CN107243915B - Parallel-clamping coupling switching self-adaptive robot finger device with duplex racks - Google Patents

Abstract

A parallel-clamping coupling switching self-adaptive robot finger device for a duplex rack belongs to the technical field of robot hands and comprises a base, two finger sections, two joint shafts, a motor, a half gear, a connecting piece, a rotating shaft, a lower rack, an upper rack, a middle shaft, two limiting blocks, a sleeve, a spring piece and the like. The device realizes the robot finger flat clamp grabbing, coupling grabbing and self-adaptive grabbing multiple grabbing modes. The device realizes stable switching of the flat clamp and the coupling by utilizing the half gear, the transmission precision of the flat clamp and the coupling stage is improved by arranging the half gear, the mechanism is simplified by utilizing the self-adaptive function of the gear-rack mechanism, and the contradiction between the flat clamp or the coupling state and the self-adaptive state is avoided by utilizing the cooperation of the spring piece and the limiting slide block; the grabbing range is large; the two joints are driven by a single motor, so that a complex sensing and control system is not needed; simple structure, small volume and low cost.

Description

A dual rack and flat clip coupling switching adaptive robot finger device

technical field

The invention belongs to the technical field of robotic hands, and in particular relates to a structural design of a double rack flat clip coupling switching adaptive robot finger device.

Background technique

The underactuated robotic hand refers to a type of robotic hand with more joint degrees of freedom than the number of motors used. The adaptive grasping function of this type of robotic hand can grasp a variety of objects of different sizes and shapes. Accurate and stable gripping is achieved without complex sensing and control modules. The underactuated robot hand has a simple mechanical structure, low cost, and powerful functions, and can adapt to the grasping needs of robot hands in different fields such as industrial robots, social service robots, or human prosthetics.

The two basic grasping categories for underactuated robotic hands with two joint degrees of freedom are coupled grasping modes and adaptive grasping modes. The coupled grasping mode means that the two joints of the robot hand move according to a certain proportional relationship. The coupled capture mode is divided into forward coupling and reverse coupling. Forward coupling is usually also called coupled grasping. The bending motion effect of coupled grasping is anthropomorphic, and can realize the hooking of thin rod-shaped objects; reverse coupling is called flat clamp grasping when the movement ratio is 1:1. , can achieve parallel clamping of objects with two parallel surfaces. Adaptive grasping means that the final motion posture of the robot hand is affected by the shape and size of the grasped object, and the envelope of the object can be realized.

Through the combination of basic grasping modes, two composite grasping modes are formed: coupling adaptive grasping mode and flat clip adaptive grasping mode. These two composite grasping modes are divided into two stages in the grasping process. In the first stage, the robot hand moves in the mode of coupling grasping and flat clamping grasping respectively, which can grasp objects, and can also be used as a The two-stage preparatory movement; the second stage for the robot hand to perform adaptive grasping.

An existing dual-joint parallel underactuated robot finger device (Chinese patent CN101633171B) includes a base, a motor, two joint shafts, two finger segments, a coupling transmission mechanism, an underactuated transmission mechanism and multiple springs. The device realizes the coupling adaptive grasping mode. When the finger touches the object, it presents the effect of multi-joint coupling rotation, which is very anthropomorphic, and also helps to grasp the object by pinching; when the finger touches the object, it adopts a The effect of multi-joint under-actuated rotation has the advantage of automatically adapting to the size of the grasped object. Its shortcoming is that the device can only realize the coupling adaptive grasping mode, and cannot realize the flat clip adaptive grasping mode; in addition, the mechanism is complicated, and installation and maintenance are difficult; there are too many springs, and the springs are used to decouple and adjust the coupling. The contradiction between the transmission mechanism and the self-adaptive transmission mechanism often causes large deformation of multiple spring elements, resulting in excessive and unnecessary energy loss.

There is an adaptive robot finger device for coupling and switching of flat clips of flexible parts (Chinese patent CN105835083A), which can realize manual switching of flat clip adaptive grabbing mode and coupling adaptive grabbing mode, and adopts half gears, connecting parts, and limit protrusions. block, two sets of flexible member transmission mechanisms and two spring members. Its disadvantage is that during the forward rotation of the first finger section around the centerline of the proximal joint axis, only the lower part of the tendon cord is on the outer edge of the semi-gear arc, while a considerable part of the tendon cord is connected by the shortest broken line. The transition wheel between the upper part of the half gear and the middle part of the first finger section causes the transmission to be unstable during the gripping stage of the flat clamp, and there is a large error in the transmission (that is, there is a control dead zone). During the rotation of the first finger section, the second finger section The segment does not move for a period of time, so that the translation of the second finger segment cannot be accurately guaranteed, so it is not an accurate parallel clamping; in addition, the number of components is large, the structure is complex, the volume is large, and the cost is high.

Contents of the invention

The purpose of the present invention is to overcome the disadvantages of the prior art, and provide a double rack flat clip coupling switching self-adaptive robot finger device. The device can realize the flat clamp adaptive grasping mode, and after a simple manual switch, it can also realize the coupling adaptive grasping mode; To bend and decouple to pinch objects, you can also rotate the first finger segment and the second finger segment to adaptively envelope objects of different shapes and sizes; the grabbing range is large; Simple and low cost; no complicated sensing and control system required.

Technical scheme of the present invention is as follows:

The present invention designs a dual rack flat clip coupling switching adaptive robot finger device, including a base, a first finger segment, a second finger segment, a proximal joint axis, a distal joint axis, a motor, a transmission mechanism, a first Pulley, second pulley and transmission belt; the proximal joint shaft is movably sleeved in the base, the first finger segment is sleeved on the proximal joint shaft, and the distal joint shaft is movably sleeved on the first finger segment Among them, the second finger section is sleeved on the distal joint shaft; the centerline of the proximal joint shaft is parallel to the centerline of the distal joint shaft; the motor is fixedly connected to the base, and the transmission mechanism is arranged on the base Among them, the output shaft of the motor is connected to the input end of the transmission mechanism, and the output end of the transmission mechanism is connected to the first pulley; the first pulley is movably sleeved on the proximal joint shaft, and the second belt The wheel sleeve is fixed on the distal joint shaft; the second pulley is fixedly connected with the second finger segment; the transmission belt connects the first pulley and the second pulley; the transmission belt, the first pulley and the second pulley The three cooperate to form a pulley transmission relationship; the pulley transmission part forms an "O" shape; the transmission radius of the first pulley is greater than the transmission radius of the second pulley; it is characterized in that: the double rack The flat clip coupling switching adaptive robot finger device also includes a half gear, a gear, a connecting piece, a rotating shaft, a lower rack, an upper rack, an intermediate shaft, a first limit block, a second limit block, a sleeve and a spring; The connecting piece is sleeved on the proximal joint shaft, and the rotating shaft is sleeved in the connecting piece; the centerline of the rotating shaft is perpendicular to the centerline of the proximal joint shaft; the half gear is sleeved on the rotating shaft; the half The gear is concentric with the proximal joint shaft; the gear sleeve is fixed on the distal joint shaft; the lower rack is engaged with the half gear; the upper end of the lower rack is fixedly connected to the sleeve; the intermediate shaft is sleeved on the sleeve middle; the lower end of the upper rack is fixedly connected to the intermediate shaft; the upper rack is meshed with the gear; the upper rack is slidably embedded in the first finger segment; the two ends of the spring are respectively connected to the half gear and base; the transmission radius of the semi-gear is equal to the transmission radius of the gear; the centerline of the proximal joint shaft and the centerline of the far joint shaft form a plane U, and the rotating shaft is located on the plane U; the intermediate shaft and The rotating shafts are in the same plane; the first limit block and the second limit block are respectively fixed to the base; in the initial state, when the half gear is on one side, the half gear is in contact with the first limit block, and when the half gear is on the other side When on one side, the half gear is in contact with the second limit block.

The double rack flat clip coupling switching self-adaptive robot finger device according to the present invention is characterized in that: the spring member adopts a tension spring, a compression spring, a leaf spring or a torsion spring.

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

The device of the present invention utilizes a base, two finger sections, two joint shafts, a motor, a half gear, a gear, a connector, a rotating shaft, a lower rack, an upper rack, an intermediate shaft, two limit blocks, a sleeve and a spring pieces etc. The device realizes multiple grasping modes of robot finger flat clamp grasping, coupled grasping and adaptive grasping. The device uses the half gear to realize the smooth switching between the flat clip and the coupling, and the setting of the half gear improves the transmission accuracy of the flat clip and the coupling stage, and the self-adaptive function of the rack and pinion mechanism is used to simplify the mechanism. The cooperation of the slider avoids the contradiction between the flat clip or the coupling state and the self-adaptive state; the grasping range is large; the under-actuation method is adopted, and the two joints are driven by a single motor without complex sensing and control systems; the structure is simple and the volume is small ,low cost. The device has simple structure, small size, low manufacturing and maintenance costs, and is suitable for robot hands.

Description of drawings

Fig. 1 is the front appearance view of an embodiment of the double rack flat clip coupling switching adaptive robot finger device designed by the present invention.

Fig. 2 and Fig. 3 are side appearance views of the embodiment shown in Fig. 1 .

Fig. 4 is a three-dimensional exploded view of this embodiment (some parts are not drawn).

FIG. 5 to FIG. 8 are schematic diagrams of the action process of the embodiment shown in FIG. 1 in the adaptive envelope grabbing object in the flat clip adaptive mode.

FIG. 9 to FIG. 11 are schematic diagrams of the action process of the embodiment shown in FIG. 1 in translationally moving the second finger segment to clamp the object in the flat clamp adaptive mode.

FIG. 12 to FIG. 14 are schematic diagrams of the action process of the embodiment shown in FIG. 1 in the adaptive envelope grabbing object in the coupling adaptive mode.

FIG. 15 to FIG. 16 are schematic diagrams of the action process of coupling and grasping objects in the embodiment shown in FIG. 1 in the coupling adaptive mode.

In Figures 1 to 16:

1-base, 14-motor 2-first finger section, 3-second finger section, 4-proximal joint shaft, 41-rotating shaft, 5-distal joint shaft, 61-first pulley, 62-second belt Wheel, 71-half gear, 72-gear, 81-lower rack, 82-upper rack, 821-intermediate shaft, 9-spring.

Detailed ways

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

An embodiment of the dual rack flat clip coupling switching self-adaptive robot 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 motor, a transmission mechanism, and a second finger segment. A pulley, a second pulley and a transmission belt; the proximal joint shaft is movably sleeved in the base, the first finger segment is sleeved on the proximal joint shaft, and the distal joint shaft is movably sleeved on the first finger In the section, the second finger segment is sleeved on the distal joint shaft; the centerline of the proximal joint shaft is parallel to the centerline of the distal joint shaft; the motor is fixedly connected to the base, and the transmission mechanism is arranged on the base In the seat, the output shaft of the motor is connected with the input end of the transmission mechanism, and the output end of the transmission mechanism is connected with the first pulley; the first pulley is movably sleeved on the proximal joint shaft, and the second The pulley sleeve is fixed on the distal joint shaft; the second pulley is fixedly connected with the second finger segment; the transmission belt connects the first pulley and the second pulley; the transmission belt, the first pulley and the second belt Cooperate between the three pulleys to form a pulley transmission relationship; the pulley transmission part forms an "O" shape; the transmission radius of the first pulley is greater than the transmission radius of the second pulley; this embodiment also includes half gears, Gears, connectors, shafts, lower racks, upper racks, intermediate shafts, first limit blocks, second limit blocks, sleeves and springs; the connectors are sleeved on the proximal joint shaft, and the The rotating shaft is sleeved in the connector; the center line of the rotating shaft is perpendicular to the center line of the proximal joint shaft; the half gear is sleeved on the rotating shaft; the half gear is concentric with the proximal joint shaft; On the joint shaft; the lower rack meshes with the half gear; the upper end of the lower rack is fixedly connected to the sleeve; the intermediate shaft is sleeved in the sleeve; the lower end of the upper rack is fixedly connected to the intermediate shaft ; The upper rack is meshed with the gear; the upper rack is slidably embedded in the first finger section; the two ends of the spring are respectively connected to the half gear and the base; the transmission radius of the half gear and the transmission of the gear The radii are equal; the centerline of the proximal joint axis and the centerline of the distal joint axis form a plane U, and the rotating shaft is located on the plane U; the intermediate shaft and the rotating shaft are in the same plane; the first limiting block, the second limiting The blocks are respectively affixed to the base; in the initial state, when the half gear is on one side, the half gear is in contact with the first limit block, and when the half gear is on the other side, the half gear is in contact with the second limit block.

The double rack flat clip coupling switching self-adaptive robot finger device according to the present invention is characterized in that: the spring member adopts a tension spring, a compression spring, a leaf spring or a torsion spring.

This embodiment also adopts parts such as some bearings, some sleeves, some screws and some pins, which belong to known and commonly used technologies and will not be described in detail.

The working principle of the present embodiment, in conjunction with accompanying drawing, is described as follows:

The device has two grabbing modes: one is the coupling adaptive grabbing mode, and the other is the flat clip adaptive grabbing mode. The switching between the two modes can be done by the half gear around the rotating shaft and the lower rack around the intermediate shaft. Rotate to achieve.

The manual switching method between flat clip adaptive grabbing mode and coupling adaptive grabbing mode is:

Rotate the half gear 180 degrees around the shaft, and rotate the lower rack meshed with the half gear 180 degrees around the intermediate shaft.

1) Realization of self-adaptive grasping mode of flat clamp

The half gear is moved to the side towards the rear, and at this moment, the lower rack, the half gear, the upper rack, the sleeve, the intermediate shaft and the gear form the same direction constant speed transmission. The following is a detailed description of the flat clip adaptive grabbing mode:

The initial position is the finger straight state.

When the motor 14 starts to rotate forward, the transmission mechanism drives the first pulley 61 to rotate, and the transmission belt wants to make the second pulley 62 rotate, and because the second pulley, the second finger segment and the gear are fixedly connected, they are held by the gear. Influenced by the posture, the first finger segment 2 rotates forward around the proximal joint axis 4, and the second finger segment maintains the initial state posture.

When the rotation angle of the half gear 71 around the proximal joint axis is 0 degrees, the position of the half gear relative to the base 1 remains unchanged; since the transmission radius of the half gear 71 and the gear 72 are equal (that is, the two rotation angles are the same, the transmission ratio is 1) , under the action of the lower rack, sleeve, intermediate shaft and upper rack, no matter where the first finger segment 2 is, the gear 72 always maintains the same angle with the half gear 71, and the gear 72 only performs translational movement relative to the base 1 and not rotate, because the gear 72 is fixedly connected to the second finger segment 3, so the second finger segment 3 only performs a translational movement relative to the base 1 and does not rotate; when the rotation angle of the half gear around the joint axis is positive, The rotation angle of the gear 72 is equal to the rotation angle of the half gear 71 .

When the present embodiment grabs the object 17 , the driver 14 is driven by the transmission mechanism so that the first pulley 61 rotates forward, and the rotation angle of the first pulley 61 relative to the base 1 is α. Under the action of the transmission belt, the rotation angle of the first pulley 6 relative to the first finger segment 2 is proportional to the rotation angle of the second pulley 62 relative to the first finger segment 2 . Assume that the transmission ratio from the first pulley 61 to the second pulley 62 by the transmission belt is i, and this transmission ratio is the rotating speed of the first pulley 61 (relative to the first finger section 2) and the rotating speed of the second pulley 62 (relative to the ratio of the first finger section 2), it is equal to the ratio of the transmission radius of the second pulley 62 to the transmission radius of the first pulley 61. Since the transmission radius of the first pulley 61 is greater than that of the second pulley 62, it is a speed-up transmission, and the output speed is greater than the input speed, so the transmission ratio i is less than 1. Let the rotation angle of the first finger segment 2 around the proximal joint axis 4 be δ. Since the second pulley 62 is fixedly connected to the second finger segment 3, and the second finger segment 3 does not rotate relative to the base 1, the second pulley 62 does not rotate relative to the base 1 at this time, so It can be deduced that the device of this embodiment will be balanced at a position satisfying the following (formula 1):

α＝δ(1-i) (Formula 1)

Since i is less than 1, a different angle where α and δ are respectively positive can be obtained (where α is smaller than δ). Therefore, when the driver 14 is driven by the transmission mechanism, the first pulley 61 rotates through an angle α. At this time, the first finger segment 2 rotates through an angle δ around the proximal joint axis 4, and the second finger segment 3 rotates relative to the base. 1 is always the same posture, but the position has changed. This is the stage of parallel clamping (as shown in Figure 4, Figure 5, Figure 6, Figure 12). This stage is suitable for holding the object 17 by the second finger segment 3 , or by stretching out the second finger segment 3 to open the object 17 from inside to outside. For example, in the taking of a hollow cylinder, the inner side of the object is spread out to support the wall of the cylinder, thereby taking the object.

When the first finger segment 2 touches the object 17 and is blocked by the object 17 and can no longer rotate, it will enter the second stage of the adaptive envelope (as shown in Figure 4, Figure 5, Figure 10, Figure 11, Figure 13), at this time The driver 14 drives the first pulley 6 through the transmission of the transmission mechanism, so that the second finger section 3, the second pulley 62 and the gear 72 fixedly connected together rotate around the distal joint shaft 5 at the same time, and the half gear is driven by the lower rack 81 71 rotates around the proximal joint axis 4, and the spring member 9 is deformed. At this time, the second finger segment 3 will continue to rotate around the center line of the distal joint axis 5 until the second finger segment 3 touches the object 17, and the adaptive envelope capture is completed. object effect. For objects of different shapes and sizes, this embodiment is self-adaptive and can universally grasp various objects.

The process of releasing the object 17: the driver 14 is reversed, and the subsequent process is just opposite to the above-mentioned process of grabbing the object 17, which will not be described in detail.

2) Realization of coupling adaptive grabbing mode

The half gear 71 is toggled to the side (front) towards the grasping object 17, and the lower rack 81, the half gear 71 and the gear 72 constitute a reverse constant speed transmission.

The following is an introduction to the coupled adaptive grabbing mode.

When the driver 14 drives the first finger section 2 to rotate forwardly and lean against the object 17 through the first pulley 61, the transmission belt and the second pulley 62, the half gear 9 is always leaning against the limit projection and does not rotate. The rotation of the first finger section 2 relative to the half gear 71 will cause the lower rack 81 to partly leave the half gear 71. At this time, the spring member 9 will pull the first finger section 3 to the side of the grasping object 17, thereby tightening the lower rack. 81 , the second finger section 3 turns toward the object 17 . At this point there will be:

α＝δ(1+i) (Formula 2)

The process of releasing the object 17 is opposite to the process described above, and will not be described in detail.

The device of the present invention utilizes the driver, belt transmission mechanism, rack and pinion transmission mechanism, spring parts, half gears, rotating shafts, half gear connectors, half gear bumps and limit bumps to comprehensively realize the self-adaptive grasping of robot finger flat clips Mode and coupling adaptive grasping mode can be easily switched: the device can realize flat clip adaptive grasping mode, and after simple manual switching, it can realize coupling adaptive grasping mode. In the flat clip adaptive grasping mode, the device can not only move the second finger segment to pinch the object, but also rotate the first finger segment and the second finger segment to envelop objects of different shapes and sizes; in the coupling adaptive In the grasping mode, the device can simultaneously rotate the two joints, and naturally turn to the adaptive grasping stage of bending the second finger segment after the first finger segment is blocked from contacting the object; the grasping range is large; the underactuated The method uses one driver to drive two joints without complex sensing and control systems; the device has a compact structure, small size, low manufacturing and maintenance costs, and is suitable for robotic hands.

Claims (1)

1. A dual rack flat clip coupling switching adaptive robot finger device, including a base, a first finger section, a second finger section, a proximal joint shaft, a far joint shaft, a motor, a transmission mechanism, a first pulley, The second pulley and the transmission belt; the proximal joint shaft is movably sleeved in the base, the first finger segment is sleeved on the proximal joint shaft, and the distal joint shaft is movably sleeved in the first finger segment. The second finger segment is 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 motor is fixedly connected to the base, and the transmission mechanism is arranged in the base, so that The output shaft of the motor is connected with the input end of the transmission mechanism, and the output end of the transmission mechanism is connected with the first pulley; On the far joint shaft; the second pulley is affixed to the second finger segment; one side of the defined grasping object is the front of the double rack flat clip coupling switching adaptive robot finger device, and the other side is opposite That is, the side away from the grasping object is the rear of the device; the transmission belt connects the first pulley and the second pulley; the transmission belt, the first pulley and the second pulley cooperate to form a pulley Transmission relationship; the pulley transmission part forms an "O" shape; the transmission radius of the first pulley is greater than the transmission radius of the second pulley; it is characterized in that: the double rack flat clip coupling switching adaptive robot finger The device also includes a half gear, a gear, a connecting piece, a rotating shaft, a lower rack, an upper rack, an intermediate shaft, a first limiting block, a second limiting block, a sleeve and a spring; On the joint shaft, the rotating shaft is sleeved in the connector; the centerline of the rotating shaft is perpendicular to the centerline of the near-joint shaft; the half-gear is sleeved on the rotating shaft; the half-gear is concentric with the near-joint shaft; The gear sleeve is fixed on the distal joint shaft; the lower rack meshes with the half gear; the upper end of the lower rack is fixedly connected to the sleeve; the intermediate shaft is sleeved in the sleeve; The lower end is fixedly connected to the intermediate shaft; the upper rack is meshed with the gear; the upper rack is slidably embedded in the first finger segment; the two ends of the spring are respectively connected to the half gear and the base; The transmission radius is equal to the transmission radius of the gear; the centerline of the near-joint shaft and the centerline of the far-joint shaft form a plane U, and the rotating shaft is located on the plane U; the intermediate shaft is coplanar with the rotating shaft; the first limit block and the second limit block are fixedly connected to the base respectively; in the initial state, when the half gear is on one side, the half gear is in contact with the first limit block; when the half gear is on the other side, the half gear is in contact with the first limit block. The two limit blocks are in contact; the spring parts are tension springs, compression springs, leaf springs or torsion springs; The dual rack flat clamp coupling switching adaptive robot finger device has two grasping modes: one is a coupling adaptive grasping mode, and the other is a flat clamp adaptive grasping mode, and the two grasping modes Switching is realized by the rotation of the half gear around the axis of rotation and the rotation of the lower rack around the intermediate shaft.

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