Multi-degree-of-freedom macro-micro composite micro-gripper

Abstract

The application discloses a multi-degree-of-freedom macro-micro compound micro-gripper equipment, and belongs to the field of micro-nano operation and precise assembly. The equipment comprises a six-axis macro-motion control module, an adapter plate, a micro-motion module, a micro-gripper and a strain gauge sensor. The macro-motion module realizes large-stroke coarse positioning, the piezoelectric nano-positioning platform is used for fine adjustment, and the flexible hinge is used for realizing motion decoupling and disturbance isolation. The micro-gripper can be disassembled and replaced through a screw, the strain gauge sensor is attached to the flexible hinge to collect force signals, and a closed loop is constructed to realize constant force clamping. The device has large-stroke and nano-positioning precision, can be suitable for various micro-devices such as chips and optical fibers, and is suitable for semiconductor narrow space micro-assembly operation.

Description

Technical Field

[0001] This invention relates to the field of micro-nano manipulation and precision assembly technology, specifically to a multi-degree-of-freedom macro-micro composite micro gripper device. Background Technology

[0002] With the rapid development of micro-nano manufacturing technology, integrated circuit packaging technology, biomedical engineering, and fiber optic communication technology, the demand for precision manipulation and assembly at the micrometer and even nanometer scale is becoming increasingly urgent. As the end-effector of a micro-operating system, the performance of microgrippers directly determines the quality and efficiency of micro-assembly. Microgripper technology has high research value and a wide range of applications in precision manufacturing, integrated circuit packaging, and semiconductor processing.

[0003] Currently, the driving methods of micro grippers mainly include piezoelectric drive, electrostatic drive, electromagnetic drive, electrothermal drive, shape memory alloy drive, and pneumatic drive. In terms of the realization of macro-micro combined motion, the existing technologies mainly include the following schemes: (1) Pure macro motion scheme: the gripper is directly mounted on a multi-degree-of-freedom electric slide. The advantages are large stroke and strong load-bearing capacity; the disadvantages are that the resolution is limited by the mechanical transmission accuracy of the lead screw / guide rail, usually only reaching the micrometer level, unable to achieve nanometer-level alignment, and there will be end-stage jitter and positioning overshoot when approaching the target position. (2) Pure micro motion scheme: the micro gripper is driven by piezoelectric ceramic and combined with flexible hinge. The resolution of this scheme can reach the nanometer level, but the free strain of piezoelectric ceramic is only 0.1%~0.15%, and the stroke after being amplified by the flexible hinge is generally only tens of micrometers, which cannot independently complete the millimeter-level large-scale transportation from the hopper to the assembly position. (3) Macro-micro combined solution: The macro-motion module and the micro-motion module are used in series. The macro-motion module is responsible for coarse positioning over a large range from millimeters to hundreds of millimeters, while the micro-motion module is responsible for fine-tuning and attitude adjustment at the nanometer level. This architecture fundamentally resolves the contradiction between large stroke and nanometer precision and is the mainstream technology direction in the current micro-clamping field.

[0004] Existing macro-micro hybrid solutions generally suffer from the following limitations: First, the connection between the micro-gripper and the micro-motion platform lacks optimized force transmission paths, and the attitude deviation of the macro-motion module and the clamping reaction force directly affect the stability of the micro-motion positioning; second, the clamping ends are mostly customized for a single purpose, requiring complete replacement when dealing with different objects such as chips, resistors and capacitors, and optical fibers, resulting in high costs and low efficiency; third, the clamping force lacks modular integrated detection, failing to provide adaptive constant force clamping and modular rapid replacement capabilities when dealing with brittle components. Therefore, there is an urgent need for a new type of multi-degree-of-freedom macro-micro hybrid micro-gripper equipment that can achieve motion decoupling and reaction force isolation between macro-motion and micro-motion, achieve multiple uses with standardized and replaceable clamping ends, and maintain a compact overall shape suitable for integration into automated production lines. Summary of the Invention

[0005] To address the shortcomings mentioned in the background art, the present invention provides a multi-degree-of-freedom macro-micro composite micro gripper device.

[0006] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows: a multi-degree-of-freedom macro-micro composite micro gripper equipment, including a base fixing plate, a six-axis macro motion control module disposed above the base fixing plate, an adapter plate, a micro-motion module, a micro gripper, and a strain gauge sensor. The output end of the six-axis macro motion control module is fixedly connected to the micro-motion module via an adapter plate. The micro gripper is detachably installed on the output end face of the micro-motion module, and the strain gauge sensor is integrated on the micro gripper.

[0007] Furthermore, the six-axis macroscopic motion control module includes an X-axis electric slide, a Y-axis electric slide, a Z-axis electric slide, an Rx electric yaw stage, an Ry electric yaw stage, and an Rz electric rotary stage. The X-axis electric slide is fixedly mounted on the base plate, the Y-axis electric slide is fixedly mounted on the moving end face of the X-axis electric slide, the Z-axis electric slide is fixedly mounted on the moving end face of the Y-axis electric slide, the Ry electric tilting stage is fixedly mounted on the moving end face of the Z-axis electric slide, the Rz electric rotary stage is fixedly mounted on the moving end face of the Ry electric tilting stage, and the Rx electric tilting stage is fixedly mounted on the moving end face of the Rz electric rotary stage. The adapter plate is fixedly installed on the output mounting surface of the Rx electric oscillating stage.

[0008] Furthermore, the micro-motion module is a one-dimensional piezoelectric nano-positioning platform; the base of the one-dimensional piezoelectric nano-positioning platform is fixedly mounted on the adapter plate, the two ends of the micro-gripper are fixed to the fixed part of the one-dimensional piezoelectric nano-positioning platform by screws, and the middle part of the micro-gripper is fixed to the moving end face of the one-dimensional piezoelectric nano-positioning platform by screws.

[0009] Furthermore, the one-dimensional piezoelectric nanopositioning platform incorporates an I-beam-shaped flexible hinge to isolate parasitic motions, non-output direction forces, and displacements generated by the six-axis macroscopic motion control module.

[0010] Furthermore, the micro gripper is a flexible hinge-type gripping structure, which realizes the gripping and releasing action of components through the elastic deformation of its own flexible hinge.

[0011] Furthermore, the strain gauge sensor is attached to the flexible hinge of the miniature gripper to detect the clamping force and clamping displacement in real time, thereby forming a closed-loop control system to achieve constant force clamping.

[0012] Furthermore, the six-axis macroscopic motion control module is installed vertically or upside down to meet the integration requirements of confined operating spaces.

[0013] Furthermore, the micro-motion module and the micro-gripper adopt a vertical installation structure, which is suitable for application scenarios with limited gripping space.

[0014] With the above structure, the present invention has the following advantages: 1. Macro-micro hierarchical architecture achieves the unification of large stroke and nanometer precision. This invention employs a two-tiered precision architecture consisting of a macro-motion module and a micro-motion module connected in series. The macro-motion module comprises an X / Y / Z electric slide table and an Rx / Ry / Rz electric tilting / rotating stage, responsible for transporting the micro-gripper from the material hopper to the vicinity of the assembly station over a large area, with a stroke of 50~300mm and a resolution of approximately 1~5μm. The micro-motion module consists of a one-dimensional piezoelectric nano-positioning platform, responsible for nanometer-level fine-tuning during the alignment stage, with a resolution ≤10nm and a closed-loop positioning accuracy ≤50nm. This two-tiered architecture, each with its own function, fundamentally resolves the contradiction that a single platform cannot simultaneously handle large strokes and nanometer-level precision.

[0015] 2. Flexible decoupling structure improves micro-motion stability The one-dimensional piezoelectric nanopositioning platform in the micro-motion module has an I-shaped crossbeam flexible hinge built in. The parasitic motion of the macro motion control module and the forces and displacements in the non-final output direction are effectively canceled by the flexible hinge, avoiding the direct transmission of macro motion disturbances to the end gripper. This helps to ensure the motion stability and nanometer-level positioning accuracy of the micro gripper.

[0016] 3. Replaceable clamping ends enable universal operation. The miniature gripper can be quickly disassembled and replaced with just three screws. It is compatible with various types of micro-components such as chips, resistors and capacitors, and optical fibers, achieving "one device for multiple uses" without the need for complete machine replacement, significantly reducing operating costs and improving work efficiency. At the same time, the overall device has a compact structure, with only an extremely thin flexible gripper and a compact piezoelectric platform at the end. The multi-degree-of-freedom electric slide can be installed vertically or upside down according to the production line layout, making it particularly suitable for micro-pickup and alignment assembly in the confined operating space of semiconductor packaging equipment.

[0017] 4. Integrated force sensing enables precise constant force clamping Strain gauge sensors are attached to the flexible hinge of the miniature gripper to detect the clamping force and the opening and closing displacement of the gripper in real time. After establishing the correspondence through simulation and actual measurement calibration, feedback signals can be provided for closed-loop control to achieve precise constant force clamping. This effectively prevents damage to brittle components due to excessive clamping force or component detachment due to insufficient clamping force. Attached Figure Description

[0018] Figure 1A schematic diagram of the structure of a multi-degree-of-freedom macro-micro composite micro gripper device. Figure 1 .

[0019] Figure 2 A schematic diagram of the structure of a multi-degree-of-freedom macro-micro composite micro gripper device. Figure 2 .

[0020] Figure 3 A schematic diagram of the structure of a multi-degree-of-freedom macro-micro composite micro gripper device. Figure 3 .

[0021] Figure 4 This is a schematic diagram of the adapter plate structure of a multi-degree-of-freedom macro-micro composite micro gripper device.

[0022] Figure 5 This is a schematic diagram of a micro gripper structure for a multi-degree-of-freedom macro-micro composite micro gripper device.

[0023] Figure 6 This is a schematic diagram of a vertical micro gripper structure for a multi-degree-of-freedom macro-micro composite micro gripper device.

[0024] Figure 7 This is a schematic diagram of different specifications of a micro gripper for a multi-degree-of-freedom macro-micro composite micro gripper device.

[0025] Figure 8 This is a schematic diagram of the motion simulation and working principle of a multi-degree-of-freedom macro-micro composite micro gripper device.

[0026] As shown in the figure: 1. Base fixing plate; 2. X-axis electric slide; 3. Z-axis electric slide; 4. Ry electric tilting stage; 5. Rz electric rotary stage; 6. Rx electric tilting stage; 7. Adapter plate; 8. Miniature gripper; 9. One-dimensional piezoelectric nanopositioning platform; 10. Y-axis electric slide; 11. Strain gauge sensor. Detailed Implementation

[0027] The present invention will now be described in further detail with reference to the accompanying drawings.

[0028] Combined with appendix Figure 1-8 Example 1: Basic Structure Scheme The multi-degree-of-freedom macro-micro composite micro gripper equipment provided in this embodiment consists of five parts: a six-axis macro motion control module, an adapter plate 7, a micro-motion module, a micro gripper 8, and a strain gauge sensor 11.

[0029] 1. Six-axis macroscopic motion control module The six-axis macro motion control module is used to achieve large-range coarse positioning with six degrees of freedom in space, including X-axis electric slide 2, Y-axis electric slide 10, Z-axis electric slide 3, Rx electric yaw stage 6, Ry electric yaw stage 4 and Rz electric rotary stage 5.

[0030] The specific assembly relationship is as follows: the X-axis electric slide 2 is fixedly installed on the base fixing plate 1; the Y-axis electric slide 10 is fixedly installed on the moving end face of the X-axis electric slide 2 and moves along the X direction with the X-axis slide; the Z-axis electric slide 3 is fixedly installed on the moving end face of the Y-axis electric slide 10 and moves along the Y direction with the Y-axis slide; the Ry electric tilting stage 4 is fixedly installed on the moving end face of the Z-axis electric slide 3 and moves along the Z direction with the Z-axis slide; the Rz electric rotary stage 5 is fixedly installed on the moving end face of the Ry electric tilting stage 4 and can rotate around the Z-axis; the Rx electric tilting stage 6 is fixedly installed on the moving end face of the Rz electric rotary stage 5 and can rotate around the Z-axis; the Rx electric tilting stage itself can deflect around the X-axis.

[0031] Through six-axis linkage, it can realize translation in three directions (X, Y, Z) and rotation in three directions (Rx, Ry, Rz), with a stroke range of 50~300mm and a motion resolution of about 1~5μm, meeting the large-scale material handling needs from the silo to the assembly station.

[0032] 2. Adapter board and micro-motion module The adapter plate 7 is fixedly installed on the output mounting surface of the Rx electric tilting stage 6, serving as a transitional connection component between the macro module and the micro module.

[0033] The micro-motion module adopts a one-dimensional piezoelectric nano-positioning platform 9, whose base is fixedly mounted on the adapter plate 7 with screws. The one-dimensional piezoelectric nano-positioning platform 9 has a built-in I-shaped beam flexible hinge and uses piezoelectric ceramic as the driving element. It can output linear displacement with nanometer-level precision, motion resolution ≤10nm, and closed-loop positioning accuracy ≤50nm.

[0034] The I-beam flexible hinge has directional selective stiffness: it has good motion transmission capability in the output direction and high stiffness in the non-output direction. It can effectively isolate the parasitic motion caused by guide rail straightness error, angular swing, etc., and the undesired displacement caused by clamping reaction force of the six-axis macro motion control module, avoid the disturbance on the macro motion side from being transmitted to the end gripper, and ensure the positioning stability in the micro motion stage.

[0035] 3. Miniature gripper The miniature gripper 8 is an integral flexible hinge gripping structure. It opens and closes the gripper through the elastic deformation of its own flexible hinge, thereby completing the gripping and release of micro-components.

[0036] The micro gripper 8 is installed as follows: the fixing screws at both ends are fixed to the fixed part of the one-dimensional piezoelectric nanopositioning platform 9, and the screws in the middle are fixed to the moving end face of the one-dimensional piezoelectric nanopositioning platform 9. When the moving end face of the one-dimensional piezoelectric nanopositioning platform 9 outputs linear displacement, it drives the middle part of the micro gripper 8 to move, causing the flexible hinge to deform and drive the two clamps to open and close synchronously.

[0037] The miniature gripper 8 is detachable and can be installed with just three screws. The gripping end can be replaced by removing only three screws, making it suitable for micro-components of different sizes and shapes.

[0038] 4. Strain gauge type force sensing unit The strain gauge sensor 11 is attached to the flexible hinge position of the miniature gripper 8. When the flexible hinge deforms, the strain gauge generates a strain signal synchronously. The magnitude of the clamping force and the opening and closing displacement of the gripper can be obtained through signal acquisition and conversion.

[0039] Before use, the equipment must be calibrated: place a standard pressure sensor at the output end of the miniature clamp, and simultaneously record the force data of the pressure sensor and the output signal of the strain gauge during the clamp's closing process to establish a correspondence between the two and complete the calibration. During actual operation, the strain gauge's detection signal is fed back to the control system in real time, forming a closed-loop control circuit to achieve constant force clamping control.

[0040] Work process: 1. Coarse positioning stage: The six-axis macro motion control module works together to drive the end micro gripper 8 from the initial position to the top of the hopper, completing the large-range coarse positioning of the component pickup position; 2. Fine-tuning stage: The one-dimensional piezoelectric nano-positioning platform 9 of the micro-motion module outputs nanometer-level displacement to precisely fine-tune the position of the micro gripper 8, so that the gripper is aligned with the component to be clamped; 3. Clamping stage: The one-dimensional piezoelectric nanopositioning platform 9 continues to output drive displacement, so that the chuck of the micro gripper 8 closes to clamp the component; during the clamping process, the strain gauge sensor 11 detects the clamping force in real time, and stabilizes the clamping force at the set value through closed-loop control to avoid damage to the component or component falling off. 4. Handling and Alignment Stage: The six-axis macro motion control module moves the clamped components to the vicinity of the assembly station, and then the micro-motion module completes the nanometer-level precise position and attitude alignment. 5. Release phase: The one-dimensional piezoelectric nanopositioning platform 9 is reverse-driven, and the chuck of the micro gripper 8 opens to release the components, completing one operation cycle.

[0041] Example 2: Piezoelectric ultrasonic motor macro-motion scheme The difference between this embodiment and Embodiment 1 is that the six-axis macroscopic motion control module is replaced with a piezoelectric ultrasonic motor drive module. The piezoelectric ultrasonic motor possesses both millimeter-level large stroke and nanometer-level positioning accuracy, further simplifying the macro-micro composite architecture. While ensuring the operating range, it improves overall positioning accuracy, making it suitable for applications with higher requirements for integration and precision.

[0042] Example 3: Vertical Installation Scheme The difference between this embodiment and Embodiment 1 is that the micro-motion module and the micro gripper 8 adopt a vertical installation structure. When the operating space is limited in the horizontal direction, the micro gripper 8 is installed vertically to reduce the horizontal space occupied by the equipment and adapt to the usage requirements of narrow gripping environments.

[0043] Example 4: Multi-specification chuck adaptation solution The difference between this embodiment and Embodiment 1 lies in the configuration of various miniature gripper ends of different specifications: including wide flat grippers for larger chips, pointed grippers for small resistors and capacitors, and curved grippers for round optical fibers. The corresponding gripper ends can be quickly replaced according to the shape, size, and material of the object being operated on, improving the equipment's versatility.

[0044] The present invention and its embodiments have been described above. This description is not restrictive, and the actual structure is not limited thereto. In conclusion, if those skilled in the art, inspired by this description, design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the scope of protection of this invention.

Claims

1. A multi-degree-of-freedom macro-micro composite micro gripper device, characterized in that, It includes a base fixing plate (1), a six-axis macro motion control module located above the base fixing plate (1), an adapter plate (7), a micro-motion module, a micro gripper (8), and a strain gauge sensor (11). The output end of the six-axis macro motion control module is fixedly connected to the micro-motion module through the adapter plate (7). The micro gripper (8) is detachably installed on the output end face of the micro-motion module. The strain gauge sensor (11) is integrated on the micro gripper (8).

2. The multi-degree-of-freedom macro-micro composite micro gripper equipment according to claim 1, characterized in that, The six-axis macro motion control module includes an X-axis electric slide (2), a Y-axis electric slide (10), a Z-axis electric slide (3), an Rx electric yaw table (6), an Ry electric yaw table (4), and an Rz electric rotary table (5). The X-axis electric slide (2) is fixedly installed on the base fixing plate (1), the Y-axis electric slide (10) is fixedly installed on the moving end face of the X-axis electric slide (2), the Z-axis electric slide (3) is fixedly installed on the moving end face of the Y-axis electric slide (10), the Ry electric yaw table (4) is fixedly installed on the moving end face of the Z-axis electric slide (3), the Rz electric rotary table (5) is fixedly installed on the moving end face of the Ry electric yaw table (4), and the Rx electric yaw table (6) is fixedly installed on the moving end face of the Rz electric rotary table (5). The adapter plate (7) is fixedly installed on the output mounting surface of the Rx electric oscillating stage (6).

3. The multi-degree-of-freedom macro-micro composite micro gripper equipment according to claim 1, characterized in that, The micro-motion module is a one-dimensional piezoelectric nano-positioning platform (9); the base of the one-dimensional piezoelectric nano-positioning platform (9) is fixedly installed on the adapter plate (7), the two ends of the micro gripper (8) are fixed to the fixed part of the one-dimensional piezoelectric nano-positioning platform (9) by screws, and the middle part of the micro gripper (8) is fixed to the moving end face of the one-dimensional piezoelectric nano-positioning platform (9) by screws.

4. The multi-degree-of-freedom macro-micro composite micro gripper equipment according to claim 3, characterized in that, The one-dimensional piezoelectric nanopositioning platform (9) has a built-in I-shaped crossbeam flexible hinge.

5. The multi-degree-of-freedom macro-micro composite micro gripper equipment according to claim 1, characterized in that, The micro gripper (8) is a flexible hinge-type gripping structure.

6. The multi-degree-of-freedom macro-micro composite micro gripper equipment according to claim 5, characterized in that, The strain gauge sensor (11) is attached to the flexible hinge of the micro gripper (8).

7. The multi-degree-of-freedom macro-micro composite micro gripper equipment according to claim 1, characterized in that, The six-axis macroscopic motion control module can be installed vertically or upside down.

8. The multi-degree-of-freedom macro-micro composite micro gripper equipment according to claim 1, characterized in that, The micro-motion module and the micro clamp (8) adopt a vertical installation structure.

Images