CN108189055B - Rack cosine telescopic straight-line parallel clamping self-adaptive finger device - Google Patents

Abstract

A rack cosine telescopic linear flat clip adaptive finger device belongs to the technical field of robotic hands, and includes a base, two finger segments, two joint shafts, a driver, a plurality of connecting rods, a transmission mechanism, a spring element, and the like. The device realizes the functions of straight-parallel gripping and adaptive grasping of robot fingers. According to the different shapes and positions of objects, the device can maintain the posture of the second finger segment and move the second finger segment linearly to grip the object, and can also automatically rotate the second finger segment to contact the object after the first finger segment touches the object. , to achieve the purpose of adaptively wrapping objects of different shapes and sizes; the grasping range is large, and the grasping is stable and reliable; one driver is used to drive two finger segments; the device has simple structure, low processing, assembly and maintenance costs, and is suitable for robotic hands. .

Description

Rack cosine telescopic linear flat clip adaptive finger device

technical field

The invention belongs to the technical field of robot hands, and particularly relates to a structural design of a rack cosine telescopic straight-line flat clip adaptive finger device.

Background technique

With the development of intelligent technology, robotics has become a research hotspot, and robotic hands have attracted more and more attention, and more and more research achievements have been made in this area. In order to assist robots to complete more tasks in special situations, a variety of robot hands have been developed, such as dexterous hands, special hands, pincer hands (industrial grippers), etc. Objects in space are various and of different sizes, such as thin paper, irregularly shaped stones, larger spheres, etc. Objects have six degrees of freedom, and the robot hand needs to limit the six degrees of freedom of the object while grasping the object to hold the object stably. In order to assist the robot to complete more tasks, the robot hand needs to be able to adapt to grasp a variety of objects of different shapes and sizes to the greatest extent.

To this end, a variety of robotic hands have been developed, such as dexterous hands, specialized hands, pincer hands (industrial grippers), and the like. It has always been the common goal of scientists to develop a robotic hand that can be as flexible as a human hand, can grasp a variety of objects, and complete various tasks. The research on robotic hands began to focus on dexterous hands. Each finger joint is equipped with a driver, but the control is complex and the gripping force is small, which greatly limits the application of dexterous hands.

Adapting to object surface grasping mainly adopts the method that the force on the surface of the object by each finger surface and the external force received by the object achieve a mechanical balance, and then the object reaches a static equilibrium state, so that the object is stationary, thereby realizing the grasping of the object. The force on the object depends on the force on the contact surface between the object and the finger and the external force on the object. Since there is no need to balance the process of large friction force and the external force received by the object, the force of each finger surface on the surface of the object in the grasping mode of the object surface is much smaller than the force of the industrial gripper on the surface of the object, which is suitable for grasping the surface of the object. Fetch is also known as power grab.

The adaptive grasping mode refers to the grasping mode that uses flexible joints or springs and other components to enable each finger segment of the robot finger to move relative to the surface of the object when grasping the object, so as to achieve the effect of adaptively grasping the object surface envelope, such as The SARAH hand and the Southampton hand use the adaptive grasping mode.

Existing dexterous and underactuated hands can achieve adaptive surface grasping patterns. Although the dexterous hand has a high degree of anthropomorphism during the action process and can complete the grasping of the surface of the object, its cost is high, the control is complicated, and it needs frequent maintenance. The driving force generated by the existing dexterous hand joint drivers (such as motors, air muscles, etc.) is relatively small, and the movement of each finger segment of the dexterous hand is directly driven by the dexterous hand joint driver, which makes the dexterous hand load capacity weaker, which makes the dexterous hand. Can not be widely put into production practice and daily life.

For this reason, the underactuated anthropomorphic robot hand came into being. The underactuated hand is a robot hand with fewer actuators than the joint degrees of freedom. The theory of underactuated robot hand and a classic four-link-spring were proposed earlier by Laval University in Canada. Structure of an underactuated robotic hand. Theory and practice have proved that the underactuated robot hand has high application value due to less drives, simple control, large grasping force and compact structure. Since then, a large number of research results on underactuated hands have emerged, and underactuated hands have also been put into production practice in large numbers.

For example, an existing underactuated two-joint robot finger device (Chinese invention patent CN101234489A) includes a base, a motor, a middle finger segment, an end finger segment and a parallel pulley transmission mechanism. The device realizes the special effect of double-joint underactuated fingers bending and grasping objects, and is self-adaptive. The disadvantage of the underactuated mechanical finger device is that the fingers are always in a straight state before touching the object, and the grasping method is mainly a grasping method, so it is difficult to achieve a better end-parallel grasping effect. However, for small objects, due to the small surface of the object, and the length of each finger segment of the underactuated robot finger is too long relative to the surface of the object, it is difficult to adapt to the surface of the object. The advantages.

Robotic hands with linear translation gripping have been invented, such as patent WO2016063314A1, including several links, a gripping finger segment, and a driver. The device can realize the linear translation of the clamping finger segment, and realize the function of parallel clamping for objects of different sizes by using the parallel movement of the clamping finger segment. The disadvantage is that the device can only realize the function of straight-line and parallel clamping, and cannot realize the function of grasping objects with an adaptive envelope.

Conventional underactuated hands with two grasping modes have been developed. An existing underactuated finger, such as US Pat. No. 8,973,958B2, includes five links, springs, mechanical restraints, and actuators. The device realizes arc parallel clamping and adaptive grasping mode. When working, at the initial stage, the posture of the terminal finger segment relative to the base is maintained to perform a near-joint bending action, and then the function of parallel gripping or adaptive envelope gripping can be realized according to the position of the object. The disadvantage is that (1) the device can only realize the arc parallel clamping function, but cannot realize the linear parallel clamping function. When clamping thin plate objects of different sizes on the worktable, the robot arm needs to move to cooperate to realize the grasping function. Therefore, there is a serious shortage of grasping; (2) the device adopts a multi-link mechanism, which has a large dead zone in motion and a small grasping range.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a rack cosine telescopic straight-line flat clip adaptive finger device in order to overcome the deficiencies of the prior art. The device can realize the straight-line flat clamping and adaptive composite grasping mode, which can not only linearly translate the second finger segment to grip the object, but also rotate the first finger segment to touch the object and then rotate the second finger segment to wrap and hold the object. object, to achieve the adaptive grip effect on objects of different shapes and sizes.

The technical scheme of the present invention is as follows:

A rack cosine telescopic straight-line flat clip adaptive finger device designed by the present invention includes a base, a first finger segment, a second finger segment, a proximal joint axis, a distal joint axis, a first axis, a second axis, a third axis A shaft, a spring member, a limit block, a first connecting rod, a second connecting rod, a third connecting rod, a fourth connecting rod, a driver and a transmission mechanism; the driver is fixedly connected to the base, and the output end of the driver is connected to the base. The input ends of the transmission mechanism are connected; the proximal joint shaft is sleeved in the base, the first finger segment is sleeved on the proximal joint shaft, the distal joint shaft is sleeved in the first finger segment, and the first finger segment is sleeved in the first finger segment. The two finger segments are sleeved on the distal joint shaft, the center line of the proximal joint shaft is parallel to the center line of the distal joint shaft; the output end of the transmission mechanism is connected with the first link; one end of the first link The other end of the first connecting rod is sleeved on the first shaft; one end of the second connecting rod is sleeved on the first shaft, and the other end of the second connecting rod is sleeved on the first shaft. three shafts; one end of the third connecting rod is sleeved on the second shaft, and the other end of the third connecting rod is sleeved on the third shaft; one end of the fourth connecting rod is sleeved on the proximal joint shaft , the other end of the fourth connecting rod is sleeved on the second shaft; the third shaft is sleeved in the second finger segment; the two ends of the spring element are respectively connected to the base and the fourth connecting rod; The position block is fixed on the base; in the initial state, the limit block is in contact with the fourth link; the center point of the proximal joint axis is A, the center point of the distal joint axis is B, and the center point of the third axis is C , the center point of the second axis is D, the length of line segment AB is equal to the length of line segment CD, the length of line segment BC is equal to the length of line segment AD; the center point of the first axis is F, and the length of line segment AF is greater than that of line segment BC It is characterized in that: the rack cosine telescopic straight-line flat clip adaptive finger device also includes a fourth shaft, an orthogonal chute, a first rack, a second rack, a first gear, a second gear, a middle a transmission mechanism, a first transmission shaft, a second transmission shaft and a surface cover of the second finger segment; the fourth shaft is sleeved on the third connecting rod, the orthogonal chute member is provided with a chute, the fourth The shaft is slidably embedded in the chute; the orthogonal chute piece is slidably embedded in the second finger segment, and the sliding direction of the orthogonal chute piece in the second finger segment is the same as that of the fourth shaft in the orthogonal chute piece The sliding direction is vertical; let the center point of the fourth axis be E, point C, point E and point D are collinear, the ratio of the length of the line segment CD to the length of the line segment CE is k, k>1; the The first rack is fixed on the orthogonal chute member; the first gear meshes with the first rack, the first transmission shaft is sleeved on the second finger segment; the second transmission shaft is sleeved on the on the second finger segment; the first gear is sleeved on the first transmission shaft; the second gear is sleeved on the second transmission shaft, the second gear meshes with the second rack, and the second rack is slidably inlaid on the second finger segment; the second finger segment surface cover is fixed on the second rack; the second finger segment surface cover is slidably embedded on the second finger segment; the input of the first gear and the intermediate transmission mechanism The output end of the intermediate transmission mechanism is connected with the second gear, and the intermediate transmission mechanism, the first gear and the second gear constitute a transmission relationship, and the first gear, the intermediate transmission mechanism and the second gear are in a transmission relationship. The transmission of two gears makes the ratio of the moving speed of the second rack relative to the second finger segment to the moving speed of the first rack relative to the second finger segment is k; the surface cover of the second finger segment, the first tooth The rod, the second rack and the orthogonal chute member are respectively parallel to each other with respect to the movement direction of the second finger segment.

The rack cosine telescopic linear flat clip adaptive finger device of the present invention is characterized in that the intermediate transmission mechanism adopts one or more combinations of gears, connecting rods, transmission belts, chains and ropes.

The rack cosine telescopic linear flat clip adaptive finger device of the present invention is characterized in that: the driver adopts a motor, a cylinder or a hydraulic cylinder.

The rack cosine telescopic linear flat clip adaptive finger device according to the present invention is characterized in that: the first spring member adopts a tension spring.

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

The device of the invention comprehensively realizes the functions of straight-line parallel gripping and self-adaptive grasping of the robot fingers by using a plurality of connecting rods, two finger segments, two joint shafts, a driver, a plurality of connecting rods, a transmission mechanism and a spring member; The crank-rocker mechanism is used to realize the grasping motion of the first finger segment and the second finger segment; the parallelogram mechanism and the spring are used to realize the translation of the second finger segment to maintain a fixed attitude; the sinusoidal mechanism and double The rack-driven linear speed-increasing mechanism realizes that the second finger surface cover moves in a straight line relative to the base; the first spring is used to cooperate to realize the automatic rotation of the second finger after the contact of the first finger is blocked by the object to touch objects. According to the different shapes and positions of the objects, the device can linearly translate the second finger segment, while the second finger segment maintains a fixed posture to hold the object, and can automatically rotate the second finger segment after the first finger segment touches the object. Contact the object to achieve the purpose of adaptively wrapping objects of different shapes and sizes; the grasping range is large, and the grasping is stable and reliable; two finger segments are driven by one driver; the device has simple structure, low processing, assembly and maintenance costs, and is suitable for Robotic hand.

Description of drawings

FIG. 1 is a three-dimensional appearance view of an embodiment of a rack cosine telescopic straight-line flat clip adaptive finger device designed by the present invention.

FIG. 2 is a front view of the embodiment shown in FIG. 1 .

FIG. 3 is a schematic diagram of the mechanism of the embodiment shown in FIG. 1 (some parts are not drawn), and the figure shows the positions of points A, B, C, D, E, F and straight line K.

Fig. 4 is a front view of the embodiment shown in Fig. 1 (sectioned parts).

FIG. 5 is a perspective cross-sectional view of the embodiment shown in FIG. 1 (sectioned base and first finger segment).

FIG. 6 is an exploded view of the embodiment shown in FIG. 1 .

7 is a schematic diagram of the flat clamp grasping an object in which the second finger segment contacts the object in the embodiment shown in FIG. 1 , and the two-dot chain lines represent three states in the movement process.

8 to 10 are action process diagrams of the linear adaptive grasping of the embodiment shown in FIG. 1 . During the grasping process, the distal joint axis moves linearly in parallel, while the second finger segment maintains the original posture.

11 and 13 are action process diagrams of the embodiment shown in FIG. 1 for adaptively grasping an object. During the grasping process, the first finger segment is blocked by the object and cannot move any more, and the second finger segment continues to circle the distal joint under the action of the motor. The axis rotates, so as to achieve the purpose of adaptively grasping the object.

14 to 16 are the fourth connecting rod 44 , the limiting block 8 and the spring member 9 (a cross-sectional view of the base) during the grabbing process of the embodiment shown in FIG. 1 .

In Figures 1 to 16:

1-base, 2-first segment, 3-second segment, 4-proximal joint axis,

5-Distal joint shaft, 6-Second finger surface cover, 7-Orthogonal chute piece, 8-Limiting block,

9-spring member, 21-first shaft, 22-second shaft, 23-third shaft,

24-the fourth shaft, 31-first gear, 32-second gear, 33-intermediate transmission mechanism,

34-first transmission shaft, 34-second transmission shaft, 41-first connecting rod, 42-second connecting rod,

43-third link, 44-fourth link, 51-first rack, 52-second rack,

200-Driver, 201-Transmission mechanism, 300-Object.

Detailed ways

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

A rack cosine telescopic straight-line flat clip adaptive finger device designed by the present invention includes a base 1, a first finger segment 2, a second finger segment 3, a proximal joint shaft 4, a distal joint shaft 5, a first shaft 21, The second shaft 22, the third shaft 23, the spring member 9, the limit block 8, the first link 41, the second link 42, the third link 43, the fourth link 44, the driver 200 and the transmission mechanism 201; The driver 200 is fixedly connected to the base 1, and the output end of the driver 200 is connected to the input end of the transmission mechanism 201; the proximal joint shaft 4 is sleeved in the base 1, and the first finger segment 2 is sleeved On the proximal joint shaft 4, the distal joint shaft 5 is sleeved on the first finger segment 2, the second finger segment 3 is sleeved on the distal joint shaft 5, and the center line of the proximal joint shaft 4 is connected to the distal joint shaft 4. The center line of the joint shaft 5 is parallel; the output end of the transmission mechanism 201 is connected to the first connecting rod 41; one end of the first connecting rod 41 is sleeved on the proximal joint shaft 4, and the other end of the first connecting rod 41 sleeved on the first shaft 21; one end of the second connecting rod 42 is sleeved on the first shaft 21, and the other end of the second connecting rod 42 is sleeved on the third shaft 23; the third connecting rod One end of 43 is sleeved on the second shaft 22, the other end of the third connecting rod 43 is sleeved on the third shaft 23; one end of the fourth connecting rod 44 is sleeved on the proximal joint shaft 4, and the fourth connecting rod The other end of the rod 44 is sleeved on the second shaft 22; the third shaft 23 is sleeved in the second finger segment 3; the two ends of the spring member 9 are respectively connected to the base 1 and the fourth connecting rod 44; The limit block 8 is fixed on the base 1; in the initial state, the limit block 8 is in contact with the fourth connecting rod 44; the center point of the proximal joint shaft 4 is set as A, and the center point of the distal joint shaft 5 is set as B , the center point of the third axis 23 is C, the center point of the second axis 22 is D, the length of the line segment AB is equal to the length of the line segment CD, and the length of the line segment BC is equal to the length of the line segment AD; The center point is F, and the length of the line segment AF is greater than the length of the line segment BC; it is characterized in that: the rack cosine telescopic straight-line flat clip adaptive finger device also includes a fourth shaft 24, an orthogonal chute member 7, and a first rack 51. , the second rack 52, the first gear 31, the second gear 32, the intermediate transmission mechanism 33, the first transmission shaft 34, the second transmission shaft 35 and the second finger surface cover; the fourth shaft 24 is sleeved on the On the third connecting rod 43, the orthogonal chute member 7 is provided with a chute, and the fourth shaft 24 is slidably embedded in the chute; the orthogonal chute member 7 is slidably embedded in the second finger segment 3, The sliding direction of the orthogonal chute member 7 in the second finger segment 3 is perpendicular to the sliding direction of the fourth shaft 24 in the orthogonal chute member 7; let the center point of the fourth shaft 24 be E, the point C, point E and point D are collinear, the ratio of the length of the line segment CD to the length of the line segment CE is k, k>1; the first rack 51 is fixed on the orthogonal chute member 7; the The first gear 31 meshes with the first rack 51, the first transmission shaft 34 is sleeved on the second finger segment 3; the second transmission shaft 35 is sleeved on the second finger segment 3; the first gear 31 Sleeve on the first transmission shaft 34; the second gear 32 sleeves Connected to the second transmission shaft 35, the second gear 32 meshes with the second rack 52, the second rack 52 is slidably embedded on the second finger segment 3; the surface cover of the second finger segment is fixed on the second tooth The second finger segment surface cover is slidably embedded on the second finger segment 3; the first gear 31 is connected to the input end of the intermediate transmission mechanism 33, and the output end of the intermediate transmission mechanism 33 is connected to the second finger segment 3. The gears 32 are connected, and the intermediate transmission mechanism 33, the first gear 31 and the second gear 32 constitute a transmission relationship. After the transmission of the first gear 31, the intermediate transmission mechanism 33 and the second gear 32, the second rack 52 is relatively The ratio of the moving speed of the second finger segment 3 to the moving speed of the first rack 51 relative to the second finger segment 3 is k; the second finger segment surface cover, the first rack 51 , the second rack 52 and the The four orthogonal chute members 7 are parallel to each other with respect to the movement direction of the second finger segment 3 .

The rack cosine telescopic linear flat clip adaptive finger device according to the present invention is characterized in that: the intermediate transmission mechanism 33 adopts one or more combinations of gears, connecting rods, transmission belts, chains and ropes.

In this embodiment, the driver 200 adopts a motor, and the spring member 9 adopts a tension spring.

The working principle of this embodiment is described as follows in conjunction with the accompanying drawings:

When the present embodiment is in the initial state, the fourth link 44 abuts against the limit block 8 and remains relatively stationary with the base 1 under the pulling force of the spring member 9 . The action of the parallelogram mechanism formed by the connecting rod 43 and the fourth connecting rod 44 and the setting of the position of the limit block 8 make the second finger segment 3 remain parallel to the vertical direction. The motor 200 rotates, and drives the first connecting rod 41 to rotate counterclockwise through the transmission mechanism 201 (reducer and pulley, etc.) The triaxial 23 exerts a thrust. The thrust has a leftward component in the horizontal direction. Due to the action of the parallelogram mechanism formed by the first finger segment 2, the second finger segment 3, the third link 43 and the fourth link 44, the second finger segment is 3. Make a circular arc movement to the left, and at the same time, the first finger segment 2 rotates counterclockwise around the proximal joint axis 4. The robot finger has two grasping modes, namely, the linear flat-clamp grasping mode and the adaptive envelope grasping mode.

(1) Linear Flat Clamp Grab Mode

In the process that the motor drives the robot's fingers to move through the transmission mechanism 201, when the first finger segment 2 does not contact the object 300, it enters the linear flat gripping mode: the second finger segment 3 maintains a fixed posture relative to the base 1 and moves in parallel. The second finger surface cover 6 can be driven by a special mechanism to move in the vertical direction relative to the second finger segment 3 so that the second finger surface cover 6 can move in a straight line relative to the base 1 and at the same time in the horizontal direction. The second finger segment 3 moves synchronously. The grasping process ends when the second finger segment surface cover 6 contacts the object 300 and exerts a sufficient grasping force. This mode makes it unnecessary to coordinate a movement of the end of the robot arm for a certain displacement when the sheet object 300 on the worktable is clamped, which simplifies the sensor control system. Combining the geometric relationship of the mechanism of the robot finger (as shown in FIG. 3 ), the linear motion process of the surface cover 6 of the second finger segment in the linear flat clamping mode is proved below.

Given that s ₂ =k·s ₁ , L=kd,

Let θ be the rotation angle of the third link 43 relative to the vertical direction, unit: rad; the lengths of line segments AB and CD are L, unit: mm; the length of line segment CE is d, unit: mm; The sliding distance in the second finger segment 3 is s ₁ , unit: mm; the sliding distance of the second rack 52 in the second finger segment 3 is s ₂ , unit: mm; point E is relative to the second finger segment 3 at The displacement in the vertical direction is t, and the distance that the point C falls in the vertical direction relative to the base 1 during the rotation is q, unit: mm.

Then there are:

Joint solution:

s ₂ =L·(1-cosθ)=q.

That is, the distance s ₂ that the second rack 52 rises relative to the point C in the vertical direction is equal to the distance q that the point C descends relative to the base 1 in the vertical direction, that is, the second rack 52 is relative to the base 1. The displacement in the vertical direction is 0, and because the second finger surface cover 6 is fixed to the second rack 52, the second finger surface cover 6 has no displacement relative to the base 1 in the vertical direction, that is, The second finger surface cover 6 moves in a straight line relative to the base 1 .

In the above process, when the second finger segment surface cover 6 touches the object 300, the grasping ends. The grasping process is shown in Figure 7, wherein the double-dotted line represents the grasping state of the other three flat clips. Take the straight-line-parallel gripping mode.

(2) Adaptive grab mode

During the above process, if the second finger segment surface cover 6 does not contact the object 300, but the first finger segment 2 contacts the object 300 and is blocked, the first finger segment 2 cannot be rotated further. At this time, the first link 41, The second connecting rod 42 , the second finger segment 3 and the first finger segment 2 constitute a crank-rocker mechanism. The motor continues to rotate, and the first connecting rod 41 is driven by the transmission mechanism 201 to continue to rotate counterclockwise, and the second finger segment 3 is driven to rotate counterclockwise around the distal joint shaft 5 . Due to the action of the parallelogram mechanism formed by the first finger segment 2, the second finger segment 3, the third link 43 and the fourth link 44, the torque of the second finger segment 3 is transmitted to the fourth link 44 so that the fourth link The connecting rod 44 rotates counterclockwise around the proximal joint shaft 4 against the action of the spring member 9 , thereby driving the second finger segment 3 to rotate counterclockwise around the distal joint shaft 5 . Until the second finger segment 3 touches the object 300, the grasping ends. This kind of grasping can adapt to objects 300 of different shapes and sizes—that is, an adaptive grasping effect is achieved. This process is shown in FIGS. 8 to 13 , in which FIGS. 8 to 11 show that the distal joint axis 5 is straight to the right Approaching the object 300, while the second finger segment 3 is coupled and rotated, FIG. 12 and FIG. 13 show the process that the first finger segment 2 has contacted the object 300 and is blocked from moving, and the second finger segment 3 continues to rotate adaptively around the distal joint axis 5.

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

The device of the invention comprehensively realizes the functions of straight-line parallel gripping and self-adaptive grasping of the robot fingers by using a plurality of connecting rods, two finger segments, two joint shafts, a driver, a plurality of connecting rods, a transmission mechanism and a spring member; The crank-rocker mechanism is used to realize the grasping motion of the first finger segment and the second finger segment; the parallelogram mechanism and the spring are used to realize the translation of the second finger segment to maintain a fixed attitude; the sinusoidal mechanism and double The rack-driven linear speed-increasing mechanism realizes that the second finger surface cover moves in a straight line relative to the base; the first spring is used to cooperate to realize the automatic rotation of the second finger after the contact of the first finger is blocked by the object to touch objects. According to the different shapes and positions of the objects, the device can linearly translate the second finger segment, while the second finger segment maintains a fixed posture to hold the object, and can automatically rotate the second finger segment after the first finger segment touches the object. Contact the object to achieve the purpose of adaptively wrapping objects of different shapes and sizes; the grasping range is large, and the grasping is stable and reliable; two finger segments are driven by one driver; the device has simple structure, low processing, assembly and maintenance costs, and is suitable for Robotic hand.

Claims (4)

1. A rack cosine telescopic straight-line flat clip adaptive finger device, comprising a base, a first finger segment, a second finger segment, a proximal joint axis, a distal joint axis, a first axis, a second axis, a third axis, Spring member, limit block, first connecting rod, second connecting rod, third connecting rod, fourth connecting rod, driver and transmission mechanism; the driver is fixedly connected with the base, and the output end of the driver is connected with the transmission mechanism The input end of the joint is connected; the proximal joint shaft is sleeved in the base, the first finger segment is sleeved on the proximal joint shaft, the distal joint shaft is sleeved in the first finger segment, and the second finger is sleeved on the proximal joint shaft. The segment is sleeved on the distal joint shaft, and the center line of the proximal joint shaft is parallel to the center line of the distal joint shaft; the output end of the transmission mechanism is connected with the first connecting rod; one end of the first connecting rod is sleeved On the proximal joint shaft, the other end of the first connecting rod is sleeved on the first shaft; one end of the second connecting rod is sleeved on the first shaft, and the other end of the second connecting rod is sleeved on the third shaft one end of the third connecting rod is sleeved on the second shaft, and the other end of the third connecting rod is sleeved on the third shaft; one end of the fourth connecting rod is sleeved on the proximal joint shaft, and the first The other end of the four connecting rod is sleeved on the second shaft; the third shaft is sleeved in the second finger segment; the two ends of the spring element are respectively connected to the base and the fourth connecting rod; the limiting block It is fixed on the base; the limit block is in contact with the fourth link in the initial state; the center point of the proximal joint axis is A, the center point of the far joint axis is B, the center point of the third axis is C, and the center point of the third axis is C. The center point of the two axes is D, the length of the line segment AB is equal to the length of the line segment CD, and the length of the line segment BC is equal to the length of the line segment AD; the center point of the first axis is F, and the length of the line segment AF is greater than the length of the line segment BC. It is characterized in that: the rack cosine telescopic straight-line flat clip adaptive finger device also includes a fourth shaft, an orthogonal chute, a first rack, a second rack, a first gear, a second gear, and an intermediate transmission mechanism , the first transmission shaft, the second transmission shaft and the surface cover of the second finger segment; the fourth shaft is sleeved on the third connecting rod, the orthogonal chute member is provided with a chute, and the fourth shaft slides It is embedded in the chute; the orthogonal chute piece is slidably embedded in the second finger segment, and the sliding direction of the orthogonal chute piece in the second finger segment is the same as the sliding direction of the fourth axis in the orthogonal chute piece The direction is vertical; let the center point of the fourth axis be E, point C, point E and point D are collinear, the ratio of the length of the line segment CD to the length of the line segment CE is k, k>1; the first The rack is fixed on the orthogonal chute member; the first gear meshes with the first rack, the first transmission shaft is sleeved on the second finger segment; the second transmission shaft is sleeved on the second on the finger segment; the first gear is sleeved on the first transmission shaft; the second gear is sleeved on the second transmission shaft, the second gear is engaged with the second rack, and the second rack is slidably embedded in the first transmission shaft. on the second finger segment; the second finger segment surface cover is fixed on the second rack; the second finger segment surface cover is slidably embedded on the second finger segment; the first gear is connected to the input end of the intermediate transmission mechanism , the output end of the intermediate transmission mechanism is connected with the second gear, and the intermediate transmission mechanism, the first gear and the second gear constitute a transmission relationship, through the first gear, the intermediate transmission mechanism and the second gear. drive, so that the ratio of the moving speed of the second rack relative to the second finger segment to the moving speed of the first rack relative to the second finger segment is k; the surface cover of the second finger segment, the first rack, the The two racks and the orthogonal chute members are parallel to each other with respect to the moving directions of the second finger segments. 2. The rack cosine telescopic straight-line flat clip adaptive finger device according to claim 1, wherein the intermediate transmission mechanism adopts one or more combinations of gears, connecting rods, transmission belts, chains, and ropes . 3 . The rack-cosine telescopic straight-line flat clip adaptive finger device according to claim 1 , wherein the driver adopts a motor, an air cylinder or a hydraulic cylinder. 4 . 4 . The rack cosine telescopic straight-line flat clip adaptive finger device according to claim 1 , wherein the spring member is a tension spring. 5 .

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