Constant force microgripper based on spatially reconfigurable compliant unit

Abstract

The application discloses a constant force micro clamp based on a space composite flexible unit and relates to the technical field of micro clamp, which comprises a flexible micro clamp mechanism and a rotary driving mechanism, the flexible micro clamp mechanism comprises a swing component, space curved beam mechanisms are symmetrically arranged on the two sides of the swing component, one end of the space curved beam mechanism is connected with the swing component, the other end is connected with bistable inclined beam groups, and the two bistable inclined beam groups are connected with a micro clamp main body; the rotary driving mechanism is connected with the swing component, and is used for driving the swing component to rotate so as to realize the rotation and direct motion coupling of the flexible constant force micro clamp mechanism. The composite transmission mechanism composed of the space curved beam mechanism and the bistable inclined beam group is integrated into the micro clamp, the deformation of the space curved beam mechanism is realized, the clamping action of the clamp end is realized, the strong coupling of the rotary driving and the high-precision constant force clamping motion is realized, and the constant force clamping demand of large stroke, high resolution and low cost in the precise operation system is met.

Description

Technical Field

[0001] This invention relates to the field of micro clamp technology, and in particular to a constant force micro clamp based on a spatial composite flexible unit. Background Technology

[0002] Micro-grippers are tools used to manipulate microscopic objects, typically for micro-manipulation. They can be designed as end effectors for robotic arms and used in conjunction with various multi-degree-of-freedom actuation devices. Existing technologies include constant-force grippers, which can achieve constant force output and are easily miniaturized, for example:

[0003] CN115805540A discloses a constant-force micro clamp, including a linear actuator connected to a displacement amplification mechanism, which in turn is connected to a constant-force mechanism. It uses a bridge-type displacement amplification mechanism to amplify the stroke range, but its clamp's transmission mechanism is relatively simple, essentially achieving linear-to-linear conversion within a plane, and its structure is relatively complex. CN108724147A discloses a flexible micro clamp with a constant and adjustable clamping force output, including a static clamping mechanism mounted on a base. A linear drive motor is installed within the static clamping mechanism, and the end of the linear drive motor is connected to a moving clamping mechanism. Under the action of a guiding mechanism, the moving clamp arm moves towards the static clamping mechanism to achieve clamping. Although this solution can achieve constant-force clamping, it still involves movement within a plane, which to some extent affects execution efficiency.

[0004] Meanwhile, planar structures often employ lever amplification mechanisms or composite amplification mechanisms to perform operations at the end of the clamp. The amplification ratio depends on the size of the lever power arm. The larger the amplification ratio, the longer the power arm, which in turn makes the outer diameter of the overall structure larger. This is not conducive to the miniaturization of the overall micro clamp mechanism, and it is particularly prone to limitations when working in some narrow spaces. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a constant-force micro clamp based on a spatial composite flexible unit. This micro clamp integrates a composite transmission mechanism consisting of a spatial curved beam mechanism and a bistable inclined beam group into the micro clamp. Through the deformation of the spatial curved beam mechanism, the two clamp arms simultaneously clamp towards the middle, ultimately achieving the clamping action at the end of the clamp. This achieves strong coupling between rotary drive and high-precision constant-force clamping motion, thus meeting the requirements of large stroke, high resolution, and low cost constant-force clamping in precision operating systems.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] An embodiment of the present invention provides a constant force micro-clamp based on a spatial composite flexible unit, comprising:

[0008] A flexible micro-gripper mechanism includes a swinging component, on both sides of which are symmetrically arranged spatial curved beam mechanisms. One end of each spatial curved beam mechanism is connected to the swinging component, and the other end is connected to a bistable inclined beam group. The micro-gripper body is connected between the two bistable inclined beam groups.

[0009] A rotary drive mechanism is connected to the swing component. The rotary drive mechanism is used to drive the swing component to rotate so that the flexible constant force micro clamp mechanism can achieve rotational and linear coupling.

[0010] As a further implementation, the spatial curved beam mechanism is used to provide positive stiffness, and the bistable inclined beam group is used to provide negative stiffness. The spatial curved beam mechanism and the bistable inclined beam group can provide a constant force clamping range for the micro clamp body.

[0011] As a further implementation, the spatial curved beam mechanism includes multiple flexible spatial curved beams, which are evenly distributed along the circumference of the swinging component.

[0012] As a further implementation, the flexible spatial curved beam is helical.

[0013] As a further implementation, the bistable inclined beam assembly includes multiple bistable inclined beams, with one end of each bistable inclined beam connected to a fixing part.

[0014] As a further implementation, the angle between the connection between the bistable inclined beam and the fixing part and the vertical direction is an acute angle;

[0015] The axis of the swinging component is perpendicular to the vertical direction.

[0016] As a further implementation, the bistable inclined beam assembly also includes a support frame, in which the bistable inclined beam and the fixing part are installed;

[0017] The micro clamp body is fixedly connected to the support frame.

[0018] As a further implementation, the rotary drive mechanism includes a servo motor connected to the center of the swing component.

[0019] As a further implementation, the rotary drive mechanism also includes a swing arm connected to a servo motor, and the swing component has a swing arm groove adapted to the swing arm.

[0020] As a further implementation, the micro clamp body includes two clamp arms, with a jaw formed between the two clamp arms.

[0021] The beneficial effects of this invention are as follows:

[0022] (1) The present invention integrates a bistable inclined beam group with linear negative stiffness characteristics and a spatial curved beam mechanism with torsional positive stiffness characteristics in parallel to achieve the quasi-zero stiffness characteristics of the flexible micro clamp; the spatial curved beam mechanism realizes the conversion between rotational motion and clamping action, thereby meeting the different requirements of high-precision motion and constant force clamping in precision operation; the bistable inclined beam group directly connected to the fixed parts on both sides will output negative stiffness displacement when the clamping arm clamps, ultimately achieving the effect of zero stiffness constant force actuation;

[0023] Meanwhile, the invention has a simple structure, is easy to process and manufacture, and has high efficiency in action execution; the invention realizes the clamping action of the micro mechanism through a non-planar transmission mechanism, and designs the micro clamp transmission mechanism from the perspective of three-dimensional spatial configuration, thus expanding the application range of clamps.

[0024] (2) The transmission ratio of the input rotation angle and the clamp displacement of the constant force micro clamp of the present invention can be adjusted by changing the size parameters of the flexible spatial curved beam; by increasing the number of flexible spatial curved beams, the over-constraint effect can be increased, thereby suppressing parasitic motion in non-functional directions and achieving the goal of improving the accuracy of the micro clamp. Attached Figure Description

[0025] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0026] Figure 1 This is a perspective view of the constant force micro clamp according to one or more embodiments of the present invention;

[0027] Figure 2 This is a front view of the constant force micro clamp according to one or more embodiments of the present invention;

[0028] Figure 3 This is a side view of a constant force micro clamp according to one or more embodiments of the present invention;

[0029] Figure 4 This is an exploded view of the constant force micro clamp according to one or more embodiments of the present invention;

[0030] Figure 5 This is an assembly diagram of the constant force micro clamp according to one or more embodiments of the present invention;

[0031] Figure 6 This is a schematic diagram of the rotary drive mechanism structure according to one or more embodiments of the present invention;

[0032] Figure 7 This is a schematic diagram of the composite zero stiffness principle;

[0033] Figure 8This is a schematic diagram of the finite element deformation analysis of the constant force micro clamp according to one or more embodiments of the present invention.

[0034] Among them, 1-flexible micro-clamping mechanism, 101-flexible spatial curved beam, 102-bistable inclined beam, 103-fixed part, 104-jaw, 105-swing arm groove, 106-swing component; 2-rotational drive mechanism, 201-swing arm, 202-servo motor. Detailed Implementation

[0035] Example 1:

[0036] In a typical embodiment of the present invention, such as Figures 1-5 As shown, a constant force micro clamp based on a spatial composite flexible unit is presented.

[0037] Since the constant force micro clamps in the prior art are usually planar transmission mechanisms, their transmission accuracy is limited, resulting in insufficient execution efficiency. Based on this, this embodiment provides a constant force micro clamp based on a spatial composite flexible unit. The composite transmission mechanism consisting of a spatial curved beam mechanism and a bistable inclined beam group is integrated into the clamping device. The torque is applied by the rotary drive mechanism 2 to realize the rotation of the middle swing component 106. Then, through the deformation of the spatial curved beam mechanism, the bistable inclined beam groups on both sides and the clamping arms are simultaneously clamped towards the middle, and finally the clamping action at the end of the clamp is realized.

[0038] This embodiment achieves the quasi-zero stiffness characteristic of the flexible micro-clamp by integrating a bistable inclined beam assembly with linear negative stiffness characteristics and a spatial curved beam mechanism with torsional positive stiffness characteristics in parallel; thereby providing high transmission accuracy through rotational-linear coupling.

[0039] The constant force micro clamp described above will now be explained in detail with reference to the accompanying drawings.

[0040] like Figures 1-5 As shown, the constant force micro clamp based on the spatial composite flexible unit includes a flexible micro clamp mechanism 1, a rotary drive mechanism 2, and a micro clamp body. The rotary drive mechanism 2 is connected to the micro clamp body through the flexible micro clamp mechanism 1, and can convert the rotational motion into linear motion, thereby realizing the clamping action of the micro clamp. Among them, the flexible micro clamp mechanism 1 adopts a composite transmission mechanism.

[0041] Specifically, the flexible micro-gripper mechanism 1 mainly includes a swing component 106, a spatial curved beam mechanism, and a bistable inclined beam group. The swing component 106 is connected to the rotary drive mechanism 2 and is used to drive other components to swing. The form of the swing component 106 can be set according to the actual application scenario. In this embodiment, the swing component 106 adopts a disk structure, and the axial direction of the swing component 106 is the horizontal direction, and the direction perpendicular to the axial direction is the vertical direction.

[0042] The rotary drive mechanism 2 includes a servo motor 202, which is connected to the swing component 106 to drive the swing component 106 to rotate. To facilitate the assembly and disassembly of the device while meeting the drive requirements, the rotary drive mechanism 2 in this embodiment also includes a swing arm 201, which is connected to the shaft of the servo motor 202. The swing component 106 has a swing arm groove 105 at its center that is adapted to the swing arm 201. The swing arm 201 and the swing arm groove 105 are inserted into each other to achieve the cooperation between them.

[0043] like Figure 6 As shown, the swing arm 201 includes a cylindrical section in the middle and straight plate sections connected to both sides of the cylindrical section, so that the swing arm 201 and the swing arm groove 105 can be locked and fixed during rotation, so that the swing component 106 rotates synchronously with the swing arm 201.

[0044] Servo motor 202 is an angle servo actuator suitable for control systems that require continuous angle changes and maintenance. Compared to piezoelectric ceramics, its cost is significantly reduced. The working principle of servo motor 202 is as follows: a receiver sends a signal to servo motor 202, which is then driven by an IC on the circuit board to start a coreless motor rotating. The power is transmitted to the swing arm 201 through a reduction gear. Simultaneously, a position detector sends back a signal to determine whether the desired position has been reached.

[0045] The swing component 106 is symmetrically equipped with spatial curved beam mechanisms on both sides of the axis, that is, there are two sets of spatial curved beam mechanisms. The spatial curved beam mechanisms are connected between the swing component 106 and the bistable inclined beam group. Each bistable inclined beam group is connected to one clamp arm of the micro clamp body. The jaws 104 are formed between the two clamp arms. The rotational motion of the swing component 106 is transmitted to the clamp arm through the spatial curved beam mechanism and the bistable inclined beam 102 in sequence, thereby realizing rotational-linear coupling.

[0046] Because the spatial curved beam mechanism has positive stiffness torsion and the bistable inclined beam group has linear negative stiffness, their parallel connection achieves the quasi-zero stiffness characteristic of the flexible microgripper. The spatial curved beam mechanism includes multiple flexible spatial curved beams 101. One end of each flexible spatial curved beam 101 is connected to the side of the swing component 106 near its edge, and they are evenly distributed along the circumference of the swing component 106 to transmit stable power. The number of flexible spatial curved beams 101 can be set according to actual clamping requirements; for example, three beams can be used. By reasonably increasing the number of flexible spatial curved beams 101, over-constraint can be achieved, further suppressing parasitic motion and thus improving the motion accuracy of the microgripper.

[0047] The flexible spatial curved beam 101 is made of a flexible material. In this embodiment, the flexible spatial curved beam 101 is helical; of course, in other embodiments, the flexible spatial curved beam 101 can also have other linear structures. By adjusting the dimensional parameters, the flexible spatial curved beam 101 can achieve coupling from large torsional angle input to micro linear displacement output.

[0048] The bistable inclined beam assembly outputs negative stiffness displacement during the clamping motion of the connected clamping arm, ultimately achieving a zero-stiffness constant force actuation effect. The bistable inclined beam assembly includes multiple bistable inclined beams 102, each bistable inclined beam 102 in each assembly is supported by a support frame and connected by a fixing part 103. For example... Figure 5 As shown, the support frame in this embodiment adopts a hollow rectangular frame, and a fixing part 103 adapted to its shape is provided at the center of the support frame. That is, the fixing part 103 is a rectangular block, and a bistable inclined beam 102 is connected between the fixing part 103 and the support frame.

[0049] Since the support frame and fixing part 103 in this embodiment are rectangular structures, bistable inclined beams 102 are connected to each side of the rectangular structure, that is, a total of four bistable inclined beams 102 are provided.

[0050] Understandably, in other embodiments, the support frame may also be of other shapes, such as an annular shape, with the inner fixing part 103 being disc-shaped, and multiple bistable inclined beams 102 being evenly distributed along the circumferential direction between the support frame and the fixing part 103.

[0051] The bistable inclined beam 102 has a certain tilt angle, combined with Figure 1 , Figure 4 and Figure 5 It can be seen that the bistable inclined beam 102 is inclined from the connection end with the fixed part 103 to the connection end with the support frame. In other words, the connection point between the bistable inclined beam 102 and the fixed part 103 is set at a certain angle with the vertical direction, and this angle is an acute angle.

[0052] The number and shape of the flexible spatial curved beams 101, as well as the number and inclination angle of the bistable inclined beams 102, need to be considered comprehensively. The two need to work together to enable the micro clamp to achieve the effect of zero stiffness constant force actuation.

[0053] It should be noted that the bistable structure can switch from one stable state to another, utilizing the principle of elastic deformation of materials. In this embodiment, since one end of the bistable inclined beam 102 is fixed to the fixing part 103 and the other end is connected to the support frame that can move along the z-axis, the support frame structure can switch from one stable position to another, which is called bistable. In the latter half of the switching process, negative stiffness characteristics will appear, which can be used to cancel the positive stiffness of the spatial helical beam, achieving the goal of overall zero stiffness, and finally achieving constant force clamping in this micro-motion process.

[0054] When a driving voltage signal is given, the servo motor 202 drives the swing component 106 through the swing arm 201, thereby driving the flexible spatial curved beams 101 and the bistable inclined beams 102 to achieve rotational-linear coupling, thus realizing... Figure 8 The clamping action of jaw 104 is shown; according to... Figure 7 The composite zero stiffness principle shown uses the flexible spatial curved beam 101 to provide positive stiffness and the bistable inclined beam group to provide negative stiffness, ultimately achieving constant force clamping operation within the equivalent range.

[0055] This embodiment adopts a spatial deflection-constant force clamping mechanism transmission scheme. The spatial curved beam mechanism realizes the conversion between rotational motion and micro clamping action, thereby meeting the different requirements of high-precision motion and constant force clamping in precision operation. It has a simple structure, is easy to process and manufacture, and has high motion execution efficiency.

[0056] In this embodiment, a relatively inexpensive servo motor 202 or other rotating motor is used as the driver to achieve axial compression and torsion of the flexible spatial curved beam 101. By changing the dimensional parameters of the flexible spatial curved beam 101, the transmission ratio between the input displacement and the output rotation angle can be adjusted to adapt to the positioning requirements in different application scenarios.

[0057] This embodiment achieves the clamping action of the micro-mechanism through a non-planar transmission mechanism, and designs the micro-clamp transmission mechanism from the perspective of three-dimensional spatial configuration, thereby expanding the application range of the clamp.

[0058] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A constant force microgripper based on spatially composite flexible unit, characterized by, The application relates to a flexible micro-gripper mechanism, which comprises a swing component, symmetrical space curved beam mechanisms arranged on both sides of the swing component, a micro-gripper main body connected between the two space curved beam mechanisms, a rotating driving mechanism connected with the swing component, and a rudder connected with the center of the swing component. The space curved beam mechanism is used for providing positive stiffness, the bistable inclined beam group is used for providing negative stiffness, and the space curved beam mechanism and the bistable inclined beam group can provide a constant force clamping range of the micro-gripper main body. The rotating driving mechanism comprises a rudder connected with the center of the swing component. The space curved beam mechanism comprises a plurality of flexible space curved beams which are uniformly distributed along the circumference of the swing component. The flexible micro-gripper mechanism can adjust the transmission ratio of input displacement and output rotation angle by changing the size parameters of the flexible space curved beams. The flexible space curved beam is in a spiral shape. The bistable inclined beam group comprises a plurality of bistable inclined beams, and one end of each bistable inclined beam is connected to a fixed part.

2. The constant force microgripper based on spatially reconfigurable compliant cell according to claim 1, wherein, The connection between the bistable inclined beam and the fixed part is an acute angle with the vertical direction.

3. The constant force microgripper based on spatially composite flexible unit according to claim 1, characterized in that, The axis direction of the swing component is perpendicular to the vertical direction.

4. The constant force microgripper based on spatially composite flexible unit according to claim 3, characterized in that, The bistable inclined beam group further comprises a support frame, and the bistable inclined beam and the fixed part are installed in the support frame. The micro-gripper main body is fixedly connected with the support frame.

5. The constant force microgripper based on spatially composite flexible unit according to claim 3, characterized in that, The rotating driving mechanism further comprises a swing arm connected with the rudder, and the swing component is provided with a swing arm groove matched with the swing arm. The micro-gripper main body comprises two gripper arms, and a clamping opening is formed between the two gripper arms.

6. The constant force microgripper based on spatially composite flexible units according to claim 1, characterized in that, ​ 7. The constant force microgripper based on spatially composite flexible units according to claim 1, characterized in that, ​

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