JP5093585B2 - Robot hand and gripping method - Google Patents

Description

  The present invention relates to a robot hand that holds an article.

The development of robots equipped with robot hands is advancing research and development not only for industrial use but also for various uses such as consumer use and human intervention. Such a flow is designed so that a deformed article can be grasped by one robot hand and can be used for various kinds of articles. The requirement for these robot hands is, of course, that they can be reliably grasped and released. Regarding gripping, depending on the power state of the factory, a power failure may occur during work. In such a case, it is required to prevent the gripped article from dropping. Furthermore, when gripping precision parts, some users dislike the thermal expansion of articles due to heat conduction from the robot hand. For this reason, it has been desired to prevent the robot hand from generating heat.
In a conventional hand using a spring, when a target is gripped, the target is gripped by a driving force by a motor or air, and when the target is released, the position is restored by the spring force and the target is released. There were many things (for example, refer patent document 1). In a hand using a conventional spring, the driving force is not a motor or air, but the object is gripped by the contraction force of the shape memory alloy, and when releasing the object, the link position is returned to the original position by the spring force. Is open. In the case of such a hand, it is necessary to continue supplying electric power or driving force by compressed fluid while the object is gripped.
On the other hand, there is also a hand that uses a driving force such as a motor or air to hold an object with a spring force and release the hand. In the case of such a hand, the hand is temporarily opened with a motor or air only when the object is to be gripped, held with a spring force while the object is gripped, and again when the object is released It is sufficient to temporarily open the hand with air or the like, and it is not always necessary to apply the driving force by the motor or air for a long time, thus saving energy.
Thus, a hand using a conventional spring uses a spring force for either a gripping force or an opening force.
JP 2002-321183 A (page 4, FIG. 1)

However, when there is a pattern for gripping in the direction of opening the hand and a pattern for gripping in the direction of closing the hand with the same hand, it is often necessary to use a driving force such as a motor or air as the gripping force. With such a hand, it is not possible to save energy, reduce the size of the drive device, and simplify the structure by using a spring. When a motor is used as a driving force, a certain current must continue to flow while the object is gripped, and a problem due to heat generation may occur. The motor and amplifier must be able to withstand the workload, and it is difficult to reduce the size of the drive device. When air is used as the driving force, air must be supplied for both gripping and opening, which increases the amount of air supply compared to hands that use springs for either gripping or opening force. . For example, in the case of a system that generates compressed air each time with a compressor, the number of operations of the compressor increases, which not only saves power but also suffers from compressor noise. Further, in a system for supplying compressed air from the compressed air to the tank, the frequency of filling the tank increases.
In addition, when power or air supply is cut off at the time of a power failure or the like, there is a problem that the target object is dropped and the target object is carelessly damaged.
The present invention has been made in view of such problems, and an object of the present invention is to provide a robot hand that can be securely gripped, suppresses heat generation of the robot hand, and prevents the gripped article from falling even during a power failure. And

In order to solve the above problem, the present invention is configured as follows.
The invention according to claim 1 is a base, at least one drive mechanism of a rotational drive mechanism or a linear drive mechanism provided in the base, at least one link connected to the drive mechanism, and opening of the link A first elastic member acting in a direction and a second elastic member acting in a closing direction of the link are provided in the base, and the link in which the first elastic member and the second elastic member act. A neutral region where the acting force on the link is zero, and the drive mechanism operates to a predetermined opening / closing amount when the link opens / closes, and when the article is gripped between the link and the base, The drive mechanism is not energized by being gripped by the action of one elastic member or the second elastic member .
The invention according to claim 2 is characterized in that it is gripped from the outside of the article by the elastic member and is gripped from the inside of the article by the second elastic member .
The invention according to claim 3 is characterized in that the elastic body uses at least one of a rotary spring, a linear spring, and a leaf spring .
The invention described in claim 4 is characterized in that a variable stopper is provided to adjust the action of the second elastic member .
The invention according to claim 5 includes a base, at least one drive mechanism of a rotational drive mechanism or a linear drive mechanism provided in the base, and at least one link connected to the rotational drive mechanism. The link is located in a neutral region where the acting force of the first elastic member and the second elastic member is zero in an initial state, and the link is opened and closed by the drive mechanism, and the drive mechanism opens the link. When driven in the direction, the first elastic member acts to close the link, and when the drive mechanism is driven in the link closing direction, the second elastic member acts in the link opening direction. the article gripped by said drive mechanism is configured to act against the reaction force of the first elastic member or the second elastic member does not interfere with the article To operate the link up location, the article gripped After holding the link in a position that does not the interference, it is characterized in that stops the driving force.
According to a sixth aspect of the present invention, the drive mechanism acts against a reaction force of the first elastic member or the second elastic member and does not interfere with the gripped article. The link is moved to a position, the article is released after holding the link at the position, and the link is moved to a neutral region of the first elastic member or the second elastic member. To do.

According to the present invention, when gripping an object, the robot hand can be gripped only by an elastic member in either the direction of opening the robot hand or the direction of closing the robot hand, and the driving force by the rotary drive mechanism or the linear drive mechanism grips the article. Since it is only used temporarily when it is released and released, energy can be saved, and a drive device such as a drive mechanism or a controller amplifier can be miniaturized.
In addition, since the driving force by the rotary drive mechanism or linear drive mechanism is only temporarily used when gripping and releasing the article, continuous energization is not performed, so the heat generation of the robot hand can be suppressed and precision parts The problem of heat conduction to etc. is also eliminated.
In addition, since the object is kept gripped by the spring force even when the energy is interrupted during a power failure or the like, it is possible to prevent the object from being accidentally dropped and damaged.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a first embodiment of a robot hand according to the present invention. In FIG. 1, 1 is a base, 3 is a rotation drive mechanism, 2 is a link driven by the rotation drive mechanism 3, 4 is a rotary spring acting in a direction opposite to the direction in which the hand is closed, and 5 is a direction opposite to the direction in which the hand is opened. It is a rotary spring that acts on the It is assumed that the base 1 in this embodiment also serves as a fixed link that is paired with the movable link 2.
The present invention is different from the prior art in that the spring 4 acting in the direction opposite to the direction in which the hand closes and the spring 5 acting in the direction opposite to the direction in which the hand opens are simultaneously provided.

  In FIG. 1, when the link 2 moves in the direction of closing the hand, the spring 4 is contracted soon, and a reaction force acts in the direction of opening the hand by the spring 4. On the contrary, when the link 2 moves in the direction of opening the hand, the spring 5 is contracted soon, and a reaction force acts in the direction of closing the hand by the spring 5. FIG. 9 is a graph showing this relationship. The “neutral region” in this figure is an initial position of the hand and means a region where no spring force is applied. This neutral region may have a certain width or may be completely zero. As can be seen from FIG. 9, when the hand is moved from the neutral region in the direction of closing the hand, that is, in the direction of decreasing the hand opening angle, a reaction force by the spring acts in the direction of opening the hand. In the figure, this reaction force is expressed as "opening force". On the other hand, when the hand is moved from the neutral region in the direction of opening the hand, that is, in the direction of increasing the hand opening angle, a reaction force by the spring acts in the direction of closing the hand. In the figure, this reaction force is expressed as “closing force”. In FIG. 9, the graph is simply drawn by regarding the spring constant as being constant with respect to the amount of deformation of the spring. As a specific example, when the operating range of the rotary spring in the hand of FIG. 1 is 0 ° to 20 °, if the region where the object can be gripped is set to 5 ° to 15 °, The width of the object that can be gripped is 55 to 70 mm when gripping from the outside, and 40 to 55 mm when gripping from the inside.

  FIG. 2 shows a state in which the object 7 is gripped from the outside by the hand of the first embodiment. Hereinafter, steps until the object 7 is grasped from the outside by the hand of this embodiment and released are shown. First, immediately before going to grasp the object 7, the link 2 is moved by the rotational drive mechanism 3 in the direction in which the hand opens against the spring force of the spring 5, and the hand is opened to the extent that it does not interfere with the object. Hold temporarily. Next, the object 7 is approached and stopped at a grippable position. Next, the driving force of the rotary drive mechanism 3 is stopped, and the object 7 is gripped by the spring force of the spring 5 acting in the direction of closing the hand. Next, the object 7 is moved to a predetermined position, and at the position where the object 7 is to be opened, the link 2 is moved in the direction in which the hand is opened again by the rotation drive mechanism 3 to open the object 7. When the hand has sufficiently escaped from the countermeasure 7, the driving force of the rotary drive mechanism 3 is stopped at that time, and the hand is returned to the neutral state by the spring force of the spring 5. The above is the steps until the object 7 is grasped from the outside by the hand of the first embodiment and released. Further, the state in which the object 7 is grasped in FIG. 2 corresponds to “gripping region B” in the graph of FIG. 9.

  FIG. 3 shows a state in which the object 7 is gripped from the inside by the hand of the first embodiment. Hereinafter, steps until the object 7 is grasped from the inside by the hand of the present embodiment and released are shown. First, immediately before going to grasp the object 7, the link 2 is operated against the spring force of the spring 4 in the direction in which the hand is closed by the rotational drive mechanism 3, and the hand is closed to the extent that it does not interfere with the object. Hold temporarily. Next, the object 7 is approached and stopped at a grippable position. Next, the driving force of the rotary drive mechanism 3 is stopped, and the object 7 is gripped by the spring force of the spring 4 acting in the direction of opening the hand. Next, the object 7 is moved to a predetermined position, and at the position where the object 7 is opened, the link 2 is moved again in the direction in which the hand is closed by the rotation drive mechanism 3 to open the object 7. When the hand is sufficiently escaped from the countermeasure 7, the driving force of the rotary drive mechanism 3 is stopped at that time, and the hand is returned to the neutral state by the spring force of the spring 4. The above is the steps until the object 7 is grasped from the inside by the hand of the first embodiment and released. Further, the state where the object 7 is gripped in FIG. 3 corresponds to “grip region A” in the graph of FIG. 9.

  As described above, only the spring force is acting while the object 7 is gripped, and the driving force by the rotational drive mechanism 3 is necessary when the object 7 is to be gripped and released. Just a short time. Therefore, for example, when a motor is used as the rotation drive mechanism 3, it is sufficient that a necessary torque can be instantaneously generated, and the rated torque of the motor can be reduced. Therefore, the size of the motor and the capacity of the amplifier can be reduced. Further, since it is not necessary to pass a current for a long time, heat generation is suppressed, which is advantageous in an environment where temperature control is severe. Even when the power is interrupted during a power failure, the object is held by the spring force, so that the object is not dropped and damaged.

  In the first embodiment, a rotary spring is used as the spring 4 and the spring 5, but a direct acting spring or a leaf spring may be used instead.

  FIG. 4 shows a second embodiment of the hand of the present invention. In FIG. 4, 1 is a base, 2 is three links, 6 is a linear drive mechanism that linearly drives the three links 2, 4 is a linear spring that acts in a direction opposite to the closing direction of the hand, and 5 is a hand. Is a linear spring acting in the direction opposite to the opening direction. Here, an example in which the linear drive mechanism 6 is air driven is shown. Even in the configuration of the present embodiment, the same effects as those of the first embodiment can be obtained. The details are shown below.

  FIG. 5 shows a state in which the object 7 is gripped from the outside by the hand of the second embodiment. Hereinafter, steps until the object 7 is grasped from the outside by the hand of this embodiment and released are shown. First, immediately before going to grasp the object 7, the linear drive mechanism 6 moves the link 2 in the direction in which the hand opens against the spring force of the spring 5, and opens the hand to the extent that it does not interfere with the object. Hold temporarily. Next, the object 7 is approached and stopped at a grippable position. Next, the pneumatic force of the linear drive mechanism 6 is stopped, and the object 7 is gripped by the spring force of the spring 5 acting in the direction of closing the hand. Next, the object 7 is moved to a predetermined position, and at the position where the object 7 is opened, the link 2 is moved again in the direction of opening the hand by the linear drive mechanism 6 to open the object 7. When the hand has sufficiently escaped from the countermeasure 7, the air force of the linear drive mechanism 6 is stopped at that time, and the hand is returned to the neutral state by the spring force of the spring 5. The above is the steps until the object 7 is grasped from the outside by the hand of the second embodiment and released. Further, the state where the object 7 is gripped in FIG. 5 corresponds to “grip region B” in the graph of FIG. 9.

  FIG. 6 shows a state in which the object 7 is gripped from the inside by the hand of the second embodiment. Hereinafter, steps until the object 7 is grasped from the inside by the hand of the present embodiment and released are shown. First, immediately before the object 7 is gripped, the link 2 is moved by the linear drive mechanism 6 in the direction in which the hand is closed against the spring force of the spring 4, and the hand is closed to the extent that it does not interfere with the object. Hold temporarily. Next, the object 7 is approached and stopped at a grippable position. Next, the air force of the linear drive mechanism 6 is stopped, and the object 7 is gripped by the spring force of the spring 4 acting in the direction of opening the hand. Next, the object 7 is moved to a predetermined position, and at the position where the object 7 is opened, the link 2 is moved again in the direction in which the hand is closed by the linear drive mechanism 6 to open the object 7. When the hand is sufficiently escaped from the countermeasure 7, the pneumatic force of the linear drive mechanism 6 is stopped at that time, and the hand is returned to the neutral state by the spring force of the spring 4. The above is the steps until the object 7 is grasped from the inside by the hand of the second embodiment and released. Further, the state where the object 7 is gripped in FIG. 6 corresponds to “grip region A” in the graph of FIG. 9.

In the second embodiment, compressed air is used as the driving force of the linear drive mechanism 6. Compared to the case where compressed air is used for both gripping and opening of the object, in this embodiment, compressed air is used only for the opening operation, so the consumption of compressed air is relatively small. Therefore, the energy for generating compressed air is saved. Even when the air supply is interrupted at the time of a power failure, the object is kept gripped by the spring force, so that the object is not dropped and damaged.
In the present embodiment, the article is configured to be gripped using three links. However, it is a matter of course that at least one or more links may be provided by using one of the links as a base. .

  FIG. 7 shows a third embodiment of the hand of the present invention. The configuration of the hand is almost the same as that of the first embodiment, except that three links 2 exist. In FIG. 7, the three links 2 are moved in conjunction with one rotation drive mechanism 3. FIG. 8 is a sectional view showing a state in which the object 7 is grasped with the hand of the third embodiment. As shown in FIG. 8, when the cross-sectional shape of the target object 7 is a complicated shape with many steps, the plurality of links 2 exist, so that the target object 7 can be gripped following the shape of the target object 7. FIG. 8 shows a state in which the object is gripped from the outside, but even when the shape of the inside is complicated, it can be gripped following the shape of the object 7 in the same manner.

  10 and 11 show a fourth embodiment of the present invention. The configuration of the hand is almost the same as that of the first embodiment, but the difference is that a variable stopper 8 that can adjust the range in which the spring force acts is provided. When it is desired to grip objects of different sizes with the same gripping force with the hand of the present invention, the range in which the spring force acts according to the size of the object is adjusted by adjusting the position of the spring variable stopper 8. Can be adjusted freely. The hand in FIG. 10 and the hand in FIG. 11 are the same hand, but the range in which the spring force of the rotary spring 5 acts is changed by changing the position of the variable stopper 8. Although the size of the object 7 is different between FIG. 10 and FIG. 11, the gripping force acting on the object 7 is the same. 10 and 11 show only the variable stopper 8 for the rotary spring 5, but if the variable stopper for the rotary spring 4 is provided in the same manner, the same effect can be obtained when the object 7 is gripped from the inside. Can be obtained.

  FIG. 12 shows a fifth embodiment of the hand of the present invention. The configuration of the hand is almost the same as in the second embodiment, but the difference is that it has a mechanism that can increase or decrease the number of linear springs 4 and linear springs 5. In FIG. 12, the number of springs is doubled with respect to FIG. As a result, the gripping force due to the spring force is doubled. In FIG. 12, 9 is a linear spring guide. If a plurality of linear spring guides 9 are provided in advance, the number of linear springs 4 and linear springs 5 can be increased or decreased according to the required gripping force to adjust the gripping force. The adjustment method of the gripping force by the spring is not limited to the increase or decrease of the number of springs. Even if only one linear spring guide 9 exists, if the linear spring 4 and the linear spring 5 are configured to be easily exchangeable, by changing the wire diameters of the linear spring 4 and the linear spring 5, The gripping force by the spring can also be adjusted.

The front view of the hand which shows 1st Example of this invention The front view showing the state which hold | gripped the target object from the outer side with the hand of 1st Example of this invention. The front view showing the state which hold | gripped the target object from the inside with the hand of 1st Example of this invention. Front view and side view of a hand showing a second embodiment of the present invention The front view showing the state which grasped the subject from the outside with the hand of the 2nd example of the present invention. The front view showing the state which hold | gripped the target object from the inside with the hand of 2nd Example of this invention. Front view and side view of a hand showing a third embodiment of the present invention The upper sectional view showing the state where the object was grasped with the hand of the 3rd example of the present invention. The graph showing the relationship between the opening angle of the hand of the present invention and the gripping force by the spring The front view showing the state which hold | gripped the target object with the hand of 4th Example of this invention. The front view showing the state which hold | gripped the target object with the hand of 4th Example of this invention. Side view of the hand showing the fifth embodiment of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base part 2 Link 3 Rotation drive mechanism 4 Spring 5 Spring 6 Linear drive mechanism 7 Target object 8 Variable stopper 9 Guide for linear springs

Claims (6)

A base, at least one drive mechanism of a rotational drive mechanism or a linear drive mechanism provided in the base, at least one link coupled to the drive mechanism, and a first elasticity acting in the opening direction of the link A member and a second elastic member acting in the closing direction of the link are provided on the base,
A neutral region where the acting force on the link on which the first elastic member and the second elastic member act is zero;
When the link opens and closes, the drive mechanism works to a predetermined opening and closing amount,
A robot hand characterized in that when the article is gripped between the link and the base, it is gripped by the action of the first elastic member or the second elastic member and the drive mechanism is not energized. . The robot hand according to claim 1, wherein the robot hand is gripped from the outside of the article by the first elastic member, and is gripped from the inside of the article by the second elastic member. The robot hand according to claim 1, wherein the elastic body uses at least one of a rotary spring, a linear spring, and a leaf spring. The robot hand according to any one of claims 1 to 3, wherein a variable stopper is provided to adjust an action of the second elastic member. A base, a rotational drive mechanism or a linear drive mechanism provided in the base, and at least one link coupled to the rotational drive mechanism; Located in the neutral region where the acting force of the elastic member and the second elastic member is zero,
The link is opened and closed by the drive mechanism, and when the drive mechanism is driven in the opening direction of the link, the first elastic member acts to close the link, and the drive mechanism is moved in the closing direction of the link. When the second elastic member is actuated in the direction of opening of the link when driven, the article is gripped,
The drive mechanism acts against the reaction force of the first elastic member or the second elastic member, operates the link to a position where it does not interfere with the article, and holds the link at the position where the interference does not occur Then, the robot hand is gripped by gripping the article and stopping the driving force . The drive mechanism operates against the reaction force of the first elastic member or the second elastic member and operates the link to a position where it does not interfere with the article that has been gripped. The robot hand according to claim 5, wherein the article is released after the link is held, and the link is moved to a neutral region of the first elastic member or the second elastic member. Method.

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