Negative-pressure suction cup dexterous hand for grabbing flexible materials and grabbing method of negative-pressure suction cup dexterous hand

Abstract

The invention discloses a negative pressure suction cup dexterous hand used for grabbing flexible materials and a grabbing method, the dexterous hand comprises a base and three fingers evenly distributed in the circumferential direction, each finger is formed by sequentially hinging a far finger end, a middle finger end and a near finger end, and each joint is driven by an independent motor to achieve pitching or swinging motion. The finger pulp of the far finger end is provided with an array type negative pressure suction cup, the finger back is provided with an independent air path connector, the suction cups of all the fingers are connected in parallel through air pipes and then connected to a shared negative pressure adjusting valve and a vacuum source, and unified adjustment of air pressure is achieved. The suction cup can be attached to a complex curved surface in a self-adaptive mode by independently controlling all fingers and all knuckles to move; the negative pressure of the suction cups is adjusted on the basis of the material of the cloth, and efficient and lossless separation of single layers in the stacked cloth can be achieved; and after separation, the fingers can be cooperatively folded to form wrapping type stable grasping of the cloth. The problems that the flexible thin-layer material is difficult to separate and unstable to grab in the automatic grabbing process are solved.

Description

Technical Field

[0001] This invention relates to the field of robotics, and more specifically to a negative pressure suction cup dexterous hand for grasping flexible materials and its grasping method. Background Technology

[0002] In the fields of apparel and textiles, logistics sorting, and domestic services, there is a growing demand for automated gripping and handling of flexible materials such as fabrics and leather. These materials are characterized by their susceptibility to deformation, smooth surfaces, and tendency to stick together when stacked, posing a significant challenge to the stable gripping capabilities of robots.

[0003] Traditional rigid grippers are prone to causing wrinkles and scratches on fabrics during gripping, and they struggle to separate individual layers from a stack of fabric. While simple negative pressure suction cup grippers can achieve surface adhesion, they are ineffective at separating stacked fabrics, and during handling after gripping, the fabric is prone to detachment due to its hanging position and susceptibility to airflow disturbances. Existing humanoid dexterous hands, although offering high degrees of freedom, are structurally complex, costly, and lack specific designs for separating and stably gripping flexible materials, making them difficult to widely apply in industrial settings. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a negative pressure suction cup dexterous hand with a compact structure, reliable gripping, and particularly suitable for separating and gripping stacked flexible materials, as well as its gripping method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a dexterous hand with a negative pressure suction cup for grasping flexible materials, comprising a base and three fingers evenly distributed circumferentially. Each finger includes a distal phalanx, a middle phalanx, and a proximal phalanx, which are hinged sequentially, with the proximal phalanx hinged to the base. Each joint is equipped with an independent motor: the motor controlling the pitch of the distal and middle phalanxes is horizontally arranged; the motor controlling the swing of the proximal phalanx is vertically mounted on the base. The distal phalanx has a negative pressure suction cup mounting structure on its fingertip, and an air tube socket connecting to the suction cup is provided on its back.

[0006] Furthermore, it also includes an air pressure regulation system, featuring a negative pressure regulating valve, air hoses connecting each suction cup, and a controller. The air hoses corresponding to each finger suction cup are combined and connected to the same negative pressure regulating valve. The controller can independently control each motor and uniformly control the negative pressure regulating valve based on the fabric material to regulate the common air pressure flow of all suction cups.

[0007] Furthermore, a rotating frame is provided between the proximal fingertip and the base. The first end of the rotating frame is fixed to the output shaft of the drive motor, and the second end is fixed to the proximal fingertip. The drive motor drives the proximal fingertip to swing through the rotating frame.

[0008] Furthermore, the rotating frame is an "L"-shaped or offset connecting rod, with the distance from its first end to the rotation center being less than the distance from its second end to the rotation center, so that the swing angle near the fingertip is greater than the rotation angle of the drive motor output shaft.

[0009] Furthermore, the three drive motors that drive the swinging motion of the three proximal fingertips are all mounted vertically and independently on the base and are distributed circumferentially around the base so that the swinging motion of each finger is independent of each other and without mechanical interference.

[0010] The present invention also provides a method for grasping stacked fabric using the above-mentioned dexterous hand, specifically including: S1: Independently controls the joint rotation between the proximal tip and base of each finger, adjusting the overall horizontal orientation of each finger; S2: Independently control the joint rotation of the distal and middle fingertips of each finger, so that the fingertip plane of the distal fingertips of each finger adapts to the fabric surface. S3: Based on the material information of the fabric to be grasped, control the air pressure flow of all negative pressure suction cups in a unified manner, and use the negative pressure suction cups on the negative pressure suction cup mounting structure to adsorb the top single layer of fabric. S4: Under the action of negative pressure adsorption, lift the dexterous hand to separate the adsorbed single layer of fabric from the lower layer; S5: Independently controls the movement of each joint of each finger, allowing each finger to close inward at different postures and angles, working together to hold the separated single layer of fabric. Adjusts the position and tilt angle of each finger to make the suction cup adhere to the fabric; adjusts the negative pressure according to the material and adsorbs the top layer of fabric; enhances dexterity in separating single layers; controls the fingers to close and wrap the fabric.

[0011] The beneficial effects of this invention are: 1. Excellent separation effect: The fingertip negative pressure suction cup can accurately adsorb single-layer fabric, and with the lifting action of a dexterous hand, it can effectively achieve the non-destructive separation of stacked fabrics.

[0012] 2. Stable and reliable gripping: The composite gripping strategy of "first adsorption and separation, then multi-finger wrapping" combines the advantages of negative pressure adsorption and anti-slip with mechanical clamping and anti-disturbance, making the handling process stable.

[0013] 3. Highly adaptable: Each finger and joint can be independently controlled to adapt to complex curved surfaces; the negative pressure is independently adjustable to match fabrics of different materials, thicknesses, and breathability.

[0014] 4. Large working space: The rotating frame transmission design enables large-angle swing near the fingertips, expanding the working envelope of the dexterous hand and enhancing its applicability.

[0015] 5. Compact and practical structure: The three drive motors are vertically and independently mounted on the base and distributed circumferentially, ensuring the independence of the movement of each finger. At the same time, the structure is compact and easy to apply in industrial applications. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the dexterous hand according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the distal fingertip structure according to an embodiment of the present invention (from both the fingertip and the back of the finger). Figure 3 This is a schematic diagram of the fingertip structure in an embodiment of the present invention; Figure 4 This is a schematic diagram of the proximal fingertip structure according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the rotating frame structure according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the drive motor structure according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the base structure according to an embodiment of the present invention; Figure 8 Schematic diagram of the suction cup mounting tooth structure; Figure 9 This is a schematic diagram of the motor end plate mounting structure; Figure 10 Schematic diagram of the process principle for controlling a dexterous hand Attached diagram labels: 1. distal fingertip; 2. middle fingertip; 3. proximal fingertip; 4. base; 5. suction cup mounting teeth; 6. motor mounting hole; 7. air pipe socket; 8. motor end plate mounting hole; 9. motor shaft mounting hole; 10. motor end plate; 11. vertical motor mounting hole; 12. rotating frame; 13. drive motor. Detailed Implementation

[0017] The following is in conjunction with the appendix Figures 1 to 10 The present invention provides a detailed description of the specific implementation of a negative pressure suction cup dexterous hand for grasping flexible materials and its grasping method.

[0018] like Figure 1 As shown, the negative pressure suction cup dexterous hand of this embodiment has a circular disc-shaped base 4 with three fingers arranged circumferentially on its upper surface in a 120-degree even distribution. Each finger consists of three segments: a distal end 1, a middle end 2, and a proximal end 3. Each segment is equipped with a drive motor 13 to control its movement. The distal end 1 and the middle end 2 move up and down, giving the fingers the ability to bend like human fingers; while the proximal end 3 swings and rotates around a vertical axis, allowing adjustment of the finger's position and effective grasping of various objects. The distal end 1 has a suction cup mounting structure at its fingertip and an air tube mounting structure at its back, connected to the suction cup mounting structure.

[0019] As shown in Figure 2 and Figure 3 shown, motor mounting seats are provided at the ends of both the distal finger tip 1 and the middle finger tip 2. Inside the motor mounting seat, there is a horizontally installed pitching drive motor 13. A number of motor mounting holes 6 are provided on the motor mounting seat for fixing the pitching drive motor. As shown in Figure 3 and Figure 4 shown, rotating connection mechanisms are provided on both sides of the ends of the middle finger tip 2 and the proximal finger tip 3. They are semi-circular connection structures, with motor end plate mounting holes 8 and motor shaft mounting holes 9 provided, for realizing the transmission of the driving motor power. A motor end plate 10 is fixedly connected to the output shaft of the pitching drive motor 13 and fixed to the rotating connection mechanism by screws, thereby transmitting the motor torque to the next finger joint to drive its rotation.

[0020] As shown in Figure 6 shown, a motor end plate 10 is fixed to the output end of the driving motor 13. There are a number of holes on the motor end plate, and the rotating connection mechanism of the subsequent joint is fixed to the motor end plate.

[0021] Three independent motor mounting cavities are provided inside the base 4. One swinging drive motor 13 is vertically installed in each mounting cavity. The three swinging drive motors 13 are circumferentially spaced around the center of the base 4 and are installed independently to ensure that the swinging movements of each finger do not interfere with each other.

[0022] As shown in Figure 7 shown, vertical motor mounting holes 11 are provided on the base 4 for the vertical installation of the driving motor. There are also openings for motor installation above it. The motor power shaft is vertically installed in the openings. There are also hole positions for installing the robotic arm at the bottom, enabling the whole dexterous hand to be installed at the end of the robotic arm as an end gripper and operating in coordination with the robotic arm. The swinging drive motor 13 is vertically installed inside the base 4, and its output shaft extends upward and is fixedly connected to a rotating frame 12.

[0023] The rotating frame 12 is an "L" - shaped structure or a connecting rod with an offset structure. The distance from its first end to the rotation center (motor axis center) is less than the distance from its second end to the rotation center, forming a lever amplification mechanism. In the embodiment of the present invention, the rotating frame 12 is made into a strengthened structure similar to a '匚' - shaped (as shown in Figure 5 shown). The first end (upper and lower ends) of the rotating frame 12 is fixedly connected to the motor shaft through the motor end plate 10; the second end (side surface) of the rotating frame 12 is fixedly connected to the root of the proximal finger tip 3 by screws, and the rotating connection mechanism of the proximal finger tip 3 is inclined outward. When the swinging drive motor 13 rotates, the rotating frame 12 rotates as a whole, and the swinging arc length of its second end is amplified, thereby driving the proximal finger tip 3 to achieve a swing greater than the rotation angle range of the motor itself.

[0024] As shown in Figure 2As shown, the distal phalanx 1 has multiple arrayed suction cup mounting teeth 5 machined on its fingertip surface for engaging a standard silicone negative pressure suction cup. The dorsal side of the finger has multiple air tube sockets 7, each socket communicating with an air hole at the bottom of a suction cup mounting tooth 5 via an internal independent air passage. The suction cup mounting teeth 5 have a stepped hole structure (e.g., ...). Figure 8 (As shown), this facilitates the installation and sealing of the suction cup.

[0025] The control system includes a controller (such as a microcontroller), multiple motor drivers, a negative pressure regulating valve, and a vacuum source. Each drive motor 13 is independently connected to a motor driver, and its position and speed are controlled in a closed-loop manner by the controller. The air tubes leading from the air tube sockets 7 of all fingers are combined and connected to the outlet of the negative pressure regulating valve, while the inlet of the valve is connected to the vacuum source. The controller can preset the optimal negative pressure value for different fabric materials, or dynamically adjust the opening of the negative pressure regulating valve in real time through sensors, thereby providing a uniform and adjustable negative pressure for the suction cups of all fingers.

[0026] The fabric gripping method of this invention is described as follows: Preparation and positioning: The controller controls the proximal tip 3 of each finger to swing to the appropriate angle, so that the three fingers are evenly spread. The robotic arm drives the dexterous hand to move above the stacked fabric.

[0027] Adhesion and Adhesion: The controller independently controls the two pitch joints of each finger, so that the fingertip 1 of each finger adapts to flattening against the fabric surface. Subsequently, according to the fabric type, the controller controls the shared negative pressure regulating valve to generate corresponding negative pressure, and all suction cups simultaneously generate adhesion force, firmly adhering to the top single layer of fabric.

[0028] Separation: The robotic arm moves vertically upward, and the adsorbed single layer of fabric is lifted at the adsorption point, successfully separating from the lower layer of fabric.

[0029] Wrapping and gripping: The controller immediately coordinates the movement of all joints of the three fingers, causing them to bend and close, forming a wrapping grip on the suspended fabric from multiple directions. At this time, the suction cups continue to provide suction force to prevent slippage, and the mechanical structure provides support to prevent wobbling.

[0030] Finally, the dexterous hand can transport the gripped and stabilized fabric to the target location and release it, completing one work cycle.

[0031] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A negative pressure suction cup dexterous hand for grasping flexible materials, characterized by: The base is circumferentially uniformly distributed with three fingers, each of which comprises a distal end, a middle end and a proximal end which are sequentially hinged from distal to proximal, wherein the proximal end is hinged with the base; the distal end of each finger is provided with a driving motor at the connection between the distal end and the middle end, the connection between the middle end and the proximal end, and the connection between the proximal end and the base; the driving motor arranged between the distal end and the middle end and between the middle end and the proximal end is used to drive the corresponding joints to perform pitching rotation; The driving motor arranged between the proximal end and the base is used to drive the proximal end to perform oscillating rotation around a vertical axis; the finger pulp side of the distal end is provided with a negative pressure suction cup mounting structure; the back side of the distal end is provided with an air pipe socket which is in communication with the negative pressure suction cup mounting structure through an air passage.

2. The negative pressure suction cup dexterous hand for grabbing flexible materials according to claim 1, characterized in that: Further comprising a gas pressure adjusting system, the gas pressure adjusting system comprises: a negative pressure adjusting valve, the gas inlet of which is connected to a vacuum source; a plurality of air pipes, one end of each air pipe is respectively connected to the air pipe socket of the distal end of each finger, and the other end is collectively connected to the gas outlet of the negative pressure adjusting valve; a controller, which is signal connected with the negative pressure adjusting valve and each pitching driving motor and oscillating driving motor, is configured to independently control the movement of each joint of each finger, and control the negative pressure adjusting valve according to the material of the cloth to be grabbed to uniformly adjust the air pressure flow of all negative pressure suction cups.

3. The negative pressure suction cup dexterous hand for grabbing flexible materials according to claim 1, characterized in that: The negative pressure suction cup mounting structure is a plurality of suction cup support fixing teeth arranged in an array, which is used to detachably mount a plurality of negative pressure suction cups.

4. The negative pressure suction cup dexterous hand for grasping flexible materials of claim 1, wherein: The distal end and the middle end are each provided with a motor mounting seat for accommodating and fixing the driving motor.

5. The negative pressure suction cup dexterous hand for grasping flexible materials of claim 4, wherein: The middle end and the proximal end are each provided with a rotary connection mechanism, and the output end of the driving motor is connected with the rotary connection mechanism to transmit power.

6. The negative pressure suction cup dexterous hand for grasping flexible materials of claim 5, wherein: The output end of the driving motor is fixed with a motor end disc, and the motor end disc is fixedly connected with the rotary connection mechanism. The rotary connection mechanism is provided with a motor end disc mounting hole and a motor shaft mounting hole, which are used to realize the transmission of driving motor power.

7. The negative pressure suction cup dexterous hand for grasping flexible materials of claim 1, wherein: The proximal end and the base are further provided with a rotating frame, the first end of the rotating frame is fixedly connected with the output shaft of the driving motor which drives the proximal end to oscillate, and the second end is fixedly connected with the proximal end; the driving motor drives the rotating frame to rotate, and in turn drives the proximal end to oscillate.

8. The negative pressure suction cup dexterous hand for grasping flexible materials of claim 7, wherein: The rotating frame is a "L" shaped or offset structure connecting rod, the distance from the first end to the rotation center is less than the distance from the second end to the rotation center, so that the oscillation angle of the proximal end is greater than the rotation angle of the output shaft of the driving motor.

9. The negative pressure suction cup dexterous hand for grasping flexible materials of claim 1, wherein: The driving motors for driving the three proximal ends to oscillate are vertically and independently installed on the base and are spaced around the circumference of the base, so that the oscillation movements of each finger are independent of each other and have no mechanical interference.

10. A method of fabric gripping using the negative pressure suction cup dexterous hand for gripping flexible materials according to any one of claims 1-9, characterized in that, The method comprises the following steps: S1: independently control the joint rotation between the proximal end of each finger and the base to adjust the overall horizontal position of each finger; S2: independently control the joint rotation of the distal end and the middle end of each finger, so that the finger pulp plane of the distal end of each finger respectively adaptively fits the surface of the cloth; S3: According to the material information of the cloth to be grabbed, the air pressure flow of all negative pressure suction cups is uniformly adjusted, and the uppermost single layer of cloth is adsorbed by the negative pressure suction cup on the negative pressure suction cup mounting structure; S4: Under the action of negative pressure adsorption, the dexterous hand is lifted to separate the adsorbed single layer of cloth from the lower layer; S5: The joint movement of each finger is independently controlled, so that each finger is inwardly folded in different postures and angles, and the separated single layer of cloth is clamped in cooperation.

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