JP2015020246A - Object holding method and contact mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold a fragile object, a ductile object and a heavy object with one holding device.SOLUTION: An object holding method in a holding device 200 which includes a contact mechanism 100 having a contact member 101, a charging member 104 charged in the contact member 101 and having fluidity, charging pressure adjustment means 105 adjusting the charging pressure and charging pressure detection means 141 detecting the charging pressure, and holds an object 300 by bringing the contact mechanism 100 into contact with the object, includes: a preparation step for making the charging pressure in the contact member 101 the first charging pressure; a pressing force increase step for gradually increasing pressing force on the object 300 of the contact member 101; a specific charging pressure detection step for detecting specific charging pressure which is the charging pressure in a case in which the charging pressure is not increased even though the pressing force increase step is executed; and a holding step for holding the object 300 at the specific charging pressure or pressure less than the specific charging pressure but near the specific charging pressure.

Description

  The present invention relates to an object holding method in an abutment mechanism that is attached to a clamping device (manipulator, gripper) for holding and holding an object and that directly lifts or transfers the object, and the contact In particular, the present invention relates to an object holding method for holding a wide variety of objects and the contact mechanism.

  In recent years, robots capable of holding various kinds of objects have appeared. For example, Patent Document 1 describes a technique related to a robot hand that can hold an object having various shapes. Specifically, the robot hand described in Patent Document 1 includes a contact member that directly contacts an object. The contact member is a bag-shaped member containing powder, and the contact member can be flexibly applied to objects of various shapes by supplying and discharging an appropriate amount of powder filled in the contact member. Correspondingly, a technique for stably holding the robot hand is described.

JP 2002-370188 A

  However, for example, a robot that performs various tasks in daily life is not only required to hold a strong object as described in Patent Document 1, but also a brittle object that is brittle and fragile, and stretched and fragile. It is required that various objects such as ductile objects and heavy objects can be held by a single robot.

  The present invention has been made in view of the above problems, and provides an object holding method capable of holding an object such as a brittle object or a ductile object without replacing the contact mechanism attached to the holding device, and It is an object of the present invention to provide a contact mechanism that can hold an object such as a brittle object or a ductile object and can also hold a heavy object.

  In order to achieve the above object, an object holding method according to the present invention includes a bag-like contact member that comes into contact with an object to be held, and a fluid filling that fills the inside of the contact member. A contact mechanism comprising: a member; a filling pressure adjusting means for adjusting a filling pressure that is a pressure of the filling member in the contact member; and a filling pressure detecting means for detecting the filling pressure of the filling member. An object holding method in a holding device that holds an object by bringing the contact mechanism into contact with an object, wherein the filling pressure in the contact member is set to a first filling pressure by the filling pressure adjusting means And a step of increasing the pressing force and a step of increasing the pressing force by causing the contact member that has reached the first filling pressure to contact the object and gradually increasing the pressing force of the contact member against the object. I'm doing Regardless of the specific filling pressure, the specific filling pressure detecting step for detecting the specific filling pressure, which is a filling pressure when no increase in the filling pressure is recognized, A holding step of holding the object at a pressure of.

  According to this, by holding the object under the specific filling pressure or less than the specific filling pressure, even if the object is a brittle object or a ductile object, the object can be held without being destroyed. It becomes like this.

  Moreover, it is preferable to gradually increase the pressing force by moving the contact member gradually in the direction of the object.

  According to this, it is possible to control the increase in the pressing force more accurately, and it is possible to increase the detection accuracy of the specific filling pressure.

  Also, if the specific filling pressure is the pressure when the filling pressure is constant despite the increase of the pressing force, it can be determined that the object being held is a ductile object, and the specific filling pressure has been reached It is possible to hold the object even if it is left as it is.

  In addition, when the specific filling pressure is the peak pressure when the filling pressure decreases despite the increase in the pressing force, it can be determined that the object to be held is a brittle object, and the same kind of object is At the time of holding, the object can be held at a specific filling pressure or a pressure lower than the specific filling pressure and near the specific filling pressure.

  In order to achieve the above object, a contact mechanism according to the present invention is a contact mechanism that is attached to a holding device that holds an object and contacts the object, and includes a bag-shaped contact member and A fluid-filling member filled in the contact member and a reinforcing member disposed in a state of being covered with the contact member and having rigidity higher than that of the contact member filled with the filler member It is characterized by comprising a member and a filling pressure adjusting means for adjusting a filling pressure which is a pressure in the contact member of the filling member.

  According to this, even if it is a heavy object that cannot be lifted simply by pressing the contact member filled with the filling member against the object, the reinforcing member disposed inside the contact member is interposed via the contact member. The object can be lifted by pressing it against the object.

  Furthermore, you may provide the filling pressure detection means which detects the filling pressure of the said filling member.

  According to this, it is possible to hold the object such as a brittle object or a ductile object by performing the object holding method, and it is also possible to hold a heavy object by the reinforcing member.

  The reinforcing member may include a dome-shaped surface portion on the contact member side.

  According to this, the contact member can be pressed against the object without being damaged by the reinforcing member. Further, by reducing the contact area between the object and the abutting member, the pressing force of the clamping device can be effectively used as the holding force.

Further, the reinforcing member has a cavity therein, and further, a second filling member that is filled in the cavity, and a second filling pressure adjusting unit that adjusts a second filling pressure that is a pressure of the second filling member. You may prepare.

  According to this, the rigidity (softness) of the entire reinforcing member filled with the second filling member can be adjusted and adjusted by adjusting the pressure of the second filling member filled in the cavity of the reinforcing member. It becomes possible to further increase variations of objects that can be performed.

  In addition, implementing the program for making a computer perform each process which the said object holding method contains also corresponds to implementation of this invention. Of course, implementing the recording medium in which the program is recorded also corresponds to the implementation of the present invention.

  It is possible to hold a brittle object, a ductile object, and a heavy object without replacing the holding mechanism attached to the holding device.

FIG. 1 is a perspective view schematically showing a clamping device to which a contact mechanism is attached. FIG. 2 is a perspective view showing the contact mechanism in cross section. FIG. 3 is a block diagram showing the functional unit of the clamping device together with the mechanism unit. FIG. 4 is a flowchart showing the flow of the object processing method. FIG. 5 is a graph showing the relationship between the pressing force and the filling pressure when a specific filling pressure is generated. FIG. 6 is a graph showing the relationship between the pressing force and the filling pressure when a specific filling pressure is generated in another pattern. FIG. 7 is a perspective view showing another embodiment of the contact mechanism in cross section.

  Next, embodiments of the object holding method and the contact mechanism according to the present invention will be described with reference to the drawings. The following embodiments are merely examples of the object holding method and the contact mechanism according to the present invention. Accordingly, the scope of the present invention is defined by the wording of the claims with reference to the following embodiments, and is not limited to the following embodiments. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept of the present invention are not necessarily required to achieve the object of the present invention. It will be described as constituting a preferred form.

  FIG. 1 is a perspective view schematically showing a clamping device to which a contact mechanism is attached.

  As shown in the figure, the holding device 200 is a mechanism that is attached to, for example, the tip of a robot hand and holds an object 300. The clamping device 200 includes a contact mechanism 100, finger portions 201, and a clamping drive source 202. In the case of the present embodiment, the clamping device 200 can open and close with one degree of freedom.

  The finger part 201 is a mechanism that transmits the driving force generated by the clamping drive source 202 to the contact mechanism 100. In the case of this embodiment, a parallel crank mechanism is employed for the finger portion 201. As a result, when the object 300 is clamped, the abutment mechanism 100 can be moved while maintaining parallel to the clamping drive source 202, and the direction of the pressing force against the object 300 (X-axis direction in the figure) can be changed. It becomes possible to make it constant.

  In the present embodiment, the sandwiching device 200 includes two finger portions 201. However, the sandwiching device 200 includes a fixed portion that is fixed to the sandwiching drive source 202 and a contact mechanism with respect to the fixed portion. One finger part 201 for advancing and retracting 100 may be provided, or three or more finger parts 201 may be provided to separate the contact mechanism 100.

  The clamping drive source 202 is a part that generates a clamping force in the clamping device 200. In the case of the present embodiment, the sandwiching drive source 202 includes a housing 203 and a motor (not shown). The motor can control the amount of movement of the contact mechanism 100 by detecting the rotation angle with an attached encoder. As a result, the pressing force against the object 300 can be gradually increased.

  FIG. 2 is a perspective view showing the contact mechanism in cross section.

  As shown in the figure, the abutment mechanism 100 is a mechanism that is attached to the clamping device 200 and abuts on the object 300, and can change the rigidity of the portion that abuts directly on the object 300. The contact mechanism 100 includes a contact member 101, a reinforcing member 103, a filling member 104, and a filling pressure adjusting unit 105. In the case of the present embodiment, the contact mechanism 100 includes a base body 102 and a filling pressure detection means 141.

  The abutting member 101 is a portion that directly abuts on the object 300 when the clamping device 200 clamps the object 300, and is a bag having a flexible (stretchable) sheet. Although the material of the contact member 101 is not particularly limited, rubber having a high frictional force with the object 300 can be exemplified.

  In the case of the present embodiment, the contact member 101 has a hemispherical appearance or a dome shape having a shape similar to this, and the contact member 101 is 1 mm or less (specifically, about 100 μm). Thick nitrile rubber is used. The opening 111 of the contact member 101 is circular, and the opening 111 is connected to the base body 102. Note that the shape of the opening 111 is not limited to a circle, and an arbitrary shape such as a rectangle can be adopted.

  The reinforcing member 103 is a member that is pressed against the object 300 with the abutting member 101 sandwiched between the abutting member 101 and the abutting member 101 when only the abutting member 101 filled with the filling member 104 cannot hold the object 300. It is arranged in a state of being covered with the member 101 and has higher rigidity than the contact member 101.

  Here, the rigidity higher than the contact member 101 used in the present specification and claims means that the rigidity of the material constituting the contact member 101 is compared with the rigidity of the material constituting the reinforcing member 103. Instead, when the filling member 104 is filled in the hollow bag-shaped contact member 101, the reinforcing member is used against the deformation amount of the contact member 101 when a predetermined pressure is applied to the contact member 101 from the outside. When the deformation amount of the reinforcing member 103 when the same pressure is directly applied to 103 is small, it is expressed that the rigidity of the reinforcing member 103 is higher than that of the contact member 101. The same applies to the case where the second filling member 142 is filled into the reinforcing member 103 described later, and the filling member 104 is filled into the reinforcing member 103 filled with the second filling member 142 under the same pressure as the filling member 104. When the deformation amount of the reinforcing member 103 is small when the same pressure as the pressure applied to the abutting member 101 is applied, the rigidity of the reinforcing member 103 is expressed as higher than that of the abutting member 101.

  In the case of the present embodiment, the reinforcing member 103 includes a dome-shaped surface portion 131 on the abutting member 101 side. Specifically, the reinforcing member 103 has a solid hemisphere or a shape similar thereto. . The material constituting the reinforcing member 103 is silicon rubber. The reinforcing member 103 is disposed concentrically with the contact member 101 and is fixed to the base body 102.

  The reinforcing member 103 is not limited to the present embodiment. For example, the material may be a resin other than rubber, or may be a metal. The shape of the reinforcing member 103 does not need to have a smooth surface, and may include a plurality of protrusions protruding radially outward on the surface.

  The filling member 104 is a substance having fluidity that is filled between the contact member 101 and the reinforcing member 103. The filling member 104 is preferably an incompressible fluid. Here, the incompressible rectifier is a fluid (a fluid that does not shrink) so small that a change in density due to pressure or temperature can be ignored. Specifically, the filling member 104 may be a liquid having a higher viscosity than water, a gel-like substance, a powder, or the like, and is not necessarily an ideal incompressible rectifier or a fluid close thereto. The description does not deny water or gas as the filling member 104.

  The filling pressure adjusting means 105 is a device that adjusts the filling pressure that is the pressure of the filling member 104 in the contact member 101. In the case of the present embodiment, the filling pressure adjusting means 105 is a syringe pump and is connected to a tube member (not shown) connected to the first opening 121 of the base body 102. The filling pressure adjusting means 105 includes a syringe and a piston that slides relative to the syringe, and the piston can reciprocate with respect to the syringe by a motor. The filling pressure adjusting means 105 can raise the pressure of the filling member 104 in the contact member 101 by pushing out the piston, and can lower the pressure of the filling member 104 in the contact member 101 by pulling back the piston. It has become a thing.

  The base 102 is a structural member that holds the opening 111 of the contact member 101 so as to close the opening of the contact member 101, and the base 102 is attached to the finger portion 201. In the case of the present embodiment, the base body 102 is a cylindrical member whose both ends are closed, and a first opening 121 through which the filling member 104 is circulated is connected to the filling pressure adjusting means 105 at one end portion. A second opening 122 communicating with the inside of the contact member 101 is provided at the other end.

  The filling pressure detection unit 141 is a device that detects the filling pressure of the filling member 104 filled in the contact member 101. In the case of the present embodiment, the filling pressure detection means 141 is a pressure sensor and is disposed inside the hollow base body 102. As a result, the filling pressure of the filling member 104 adjusted by the filling pressure adjusting means 105 can be directly detected.

  The filling pressure detection means 141 is not limited to a pressure sensor, and any pressure detection method can be adopted. For example, a device that detects the relative movement amount of the piston with respect to the syringe of the syringe pump may be used as the filling pressure detection means 141.

  Next, the object holding method will be described.

  FIG. 3 is a block diagram showing the functional unit of the clamping device together with the mechanism unit.

  As shown in the figure, the clamping device 200 includes a clamping control device 206. The sandwiching control device 206 is a computer, and controls the mechanical unit of the sandwiching device 200 by executing each processing unit configured by software. The sandwiching control device 206 includes a pressing force adjusting unit 261, a sandwiching state determining unit 264, a filling pressure adjusting unit control unit 162, and a filling pressure detecting unit 163 as functional units.

  The pressing force adjustment unit 261 is a processing unit that controls the motor of the clamping drive source 202 and controls the rotation angle of the motor based on a signal from an encoder attached to the motor. The pressing force adjusting unit 261 controls the amount of movement of the contact mechanism 100 by controlling the clamping drive source 202, for example, by moving the contact mechanism 100 gradually in the direction of the object 300. The pressing force of the member 101 can be gradually increased.

  The filling pressure adjustment unit control unit 162 and the filling pressure detection unit 163 are processing units that control the filling pressure adjustment unit 105. The filling pressure detection unit 163 is a processing unit that converts the signal acquired from the filling pressure detection unit 141 and transmits the signal to the filling pressure adjustment unit control unit 162. The filling pressure adjustment unit control unit 162 receives the signal from the filling pressure detection unit 163. Is a processing unit that feedback-controls the filling pressure adjusting means 105 based on the above signal. By these processing units, the filling pressure of the filling member 104 in the contact member 101 can be set to a predetermined value.

  The clamping state determination unit 264 detects the specific filling pressure based on the signal from the pressing force adjustment unit 261 and the signal from the filling pressure detection unit 163, and is less than the specific filling pressure or the specific filling pressure, It is a processing unit that determines the filling pressure for holding the object 300. The filling pressure that is lower than the specific filling pressure and can hold the object 300 may be determined by holding the same kind of object 300 a plurality of times, and is a numerical value such as 90% or more of the specific filling pressure. You may choose based on a certain threshold. Further, the clamping state determination unit 264 may determine the position (gripping state) of the finger unit 201 and adjust the filling pressure adjustment unit control unit 162.

  FIG. 4 is a flowchart showing the flow of the object processing method.

  First, before the object 300 is sandwiched, that is, before the abutting member 101 is brought into contact with the object 300, the filling pressure adjusting unit control unit 162 and the filling pressure detecting unit 163 function to fill the filling pressure adjusting unit 105. Thus, the filling pressure of the filling member 104 in the contact member 101 is adjusted to the first filling pressure (S101, preparation step). In the preparation step S101, the filling pressure detecting unit 163 is not functioned, and the filling pressure adjusting unit control unit 162 is functioned to set the filling pressure adjusting unit 105 to a predetermined state (for example, the same state as the previous time). The pressure may be adjusted to the first filling pressure.

  Next, the pressing force adjusting unit 261 is caused to function to control the nipping drive source 202 so that the contact member 101 whose pressure of the filling member 104 becomes the first filling pressure is brought into contact with the object 300, so that the contact member 101. The pressing force against the object 300 is gradually increased (S102, pressing force increasing step). In the pressing force increasing step S102, it is considered that the pressing force is gradually increased by causing the filling pressure adjusting means 105 to gradually increase the filling pressure after the contact member 101 is brought into contact with the object 300. It is done.

  Here, while executing the pressing force increasing step S102, the filling pressure adjusting unit control unit 162 performs the feedback control based on the information from the filling pressure detection unit 163, and performs the first filling pressure and the first filling pressure in the preparation step S101. The filling pressure adjusting means 105 is controlled so as to maintain this state.

  Next, if the increase in the filling pressure is not recognized despite the execution of the pushing force increasing step S102, the holding state is based on the signal from the pushing force adjusting unit 261 and the signal from the filling pressure detecting unit 163. When the determination unit 264 determines (S103: Y), the sandwiching state determination unit 264 detects the filling pressure at the time of the determination as the specific filling pressure, and the specific filling pressure is less than the specific filling pressure or the specific filling pressure. A holding state in which the object 300 is held with a nearby pressure is determined (S104, holding state determining step).

  Finally, the object 300 is held based on the determined holding state (determined by the pressing force and the filling pressure) (holding step). If the object 300 has almost the same type, for example, weight, shape, brittleness, and ductility, the object 300 can be held in the same holding state.

  Next, the specific filling pressure will be described.

  FIG. 5 is a graph showing the relationship between the pressing force and the filling pressure when a specific filling pressure is generated.

  As shown in the figure, when the filling pressure is constant (the portion indicated by SP1 in the figure) despite the increase of the pressing force, the pressure is a specific filling pressure. Here, the constant filling pressure indicates a state in which the rising angle of the graph is gentler than the graph showing the relationship between the pressing force and the filling pressure when holding the object 300 made of a rigid body. Even in a portion where the filling pressure is slightly increased, such as a portion indicated as SP1 in the same figure, the rising angle is loose with respect to the entire scale, so the filling pressure corresponds to a constant value.

  In this case, if the object 300 is held when the filling pressure in the contact member 101 becomes the specific filling pressure (holding point in the figure), the same type of object 300 can be held with good reproducibility. It becomes.

  FIG. 6 is a graph showing the relationship between the pressing force and the filling pressure when a specific filling pressure is generated in another pattern.

  As shown in the figure, when the filling pressure is lowered despite the increase of the pressing force, the peak pressure (portion indicated by SP2 in the figure) is the specific filling pressure.

  In this case, if the object 300 is held when the filling pressure in the contact member 101 becomes about 90% or more of the specific filling pressure (holding point in the figure), the same type of vulnerable object 300 can be held without being destroyed and can be reproduced.

  In addition, this invention is not limited to the said embodiment. For example, another embodiment realized by arbitrarily combining the components described in this specification and excluding some of the components may be used as an embodiment of the present invention. In addition, the present invention includes modifications obtained by making various modifications conceivable by those skilled in the art without departing from the gist of the present invention, that is, the meaning described in the claims. It is.

  For example, as shown in FIG. 7, the reinforcing member 103 may include a cavity 132 therein, and the contact mechanism 100 further includes a second filling member 142 and a second filling member 142 that are filled in the cavity 132. You may provide the 2nd filling pressure adjustment means 152 which adjusts the 2nd filling pressure which is a pressure.

  Thereby, the rigidity of the reinforcing member 103 can be adjusted by the filling pressure of the second filling member 142, and the holding state for holding the object 300 can be adjusted more finely.

  Further, the filling pressure detection means 141 may be disposed inside the contact member 101, and the second filling pressure detection means 143 detects the second filling pressure inside the cavity 132 of the reinforcing member 103. May be provided.

  The present invention can be used for a holding device that can hold a plurality of types of objects for general use. For example, the holding device is attached to the tip of a robot hand to lift or transfer an object. Available to the device.

100 Contact Mechanism 101 Contact Member 102 Base 103 Reinforcing Member 104 Filling Member 105 Filling Pressure Adjusting Means 111 Opening 121 First Opening 122 Second Opening 131 Surface Part 132 Cavity 141 Filling Pressure Detection Means 142 Second Filling Member 143 Second filling pressure detecting means 152 Second filling pressure adjusting means 162 Filling pressure adjusting means control unit 163 Filling pressure detecting unit 200 Nipping device 201 Finger unit 202 Nipping drive source 203 Housing 206 Nipping control device 261 Pushing force adjusting unit 264 Holding state Decision unit 300

Claims (8)

A bag-shaped contact member that contacts an object to be held, a fluid-filling member that fills the inside of the contact member, and a filling pressure that is a pressure of the filling member in the contact member A holding device comprising a contact mechanism including a filling pressure adjusting means for adjusting the filling pressure and a filling pressure detecting means for detecting a filling pressure of the filling member, and holding the object by contacting the contact mechanism with the object An object holding method in
A preparation step of setting the filling pressure in the abutment member to the first filling pressure by the filling pressure adjusting means;
A pressing force increasing step of bringing the abutting member having the first filling pressure into contact with an object and gradually increasing the pressing force of the abutting member against the object;
A specific filling pressure detecting step for detecting a specific filling pressure, which is a filling pressure when no increase in the filling pressure is recognized despite the execution of the pressing force increasing step;
A holding step of holding the object at a pressure that is less than the specific filling pressure or near the specific filling pressure. The object holding method according to claim 1, wherein the pressing force is gradually increased by gradually moving the contact member in the direction of the object. The object holding method according to claim 1 or 2, wherein the specific filling pressure is a pressure when the filling pressure is constant despite an increase in pressing force. 3. The object holding method according to claim 1, wherein the specific filling pressure is a peak pressure when the filling pressure decreases despite an increase in pressing force. 4. A contact mechanism that is attached to a clamping device that sandwiches an object and contacts the object,
A bag-shaped contact member;
A filling member having fluidity filled in the contact member;
A reinforcing member that is disposed in a state of being covered by the contact member and has a rigidity higher than that of the contact member filled with the filling member;
A contact mechanism comprising: a filling pressure adjusting means for adjusting a filling pressure which is a pressure in the contact member of the filling member. further,
The contact mechanism according to claim 5, further comprising a filling pressure detecting means for detecting a filling pressure of the filling member. The abutment mechanism according to claim 5, wherein the reinforcing member includes a dome-shaped surface portion on the abutment member side. The reinforcing member includes a cavity inside,
further,
A second filling member filling the cavity;
The contact mechanism according to claim 5, further comprising a second filling pressure adjusting unit that adjusts a second filling pressure that is a pressure of the second filling member.

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