JPH0768487A - Locking mechanism of force and torque sensor and its releasing method - Google Patents

Abstract

PURPOSE:To provide sure protection of a force and torque sensor in launching a rocket in a locking mechanism and its releasing method of the force and torque sensor applicable to a space robot to execute the attachment/detachment of a connector, the tightening of bolts or the like on the orbit. CONSTITUTION:A locking mechanism of a force and torque sensor consists of a sensor housing 4, a sensor movable part to be supported by the sensor housing through an elastic body 8, a hook 14 which is applied to a force and torque sensor provided with a means to detect the strain generated in the elastic body 8 and provided on the sensor housing in a swayable manner, a pin 16 provided in the vicinity of the tip of the hook 14, and a pedestal 18 where the tip of the pin 16 is seated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a force / torque sensor lock mechanism applicable to a space robot for attaching and detaching connectors and fastening bolts on orbit, and a method for releasing the lock mechanism.

In a space robot, it is necessary to monitor the pushing force and the twisting torque or detect a collision in order to perform a good control at the time of remote control. For this reason, force / torque sensors are generally used in space robots. Since this type of sensor is relatively fragile, its protection is required for practical use.

[0003]

2. Description of the Related Art Conventionally, a sensor housing provided on an arm portion of a robot, a sensor movable portion having one end thereof supported by a sensor housing through an elastic body and a hand portion of the robot fixed to the other end, A force / torque sensor including a means for detecting strain generated in an elastic body is known.

[0004]

Since the rigidity of the elastic body which supports the above-mentioned movable portion of the sensor is comparatively small, the sensor is apt to be damaged or broken due to vibration at the time of launching the rocket, and its protection is required.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a lock mechanism capable of surely protecting a force / torque sensor. It is also an object of the present invention to provide a method for releasing the lock mechanism of the force / torque sensor.

Other objects of the present invention will become apparent from the following description.

[0007]

According to the present invention, a sensor housing provided on an arm portion of a robot, one end of which is supported by the sensor housing via an elastic body, and the other end of which is a hand portion of the robot. A lock mechanism of a force / torque sensor including a fixed sensor movable portion and a means for detecting a strain generated in the elastic body, the lock mechanism being provided on one of the sensor housing and the hand portion so as to be swingable. Hook, a pin provided in the vicinity of the tip of the hook, a pedestal provided on the other of the sensor housing and the hand portion, on which the tip of the pin is seated, and the tip of the pin is seated on the pedestal. Force with locking means for selectively setting the state and the state of not sitting
A locking mechanism for the torque sensor is provided.

Further, according to the present invention, there is provided a method for releasing a lock mechanism for a force / torque sensor according to the present invention, wherein the locking means is slidably provided around the sensor housing, and the pin is mounted on the pedestal. It includes a stopper that locks to the hook in the seated state, and releases the state where the pin is seated on the pedestal by operating the robot and pressing the stop gantry against the metal fitting on the workbench. A method for releasing the lock mechanism of the force / torque sensor is provided.

[0009]

In the force / torque sensor lock mechanism of the present invention, when the lock means selectively sets the state in which the tip of the pin is seated on the pedestal, the relative positional relationship between the sensor movable portion and the sensor housing is established. Even when a large acceleration is applied to the force / torque sensor at the time of launching the rocket, the elastic body is not deformed, and there is no fear of failure or destruction of the force / torque sensor.

[0010]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a partial sectional view of a force / torque sensor showing a first embodiment of the present invention.

A sensor housing 4 is fixed to the tip of the arm portion 2 of the robot. Inside the sensor housing 4, the sensor movable portion 10 is supported by the elastic body 8. The robot hand unit 12 is fixed to the tip of the sensor movable unit 10.

Although not shown, the elastic body 8 is provided with a means such as a strain gauge for detecting a strain generated in the elastic body 8. With this, the force and torque applied to the hand portion 12 are detected. It is like this.

A hook 1 is provided on the outer periphery of the sensor housing 4.
4 is rotatably provided around a shaft 15, and a pin 16 is fixed to the tip of the hook 14. Further, on the outer circumference of the hand portion 12, a pedestal 18 on which the tip of the pin 16 is seated is provided at a position corresponding to the pin 16.

According to this structure, the hook 14 is rotated to the side of the hand portion 12 to maintain the state in which the pin 16 is seated on the pedestal 18, thereby protecting the force / torque sensor from severe vibrations such as rocket launch. Moreover, the lock of the force / torque sensor can be reliably released during operation of the robot after launch.

In the illustrated example, the hook 14 and the pin 16
Two sets of pedestals and pedestals 18 are provided so as to be symmetrical to each other.
You may provide one. Further, the hook may be rotatably provided on the side of the hand portion 12, and the pedestal may be provided on the sensor housing 4 or the arm portion 2.

In this embodiment, the pin 16 has a conical tip to prevent the pin 16 from coming off the pedestal 18 when the lock is released.

By the way, when releasing the lock mechanism of the force / torque sensor as shown in FIG. 1 in outer space, it is conceivable to use dedicated power such as a motor or a solenoid. However, unlocking is generally performed only once prior to the operation of the robot, and therefore it is not preferable to provide a dedicated actuator for a satellite where weight and space are limited.

Therefore, as the power for releasing the lock mechanism of the force / torque sensor on the orbit after launching the rocket, the thrust of the arm of the robot is used instead of preparing a dedicated power. Specifically, a metal fitting for unlocking is attached within the movable range of the robot arm, and the lock is released by rubbing the force / torque sensor lock mechanism of the robot arm on the metal fitting. More specifically, it is as follows.

FIG. 2 is a perspective view of a robot showing a second embodiment of the present invention, and FIG. 3 is a partial cross-sectional view of the lock mechanism of the force / torque sensor and its releasing mechanism shown in FIG. In this embodiment, the locking means for selectively setting whether the tip of the pin 16 is seated on the pedestal 18 or not seated includes a stop ring 30 slidably provided around the sensor housing 4. . The lock 30 is locked to the hook 14 at the time of launching the rocket, and maintains the state in which the pin 16 is seated on the pedestal 18.

The lock releasing mechanism 24 provided on the workbench 20 has a conical protrusion 26 and a metal fitting 28 protruding inside the conical protrusion 26. The arm portion 2 of the robot can be accommodated in the circular return projection 26, and by lowering the arm portion 2 into the circular tubular projection 26 prior to the work of the robot 21, the stop ring 30 is pushed onto the metal fitting 28. Guess
The state where the pin 16 is seated on the pedestal 18 is released.

As described above, according to this embodiment, when the lock mechanism of the force / torque sensor is released on the orbit after launching the rocket, a new actuator is unnecessary, and the launch weight can be reduced. .

Now, when the unlocking method of the lock mechanism as described in the second embodiment of FIG. 2 is carried out in outer space,
It is required to install a metal fitting for unlocking separately from the robot arm, which is not preferable in a space-constrained satellite.

Therefore, the robot arm itself is provided with a mechanism for releasing the lock mechanism, and the rotational force of the rotary shaft of the arm is used as power. Specifically, the lock release mechanism is operated in conjunction with the rotation axis of the arm. This saves space on the satellite. More specifically, it is as follows.

FIG. 4 is a partial sectional view of a robot showing a third embodiment of the present invention. In this embodiment, the sensor housing 4 is rotatably provided with respect to the arm portion 2 of the robot by the bearing 32, and the rotation of the sensor housing 4 is driven by the motor 34 provided in the arm portion 2.

The hook 14 is rotatable about a shaft 15 provided on the hand portion 12 side. In this example, the hook 14 is provided with two pins 16A and 16B and correspondingly two pedestals 18A and 1B.
8B are provided on the hand portion 12 and the sensor housing 4, respectively.

The roller 38 contacts the hook 14 from the outside when the pins 16A and 16B fixed to the hook 14 are seated on the pedestals 18A and 18B, respectively. According to this configuration, after the rocket is launched in the state shown in which the roller 38 is in contact with the hook 14, the sensor housing 4 is rotated by the motor 34 prior to the work of the robot, so that the force / torque sensor can be easily operated. You can unlock it.

When the lock of the force / torque sensor is unlocked in outer space by using the mechanism of the third embodiment shown in FIG. 4, processing of the hook after unlocking becomes a problem. Since the hook is never used again, it may be thrown out into outer space, but in that case, the floating hook may interfere with the subsequent work. Even when the hook is attached to the robot arm, the hook 14 is rotatable with respect to the hand portion 12 in the third embodiment shown in FIG. 4, so that unexpected movement of the hook 14 may damage other portions. Etc. may occur.

Therefore, the released hook is pressed and fixed to the robot arm by the force of a spring or the like so that the operation of the robot arm is not hindered. Specifically, it is as follows.

FIG. 5 is a plan view (A) and a side view (B) of a hook showing a fourth embodiment of the present invention. In this example, the hook 14 rotatably supported by the shaft 15 is urged by the urging force of the helical spring 40 to rotate toward the hand portion 12. That is, in FIG. 5B, the hook 14 is always subjected to the urging force of the helical spring 40 in the counterclockwise direction.

With this structure, when the robot arm is rotated to unlock the force / torque sensor, the restoring force of the helical spring 40 causes the hook 14 to bounce up and its tip to contact the hand portion 12. The position is determined, and the risk that the unexpected movement of the hook 14 may hinder the operation of other parts is eliminated.

By the way, when the force / torque sensor is locked by using the mechanism as in the third embodiment of FIG. 4, there is a possibility that the pressing force of the pin does not reach a desired value due to variations in the dimensions of parts such as the pin and the pedestal. is there. If the pressing force is insufficient, the locking becomes uncertain, while if the pressing force is excessive, the locking mechanism itself may be destroyed.

Therefore, the shaft of the roller for pressing the hook is configured to be displaceable so that the pressing force of the hook by the roller can be adjusted. Specifically, it is as follows. Figure 6
FIG. 9 is a sectional view of a roller and a roller support base showing a fifth embodiment of the present invention. In this example, the roller 38 has an eccentric shaft 42.
Is rotatably supported by the base portion of the eccentric shaft 42,
It is inserted into the roller support base 36 and receives a tightening force by the bolts 44.

According to this structure, the eccentric shaft 42 is rotated by loosening the tightening force of the bolt 44, so that the roller 38
Can be displaced in the direction A in the figure, and the hook 14
The pressing force of the roller 38 against (see FIG. 4) can be easily adjusted.

[0034]

As described above, according to the present invention,
This has the effect of preventing failure and destruction of the force / torque sensor due to vibrations at the time of launching the rocket and enabling reliable protection.

[Brief description of drawings]

FIG. 1 is a partial sectional view of a robot showing a first embodiment of the present invention.

FIG. 2 is a perspective view of a robot showing a second embodiment of the present invention.

FIG. 3 is a partial cross-sectional view near a force / torque sensor according to a second embodiment of the present invention.

FIG. 4 is a partial sectional view of a robot showing a third embodiment of the present invention.

FIG. 5 is a plan view (A) and a side view (B) of a hook showing a fourth embodiment of the present invention.

FIG. 6 is a sectional view of a roller and a roller support base showing a fifth embodiment of the present invention.

[Explanation of symbols]

 2 arm part 4 sensor housing 8 elastic body 10 sensor movable part 12 hand part 14 hook 16 pin

Claims (6)

[Claims] 1. A sensor housing (4) provided on an arm portion (2) of a robot, one end of which is supported by the sensor housing (4) through an elastic body (8), and the other end of which is mounted on the robot housing. Hand part (12)
A lock mechanism for a force / torque sensor comprising a sensor movable part (10) to which is fixed, and a means for detecting a strain generated in the elastic body (8), the sensor housing (4) and the hand part. The hook (14) swingably provided on either one of the (12), the pin (16) provided near the tip of the hook, the sensor housing (4) and the hand part (12). A pedestal that is provided on either side and on which the tip of the pin (16) sits
(18), and a lock mechanism for a force / torque sensor, characterized in that it comprises a locking means for selectively setting a state in which the tip of the pin (16) is seated on the pedestal (18) and a state not seated. . 2. The method for releasing a lock mechanism of a force / torque sensor according to claim 1, wherein the lock means is slidably provided around the sensor housing (4). Is a seat ring (30) that engages with the hook (14) while it is seated on the pedestal (18).
Including the above, by operating the robot and pressing the stop ring (30) against the metal fitting (24) on the workbench, the pin (16) is moved to the base.
A method for releasing a lock mechanism of a force / torque sensor, characterized in that the seated state in (18) is released. 3. The sensor housing (4) is rotatably provided with respect to the arm portion (2), and the locking means includes a roller support base (36) fixed to the arm portion (2), The pin (16) is rotatably provided on the roller support (36).
A force (16) according to claim 1, characterized in that it includes a roller (38) that abuts the hook (14) from the outside when (A, 16B) is seated on the pedestal (18A, 18B). Torque sensor lock mechanism. 4. The means according to claim 1, further comprising means for urging the hook (14) in a direction to release the state where the pin (16) is seated on the pedestal (18). Force / torque sensor lock mechanism. 5. The roller (38) is attached to the roller support base (36) through an eccentric shaft (42), and further comprises means for adjusting the amount of eccentricity of the eccentric shaft (42). The force / torque sensor lock mechanism according to claim 3. 6. The lock mechanism for a force / torque sensor according to claim 1, wherein the pin (16) has a substantially conical shape.