CN101518903B - Crank block type under-actuated robot finger device - Google Patents

Abstract

A crank slider type underactuated robot finger device belongs to the technical field of anthropomorphic robot hands. The device includes a first finger segment, a second finger segment and an underactuated joint, and the underactuated joint includes an active slider, a joint shaft, a spring, a first shaft, a connecting rod, a second shaft and a dial. The spring connects the first finger segment and the active slider, the connecting rod is respectively hinged with the active slider and the dial, the dial is sleeved and fixed on the joint shaft, and the active slider is embedded in the first finger segment. The device adopts the slider crank mechanism to realize the rotation function of the second finger segment. After a reasonable size design, the short movement distance of the active slider can bring about a large-angle rotation of the second finger segment. The device can cooperate with other active fingers or active joints to grab objects, and is self-adaptive, with few transmission parts, short transmission chain, low cost, similar shape to human fingers, and can be connected in series to form multi-joint fingers with high and low actuation. for anthropomorphic robotic hands.

Description

Slider crank underactuated robotic finger device

technical field

The invention belongs to the technical field of anthropomorphic robot hands, and in particular relates to the structural design of a crank slider type underactuated robot finger device.

Background technique

Similar to humans, most functions of anthropomorphic robots are realized through hand manipulation, so the hand structure is an important part of anthropomorphic robots, and its design is one of the key technologies of anthropomorphic robots. In order to increase the anthropomorphism of the hand, more joint degrees of freedom should be designed for the hand. However, in order to reduce the control difficulty of the anthropomorphic robot hand, as well as reduce the volume and weight of the hand, it is necessary to reduce the number of drivers. Certain contradictions, in addition, in order to better grasp the object, it is also necessary for the finger to have a certain degree of adaptability when grasping the object. Designing an underactuated robotic finger device can better achieve the three goals of more joint degrees of freedom, fewer actuators, and strong adaptability when grasping objects of different shapes and sizes.

An existing rack-type underactuated mechanical finger device, such as the Chinese invention patent CN 1410223A, includes a first finger segment, an underactuated joint and a second finger segment, and the underactuated joint contains an active slider, a joint shaft and gear teeth article organization. External force drives the active slider to slide on the first finger segment, and at the same time, the rack fixed on the active slider moves in the first finger segment, driving the gear meshed with the rack to rotate around the joint axis to realize the rotation of the second finger segment and fasten the object.

The weak point of this device is: this device adopts rack and pinion drive, and device is more complicated, and the mass of finger is bigger, and energy consumption is higher. In order to achieve a good under-actuation effect, that is, to achieve a large angle of rotation of the second finger segment, the gear used must have a small radius, which is difficult to process and high in cost. Moreover, the rack and pinion mechanism needs good lubrication and sealing, and the use cost is relatively high.

An existing connecting rod underactuated mechanical finger device, such as Chinese invention patent CN 100450732C, contains a first finger segment, a second finger segment and an underactuated joint arranged between the two. The underactuated joint includes a joint shaft, an active slider, a link mechanism, and a torsion spring; the link mechanism includes an active rod and a driven rod. The other end of the rod is hinged with the second finger section; the active slider is embedded in the first finger section and is in contact with the active rod; the torsion spring is sleeved on the joint shaft, one end is fixedly connected with the first finger section, and the other end is connected with the first finger section. The second finger segment is fixed. The external force drives the active slider to slide in the first finger segment, and the active slider pushes the active link, and through the driven link, drives the second finger segment to rotate around the joint axis and fasten the object.

The disadvantages of this device are: the device uses multiple connecting rods to drive, there are many transmission parts, the transmission chain is long, the device is relatively complicated, and there is a line contact between the active slider and the active connecting rod, the mechanical impact is large, and the contact stress is large. , easy to wear and poor reliability.

Contents of the invention

The purpose of the present invention is to propose a crank slider type underactuated robot finger device in order to overcome the deficiencies of the prior art. The device can cooperate with other actively driven fingers or other actively driven joints on the fingers to grasp objects, and has an adaptive function to the shape and size of the grasped objects. The device has fewer transmission parts, short transmission chains, simple structure, and small size Small, thereby further reducing processing difficulty and maintenance costs, making the shape of the mechanical finger more similar to that of a human finger.

The present invention adopts following technical scheme:

A crank-slider type underactuated robot single-joint finger device according to the present invention includes a first finger section, a second finger section and an underactuated joint arranged between them, and the underactuated joint includes an active slider block, joint shaft and spring; the joint shaft sleeve is set in the first finger segment, the second finger segment is sleeved on the joint shaft, the spring is set in the first finger segment, and the two springs The ends are respectively connected to the first finger segment and the active slider; it is characterized in that: the under-actuated joint also includes a first shaft, a connecting rod, a second shaft and a dial; one end of the connecting rod and the active slider pass through The first shaft is hinged, and the other end is hinged with the dial through the second shaft; the dial is sleeved on the joint shaft; the centerline of the first shaft and the second shaft are parallel to the centerline of the joint shaft; the active The slider is embedded in the first finger segment.

The slider crank type underactuated robot single-joint finger device according to the present invention is characterized in that: the structural parameters of each part of the underactuated joint conform to the following relationship: let the length of the connecting rod be L, and the center line of the joint axis to the first The distance between the centerlines of the two axes is R, then: L:R=2.5～3.5:1.

The slider crank type underactuated robot single-joint finger device according to the present invention is characterized in that: the joint axis is composed of a left joint semi-axis and a right joint semi-axis, and the left joint semi-axis and the right joint semi-axis The coaxial sleeve is arranged in the first finger section.

The present invention also provides a crank slider type underactuated robot multi-joint finger device using the crank slider type underactuated robot single-joint finger device, which is characterized in that it includes n finger segments and n-1 said The underactuated joint of , where n is an integer greater than 2.

Compared with the prior art, the present invention has the following advantages and outstanding effects:

The device of the present invention realizes the rotation function of the second finger segment by using the crank slider mechanism. After reasonable size design, the very short movement distance of the active slider can bring the rotation of the second finger segment at a large angle; the device of the present invention can cooperate with other active The driven finger or other active drive joints on the finger can grasp the object, and has an adaptive function to the shape and size of the grasped object, which reduces the requirements of the control system; The chain is short, the structure is simple and reliable, the size is small, the processing cost is low, easy to maintain, and the shape is similar to the fingers of a human hand. The device can be used as a finger or a part of a humanoid robot hand, and can also be connected in series to form a highly shape-adaptive and highly underactuated finger, and can also be combined with a plurality of such highly underactuated fingers to form a highly underactuated anthropomorphic robot The hand is used to achieve the excellent effect of high joint freedom and high adaptability of the anthropomorphic robot hand.

Description of drawings

Fig. 1 is a front view of an embodiment of a crank-slider type underactuated robot single-joint finger device provided by the present invention.

Fig. 2 is a left side view of Fig. 1 .

FIG. 3 is a right sectional view of FIG. 1 , that is, a B-B sectional view of FIG. 4 .

FIG. 4 is a cross-sectional view of FIG. 1 , that is, a cross-sectional view along A-A of FIG. 3 .

Fig. 5 is an external view of the left support plate.

Figure 6 is the external view of the active slider.

Fig. 7 is an external view of the dial and the joint shaft.

Fig. 8 is a right sectional view of Fig. 1 (at this moment, the active slider is in the middle position of the stroke, and the second finger section has rotated an angle).

Fig. 9 is a right sectional view of Fig. 1 (at this time, the active slider moves to a position close to its stroke limit, and the second finger section has rotated a larger angle).

10 , 11 , 12 , and 13 are schematic diagrams of objects grasped by fingers in this embodiment with the first finger segment fixed on the palm.

Figures 14, 15, 16 and 17 are schematic diagrams of objects grasped by the fingers of this embodiment after the first finger segment is connected to the active joint.

Fig. 18 is a front view of an embodiment of the slider crank type underactuated robot multi-joint finger device (using two underactuated joints) of the embodiment shown in Fig. 1 .

FIG. 19 is a left side view of the bi-articulated finger of FIG. 18 .

Fig. 20 is a schematic diagram of the double-jointed finger grasping a large-sized object under the rotation of two underactuated joints in the embodiment of Fig. 18, and the root finger segment is connected with the active joint.

FIG. 21 is a schematic diagram of a three-finger grasping object using the embodiment of three double-jointed fingers shown in FIG. 18 .

Fig. 22 is a left side view of Fig. 21 .

In Figures 1 to 22:

1. The first finger section, 11. The support, 12. The left support plate,

121. Lug on first finger segment, 13. Right support plate, 14. Back panel,

2. Second finger segment, 3. Underactuated joint, 4. Active slider,

41. Cover plate, 42. Groove on the active slider, 5. Connecting rod,

6. Dial, 7. Joint shaft, 71. Left joint half shaft,

72. Right joint half axis, 8. Spring, 91. First axis,

92. Second axis, 93. Middle finger segment.

Detailed ways

The specific structure, working principle and working process of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

An embodiment of a crank-slider type underactuated robot single-joint finger device designed by the present invention, the appearance is shown in Figures 1 and 2, the cross-sectional views are shown in Figures 3 and 4, and some parts are shown in Figures 5, 6 and 7 , the action principles are shown in Figures 8, 9, 10, 11, 12, 13, 14, 15, 16, and 17. This embodiment includes a first finger section 1, a second finger section 2 and an underactuated joint 3 arranged between the two, the underactuated joint includes an active slider 4, a joint shaft 7 and a spring 8; the described The joint shaft 7 is sleeved in the first finger segment 1, the second finger segment 2 is sleeved on the joint shaft 7, the spring 8 is arranged in the first finger segment 1, and the two ends of the spring 8 are respectively connected The first finger section 1 and the active slider 4; it is characterized in that: the under-actuated joint 3 also includes a first shaft 91, a connecting rod 5, a second shaft 92 and a dial 6; one end of the connecting rod 5 It is hinged with the active slider 4 through the first shaft 91, and the other end is hinged with the dial 6 through the second shaft 82; the dial 6 is sleeved on the joint shaft 4; the center line of the first shaft 91 and the center of the second shaft 92 The line is parallel to the centerline of the joint axis 7; the active slider 4 is embedded in the first finger segment 1.

In this embodiment, the joint shaft 7 is composed of a left joint half shaft 71 and a right joint half shaft 72, and the left joint half shaft 71 and the right joint half shaft 72 are coaxially sleeved in the first finger segment 1 .

In this embodiment, in order to better realize the underactuated function of the large-angle rotation of the second finger section 2 caused by the small displacement of the active slider 4, the structural parameters of each part of the underactuated joint 3 conform to the following relationship Assuming that the length of connecting rod 5 is L (that is, the distance from the center line of the first shaft 91 to the center line of the second shaft 92 is the length of the connecting rod 5), the center line of the joint shaft 7 to the center line of the second shaft 92 The distance is R, then: L:R=2.5～3.5:1.

The present invention also provides a crank slider type underactuated robot multi-joint finger device using the crank slider type underactuated robot single-joint finger device, which is characterized in that it includes n finger segments and n-1 said The underactuated joint of , where n is an integer greater than 2.

In this embodiment, the first finger segment 1 includes a support 11 , a left support plate 12 , a right support plate 13 and a back plate 14 . The first finger section 1 forms a hollow container shape, and there is a projection 121 (as shown in Figure 5 ) on the left support plate 12, and the active slider 4 is provided with a groove 42 on the active slider that does not pass through (as shown in Figure 5 ). As shown in Figure 6), the protrusion 121 is inserted into the groove 42 on the active slider, and this part of the structure plays the role of limiting the sliding direction of the active slider 4 and preventing the active slider 4 from breaking away from the first finger section 1, that is, To the role of positioning and guiding, to ensure that the direction of motion of the active slider 4 is along the direction of the chute of the active slider. As shown in Figure 7, the dial 6 can be composed of two partially hollow wheels, the two wheels are fixed at the edges, and there is no shaft in the middle, so that the connecting rod 5 can pass through the dial 6 during the movement.

Rivets can be used for the first and second shafts.

The surface of the active slider 4 is also covered with a cover plate 41. The surface of the cover plate can also be covered with a suitable elastic industrial rubber material. In this way, when grasping an object, a soft finger-surface contact will be formed between the surface of the finger and the object. On the one hand, the degree of constraint of the finger on the object is increased, and on the other hand, the friction force can be increased, thereby increasing the stability of the grasped object.

The function of the spring 8 is: in the natural state and when the object is released, the spring 8 pushes the active slider 4 to the outside of the finger, and under the action of the connecting rod 5 and the dial 6, the second finger segment 2 is pushed to the vertical position. Straight, that is, keep the fingers straight; when grabbing an object, the spring 8 will be deformed under the push of the foreign object.

A double-joint finger embodiment of a crank-slider type underactuated robot multi-joint finger device includes three finger segments and two underactuated joints, as shown in Figures 18 and 19.

The working principle of the embodiment of the single-joint finger device shown in FIG. 1 will be described below with reference to the accompanying drawings.

(a). If the first finger section 1 of the present embodiment is fixed on the palm of the humanoid robot hand, the working principle of the present embodiment, as shown in Figures 10, 11, 12, and 13, is described as follows:

When the robot hand does not touch the object, the fingers are in a free state. At this time, the spring 8 prevents the second finger segment 2 from rotating, and the fingers remain straight.

When the robot hand grabs an object, the other fingers rotate and press the object, the object squeezes the active slider 4, and the active slider moves a certain displacement d in the first finger segment 1 along the direction perpendicular to the surface of the finger, through the connecting rod 5 and The transmission of the dial 6 drives the second finger section 2 to make a large rotation angle α around the center line of the joint axis 7 until the second finger section 2 touches the object, so the robot hand will have automatic adaptability to the size and shape of the object . This makes the second finger section rotate as if it is driven by a driver such as a motor, and can fast hold objects, realizing the purpose that the finger itself can have multiple joint degrees of freedom without using a driver.

When the robot hand releases the object, the other fingers leave the object under the rotation of the motor, and the object no longer presses the active slider 4, and the spring 8 will push the active slider to the outside of the finger, through the connection between the connecting rod 5 and the dial 6 The transmission drives the second finger segment 2 to turn back to the initial position around the center line of the joint axis 7 .

(b). If the root of the first finger section 1 of this embodiment (the embodiment shown in Figure 1) is socketed on an active joint driven by a driver, the working principle of this embodiment is as shown in Figures 14, 15, and 16 , 17, described as follows:

When the robot hand grabs an object, the active joint covered with the first finger segment 1 rotates under the action of the driving torque m, so that the entire underactuated finger rotates around the active joint at the root until the active slider 4 touches the object. Can not leave under the action of finger, so, when active joint continues to rotate, active slide block 4 translates toward the first finger segment 1 along the direction perpendicular to finger surface under the blocking extrusion of object, and thereafter grabbing process and (a )similar.

The embodiment of the underactuated double-joint finger applying the embodiment shown in FIG. 1 is shown in FIGS. 18 and 19 . The underactuated two-joint finger is composed of a first finger segment 1 , a middle finger segment 93 , a second finger segment 2 and two underactuated joints 3 . The principle of the underactuated double-joint finger using two underactuated joints to rotate and grasp an object is shown in FIG. 20 . When the robot hand grabs an object, the two underactuated joints will move sequentially, and finally automatically adapt to the shape and size of the object. It is as if the finger is actively driven by a motor at the underactuated joint. The three-fingered robot hand applying the embodiment shown in FIG. 1 is shown in FIGS. 21 and 22 .

Claims (4)

1. a slider crank type underactuated robot single-joint finger device, comprising a first finger segment (1), a second finger segment (2) and an underactuated joint (3) arranged between the two, described The underactuated joint includes an active slider (4), a joint shaft (7) and a spring (8); the joint shaft is sleeved in the first finger segment, and the second finger segment is sleeved on the joint shaft, The spring is arranged in the first finger segment, and the two ends of the spring are respectively connected to the first finger segment and the active slider; it is characterized in that: the underactuated joint also includes a first shaft (91), a connecting rod (5 ), the second shaft (92) and the dial (6); one end of the connecting rod is hinged with the active slider through the first shaft, and the other end is hinged with the dial through the second shaft; the dial is sleeved on the joint shaft Above; the centerline of the first axis, the centerline of the second axis are parallel to the centerline of the joint axis; the active slider is embedded in the first finger segment. 2. the slider crank type underactuated robot single-joint finger device as claimed in claim 1, is characterized in that: the structural parameters of each part of the underactuated joint meet the following relationship: assuming that the connecting rod length is L, the joint axis The distance from the centerline to the centerline of the second axis is R, then: L:R=2.5～3.5:1. 3. The slider crank type underactuated robot single-joint finger device as claimed in claim 1 or 2, characterized in that: the joint axis (7) is composed of a left joint semi-axis (71) and a right joint semi-axis (72) ), the left joint semi-axis and the right joint semi-axis are coaxially sleeved in the first finger segment. 4. A slider-crank type underactuated robot multi-joint finger device adopting the device according to claim 1, is characterized in that: comprise n finger segments and n-1 described underactuated joints, wherein n is greater than Integer of 2.

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