Anti-tipping device

Abstract

This invention provides a robot tipping prevention device that can easily prevent a work robot from tipping over over a wide area without the need for a locking mechanism. [Solution] A permanent magnet 2 and an electromagnet 3 are provided at the bottom of a trolley 11 equipped with a robotic arm 13 for work and capable of moving on the floor F. The magnetic field Mp of the permanent magnet 2, which exerts an attractive force Sf on the floor F, is strengthened or weakened by the magnetic field Me of the electromagnet 3.

Description

Technical Field

[0001] The present invention relates to a fall prevention device, and particularly to a fall prevention device using electromagnetic attraction force.

Background Art

[0002] Working robots equipped with robotic arms on carts movable on the floor are increasingly being used in factories, warehouses, etc. In such working robots, if the arm is extended greatly or a heavy object is grasped at the tip of the extended arm, the center of gravity of the robot may move significantly to the side along the floor and the robot may fall. Therefore, for example, in Patent Document 1, when the robot starts working approaching an external structure, the above-mentioned cart is locked to the external structure to prevent falling, and it is suggested to use electromagnetic force as the driving force of the locking mechanism.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above conventional fall prevention device, the fall prevention of the working robot is only performed near the external structure where the locking mechanism is provided, so the working range is limited, and there is a problem that a strong locking mechanism always needs to be operated regardless of the extension amount of the robotic arm and the lightness or heaviness of the work.

[0005] Therefore, the present invention solves such problems, and an object thereof is to provide a fall prevention device capable of easily preventing the fall of a working robot and other device bodies in a wide range without providing a locking mechanism.

Means for Solving the Problems

[0006] To solve the above problems, the first invention provides a device for preventing an apparatus from tipping over when its center of gravity shifts during operation, thereby generating a tipping moment. The device is provided with a permanent magnet and an electromagnet at the bottom of the apparatus, and the magnetic field of the permanent magnet, which exerts an attractive force on the floor, is strengthened or weakened by the magnetic field of the electromagnet.

[0007] Furthermore, in this second invention, a permanent magnet (2) and an electromagnet (3) are provided at the bottom of a trolley (11) equipped with a robot arm (13) that can travel on a floor (F), and the magnetic field (Mp) of the permanent magnet (2) that exerts an attractive force (Sf) on the floor (F) is strengthened or weakened by the magnetic field (Me) of the electromagnet (3).

[0008] In the first and second inventions, when the magnetic field of a permanent magnet provided at the bottom of the device or trolley reaches a floor that is not entirely or partially made of magnetic material, or has a magnetic material layer formed on its surface, an attractive force acts between the device and the floor. This prevents the device or robot arm from tipping over when its center of gravity shifts during operation, causing a tipping moment, or when the robot arm extends and its center of gravity moves laterally along the floor, causing a tipping moment. In this case, the magnetic field of the permanent magnet can be strengthened or weakened as needed by the magnetic field of the electromagnet. Therefore, if the center of gravity of the device shifts significantly, or the robot arm extends significantly, or the robot arm is working on a heavy object, increasing the tipping moment, the magnetic field of the permanent magnet can be strengthened to increase the attractive force, thereby reliably preventing the working robot from tipping over. On the other hand, when the device or trolley is moving, the magnetic field of the permanent magnet can be weakened to reduce the attractive force, enabling smooth movement while maintaining an appropriate posture.

[0009] As described above, the first and second inventions make it possible to easily prevent the device or robot from tipping over at any position over a wide range without providing a mechanical locking mechanism, and also ensure the smooth movement of the device or robot. In this case, the magnetic field of the electromagnet only needs to be adjusted to strengthen or weaken the magnetic field of the permanent magnet as needed, so unnecessary power consumption can be avoided by appropriately exciting the magnet.

[0010] In this third invention, the permanent magnet (2) and the electromagnet (3) are stacked inside a housing (4) made of a non-magnetic material.

[0011] According to this third invention, the magnetic field of an electromagnet can be efficiently applied to the magnetic field of a permanent magnet.

[0012] In this fourth invention, the housing (4) is made vertically movable.

[0013] In this fourth invention, when tipping prevention is necessary, the housing can be lowered to approach or touch the floor, thereby efficiently generating an attractive force to the floor using the permanent magnet and electromagnet.

[0014] In this fifth invention, the permanent magnet (2) and the electromagnet (3) are oriented vertically and sandwiched together by a plate-shaped yoke (6).

[0015] In this fifth invention, the magnetic field generated by the electromagnet or permanent magnet is concentrated within the yoke, providing a magnetic shielding function, and a strong magnetic field can be efficiently concentrated toward the floor to control the attractive force.

[0016] The symbols in parentheses above are for reference only, indicating the correspondence with the specific means described in the embodiments described later. [Effects of the Invention]

[0017] As described above, the anti-tipping device of the present invention makes it possible to easily prevent the tipping of a device or robot over a wide range of positions without providing a locking mechanism. [Brief explanation of the drawing]

[0018] [Figure 1] This is a schematic side view of a work robot equipped with a fall prevention device according to the first embodiment of the present invention. [Figure 2] This figure shows the magnetic field formed when the electromagnet is not energized. [Figure 3] It is a diagram showing the formed magnetic field when an electric current is applied to an electromagnet to strengthen the magnetic field of a permanent magnet. [Figure 4] It is a diagram showing the formed magnetic field when an electric current is applied in the reverse direction to an electromagnet to weaken the magnetic field of a permanent magnet. [Figure 5] It is a diagram showing the disappearance of the magnetic field when an electric current is applied in the reverse direction to an electromagnet to cancel out the magnetic field of a permanent magnet. [Figure 6] It is a schematic side view of a working robot equipped with an anti-tipping device in the second embodiment of the present invention, showing the state when the housing is raised. [Figure 7] It is a schematic side view of the working robot when the housing is lowered. [Figure 8] It is a schematic side view of a working robot equipped with an anti-tipping device in the fifth embodiment of the present invention. [Figure 9] It is a cross-sectional view of the main part of the anti-tipping device in the sixth embodiment of the present invention.

Embodiments for Carrying out the Invention

[0019] Note that the embodiments described below are merely examples, and various design improvements made by those skilled in the art without departing from the gist of the present invention are also included in the scope of the present invention.

[0020] (First Embodiment) FIG. 1 shows a schematic side view of a working robot 1 equipped with an anti-tipping device. In FIG. 1, the working robot 1 includes a rectangular carriage 11, and traveling wheels 12 are provided on the lower surface of the carriage 11 so that it can travel and move on the floor F. A multi-joint robot arm 13 extending laterally therefrom is provided at the center of the upper surface of the carriage 11, and an object can be grasped by a gripper 131 at the tip of the arm. When the robot arm 13 extends largely laterally as shown in FIG. 1, the center of gravity position of the working robot 1 may move laterally (hereinafter simply referred to as lateral) along the floor F from the center and there is a risk of tipping over.

[0021] Therefore, in this embodiment, a non-magnetic housing 4 containing a permanent magnet 2 and an electromagnet 3 stacked vertically is provided at the bottom center of the trolley 11, forming an anti-tipping device. As a result, the magnetic field Mp of the permanent magnet 2 acts on the floor F as shown in Figure 2, and if the floor F is made of a magnetic material such as iron, or if a magnetic material layer is formed on the base surface of the floor, an attractive force Sf acts between the bottom center of the trolley 11 and the floor F. This prevents the trolley 11, and thus the work robot 1, from tipping over even if the robot arm 13 extends laterally and the center of gravity changes.

[0022] When the robot arm 13 extends widely to the side, or when it performs tasks such as grasping and lifting heavy objects with the gripper 131 at its tip, a large tipping force (tipping moment) acts on it. In this case, as shown in Figure 3, the electromagnet 3 is energized so that its magnetic field Me strengthens the magnetic field Mp of the permanent magnet 2. This increases the attractive force Sf between the lower center of the trolley 11 and the floor F, preventing the working robot 1 from tipping over against the large tipping force.

[0023] When the work robot 1 moves, as shown in Figure 4, the energization of the electromagnet 3 is reversed so that its magnetic field Me weakens the magnetic field Mp of the permanent magnet 3. As a result, the attractive force Sf between the lower center of the trolley 11 and the floor F becomes smaller than when the permanent magnet 3 is used alone, allowing the trolley 11, and thus the work robot 1, to move.

[0024] As shown in Figure 5, if the reverse current of the electromagnet 3 is further increased so that its magnetic field Me cancels out the magnetic field Mp of the permanent magnet 2, the attractive force between the lower center of the trolley 11 and the floor F will be eliminated, and the movement of the work robot 1 will become even smoother. In addition, iron powder and other metal fragments may be attracted to and adhere to the outer surface of the housing 4 by the magnetic fields Mp and Me, but as described above, by eliminating the attractive force Sf, the removal of these attached materials will also become easier.

[0025] Furthermore, the amount of current supplied to the electromagnet 3 and the direction of current supply may be controlled so that the attractive force Sf increases when the robot arm 13 is extended laterally, and decreases when it is retracted and stored in the center.

[0026] Furthermore, in this embodiment, even if the magnetic field of the electromagnet 3 is lost due to a power outage or the like, the magnetic field of the permanent magnet 2 is maintained, so the attractive force to the floor F is not eliminated, and a minimum level of anti-tipping function is provided. In this case, an uninterruptible power supply (UPS) can be installed inside the trolley 11 to prevent the magnetic field of the electromagnet 3 from being lost even in the event of a power outage.

[0027] (Second Embodiment) As shown in Figure 6, a recess 111 that opens downward is formed in the center of the trolley 11, and a housing 4 containing an electromagnet 3 and a permanent magnet 2 stacked vertically is mounted within the recess 111 so as to be able to move up and down by a lifting mechanism (not shown). To prevent tipping, the housing 4 is lowered as shown in Figure 7 to bring it close to or touch the floor F. This allows the magnetic fields Mp,Me of the electromagnet 3 and permanent magnet 2 to be more efficiently applied to the floor F, thereby generating a strong attractive force Sf.

[0028] (Third embodiment) In each of the above embodiments, the vertical positions of the electromagnet 3 and the permanent magnet 2 may be reversed.

[0029] (Fourth Embodiment) In each of the above embodiments, a pair of electromagnets 3 may be provided above and below the permanent magnet 2. This allows the other electromagnet 3 to compensate if one of them malfunctions, improving the reliability of the anti-tipping device. Furthermore, providing multiple electromagnets 3 increases the flexibility of magnetic field control.

[0030] (Fifth embodiment) As shown in Figure 8, a magnetic shielding layer 5 made of a ferromagnetic material or the like is provided on the inner surface of the recess 111 of the trolley 11 so as to surround the outer circumference of the housing 4, which houses the electromagnet 2 and the permanent magnet 3, excluding the bottom surface, in order to prevent the magnetic field Mp,Me from affecting the electronic equipment inside the trolley 11.

[0031] (Sixth Embodiment) As shown in Figure 9, the electromagnet 3 and permanent magnet 2 can be oriented vertically within the housing 4 and sandwiched between plate-shaped yokes 6. With this configuration, the magnetic fields Me and Mp generated by the electromagnet 3 and permanent magnet 2 are concentrated within the yoke 6, providing a magnetic shielding function, and the strong magnetic fields Mp and Me can be efficiently concentrated toward the floor F to control the attractive force Sf.

[0032] (Other embodiments) In the embodiments described above, the present invention was applied to prevent the tipping of a work robot equipped with a robot arm on a trolley. However, the present invention is not limited to work robots, and can be broadly applied to other industrial robots, humanoid robots, mechanisms combining sliders other than robots, extendable conveyors, and other devices that generate a tipping moment when their center of gravity shifts during operation. Furthermore, the permanent magnets in each of the above embodiments may be omitted, and tipping prevention may be achieved solely by the attractive force of the electromagnet. [Explanation of symbols]

[0033] 1...Work robot, 11...Cart, 2...Permanent magnet, 3...Electromagnet, 4...Housing, 5...Magnetic shielding layer, 6...Yoke, F...Floor, Me...Magnetic field of electromagnet, Mp...Magnetic field of permanent magnet.

Claims

1. A device to prevent tipping over of an apparatus that generates a tipping moment due to a shift in its center of gravity during operation, wherein a permanent magnet and an electromagnet are provided at the bottom of the apparatus, and the magnetic field of the permanent magnet, which exerts an attractive force on the floor, is strengthened or weakened by the magnetic field of the electromagnet.

2. A fall prevention device comprising a robotic arm and a trolley capable of moving across a floor, with a permanent magnet and an electromagnet installed at its bottom, wherein the magnetic field of the permanent magnet, which exerts an attractive force on the floor, is strengthened or weakened by the magnetic field of the electromagnet.

3. The tipping prevention device according to claim 1 or 2, wherein the permanent magnet and electromagnet are stacked inside a housing made of a non-magnetic material.

4. The anti-tipping device according to claim 3, wherein the housing is capable of moving up and down.

5. The tipping prevention device according to claim 1 or 2, wherein the permanent magnet and electromagnet are oriented vertically and sandwiched together by a plate-shaped yoke.

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