JPH0241294B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a robot hand for harvesting fruits such as tangerines and apples. As such a robot hand for harvesting, the present applicant previously proposed one having the following configuration. That is, a plurality of finger members are arranged in a circumferential manner on a base frame connected to the tip of the arm, and the finger members are extended to form an introduction path for the harvested object between them. This is a harvesting robot hand configured to be able to freely switch between a bent position and a bent position in which it is bent inward to support an object to be harvested.

The harvesting robot hand holds an object to be harvested, such as a fruit, with its finger members, and in this state, a handle-like part (in the case of fruits, it is called a peduncle) attaches the object to be harvested to a branch. ) to harvest by cutting with a cutter, or to harvest by separating the handle and the object to be harvested while operating the arm or base frame so as to bend or pull the handle. become.

Conventionally, the finger members are configured to elastically return to the extended position using an elastic member such as rubber, and a ring-shaped wire is provided to pass through the tip of each finger member, and the wire is pulled. An actuator was provided for switching the finger member to a bent position by tensioning the finger member.

According to the conventional configuration, when the robot hand approaches the object to be harvested, there is a risk that the wire may get caught on a branch or the like, and furthermore, one actuator that pulls the wire can handle all the Since the finger members are operated in a bent position, if even one of the finger members comes into contact with an obstacle such as a branch and is prevented from bending, all the finger members will be prevented from bending. However, there is a risk that the harvested object may be held incorrectly, and furthermore, the actuator requires a mounting space, which makes it difficult to make it compact.

In order to eliminate this inconvenience, the following configuration can be considered.

As shown in FIG. 5, a hollow elastic member 22 such as a coil spring for returning to an upright posture, the whole of which is covered with a flexible member 21 such as rubber, is erected around the base frame 9, and the inner surface thereof 21a so as to return to the bent position by heating with electricity from the external power source E.
A Ni-Ti based shape memory alloy 23 which has shape memory in advance is fixed thereto.

Then, the finger members 11 are driven to bend and extend by heating with electricity from the power source E and natural cooling by cutting off the electricity. Note that 24 is a wiring member for extracting fruit contact information from the contact sensor C fixed to the tip 11a of the finger member 11 to the outside.

With this configuration, there is no need to provide a wire that passes through the tip of each finger member, so there is no problem of the wire getting caught on a branch, etc., and each finger member is independent. Since the posture is switched between the flexion and extension postures, even if one finger member is prevented from flexing due to an obstacle, the flexion of the other finger members will not be affected. Since there is no need to install an actuator, the device can be made more compact.

Therefore, the above-mentioned conventional drawbacks can be overcome, but this configuration also has the following disadvantages:
Further improvement is desired.

That is, the finger member 11 described above includes only the shape memory alloy 23 for bending, and returns to the extended position due to the action of the elastic member 23 such as the coil spring.

However, since it takes time for the shape memory alloy 23 to cool naturally and return to the extended position due to the biasing force of the elastic member 23, the finger member 11 has the disadvantage that the response when returning to the extended position is extremely slow. However, further improvement is desired.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to take advantage of the advantage of bending and stretching the finger members using a shape memory alloy, while also making it possible to respond to both the bending and extension of the finger members. The point is to make it easier to perform.

The characteristic configuration of the harvesting robot hand according to the present invention is such that the finger members are made of a bending shape memory alloy whose shape is memorized in advance so as to return to the bent position when heated, and the finger members are made of a shape memory alloy for bending which has a shape memorized in advance so as to return to the bent position when heated; It is equipped with a shape memory alloy for elongation which has been previously stored in shape so as to return to its original state, and its functions and effects are as follows.

That is, by heating the bending shape memory alloy, the finger members can be bent to hold the harvested object. Then, when releasing the crop, the finger members can be elongated by heating the shape memory alloy for elongation. In other words, in both bending and extension of the finger members,
By utilizing the restoring force of the shape memory alloy, switching to the bent posture and switching to the extended posture can be performed with good responsiveness.

Therefore, by using a shape memory alloy, it is possible to switch between a bent position and an extended position with good responsiveness, while avoiding the drawbacks of the conventional structure using wires and actuators, thereby increasing the efficiency of harvesting operations. It has become possible to improve the

Embodiments of the present invention will be described below based on the drawings.

As shown in FIG. 1, a pair of left and right propulsion wheels 1,
A swivel base 5 that is driven and rotatable by an electric motor 4 is attached to a vehicle body equipped with a pair of front and rear idle wheels 2 and a plurality of outriggers 3 that can be raised and lowered, and a lift device A that can be raised and lowered is rotated. At the same time, the robot hand B for fruit harvesting is attached to the upper end of the lift device A,
A fruit harvesting machine is configured.

The lift device A includes a screw member 7 that is rotatably driven by an electric motor or the like and drives the base end of the arm 6 up and down, and guide members 8 and 8 for an up-and-down trajectory. The arm 6 is configured to move up and down.

To configure the fruit harvesting robot hand B, as shown in FIGS. 1 to 4, a lift device A is used.
A first arm 6a that can be vertically swung relative to the arm 6a, a second arm 6b that can be swung vertically relative to the arm 6a, and a third arm 6c that can be swung vertically relative to the arm 6b. A cylindrical case 9 for taking in fruits is provided as a base frame.
A bifurcated support frame 10 is pivotally supported to be freely swingable around a horizontal axis X, and a forked support frame 10 is pivotally supported to be freely rotatable around an axis Y along the longitudinal direction of the arm at the tip of the third arm 6c. A plurality of finger members 11 that can be freely bent and extended to support the fruits to be harvested in a state where they are pulled and moved inside the cylindrical case 9 are erected on the periphery of the opening of the case 9, and also on the side of the cylindrical case. A plurality of stem pressing members 12, which can be freely switched between a state in which they are retracted and a state in which they protrude from the case 9 so as to cover the fruit to be harvested, are arranged in the circumferential direction of the case 9, and are arranged in a circumferential direction of the case 9, so that the fruit to be harvested and the branches can be pressed. The handle-like part that connects the fruit stem, the so-called arc-shaped cutter 1 that cuts the stem.
3, and the fruit stem pressing member 1 with both ends as fulcrums.
2 and is pivotally connected to the case 9 so as to be movable in and out of the case 9.

Incidentally, as shown in FIG. 5, the finger member 11 is
The tip portion 11a is formed as a contact sensor C, and is configured to be able to collect information for horizontally moving the case 9 away from the fruit when it comes into contact with the fruit.

That is, the fruit intake cylindrical case 9 is maintained in an upward position by its own weight.

Then, by operating the multi-joint arm 6 or operating the lift device A, the cylindrical case 9 is moved upward from a position below the target fruit to a height suitable for harvesting the fruit, and at the same time, during the upward movement, the contact sensor C is activated. Based on the detected information, the fruit is corrected to be located at the center of the opening of the cylindrical case 9, and the finger members 11 are bent and driven inward of the case 9 to pull and move the target fruit. After that, the member for pressing the fruit 1
After operating the cutter 2 and the cutter 13 to cover the fruit to be harvested, the cutter 13 is operated to cut the stem and collect the harvested fruit.

One end of each pressing member 12, which is formed by bending an elastic wire such as a wire into an arc shape, is pivotally supported on the inner surface of the case 9, and the other end of the pressing member 12 extends through the case 9. It is pivoted and
By using both ends of the kerat pressing member 12 as supporting parts and rotating the member 12 about its fulcrum, it can move in and out of the case 9.

In order to move the fruit stem pressing member 12 into and out of the case 9, the case 9 is moved between the inner cylinder 9a and the outer cylinder 9.
b, and the inner cylinder 9a and the outer cylinder 9b are fitted and supported in a relatively rotatable state around the vertical axis Z, and the vertical direction in which the tip of the other end of the pedestal pressing member 12 engages. The slit 14 along the outer cylinder 9
b, and is further provided with an air cylinder 15 that rotationally drives the outer cylinder 7b by a link, so that the pedestal pressing member 12 can be moved in and out of the case 9 as the outer cylinder 7b is rotated in the forward and reverse directions. It is configured to move.

The cutter 13 has concave blade portions 16 and 16' at the center in the longitudinal direction, and has a pair of arcuate band-shaped blades 1 that are moved relative to each other in the longitudinal direction to perform a cutting action.
7, 17' are provided. Both ends of the cutter 13 are pivotally attached around an axis Q along the radial direction of the case 9, and a link 18 is fixed to one end side, and a link 18 is fixed to the tip of this link 18 to press the fruit stem. An engaging pin 19 that engages with the slit 14 in the same manner as the member 12 for pressing is provided, and by rotationally driving the outer cylinder 9b, the member 12 for pressing the fruit stem can be swung in and out of the case 9. The cutter 13 is formed at the center of the upper part of the case 9 by intersecting the pressing portion 12c of the kerat pressing member 12. After positioning and holding the kerat in _S1 , the blade portions 16, 16 ′ is configured to cut the fruit stem.

To support the pair of blade bodies 17, 17' relatively movably, a link 18 pivotally supports both ends of the outer blade body 17 and engages with one end of the inner blade body 17'. This link 18 is connected to the air cylinder 2.
0 in the vertical direction, the inner blade 17' is moved relative to the outer blade 17.
can be moved in its longitudinal direction. Then, by operating the air cylinder 20, the fruit stem positioned at the concave portion of the blade portions 16, 16', that is, the gap _S1 formed at the center of the case 9 is cut.

The finger members 11 are in an extended position (sometimes referred to as an upright position in the following description) in which they are extended to form an introduction path for the harvested object between them;
It is configured to be able to switch freely between a bent position bent inward to support the harvested object, and more specifically, the entire structure is made of a medium flexible member 21, and the outside of the case 9 inside thereof is constructed as a whole. On the side surface 21b, a shape memory alloy 23a that remembers the shape to be restored to an upright position by heating with electricity from a power source E is installed, and the case 9
A shape memory alloy 23b is provided on the inner surface side 21c, and has a shape memory that stores the shape of the case 9 to be restored to the inwardly bent position when heated by the power source E.
By alternately heating the two shape memory alloys 23a and 23b with electricity, the finger member 11 is bent and stretched. Note that 24 is a wiring member for extracting to the outside information on contact with the fruit from the contact sensor C fixed to the tip portion 11a of the finger member 11.

Incidentally, when using the fruit harvesting machine having the above-mentioned configuration, for example, as shown in FIG. For remote control, it would be more convenient to include a control device that automatically operates the robot hand B based on a starting operation command while confirming the position of the target fruit using a distance measuring device or the like.

Furthermore, in that case, as shown in FIG. 2, the bifurcated support frame 10 is rotationally driven around the axis Y of the arm 6c by a motor 24 equipped with an electromagnetic clutch and an encoder for detecting the rotation status. At the same time, the case 9 is rotated around the axis X by a motor 25 and a chain 26, which are similarly equipped with an electromagnetic clutch and an encoder, and the direction of the case 9 relative to the fruit is adjusted to approach the target fruit. It is a good idea to do so. When the clutches of the motors 24 and 25 are disengaged when the case 9 reaches the target position, the case 9 is automatically maintained in an upward position by its own weight, as described above. .

In addition, the fruit stem pressing member 12 may be formed in an arc shape using an elastic wire such as a wire, or may be formed in a curved plate shape. Further, the pressing portion 12c may be covered with a flexible member such as rubber to protect the fruit from damage, and the specific structure of the peduncle pressing member 12 can be modified in various ways.

Furthermore, the structure for moving the fruit stem pressing member 12 in and out of the case 9 can be achieved by relatively rotating the inner cylinder 9a and the outer cylinder 9b of the case 9 by linking with the air cylinder 15, or by directly using a motor or the like. It may be rotated. Furthermore, in addition to moving the fruit stem pressing member 12 forward and backward by engagement with the end tip and the slit 14 of the outer cylinder 9b, a gear is provided on one of each support part of the fruit stem pressing member 12, and the outer cylinder A rack may be provided on the rack 9b, and the direct pressing member 12 may be moved in and out by rotating around its support, and various modifications can be made.

Further, each of the pressing portions 12c at the tip of each kerat pressing member 12 is formed into a curved plate shape with a large width along the circumferential direction, and in the protruding state, the pressing portions 12c are formed by crossing the pressing portions 12c. The time for passing through the fruit stalks〓
The structure may be such that the fruit is covered from the top with _S1 remaining.

Further, the cutter 13 can have various configurations, and may be provided independently in addition to being used as a member for pressing the fruit stem as shown in this embodiment. Further, the driving structure thereof may be driven not only by the air cylinder 20 but also by a motor and a link, and various changes can be made.

In addition, in the embodiment, the cylindrical case 9 is formed into a cylindrical shape with a bottom, and this case 9 is used to release the fruit to be harvested.
Although the case 9 is designed to be discharged in the opposite direction, the case 9 may be formed into a cylindrical shape passing through the top and bottom and provided with a chute so that the fruit is automatically discharged after cutting the stem.

[Brief explanation of the drawing]

The drawings show an embodiment of the robot hand for harvesting according to the present invention, and FIG. 1 is an overall side view of the fruit harvesting machine;
FIG. 2 is a plan view of the hand, FIG. 3 is a side sectional view of the hand, and FIG. 4 is an explanatory diagram of cutting the fruit stalk. FIG. 5 is a side sectional view showing a comparative structure of the finger member. 6th
The figure is a side sectional view showing the finger member of the present invention. 6... Arm, 9... Base frame, 11... Finger member,
22...Elastic member, 23b...Shape memory alloy for bending, 23a...Shape memory alloy for elongation.

Claims (1)

[Claims] 1 A plurality of finger members 11 are arranged in a circumferential manner on a base frame 9 connected to the tip of the arm 6, and these finger members 11 are extended to form an introduction path for the harvested object between them. A harvesting robot hand configured to be able to freely switch between an extended posture and a bent posture bent inward to support an object to be harvested,
The finger member 11 includes a bending shape memory alloy 23b whose shape is stored in advance so as to return to the bent position when heated, and a shape memory alloy 23b whose shape is stored in advance so as to return to the extended position when heated. A harvesting robot hand comprising a shape memory alloy 23a for elongation.