Mobile body

Abstract

Provided is a mobile body comprising a sensor and a load-carrying platform, in which the loading capacity of the load-carrying platform is ensured and a sensor detection range is also ensured.　A mobile body 1 comprises: a carriage 10 capable of autonomous movement; a load-carrying platform 20 provided on an upper side of the carriage 10 separated by a prescribed interval; a support body 19 provided between the carriage 10 and the load-carrying platform 20 and fixing the load-carrying platform 20 to the carriage 10; and two distance-measuring sensors 30A, 30B provided between the carriage 10 and the load-carrying platform 20.　In the mobile body 1, the two distance-measuring sensors 30A, 30B are arranged with the support body 19 interposed therebetween.

Description

Mobile

[0001] The present invention relates to a moving body capable of transporting an article.

[0002] Conventionally, so-called autonomous mobile objects that travel autonomously to transport goods are known. These mobile objects are equipped with sensors that measure the distance to objects in order to detect the surrounding environment, and the mobile objects identify their own positions by comparing the acquired information about the surrounding environment with pre-stored map information.

[0003] A sensor that measures the distance to an object measures the distance based on the time it takes for the laser light to be emitted, reflected from the object, and returned. Various factors, such as the shape and surface material of the object, can cause errors in the distance measurement or produce anomalous values ​​that deviate significantly from the ideal value. Patent Document 1 therefore provides a mobile object that can accurately calibrate the sensor's misalignment relative to the cart.

[0004] Japanese Patent Application Laid-Open No. 2021-9634

[0005] A mobile object that transports an object may have a loading platform on which the object is mounted. In a mobile object that has a loading platform, if a sensor is provided on the loading platform, the loading capacity of the loading platform will be reduced by the amount of space occupied by the sensor. Note that Patent Document 1 does not have a loading platform.

[0006] SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to ensure the load capacity of the loading platform while ensuring the detection range of the sensor in a mobile body equipped with a sensor and a loading platform.

[0007] The mobile body of the present invention comprises an autonomously movable carriage, a loading platform provided above the carriage at a predetermined distance, a support provided between the carriage and the loading platform for fixing the loading platform to the carriage, and two distance measuring sensors provided between the carriage and the loading platform. In the mobile body of the present invention, at least two distance measuring sensors are arranged with the support sandwiched between them.

[0008] In the moving body of the present invention, the two sensors are preferably arranged at symmetrical positions with respect to the support body.

[0009] In the moving body of the present invention, it is preferable that the support body has a rectangular, particularly square, outer shape in a plan view, one diagonal of the rectangle facing the front-to-rear direction of the moving body, and in this case, the two sensors are arranged on an extension of one diagonal.

[0010] According to the present invention, the distance measurement sensor is provided between the cart and the loading platform, so the area on the loading platform for placing an object is not reduced even if the distance measurement sensor is provided. Furthermore, according to the present invention, the two distance measurement sensors are disposed with the support between them, so that the reduction in the detection range of each distance measurement sensor due to the presence of the support can be minimized.

[0011] FIG. 1 is a diagram showing a moving body according to an embodiment, showing a state with a loading platform and a state with the loading platform removed; FIG. 2 is a diagram showing a moving body according to an embodiment, showing a field of view of a distance measurement sensor; FIG. 3 is a diagram showing a moving body according to an embodiment, showing an example in which other devices are provided above the loading platform; FIG. 4 is a diagram showing an example of distance measurement by a moving body according to an embodiment; FIG. 5 is a diagram showing another example of distance measurement by a moving body according to an embodiment.

[0012] A mobile body 1 according to an embodiment of the present invention will be described below with reference to the accompanying drawings. The mobile body 1 includes a dolly 10, a loading platform 20 provided above the dolly 10 at a predetermined distance, and two LiDARs 30A and 30B as distance measuring sensors provided between the dolly 10 and the loading platform 20. The loading platform 20 is fixed to and supported by a support 19 provided integrally with the dolly 10, for example, and the LiDARs 30A and 30B are disposed with the support 19 sandwiched between them. Note that LiDAR is an abbreviation for Light Detection and Ranging, a technology that irradiates laser light and measures the distance to an object, the shape of the object, and the like based on information on the reflected light.

[0013] In the mobile body 1, the LiDARs 30A and 30B are provided between the cart 10 and the loading platform 20, so the mounting surface 21 of the loading platform 20 is not restricted by the LiDARs 30A and 30B, and therefore there is no reduction in the loading capacity of the loading platform 20. Furthermore, in the mobile body 1, the two LiDARs 30A and 30B are arranged with the support body 19 sandwiched between them, so that the reduction in the detection range of each of the LiDARs 30A and 30B due to the presence of the support body 19 can be minimized.

[0014] [Carriage 10: See Figures 1 and 2] The carriage 10 is responsible for the autonomous driving of the moving body 1. The carriage 10 includes a vehicle body 11 and, as an example, wheels 17A, 17B, and 17C provided below the vehicle body 11, and realizes movement such as forward movement, backward movement, and turning. The carriage 10 includes drive sources for the wheels 17A, 17B, and 17C, a controller that controls the operation of the drive sources in accordance with the results of distance measurement by the LiDARs 30A and 30B, and the like. However, since known configurations can be adopted for these movement mechanisms, detailed description thereof will be omitted. The number of wheels is not limited to three, and may be four or more.

[0015] The vehicle body 11 has a rectangular parallelepiped appearance, and its top surface, the top plate 13, is rectangular in plan view. As shown in Figure 1, the vehicle body 11 is defined as having a front (F), a rear (R), a longitudinal direction (L), a width direction (W), and a height direction (H).

[0016] A support body 19 is integrally provided at approximately the center of the top plate 13 in the longitudinal direction (L) and width direction (W). The support body 19 protrudes from the top plate 13 in the height direction (H) and has, for example, a rectangular outer shape in a plan view. One of two diagonals D1, D2 of the support body 19 (diagonal line D1) extends in the longitudinal direction (L), and the other (diagonal line D2) extends in the width direction (W). As an example, the diagonal line D1 bisects the top plate 13 in the width direction (W), and the diagonal line D2 bisects the top plate 13 in the longitudinal direction (L). Note that, while an example is shown in which the support body 19 is formed integrally with the top plate 13, i.e., the vehicle body 11, the support body 19 may be manufactured separately from the vehicle body 11 and fixed to the top plate 13, or may be formed integrally with the loading platform 20.

[0017] [Loading platform 20: see FIGS. 1 and 2] The loading platform 20 has a loading surface 21 on its upper surface, and an article (not shown) to be transported by the mobile body 1 is placed on this loading surface 21. As an example, the loading surface 21 has a rectangular planar shape similar to the top plate 13, and has a planar area approximately equal to that of the top plate 13. However, this planar shape and planar area are merely examples. Other planar shapes, such as a polygon such as a triangle or an oval, may be selected according to the shape and dimensions of the article to be transported, and a planar area larger or smaller than that of the top plate 13 may also be selected.

[0018] Because the loading platform 20 is supported and fixed to the support body 19, a predetermined gap G is provided between the loading platform 20 and the top plate 13, excluding the area of ​​the support body 19, and the LiDARs 30A and 30B are disposed in this gap G. In other words, the LiDARs 30A and 30B are disposed inside the periphery of the vehicle body 11 and loading platform 20, and will not receive a direct impact even if the trolley 10 collides with some object.

[0019] [LiDAR 30A, 30B: see Figures 1 and 2] The two LiDARs 30A, 30B are examples of sensors that measure the distance to objects present around the moving body 1. Note that similar devices can be applied to the LiDAR 30A and the LiDAR 30B, and therefore, unless there is a particular need to distinguish between them in the following description, the two laser scanners will also be collectively referred to as "LiDAR 30."

[0020] The LiDAR 30, for example, emits laser light parallel to the main surface of the cart 10, and measures distance based on the time it takes for the light to be reflected by the object and return. The LiDAR 30 has a measurement range of, for example, a predetermined radius (for example, about 10 m), and acquires measurement values ​​of several hundred to several thousand points per scan while scanning the laser light over a predetermined field of view (for example, about 360 degrees) at a predetermined degree pitch (for example, about 0.2 to 0.5 degrees).

[0021] The two LiDARs 30A, 30B are located on an extension of the longitudinal direction (L) of the diagonal line D1 of the support 19 of the cart 10, at the front (F) and rear (R) of the support 19, respectively. In other words, the two LiDARs 30A, 30B are positioned symmetrically with respect to the support 19. This allows the fields of view FV1, FV2 of the two LiDARs 30A, 30B to be equal. Combining the data acquired from the two LiDARs 30A, 30B enables distance measurement in a wide range of directions as seen from the cart 10. By measuring the surrounding environment using the LiDAR 30, the mobile body 1 can create an environmental map of the surrounding environment and compare it with pre-stored map information to estimate the mobile body 1's own position, plan a route, and avoid obstacles, enabling autonomous movement to a destination. In FIG. 2, FV1 indicates the range in which distance measurement is possible by LiDAR 30A, and FV2 indicates the field of view range in which distance measurement is possible by LiDAR 30B.

[0022] The LiDAR 30 is an example of a sensor that senses the surrounding environment of the transport vehicle. Such a sensor is not limited to a laser scanner, and may be any sensor that can measure the distance to an object, such as an ultrasonic sensor, a distance sensor using microwaves, or a distance sensor using stereo images captured by a stereo camera.

[0023] In addition, in this embodiment, the moving body 1 is equipped with two LiDARs 30A and 30B, but the number of sensors equipped on the transport vehicle may be three or more.

[0024] [Effects of the Mobile Body 1] <First Effect: Ensuring Mounting Area on the Loading Platform 20> In the mobile body 1, the LiDARs 30A and 30B are disposed in the gap G between the top plate 13 of the vehicle body 11 and the loading platform 20, so providing the LiDARs 30A and 30B does not reduce the mounting area of ​​the transported object on the loading platform 20. Therefore, with the mobile body 1, the planar area of ​​the loading platform 20 can be fully secured as the mounting area. Furthermore, there is no need to secure space above the loading platform 20 for sensing by the LiDARs 30A and 30B, and other equipment 40 required for the autonomous driving of the mobile body 1 can be provided above the loading platform 20.

[0025] <Second Effect: Sensing Range of LiDARs 30A and 30B: See FIG. 2> The sensing range of a moving body 1 in which the support 19 is concentrated inside the sensor fields of view of the LiDARs 30A and 30B will be described. This sensing range is the range in the horizontal direction. Due to the presence of the support 19, the sensing range of each of the LiDARs 30A and 30B is restricted. The LiDAR 30A disposed in the front (F) has a blind spot in the 90-degree range around the corner in front (F) of the support 19, but can sense a field of view FV1 of 270 degrees excluding this range. The LiDAR 30A disposed in the rear (R) has a blind spot in the 90-degree range around the corner behind (R) the support 19, but can sense a field of view FV2 of 270 degrees excluding this range. In other words, LiDAR 30A, 30B enable sensing in a 360° range outside the vehicle body 11, improving safety and control stability during autonomous driving of the mobile body 1. Note that the 90° blind spot and 270° field of view are merely examples, and the blind spot and field of view may be at other angles depending on the dimensions of the vehicle body 11, etc.

[0026] <Third Effect: Sensing of Objects at Close Distance; See FIGS. 4 and 5> By providing two LiDARs 30A and 30B, the mobile body 1 can reduce the influence of blind spots (occlusions) caused by obstacles when measuring the shape of an object (measurement target) at close range. For example, as shown in FIG. 4, each of the LiDARs 30A and 30B can simultaneously measure both the front surface 101A and the back surface 101B of the measurement target 101. Furthermore, as shown in FIG. 5, while the LiDAR 30A is measuring the measurement target 102, the LiDAR 30B can scan the blind spot behind the measurement target 102 as seen from the LiDAR 30A.

[0027] <Fourth Effect: Ensuring Safety of LiDAR 30A, 30B> The LiDAR 30A, 30B are installed between the vehicle body 11 and the loading platform 20, close to the inside of the vehicle body. Therefore, according to the mobile body 1, even if the vehicle body 11 collides with a surrounding object, the LiDAR 30A, 30B are only indirectly impacted, making them less likely to be damaged. Furthermore, even if the mobile body 1 autonomously travels in the rain, the LiDAR 30A, 30B are less likely to be covered in rain. In addition, LiDAR has a minimum measurable distance at which it is unable to measure distance if the distance to the measurement target is too close. The LiDAR 30A, 30B are installed inside the periphery of the vehicle body 11 and the loading platform 20, making it possible to reduce the influence of the LiDAR's minimum measurable distance when measuring distance to an object.

[0028] While preferred embodiments have been described above, the configurations described in the above embodiments may be selected or modified as appropriate without departing from the spirit and scope of the present invention. The rectangular support 19 described above has a diagonal line D1 extending in the longitudinal direction (L) and a diagonal line D2 extending in the width direction (W), but the present invention is not limited to this. The diagonal line D1 may be parallel to the longitudinal direction (L) and the diagonal line D2 may be parallel to the width direction (W). Furthermore, the support 19 is not limited to a rectangular shape and can have other shapes, such as a circle or a polygon. Furthermore, while an example has been described in which the two LiDARs 30A and 30B are arranged symmetrically with respect to the support 19, the present invention is not limited to this, and they may be arranged in asymmetric positions. Even in the above example, the first effect described above can be achieved.

[0029] 1 Mobile body 10 Cart 11 Body 13 Top plate 17A, 17B, 17C Wheels 19 Support 20 Platform 21 Mounting surface 30A, 30B LiDAR (ranging sensor) 40 Equipment D1, D2 Diagonal G Spacing FV1, FV2 Field of view

Claims

1. A moving body comprising: a cart capable of autonomous movement; a loading platform provided above the cart at a predetermined distance; a support provided between the cart and the loading platform for fixing the loading platform to the cart; and two distance measuring sensors provided between the cart and the loading platform, the two distance measuring sensors being positioned with the support in between.

2. The moving body according to claim 1, wherein the two distance measuring sensors are arranged at symmetrical positions with respect to the support body.

3. A moving body as described in claim 1 or claim 2, wherein the support body has a rectangular outer shape in a planar view, one diagonal of the rectangle faces in the fore-and-aft direction of the moving body, and the two distance measuring sensors are positioned on an extension of one of the diagonals.

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