JP2975822B2 - Robot hand - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot hand used for a store robot or the like.

[0002]

2. Description of the Related Art As an example of a hand for a food transport robot intended for use in a store or the like, Japanese Patent Application Laid-Open No. 3-197 is disclosed.
No. 83 and Japanese Unexamined Utility Model Publication No. 4-29387 can be cited. In the former “work holding mechanism”, a weight sensor is mounted on the finger of the hand unit, the weight of the work having the flange is supported by the upper surface of the finger, and the detection result of this weight sensor is placed on the table. It is used for placing operation. In the latter "robot hand," a plate that moves freely up and down on the finger of the hand part and an elastic body that urges the plate upward are provided, and a work for handling is placed on this plate to detect sinking of the plate. And confirms whether or not the workpiece is loaded.

[0003]

The latter "robot hand" can detect the presence or absence of a workpiece for handling or the presence or absence of a workpiece loaded on the workpiece for handling, but when a plurality of workpieces are loaded on the workpiece for handling. It cannot be distinguished which work is loaded and which is not. From the former configuration of the “work holding mechanism”, it is possible to easily estimate the action of specifying the type or quantity of the work loaded on the handling work by the output value of the weight sensor. However, in this configuration, since the handling work directly contacts the weight sensor, an impact force is repeatedly applied thereto, which may shorten the life of the expensive weight sensor. Accordingly, the present invention provides a robot hand that detects the loaded state of a plurality of workpieces on a workpiece for handling (hereinafter, referred to as transporting assistance) simply and inexpensively without using an expensive weight sensor. Aim.

[0004]

In the robot hand according to the present invention, the gripping fingers grip the lower part of the transport auxiliary work having the flange at the upper part from the flange, and the transport auxiliary work is moved up and down. A pair of left and right fingers that are held to the extent that they can be moved, and a pair of left and right plates that are vertically movably fitted to the upper surface of each finger and that support the lower surface of the flange of the auxiliary work for transportation are provided. Then, an elastic body for urging the plate up and down is inserted between the plate and the finger, and each finger is provided with a position detecting means for detecting a state of the plate moving up and down with respect to the upper surface of the finger, and height information of the plate detected by the position detecting means is provided. Is compared with height data set in advance according to the weight of each type of work, and it is determined whether a predetermined work is placed on the auxiliary work for transportation.

Further, in the robot hand of the present invention, a pair of left and right fingers for holding the lower portion from the flange portion of the auxiliary work for transportation so that the auxiliary work for transportation can be moved up and down; A pair of left and right plates are provided to be fitted to the upper surface so as to be vertically movable and to support the lower surface of the flange of the auxiliary work for transportation. Then, an elastic body that urges the plate upward is inserted between the plate and the finger, and a position detector for detecting the lifting state of the plate with respect to the upper surface of the finger is provided for each finger, and height information of the plate detected by the position detector is provided. Is compared with height data set in advance according to the weight of each type of work, and it is determined whether a predetermined work is placed on the auxiliary work for transportation.

[0006]

According to a change in the relative position of each plate in the up-down direction with respect to the finger, the work placement state on the auxiliary work for transport is detected.

[0007]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of the robot hand according to the present invention. The robot hand 1 comprises a main body 11, fingers 2, a plate 3, an elastic body 4, and position detecting means 5, and the main body 11 is shown. The position detection means 5 is connected to a discriminating device 6 provided in a control unit of the robot. In the present invention, the auxiliary work 10 for transport (FIG. 2 or FIG. 3) in which the large-diameter disk 102 is fixed on the small-diameter cylindrical portion 101 is transported in a horizontal state, so that the auxiliary work 10 for transport is mounted on the auxiliary work 10 for transport. It is assumed that a robot transports various works (A and B in FIGS. 4 to 6) to a predetermined position.

The main body 11 has a driving source such as a motor inside, and causes the pair of right and left fingers 2 to linearly move in a direction approaching or moving away from each other to perform an opening / closing operation. (The horizontal direction in FIG. 1 is the left-right direction, the depth direction is the front-rear direction, and the vertical direction is the up-down direction.) This opening / closing stroke is determined by the cylindrical portion 101 of the carrying auxiliary work 10 shown in the plan view of the robot hand 1 in FIG. Is a distance that can be pinched and released. The force holding the cylindrical portion 101 is such that the cylindrical portion 101 slides in the vertical direction but does not deviate in the front-rear direction.

Each of the fingers 2 is cut off from the end to the vicinity of the main body 11 at the top side when the finger 2 is in a horizontal sideways posture.
Up and down movement space. Reference numeral 21 denotes a through hole extending from the upper surface of the cutout portion 20 to the lower surface of the finger 2, and as shown in FIG. The four through holes 21 are located below a disk portion (hereinafter, referred to as a flange portion) protruding from the cylindrical portion when the finger 2 sandwiches a predetermined position of the cylindrical portion 101 of the auxiliary work 10 for transportation. They are all placed at the same distance from the center. Each through hole 21
The upper side is smaller and the lower side is larger in diameter, and the linear guide bearings 22 are fitted into and fixed to the small diameter portions.

A pair of front and rear guides 31 are fixed to the lower surfaces of the plates 3, respectively, and the respective guides 31 are inserted into the through holes 21 via the linear guide bearings 22.
The lower end of the guide 31 has a large diameter, and the guide 3
1 does not come out upward. The elastic body 4
In the present embodiment, a compression coil spring is used. The compression coil spring is mounted on each of the guides 31 and mounted between the upper surface of the linear guide bearing fixed to the through hole and the lower surface of the plate 3, respectively.
It is urged upward from the finger 2. When only the transport auxiliary work 10 is placed on the plate 3, the plate 3
The length of the guide 31 and the spring pressure of the compression coil spring 4 are set so that the upper surface of the compression coil spring 4 is flush with the upper surface of the finger 2.

Reference numeral 32 denotes a contact sensor made of a conductive rubber or the like attached to the upper surfaces of both plates 3 and detects when the flange of the disk 102 of the auxiliary work 10 for transport is placed on the plate. Things. Also, both plates 3 have a symmetrical shape as shown in FIG. 1, and three types of protrusions 33, 34, 35 are provided at symmetrical positions. The pair of left and right position detecting means 5 arranged on the outer surface of the pair 2 are operated.
Since the pair of fingers 2, the plate 3, and the position detecting means 5 have symmetrical shapes or arrangements, respectively, only the right-hand side in FIG. 1 will be described for convenience of explanation. The protruding piece 33 once extends horizontally to the right and protrudes from the outer edge of the finger 2, and then extends vertically downward to form the cut portion 20.
To the right side of the finger below. An actuator 511 of the switch 51, which will be described later, corresponding to the projecting piece 33 exists in a space in which the projecting piece 33 moves up and down due to the vertical movement of the plate 3. The projecting piece 34 is located behind the projecting piece 33,
Similarly to the above, the finger reaches the right side surface of the finger below the cutout portion 20, but the length extending downward is slightly shorter than the protruding piece 33. Protruding piece 3
The switch 5 corresponding to the protruding piece 34 is provided in the vertical movement space 4.
There are two actuators 521. The projecting piece 35 is located behind the projecting piece 34, extends horizontally rightward, and protrudes from the outer shape of the finger 2. An actuator 531 of the switch 53 corresponding to the projecting piece 35 exists in the vertical movement space. I do.

The position detecting means 5 comprises three switches 51, 52, 53 corresponding to the protruding pieces 33, 34, 35 of the plate 3, respectively, and is attached to the right side of the finger below the cutout 20. The switch 51 is configured such that a hinge lever-shaped actuator 511 is rotatably mounted on the switch body and performs on / off operation by the rotation of the actuator. The switch 51 is mounted on the right side of the finger 2 such that the actuator 511 is on the front side. Can be Then, when the rotation range of the actuator 511 overlaps the vertical movement space of the protruding piece 33 and the protruding piece 33 comes down to a predetermined position, the actuator 511 is turned backward and the switch 51 is turned on. Become. The switch 52 has the same shape as the switch 51, and is mounted behind the switch 51 so that the actuator 521 is on the front side. The rotation range of the actuator 521 is
When the projection 34 overlaps the vertical movement space of FIG. 4 and the protruding piece 34 comes down to a predetermined position, the actuator 521 is rotated backward and the switch 52 is turned on. Switch 53
A hinge roller lever type actuator 531 is rotatably mounted on the switch body, and an on / off operation is performed by turning the actuator. The actuator 531 is mounted on the right side of the finger 2 so that the actuator 531 is on the upper side. . In the rotation range of the actuator 531,
The switch 53 is turned on when the vertical movement spaces of the projecting pieces 35 overlap and the projecting pieces 35 are lowered to the descending ends (when the plate 3 comes into contact with the upper surface of the cut portion of the finger 2).

As described above, the weight of the work placed on the auxiliary work for transportation 10 is converted into the amount of descent of the plate 3,
The spring constant of each compression coil spring 4 is set in accordance with the weight of the various workpieces to be transported in order to detect whether or not the lowering position has reached a preset several stages. When only the auxiliary work 10 for transport is placed on the plate 3 by the respective compression coil springs 4, the upper surface of the plate 3 is flush with the upper surface of the finger 2, and all the various works are placed on the auxiliary work 10 for transport. At this time, the lower surface of the plate 3 contacts the upper surface of the finger of the cutout 20. At this time, the compression coil spring 4 is in the maximum compression state,
Since the plate 3 is not lowered any more because it fits into the concave portion on the linear guide bearing 22 inside, no excessive compressive force is applied more than the total weight of the auxiliary work for transportation and the total work.

The discriminating device 6 is attached to a control device of a robot (not shown) to which the robot hand 1 is mounted, receives on / off signals from the contact sensors 32 attached to both fingers and the position detecting means 5, and is instructed by itself in advance. It is determined whether or not the signal conditions match. Based on the result of this determination, the determination device 6 sends an operation continuation or operation interruption signal to the robot controller.

The operation of this embodiment having such a configuration will be described with reference to FIGS. First, a robot (not shown), which has received an order from a customer through a keyboard operation or the like, moves to a place where the auxiliary work 10 for transport is placed, and the cylindrical part 101 of the auxiliary work 10 for transport is moved by the robot hand 1.
As shown in FIG. 2, the finger 2 is made to enter from the side just below the disk 102 in an open state, as shown in FIG. The finger 2 with respect to the cylindrical portion 101 is detected by a photo sensor (not shown) or the like.
Is detected, and the finger is stopped from entering at a position where the disk 102 does not hang on the upper surface on the base side of the finger 2. At this time, as shown in FIG. 3, the position of the center of gravity in the horizontal plane between the axes of the four guides 31 coincides with the axis of the auxiliary work 10 for transportation. After the entry is stopped, the finger 2 is closed, and the transporting auxiliary work 10 is sandwiched vertically slidably.

On the other hand, the auxiliary work for transportation 1
On top of 0, as shown in FIG.
A work A which is an ordered food or the like is placed. When the finger 2 holding the transporting auxiliary work 10 is vertically raised, only the finger 2 is lifted by the weight of the transporting auxiliary work 10 and the work A, and the contact sensor 3
2 detects the contact of the flange of the disk 102 of the auxiliary work 10 for transport, and the discriminating device 6 confirms the presence of the auxiliary work 10 for transport. When the ascent continues, the plate 3 starts to sink under the weight of the work A, and the compression coil springs 4 are compressed by a flexure dimension corresponding to the weight. The protruding piece 33 also moves down with the plate 3 which has moved down by the deflection size, and the switch 511 is turned on by rotating the actuator 511. At this time, the protruding pieces 34 and 35 do not rotate the corresponding actuators, and the switches 52 and 53 remain off. Based on the on / off information, the discriminating device 6 confirms the existence of the auxiliary work 10 for transport and the work A, and urges the robot controller (not shown) to proceed to the next operation. When the information is information other than the combination of the ON information of the contact sensor 32 and the switch 51 and the OFF information of the switches 52 and 53, the discriminating device 6 determines that the work A
The next operation of the robot is suspended because it is not placed on the top.

Next, a case where an order for a work B which is heavier than the work A is received will be described with reference to FIG. When the finger 2 enters and moves up in the same manner as in the case of the work A, each compression coil spring 4 is compressed with a larger deflection size than in the case of the work A. The protruding pieces 33 and 34 are also lowered with the plate 3 lowered by the deflection size, and the actuators 511 and 52
By turning 1, the switches 51 and 52 are turned on.
At this time, the protruding piece 35 does not rotate the corresponding actuator, and the switch 53 remains off. Based on the on / off information, the discriminating device 6 confirms the existence of the auxiliary work 10 for transportation and the work B, and urges the robot controller (not shown) to proceed to the next operation. If the information is other than the combination of the contact sensor 32, the ON information of the switches 51 and 52, and the OFF information of the switch 53, the discriminating device 6 determines that the work B is not placed on the auxiliary work for transport 10 and Suspend the operation.

Further, as shown in FIG.
When both orders are received, the operation of the finger 2 is the same, but each compression coil spring 4 is compressed with a flexure dimension corresponding to the combined weight of the work A and the work B. In this case, each compression coil spring 4 is pressed into the through hole 21, and the plate 3 contacts the upper surface of the cut portion of the finger 2. The protruding pieces 33, 34, 35 also move down with the plate 3, and the switches 51, 52, 53 are turned on by rotating the actuators 511, 521, 531. Based on these pieces of ON information, the discriminating device 6 confirms the existence of the auxiliary work 10 for transport and the works A and B, and urges the robot controller (not shown) to proceed to the next operation. Contact sensor 3
If the information is information other than the combination of the information 2 and the ON information of the switches 51, 52, and 53, the discriminating device 6 determines that the works A and B are not placed on the auxiliary work for transport 10 and suspends the next operation of the robot.

In any case, when the work placed on the auxiliary work 10 for transportation falls during the transportation, the plate 3 is lifted up by the lost weight due to the spring pressure of the compression coil spring 4. , The corresponding switch is turned off. When the change of the on / off information is transmitted from the position detecting means during the transportation, the robot (not shown) suspends the transportation operation, returns to the position of the work supply device (not shown), and supplies the lost work to resupply the lost work. Request to the device.

In this embodiment, the case of transporting two types of workpieces has been described. However, in the case of transporting more types of workpieces, the number of protruding pieces of the plate 3 and the number of switches with actuators as position detecting means are also required. Is increased and the setting of the spring constant of the compression coil spring 4 is changed. In this embodiment, a combination of a switch with an actuator and a dog is adopted as the position detecting means. However, as another means for detecting the relative positional relationship between the plate 3 and the finger 2, a mechanical displacement sensor or a photoelectric A method of attaching a displacement sensor to a finger, detecting the amount of displacement of the plate 3 or the guide 31, comparing the displacement data set in advance with the weight of various workpieces input to the discriminator, and detecting the mounting state is also easily adopted. It is possible.

[0021]

According to the present invention, the weight of various workpieces to be transported is converted into a relative position in the vertical direction with respect to the fingers of the plate, and the hand mounting state on the transporting auxiliary workpiece is detected by the hand itself. It is not necessary to equip the robot with a visual recognition device or to provide a separate visual recognition place. Further, it is possible to provide a robot hand that detects the loaded state of a plurality of works on the auxiliary work for transportation at a low cost without using an expensive weight sensor.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a robot hand according to the present invention.

FIG. 2 is a plan view showing a state in which the robot hand holds an auxiliary work for transportation.

FIG. 3 is a partially cutaway side view showing a state in which the robot hand holds an auxiliary work for transportation.

FIG. 4 is a side view showing a state in which the robot hand carries a workpiece.

FIG. 5 is a side view showing a state in which different works are transported.

FIG. 6 is a side view showing a state of transporting a plurality of works.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Robot hand 10 Auxiliary work for conveyance 102 Disk (flange) 101 Cylindrical part (part below flange) 2 Finger 3 Plate 4 Compression coil spring (elastic body) 5 Position detecting means A, B Various works 6 Discrimination device (discrimination) means)

Claims (1)

(57) [Claims] 1. A pair of left and right fingers for gripping a portion below a flange of a transport auxiliary work having a flange at an upper portion with a gripping finger and holding the transport auxiliary work to such an extent that the auxiliary work can be moved up and down. A pair of left and right plates that are vertically movably fitted to the upper surface of each of the fingers and that support the lower surface of the flange portion of the auxiliary work for transport; and an elastic body that is inserted between the plate and the fingers and urges the plate upward. And a position detecting means provided on each of the fingers, for detecting the elevating state of the plate with respect to the upper surface of the finger; height information of the plate detected by the position detecting means; A determination unit configured to compare the data with the data and determine whether a predetermined work is placed on the auxiliary work for transport.