JP2799433B2 - How to fix an object under zero gravity - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method that does not cause fluctuation when an object gripped under zero gravity such as outer space is separated.

[0002]

2. Description of the Related Art When performing a zero gravity experiment or work in a falling facility or a spacecraft, the experiment or working space is limited.
In a state where human beings cannot intervene, there is a demand for a technique of separating an object without imparting motion and fixing it in a weightless space.

Conventionally, in space development technology, robot hands and docking mechanisms have been developed as devices for capturing floating objects.

[0004] On the other hand, there is a space shuttle arm as a device for releasing an object such as an artificial satellite in zero gravity as a detaching device. Also, although not in zero gravity, a fall capsule is placed in a fall facility of a zero gravity experiment experiment by using an electromagnet or a magnet. There is a large-scale separation device that separates using hydraulic pressure.

[0005]

However, the use of a space shuttle arm to release an object under zero gravity without imparting initial movement requires the operation of a skilled operator.

In the above-described large-scale separation device, an object is separated by using a hydraulic pressure or an electromagnet. However, this requires a large-scale device for controlling the hydraulic pressure and a large amount of electric power. Cannot be mounted on the device.

On the other hand, the inventors of the present invention have previously installed on a rail a pair of separating devices having opposing fingers operated by a command signal, and moved the separating device on the rail in the opposite direction. Provide a drive mechanism to
Furthermore, a device for fixing an object under zero gravity has been proposed in which a gripping portion of the object is provided through a mechanism for stably gripping the tip of the finger (Japanese Patent Application No. 8-84099).

In this device, the object is stably gripped, and at the time of separation, the separation device is moved on the rail so as not to vibrate the object, and the finger is simultaneously separated from the object by the command signal. Since the object is not given extra motion, the object has a feature that the object can be floated without giving an initial motion under zero gravity.

However, in this device, the object is gripped between the fingers under gravity, and then the fingers gripping the object are operated in a direction to open each other by the command signal under zero gravity to fix the object under zero gravity. However, when grasping an object between fingers under gravity, force distortion occurs due to the eccentricity of the center of gravity or the difference in frictional force due to one-sided tightening. However, there is a problem in reproducibility such that the object cannot be completely stopped due to distortion of the remaining force, or the object moves when gripping the object under zero gravity.

[0010]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention grasps an object between fingers protruding in the opposite direction under gravity, and then causes the fingers grasping the object by a command signal under zero gravity to each other. In the method of operating in the opening direction and fixing the object under zero gravity, the fingers holding the object by the command signal under zero gravity are operated in the direction of opening each other for a short time,
Further, the present invention proposes a method of operating in a direction of approaching each other for a short time and then operating in a direction in which fingers mutually open to fix an object under the original weightlessness.

[0011]

In other words, prior to operating the fingers in the direction of opening each other to fix the object under the original weightless state, the fingers are operated in the direction of opening each other for a short time and then moved in the direction of approaching each other for a short time. The object is gripped between the fingers in a state where the distortion of the force generated when the object is gripped between the fingers under gravity is removed.

As described above, when the object is re-gripped in a state where the distortion of the force is removed, and then the fingers are moved in the direction in which the fingers are opened to fix the object under the original weightlessness, the object is surely held under the weightlessness. Therefore, even when the center of gravity is eccentric when gripping under gravity, the object can be easily stopped.

The operation of opening the fingers to each other for fixing the object under the original weightless state is, for example, about 2 seconds, whereas the opening and closing operation of the fingers performed earlier is performed in a short time, for example, about 0.5 to 1 second. is there.

In the present invention, after the distortion of the force generated when the object is gripped between the fingers under gravity is released under zero gravity,
As a device for moving fingers grasping an object in a direction to open each other by a command signal, a pair of separation devices which are installed on a rail and have fingers operated by a command signal in opposition can be used.

In this device, the fingers gripping the object are operated by a drive mechanism such as a motor, a pneumatic pressure, a hydraulic pressure, etc., so that all the fingers are simultaneously separated from the object at the same time as the command signal, so that no extra movement is given to the object. To do.

On the other hand, the pair of separating devices provided on the rails are configured to be moved in a direction of approaching or separating from each other by a driving mechanism in response to a command signal.

That is, by moving the separating device on the rail, an uncertain movement due to vibration at the time of separating is not given to the object, and the rigidity of the entire separating mechanism is secured.

The driving mechanism of the pair of separating devices provided on the rail is constituted by attaching the pair of separating devices to both sides of an endless timing belt driven by, for example, a motor.

On the other hand, the drive mechanism of the finger and the separating device is provided with a timing device constituted by a mechanical element such as an electric circuit or a gear in order to operate by a command signal.

It is preferable that a tip of the finger is provided with a grip portion for the object via a mechanism for holding the object stably, whereby the stress applied to the object mounted in a gravitational environment is reduced.
Grasping can be stabilized.

That is, by interposing a mechanism for stably gripping between the tip of the finger and the gripping portion, the stress can be relaxed regardless of the shape and the target object can be stably held.

Here, the mechanism for holding stably is as follows.
Conventionally used self-centering mechanisms such as self-centering roller bearings, self-centering bearings, self-centering ball bearings, and self-centering rollers can also be used.

When the target object cannot be stably held on a plane, the shape of the gripping surface may correspond to the target object. For example, when the target object is a sphere or a triangular pyramid, A groove may be formed on the gripping surface as described above.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment carried out using a dropping facility of a zero-gravity experiment center (underground zero-gravity experiment center in Kamisunagawa-cho, Hokkaido). 1 and 2 show a separating device main body 1 used in a dropping device.

The experimental space that can be used in the fall facility is 870 [W] ×
It is 870 [L] x 443 [H] [mm], and all the devices including the power supply must be mounted therein. Therefore, the size of the main body 1 is reduced.

A small robot for a space robot experiment is used as an object to be separated. In this embodiment, a rectangular parallelepiped a is used as an object to be separated.

On the other hand, a rail 2 is provided on one side in the main body 1, and a pair of separation devices 3 and 3 are installed on the rail 2 and the separation devices 3 and 3 are operated in opposition by command signals. Fingers 4 are provided, and a gripper 6 for the object a is provided at the tip of the finger 4 via a spherical bearing 5.

In this embodiment, an endless timing belt 8 laid on pulleys 7 and 7 is provided along the rail 2 as a drive mechanism of the separation devices 3 and 3.
7 and a motor 10 for driving the rotating shafts 9
Separating devices 3 and 3 are fixed to both sides of the endless timing belt 8, respectively.

A spring plunger 11 for equilibrium support is provided between the finger 4 and the grip 6.

In the above configuration, the object a is held under the gravity by the spherical bearings 5 via the grippers 6, 6
It is held stable between.

FIG. 4 shows a command signal of the finger 4. When a drop command is issued, a command signal for opening between the fingers 4 and 4 is first issued for 0.5 to 1 second, and the finger signal is issued for the next 0.5 to 1 second. A command signal for closing between fingers 4 and 4 is issued, and a command signal for opening between fingers 4 and 4 is issued for the last two seconds.

On the other hand, as shown in FIG. 5A, a timing circuit 12 is provided in the drive mechanism of the separation devices 3 and 3 composed of the motor 10, and when a command signal as described above is received, the timing Circuit 12 applies the first 0.
It is operated to open between the gripping parts 6 and 6 for 5 to 1 second, close for the next 0.5 to 1 second, and close for the last 2 seconds.

Specifically, for the first 0.5 to 1 second, the motor
By means of 10, the rotating shaft 9 of the pulley is driven so that the separating devices 3 and 3 move in the opposite direction, in the next 0.5 to 1 second to move in the approaching direction, and in the last 2 seconds in the opposite direction. Drive to move.

Thus, the gripper 6, which grips the object a,
During the 6th period, the first 0.5-1 second is separated, the next 0.5-1 second is approached, and again in the last 2 seconds.

The distortion of the force generated when the object "a" is gripped between the gripping parts 6 and 6 under gravity is first caused by the gripping part 6.6.
It is released during the separation, and the gripping portions 6 and 6 approach each other to re-grip the object a. Finally, the gripping portions 6 and 6 are separated again to separate the object a under zero gravity.

Therefore, according to the present invention, when the object a is gripped between the gripping portions 6 and 6 under gravity, even if the force is distorted due to the eccentricity of the center of gravity or the difference in frictional force due to one-sided tightening,
After releasing this, to separate the object a under zero gravity,
It was confirmed that the object a could be reliably stopped under zero gravity.

In this embodiment, the object to be separated is a rectangular parallelepiped, so that the holding surface of the holding part 6 is used as a plane. However, when the object to be separated is a sphere or a triangular pyramid, FIG.
By providing the triangular groove 13 on the gripping surface as shown in (A) and (B), the object a can be stably held.

[0038]

In summary, according to the present invention, even when a force is distorted due to the eccentricity of the center of gravity or a difference in frictional force due to one-sided tightening when gripping an object between fingers under gravity, An object can be easily stopped still under zero gravity.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of the present invention.

FIG. 2 is a plan view with a part cut away from the above.

FIG. 3 is a side view showing a driving mechanism of the separation device according to the first embodiment;

FIG. 4 shows an example of a command signal according to the present invention.

5A is a diagram illustrating a timing circuit and a driving mechanism of a separating device, and FIG. 5B is a diagram illustrating an object and a gripping unit;

FIG. 6A is a plan view showing an embodiment for stably holding a sphere, and FIG. 6B is a plan view showing an embodiment for stably holding a triangular pyramid;

[Explanation of symbols]

 1 is a separating device body 2 is a rail 3 is a separating device 4 is a finger 5 is a spherical bearing 6, 6 is a gripper 7, 7 is a pulley 8 is an endless timing belt 9 is a pulley rotating shaft 10 is a motor 11 is a spring plan Jar 12 is a timing circuit 13 is a groove a is an object

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B64G 1/66 B64G 1/64 B25J 13/00

Claims (1)

(57) [Claims] 1. A method of fixing an object grasped between fingers protruding in an opposing manner in a direction of increasing the distance between fingers and fixing the object under zero gravity, wherein the finger grasping the object by a command signal under zero gravity is provided. Move in the direction of opening each other for a short time,
A method of fixing an object under zero gravity, further comprising: moving the fingers in a direction approaching each other for a short time, and then operating the fingers in a direction in which the fingers are opened to fix the object under the original zero gravity.