JP2024177714A - Transfer robot - Google Patents

Abstract

To secure extendability while restraining introduction cost from increasing in a transfer robot which transports a transfer object by submerging under the transfer object.SOLUTION: A transfer robot is provided with a travel part capable of traveling to a plurality of directions which contains a first direction at plan view. In addition, the transfer robot comprises a pair of gripping arms for gripping a transfer object and a pair of guiding devices which guide the pair of gripping arms along a second direction perpendicularly intersecting at the first direction at plan view in a straight line. Furthermore, the transfer robot comprises a drive part which allows the pair of gripping arms to approach and separate from each other along the second direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to a transport robot.

In recent years, transport robots such as AGVs (Automatic Guided Vehicles) and AMRs (Autonomous Mobile Robots) have become widespread. Patent Document 1 discloses a transport robot having a vehicle body provided with a traveling device and a lifter. This transport robot transports an object to be transported, such as a dolly, by getting under the object, lifting the object with the lifter, and traveling with the traveling device.

Patent document 2 discloses a transport robot having a vehicle body equipped with extendable movable pins and a traveling device. This transport robot transports the object by getting under the object, engaging the movable pins with special grooves provided in the object, and traveling on the traveling device.

JP 2019-059460 A JP 2022-149833 A

However, the transport robot described in Patent Document 1 requires a high-torque lifter to lift the object to be transported, and therefore the object may need to be reinforced accordingly. In addition, the transport robot described in Patent Document 2 requires the object to be provided with a special groove that engages with the movable pin. Therefore, when introducing transport robots such as those described in Patent Documents 1 and 2, the object to be transported needs to be processed, which may increase costs and reduce the versatility of the transport robot.

In addition, in order to transport the object safely, it is also important to attach a sensor for detecting obstacles and a shock absorber (e.g., a bumper, etc.) for mitigating the impact when coming into contact with an obstacle. However, in a transport robot that can get under the object to be transported, if a sensor is attached to the vehicle body, the detection range of the sensor may be limited by the casters of the object to be transported. In response to this, a method of attaching the sensor so that it protrudes from the object to be transported in a plan view can be considered, but this may result in an increase in the size of the transport robot when the object is not being transported. In addition, the shock absorber needs to be attached to the transport robot so that it protrudes from the object to be transported in a plan view, which may result in an increase in the size of the transport robot when the object is not being transported. Therefore, it is desirable to have the scalability to attach sensors, shock absorbers, etc. to the transport robot without increasing the size of the transport robot.

The present invention was made in consideration of the various circumstances described above, and its purpose is to ensure scalability while suppressing increases in implementation costs in a transport robot that crawls under an object to transport it.

One aspect of the present invention is a transport robot that transports an object by slipping at least a part of its body under the object. In this case, the transport robot may, for example,
A traveling unit attached to the vehicle body and capable of traveling in a plurality of directions including a first direction in a plan view;
A pair of gripping arms for gripping the transport object;
a pair of guide devices attached to the vehicle body and configured to linearly guide the pair of gripping arms along a second direction perpendicular to the first direction in a plan view;
a drive unit that moves the pair of gripping arms toward and away from each other along the second direction;
Equipped with.

According to the present invention, a transport robot that crawls under an object to transport it can ensure scalability while suppressing increases in implementation costs.

1 is a perspective view showing a schematic configuration of a transport robot according to an embodiment. FIG. 2 is a top view showing a schematic configuration of the transport robot according to the embodiment. FIG. 4 is a top view showing an example of the shape and arrangement of a pair of gripping arms in the embodiment. FIG. 4 is a side view focusing on the attachment portion of the pair of gripping arms to the vehicle body in the embodiment. FIG. 2 is a cross-sectional view showing an example of a configuration of an actuator in the embodiment. FIG. 2 is a perspective view of the transport robot in a state where a pair of gripping arms are spaced apart from each other in the embodiment. FIG. 2 is a top view of the transport robot in a state where a pair of gripping arms are spaced apart from each other in the embodiment. 11A to 11C are diagrams illustrating an example of the operation of the transport robot when transporting a transport target in the embodiment. 1 is a perspective view of a transport robot in an embodiment in which a transport target is gripped by a pair of gripping arms. 1 is a side view of a transport robot in an embodiment in which a transport target is gripped by a pair of gripping arms.

A transport robot, which is one aspect of the present invention, includes a travel unit capable of traveling in multiple directions including a first direction in a plan view. This allows the transport robot to move in multiple directions including the first direction in a plan view. The transport robot also includes a pair of gripping arms for gripping an object to be transported, and a pair of guiding devices for linearly guiding the pair of gripping arms along a second direction perpendicular to the first direction in a plan view. This allows the transport robot to be mounted with the pair of gripping arms in a state in which they can freely move toward and away from each other along the second direction. Furthermore, the transport robot includes a drive unit that moves the pair of gripping arms toward and away from each other along the second direction. This allows the transport robot to move the pair of gripping arms toward and away from each other along the second direction.

When the transport object is transported by the transport robot configured as described above, the traveling unit drives the transport robot to a position where the second direction and the width direction of the transport object are parallel (in other words, the first direction and the width direction of the transport object are perpendicular) and the transport object and the vehicle body face each other. In addition, the driving unit separates the pair of gripping arms so that the relative distance between the pair of gripping arms in the second direction is greater than the width of the transport object. At that time, the pair of gripping arms are linearly guided along the second direction by the pair of guide devices, so that they are separated from each other. Note that the movement of the transport robot and the separation of the pair of gripping arms may be performed first, or may be performed simultaneously. However, considering the mobility and safety of the transport robot when it is not transporting the transport object, it is desirable that the pair of gripping arms are separated after the movement of the transport robot is completed.

Next, the travel unit moves the transport robot along a first direction toward the transport target, thereby drawing the transport target between the pair of separated gripping arms. When the transport target is drawn between the pair of gripping arms, the drive unit moves the pair of gripping arms closer to each other. At that time, the pair of gripping arms move closer to each other by being linearly guided along a second direction by a pair of guiding devices. Then, when the relative distance between the pair of gripping arms becomes approximately equal to the width of the transport target, the transport target is gripped by the pair of gripping arms. When the transport target is gripped by the pair of gripping arms, the travel unit moves the transport robot toward the destination.

The transport robot according to the present invention can transport an object by gripping it with a pair of gripping arms. This allows the object to be transported without lifting it up or connecting it to the transport robot with a dedicated mechanism. In other words, it can transport objects that are not dedicated objects that have been reinforced, grooved, or otherwise processed. As a result, the versatility of the transport robot can be increased, and the cost of introducing the transport robot can be reduced accordingly.

In addition, with the transport robot according to the present invention, the pair of gripping arms can be kept close to each other when the transport object is not being transported, allowing the transport robot to be made smaller. This increases the mobility and safety of the transport robot when it travels alone, and also makes it easier to secure storage space for the transport robot.

In the transport robot according to the present invention, the pair of gripping arms may be formed in a substantially U-shape in plan view, and may be arranged so that the openings of the U-shape face each other. This makes it possible to grip a transport target that is rectangular in plan view. Furthermore, it is possible to prevent the transport target from slipping out of the gripping arms or the posture of the transport target from becoming unstable during transport. The shape of the pair of gripping arms is not limited to the above-mentioned shape, and may be changed according to the shape of the transport target. For example, if the transport target is circular in plan view, the gripping arms may be formed in a substantially arc-like shape in plan view, and may be arranged so that the openings of the arc face each other. This makes it possible to stably grip a transport target that is circular in plan view.

In a configuration in which the pair of gripping arms are formed in a substantially U-shape in plan view and are arranged so that the openings of the U-shape face each other, each gripping arm may include a first arm portion extending parallel to the second direction in plan view, a second arm portion extending parallel to the first direction from the tip of the first arm portion, and a third arm portion extending parallel to the first arm portion from the tip of the second arm portion, and the length of the third arm portion in the second direction may be formed to be shorter than the length of the first arm portion in the second direction. This makes it possible to keep the distance between the pair of gripping arms small when the transport target is called in between the pair of gripping arms. Therefore, even if the space around the transport target is relatively narrow, it is possible to call in and grip the transport target.

In addition, in a configuration in which a pair of gripping arms are formed in a substantially U-shape in plan view and are arranged so that the openings of the U-shape face each other, a pair of obstacle sensors may be arranged at positions diagonally opposite each other on the pair of gripping arms in plan view. In this case, a sensor capable of detecting obstacles present within a range of 270 degrees or more from the obstacle sensor itself may be used as each obstacle sensor. This makes it possible to minimize the number of obstacle sensors installed while suppressing the occurrence of blind spots. Therefore, it is possible to ensure scalability in the installation of obstacle sensors. Note that, for example, LiDAR (Light Detection And Ranging), a depth sensor, or a camera may be used as the obstacle sensor.

In addition, a pair of contact sensors that detect contact with an obstacle may be attached to the pair of gripping arms instead of or in addition to the obstacle sensors. In this case, the contact sensors are provided on the outer surfaces of the pair of gripping arms in a plan view. As a result, when the transport robot according to the present invention transports an object to be transported, the contact sensors are positioned outside the object to be transported in a plan view, so that it is possible to detect contact with an obstacle while preventing the object to be transported from contacting the obstacle. This ensures extensibility in terms of the attachment of the contact sensors.

In addition to or in place of the contact sensor described above, a shock absorber such as a bumper can be attached to the outer surface of the pair of gripping arms. When using a contact sensor and a shock absorber together, the contact sensor only needs to be attached to the outer surface of the shock absorber in a plan view. In this way, when the transport robot according to the present invention transports an object to be transported, the shock absorber is positioned outside the object to be transported in a plan view, making it possible to prevent the object from coming into contact with an obstacle and to reduce the impact when the object comes into contact with an obstacle.

A contact sensor may also be attached to the inner surfaces of the pair of gripping arms when viewed from above. This makes it possible for the drive unit to automatically stop the gripping operation of the pair of gripping arms when the contact sensor detects contact with the transport target during the gripping operation of the pair of gripping arms (operation of bringing the pair of gripping arms closer to each other).

In the transport robot according to the present invention, the drive unit may include a pair of screw shafts extending along a second direction, the pair of screw shafts having screw grooves that are in opposite directions, a pair of nuts attached to each of the pair of screw shafts, the pair of nuts being respectively connected to the pair of gripping arms, and an actuator that has a rotating shaft that connects the pair of screw shafts to each other and a cross roller bearing that rotatably supports the rotating shaft and rotates the rotating shaft. This allows the pair of gripping arms to approach and move away from each other with a single actuator. In addition, since the thrust load of the screw shafts can be applied by the cross roller bearing, it is possible to ensure the durability of the actuator while improving the rotation accuracy of the pair of screw shafts.

Each of the pair of gripping arms may be configured to have a variable length in the first direction. This allows the length of the pair of gripping arms in the first direction to be changed according to the depth of the transport object. As a result, the versatility of the transport robot can be further increased.

It is also possible to attach an operation panel equipped with a display device or a speaker to one of the pair of gripping arms. In this case, a screen or sound indicating the direction in which the transport robot is moving may be output from the display device or the speaker to people around the transport robot. This can also alert people around the transport robot while it is moving.

<Embodiment>
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative positions, and the like of the components described in the embodiment are not intended to limit the scope of the present invention.

(Schematic configuration of the transport robot)
In this embodiment, an example will be described in which a transport robot according to the present invention is applied to transporting a cart on which an object is loaded. Fig. 1 is a perspective view of the transport robot 1. Fig. 2 is a top view of the transport robot 1. As shown in Figs. 1 and 2, the transport robot 1 comprises a substantially rectangular parallelepiped body 10, four Mecanum wheels 11, and a pair of gripping arms 12A-12B.

In the following description, an XYZ Cartesian coordinate system is defined, and the arrangement of the components of the transport robot 1 is described with reference to this XYZ Cartesian coordinate system. In this embodiment, the longitudinal direction of the vehicle body 10 (the direction from the lower left to the upper right in FIG. 1) is defined as the X-axis direction (corresponding to the "second direction" of the present invention), the lateral direction of the vehicle body 10 (the direction from the lower right to the upper left in FIG. 1) is defined as the Y-axis direction (corresponding to the "first direction" of the present invention), and the direction perpendicular to the X-axis direction and the Y-axis direction (the vertical direction or height direction) is defined as the Z-axis direction.

The four Mecanum wheels 11 are attached to the vehicle body 10 so as to rotate around an axis parallel to the Y-axis direction. The four Mecanum wheels 11 are configured so that the rotation direction and rotation speed can be controlled independently of each other. This allows the four Mecanum wheels 11 to translate the transport robot 1 in multiple directions including the X-axis direction and the Y-axis direction. The four Mecanum wheels 11 can also rotate the transport robot 1, pivot, and super pivot. The four Mecanum wheels 11 configured in this way correspond to the "running unit" according to the present invention.

The configuration of the running unit is not limited to the above example, and may be any configuration that moves the transport robot 1 in parallel at least in the X-axis direction and the Y-axis direction. For example, the running unit of the transport robot 1 may be configured with a plurality of omniwheels. The running unit may also be configured in the same manner as a known AMR (Autonomous Mobile Robot) or AGV (Automatic Guided Vehicle).

The pair of gripping arms 12A-12B are attached to the vehicle body 10 so that they can move toward and away from each other along the X-axis direction. The pair of gripping arms 12A-12B are moved toward and away from each other by an actuator 14, which will be described later. Details of the pair of gripping arms 12A-12B and the actuator 14 will be described later.

In this embodiment, the transport robot 1, with the pair of gripping arms 12A-12B spaced apart from each other, sneaks under the cart 20 and calls the cart 20 between the pair of gripping arms 12A-12B. With the cart 20 called between the pair of gripping arms 12A-12B, the transport robot 1 brings the pair of gripping arms 12A-12B closer to each other to grip the cart 20. The transport robot 1 travels with the cart 20 gripped by the pair of gripping arms 12A-12B, thereby transporting the cart 20 to an arbitrary destination.

The transport robot 1 in this embodiment can transport the cart 20 without lifting up the cart 20 or connecting the cart 20 and the transport robot 1 with a dedicated mechanism. In other words, the transport robot 1 in this embodiment does not require any processing of the cart 20. This can increase the versatility of the transport robot 1, and accordingly, can suppress any increase in the introduction cost of the transport robot 1.

(Grabbing arm)
Here, the gripping arms 12A-12B mounted on the transfer robot 1 of this embodiment will be described with reference to Fig. 3. Fig. 3 is a top view showing an example of the shape and arrangement of the pair of gripping arms 12A-12B.

The pair of gripping arms 12A-12B are arranged to be symmetrical with respect to a virtual straight line parallel to the Y-axis direction in a plan view, as shown in Fig. 3. Hereinafter, of the pair of gripping arms 12A-12B, the gripping arm 12A arranged on the X-axis direction side (right side in Fig. 3) is referred to as the first gripping arm 12A, and the gripping arm 12A arranged on the opposite side to the X-axis direction (left side in Fig. 3) is referred to as the second gripping arm 12A.
2B is referred to as the second gripping arm 12B. However, when the first gripping arm 12A and the second gripping arm 12B are collectively referred to, they will be referred to as gripping arms 12A-12B.

The first gripping arm 12A includes a first arm portion 120A extending in the X-axis direction (to the right in FIG. 3), a second arm portion 121A extending in the Y-axis direction (upward in FIG. 3) from the tip end (end portion on the X-axis direction side) of the first arm portion 120A, and a third arm portion 122A extending in the opposite direction to the X-axis direction (to the left in FIG. 3) from the tip end (end portion on the Y-axis direction side) of the second arm portion 121A. That is, the first gripping arm 12A is configured to have a substantially U-shape in a plan view.

The second gripping arm 12B includes a first arm portion 120B extending in the opposite direction to the X-axis direction (leftward in FIG. 3), a second arm portion 121B extending in the Y-axis direction (upward in FIG. 3) from the tip end (end portion opposite the X-axis direction) of the first arm portion 120B, and a third arm portion 122B extending in the X-axis direction (rightward in FIG. 3) from the tip end (end portion on the Y-axis direction side) of the second arm portion 121B. That is, the second gripping arm 12B is configured in a shape that is roughly an inverted U-shape in a plan view.

The gripping arms 12A-12B are attached to the vehicle body 10 so that the first arm portion 120A and the first arm portion 120B are arranged on the same imaginary straight line parallel to the X-axis direction. The second arm portion 121A and the second arm portion 121B are configured so that their lengths in the Y-axis direction are the same. The first arm portion 120A and the first arm portion 120B may have the same length in the X-axis direction or may have different lengths. Similarly, the third arm portion 122A and the third arm portion 122B may have the same length in the X-axis direction or may have different lengths.

However, in the first gripping arm 12A, it is preferable that the third arm portion 122A is formed so that the length in the X-axis direction is shorter than that of the first arm portion 120A. In one example, as shown in FIG. 3, the third arm portion 122A may be protruded from the end of the second arm portion 121A on the Y-axis direction side in the opposite direction to the X-axis direction (to the left in FIG. 3) even if only slightly. Similarly, in the second gripping arm 12B, it is preferable that the third arm portion 122B is formed so that the length in the X-axis direction is shorter than that of the first arm portion 120B. This makes it possible to keep the distance between the first gripping arm 12A and the second gripping arm 12B small when the cart 20 is called between the first gripping arm 12A and the second gripping arm 12B. Therefore, even if the space around the cart 20 is relatively narrow, it is possible to call in and hold the cart 20.

Here, the gripping arms 12A-12B may be formed into a plate shape with a rectangular cross-sectional shape. In this case, the gripping arms 12A-12B may be formed into a plate shape in which the width of the upper and lower faces is greater than the height of the side faces, as shown in FIG. 1. The gripping arms 12A-12B may also be formed into a plate shape in which the height of the side faces is greater than the width of the upper and lower faces. However, the shape of the gripping arms 12A-12B can be flexibly changed depending on the embodiment.

In this embodiment, a first obstacle sensor 30A and a second obstacle sensor 30B are attached to the first gripping arm 12A and the second gripping arm 12B, respectively. In the example shown in FIG. 3, the first obstacle sensor 30A is attached to the corner between the first arm portion 120A and the second arm portion 121A of the first gripping arm 12A. The second obstacle sensor 30B is attached to the corner between the second arm portion 121B and the third arm portion 122B of the second gripping arm 12B.

The first obstacle sensor 30A and the second obstacle sensor 30B are attached at positions shown in FIG.
The positions of the obstacle sensors 30A and 30B are not limited to those illustrated in the example above, and may be any positions diagonal to each other on the first gripping arm 12A and the second gripping arm 12B. For example, the first obstacle sensor 30A may be attached to a corner between the second arm portion 121A and the third arm portion 122A on the first gripping arm 12A, and the second obstacle sensor 30B may be attached to a corner between the first arm portion 120B and the second arm portion 121B on the second gripping arm 12B.

The first obstacle sensor 30A and the second obstacle sensor 30B are sensors that detect obstacles located around the transport robot 1. As the first obstacle sensor 30A and the second obstacle sensor 30B, it is preferable to use sensors that can detect obstacles located within a range of 270 degrees or more from the center of the first obstacle sensor 30A and the second obstacle sensor 30B. As such a first obstacle sensor 30A and the second obstacle sensor 30B, a LiDAR, a depth sensor, a camera, or the like can be used.
This allows the first obstacle sensor 30A and the second obstacle sensor 30B to detect obstacles located within a 360-degree range centered on the transport robot 1 in a plan view.

In addition, in this embodiment, as shown in Figs. 1 and 2, an operation panel 18 is attached to the second gripping arm 12B via a frame 17. The frame 17 may be configured by combining a plurality of pillars erected in the Z-axis direction from the upper surface of the first gripping arm 12A and beams erected between the pillars. In the example shown in Figs. 1 and 2, the frame 17 is configured to be approximately L-shaped in plan view, but is not limited to being approximately L-shaped, and may have any shape that does not protrude inward from the second gripping arm 12B in plan view.

The operation panel 18 is a device for an operator or the like to input information necessary for transporting the cart 20. Examples of information necessary for transporting the cart 20 include the position of the cart 20 to be transported, the position of the transport destination, the transport route, the transport timing, and the width of the cart 20. As a result, the transport robot 1 can transport the cart 20 by controlling the mecanum wheels 11 and the actuators 14 according to the information input to the operation panel 18. The operation panel 18 may be configured to output a screen or sound to alert people located near the transport robot 1 while the transport robot 1 is traveling. As an example, the operation panel 18 may display information indicating the passage of the transport robot 1 or information indicating the traveling direction of the transport robot 1 on a screen using characters or symbols, or output sound.

(Grip arm mounting structure)
Next, the mounting structure of the gripping arms 12A-12B to the vehicle body 10 will be described with reference to Fig. 4. Fig. 4 is a side view focusing on the mounting portion of the gripping arms 12A-12B on the vehicle body 10.

As shown in FIG. 4, a first track rail 123A extending in the X-axis direction is laid on the underside of the first arm portion 120A of the first gripping arm 12A. A first carriage 15A is assembled to the first track rail 123A so as to be movable linearly relative to the longitudinal direction of the first track rail 123A. As an example, the first carriage 15A is assembled to the track rail 16 via a number of rolling elements (balls, rollers, etc.) that roll in the rolling grooves of the first track rail 123A and circulate in a circulation path within the first carriage 15A.

The first carriage 15A is fixed to the upper surface of the vehicle body 10. As a result, the first arm portion 120A of the first gripping arm 12A is linearly guided by the first track rail 123A and the first carriage 15A, allowing it to move forward and backward along the X-axis direction. As a result, the entire first gripping arm 12A is supported by the vehicle body 10 in a state in which it can move forward and backward along the X-axis direction.

A second track rail 123B extending in the X-axis direction is laid on the underside of the first arm portion 120B of the second gripping arm 12B. A second carriage 15B is assembled to the second track rail 123B so as to be movable linearly relative to the second track rail 123B along the longitudinal direction of the second track rail 123B. The method of assembling the second carriage 15B to the second track rail 123B may be the same as that of the first carriage 15A.

The second carriage 15B is fixed to the upper surface of the vehicle body 10. As a result, the first arm portion 120B of the second gripping arm 12B is linearly guided by the second track rail 123B and the second carriage 15B, allowing it to move forward and backward along the X-axis direction. As a result, the entire second gripping arm 12B is supported by the vehicle body 10 in a state in which it can move forward and backward along the X-axis direction.

The track rails 123A-123B and carriages 15A-15B are attached to the vehicle body 10 so that the first arm portion 120A and the first arm portion 120B are positioned on the same imaginary straight line parallel to the X-axis direction. Furthermore, the track rails 123A-123B are attached to the first arm portions 120A-120B and the carriages 15A-15B are attached to the vehicle body 10 in such a way that the ground clearance of the gripping arms 12A-12B is higher than the minimum ground clearance of the part of the cart 20 excluding the casters 210 (the part on which objects are loaded). As an example, a base portion for raising the mounting position of the carriages 15A-15B above the top surface of the vehicle body 10 may be provided on the vehicle body 10, and the carriages 15A-15B may be attached to the base portion.

A pair of screw shafts 13A-13B extending along the X-axis direction are attached to the vehicle body 10. At this time, the pair of screw shafts 13A-13B are arranged in series on a virtual collinear line parallel to the X-axis direction, and are connected to each other so as to be rotatable integrally via an actuator 14, which will be described later. In this embodiment, the pair of screw shafts 13A-13B are formed so that the screw grooves are in opposite directions (left and right threads).

In the following, of the pair of screw shafts 13A-13B, the screw shaft 13A located on the X-axis side (right side in FIG. 4) will be referred to as the first screw shaft 13A, and the screw shaft 13B located on the opposite side to the X-axis side (left side in FIG. 4) will be referred to as the second screw shaft 13B. However, when referring to the first screw shaft 13A and the second screw shaft 13B collectively, they will be referred to as the screw shafts 13A-13B.

A first slip nut 16A is attached to the first screw shaft 13A. The first slip nut 16A is connected to the first arm portion 120A of the first gripping arm 12A. A second slip nut 16B is attached to the second screw shaft 13B. The second slip nut 16B is connected to the first arm portion 120B of the second gripping arm 12B.

The actuator 14 rotates the first screw shaft 13A and the second screw shaft 13B together. Since the first screw shaft 13A and the second screw shaft 13B have thread grooves in opposite directions, when the first screw shaft 13A and the second screw shaft 13B are rotated together by the actuator 14, the first slip nut 16A and the second slip nut 16B move in opposite directions along the X-axis direction. In other words, by changing the direction of rotation of the first screw shaft 13A and the second screw shaft 13B by the actuator 14, the first slip nut 16A and the second slip nut 16B can be moved closer to and farther away from each other. Accordingly, the first grip arm 12A connected to the first slip nut 16A and the second grip arm 12B connected to the second slip nut 16B can be moved closer to and farther away from each other along the X-axis direction.

Here, as shown in Fig. 1 and Fig. 4, it is desirable that the screw shafts 13A-13B and the actuator 14 are attached to the vehicle body 10 so as to be disposed on the side opposite to the Y-axis direction of the vehicle body 10 and at a position lower than the upper surface of the vehicle body 10. This allows the maximum ground clearance of the parts of the transport robot 1 other than the gripping arms 12A-12B to be as low as possible. As a result, when the vehicle body 10 is slipped under the cart 20, it is possible to prevent the parts other than the gripping arms 12A-12B from interfering with the cart 20. Furthermore, even if the minimum ground clearance of the parts of the cart 20 excluding the casters 210 (parts on which objects are loaded) is relatively low, it becomes possible for the vehicle body 10 to slip under the cart 20.

(Actuator)
Next, the configuration of the actuator 14 will be described with reference to FIG. 5. FIG. 5 is an enlarged cross-sectional view of the actuator 14 and its surroundings. In one example, the actuator 14 is an electric motor that rotates a shaft 140. In this embodiment, the shaft 140 is rotatably supported by a housing 142 via a cross roller bearing 141. An end of the shaft 140 on the X-axis direction side (right side in FIG. 5) is coupled to the first screw shaft 13A via a first rigid coupling 142A. In addition, an end of the shaft 140 on the opposite side to the X-axis direction (left side in FIG. 5) is coupled to the second screw shaft 13B via a second rigid coupling 142B.

When the actuator 14 configured as described above rotates the shaft 140, the first screw shaft 13A and the second screw shaft 13B rotate integrally with the shaft 140. Since the first screw shaft 13A and the second screw shaft 13B have thread grooves facing in opposite directions, the first slip nut 16A attached to the first screw shaft 13A and the second slip nut 16B attached to the second screw shaft 13B move in opposite directions along the X-axis direction, and accordingly the first gripping arm 12A and the second gripping arm 12B move in opposite directions along the X-axis direction.

1 and 2, the first gripping arm 12A and the second gripping arm 12B are in the closest state to each other. When the actuator 14 rotates the shaft 140 in the first rotation direction in this state, the first slip nut 16A and the second slip nut 16B move away from each other along the X-axis direction, as shown in FIGS. 6 and 7, and the first gripping arm 12A and the second gripping arm 12B also move away from each other along the X-axis direction. Also, when the actuator 14 rotates the shaft 140 in a second rotation direction opposite to the first rotation direction in a state in which the first gripping arm 12A and the second gripping arm 12B are separated from each other as shown in FIGS. 6 and 7, the first slip nut 16A and the second slip nut 16B move closer to each other along the X-axis direction, and the first gripping arm 12A and the second gripping arm 12B also move closer to each other along the X-axis direction. This allows the first gripping arm 12A and the second gripping arm 12B to move closer to and away from each other with a single actuator 14.

As described above, when the first gripping arm 12A and the second gripping arm 12B are moved toward and away from each other, the thrust load of the first screw shaft 13A and the second screw shaft 13B acts on the shaft 140 of the actuator 14. By applying such thrust load to the cross roller bearing 141, it is possible to improve the rotational accuracy of the first screw shaft 13A and the second screw shaft 13B while ensuring the durability of the actuator 14.

(Effects of the embodiment)
Here, the effects of this embodiment will be described with reference to Fig. 8 to Fig. 10. Fig. 8 is a diagram showing the operation of the transport robot 1 when gripping the cart 20 with the gripping arms 12A-12B. Fig. 9 is a perspective view showing the transport robot 1 in a state where the gripping arms 12A-12B grip the cart 20. Fig. 10 is a side view of the transport robot 1 in a state where the gripping arms 12A-12B grip the cart 20.

When the cart 20 placed in a predetermined location is to be grasped by the gripping arms 12A-12B, first, as shown in FIG. 8(a), the Mecanum wheels 11 move the transport robot 1 to a position where the X-axis direction of the transport robot 1 and the width direction of the cart 20 are parallel and the cart 20 and the vehicle body 10 face each other. When the transport robot 1 is not transporting the cart 20 (when the transport robot 1 is traveling alone), the gripping arms 12A-12B are controlled to be closest to each other as shown in FIG. 1 and FIG. 2. This makes it possible to prevent the transport robot 1 traveling alone from obstructing the passage of people in the vicinity. Furthermore, since the transport robot 1 can travel through narrow passages, the options for the travel route of the transport robot 1 traveling alone can be increased.

When the transport robot 1 arrives at a position where the X-axis direction of the transport robot 1 and the width direction of the cart 20 are parallel and the cart 20 and the vehicle body 10 face each other, as shown in FIG. 8 (b), the actuator 14 rotates the shaft 140 in the first rotation direction. As a result, the first screw shaft 13A and the second screw shaft 13B rotate in the first rotation direction together with the shaft 140. In response to this, the first slip nut 16A and the second slip nut 16B move away from each other along the X-axis direction. At that time, the first gripping arm 12A connected to the first slip nut 16A is guided linearly in the X-axis direction by the first track rail 123A and the first carriage 15A. Also, the second gripping arm 12B connected to the second slip nut 16B is guided linearly in the opposite direction to the X-axis direction by the second track rail 123B and the second carriage 15B. As a result, the first gripping arm 12A and the second gripping arm 12B move away from each other along the X-axis direction. The actuator 14 rotates the shaft 140 in the first rotation direction until the gap between the tip end (the end opposite the X-axis direction) of the third arm portion 122A and the tip end (the end on the X-axis direction side) of the third arm portion 122B becomes larger than the width of the cart 20. At that time, the amount of rotation (rotation angle) of the shaft 140 in the first rotation direction may be determined (calculated) according to the width of the cart 20 input to the operation panel 18.

When the shaft 140 is rotated in the first rotation direction until the gap between the first gripping arm 12A and the second gripping arm 12B (the gap between the tip of the third arm portion 122A and the tip of the third arm portion 122B in the X-axis direction) becomes larger than the width of the cart 20, as shown in FIG. 8(c), the four Mecanum wheels 11 move parallel to the Y-axis direction to move the transport robot 1 so that at least a portion of the vehicle body 10 slides under the cart 20 and calls the cart 20 into the gap between the first gripping arm 12A and the second gripping arm 12B.

9 and 10, the transport robot 1 in this embodiment is configured so that the maximum ground clearance (total height) of the parts other than the gripping arms 12A-12B is lower than the minimum ground clearance of the part of the cart 20 excluding the casters 210 (parts on which objects are loaded), and the width (length in the X-axis direction) of the parts other than the gripping arms 12A-12B is narrower than the gap between two adjacent casters 210 in the width direction of the cart 20. This allows the cart 20 to be called into the gap between the first gripping arm 12A and the second gripping arm 12B without interfering with the cart 20 with the parts of the transport robot 1 other than the gripping arms 12A-12B. In addition, in the transport robot 1 in this embodiment, the lengths of the third arm portion 122A and the third arm portion 122B in the X-axis direction are shorter than the first arm portion 120A and the first arm portion 120B, respectively. This makes it possible to minimize the distance that the first gripping arm 12A and the second gripping arm 12B are separated when the cart 20 is called between them. As a result, it becomes possible to call in the cart 20 even when the space around the cart 20 is relatively narrow.

When the cart 20 is drawn into the gap between the first gripping arm 12A and the second gripping arm 12B, as shown in FIG. 8(d), the actuator 14 rotates the shaft 140 in the second rotation direction. As a result, the first screw shaft 13A and the second screw shaft 13B rotate in the second rotation direction together with the shaft 140. In response, the first slip nut 16A and the second slip nut 16B approach each other along the X-axis direction. At that time, the first gripping arm 12A connected to the first slip nut 16A is guided linearly in the opposite direction to the X-axis direction by the first track rail 123A and the first carriage 15A. Also, the second gripping arm 12B connected to the second slip nut 16B is guided linearly in the X-axis direction by the second track rail 123B and the second carriage 15B. As a result, the first gripping arm 12A and the second gripping arm 12B approach each other along the X-axis direction. The actuator 14 rotates the shaft 140 in the second rotation direction until the distance between the inner surface of the second arm portion 121A and the inner surface of the second arm portion 121B in the X-axis direction becomes approximately equal to the width of the cart 20. At that time, the amount of rotation (rotation angle) of the shaft 140 in the second rotation direction may be determined (calculated) according to the width of the cart 20 input to the operation panel 18 and the amount of rotation of the shaft 140 in the first rotation direction described above with reference to FIG. 8(b).

When the shaft 140 is rotated in the second rotation direction until the distance between the inner surface of the second arm portion 121A and the inner surface of the second arm portion 121B in the X-axis direction becomes approximately equal to the width of the cart 20, the cart 20 is gripped by the first gripping arm 12A and the second gripping arm 12B, as shown in Figures 9 and 10. The Mecanum wheel 11 then drives the transport robot 1 to the specified transport destination. At that time, the propulsive force of the transport robot 1 is transmitted to the cart 20 via the gripping arms 12A-12B, causing the casters 210 of the cart 20 to roll in the direction of travel of the transport robot 1. This causes the cart 20 to travel using the propulsive force of the transport robot 1. Thus, the transport robot 1 can transport the cart 20 to the specified transport destination.

The transport robot 1 described in this embodiment can transport the cart 20 by gripping it with the gripping arms 12A-12B. This eliminates the need to lift up the cart 20 or to connect the cart 20 to the transport robot 1 with a dedicated mechanism. In other words, the transport robot 1 can transport objects even if they are not dedicated carts that have been reinforced, grooved, or otherwise processed. As a result, the versatility of the transport robot 1 can be increased, and the cost of introducing the transport robot 1 can be reduced accordingly.

In addition, with the transport robot 1 described in this embodiment, the gripping arms 12A-12B can be kept close to each other when the cart 20 is not being transported, allowing the transport robot 1 to be made smaller. This increases the mobility and safety of the transport robot 1 when it travels alone, and also makes it easier to ensure storage space.

Furthermore, according to the transport robot 1 described in this embodiment, each of the gripping arms 12A-12B is formed in a roughly U-shape in plan view, and the openings of the U-shapes are arranged to face each other, so that the cart 20, which is rectangular in plan view, can be stably gripped. For example, the second arm units 121A-121B can suppress the change in posture of the cart 20 in the X-axis direction, and the first arm units 120A-120B and the third arm units 122A-122B can suppress the change in posture of the cart 20 in the Y-axis direction. Therefore, the change in posture of the cart 20 when the transport robot 1 transports the cart 20 can be suppressed. Furthermore, when the gripping arms 12A-12B are gripping the cart 20, the third arm portion 122A-122B functions as a locking portion that restricts movement of the cart 20 in the Y-axis direction, preventing the cart 20 from slipping out of between the gripping arms 12A-12B in the Y-axis direction during transport.

In addition, according to the transport robot 1 described in this embodiment, the first obstacle sensor 30A and the second obstacle sensor 30B are disposed at positions diagonal to the gripping arms 12A-12B in a plan view. As a result, when the gripping arms 12A-12B grip the cart 20, as shown in FIG. 9(d), the first obstacle sensor 30A and the second obstacle sensor 30B are positioned on the extension of the diagonal of the cart 20 in a plan view. In addition, each of the first obstacle sensor 30A and the second obstacle sensor 30B can detect obstacles present within a 270-degree range centered on the sensor itself. Therefore, the first obstacle sensor 30A and the second obstacle sensor 30B can detect obstacles present within a 360-degree range centered on the cart 20 in a plan view. In other words, the number of obstacle sensors to be installed can be minimized while suppressing the occurrence of blind spots. Therefore, the expandability of the transport robot 1 with respect to the installation of obstacle sensors can be ensured.

Furthermore, according to the transport robot 1 described in this embodiment, a single actuator 14 can move the pair of gripping arms 12A-12B toward and away from each other. In addition, the thrust load of the screw shafts 13A-13B can be borne by the cross roller bearing 141, so the durability of the actuator 14 can be ensured while improving the rotational accuracy of the screw shafts 13A-13B.

<Other embodiments>
In the above embodiment, the gripping arms 12A-12B are exemplified as being substantially U-shaped in plan view, but the shape of the gripping arms 12A-12B may be changed as appropriate depending on the shape of the cart to be transported. Each of the gripping arms 12A-12B may be formed in a substantially arc shape in plan view and attached to the vehicle body 10 so that the openings of the arcs face each other. This allows the gripping arms 12A-12B to stably grip a cart that is circular in plan view.

In the above embodiment, an example was described in which the first obstacle sensor 30A and the second obstacle sensor 30B were attached to the gripping arms 12A-12B. However, instead of or in addition to the first obstacle sensor 30A and the second obstacle sensor 30B, a contact sensor that detects contact with an obstacle may be attached to the gripping arms 12A-12B. In this case, the contact sensor may be provided on the outer surface of each of the gripping arms 12A-12B in a plan view. As a result, when the transport robot 1 is gripping the cart, the contact sensor is disposed outside the cart in a plan view. Therefore, it is possible to detect contact with an obstacle while preventing the cart from coming into contact with the obstacle. As a result, it is possible to ensure the extensibility of the transport robot 1 with respect to the attachment of the contact sensor.

In addition to or in place of the contact sensor described above, a shock absorber such as a bumper may be attached to the outer surface of the gripping arms 12A-12B. When using a contact sensor and a shock absorber together, the contact sensor may be attached to the outer surface of the shock absorber in a plan view. This means that when the transport robot 1 is gripping the cart, the shock absorber is positioned outside the cart in a plan view. This makes it possible to prevent the cart from coming into contact with an obstacle, and also to reduce the impact when the cart comes into contact with an obstacle. As a result, the expandability of the transport robot 1 for the attachment of a shock absorber can be ensured.

In addition, a contact sensor may be attached to the inner surface of the gripping arms 12A-12B in plan view. This allows the actuator 14 to automatically stop the rotational drive of the shaft 140 when the contact sensor detects contact with the cart during the gripping operation of the gripping arms 12A-12B.

In the above-described embodiment, the gripping arms 12A-12B have a constant length of the second arm portions 121A-121B, but the length of the second arm portions 121A-121B may be variable (retractable). In this case, the extension and retraction of the second arm portions 121A-121B may be performed manually, or may be performed mechanically using a linear actuator or the like. This allows the length of the gripping arms 12A-12B in the Y-axis direction to be changed according to the depth of the cart, thereby further enhancing the versatility of the transport robot 1.

If the object to be transported by the transport robot 1 is a basket cart with a mesh-like bottom surface on which the object is loaded, or a cart with ribs or other irregularities on the bottom surface on which the object is loaded, an extendable movable pin may be attached to the top surface of the vehicle body 10, and the movable pin may be engaged with the gaps in the mesh or the recesses in the irregularities when the object is gripped by the gripping arms 12A-12B.

1: Transport robot, 10: Body, 11: Mecanum wheel, 12A-12B: Grip arm, 123A-123B: Track rail, 13A-13B: Screw shaft, 14: Actuator, 15A-15B: Carriage, 16A-16B: Sliding nut, 20: Cart, 30A-30B: Obstacle sensor

Claims (6)

A transport robot that transports an object by slipping at least a part of a vehicle body under the object,
A traveling unit attached to the vehicle body and capable of traveling in a plurality of directions including a first direction in a plan view;
A pair of gripping arms for gripping the transport object;
a pair of guide devices attached to the vehicle body and configured to linearly guide the pair of gripping arms along a second direction perpendicular to the first direction in a plan view;
a drive unit that moves the pair of gripping arms toward and away from each other along the second direction;
Equipped with
Transport robot. The pair of gripping arms are each formed in a substantially U-shape in a plan view, and are arranged so that openings of the U-shape face each other.
The transport robot according to claim 1 . Each of the pair of gripping arms includes a first arm portion extending parallel to the second direction in a plan view, a second arm portion extending parallel to the first direction from a tip end of the first arm portion, and a third arm portion extending parallel to the first arm portion from a tip end of the second arm portion,
The length of the third arm portion in the second direction is shorter than the length of the first arm portion in the second direction.
The transport robot according to claim 2 . The pair of gripping arms is provided with a pair of obstacle sensors for detecting an obstacle,
The pair of obstacle sensors are disposed at diagonal positions on the pair of gripping arms in a plan view.
The transport robot according to claim 2 . Further comprising a pair of contact sensors provided on outer surfaces of the pair of gripping arms in a plan view and configured to detect contact with an obstacle;
The transport robot according to claim 2 . The drive unit is
A pair of screw shafts extending along the second direction, the pair of screw shafts having screw grooves in opposite directions;
A pair of nuts assembled to each of the pair of screw shafts, the pair of nuts being respectively connected to the pair of gripping arms;
an actuator including a rotating shaft connecting the pair of screw shafts to each other and a cross roller bearing supporting the rotating shaft so as to be freely rotatable, the actuator rotating the rotating shaft;
Equipped with
The transport robot according to claim 1 .

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