Three-finger underactuated dexterous hand mechanism and operation method thereof

Abstract

The present invention provides a three-finger underactuated dexterous hand mechanism and an operation method thereof, which can realize the high dexterity of the three-finger dexterous hand and achieve the two functions of parallel clamping and compliant grasping, increase the multi-function and dexterity of the finger system, reduce the structural complexity caused by multi-finger redundancy, reduce the manufacturing cost, and improve the dexterity of on-track control. The single-finger mechanism uses a connecting rod mechanism to transmit the power source from the finger heel to the fingertip. The single finger is composed of three knuckles, which are the proximal knuckle, the middle knuckle, and the distal knuckle from bottom to top. When compliant grasping, the proximal knuckle contacts the object first, and the limiting mechanism at the proximal knuckle transfers the motion to the middle knuckle and the distal knuckle through opening and closing, and then the limiting mechanism at the middle knuckle also opens and closes to transfer the motion to the distal knuckle, and so on and so forth to achieve compliance with the shape of the object, and close and cover the grasped object in sequence. During the parallel clamping process, the limiting mechanism will not open and close, and then the two fingers perform a parallel clamping operation.

Description

Technical Field

[0001] The present invention relates to the field of mechanical claws, and in particular to a three-finger under-actuated dexterous hand mechanism and an operation method thereof, which are suitable for use at the end of a space station mechanical arm. Background Art

[0002] The end tool of the space manipulator refers to the corresponding tool installed at the end of the space station manipulator, which can be used to complete the corresponding space station on-orbit control tasks. When operating the existing space station manipulator end tool, a variety of different end tools are required to carry out on-orbit control tasks. Due to the complexity of the task, there are various types of tools, which occupy a large number of space station positions and the payload of the launch vehicle. With the development of science and technology, the end tool of space on-orbit control is gradually developing in the direction that a single tool can realize multiple functions. Summary of the invention

[0003] In order to solve the problems of the prior art, the present invention provides a three-finger under-actuated dexterous hand mechanism and an operation method thereof, which can realize the high dexterity of the three-finger dexterous hand and achieve the two functions of parallel clamping and compliant grasping, increase the multi-function and dexterity of the finger system, reduce the structural complexity caused by multi-finger redundancy, reduce the manufacturing cost, and improve the dexterity of on-track control.

[0004] The present invention provides a three-finger under-actuated dexterous hand mechanism, comprising a base, a transmission mechanism, three dexterous fingers, a transmission rod group and a limit mechanism;

[0005] One end of the base is connected to the robotic arm via a connector, and the other end is equipped with three dexterous fingers;

[0006] The dexterous finger comprises a base, a proximal knuckle, a middle knuckle and a distal knuckle connected in sequence, wherein the base is connected to the base, and the base, the proximal knuckle, the middle knuckle and the distal knuckle are connected by a horizontal connecting shaft, and a limiting mechanism is arranged at the connecting shaft;

[0007] The limiting mechanism includes a shaft sleeve, an elastic pressure piece, a spring and a transmission card wheel, wherein the shaft sleeve is sleeved on the connecting shaft and rotates with the connecting shaft, and a plurality of elastic pressure pieces and springs equidistantly distributed around the shaft sleeve are arranged on the outer surface of the shaft sleeve, the elastic pressure piece is fixedly connected to the shaft sleeve, one side of the spring is fixedly connected to the shaft sleeve, and the other side is fixedly connected to the elastic pressure piece; the finger joint above the connecting shaft is fixedly connected to the transmission card wheel, and a protrusion is arranged on the transmission card wheel. The elastic pressure piece and the protrusion part of the transmission card wheel act to drive the corresponding finger joint to rotate. When the corresponding finger joint contacts the grasped object and reaches a certain position, the spring is compressed, and the limiting mechanism no longer drives the corresponding finger joint to rotate, thereby realizing the position limitation of the corresponding finger joint;

[0008] The transmission rod group includes a first connecting rod fixedly connected to the base and the proximal knuckle connecting shaft, a third connecting rod fixedly connected to the proximal knuckle and the middle knuckle connecting shaft, a second connecting rod connecting the first connecting rod and the third connecting rod, and a fourth connecting rod connecting the third connecting rod and the distal knuckle, and the connections between the connecting rods are all hinge connections, and the fourth connecting rod and the distal knuckle are also hingedly connected;

[0009] The transmission mechanism is installed inside the base, and the transmission mechanism is respectively connected to the first connecting rod and the connecting shaft between the base and the proximal knuckle of the dexterous finger.

[0010] The transmission mechanism includes a motor, a reducer, a worm, a worm wheel, a gear set, a motor main bracket, a motor auxiliary bracket and a transmission belt, wherein the motor is fixedly connected to the base through the motor main bracket and the motor auxiliary bracket, and the motor transmits motion to the first connecting rod and the connecting shaft between the base and the proximal knuckle through the reducer, worm, turbine, gear set and transmission belt in turn.

[0011] The present invention also provides an operation method of a three-finger underactuated dexterous hand mechanism, including parallel clamping control and compliant grasping control;

[0012] In the compliant grasping control, the transmission mechanism controls the three dexterous fingers to rotate simultaneously to approach the object, so that the proximal knuckle, middle knuckle and distal knuckle conform to the shape of the object to grasp the object;

[0013] In parallel clamping control, one of the dexterous fingers is fixed, and the transmission mechanism controls the other two dexterous fingers to perform parallel clamping.

[0014] In the above control process, the motion control method of a single dexterous finger is as follows:

[0015] Step 1: The transmission mechanism transmits the motion to the connecting shaft between the base and the proximal knuckle, thereby driving the limiting mechanism on the connecting shaft to rotate. The elastic pressing piece in the limiting mechanism and the raised part of the transmission card wheel act to drive the proximal knuckle to rotate; when the proximal knuckle contacts the grasped object and reaches a certain position, the spring-pressed limiting mechanism no longer drives the proximal knuckle to rotate, thereby limiting the position of the proximal knuckle. During the above process, the relative positions of the knuckle and the distal knuckle and the proximal knuckle remain unchanged;

[0016] Step 2: The transmission mechanism transmits the motion to the first connecting rod, driving the first connecting rod to rotate, the first connecting rod drives the second connecting rod to rotate, the second connecting rod drives the third connecting rod to rotate, the third connecting rod drives the limiting mechanism between the proximal phalanx and the middle phalanx to rotate, the elastic pressing piece in the limiting mechanism and the raised part of the transmission card wheel act to drive the middle phalanx to rotate, when the middle phalanx contacts the grasped object and reaches a certain position, the spring is compressed, and the limiting mechanism no longer drives the middle phalanx to rotate, thereby realizing the position restriction of the middle phalanx; in the above process, the relative position of the distal phalanx and the middle phalanx remains unchanged;

[0017] Step 3: The third link drives the fourth link to rotate, and the fourth link drives the distal knuckle to rotate; when the distal knuckle touches the object and reaches a certain position, the servo motor stops rotating, and the entire single-finger movement process is completed.

[0018] When the three fingers complete the above movement steps, the object is grasped.

[0019] The beneficial effects of the present invention are:

[0020] 1. It can realize the high dexterity of the three-finger dexterous hand and achieve the two functions of parallel clamping and compliant grasping, increase the multi-function and dexterity of the finger system, reduce the structural complexity caused by multi-finger redundancy, reduce the production cost, and improve the dexterity of on-orbit control.

[0021] 2. A limit mechanism is designed. The transmission card wheel is fixedly connected to the corresponding knuckle. The elastic pressure piece acts on the convex part of the transmission card wheel to drive the corresponding knuckle to rotate. When the corresponding knuckle contacts the grasped object and reaches a certain position, the spring is compressed, and the limit mechanism no longer drives the corresponding knuckle to rotate, thus limiting the position of the corresponding knuckle. Under-actuation is achieved while ensuring the stability of grasping.

[0022] 3. The servo motor drives the first connecting rod to rotate, the first connecting rod drives the second connecting rod to rotate, the second connecting rod drives the third connecting rod to rotate, the third connecting rod drives the middle finger joint limit mechanism and the fourth connecting rod to rotate, and the fourth connecting rod drives the distal finger joint to rotate. A complex transmission mechanism is avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 is a schematic structural diagram of a single dexterous finger of the present invention;

[0026] Figure 3 It is a structural cross-sectional view of a single dexterous finger of the present invention.

[0027] Figure 4 It is a schematic diagram of the transmission mechanism.

[0028] In the figure, base 1, proximal knuckle 2, middle knuckle 3, distal knuckle 4, connecting shaft 5, base 6, connector 7, limiting mechanism 8, transmission rod group 9, first connecting rod 91, second connecting rod 92, third connecting rod 93, and fourth connecting rod 94. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The structure of the present invention is as follows Figure 1-3 As shown, it includes a base 6, a transmission mechanism, three smart fingers, a transmission rod group and a limiting mechanism 8.

[0031] One end of the base 6 is connected to the robot arm via a connector 7, and the other end is equipped with three dexterous fingers;

[0032] The dexterous finger comprises a base 1, a proximal phalanx 2, a middle phalanx 3 and a distal phalanx 4 which are connected in sequence, wherein the base is connected to the base, and the base, the proximal phalanx, the middle phalanx and the distal phalanx are connected via a horizontal connecting shaft 5, and a limit mechanism is arranged at the connecting shaft, wherein the rotation between the base and the proximal phalanx of the dexterous finger is driven by an independent motor; the dexterous finger comprises a fixed finger and two movable fingers, the base of the fixed finger is fixedly connected to the base, and the base of the movable finger rotates on the surface of the base under the control of a transmission mechanism;

[0033] The limiting mechanism includes a shaft sleeve, an elastic pressure piece, a spring and a transmission card wheel, wherein the shaft sleeve is sleeved on the connecting shaft and rotates with the connecting shaft, and a plurality of elastic pressure pieces and springs equidistantly distributed around the shaft sleeve are arranged on the outer surface of the shaft sleeve, the elastic pressure piece is fixedly connected to the shaft sleeve, one side of the spring is fixedly connected to the shaft sleeve, and the other side is fixedly connected to the elastic pressure piece; the finger joint above the connecting shaft is fixedly connected to the transmission card wheel, and a protrusion is arranged on the transmission card wheel. The elastic pressure piece and the protrusion part of the transmission card wheel act to drive the corresponding finger joint to rotate. When the corresponding finger joint contacts the grasped object and reaches a certain position, the spring is compressed, and the limiting mechanism no longer drives the corresponding finger joint to rotate, thereby realizing the position limitation of the corresponding finger joint;

[0034] The transmission rod group includes a first connecting rod 91 fixedly connected to the base and the proximal knuckle connecting shaft, a third connecting rod 93 fixedly connected to the proximal knuckle and the middle knuckle connecting shaft, a second connecting rod 92 connecting the first connecting rod and the third connecting rod, and a fourth connecting rod 94 connecting the third connecting rod and the distal knuckle. The connections between the connecting rods are all hinged connections, and the fourth connecting rod and the distal knuckle are also hinged.

[0035] The transmission mechanism is installed inside the base, and the transmission mechanism is respectively connected to the first connecting rod and the connecting shaft between the base and the proximal knuckle of the dexterous finger.

[0036] The transmission mechanism is as follows Figure 4As shown, it includes a motor, a reducer, a worm, a worm wheel, a gear set, a transmission shaft, a motor main bracket, a motor auxiliary bracket and a transmission belt, wherein the motor is fixedly connected to the base through the motor main bracket and the motor auxiliary bracket, the motor drives the two transmission shafts to rotate through the reducer, the worm, the turbine, the gear set and the transmission belt, and the two transmission shafts drive the movable fingers to rotate.

[0037] An operating method of a three-finger underactuated dexterous hand mechanism, including parallel clamping control and compliant grasping control;

[0038] In the compliant grasping control, the transmission mechanism controls the three dexterous fingers to rotate simultaneously to approach the object, so that the proximal knuckle, middle knuckle and distal knuckle conform to the shape of the object to grasp the object;

[0039] In parallel clamping control, the fixed finger is fixed and the transmission mechanism controls the two movable fingers to perform parallel clamping.

[0040] In the above control process, the motion control method of a single dexterous finger is as follows:

[0041] Step 1: The transmission mechanism transmits the motion to the connecting shaft between the base and the proximal knuckle, thereby driving the limiting mechanism on the connecting shaft to rotate. The elastic pressing piece in the limiting mechanism and the raised part of the transmission card wheel act to drive the proximal knuckle to rotate; when the proximal knuckle contacts the grasped object and reaches a certain position, the spring-pressed limiting mechanism no longer drives the proximal knuckle to rotate, thereby limiting the position of the proximal knuckle. During the above process, the relative positions of the knuckle and the distal knuckle and the proximal knuckle remain unchanged;

[0042] Step 2: The transmission mechanism transmits the motion to the first connecting rod, driving the first connecting rod to rotate, the first connecting rod drives the second connecting rod to rotate, the second connecting rod drives the third connecting rod to rotate, the third connecting rod drives the limiting mechanism between the proximal phalanx and the middle phalanx to rotate, the elastic pressing piece in the limiting mechanism and the raised part of the transmission card wheel act to drive the middle phalanx to rotate, when the middle phalanx contacts the grasped object and reaches a certain position, the spring is compressed, and the limiting mechanism no longer drives the middle phalanx to rotate, thereby realizing the position restriction of the middle phalanx; in the above process, the relative position of the distal phalanx and the middle phalanx remains unchanged;

[0043] Step 3: The third link drives the fourth link to rotate, and the fourth link drives the distal knuckle to rotate; when the distal knuckle touches the object and reaches a certain position, the servo motor stops rotating, and the entire single-finger movement process is completed.

[0044] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, the above is only a preferred embodiment of the present invention. Since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field is within the technical scope disclosed by the present invention. For ordinary technicians in the technical field, changes or replacements that can be easily thought of should be covered within the protection scope of the present invention without departing from the principle of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A three-finger underactuated dexterous hand mechanism, characterized in that: It includes a base, a transmission mechanism, three smart fingers, a transmission rod group and a limit mechanism; One end of the base is connected to the robotic arm via a connector, and the other end is equipped with three dexterous fingers; The dexterous finger comprises a base, a proximal phalanx, a middle phalanx and a distal phalanx connected in sequence, wherein the base is connected to the base, and the base, the proximal phalanx, the middle phalanx and the distal phalanx are connected by a horizontal connecting shaft, and a limit mechanism is arranged at the connecting shaft, wherein the rotation between the base and the proximal phalanx of the dexterous finger is driven by an independent motor; the dexterous finger comprises a fixed finger and two movable fingers, the base of the fixed finger is fixedly connected to the base, and the base of the movable finger rotates on the surface of the base under the control of the transmission mechanism; The limiting mechanism includes a shaft sleeve, an elastic pressure piece, a spring and a transmission card wheel, wherein the shaft sleeve is sleeved on the connecting shaft and rotates with the connecting shaft, and a plurality of elastic pressure pieces and springs equidistantly distributed around the shaft sleeve are arranged on the outer surface of the shaft sleeve, the elastic pressure piece is fixedly connected to the shaft sleeve, one side of the spring is fixedly connected to the shaft sleeve, and the other side is fixedly connected to the elastic pressure piece; the finger joint above the connecting shaft is fixedly connected to the transmission card wheel, and a protrusion is arranged on the transmission card wheel. The elastic pressure piece and the protrusion part of the transmission card wheel act to drive the corresponding finger joint to rotate. When the corresponding finger joint contacts the grasped object and reaches a certain position, the spring is compressed, and the limiting mechanism no longer drives the corresponding finger joint to rotate, thereby realizing the position limitation of the corresponding finger joint; The transmission rod group includes a first connecting rod fixedly connected to the base and the proximal knuckle connecting shaft, a third connecting rod fixedly connected to the proximal knuckle and the middle knuckle connecting shaft, a second connecting rod connecting the first connecting rod and the third connecting rod, and a fourth connecting rod connecting the third connecting rod and the distal knuckle, and the connections between the connecting rods are all hinge connections, and the fourth connecting rod and the distal knuckle are also hingedly connected; The transmission mechanism is installed inside the base, and the transmission mechanism is respectively connected to the first connecting rod and the connecting shaft between the base and the proximal knuckle of the dexterous finger.

2. The three-finger under-actuated dexterous hand mechanism according to claim 1, characterized in that: The transmission mechanism includes a motor, a reducer, a worm, a worm wheel, a gear set, a transmission shaft, a motor main bracket, a motor auxiliary bracket and a transmission belt, wherein the motor is fixedly connected to the base through the motor main bracket and the motor auxiliary bracket, the motor drives the two transmission shafts to rotate through the reducer, the worm, the turbine, the gear set and the transmission belt, and the two transmission shafts drive the movable fingers to rotate.

3. A method for operating a three-finger under-actuated dexterous hand mechanism, using the three-finger under-actuated dexterous hand mechanism of claim 1, characterized in that: Includes parallel grip control and compliant grip control; In the compliant grasping control, the transmission mechanism controls the three dexterous fingers to rotate simultaneously to approach the object, so that the proximal knuckle, middle knuckle and distal knuckle conform to the shape of the object to grasp the object; In parallel clamping control, the fixed finger is fixed and the transmission mechanism controls the two movable fingers to perform parallel clamping; During the above parallel gripping control and compliant grasping control processes, the motion control method of a single dexterous finger is as follows: Step 1: The transmission mechanism transmits the motion to the connecting shaft between the base and the proximal knuckle, thereby driving the limiting mechanism on the connecting shaft to rotate. The elastic pressing piece in the limiting mechanism and the raised part of the transmission card wheel act to drive the proximal knuckle to rotate; when the proximal knuckle contacts the grasped object and reaches a certain position, the spring-pressed limiting mechanism no longer drives the proximal knuckle to rotate, thereby limiting the position of the proximal knuckle. During the above process, the relative positions of the knuckle and the distal knuckle and the proximal knuckle remain unchanged; Step 2: The transmission mechanism transmits the motion to the first connecting rod, driving the first connecting rod to rotate, the first connecting rod drives the second connecting rod to rotate, the second connecting rod drives the third connecting rod to rotate, the third connecting rod drives the limiting mechanism between the proximal phalanx and the middle phalanx to rotate, the elastic pressing piece in the limiting mechanism and the raised part of the transmission card wheel act to drive the middle phalanx to rotate, when the middle phalanx contacts the grasped object and reaches a certain position, the spring is compressed, and the limiting mechanism no longer drives the middle phalanx to rotate, thereby realizing the position restriction of the middle phalanx; in the above process, the relative position of the distal phalanx and the middle phalanx remains unchanged; Step 3: The third link drives the fourth link to rotate, and the fourth link drives the distal knuckle to rotate; when the distal knuckle touches the object and reaches a certain position, the servo motor stops rotating, and the entire single-finger movement process is completed.

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