JP2710836B2 - Hand device for gripping parts - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a component gripping hand device for gripping a component to be assembled in a component assembling operation.

2. Description of the Related Art Conventionally, in a part assembling operation, as a hand device for gripping a component to be assembled, a dedicated hand device is prepared in advance according to the shape of each component, and a component to be gripped is prepared. Each time is changed, the hand device is set to be changed.

For example, in the case where the component has a round shape, there is a collect check conventionally, and it is possible to grip almost any round member regardless of its size as long as the shape is a round shape. On the other hand, a hand device that has two finger members, and grips a component by sandwiching the component from both sides with these finger members is also conventionally known.

[Problems to be Solved by the Invention] However, in the hand device of the conventional configuration, since it is configured as a dedicated hand device for each shape, it is possible to hold the target shape regardless of its size, regardless of its size. However, if it is not the desired shape, it cannot be gripped well and various hand devices must be provided, which is a problem in terms of cost and space.

The prior art relating to the present invention, in particular, an apparatus for gripping articles by providing three fingers and driving the three fingers by a drive shaft is disclosed in Japanese Patent Application Laid-Open No. Sho 57-1686 and Japanese Utility Model Application Laid-Open No. Sho 60-74985. A gazette is known.

Japanese Patent Application Laid-Open No. 61-33883 discloses a robot gripping device for automatically gripping an object or a work piece, which can be selectively rotated in one direction and the opposite direction, and serves as an output drive member. And a plurality of gripper assemblies that can be driven by the output drive member, wherein each gripper assembly is secured to a shaft and has a rotatable shaft that has a lever that projects laterally from the shaft. A gripper assembly having gripper / finger means protruding laterally from the end of the shaft, a coupling means intermediate the shaft of the gripper / assembly and the output drive member, and controlling the coupling means to at least all of Until the gripper finger contacts the object, the output member is connected to the gripper via the connecting means. Limiting the torque transmitted to the shaft of the rippa assembly to a relatively low value, after the gripper finger contacts the object,
A gripping device is disclosed which comprises at least means for changing the torque to a relatively high torque suitable for handling an object without causing a slip.

The present invention has been made in view of the above problems,
An object of the present invention is to provide only one hand device,
An object of the present invention is to provide a component gripping hand device that can reliably grip components having various shapes.

Another object of the present invention is to have at least three fingers for gripping an article,
An object of the present invention is to provide an article gripping hand device that includes independent driving means for each finger so that the moving directions can be different from each other, and further allows each driving means to perform an operation corresponding to an article.

Another object of the present invention is to fix a first arm to each of three independently rotating shafts, attach a finger for gripping an article to each first arm, and attach a finger to each of the fingers. An object of the present invention is to provide an article gripping hand device in which a second finger that expands and contracts can be provided.

Still another object of the present invention is to provide a hand device in which at least three fingers to which driving force is applied by a driving means, for example, a motor, have members. An object of the present invention is to provide a gripping hand device.

Still another object of the present invention is to output a signal for gripping an article by a finger member, and to use the gripping signal to move to the next step. It is to provide a device.

[Means for Solving the Problems] In order to solve the above-mentioned problems and achieve the object, an article gripping hand device according to the present invention includes a hand body, and at least three shafts attached to the hand body. When,
Rotating means for rotating the respective shafts, first arms attached to the respective shafts, fingers provided on the respective first arms for gripping the articles, and the fingers gripping the articles. Control means for controlling the rotation of the first arm, the control means for defining the rotation direction and the rotation angle of the rotation means, and the control means for controlling the rotation direction and rotation of the rotation means. And teaching means for teaching the corners.

[Embodiment] Hereinafter, the configuration of an embodiment of a component gripping hand device according to the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the hand device 10 of this embodiment is
Is attached to a robot arm 12 (not shown), and has an attachment member 14 detachably attached to the tip of the robot arm 12. A hand main body 18 is connected to the mounting member 14 via a connection rod 16 extending along the vertical direction.

Here, the hand main body 18 is formed from a flat plate whose planar shape is set to a substantially triangular shape, and each corner has a reversible rotatable servomotor 20a, 20b, 20
c is provided. In other words, the three servo motors 20a, 20b, 20
Output shafts 24a, 24b and 24c of c are provided. The lower end of the connection rod 16 is set to be connected at the center of gravity of the hand body 18.

Each of the servomotors 20a, 20b, 20c has a drive shaft (not shown) extending in the vertical direction, and a lower end of each drive shaft is connected to a speed reduction mechanism 22a, 22b, 22c. The lower ends of the output shafts 24a, 24b, 24c of the speed reduction mechanisms 22a, 22b, 22c penetrate the hand body 18 and extend downward therefrom. on the other hand,
The upper end of each drive shaft has a corresponding servo motor 20a, 20b, 20c
And encoders 26a, 26b, 26c for detecting the respective amounts of rotation are connected to the respective upper ends.

At the lower end of each output shaft 24a, 24b, 24c, a mounting plate 28a, 2
8b and 28c are fixed, and finger attachment plates 30a, 30b and 30c are detachably connected to one outer edge of each of the attachment plates 28a, 28b and 28c. The mounting plates 28 connected to each other
a, 28b, 28c and fingers attached plate 30a, 30b, and 30c, each of the servo motors 20a, 20b, the first arm L ₁ which issued along connexion extending from the rotation center of 20c in the radial direction, L _2, L ₃ Are configured respectively.

Here, on the upper surface of each finger attachment plate 30a, 30b, 30c,
Drive cylinder mechanism 32 driven by compressed air as a drive source
a, 32b, 32c are attached, and pistons (third arms) 34a, 34b, 34c, which are driven to expand and contract by the piston operations of the drive cylinder mechanisms 32a, 32b, 32c, can move forward and backward along the vertical direction. And is taken out downward while penetrating the corresponding finger attachment plates 30a, 30b, 30c.

On the other hand, on the lower surface of each finger attachment plate 30a, 30b, 30c, a fixed first finger member (second
Arm) 36a, 36b, 36c corresponds to the drive cylinder mechanism 32
It is fixed coaxially with a, 32b, 32c. Here, the lower ends of the pistons 34a, 34b, 34c are connected to the corresponding first finger members 3
6a, 36b, and 36c, the first finger members 36a, 36b, and 36c extend below the lower ends of the first finger members 36a, 36b, and 36c to form a movable second finger member. doing.

The movable second finger members 34a, 34b, 34c are driven by being drawn in by introducing compressed air into one of the input ports of the corresponding drive cylinder mechanisms 32a, 32b, 32c. It is set so as to be drawn into one finger member 36a, 36b, 36c. On the other hand, each movable second finger member 34a, 34b, 34c is driven to be pushed out by introducing compressed air into the other input port of the corresponding drive cylinder mechanism 32a, 32b, 32c, and the corresponding first finger member is driven. The finger members 36a, 36b, 36c are set so as to be taken out downward.

As is clear from the above description, the movable second finger members 34a, 34b, 34c are set to have smaller diameters than the first finger members 36a, 36b, 36c.

Here, as shown in FIG.
a, 20b, 20c of the distance between the center of rotation of each other and _{l 1, l 2, l 3} ,
The servo motors 20a, 20b, the first arm L _1, L _2, L ₃ which is attached to 20c, the corresponding servo motor 20a, 20b,
Rotation center and the drive cylinder mechanism 32a of 20c, 32 b, the distance between the 32c of the drive shaft, i.e., the r _1, r _2, r ₃ and operation radius of each first arm L _1, L _2, L ₃ Then, these l ₁ , l ₂ , l ₃ and r ₁ , r ₂ ,
The following relationship is defined between r ₃ and r ₃ . That is, r ₁ <min (l ₁ , l ₃ ) r ₂ <min (l ₁ , l ₂ ) r ₃ <min (l ₂ , l ₃ ) where min (a, b) is a plurality of numerical values a , b is defined as a function indicating that it takes the minimum value.

From this relationship, the radius r of the first arm L attached to one servomotor is set to a value smaller than the shorter distance l of the distances l to the rotation centers of the other two servomotors. Will be done. In other words, each first arm L ₁ , L ₂ , L ₃ is set to be able to freely rotate 360 degrees around its own rotation center, and as a result, each first finger member 36a, 36b and 36c can freely turn on the circumferences of the radii r ₁ , r ₂ and r ₃ respectively.

The radii r ₁ , r ₂ , and r 1 of the first arms L ₁ , L ₂ , and L ₃ , respectively.
r ₃ can be freely set by setting the lengths of the finger attachment plates 30a, 30b, 30c to different lengths.

On the other hand, as shown in FIG. 3, each of the servomotors 20a, 20b,
Motor drivers 38a, 38b, 38c are connected to 20c, respectively, and the respective servo motors 20a, 20b, 20c are set to be drive-controlled based on drive signals from these motor drivers 38a, 38b, 38c. I have.

In addition, the driving state of each servomotor 20a, 20b, 20c, that is, the encoder 26a that detects the rotation amount of the corresponding drive shaft,
26b, 26c are connected to the position detection circuits 40a, 40b, 40c, respectively, and each of the position detection circuits 40a, 40b, 40c, based on the detection signal from the corresponding encoder 26a, 26b, 26c, The rotation angles of the _first arm L ₁ , L ₂ , L ₃ are set to be accurately detected.

These motor drivers 38a, 38b, 38c and the position detection circuit 4
0a, 40b, and 40c are NC control units 42 that control the entire control operation.
The control unit 42 is connected to a teaching unit 44 for teaching and storing the operation procedure of the finger in advance. Here, this control unit 42
In accordance with what is taught and stored in this Teichingu Units - 44, each of the first current while detecting the angular position of the arm L _1, L _2, L _3, a first finger member of the three work of a predetermined shape Each motor driver 3 to hold by 36a, 36b, 36c
8a, 38b, 38c are set to output control signals.

As shown in FIG. 3, the control unit 42 is further connected to an energization time setting circuit 46 and a back electromotive force detection circuit 48.

Here, the energization time setting circuit 46, in order to grip the article W _A, the first arm L _1, L _2, L ₃ servo motor 20a to rotate from the initial position, 20b, 20c of each of the The motor coil (not shown) is configured so that the energization time is set to only a predetermined time. Note that this predetermined time is determined by the first arm L ₁ ,
When L _2, L ₃ has along connexion rotated clockwise from the initial position, corresponding first finger members 36a, 36b, 36c is in contact with the outer peripheral surface of the workpiece W _A, further, the outer peripheral surface from contact with the presses inwardly, each of the first finger members 36a, 36b, 36c by until the pressing force to the work W _a is to be able to grip the substantially workpiece W _a generated It is defined as the time required.

The back electromotive force detection circuit 48 is connected to the first finger member 36.
It is provided to set the pressing forces of a, 36b, and 36c to be within a predetermined allowable value. That is, the first
The fingers members 36a, 36b, 36c is by being pressed further inward in contact with the outer peripheral surface of the workpiece W _A, the servo motors 20a, 20b, the counter electromotive force to 20c each motor coil of generator This voltage value is a value corresponding to the pressing force (pressing force) by the first finger members 36a, 36b, 36c. In this way, by detecting the back electromotive force generated in each of the motor coils and controlling the voltage value of the back electromotive force so as not to exceed a predetermined value, the first finger members 36a, 36b, 36c Is regulated so as to be within a predetermined allowable value.

In the hand device 10 configured as described above, works of various shapes will be described below by using three first finger members 36.
The gripping operation of gripping by a, 36b, and 36c will be described.

First, in the case of holding a work of any shape, three first finger members 36 are attached to the outer periphery of the work to be gripped based on a robot control procedure (not shown).
The hand main body 18 is moved so that a, 36b, and 36c are located. In each of the drive cylinder mechanisms 32a, 32b, and 32c, compressed air is set to be introduced into one of the input ports. As a result, the movable second finger member 34a,
34b, 34c are in a state of being taken into the corresponding first finger members 36a, 36b, 36c.

When gripping the cylindrical workpiece W _A shown in FIG. 4A, the control Yunitsuto 42 based on the setting information from Teichingu Units - 44, the motor drivers 38a, 38b, 38
A control signal is output to c so that the first arms L ₁ , L ₂ , L ₃ rotate along the same direction. Upon receiving this control signal, each of the motor drivers 38a, 38b, 38c sends the corresponding first arm L
_A drive signal is output so that ₁ , L ₂ and L ₃ are rotationally driven, for example, clockwise. Thus, the cylindrical work W _A
It is reliably gripped in the state of being distributed to the outer periphery equally by a first arm L _1, L _2, L ₃ first rotation of the three pivoting In conjunction to the of finger members 36a, 36b, 36c Will be.

Here, FIG. 5 shows a cylindrical work W _A shown in FIG. 4A.
2 is a flow chart showing a specific control procedure in the control unit 42 for gripping by the hand device 10 shown in FIG. 1 and FIG. Hereinafter, based on the flow Chiya over chestnut yer preparative, illustrating a control procedure in the case of gripping a cylindrical workpiece W _A.

First, as shown in step S10, the first arm L ₁ ,
It is determined whether or not L ₂ and L ₃ are each at the origin position. If NO is determined in step S10, that is, if it is not confirmed that the first arms L ₁ , L ₂ , L ₃ are at the origin positions, a control unit of a robot (not shown) is determined in step S12. Wait for an article gripping command signal from the controller to be output, and when the article gripping command signal is output, step S14
In the servo motor 20a, 20b, to drive 20c in respectively clockwise, the first arm L _1, L _2, L ₃ corresponding to a clockwise direction moving along connexion times. And the servo motor 20a,
While each of 20b and 20c is being driven, in step S16, it waits for the output of the origin signal from the corresponding encoder 26a, 26b, 26c via each position detection circuit 40a, 40b, 40c.

When the origin signal in step S16 is the encoders 26a, 26b, that is output from 26c is detected, in step S18, the arm L ₁ each first at this detection time point, L _2, L ₃ of rotation The position is set as an initial position, and the amount of each rotational drive is reset. Thus, each first
The initial positions of the arms L ₁ , L ₂ , and L ₃ are accurately set.

Incidentally, when it is judged as YES in step S10, i.e., in advance when the first arm L _1, L _2, L ₃ confirms that the origin position, going through the step S12, S14, S16 without directly jumps to step S18, the arms L ₁ of each of the 1, L _2, L
Set the stop position of ₃ as the initial position.

Then, after the thus was the initial position of the first arm L _1, L _2, L ₃ and each set, so that the concrete grasping operation of the workpiece W _A in the hand device 10 is started. Here, when gripping the workpiece W _A cylindrical as shown in FIG. 4A is the same rotate in the same direction with respect to the axial center line of each first arm L _1, L _2, L ₃ and connecting rod 16 What is necessary is just to control the servo motors 20a, 20b, 20c so as to rotate by an amount.

That is, the initial position of the first arm L _1, L _2, L ₃ are respectively set at step S18, in step S20,
Servo motors 20a, 20b, 20c are each driven clockwise,
The corresponding first arms L ₁ , L ₂ , L ₃ are each driven to rotate clockwise. Simultaneously with the start of this step S20, in step S22, a timer (not shown) in the energization time setting circuit 46 is started, and a timer operation of a preset energization time is started.

Thereafter, in step S24, the timer started in step S22 is monitored to determine whether or not the predetermined energization time has timed out. Then, when it is detected in step S24 that the predetermined energization time has timed out, as described above, the first finger members 36a, 36b, 36
it means that means that the state in which the workpiece W _A is gripped with sufficient pressing force is achieved by c, step S26
In, the operation of energizing the respective motor coils of the servo motors 20a, 20b, and 20c is stopped.

In this way, the gripping operation of the cylindrical workpiece W _A in the hand device 10 is completed, in step S28,
Based on a control signal from a robot controller (not shown),
Robotsutoamu 12 is moved, not accompanied with the movement of the Robotsutoamu 12, the hand device 10 is moved, also it will be moved workpiece W _A which is gripped thereto. Then, in step S30, when it is detected that the hand device 10 has been transported to a predetermined position, in step S32,
The movement operation of the robot arm 12 is stopped.

Then, in step S34, the servo motors 20a, 20a
b, 20c and by driving the respective counter-clockwise, the first arm L _1, L _2, L ₃ corresponding to the counterclockwise direction moving along connexion times. In this way, the work W _A by the first finger members 36a, 3b, 36c
Backed by a gripping state release, the workpiece W _A it will be left to the mobile position. Thereafter, the driving of each servomotor 20a, 20b, 20c in the counterclockwise direction is continued until the origin signal is output from the corresponding encoder 26a, 26b, 26c in step S36. Then, in step S36, each encoder 26a, 2
When it is detected that the origin signals are output from 6b and 26c, the power supply to each of the servomotors 20a, 20b and 20c is stopped in step S38. Thus, each first arm
L ₁ , L ₂ , and L ₃ are kept stopped at the respective origin positions.

In this way, a series of workpieces in the hand device 10
Gripping operation of the W _A is finished, the control procedure in the control Yunitsuto 42 ends.

Note that, as described above, the hand device 10 of this embodiment is
Is provided with a back electromotive force detection circuit 48, so that step S2
In 4, when the back electromotive force detection circuit 48 detects the back electromotive force generated in each motor coil until the set time expires, the control unit 42 does not wait for the set time to elapse. Servo motor 20a, so that the voltage value of this back electromotive force does not exceed a predetermined value
Control is performed to cut off the current supply to 20b and 20c. In this way, the pressing force by the first finger members 36a, 36b, 36c is regulated to be within a predetermined allowable value.

Here, in one embodiment described above, the workpiece W _A is 3
In a state where the first finger members 36a, 36b, and 36c are gripped with a predetermined pressing force, each servomotor 20a, 20b,
Although it has been described that the power supply to the motor coil of 20c is cut off, the present invention is not limited to such a configuration, for example, as another embodiment with reference to FIGS. 6A and 6B. As shown in the figure, the state of energizing the motor coil may be continued to electrically secure the gripping state.

In the following, the work W _A has three first finger members 36a, 36
A description will be given of a configuration of another embodiment in which the amount of current supplied to the motor coil is maintained substantially constant after being gripped by b and 36c. That is, in another embodiment described below, unlike the above-described embodiment, the energization time setting circuit 46 and the back electromotive force detection circuit 48 are not provided, and instead, the torque holding circuit 50 and the constant torque The detection circuit 52 is connected.

In the following description, each servo motor 20a, 20b,
Since the control system in 20c is the same, the servo motor 20a
Only the control system of the servomotors 20b and 20c will be described, and description of the control system of the servomotors 20b and 20c will be omitted.

That is, as shown in Figure 6A, the motor driver 38a which is connected to the servo motor 20a is, NPN type first transistor TR ₁ and the first resistor as a current supply to the motor coil R ₁
Are composed of a, to the first emitter of the transistor TR ₁ is input, The collector includes a first resistor R ₁
Are respectively connected to the motor coils of the servo motor 20a.

Here, the motor driver 38a, the pressing force for gripping the workpiece W _A, i.e., the torque holding circuit 50 for holding the rotational torque of the first finger member 36a constant is connected. As shown in FIG.
Second transistors TR ₂ of the connected PNP type in parallel to the first ends of the resistor R _1, the third of the connected NPN type in parallel between the first transistor TR ₁ base and emitter the transistor TR _3, and a second and third resistor R _1, R ₂ Prefecture.

In particular, the second of the base of the transistor TR _2, the first
The collector of the transistor TR ₁ and connected to the connecting point between the first resistor R _1, the emitter is connected to the connecting point between the first resistor R ₁ and the motor coil. Further, a second transistor TR ₂ collectors and the third transistor TR ₃ of the base, are connected to each other via a third resistor R _3, the collector of the third transistor TR ₃ includes a first transistor TR ₁ and grounded via a _second resistor R2.

Further, the constant torque detection circuit 52 for detecting the value of the torque held constant in the torque holding circuit 50 includes:
NPN-type fourth transistor TR ₄ and fourth and fifth resistors
It is configured with R ₄ and R ₅ . That is, the fourth of the emitter of the transistor ₄ inputs described above, based on the fourth collector resistor R ₄ via the second transistor TR _2, are respectively connected, also, collector fifth resistor R Grounded through _five . The detection end for detecting a predetermined torque is connected to the collector of the fourth transistor TR _4.

In the control system configured as described above, when an article gripping command signal is output from a control unit of a robot (not shown), a predetermined voltage is supplied from the input terminal in accordance with the signal. That is, the current supplied from the input terminal, the first transistor TR ₁ is turned on in the motor driver 38a, as a result, current through connexion transistor TR ₁ of the first, the corresponding servo motor 20a motor coil Will be energized. In this way, so that the servo motor 20a is activated, the first arm L ₁ begins to rotate.

Here, as shown in Figure 6B, a first in which the first rotation start time t ₀ of the arm L _1, attached to the first arm L ₁
During the up time t ₁ finger member 36a comes into contact with the workpiece W _A, the servo motor 20 _1, since whatever load is not applied, the current flowing through the motor coil, i.e., the servo motor 20
The torque exerted at a is small. As a result, the current value appearing at the detection end also becomes a small value as shown in FIG. 6B.

Thereafter, when the first finger member 36a abuts against the workpiece W _A, the first rotation of the arm L ₁ becomes to be blocked,
For this reason, the load on the servomotor 20a increases, and the value of the current flowing through the motor coil gradually increases. As a result, the potential difference induced in the first ends of the resistor R ₁ will be increased not accompanied the increase in the current. As shown in Figure 6B, reaches the time t _2, the potential difference becomes higher than the second inversion voltage of the transistor TR ₂ of the torque holding circuit 50, at this point, the second transistor TR ₂ is turned, slave connexion, the third transistor TR ₃ is also turned on, as a result, the first transistor TR ₁ which constitutes the motor driver 38a is decided to oFF. Thus, the motor driver 38a stops energizing the motor coil, and the amount of current flowing through the motor coil decreases.

Thereafter, when reaching the time point t _3, the potential difference generated in the first ends of the resistor R ₁ is lower than the second inversion voltage of the transistor TR _2, as a result, the second transistor TR ₂ is turned off , slave shall be applied to any off the third transistor TR _3, as a result, the first transistor TR ₁ will be turned on again, resuming the power supply to the motor coil.

In this way, the first transistor TR ₁ is turned on and
By repeating the OFF operation, the amount of current supplied to the motor coil is maintained at a substantially constant value, that is, the torque exerted by the servomotor 20a is maintained at a substantially constant value.

On the other hand, the fact that the torque of the servo motor 20a is held constant by the torque holding circuit 50 in this way is configured to be detected by a detection signal output from the detection end of the constant torque detection circuit 52. As a result, based on the detection signal from the constant torque detection circuit 52, the robot control unit detects that the servo motor 20a is exerting a constant torque based on the detection signal from the constant torque detection circuit 52. _Since it means that the gripping of _A is achieved with a predetermined pressing force, the robot arm
12 by moving the will control to start the operation of moving the workpiece W _A.

Thus, in other embodiments, without interrupting the current to the servo motor 20a, while continuing the current supply, it can be maintained in a state holding the workpiece W _A with a predetermined pressing force Becomes

Further, plate-shaped work W _B standing upright as shown in Figure 4B
When the control unit 42 grasps, the control unit 42 outputs a control signal as described below to each of the motor drivers 38a, 38b, 38c based on the setting information from the teaching unit 44. That is, in this case, by the work W _B ,
The three first finger members 36a, 36b, 36c are divided into two groups, one and two.

Here, the motor driver 38a for rotationally driving the first finger member 36a that is isolated in one, so that the first finger member 36a to pivot in the direction in which it can abut sooner workpiece W _B , And a control signal is output. On the other hand, the motor drivers 38b and 38c for turning and driving the first finger members 36b and 36c combined into two pieces are provided in a state where they are opened (that is, a state where they are rotated in a direction away from each other). in to abut the workpiece W _B, the control signal is output. In response to this control signal, each motor driver 38
a, 38b, 38c are corresponding arm L _1, L _2, L _3, for example, clockwise, counterclockwise, and outputs a drive signal to drive along connexion respectively rotated in the clockwise direction.

In this way, upstanding plate-shaped workpiece W _B are three first fingers member 36a, 36b, will be reliably gripped by 36c.

The Figure 7A, each of the first finger 36a when grasping the plate-shaped workpiece W _B shown in Figure 4B, 36b, 36c with the rotation condition is indicated in such a plate-shaped workpiece W _B The control procedure for gripping is shown as a flowchart in FIG. 7B. In this control procedure, the servomotors 20a, 20a
b, as 20c of the control system, the place described as another example in the work W _A described above, even after the grasping operation of the workpiece W is completed, in order to hold the pressing force, the power supply to the motor coil It is assumed that a continuous configuration is adopted.

First, as shown in step S40, the first arm L ₁ ,
It is determined whether or not L ₂ and L ₃ are each at the origin position. Then, this step when it is determined as NO in S40, i.e., if the first arm L _1, L _2, L ₃ are in each origin position is not confirmed, the control unit of the robot (not shown) at step S42 Waiting for an article gripping command signal from the controller, and when this article gripping command signal is output, step S44 is performed.
In the servo motor 20a, 20b, to drive 20c in respectively clockwise, the first arm L _1, L _2, L ₃ corresponding to a clockwise direction moving along connexion times. And the servo motor 20a,
While each of 20b and 20c is being driven, in step S46, it waits for the output of the origin signal from the corresponding encoders 26a, 26b and 26c via the position detection circuits 40a, 40b and 40c.

When the origin signal at step S46 is the encoders 26a, 26b, that is output from 26c is detected, in step S48, the arm L ₁ each first at this detection time point, L _2, L ₃ of rotation The position is set as an initial position, and the amount of each rotational drive is reset. Thus, each first
The initial positions of the arms L ₁ , L ₂ , and L ₃ are accurately set. Here, the origin position of the first arm L _1, L _2, L ₃ when gripping the plate-shaped workpiece W _B, each first arm
L ₁ , L ₂ , and L ₃ are respectively defined by positions extending outward along a bisector that bisects the corresponding apex angle of the hand body 18 forming the triangle.

Incidentally, when it is judged as YES in step S40, i.e., in advance when the first arm L _1, L _2, L ₃ confirms that the origin position, going through the step S42, S44, S46 without directly jumps to step S48, the arms L ₁ of each of the 1, L _2, L
Set the stop position of ₃ as the initial position.

After setting the initial positions of the first arms L ₁ , L ₂ , and L ₃ in this way, in step S50, the robot arm 12 is moved to move the hand device 10 to the work W _B.
Is moved to a position where a predetermined posture is taken. And the predetermined position, as shown in Figure 7A, the first finger member 36a separated into one, the distance to the workpiece W _B,
Just it is set so as to match the operation radius r ₁ of the first arm L _1.

Next, in step S52, the first separated
The arm L ₁ of, by driving the corresponding servo motor 20a,
As shown in FIG. 7A, the first finger member 36a is
To along connexion rotation angle theta ₁ a counterclockwise direction to a position in contact with the surface of the _B.

On the other hand, in step S54, the two first arms L ₂ and L ₃ are driven by the corresponding servo motors 20b and 20c, respectively, so that the first arms L ₂ and L ₃ are rotated counterclockwise and clockwise as shown in FIG. 7A. Rotate in a state along each. The rotation direction of the first arm L _2, L ₃ is to be defined appropriately by the thickness and the like of these operating radius r _2, r ₃ of the length and the workpiece W _B.
Incidentally, the timing at which the first finger member 36a contacts the surface of the workpiece W _B at step S52, the timing at which the first finger members 36b, 36c are in contact with the back surface of the workpiece W _B at step S54, the same Thus, the respective start timings are defined.

Thereafter, three first fingers member 36a, 36b, after the 36c comes into contact with the front and back surfaces of the workpiece W _B, step
In S56, it is determined that a detection signal is output from constant torque detection circuit 52. And this step S56
When the output of the detection signal from the constant torque detecting circuit 52 is detected in a first finger member 36 work W _B is the three
It is determined that the gripped state has been achieved by a, 36b, and 36c, and in step S58, the robot arm 12 is controlled based on a control signal from a robot controller (not shown).
Is moved. The hand device 10 is moved along with the movement of the robot arm 12, and the work held by the hand device 10 is moved.
W _{B will} also be moved.

Then, when it is detected in step S60 that the hand device 10 has been transported to a predetermined position, the moving operation of the robot arm 12 is stopped in step S62. Then, in step S64, the servo motor 20a, 20b, a 20c, respectively, to the rotational direction during the gripping operation by along connexion driven in a rotational direction opposite the first arm L _1, L _2, L ₃
Are rotated respectively. Thus, the first finger member
36a, 36b, 36c are gripped state of the workpiece W _B is released by the workpiece W _B it will be left to the mobile position.

Thereafter, the driving of each of the servomotors 20a, 20b, 20c in the direction opposite to the direction of the gripping operation is continued until the origin signal is output from the corresponding encoder 26a, 26b, 26c in step S66. Then, in step S66, the detection of the origin signal from each of the encoders 26a, 26b, 26c is detected, and in step S68, the power supply to each of the servomotors 20a, 20b, 20c is stopped. In this way, the first arms L ₁ , L ₂ , and L ₃ are kept stopped at the origin positions. In this way, the grasping operation of the workpiece W _B is completed in the sequence of the hand device 10, the control procedure in the control Yunitsuto 42 ends.

Further, in the case of gripping a workpiece W _C of arbitrary shape as shown in 4C diagrams, control Yunitsuto 42 based on the setting information from Teichingu Units - 44, the motor drivers 38a,
38b, in 38c, and it outputs a control signal which is set to be optimal for grasping the workpiece W _C of arbitrary shape in three points.

In this way, the work W _C of an arbitrary shape is
The finger members 36a, 36b, 36c surely hold the finger members.

On the other hand, as shown in FIG.
In the case of gripping a workpiece W _D to D _1, D _2, D ₃ is formed, the control Yunitsuto 42 based on the setting information from Teichingu Units - 44, first, the drive cylinder mechanism 32
The movable second finger members (third arms) 34a, 34b, 34c are switched to corresponding fixed first finger members (third arms) by switching to introduce compressed air to the other input ports of the a, 32b, 32c. The second arm 36a, 36b, 36c is taken out further from the lower end. After this, the control unit 42
The entire hand device 10 is lifted at once, and a control signal is output to each motor driver 38a, 38b, 38c so that the three movable finger members 34a, 34b, 34c are located immediately above the corresponding holes.

Then, the control unit 42 lowers the entire hand device 10 to insert the movable second finger members 34a, 34b, 34c into the corresponding holes, and thereafter, the motor drivers 38a, 38
b, with respect to 38c, and the first arm L _1, L _2, L ₃ corresponding rotated, the second finger members 34a of the movable, 34b, 34c outputs a control signal to pivot in the hole . As a result, the second finger members 34a of the movable, 34b, 34c is brought into contact with the peripheral surface of the corresponding hole, the second finger members 34a of the workpiece W _D These three movable, 34b, ensured by 34c Will be grasped.

The FIG. 8A, each of the first finger 36a when grasping the apertured workpiece W _D shown in FIG. 4D, 36b, with 36c rotation state of is shown, gripping such apertured workpiece W _D The control procedure for performing this is shown as a flowchart in FIG. 8B. In this control procedure, the servomotors 20a, 20a
b, as 20c of the control system, as in the work W _B described above, even after the grasping operation of the workpiece W is completed, in order to hold the pressing force, the structure being continued energization of the motor coil It is assumed that they are employed.

First, as shown in step S70, the first arm L ₁ ,
It is determined whether or not L ₂ and L ₃ are each at the origin position. Then, this step when it is determined as NO in S70, i.e., if the first arm L _1, L _2, L ₃ are in each origin position is not confirmed, the control unit of the robot (not shown) at step S72 Waiting for an article gripping command signal from the controller, and when this article gripping command signal is output, step S74 is performed.
In the servo motor 20a, 20b, to drive 20c in respectively clockwise, the first arm L _1, L _2, L ₃ corresponding to a clockwise direction moving along connexion times. And the servo motor 20a,
While each of 20b and 20c is being driven, in step S76, it waits for the output of the origin signal from the corresponding encoders 26a, 26b and 26c via the position detection circuits 40a, 40b and 40c.

When the origin signal at step S76 is the encoders 26a, 26b, that is output from 26c is detected, in step S78, the arm L ₁ each first at this detection time point, L _2, L ₃ of rotation The position is set as an initial position, and the amount of each rotational drive is reset. Thus, each first
The initial positions of the arms L ₁ , L ₂ , and L ₃ are accurately set.

Here, the origin position of the first arm L _1, L _2, L ₃ when gripping the apertured workpiece W _D, as in the case of plate-shaped work W _B, arm L ₁ of each of the first , L ₂ , and L ₃ are respectively defined by positions extending outward along a bisector that bisects the corresponding apex angle of the hand body 18 forming the triangle.

Incidentally, when it is judged as YES in step S70, i.e., in advance when the first arm L _1, L _2, L ₃ confirms that the origin position, going through the step S72, S74, S76 without directly jumps to step S78, the arms L ₁ of each of the 1, L _2, L
Set the stop position of ₃ as the initial position.

After setting the initial positions of the first arms L ₁ , L ₂ , L ₃ in this way, in step S80, the servo motors 20a, 20b, 20c are driven to drive the second finger members 34a, 34a, As shown in FIG. 8A, the center positions of 34b and 34c are set so that the center positions of the corresponding holes D ₁ , D ₂ and D _{3 respectively} match. These servo motors 20a, 20b, 20c
The rotation amount and the rotation direction are determined in the control unit 42 such that the operation time is the shortest.

Next, in step S82, the hand device 10 is moved to a predetermined position by moving the robot arm 12. Incidentally, the provisions the predetermined position, as shown in Figure 7A, the second finger members 34a, 34b, 34c is the position that has been brought to just above the position of the hole D _1, D _2, D ₃ respectively corresponding to Have been.

Then, in step S84, the drive cylinder mechanism 32
a, 32b, and 32c, respectively, to activate the second finger members 34a, 34a.
b, 34c are moved so as to protrude downward from the corresponding first finger members 36a, 36b, 36c. As a result, the second finger members 34a, 34b, 34c will each be inserted. It in a corresponding hole _{D 1, D 2, D 3} . In addition, these second finger members
The amount of downward projection of 34a, 34b, 34c is determined to a predetermined value by a drive signal from control unit 42.

Thereafter, in step S86, the servo motors 20a, 20
By driving b and 20c, respectively, they rotate in the clockwise, counterclockwise, and clockwise directions, respectively. The rotation directions of the first arms L ₂ and L ₃ are only required to be defined so that the rotation direction of one of the servomotors is different from the rotation direction of the other two servomotors. is there.

In this manner, the three second finger members 34a, 34b,
34c is brought into contact with the inner peripheral surface of the hole D _1, D _2, D ₃ corresponding the workpiece W _D, the workpiece W _D, these second finger members 34a, 34b, 34
It will be grasped by c. After the gripping operation is performed as described above, it is determined in step S88 that the detection signal is output from the constant torque detection circuit 52.

When the output of the detection signal from the constant torque detection circuit 52 in this step S88 is detected, the first finger member 36a workpiece W _B is the three, 36b, is a state of being securely gripped by 36c is achieved Determined that the
In, the robot arm 12 is moved based on a control signal from a robot controller (not shown). Incidentally, In conjunction with the movement of the Robotsutoamu 12, the hand device 10 is moved, also it will be moved workpiece W _D which is gripped thereto.

Then, in step S92, when it is detected that the hand device 10 has been transported to a predetermined position, the moving operation of the robot arm 12 is stopped in step S94. Then, in step S96, the servo motors 20a, 20b, 20c are driven to drive the second finger members 34a, 34a.
b, or 34c center position of each of the center positions of the corresponding holes D _1, D _2, D ₃ is rotated to match. By this rotation, the work
The holding state of W _D is released.

Thereafter, in step S98, the drive cylinder mechanism 32
a, 32 b, 32c to return the up to respective initial position, as a result, the second finger members 34a, 34b, 34c are corresponding holes D _1, D _2, D ₃
Will be withdrawn upwardly from the workpiece W _D will be left to the mobile position. Then, in step S100, the servo motor 20a, 20b, a 20c, respectively, to the direction of rotation determined in step S80 and along connexion driven in a rotational direction opposite the first arm L _1, L _2, L ₃ Each turns.

Thereafter, the driving of each servomotor 20a, 20b, 20c is continued until the origin signal is output from the corresponding encoder 26a, 26b, 26c in step S102. And step S1
In 02, the detection of the origin signals from the encoders 26a, 26b, 26c is detected, and the energization of the servomotors 20a, 20b, 20c is stopped in step S104. In this way, the first arms L ₁ , L ₂ , and L ₃ are kept stopped at the origin positions. In this way, the grasping operation of the workpiece W _B is completed in the sequence of the hand device 10, the control procedure in the control Yunitsuto 42 ends.

As described in detail above, according to this embodiment, the hand device 10 is configured such that the work as a part is divided into three finger members (fixed first finger members 36a, 36b, 36c or movable second finger members). Irrespective of the members 34a, 34b, and 34c), it is possible to hold it, so that it can function as a so-called general-purpose hand device. , It is not necessary to prepare various hand devices in advance, so that the cost can be reduced and the space can be effectively used.

It is needless to say that the present invention is not limited to the configuration of the above-described embodiment, but can be variously modified without departing from the gist of the present invention.

For example, in one embodiment described above, the first finger members 36a, 36b, 36c are movable second finger members 34a, 34a.
Incorporating b, 34c, it has been described that no matter which finger member is used, it is grasped using frictional engagement force,
Without being limited to this, the movable second finger member
Instead of 34a, 34b, and 34c, a bakyum tube or bakyum pad may be adopted, and the bakyum tube or bakyum pad may be configured to grip a part by using a suction force. With such a configuration, the most appropriate one is selectively used in comparison with using the frictional engagement force and using the suction force, depending on the shape of the component, It is possible to more reliably and efficiently grip the component.

Further, in the above-described embodiment, the description has been made such that the finger members include the fixed and movable finger members for utilizing the frictional engagement force, but the present invention is not limited to this. For example, a bakyum tube or a bakyum pad may be used. Needless to say, it may be configured as a finger member and configured to hold the component by a suction force.

Furthermore, in the above-described embodiment, the lower end of the connection rod 16 has been described as being connected at the center of gravity of the hand main body 18. However, the present invention is not limited to this.
The connection can be made at any of the eighteen positions.

[Effects of the Invention] As described above in detail, the component gripping hand device according to the present invention includes a hand main body, at least three shafts attached to the hand main body, and a rotating unit that rotates each of the shafts. And a first arm attached to each of the shafts;
Fingers provided on each of the first arms for gripping articles; and control means for controlling the rotation of the first arm for gripping the articles with the fingers. It is characterized in that it comprises a control means for defining a rotation direction and a rotation angle, and a teaching means for teaching the rotation direction and the rotation angle of the rotation means.

Therefore, according to the present invention, there is provided a general-purpose component gripping hand device capable of reliably gripping components of various shapes only by providing one hand device.

Further, according to the present invention, at least three fingers for gripping the article are provided, and each finger is provided with an independent driving means so that the moving amount and the moving direction of each finger can be different, respectively. Thus, there is provided an article gripping hand device capable of causing each drive means to perform an operation corresponding to the article.

Further, according to the present invention, the first arms are respectively fixed to the three independently rotating shafts, the fingers for holding the articles are attached to the respective first arms, and each of the fingers is attached to each of the fingers. An article gripping hand device capable of providing a second finger that expands and contracts is provided.

Further, according to the present invention, in a hand device in which at least three fingers to which driving force is applied by a driving means, for example, a motor, have a member, an article gripping hand capable of improving the reliability of article gripping. A device will be provided.

Further, according to the present invention, there is provided an article gripping hand device capable of outputting a signal of gripping an article by a finger member and moving to the next step by this gripping signal. Will be done.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the configuration of an embodiment of an article gripping hand device according to the present invention; FIG. 2 is a top view showing the turning state of three first arms; FIG. FIG. 4A to FIG. 4D are top views showing various shapes of workpieces to be gripped by the hand device of this embodiment; FIG. 5 is FIG. FIG. 6A is a flow chart showing a control procedure for gripping the work shown in FIG. 6; FIG. 6A is a circuit diagram showing a configuration of a control system according to another embodiment for gripping the work W shown in FIG. 4; 6A is a diagram showing the state of a detection signal output from the detection end based on the control system shown in FIG. 6A; FIG. 7A shows the rotation state of the first finger when gripping the work shown in FIG. 4B; FIG. 7B is a flowchart showing a control procedure for gripping the work shown in FIG. 4B. FIG. 8A is a view showing a rotating state of a second finger member when gripping the work W shown in FIG. 4D; and FIG. 8B is a control procedure for gripping the work shown in FIG. 4D. It is a flowchart shown. In the figure, 10 ... hand device, 12 ... robot arm, 14 ...
... Mounting member, 16 Connection rod, 18 Hand body, 20
a; 20b; 20c ... servo motor, 22a; 22b; 22c ... reduction mechanism, 24a; 24b; 24c ... output shaft, 26a; 26b; 26c ... encoder, 28a; 28b; 28c ... mounting plate, 30a ; 30b; 30c ... Finger mounting plate, 32a; 32b; 32c ... Drive cylinder mechanism, 34a; 34b; 3
4c... Piston (movable second finger member), 36a; 36
b; 36c... fixed first finger members, 38a; 38b; 38c.
Motor driver, 40a; 40b; 40c ... Position detection circuit, 42 ...
… Control unit, 44 …… Teaching unit, 46 ……
Energizing time setting circuit, 48 ... Back electromotive force detection circuit, 50 ... Torque holding circuit, 52 ... Constant torque detection circuit, D ₁ ; D ₂ ; D ₃ ...
... holes, L ₁ ; L ₂ ; L ₃ ... are the first arms.

Claims (1)

(57) [Claims] 1. A hand body, at least three shafts attached to the hand body, rotation means for rotating each of the shafts, a first arm attached to each of the shafts, A finger provided on one arm for gripping an article; and the first finger for gripping the article with these fingers.
Control means for controlling the rotation of the arm, the control means for defining a rotation direction and a rotation angle of the rotation means, and a teaching means for teaching the control means the rotation direction and the rotation angle of the rotation means. And a hand device for gripping parts.