A fast-response flexible three-fingered hand based on a bistable mechanism

Abstract

The present invention discloses a fast-response flexible three-finger hand based on a bistable mechanism, which relates to the field of robot end effectors and includes a grasping mechanism capable of adaptively grasping objects of various shapes; a bistable mechanism for stably maintaining the grasping and opening states of the flexible three-finger hand; a force adjustment mechanism for adjusting the trigger sensitivity and grasping force of the flexible three-finger hand; a restoration mechanism including a pushing platform, a cylinder and a guide rod. The restoration mechanism drives a push rod through the cylinder to realize the up-and-down movement of the pushing platform; the restoration mechanism is used to make the flexible three-finger hand return to the open state; a driving mechanism is used to realize the adjustment of the trigger force and grasping force and the unfolding and restoration of the flexible three-finger hand. The present invention has a fast response speed and can realize the rapid switching between the open and closed states.

Description

Technical Field

[0001] The present invention belongs to the field of robotic end effectors, and particularly relates to a fast-response flexible three-finger hand based on a bistable mechanism. Background Art

[0002] In recent years, with the continuous innovation of new intelligent materials and 3D printing technology, the application and research of flexible robots have become increasingly popular. Due to its own characteristics, a flexible robot has infinite degrees of freedom and continuous deformation ability, and can perform large-amplitude deformation actions such as torsion, bending, and stretching.

[0003] Therefore, flexible robots have broad applications in fields such as medical collaboration, disaster relief and rescue, home service, space repair, and agricultural picking. Among them, the flexible manipulator is a direction with a clear application prospect and high research value in flexible robots. Compared with a rigid manipulator, a flexible manipulator has a simple structure, light weight, and flexible application scenarios, and can be used to grasp objects of various shapes and sizes. In addition, the flexible manipulator has significant grasping advantages for soft objects that are prone to deformation, brittle objects that are fragile, and objects with irregular shapes. Due to the soft material, the flexible manipulator has a certain self-adaptability and can form an envelope around the object to be grasped when grasping the object. On the one hand, this can improve the tolerance of the shape of the object to be grasped, on the other hand, it will not cause damage to the object surface, and the grasping reliability is also improved compared with the rigid manipulator.

[0004] However, due to the relatively soft material and structure of the flexible manipulator, the response time of the flexible claw is relatively large, which makes it difficult for the flexible claw to be competent for the dynamic grasping task of high-speed moving objects, such as grasping a table tennis ball, tennis ball, baseball, etc. moving at a high speed (speed range is 3 - 10 m / s).

[0005] Therefore, in order to achieve fast-response dynamic grasping, how to provide a fast-response flexible three-finger hand based on a bistable mechanism has become a problem that needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the present invention provides a fast-response flexible three-finger hand based on a bistable mechanism. The present invention has a fast response speed, can realize fast switching between two states, and does not require additional energy to maintain the state.

[0007] In order to achieve the above object, the present invention adopts the following technical solution: A fast-response flexible three-finger hand based on a bistable mechanism, comprising:

[0008] A force adjustment mechanism, the force adjustment mechanism is installed on the robotic arm, and the force adjustment mechanism is used to adjust the trigger sensitivity and grasping force of the flexible three-finger hand;

[0009] Bi-stable mechanism, the bi-stable mechanism includes a pressing mechanism, an elastic mechanism and a connecting mechanism. The connecting mechanism is arranged between the elastic mechanisms. One end of the elastic mechanism is arranged on the pressing mechanism, and the other end of the elastic mechanism is installed on the force adjustment mechanism. The bi-stable mechanism is used to keep the flexible three-finger hand in the grasping and opening states;

[0010] Grasping mechanism, the grasping mechanism is installed on the pressing mechanism. The grasping mechanism includes three flexible fingers, and the three flexible fingers are evenly arranged in a circle. Each flexible finger has three phalanges and can realize the adaptive grasping of objects with various shapes;

[0011] Restoring mechanism, the restoring mechanism is installed on the force adjustment mechanism. The restoring mechanism includes a pushing platform, a cylinder and a guide rod. The cylinder is installed on the force adjustment mechanism. The push rod and the guide rod of the cylinder are both slidably connected to the force adjustment mechanism. The pushing platform is installed at one end of the push rod and the guide rod. The restoring mechanism drives the push rod through the cylinder to realize the up and down movement of the pushing platform. The restoring mechanism is used to make the flexible three-finger hand restore to the opening state;

[0012] Driving mechanism, the driving mechanism is installed on the force adjustment mechanism. The driving mechanism is used to drive and realize the adjustment of the triggering force and the grasping force.

[0013] Furthermore, the flexible finger includes a fingertip, a second phalanx, a third phalanx, a connecting piece, a first link, a second link, a spring and a support. The fingertip, the second phalanx and the third phalanx are sequentially rotatably connected. The third phalanx is rotatably connected to the pressing mechanism. The connecting piece is arranged between the second phalanx and the third phalanx. One end of the first link is rotatably connected to the fingertip, and the other end of the first link is rotatably connected to the connecting piece. One end of the second link is rotatably connected to the connecting piece, and the other end of the second link is rotatably connected to the support. The support is fixedly connected to the force adjustment mechanism. Springs are arranged between the fingertip and the second phalanx, and between the connecting piece and the third phalanx for the transmission of the pulling force and the restoration of the positions of the first link and the second link.

[0014] Furthermore, the pressing mechanism includes a pressing platform, a pulling link, a central moving part and a pressure spring. The pressing platform is connected to the pulling link and the third phalanx through a pin shaft. An extension rod is arranged at the top of the central moving part. The extension rod passes through the pulling link and is slidably connected to the pulling link. A protrusion is arranged at the top end of the extension rod. The pressure spring is slidably sleeved on the extension rod. The pressure spring is arranged between the protrusion and the pulling link.

[0015] Further, the connecting mechanism is arranged between the elastic mechanisms. The elastic mechanisms include spring plates, reinforcing plates, compression springs and screws. One end of the spring plate is fixedly connected to the central moving part, and the other end of the spring plate is fixedly connected to the connecting mechanism. The reinforcing plate is arranged at the central position of the spring plate. The screw is arranged on the side of the connecting mechanism away from the spring plate. The screw is fixedly connected to the force adjusting mechanism. The compression spring is slidably sleeved on the screw. The compression spring is arranged between the connecting mechanism and the force adjusting mechanism.

[0016] Further, the force adjusting mechanism includes a bottom flange, a turntable, a third connecting rod, a linear guide rail, a ball slider and an adjusting column. The turntable is arranged on the bottom flange. The turntable is rotatably connected to the bottom flange. The linear guide rail is arranged on the upper surface of the bottom flange. The ball slider is slidably connected to the linear guide rail. The adjusting column is arranged above the ball slider. One end of the third connecting rod is rotatably connected to the turntable, and the other end of the third connecting rod is rotatably connected to the adjusting column. The support is fixed to the top end of the adjusting column. The adjusting column is of a hollow structure. The screw is arranged in the adjusting column and fixedly connected to the adjusting column.

[0017] Further, the connecting mechanism includes a clamping member and a horizontal slider. The clamping member is rotatably connected to the horizontal slider. The clamping member is fixedly connected to the spring plate. The screw passes through the horizontal slider and is slidably connected to the horizontal slider. The screw is fixed in the adjusting column. The compression spring is arranged between the horizontal slider and the adjusting column.

[0018] Further, three side plates are equally divided on the edge of the pushing platform. The cylinder is arranged at the bottom end of the bottom flange. The ejector rod of the cylinder is fixedly connected to the side plate. The guide rod is slidably arranged on the bottom flange. The guide rod is fixedly connected to the other side plate.

[0019] Further, the driving mechanism includes a worm and worm gear reduction motor, a motor frame, a motor fixing housing and a flange connector. The worm and worm gear reduction motor is installed on the motor frame. The motor frame is fixed to the motor fixing housing. The motor fixing housing is fixedly connected to the bottom flange. The output shaft of the worm and worm gear reduction motor passes through the bottom flange and is fixedly connected to the turntable through the flange connector.

[0020] The beneficial effects of the present invention are as follows:

[0021] The flexible three-finger hand in the present invention can reliably stay in either the open or closed state without the need for continuous input of energy to maintain. It can be quickly switched between the two states through a driving device, with a fast response speed, reducing or even eliminating the signal transmission and processing of traditional flexible manipulator systems, reducing the response time of power components, and the grasping force can be adjusted through a force adjustment mechanism, making it well applicable to the design and manufacturing of fast-response flexible grippers. Brief Description of the Drawings

[0022] Figure 1 It is a schematic diagram of the main structure of the present invention;

[0023] Figure 2 It is a schematic diagram of the flexible finger structure of the present invention;

[0024] Figure 3 It is a schematic diagram of the flexible finger structure from another angle of the present invention;

[0025] Figure 4 It is a schematic diagram of the pressing structure of the present invention;

[0026] Figure 5 It is a schematic diagram of the elastic mechanism and connection mechanism of the present invention;

[0027] Figure 6 It is a schematic diagram of the force adjustment mechanism of the present invention;

[0028] Figure 7 It is a front view of the driving mechanism and restoration mechanism of the present invention;

[0029] Figure 8 It is a schematic diagram of the restoration mechanism of the present invention.

[0030] In the figures: 1 - flexible finger; 101 - fingertip; 102 - second phalanx; 103 - third phalanx; 104 - adapter; 105 - first connecting rod; 106 - second connecting rod; 107 - support; 2 - pressing mechanism; 201 - pressing platform; 202 - pulling connecting rod; 203 - central moving part; 204 - extending rod; 205 - pressure spring; 3 - elastic mechanism; 301 - spring plate; 302 - reinforcement plate; 303 - compression spring; 304 - screw; 4 - connection mechanism; 401 - clamping part; 402 - horizontal slider; 5 - force adjustment mechanism; 501 - bottom flange; 502 - turntable; 503 - third connecting rod; 504 - linear guide; 505 - ball slider; 506 - adjusting column; 6 - restoration mechanism; 601 - pushing platform; 602 - cylinder; 603 - guide rod; 7 - driving mechanism; 701 - worm and gear reduction motor; 702 - motor frame; 703 - motor fixing housing; 704 - flange connector. Detailed Embodiments

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0032] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "horizontal", "inner", "outer", "one side", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention; the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. In addition, unless otherwise clearly defined and limited, the terms "installation", "connection", "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0033] Embodiment 1

[0034] As Figures 1 to 8 shown, the present invention provides a fast-response flexible three-finger hand based on a bistable mechanism, including a grasping mechanism, a bistable mechanism, a force adjustment mechanism 5, a restoration mechanism 6, and a driving mechanism 7.

[0035] The grasping mechanism includes three flexible fingers 1, as Figures 1 to 3As shown, three flexible fingers 1 are evenly arranged in a circle. The flexible fingers 1 adopt an underactuated design. Each flexible finger 1 has three phalanges, mimicking the way a human hand grasps an object, and can achieve adaptive grasping of objects with various shapes and sizes. Due to the underactuation of the flexible fingers 1, the flexible fingers 1 have two grasping modes, which are jointly determined by the position of the central part and the shape of the object to be grasped. The flexible finger 1 includes a fingertip 101, a second phalanx 102, a third phalanx 103, an adapter 104, a first link 105, a second link 106, a spring, and a support 107. Pin holes are provided at both ends of the fingertip 101, the second phalanx 102, and the third phalanx 103, and they are sequentially rotatably connected by slotted pins. The third phalanx 103 is rotatably connected to the pressing mechanism 2 of the bistable mechanism. The adapter 104 is arranged between the second phalanx 102 and the third phalanx 103. One end of the first link 105 is rotatably connected to the fingertip 101, and the other end of the first link 105 is rotatably connected to the adapter 104. One end of the second link 106 is rotatably connected to the adapter 104, and the other end of the second link 106 is rotatably connected to the support 107. The support 107 is fixedly connected to the force adjustment mechanism 5. Springs are provided between the fingertip 101 and the second phalanx 102, and between the adapter 104 and the third phalanx 103, which are equivalent to the tendons of a human finger, for the transmission of tensile force and the restoration of the positions of the first link 105 and the second link 106.

[0036] The bistable mechanism includes a pressing mechanism 2, an elastic mechanism 3, and a connecting mechanism 4, which are used to maintain the grasping and opening states of the flexible three-finger hand, as Figure 4 shown. The pressing mechanism 2 includes a pressing platform 201, a pulling link 202, a central moving part 203, and a pressure spring 205. The pressing platform 201 is connected to the pulling link 202 by a pin shaft. An extension rod 204 is provided at the top of the central moving part 203. The extension rod 204 passes through the pulling link 202 and is slidably connected to the pulling link 202. A protrusion and a gasket are provided at the top end of the extension rod 204. The pressure spring 205 is slidably sleeved on the extension rod 204, and the pressure spring 205 is arranged between the protrusion and the pulling link 202.

[0037] As Figure 5As shown, the connecting mechanism 4 is arranged between the elastic mechanisms 3. The connecting mechanism 4 includes a clamping member 401 and a horizontal slider 402. The clamping member 401 is rotatably connected to the horizontal slider 402. The elastic mechanism 3 includes a spring plate 301, a reinforcement plate 302, a compression spring 303 and a screw 304. One end of the spring plate 301 is fixedly connected to the central moving member 203, and the other end of the spring plate 301 is fixedly connected to the clamping member 401. The reinforcement plate 302 is fixedly installed at the central position of the spring plate 301. In this embodiment, the spring plate 301 is formed by overlapping two spring sheets with a thickness of 0.2 mm. The screw 304 passes through the horizontal slider 402 and is slidably connected to the horizontal slider 402. The screw 304 is fixedly connected to the force adjustment mechanism 5. The compression spring 303 is slidably sleeved on the screw 304, and the compression spring 303 is arranged between the horizontal slider 402 and the force adjustment mechanism 5.

[0038] When the bistable mechanism is in the stable state where the flexible finger 1 is unfolded, an object contacts and presses the pressing platform 201, giving the pressing platform 201 a downward thrust, pushing the bistable mechanism over the transition point. Under the combined action of the elastic forces of the spring plate 301 and the compression spring 303, the central moving member 203 is driven to move downward. This driving force is transmitted to the pulling link 202 through the pressure spring 205, and the pulling link 202 will then pull the flexible finger 1 to achieve grasping.

[0039] The bistable mechanism is the main structure for realizing the bistable drive of the flexible three-finger hand. The sudden jump of the bistable state mainly relies on the shape change of the spring plate 301 and the compression spring 303 to realize the change of potential energy, thereby realizing the transition between the two stable states. The reinforcement plate 302 clamps the spring plate 301 with screws to reduce the deformation of the clamped part of the spring plate 301, so as to improve the stability of the movement. This part is a combination of a bistable beam and a bistable link-slider mechanism, which not only reduces the constraint mechanism but also increases the stability of the movement.

[0040] The force adjustment mechanism 5 is used to adjust the trigger sensitivity and grasping force of the flexible three-finger hand, such as Figure 6 As shown, the force adjustment mechanism 5 includes a bottom flange 501, a turntable 502, a third link 503, a linear guide 504, a ball slider 505 and an adjustment column 506. The turntable 502 is arranged on the bottom flange 501, and the turntable 502 is rotatably connected to the bottom flange 501. The linear guide 504 is arranged on the upper surface of the bottom flange 501. The ball slider 505 is slidably connected to the linear guide 504. The adjustment column 506 is fixed above the ball slider 505. One end of the third link 503 is rotatably connected to the turntable 502, and the other end of the third link 503 is rotatably connected to the adjustment column 506. The support 107 is fixed at the top of the adjustment column 506. The adjustment column 506 is a hollow structure, and the screw 304 is arranged in the adjustment column 506 and is fixedly connected to the adjustment column 506.

[0041] By driving the turntable 502 to rotate, the third connecting rod 503 can convert the rotation into the forward and backward sliding of the adjusting column 506. By moving the adjusting column 506, not only can the stable state position of the bistable mechanism be adjusted, thereby adjusting the triggering sensitivity and grasping force of the grasping; but also the relative position of the grasping part can be adjusted to achieve the adjustment of the grasping tightness of the gripper. When the adjusting column 506 is closer to the center of the turntable 502, the triggering force for the flexible finger 1 to achieve grasping and the grasping force generated by the flexible finger 1 are greater; conversely, the farther away from the center of the turntable 502, the smaller the triggering force and the grasping force.

[0042] As Figures 7 to 8 shown, the restoring mechanism 6 includes a pushing platform 601, a cylinder 602 and a guide rod 603. The restoring mechanism 6 drives the ejector rod through the cylinder 602 to realize the up and down movement of the pushing platform 601. The restoring mechanism 6 is used to make the flexible three-finger hand return to the open state. Three side plates are equally divided on the edge of the pushing platform 601. The cylinder 602 is arranged at the bottom end of the bottom flange 501. The ejector rod of the cylinder 602 is fixedly connected with the side plate. The guide rod 603 is slidably arranged on the bottom flange 501, and the guide rod 603 is fixedly connected with other side plates.

[0043] When the pushing platform 601 moves upward, it can lift the central moving part 203 of the bistable mechanism, thereby realizing the opening of the flexible finger 1, that is, restoring to the initial stable state position. After the restoration process is completed, the pushing platform 601 moves downward under the drive of the cylinder ejector rod and returns to the initial position to prevent hindering the sudden jump change of the bistable mechanism.

[0044] The driving mechanism 7 is used to drive and realize the adjustment of the triggering force and the grasping force. The driving mechanism 7 includes a worm and worm gear reduction motor 701, a motor frame 702, a motor fixed housing 703 and a flange connector 704. The worm and worm gear reduction motor 701 is installed on the motor frame 702, the motor frame 702 is fixed on the motor fixed housing 703, the motor fixed housing 703 is fixedly connected with the bottom flange 501, and the output shaft of the worm and worm gear reduction motor 701 passes through the bottom flange 501 and is fixedly connected with the turntable 502 through the flange connector 704.

[0045] The driving of the force adjustment mechanism 5 is driven by the worm and worm gear reduction motor 701. When the output shaft of the worm and worm gear reduction motor 701 rotates counterclockwise, the turntable 502 rotates counterclockwise, thereby increasing the triggering force for the flexible finger 1 to achieve grasping and the grasping force generated by the flexible finger 1. The driving of the restoring mechanism 6 is driven by the cylinder 602, and the reciprocating linear motion of the ejector rod is realized through pneumatic means, thereby driving the pushing platform 601 to complete the restoration action.

[0046] The above are only the preferred embodiments of the present invention, and do not impose any limitation on the technical scope of the present invention. Therefore, any minor modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A fast-response flexible three-finger hand based on a bistable mechanism, characterized in that: It includes: A force adjustment mechanism, which is installed on the robotic arm and is used to adjust the trigger sensitivity and grasping force of the flexible three-finger hand; A bistable mechanism, which includes a pressing mechanism, an elastic mechanism and a connecting mechanism. The connecting mechanism is arranged between the elastic mechanisms. One end of the elastic mechanism is arranged on the pressing mechanism, and the other end of the elastic mechanism is installed on the force adjustment mechanism. The bistable mechanism is used to maintain the grasping and opening states of the flexible three-finger hand; A grasping mechanism, which is installed on the pressing mechanism. The grasping mechanism includes three flexible fingers, and the three flexible fingers are evenly arranged in a circle. Each flexible finger has three phalanges and can realize the adaptive grasping of objects with various shapes; A restoration mechanism, which is installed on the force adjustment mechanism. The restoration mechanism includes a pushing platform, a cylinder and a guide rod. The cylinder is installed on the force adjustment mechanism. The ejector rod and the guide rod of the cylinder are both slidably connected to the force adjustment mechanism. The pushing platform is installed at one end of the ejector rod and the guide rod. The restoration mechanism drives the ejector rod through the cylinder to realize the up and down movement of the pushing platform. The restoration mechanism is used to make the flexible three-finger hand return to the open state; A driving mechanism, which is installed on the force adjustment mechanism and is used to drive and realize the adjustment of the trigger force and the grasping force; The pressing mechanism includes a pressing platform, a pulling connecting rod, a central moving part and a pressure spring. The pressing platform is connected to the pulling connecting rod and the flexible finger through a pin shaft. An extending rod is arranged at the top of the central moving part. The extending rod passes through the pulling connecting rod and is slidably connected to the pulling connecting rod. A protrusion is arranged at the top end of the extending rod. The pressure spring is slidably sleeved on the extending rod, and the pressure spring is arranged between the protrusion and the pulling connecting rod; The connecting mechanism is arranged between the elastic mechanisms. The elastic mechanism includes a spring plate, a reinforcing plate, a compression spring and a screw. One end of the spring plate is fixedly connected to the central moving part, and the other end of the spring plate is fixedly connected to the connecting mechanism. The reinforcing plate is arranged at the central position of the spring plate. The screw is arranged on the side of the connecting mechanism away from the spring plate, and the screw is fixedly connected to the force adjustment mechanism. The compression spring is slidably sleeved on the screw, and the compression spring is arranged between the connecting mechanism and the force adjustment mechanism; The force adjustment mechanism includes a bottom flange, a turntable, a third connecting rod, a linear guide rail, a ball slider and an adjustment column. The turntable is arranged on the bottom flange, and the turntable is rotatably connected to the bottom flange. The linear guide rail is arranged on the upper surface of the bottom flange. The ball slider is slidably connected to the linear guide rail. The adjustment column is arranged above the ball slider. One end of the third connecting rod is rotatably connected to the turntable, and the other end of the third connecting rod is rotatably connected to the adjustment column. A support is fixed at the top end of the adjustment column. The adjustment column is a hollow structure, and the screw is arranged in the adjustment column and is fixedly connected to the adjustment column; The connecting mechanism includes a clamping piece and a horizontal slider, the clamping piece is rotatably connected to the horizontal slider, the clamping piece is fixedly connected to the spring plate, the screw passes through the horizontal slider and is slidably connected to the horizontal slider, the screw is fixed in the adjusting column, and the compression spring is arranged between the horizontal slider and the adjusting column.

2. According to claim 1, a fast-response flexible three-finger hand based on a bistable mechanism, It is characterized in that The flexible finger includes a fingertip, a second section of the knuckle, a third section of the knuckle, an adapter, a first connecting rod, a second connecting rod, a spring and a support. The fingertip, the second section of the knuckle and the third section of the knuckle are rotationally connected in sequence, the third section of the knuckle is rotationally connected to a pressing mechanism, the adapter is arranged between the second section of the knuckle and the third section of the knuckle, one end of the first connecting rod is rotationally connected to the fingertip, the other end of the first connecting rod is rotationally connected to the adapter, one end of the second connecting rod is rotationally connected to the adapter, the other end of the second connecting rod is rotationally connected to the support, the support is fixedly connected to the force adjustment mechanism, and springs are arranged between the fingertip and the second section of the knuckle and between the adapter and the third section of the knuckle for transmitting tension and restoring the positions of the first connecting rod and the second connecting rod.

3. According to claim 1, a fast-response flexible three-finger hand based on a bistable mechanism, It is characterized in that The edge of the pushing platform is equally divided into three side plates, the cylinder is arranged at the bottom end of the bottom flange, the top rod of the cylinder is fixedly connected to the side plate, the guide rod is slidably arranged on the bottom flange, and the guide rod is fixedly connected to other side plates.

4. According to claim 1, a fast-response flexible three-finger hand based on a bistable mechanism, It is characterized in that The driving mechanism includes a worm gear reduction motor, a motor frame, a motor fixing housing and a flange connector, the worm gear reduction motor is mounted on the motor frame, the motor frame is fixed on the motor fixing housing, the motor fixing housing is fixedly connected to the bottom flange, and the output shaft of the worm gear reduction motor passes through the bottom flange and is fixedly connected to the turntable through the flange connector.

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