 5, so a repeated description will be omitted here. The combination unit 300 is attached to the front end F1 of the vehicle body 190.

[0098] The speaker-microphone combination unit 300 for an autonomous mobile device is a combination unit 300 equipped with a speaker and a microphone used in the autonomous mobile device 100 described above. The combination unit 300 includes a housing 210 that forms the outer shape of the combination unit 300, a first speaker 41 attached to the housing 210 and transmitting sound waves toward the front of the combination unit 300 (positive direction of the X axis), and a first microphone 51L and a second microphone 51R attached to the housing 210 and receiving sound waves reflected by objects around the combination unit 300 and converting the sound waves into electrical signals. The first speaker 41 and the first and second microphones 51L, 51R are located outside or on the outer periphery of the housing 210 when the combination unit 300 is viewed vertically. The first speaker 41 is located between the first and second microphones 51L, 51R in the left-right direction (Y axis direction) perpendicular to the front (positive direction of the X axis). The distances in the left-right direction (Y-axis direction) from the center of gravity of the first speaker 41 or a plurality of speakers including the first speaker 41 to the first and second microphones 51L and 51R are equal.

[0099] The first speaker 41 may be disposed at a front end F2 of the housing 210. The combined unit 300 may be fixed to the vehicle body 190 so that the front end F2 of the housing 210 coincides with the front end F1 of the vehicle body 190. The housing 210 may be made of, for example, metal or resin.

[0100] By replacing the "car body 190" shown in Figures 6A to 7D with the "housing 210" in Figure 8, the combined unit shown in Figure 8 can have the same speaker and microphone layout as Figures 6A to 7D. In this way, the embodiments described with reference to Figures 6A to 7D and the embodiments of the autonomous mobile device 100 described below can be applied to the combined unit 300. Conversely, by replacing the "housing 210" with the "car body 190", the embodiments of the combined unit 300 described below can also be applied to the autonomous mobile device 100. In other words, by replacing the "car body 190" with the "housing 210", the embodiments of the autonomous mobile device 100 and the combined unit 300 can be applied to each other.

[0101] Although Figure 8 shows an example in which the composite unit 300 has the control unit 130 (see Figures 3 to 5) inside the housing 210, the control unit 130 may be mounted on the vehicle body 190 instead of inside the composite unit 300.

[0102] Second Embodiment In the second embodiment, with reference to FIGS. 7E to 7H, the layout of the first speaker 41 and the combined unit 300 for increasing the sound pressure of sound waves received by the first and second microphones 51L, 51R from the front or diagonally forward direction will be described. FIGS. 7E and 7F show an embodiment of the autonomous mobile device 100, and FIGS. 7G and 7H show an embodiment of the combined unit 300. As shown in FIGS. 7E and 7F and 7G and 7H, the combined unit 300 is disposed at the front end F1 of the vehicle body 190. The first speaker 41 or the combined unit 300 is disposed at the end F1 of the vehicle body 190 in the forward direction (positive direction of the X-axis), which is the direction of travel of the autonomous mobile device. This shortens the distance to an object located in front or diagonally forward direction, increasing the sound pressure of sound waves reflected from the object. Furthermore, it is possible to reduce echo signals from the vehicle body 190 itself, which cause noise, rather than echo signals from obstacles.

[0103] 6A to 6C, the first speaker 41 may be disposed at the front end F1 of the vehicle body 190, and the first and second microphones 51L, 51R may be disposed behind the first speaker 41 or at the same longitudinal position as the first speaker 41. This makes it possible to reduce the sound pressure of sound waves directly received by the first and second microphones 51L, 51R from the first speaker 41.

[0104] As shown in FIGS. 7E to 7H , in order to avoid a collision between the first speaker 41 or the combination unit 300 and an object, the autonomous mobile device 100 may further include a contact detection sensor 214 that detects contact with an object and is disposed forward of the first speaker 41 or the combination unit 300 (in the positive direction of the X-axis). The car body 190 and the first speaker 41 are not disposed forward of the contact detection sensor 214. The contact detection sensor 214, the first speaker 41 or the combination unit 300, and the car body 190 are disposed in this order from the front. The contact point of the contact detection sensor 214 is disposed forward of the first speaker 41 or the combination unit 300. When contact with an object is detected, the autonomous mobile device 100 immediately stops. By stopping the autonomous mobile device 100 before colliding with the first speaker 41 or the combination unit 300, a collision between the first speaker 41 or the combination unit 300 and the object can be avoided. Any type of contact detection sensor may be used for the contact detection sensor 214. The contact detection sensor 214 may be disposed at the same position in the front-to-rear direction (X-axis direction) as the first speaker 41 or the combination unit 300. This makes it possible to reduce the severity of a collision between the first speaker 41 or the combination unit 300 and an object.

[0105] As shown in FIGS. 7E and 7G , a part or the entirety of the first speaker 41 or the composite unit 300 may protrude from the front end F1 of the vehicle body 190. The first speaker 41 is disposed at the front end F1 of the vehicle body 190. When viewed vertically, the first speaker 41 or the composite unit 300 may be disposed on the outer periphery of the vehicle body 190 ( FIGS. 7E and 7G ). Alternatively, as shown in FIGS. 7F and 7H , the entirety of the first speaker 41 or the composite unit 300 may be disposed inside the vehicle body 190 relative to the front end F1 of the vehicle body 190. When viewed vertically, the first speaker 41 or the composite unit 300 may be disposed outside the vehicle body 190 ( FIGS. 7F and 7H ). The position of the contact detection sensor 214 relative to the vehicle body 190 also changes depending on the position of the first speaker 41 or the composite unit 300 relative to the vehicle body 190. The second embodiment can be implemented in combination with one or more other embodiments.

[0106] Third Embodiment In the third embodiment, the structure of a vehicle body 190 or a housing 210 for reducing the sound pressure of sound waves (noise) arriving from behind will be described with reference to Figures 9 to 12. Figure 9 shows an example of a combined unit 300, and is a plan view illustrating the structure of a housing 210 for reducing the sound pressure of sound waves (noise) arriving from behind among the sound waves received by the first and second microphones 51L and 51R. The housing 210 has sound pressure reduction units 210aL and 210aR arranged behind the first and second microphones 51L and 51R, which reduce the sound pressure of transmitted and diffracted sound waves.

[0107] As shown in FIG. 9 , the housing 210 has a convex planar shape with a central portion in the left-right direction (Y-axis direction) protruding forward (positive direction of the X-axis). The first and second microphones 51L and 51R are disposed in openings formed in the sidewalls of the housing 210 at the convex portion. The first and second microphones 51L and 51R are attached facing outward from the housing 210 in the left-right direction. Behind the first and second microphones 51L and 51R, sound pressure reduction units 210aL and 210aR are disposed as part of the housing 210. These units block or reduce the sound pressure of sound waves S3 arriving from the rear from being directly incident on the microphones. A portion of the sound wave S1 output from the first speaker 41 is reflected rearward by an object 60A as a sound wave S2, and a portion of the sound wave S2 is reflected rearward by an object 60B disposed rearward of the combination unit 300 as a sound wave S3 toward the combination unit 300 (first microphone 51L) located in front of the combination unit 300. The sound pressure reduction unit 210aL, located behind the first microphone 51L, blocks the sound waves S3 from directly entering the microphone or reduces their sound pressure. Of the sound waves received by the first and second microphones 51L, 51R, sound waves arriving from behind are not necessary for the autonomous mobile device 100 to travel. The sound pressure reduction unit 210aL can reduce the sound pressure of sound waves (noise) arriving from behind among the sound waves received by the first microphone 51L. Because the housing 210 has a shape that is symmetrical with respect to the center in the left-right direction, the sound pressure reduction unit 210aR can reduce the sound pressure of sound waves (noise) arriving from behind among the sound waves received by the second microphone 51R.

[0108] 10A to 10D are plan views showing modified examples for reducing the sound pressure of sound waves (noise) arriving from behind. As shown in FIG. 10A, by positioning the first microphone 51L facing sideways (in the Y direction) inside the housing 210 relative to the opening of the housing 210, a portion of the housing 210 located behind the first microphone 51L functions as a sound pressure reduction unit 210aL. As shown in FIG. 10B, the first microphone 51L is in the same position as in FIG. 10A, but by orienting the first microphone 51L diagonally forward, the sound pressure of sound waves (noise) arriving from behind can be reduced. Furthermore, as shown in FIG. 10C, even if the housing 210 does not have an opening, a portion of the housing 210 having a convex shape can function as a sound pressure reduction unit 210aL. 10D, if the housing 210 has an opening facing diagonally forward, by attaching a first microphone 51L facing diagonally forward to the opening, a part of the housing 210 located behind the first microphone 51L can function as a sound pressure reduction section 210aL. Although the left side portion of the housing 210 and the first microphone 51L have been described in Figures 10A to 10D, because the combined unit 300 has a symmetrical planar shape, the right side portion of the housing 210 and the second microphone 51R also have a configuration similar to that of the left side portion.

[0109] Fig. 11 is a plan view showing a modified example of an embodiment in which the sound pressure of sound waves (noise) arriving from behind is reduced. In the example shown in Fig. 11, the first and second microphones 51L and 51R face forward. As in Fig. 9, the first and second microphones 51L and 51R receive sound waves from an opening in the housing 210. Parts of the housing 210 located behind the first and second microphones 51L and 51R function as sound pressure reduction units 210aL and 210aR.

[0110] FIG. 12 is a plan view showing a modified example of an embodiment for reducing the sound pressure of sound waves (noise) arriving from the rear. In the example shown in FIG. 12, an opening of the housing 210 is formed diagonally forward, and the first and second microphones 51L and 51R are attached to the opening facing diagonally forward. As in FIG. 9, the first and second microphones 51L and 51R receive sound waves from the opening of the housing 210. A portion of the housing 210 located behind the first and second microphones 51L and 51R functions as a sound pressure reduction unit 210aL and 210aR. Note that while FIGS. 11 and 12 show a combined unit 300 in which a control unit 130 is disposed inside the housing 210, the combined unit 300 may not include the control unit 130.

[0111] In the third embodiment, an example of the combined unit 300 has been described with reference to Figures 9 to 12, but it is also possible to implement the embodiment by replacing the housing 210 in the combined unit 300 with the vehicle body 190 in the autonomous mobile device 100. This makes it possible to provide an autonomous mobile device 100 that achieves the same effects as the combined unit 300 described above. The third embodiment can be implemented in combination with one or more other embodiments.

[0112] (Fourth embodiment) In the fourth embodiment, with reference to Figures 13 to 17B, the structure of the composite unit 300 and the autonomous mobile device 100 that increases the sound pressure of sound waves that arrive at the pair of left and right microphones 51L, 51R from diagonally forward among the sound waves received by the first and second microphones 51L, 51R will be described.

[0113] 13 is a plan view showing an example of the structure of a combined unit 300 that increases the sound pressure of sound waves arriving from diagonally forward among the sound waves received by the first and second microphones 51L, 51R. The combined unit 300 further includes a first reflecting member 211L that reflects sound waves and is at least partially disposed behind the first microphone 51L, and a second reflecting member 211R that reflects sound waves and is at least partially disposed behind the second microphone 51R. The reflecting member is, for example, a plate-shaped member (reflecting plate) having a reflective surface.

[0114] The first and second microphones 51L and 51R face in the left-right direction and toward the outside of the housing 210. This allows them to receive sound waves arriving from outside the housing 210.

[0115] The reflecting surfaces of the first and second reflecting members 211L and 211R face forward (positive direction of the X-axis). This allows the first and second reflecting members 211L and 211R to reflect sound waves arriving from the diagonal front toward the first and second microphones 51L and 51R. This increases the sound pressure of the sound waves arriving from the diagonal front and received by the first and second microphones 51L and 51R. The reflecting surfaces of the first and second reflecting members 211L and 211R are formed on surfaces facing the first and second microphones 51L and 51R. The reflecting surfaces may be flat as shown in FIG. 13 or hemispherical. In the case of a flat shape, the reflecting surfaces are oriented at an angle that reflects sound waves arriving from the diagonal front toward the microphones 51L and 51R. In the case of a spherical shape, the position and orientation of the reflecting surface are set so that the reflected sound waves converge at the positions of the microphones 51L and 51R.

[0116] A portion of the sound wave S1 output from the first speaker 41 is reflected by the object 60A toward the first reflecting member 211L as a sound wave S2, and the sound wave S2 is reflected by the first reflecting member 211L toward the first microphone 51L located in front. The sound pressure of the sound wave S2 arriving at the first microphone 51L from diagonally forward can be increased. Because the combined unit 300 has a bilaterally symmetrical planar shape, it can also increase the sound pressure of the sound wave arriving at the second microphone 51R from diagonally forward.

[0117] The reflecting surfaces of the first and second reflecting members 211L and 211R do not have to face directly forward (the positive direction of the X-axis). That is, the reflecting surfaces do not have to be exactly perpendicular to the forward direction (the positive direction of the X-axis). As shown in FIG. 13 , the reflecting surfaces of the first and second reflecting members 211L and 211R may be inclined toward the center of the housing 210 in the left-right direction. This allows the first reflecting member 211L to reflect the sound wave S2 reflected by an object 60A located diagonally forward toward the first microphone 51L, as shown in FIG. 13 .

[0118] Fig. 14A shows an example of the structure of the autonomous mobile device 100 that increases the sound pressure of sound waves arriving from diagonally forward among the sound waves received by the first and second microphones 51L, 51R. While Fig. 13 shows an example of the combined unit 300, Fig. 14A shows an example of the autonomous mobile device 100 in which the speaker 41 and the microphones 51L, 51R are each individually attached to the vehicle body 190.

[0119] The first speaker 41 is disposed in a speaker housing 220C, the first microphone 51L is disposed in a first microphone housing 220L, and the second microphone 51R is disposed in a second microphone housing 220R. The speaker housing 220C, the first microphone housing 220L, and the second microphone housing 220R are mounted on the vehicle body 190. Note that a circuit unit 151C including an amplifier 42 and a D / A conversion unit 43 may be disposed in the housing 220C. Circuit units 151L and 151R including A / D conversion units 53L and 53R may be disposed in each of the housings 220L and 220R, respectively.

[0120] The positions and orientations of the first microphone 51L and the second microphone 51R relative to the vehicle body 190 in Fig. 14A are the same as the positions and orientations of the first and second reflecting members 211L, 211R relative to the first microphone 51L and the second microphone 51R in Fig. 14A are also the same as those in Fig. 13.

[0121] 14A shows an example in which the housings 220C, 220L, and 220R are disposed on the outside of the vehicle body 190, and the first speaker 41 and the first and second microphones 51L and 51R are disposed on the outside of the vehicle body 190. That is, the first speaker 41 and the first and second microphones 51L and 51R are disposed inside the outer edge of the vehicle body 190. However, as shown in FIG. 14B , the housings 220C, 220L, and 220R, the first speaker 41, and the first and second microphones 51L and 51R may be disposed on the outer periphery of the vehicle body 190, i.e., outside the outer edge of the vehicle body 190. In this case, the first speaker 41 is positioned forward of the front end F1 of the vehicle body 190, which shortens the distance to an object in front, thereby increasing the sound pressure of sound waves reflected by the object. Furthermore, it is possible to reduce echo signals from the vehicle body 190 itself, which become noise, rather than echo signals from obstacles (forward objects). Because the first and second microphones 51L, 51R are arranged on the outer periphery of the vehicle body 190 in the left-right direction, the distance between the first and second microphones 51L, 51R is even longer than in FIG. 14A. Therefore, as described in the first embodiment, it is possible to further increase the difference in sound pressure between the left and right sound waves. The contact detection sensor 214 shown in FIGS. 7E to 7H may be added to the autonomous mobile device 100 shown in FIGS. 14A and 14B.

[0122] 15A shows another example of the structure of the autonomous mobile device 100, which increases the sound pressure of sound waves arriving from diagonally forward among the sound waves received by the first and second microphones 51L and 51R. Figures 15A and 15B show an example in which the first and second microphones 51L and 51R face forward (positive direction of the X-axis).

[0123] The autonomous mobile device 100 further includes a first reflecting member 212L that reflects sound waves and is at least partially disposed inside the vehicle body 190 in the left-right direction (Y-axis direction) of the first microphone 51L, and a second reflecting member 212R that reflects sound waves and is at least partially disposed inside the vehicle body 190 in the left-right direction of the second microphone 51R. The reflecting surfaces of the first and second reflecting members 212L, 212R face outward in the left-right direction. The reflecting surfaces of the first and second reflecting members 212L, 212R are formed on surfaces facing the first microphone 51L and the second microphone 51R. This allows the first and second reflecting members 212L, 212R to reflect sound waves arriving from diagonally forward toward the first and second microphones 51L, 51R. Therefore, the sound pressure of the sound waves arriving from the diagonal front and received by the first microphone 51L and the second microphone 51R can be increased. The reflecting surface may be flat as shown in Figures 15A and 15B, or may be a hemispherical spherical shape. In the case of a flat shape, the orientation of the reflecting surface is set at an angle that reflects the sound waves arriving from the diagonal front toward the microphones 51L and 51R. In the case of a spherical shape, the position and orientation of the reflecting surface are set so that the reflected sound waves converge at the positions of the microphones 51L and 51R.

[0124] The reflecting surfaces of the first and second reflecting members 212L and 212R do not have to face directly outward in the left-right direction (Y-axis direction). That is, the reflecting surfaces do not have to be exactly perpendicular to the left-right direction (Y-axis direction). As shown in Figures 15A and 15B, the reflecting surfaces of the first and second reflecting members 212L and 212R may be inclined toward the rear (negative direction of the X-axis). This allows the first and second reflecting members 212L and 212R to reflect sound waves reflected by an object located diagonally forward toward the first microphones 51L and 51R.

[0125] 15A are housed in individual housings 220C, 220L, and 220R, similar to those in FIG. 14A. Each housing 220C, 220L, and 220R is disposed outside the vehicle body 190, and the first speaker 41 and the first and second microphones 51L and 51R are disposed outside the vehicle body 190. Alternatively, as shown in FIG. 15B, each housing 220C, 220L, and 220R, the first speaker 41, and the first and second microphones 51L and 51R may be disposed on the outer periphery of the vehicle body 190. In this case, the first speaker 41, the first microphone 51L, and the second microphone 51R are located forward of the front end F1 of the vehicle body 190, thereby shortening the distance to an object ahead and increasing the sound pressure of sound waves reflected by the object. It is also possible to reduce echo signals from the vehicle body 190 itself, which may cause noise.

[0126] 16 shows another example of the structure of the combined unit 300 that increases the sound pressure of sound waves arriving from diagonally forward among the sound waves received by the first and second microphones 51L, 51R. Figures 16 to 17B show an example in which the first and second microphones 51L, 51R face diagonally forward.

[0127] In the composite unit 300 shown in FIG. 16 , the orientations of the first and second microphones 51L and 51R are tilted outward from the housing 210 in the left-right direction (Y-axis direction) rather than forward (positive direction of the X-axis). Specifically, the first microphone 51L is tilted leftward rather than forward. The second microphone 51R is tilted rightward rather than forward. This allows the sound pressure of sound waves arriving from diagonally forward among the sound waves received by the first and second microphones 51L and 51R to be increased. The angle of tilt is, for example, greater than 0 degrees and less than or equal to 90 degrees. The composite unit 300 shown in FIG. 16 further includes first and second reflecting members 211L and 211R arranged around the first and second microphones 51L and 51R. The reflecting surfaces of the first and second reflecting members 211L and 211R are formed on the surfaces facing the first and second microphones 51L and 51R. As a result, the first and second reflecting members 211L, 211R can reflect sound waves arriving from diagonally forward toward the first and second microphones 51L, 51R. Since the first and second microphones 51L, 51R face diagonally forward, the sound pressure of sound waves arriving from diagonally forward can be increased. The combined unit 300 shown in FIG. 12 , which does not include the first and second reflecting members 211L, 211R, also has the first and second microphones 51L, 51R facing diagonally forward, so the sound pressure of sound waves arriving from diagonally forward can be increased. Therefore, the combined unit 300 shown in FIG. 12 is also included in the fourth embodiment.

[0128] 17A and 17B show another example of the structure of the autonomous mobile device 100, which increases the sound pressure of sound waves arriving from diagonally forward among the sound waves received by the first and second microphones 51L and 51R. FIGS. 17A and 17B show an example in which the first and second microphones 51L and 51R face diagonally forward. The first speaker 41, first microphone 51L, and second microphone 51R in FIGS. 17A and 17B are housed in separate housings 220C, 220L, and 220R, similar to FIG. 14A . A circuit unit 151C including an amplifier 42 and a D / A converter 43 may be disposed within the housing 220C. Circuit units 151L and 151R including A / D converters 53L and 53R may be disposed within each housing 220L and 220R, respectively.

[0129] As shown in FIG. 17A , each housing 220C, 220L, 220R may be disposed outside the vehicle body 190 and in contact with the front end F1 of the vehicle body 190. This increases the sound pressure of sound waves arriving from the front. It also reduces noise-causing echo signals from the vehicle body 190 itself. Furthermore, each housing 220L, 220R is in contact with the left-right end of the vehicle body 190. This allows the first and second microphones 51L, 51R to be spaced apart in the left-right direction, thereby increasing the difference in sound pressure between the sound waves received by the pair of left and right microphones 51L, 51R. Portions of the housings 220L, 220R located behind the first and second microphones 51L, 51R function as sound pressure reduction units.

[0130] As shown in FIG. 17B, each housing 220C, 220L, 220R may be disposed on the outer periphery of the vehicle body 190 and may be in contact with the front end F1 of the vehicle body 190. By attaching each housing 220C, 220L, 220R further forward in the vehicle body 190 than in FIG. 17A, the sound pressure of sound waves arriving from the front and received by the first and second microphones 51L, 51R can be increased. It is also possible to reduce echo signals from the vehicle body 190 itself that cause noise. A contact detection sensor 214 shown in FIGS. 7E to 7H may be added to the autonomous mobile device 100 shown in FIGS. 17A and 17B.

[0131] 18A to 18C, a description will be given of the structure of a combined unit 300 that reduces the sound pressure of sound waves arriving from opposite left and right sides among the sound waves received by the first and second microphones 51L, 51R. The left and right pair of first and second microphones 51L, 51R increases the sound pressure of sound waves arriving from the same left and right side and decreases the sound pressure of sound waves arriving from opposite left and right sides, thereby increasing the difference in sound pressure of the sound waves received by the left and right pair of first and second microphones 51L, 51R.

[0132] FIG. 18A is a plan view showing an example of the structure of a combined unit 300 that reduces the sound pressure of sound waves received by the first and second microphones 51L and 51R that arrive from opposite left and right sides. FIGS. 18B and 18C are plan views showing other examples of the structure of a combined unit 300 that reduces the sound pressure of sound waves received by the first and second microphones 51L and 51R that arrive from opposite left and right sides. As shown in FIGS. 18A to 18C , the housing 210 of the combined unit 300 has a first sound pressure reduction section 210bL and a second sound pressure reduction section 210bR. The first sound pressure reduction section 210bL is a part of the housing 210 that reduces the sound pressure of transmitted sound waves and is located outside the housing 210 of a first line segment connecting the first speaker 41 and the first microphone 51L when viewed in the vertical direction (Z-axis direction). The second sound pressure reduction section 210bR is a part of the housing 210 that reduces the sound pressure of sound waves that pass through it and is located outside the housing 210 of a second line segment connecting the first speaker 41 and the second microphone 51R when viewed in the vertical direction. The first sound pressure reduction section 210bL and the second sound pressure reduction section 210bR may be made of the same material as the housing 210, or may be made of a different material from the housing 210, for example, a material that absorbs sound waves. A member that reflects sound waves may be disposed on the surface of the first sound pressure reduction section 210bL and the second sound pressure reduction section 210bR.

[0133] The sound wave S1 output from the first speaker 41 is reflected by an object 60A diagonally forward to the left, and the sound wave S2 of the reflected sound waves heading toward the second microphone 51R is blocked from directly entering the second microphone 51R or its sound pressure is reduced by the second sound pressure reduction unit 210bR. In this way, the sound pressure of the sound waves arriving from opposite left and right sides among the sound waves received by the first and second microphones 51L and 51R can be reduced.

[0134] The first sound pressure reduction unit 210bL and the second sound pressure reduction unit 210bR are also realized in the housings 210, 220C, 220L, and 220R shown in Figures 9, 11, 12, 13, 14A, 14B, 15A, 15B, 16, 17A, and 17B. The fifth embodiment can be implemented in combination with one or more other embodiments. For example, the structure of the combined unit 300 shown in Figures 18A to 18C represents an example that combines the second embodiment, which increases the sound pressure of sound waves received from the front or diagonally forward, the third embodiment, which reduces the sound pressure of sound waves (noise) arriving from behind, and the fourth embodiment, which increases the sound pressure of sound waves arriving from diagonally forward to the pair of left and right microphones 51L and 51R.

[0135] 19 , the structures of a combined unit 300 and an autonomous mobile device 100 that reduce the sound pressure of sound waves (noise) reflected by irregularities 63 in the ground 62, among the sound waves received by the first and second microphones 51L and 51R, will be described. The combined unit 300 further includes a protruding member 213 that protrudes in the traveling direction of the sound waves from the bottom of at least one of the first speaker 41, the first microphone 51L, and the second microphone 51R, and that reduces the sound pressure of the transmitted sound waves.

[0136] The "propagating direction of sound waves" is a concept that includes the direction in which sound waves are output from the first speaker 41 and the direction in which the first microphone 51L and the second microphone 51R receive the sound waves. FIG. 19 shows an example of a combined unit 300 in which the first speaker 41, the first microphone 51L, and the second microphone 51R are mounted on a single housing 210, and in which protruding members 213 protrude forward (in the positive direction of the X-axis) from the bottom surfaces of the first microphone 51L and the second microphone 51R. Alternatively, instead of the combined unit 300, the first speaker 41, the first microphone 51L, and the second microphone 51R may each be individually mounted directly on the vehicle body 190. In this case, the protruding members 213 protrude forward (in the positive direction of the X-axis) from the bottom surfaces of the first speaker 41, the first microphone 51L, and the second microphone 51R. The protruding amount is, for example, 2 cm to 10 cm. The material of the protruding member 213 may be the same as that of the housing 210 or the vehicle body 190, or may be made of a material different from that of the housing 210 or the vehicle body 190, for example, a material that absorbs sound waves or a material that reflects sound waves.

[0137] The sound waves S1 output from the first speaker 41 are reflected by the unevenness 63 of the ground 62 on which the autonomous mobile device 100 is traveling, and the sound waves S2 reflected toward the first microphone 51L or the second microphone 51R have their sound pressure reduced when they pass through the protruding member 213. This makes it possible to reduce the sound pressure of sound waves (noise) reflected by the unevenness 63 of the ground 62, among the sound waves received by the first and second microphones 51L, 51R. Although not shown in the figure, if the protruding member 213 protrudes forward from the bottom surface of the first speaker 41, the sound pressure of the sound waves S1 output from the first speaker 41 is reduced when they pass through the protruding member 213. The sound waves S1 may be reflected by the protruding member 213.

[0138] Seventh Embodiment In the seventh embodiment, with reference to FIG. 20 , the structure of a combined unit 300 and an autonomous mobile device 100 that increases the sound pressure of sound waves arriving from the sides of the autonomous mobile device 100 to prevent entanglement of a lateral object 60A will be described. As shown in FIG. 20 , the entire first reflecting member 211L is disposed behind the first microphone 51L. Similarly, the entire second reflecting member 211R is disposed behind the second microphone 51R. That is, when the first microphone 51L is viewed from the outside in the left-right direction (left side), the entire first microphone 51L is visible without being blocked by the first reflecting member 211L. Similarly, when the second microphone 51R is viewed from the outside in the left-right direction (right side), the entire second microphone 51R is visible without being blocked by the second reflecting member 211R.

[0139] The sound wave S1 output from the first speaker 41 is reflected by the surface of the object 60A located on the left side of the autonomous mobile device 100, and the sound wave S2 reflected toward the first microphone 51L can reach the first microphone 51L without being blocked by the first reflecting member 211L. Therefore, the sound pressure of the sound wave arriving from the side of the autonomous mobile device 100 equipped with the composite unit 300 of Fig. 20 can be increased to detect the object 60A on the side and prevent the autonomous mobile device 100 from entangling the object 60A when turning left. The sensitivity of the first and second microphones 51L, 51R to sound waves arriving from the side of the autonomous mobile device 100 can be increased.

[0140] 13 , 14A , and 14B , the first and second reflecting members 211L and 211R are tilted significantly toward the inside of the composite unit 300 to increase the sound pressure of sound waves arriving at the pair of left and right microphones 51L and 51R from diagonally forward. Therefore, when the first and second microphones 51L and 51R are viewed from the outside in the left-right direction, the first and second reflecting members 211L and 211R obscure portions of the first and second microphones 51L and 51R. In contrast, the example shown in FIG. 20 keeps the tilt angle small, making the entire first and second microphones 51L and 51R visible. However, the first and second reflecting members 211L and 211R may be moved further rearward (in the negative direction of the X axis) while maintaining a large tilt angle, thereby making the entire first and second microphones 51L and 51R visible. By replacing the housing 210 in FIG. 20 with the vehicle body 190, the seventh embodiment can also be applied to the structure of the autonomous mobile device 100.

[0141] The seventh embodiment can be implemented in combination with one or more of the other embodiments. The first and second reflecting members 211L and 211R in FIG. 20 provide the effect of reducing the sound pressure of sound waves (noise) arriving from behind (third embodiment) and the effect of increasing the sound pressure of sound waves arriving at the pair of left and right microphones 51L and 51R from diagonally forward (fourth embodiment). A portion of the housing 210 located outside the line connecting the microphones 51L and 51R and the first speaker 41 functions as a sound pressure reduction section, thereby providing the effect of reducing the sound pressure of sound waves arriving from the opposite left and right sides (fifth embodiment). In other words, the example shown in FIG. 20 is a combination of the third to fifth embodiments.

[0142] Eighth Embodiment In the eighth embodiment, with reference to FIG. 21 , the structure of a combined unit 300 and an autonomous mobile device 100 that increases the sound pressure of sound waves arriving from the front of the autonomous mobile device 100 to prevent collision with objects 60A and 60B in front of the autonomous mobile device 100 will be described. As shown in FIG. 21 , the entire first reflecting member 212L is disposed inside the housing 210 on the left and right sides of the first microphone 51L. Similarly, the entire second reflecting member 212R is disposed inside the housing 210 on the left and right sides of the second microphone 51R. In other words, when the first microphone 51L is viewed from the front, the entire first microphone 51L is visible without being blocked by the first reflecting member 212L. Similarly, when the second microphone 51R is viewed from the front, the entire second microphone 51R is visible without being blocked by the second reflecting member 212R.

[0143] The sound wave S1 output from the first speaker 41 is reflected by the surface of the object 60A located in front of the autonomous mobile device 100, and the sound wave S2 reflected toward the first microphone 51L can reach the first microphone 51L without being blocked by the first reflecting member 212L. Therefore, the sound pressure of the sound wave arriving from the front of the autonomous mobile device 100 can be increased to detect the object 60A in front and prevent a collision with the object 60A. Similarly, the sound wave S3 output from the first speaker 41 is reflected by the surface of the object 60B located in front of the autonomous mobile device 100, and the sound wave S4 reflected toward the second microphone 51R can reach the second microphone 51R without being blocked by the second reflecting member 212R. Therefore, the sound pressure of the sound wave arriving from the front of the autonomous mobile device 100 can be increased to detect the object 60B in front and prevent a collision with the object 60A. The sensitivity of the first and second microphones 51L and 51R to sound waves arriving from the front of the autonomous mobile device 100 can be increased.

[0144] 21 , the first and second reflecting members 212L, 212R have the effect of increasing the sound pressure of sound waves arriving at the pair of left and right microphones 51L, 51R from diagonally forward (fourth embodiment) and the effect of reducing the sound pressure of sound waves arriving from the opposite left and right sides (fifth embodiment). That is, the example shown in Fig. 20 is a combination of the fourth and fifth embodiments. It goes without saying that a part of the housing 210 located behind the first and second microphones 51L, 51R forms a sound pressure reduction section (third embodiment) that reduces the sound pressure of sound waves (noise) arriving from the rear.

[0145] 22A and 22B , a description will be given of the structure of a combined unit 300 and an autonomous mobile device 100 that increases the sound pressure of sound waves arriving at a pair of left and right microphones 51L, 51R from diagonally forward, while also increasing the sound pressure of sound waves arriving from at least one of the front and the side. Fig. 22A is a modified example of the combined unit 300 shown in Figs. 12 and 18C , and is an enlarged plan view of the first microphone 51L and a portion of the housing 210 around it.

[0146] 22A , the portions of the first and second microphones 51L, 51R that receive sound waves may be visible from at least one of the front and left-right directions outside the housing 210. For example, the entire tips of the acoustic horns provided in the first and second microphones 51L, 51R may be visible from at least one of the front (X-axis direction) and left-right directions (Y-axis direction) outside the housing 210. The orientation of the first and second microphones 51L, 51R is tilted more toward the outside of the housing 210 in the left-right direction (Y-axis direction) than toward the front (positive direction of the X-axis).

[0147] In FIGS. 12 and 18C , portions of the first and second microphones 51L, 51R are shielded by the housing 210. Specifically, the edge of the opening of the housing 210 partially conceals the first and second microphones 51L, 51R. In the example of FIG. 22A , the side of the opening of the housing 210 where the first and second microphones 51L, 51R are disposed is inclined so that the opening widens toward the outside of the housing 210. This makes the portions of the first and second microphones 51L, 51R that receive sound waves visible from at least one of the front and left / right directions outside the housing 210. Therefore, it is possible to increase the sound pressure of sound waves arriving at the pair of left and right microphones 51L, 51R from diagonally forward, while also increasing the sound pressure of sound waves arriving from at least one of the front and side.

[0148] 22B is a plan view showing another example of the structure of a combined unit 300 that increases the sound pressure of sound waves arriving at the pair of left and right microphones 51L, 51R from diagonally forward, while also increasing the sound pressure of sound waves arriving from at least one of the front and the side. The combined unit 300 further includes a first reflecting member 211L arranged around the first microphone 51L to reflect sound waves toward a portion of the first microphone 51L that receives the sound waves, and a second reflecting member 211R arranged around the second microphone 51R to reflect sound waves toward a portion of the second microphone 51R that receives the sound waves. As in FIG. 22A , the portions of the first and second microphones 51L, 51R that receive the sound waves are visible from at least one of the front (positive direction of the X axis) and left and right (Y axis) outside the housing 210. By providing the first and second reflecting members 211L, 211R, it is possible to further increase the sound pressure of sound waves arriving at the pair of left and right microphones 51L, 51R from diagonally forward, and also to further increase the sound pressure of sound waves arriving from at least one of the front and the side. Note that the reflecting surfaces of the first and second reflecting members 211L, 211R may face directly outward from the housing 210 in the forward or left-right direction (Y-axis direction), or may be inclined.

[0149] 9, 11, 13, 14A, 14B, 15A, 15B, 16, 18A, 20, and 22B, a convex housing 210 may be formed by, for example, cutting away a portion of a rectangular housing, and a portion of housing 210 may function as first and second reflecting members 211L and 211R or first and second reflecting members 212L and 212R. Alternatively, a concave housing 210 may be formed, and the side surfaces of a recess that is a portion of housing 210 may function as first and second reflecting members 212L and 212R. Alternatively, a modification of Fig. 21 may be made such that a concave housing 210 is formed, and the side surfaces of a recess that is a part of housing 210 function as first and second reflecting members 212L and 212R.

[0150] In the ninth embodiment, an example of the combined unit 300 has been described, but it is also possible to implement the ninth embodiment by replacing the housing 210 in the combined unit 300 with the vehicle body 190 in the autonomous mobile device 100. This makes it possible to provide an autonomous mobile device 100 that achieves the same effects as the combined unit 300 described above. The ninth embodiment can be implemented in combination with one or more other embodiments.

[0151] Tenth Embodiment In the tenth embodiment, other modifications of the number and arrangement of microphones and speakers provided in the autonomous mobile device 100 will be described with reference to Figures 23A to 23E. Figures 6A to 6C show examples of a configuration with one speaker and two microphones, and Figures 7A to 7D show examples of a configuration with two speakers and two microphones. In the tenth embodiment, examples in which the number of microphones is three or four will be described.

[0152] As shown in FIG. 23A , the autonomous mobile device 100 may further include a third microphone 51M attached to the vehicle body 190, which receives sound waves reflected by an object and converts the sound waves into an electrical signal. The first speaker 41 and the first to third microphones 51L, 51R, and 51M are arranged symmetrically with respect to a single target plane C1. The third microphone 51M is attached to the front end F1 of the vehicle body 190, at the center of the vehicle body 190 in the left-right direction, and facing an area including the front. The single target plane C1 is, for example, a central plane C1 that is parallel to a plane (XZ plane) including the front-rear and up-down directions of the autonomous mobile device 100 and includes the center of the vehicle body 190 in the left-right direction. The positions and orientations of the first speaker 41 and the first to third microphones 51L, 51R, and 51M are symmetrical with respect to the central plane C1. The first speaker 41 and the third microphone 51M are located in the same position and face the same forward direction. In this case, the first speaker 41 and the third microphone 51M can be configured as one module (a sensor for both transmission and reception).

[0153] As shown in Figures 23B to 23E, the autonomous mobile device 100 may include first through fourth microphones 51L1, 51L2, 51R1, and 51R2 attached to the vehicle body 190. The microphones 51L1, 51L2, 51R1, and 51R2 and the first speaker 41 are symmetrical with respect to a single symmetric plane, the central plane C1. The first through fourth microphones 51L1, 51L2, 51R1, and 51R2 may be attached to the front end F1 of the vehicle body 190, facing forward (Figure 23C). Two microphones 51L1 and 51R1 may be attached facing outward from the vehicle body 190 in the left-right direction, and the other two microphones 51L2 and 51R2 may be attached facing diagonally forward or forward (Figures 23D and 23E).

[0154] 23A to 23E, even if the number of speakers or microphones attached to the vehicle body 190 increases, all of the speakers and microphones are attached symmetrically with respect to a single target plane C1. This makes it possible to suppress deviations between the left and right sound pressures of the sound waves received by the first to fourth microphones 51L1, 51L2, 51R1, and 51R2.

[0155] The above-described embodiment is merely an example of the present invention, and therefore the present invention is not limited to the above-described embodiment, and various modifications can be made to the design and other aspects of the present invention without departing from the technical concept of the present invention.

[0156] Sound waves entering through openings in the vehicle body 190 or the housing 210 may be reflected inside the vehicle body 190 or the housing 210 and received as echo signals (noise) by the first and second microphones 51L and 51R. Therefore, as shown in FIG. 12 or FIG. 17A , for example, the housings 210, 220L, and 220R may be formed with only openings for the first and second microphones 51L and 51R to receive sound waves and an opening for outputting sound waves from the first microphone 41. This reduces the number of openings that allow sound waves to enter the housing 210, thereby reducing the sound waves that enter the housing 210. Also, FIG. 12 shows an example in which the first microphone 41 is disposed outside the housing 210, i.e., inside the outer edge of the housing 210, and therefore an opening for outputting sound waves is formed in the housing 210. However, this is not limiting, and the entire first microphone 41 may be disposed on the outer periphery of the housing 210, i.e., inside the outer edge of the housing 210. This eliminates the need for an opening for the first microphone 41, further reducing the number of openings that allow sound waves to enter the housing 210. Furthermore, if there is a gap between the outer periphery of the first and second microphones 51L and 51R and the inner periphery of the opening, sound waves can enter through the gap, causing increased noise. Therefore, as shown in FIG. 22B , the composite unit 300 may further include a microphone mounting board 215L on which the first microphone 51L is mounted, and a sealing member 216L made of rubber packing or the like that seals the gap between the housing 210 and the microphone mounting board 215L. The sealing member 216L is positioned to surround the periphery of the first microphone 51L, including the left-right and up-down directions of the first microphone 51L. This configuration seals the gap between the outer periphery of the first and second microphones 51L and 51R and the inner periphery of the opening, thereby reducing noise that enters through the gap. The gap may be reduced or closed by reducing or eliminating the difference between the outer diameter of the first and second microphones 51L, 51R and the inner diameter of the opening. It goes without saying that the autonomous mobile device 100 can be implemented by replacing the housing 210 with the vehicle body 190.

[0157] (Supplementary Notes) (Supplementary Note 1: First embodiment; Figures 6A to 8: Increasing left-right sound pressure difference) The autonomous mobile device 100 has a vehicle body 190, a first speaker 41 attached to the vehicle body 190 and transmitting sound waves toward an area including the front of the vehicle body 190, and a first microphone 51L and a second microphone 51R attached to the vehicle body 190 and receiving sound waves reflected by an object and converting the sound waves into electrical signals. The first speaker 41 and the first and second microphones 51L, 51R are located outside or on the outer periphery of the vehicle body 190 when viewed vertically. The first speaker 41 is located between the first and second microphones 51L, 51R in the left-right direction perpendicular to the front. The left-right distances from the center of gravity of the first speaker 41 or multiple speakers including the first speaker 41 to each of the first and second microphones 51L, 51R are equal.

[0158] (Supplementary Note 2: Second Embodiment; FIGS. 7E to 7H: Increasing Sound Pressure in the Front) In the autonomous mobile device 100 described in Supplementary Note 1, the first speaker 41 is disposed at the front end F1 of the vehicle body 190.

[0159] (Appendix 3: Second embodiment, Figures 7E to 7H: Contact detection sensor) The autonomous mobile device 100 described in Appendix 2 further has a contact detection sensor 214 that detects contact with an object, and is arranged forward of the first speaker 41 or at the same position as the first speaker 41 in the fore-and-aft direction.

[0160] (Appendix 4: Third embodiment, Figures 9 to 12: Reduction of rear noise) In the autonomous mobile device 100 described in any of Appendices 1 to 3, the vehicle body 190 has sound pressure reduction units 210aL, 210aR arranged behind the first and second microphones 51L, 51R, which reduce the sound pressure of the transmitted sound waves.

[0161] (Supplementary Note 5: Fourth embodiment; Figures 13 to 14B: Increasing diagonally forward sound pressure) The autonomous mobile device 100 described in any of Supplementary Notes 1 to 4 further includes a first reflecting member 211L that reflects sound waves, at least a portion of which is disposed behind the first microphone 51L, and a second reflecting member 211R that reflects sound waves, at least a portion of which is disposed behind the second microphone 51R. The first and second microphones 51L, 51R face in the left-right direction and toward the outside of the vehicle body 190, and the reflecting surfaces of the first and second reflecting members 211L, 211R face forward.

[0162] (Supplementary Note 6: Fourth embodiment; Figures 15A to 15B: Increasing diagonally forward sound pressure) The autonomous mobile device 100 described in any of Supplementary Notes 1 to 4 further includes a first reflecting member 212L that reflects sound waves, at least a portion of which is arranged inside the vehicle body 190 in the left-right direction of the first microphone 51L, and a second reflecting member 212R that reflects sound waves, at least a portion of which is arranged inside the vehicle body 190 in the left-right direction of the second microphone 51R. The first and second microphones 51L, 51R face forward, and the reflecting surfaces of the first and second reflecting members 212L, 212R face outward in the left-right direction.

[0163] (Appendix 7: Fourth embodiment, Figures 16 to 17B: Increasing diagonally forward sound pressure) In the autonomous mobile device 100 described in any of Appendices 1 to 4, the orientation of the first and second microphones 51L, 51R is tilted outward from the vehicle body 190 in the left-right direction rather than forward.

[0164] (Appendix 8: Fifth embodiment, Figures 18A to 18C: Reduction of sound pressure from opposite left and right sides) In the autonomous mobile device 100 described in any of Appendices 1 to 7, the car body 190 has a first sound pressure reduction unit 210bL that reduces the sound pressure of transmitted sound waves and is located outside the car body 190 of a first line segment connecting the first speaker 41 and the first microphone 51L when viewed from the vertical direction, and a second sound pressure reduction unit 210bR that reduces the sound pressure of transmitted sound waves and is located outside the car body 190 of a second line segment connecting the first speaker 41 and the second microphone 51R when viewed from the vertical direction.

[0165] (Appendix 9: Sixth embodiment, Figure 19: Reduction of sound pressure reflected by ground unevenness) The autonomous mobile device 100 described in any of Appendices 1 to 8 further has a protruding member 213 that protrudes from the bottom of at least one of the first speaker 41, the first microphone 51L, and the second microphone 51R in the direction of travel of the sound waves, and reduces the sound pressure of the transmitted sound waves.

[0166] (Appendix 10: Seventh embodiment, Figure 20: Increasing lateral sound pressure) In the autonomous mobile device 100 described in Appendix 5, the entire first reflecting member 211L is positioned behind the first microphone 51L, and the entire second reflecting member 211R is positioned behind the second microphone 51R.

[0167] (Appendix 11: Eighth embodiment, Figure 21: Increasing sound pressure in front) In the autonomous mobile device 100 described in Appendix 6, the entire first reflecting member 212L is positioned inside the vehicle body 190 to the left and right of the first microphone 51L, and the entire second reflecting member 212R is positioned inside the vehicle body 190 to the left and right of the second microphone 51R.

[0168] (Appendix 12: Ninth embodiment, Figures 22A to 22B: Increasing sound pressure to the sides and forward / lateral directions) In the autonomous mobile device 100 described in Appendix 7, the portions that receive sound waves from the first and second microphones 51L, 51R are visible from at least one of the front and left / right directions outside the vehicle body 190.

[0169] (Appendix 13: Ninth embodiment, Figure 22B: Increasing lateral and forward / lateral sound pressure) The autonomous mobile device 100 described in Appendix 12 further has a first reflecting member 211L arranged around the first microphone 51L to reflect sound waves toward the portion of the first microphone 51L that receives the sound waves, and a second reflecting member 211R arranged around the second microphone 51R to reflect sound waves toward the portion of the second microphone 51R that receives the sound waves.

[0170] (Supplementary Note 14: Tenth embodiment, FIGS. 23A to 23E) The autonomous mobile device 100 described in any of Supplementary Notes 1 to 13 further includes a second speaker 41R attached to the vehicle body 190 and transmitting sound waves forward, and a third microphone 51M attached to the vehicle body 190 and receiving sound waves reflected by an object and converting the sound waves into an electrical signal. The first and second speakers 41L, 41R and the first to third microphones 51L, 51R, 51M are arranged symmetrically with respect to a single target plane C1.

[0171] (Appendix 15: Structure for sealing gaps) The autonomous mobile device 100 described in any of Appendices 1 to 14 further includes a first microphone mounting board 215L on which the first microphone 51L is mounted, a first sealing member 216L that seals the gap between the vehicle body 190 and the first microphone mounting board 215L, a second microphone mounting board on which the second microphone 51R is mounted, and a second sealing member that seals the gap between the vehicle body 190 and the second microphone mounting board.

[0172] (Supplementary Note 16: Composite Unit Used in Autonomous Mobile Device) The composite unit 300 used in the autonomous mobile device 100 includes a housing 210, a first speaker 41 attached to the housing 210 and transmitting sound waves toward an area including the front of the housing 210, and a first microphone 51L and a second microphone 51R attached to the housing 210 and receiving sound waves reflected by an object and converting the sound waves into electrical signals. The first speaker 41 and the first and second microphones 51L, 51R are located outside or on the outer periphery of the housing 210 when the composite unit 300 is viewed vertically. The first speaker 41 is located between the first and second microphones 51L, 51R in the left-right direction perpendicular to the front. The left-right distances from the center of gravity of the first speaker 41 or multiple speakers including the first speaker 41 to each of the first and second microphones 51L, 51R are equal.

[0173] (Supplementary Note 17: Composite Unit Used in Autonomous Mobile Device) The autonomous mobile device 100 includes the composite unit 300 described in Supplementary Note 16.

[0174] (Supplementary Note 18) The autonomous mobile device 100 described in Supplementary Note 17 further has a structure surrounding the bottom and top surfaces of the combination unit 300. This structure can reduce the sound pressure of sound waves that arrive from behind the autonomous mobile device 100, go around the bottom and top surfaces of the combination unit 300, and enter the first and second microphones 51L, 51R.

[0175] (Appendix 19: Digital pheromones + echolocation) The autonomous mobile device 100 moves autonomously using radio waves and sound waves. The autonomous mobile device 100 has a receiving unit 110 that receives radio waves, an angle estimation unit 134 that estimates the direction of arrival of the radio waves, a first speaker 41 that transmits sound waves in a straight direction in which the autonomous mobile device 100 is moving, a first microphone 51L and a second microphone 51R that receive sound waves reflected by an object and convert them into first and second audio signals, respectively, and an operation control unit 135 that controls the direction of movement of the autonomous mobile device 100 based on the first audio signal, the second audio signal, and the direction of arrival of the radio waves.

[0176] (Supplementary Note 20) In the autonomous mobile device 100 described in Supplementary Note 18, the operation control unit 135 controls the direction of movement of the autonomous mobile device 100 based on the echo signals contained in the first audio signal and the second audio signal and the direction of arrival of the radio waves.

[0177] The entire contents of Japanese Patent Application No. 2022-181345 (filing date: November 11, 2022) are incorporated herein by reference and are protected from mistranslations and omissions.

[0178] 41, 41L First speaker, 41R Second speaker, 51L, 51L1 First microphone, 51M Third microphone, 51R, 51R1 Second microphone, 60A, 60B Object, 100 Autonomous mobile device, 190 Vehicle body, 214 Contact detection sensor, 210 Housing, 210aL, 210aR Sound pressure reduction unit, 210bL First sound pressure reduction unit, 210bR Second sound pressure reduction unit, 211L, 212L First reflecting member, 211R, 212R Second reflecting member, 213 Protruding member, 300 Composite unit, C1 Single target surface, F1 Front end of vehicle body, F2 Front end of housing

Claims

1. A vehicle body, a first speaker attached to the vehicle body and transmitting sound waves toward an area including the front of the vehicle body, a first microphone and a second microphone attached to the vehicle body, receiving the sound waves reflected by an object, and converting the sound waves into electrical signals, wherein the first speaker and the first and second microphones are located outside or on the outer periphery of the vehicle body when viewed from the vertical direction, the first speaker is located between the first and second microphones in the left-right direction perpendicular to the front, the distances in the left-right direction from the center of gravity of the first speaker or a plurality of speakers including the first speaker to each of the first and second microphones are equal, an autonomous mobile device.

2. The autonomous mobile device according to claim 1, wherein the first speaker is disposed at the front end of the vehicle body.

3. The autonomous mobile device according to claim 2, further comprising a contact detection sensor that is disposed in front of the first speaker or at the same position as the first speaker in the front-rear direction and detects contact with an object.

4. The autonomous mobile device according to claim 1, wherein the vehicle body has a sound pressure reduction portion disposed behind the first and second microphones and reducing the sound pressure of the transmitted sound waves.

5. a first reflecting member that reflects the sound waves and at least a part of which is disposed behind the first microphone, a second reflecting member that reflects the sound waves and at least a part of which is disposed behind the second microphone, wherein the first and second microphones face the outside of the vehicle body in the left-right direction, the reflecting surfaces of the first and second reflecting members face the front, the autonomous mobile device according to any one of claims 1 to 4.

6. a first reflecting member that reflects the sound waves and at least a part of which is disposed inside the vehicle body in the left-right direction of the first microphone, a second reflecting member that reflects the sound waves and at least a part of which is disposed inside the vehicle body in the left-right direction of the second microphone, wherein the first and second microphones face the front, the reflecting surfaces of the first and second reflecting members face the outside in the left-right direction, the autonomous mobile device according to any one of claims 1 to 4.

7. The autonomous mobile device according to any one of claims 1 to 4, wherein the directions of the first and second microphones are inclined more toward the outside of the vehicle body in the left-right direction than the front.

8. The vehicle body, A first sound pressure reduction unit that reduces the sound pressure of the transmitted sound wave and is located outside the vehicle body with respect to a first line segment connecting the first speaker and the first microphone when viewed from the vertical direction. A second sound pressure reduction unit that reduces the sound pressure of the transmitted sound wave and is located outside the vehicle body with respect to a second line segment connecting the first speaker and the second microphone when viewed from the vertical direction. The autonomous mobile device according to any one of claims 1 to 4.

9. The autonomous mobile device according to any one of claims 1 to 4, further comprising a protruding member that protrudes in the traveling direction of the sound wave from at least one of the lower parts of the first speaker, the first microphone, and the second microphone and reduces the sound pressure of the transmitted sound wave.

10. The entire first reflecting member is disposed behind the first microphone. The entire second reflecting member is disposed behind the second microphone. The autonomous mobile device according to claim 5.

11. The entire first reflecting member is disposed inside the vehicle body in the left - right direction of the first microphone. The entire second reflecting member is disposed inside the vehicle body in the left - right direction of the second microphone. The autonomous mobile device according to claim 6.

12. For the autonomous mobile device according to claim 7, the portions of the first and second microphones that receive the sound wave are visible from at least one of the front and the outside of the vehicle body in the left - right direction.

13. A first reflecting member disposed around the first microphone and reflecting the sound wave toward the portion of the first microphone that receives the sound wave. And a second reflecting member disposed around the second microphone and reflecting the sound wave toward the portion of the second microphone that receives the sound wave. The autonomous mobile device according to claim 12.

14. A second speaker attached to the vehicle body and transmitting the sound wave forward. A third microphone attached to the vehicle body, receiving the sound wave reflected by an object, and converting the sound wave into an electrical signal. The first and second speakers and the first to third microphones are arranged facing a single target surface. The autonomous mobile device according to any one of claims 1 to 4.

15. A first microphone mounting board on which the first microphone is mounted. A first sealing member that fills a gap between the vehicle body and the first microphone mounting board. A second microphone mounting board on which the second microphone is mounted. A second sealing member that fills the gap between the vehicle body and the second microphone mounting substrate; further comprising The autonomous mobile device according to any one of claims 1 to 4.

16. A composite unit used in an autonomous mobile device, comprising: a housing; a first speaker attached to the housing and transmitting sound waves toward a region including the front of the housing; a first microphone and a second microphone attached to the housing, receiving the sound waves reflected by an object, and converting the sound waves into electrical signals; the first speaker and the first and second microphones are located outside or on the outer periphery of the housing when viewed from the vertical direction; the first speaker is located between the first and second microphones in the left-right direction perpendicular to the front; the distances in the left-right direction from the center of gravity of the first speaker or a plurality of speakers including the first speaker to each of the first and second microphones are equal; A composite unit of a speaker and a microphone for an autonomous mobile device.

17. An autonomous mobile device having the composite unit according to claim 16.