Small tool control device with self-conformal machining capacity and control method thereof

Abstract

The invention discloses a small tool control device with self-conformal processing capacity and a control method thereof. The control device is characterized by comprising a ball cage type universal joint and a spring clamp. The spring clamp comprises a clamp inner shell, a clamp outer shell and a spring chuck, and a machining tool is clamped by the spring chuck. The top end of the control device is provided with a motor I, the motor I is connected with a control L plate 1, the tail end of the L plate 1 is connected with a motor II, the motor II is connected with a control L plate 2, the L plate 2 is connected with a control motor III, the control motor III is connected with a holder control end, the holder control end is matched with a rolling bearing, the rolling bearing is in close fit with the clamp inner shell, and the clamp inner shell is connected with the control device. And then the swing angle of the inner shell is controlled through the holder, many tasks for machining difficult angles are completed, the machining effect is better, and the problem that part of machining angles cannot be machined is solved.

Description

Technical Field

[0001] The present invention relates to an ultra-precision machining technology, especially an adaptive machining control technology, specifically a small tool control device with adaptive machining ability and its control method. Background Art

[0002] With the increasing demand for complex curved surfaces, personalized customization, and high-precision machining in the high-end manufacturing field, the limitations of traditional rigid tools in dynamic machining environments have become increasingly prominent. The machining of complex workpieces (such as aerospace components, medical devices, precision molds, etc.) often faces challenges such as variable material properties, non-linear machining paths, and uncontrollable environmental disturbances. Traditional numerical control machining relies on preset programs and is difficult to adapt to errors caused by deformation, vibration, or material differences in real time, easily resulting in problems such as unstable machining quality and low efficiency.

[0003] In this context, the adaptive small tool machining technology has become a research hotspot. Its core lies in enabling the tool to autonomously adjust machining parameters (such as cutting force, feed speed, attitude angle) according to the workpiece state (such as surface topography, force change) through intelligent sensing, real-time feedback, and dynamic control, thereby improving machining accuracy and adaptability. This technology integrates cutting-edge fields such as intelligent materials, multi-sensor fusion, and machine learning algorithms and is one of the key technologies for the development of intelligent manufacturing towards flexibility and adaptability.

[0004] Chinese Patent CN113211163A proposes a six-degree-of-freedom fine-tuning device based on piezoelectric ceramic drive to compensate for machining vibration through a high-frequency response mechanism; Chinese Patent CN114310104A develops a multi-axis collaborative control strategy based on particle swarm optimization to reduce cumulative errors under complex trajectories. Chinese Patent CN114230298A designs an adaptive machining platform integrating vision, force sense, and temperature sensing, supporting multi-axis linkage and on-line quality inspection. Currently, there is no corresponding adaptive machining technology in the field of small tool precision grinding and polishing. In this field, problems such as limited machining objects, the need for multiple processes to complete the single machining of complex-shaped workpieces, low machining efficiency, and inability to operate in narrow working environments often occur, and the machining requirements of high efficiency, high adaptability, and low damage cannot be met simultaneously. Summary of the Invention

[0005] The object of the present invention is to address the problem that in the precise grinding and polishing process of small tools, the lack of adaptive machining technology restricts the machining objects, requires multiple processes to complete the single machining of complex-shaped workpieces, has low machining efficiency, and cannot be operated in a narrow working environment, failing to meet the machining requirements of high efficiency, high conformability, and low damage simultaneously. A small tool control device with self-conforming machining ability and its control method are designed. The design of the control device refers to the mechanical structures of constant velocity joints, spring clamps, and pan-tilt heads, and the control method refers to the control idea of pan-tilt heads. Using the control device and control method provided by this technology, workpiece machining by the robotic arm in a complex machining environment can be achieved, the machining angle at the end of the robotic arm can be freely adjusted, the stability of the machining tool can be maintained, the machining efficiency can be improved, and the machining accuracy is good.

[0006] One of the technical solutions of the present invention is:

[0007] A small tool control device with self-conforming machining ability, including a fixing bracket 1, characterized in that: the front end of the fixing bracket 1 is tightly fixed on the robotic arm 2, one side of the fixing bracket 1 is connected with a control device 3, the control device 3 is connected with a control bracket 4, and a rolling bearing 5 is installed on the control bracket 4; a spring clamp 7 is installed in the rolling bearing 5, one end of the spring clamp 7 is used to install a machining tool, and the other end is connected with a constant velocity joint 6, and the constant velocity joint 6 is connected with the robotic arm 2.

[0008] The control device 3 includes an L-shaped rod I 21, an L-shaped rod II 22, a motor I 23, a motor II 24, and a motor III 25. One end of the L-shaped rod I 21 is connected to the output shaft of the motor I 23, and the motor I 23 is installed on the fixing bracket 1. The motor I 23 is used to control the rotation of the L-shaped rod I 21. The rear end of the L-shaped rod I 21 is installed with a motor II 24, and an L-shaped rod II 22 is installed on the output end of the motor II 24. The motor II 24 is used to control the swing of the L-shaped rod II 22; on the other end of the L-shaped rod II 22 that is not connected to the motor II 24, a motor III 25 is installed, and the control bracket 4 is installed on the output shaft of the motor II 24. The motor III 25 is used to control the attitude of the control bracket 4.

[0009] The robotic arm 2 includes a fixed end 31 and a rotating end 32. The fixed end 31 is installed on the fixing bracket 1, and the rotating end 32 is installed on the fixed end 31. The rotating end 32 driven by an external force rotates synchronously with the outer wheel through a spline connection with the outer wheel 41 shaft.

[0010] The Cardan joint 6 includes an outer wheel 41, a cage 42, a set of balls 43 and an inner wheel 44. The shaft of the outer wheel 41 is connected to the rotating end 31 of the robotic arm through a spline; the inner wheel 44 is enclosed in the outer wheel 41, and the inner wheel 44 cooperates with the outer wheel 41 through the set of balls 43. The set of balls 43 is maintained on the cage 42 in an embedded form, and the cage 42 is installed in the inner wheel 44 to prevent the balls from falling off. The shaft end of the inner wheel 44 is connected to the spring clamp 7 through a spline.

[0011] The spring clamp 7 includes a clamp inner shell 51, a clamp outer shell 52 and a spring collet 53. The clamp inner shell 51 is sleeved on the ball bearing 5 and connected to the shaft of the inner wheel 44 through a spline. The spring collet 53 is installed at the rear end of the clamp inner shell 51. The front end of the spring collet 53 is wrapped with the clamp outer shell 52. The clamp outer shell 52 is connected to the clamp inner shell 51 through a thread, and the clamp outer shell 52 controls the tightness of the spring collet 53 through a threaded connection.

[0012] The connection between the L-shaped rod I 21 and the L-shaped rod II 22 is at the same height as the axis of the outer wheel 41.

[0013] The second technical solution of the present invention is:

[0014] A control method for a small tool control device with self-adaptive machining ability, characterized by including the following steps;

[0015] Step 1: Determine the direction in which the inner wheel 44 is going to swing. According to this direction, control the motor I 23 to make the motor I 23 control the L-shaped rod I 21 to rotate to be parallel to this direction. At this time, the L-shaped rod I 21 is parallel to the outer wheel 41. At the same time, according to this direction, control the motor III 25 to make the motor II 24 control the L-shaped rod II 22 to rotate to be parallel to this direction. At this time, the L-shaped rod II 22 is parallel to the inner wheel 44;

[0016] Step 2: According to the property that the angle between the machining tool and the workpiece remains unchanged, first, it is necessary to control the angle of the inner wheel 44 in the base coordinate system to remain unchanged all the time, and then calculate the required swing angle between the inner wheel 44 and the outer wheel 41;

[0017] Step 3: After determining the swing angle between the inner wheel 44 and the outer wheel 41, according to this angle, control the motor II 24 to make the motor II 24 control the included angle between the L-shaped rod I 21 and the L-shaped rod II 22. Utilize the property that the L-shaped rod I 21 is parallel to the shaft of the outer wheel 41 and the L-shaped rod II 22 is parallel to the shaft of the inner wheel 44, so that by controlling the included angle between the L-shaped rod I 21 and the L-shaped rod II 22, the purpose of controlling the included angle between the inner wheel 44 and the outer wheel 41 is achieved;

[0018] Step 4: Start the rotating end 32 of the robotic arm and start machining.

[0019] When adjusting the angles of the inner wheel 44 and the outer wheel 41, the machining should be stopped first, then the angles should be adjusted, and then the machining can be started again.

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

[0021] 1. The small tool control device with self-adaptive machining ability can keep the machining angle at the end of the small tool unchanged. When the robotic arm end rotates around the center of the ball cage universal joint, through the pan-tilt design of the two L-shaped rods, the rotation of the two L-shaped rods can be utilized to maintain the state of the inner wheel of the universal joint while the outer wheel of the ball cage universal joint rotates, that is, the machining angle at the end of the small tool remains unchanged.

[0022] 2. The small tool control device with self-adaptive machining ability can be used in relatively difficult machining scenarios. For example, when the shape of the workpiece to be machined is complex or the machining environment is relatively narrow, the machining tool and the workpiece cannot be brought into contact by moving the robotic arm for some surfaces of the workpiece. At this time, by using the angle adjustment ability of this device, the robotic arm can complete the machining of the workpiece in a limited space.

[0023] 3. The control method of the small tool control device with self-adaptive machining ability can be used for self-correction of the machining angle. When the robotic arm end rotates, the device can detect the angle change and automatically adjust the angles of L-shaped rod I and L-shaped rod II, so that the machining tool end maintains the original machining posture. Description of the Drawings

[0024] Figure 1 is a perspective view of the overall control device of the present invention;

[0025] Figure 2 is a perspective view of the control device of the present invention;

[0026] Figure 3 is a perspective view of the ball cage universal joint of the present invention;

[0027] Figure 4 is a perspective view of the overall spring clamp of the present invention. Detailed Embodiments

[0028] The present invention will be further described below with reference to the drawings and examples.

[0029] As Figure 1 shown,

[0030] A small tool control device with self-adaptive machining ability includes a fixed frame 1. The front end of the fixed frame is tightly fixed on the robotic arm 2. One side of the fixed frame 1 is connected with a control device 3 through a hinge. The other end of the control device 3 is fitted with a control frame 4 through a hinge. A rolling bearing 5 is installed on the other side of the control frame 4; It is characterized in that it further includes:

[0031] AsFigure 3 As shown, the ball cage type universal joint 6, the upper part of the ball cage type universal joint 6 is connected to the fixed frame 1 through a spline, and the lower part of the ball cage type universal joint 6 is connected to the spring clamp 7 through a spline;

[0032] like Figure 4 As shown, a spring clamp 7, the front end of the spring clamp 7 is connected to a universal joint through a spline, the middle part of the spring clamp 7 is connected to a rolling bearing 5 through a tight fit, and the rolling bearing 5 is surrounded by a control frame 4;

[0033] The control device 3 is characterized in that: the control device 3 includes an L-shaped rod I 21, an L-shaped rod II 22, a motor I 23, a motor II 24, and a motor III 25. The front end of the L-shaped rod I 21 is connected to the fixed frame through a hinge, and the front end of the L-shaped rod I 21 is connected to the motor I 23, and the motor I 23 is used to control the rotation of the L-shaped rod I 21. The rear end of the L-shaped rod I 21 is connected to the L-shaped rod II 22 through a hinge, and the rear end of the L-shaped rod I 21 is connected to the motor II 24, and the motor II 24 is used to control the swing of the L-shaped rod II 22. The rear end of the L-shaped rod II 22 is connected to the control frame 4 through a hinge, and the rear end of the L-shaped rod II 22 is connected to the motor III 25, and the motor III 25 is used to control the posture of the control frame 4.

[0034] The mechanical arm is characterized in that: the mechanical arm comprises a fixed end 31 and a rotating end 32, the side end of the fixed end 31 is tightly matched with a fixing frame, the lower end of the fixed end 31 wraps the rotating end 32 in a non-contact form, and the rotating end 32 is connected to the outer wheel 41 through a spline;

[0035] The ball cage universal joint 6 is characterized in that: the ball cage universal joint 6 comprises an outer wheel 41, a cage 42, a ball group 43, and an inner wheel 44. The front end of the outer wheel 41 is connected to the rotating part of the robot arm through a spline, the rear end of the outer wheel 41 is wrapped with the inner wheel 44, the front end of the inner wheel 44 is matched with the front end of the outer wheel 41 through the ball group 43, the ball group 43 is maintained on the cage 42 in an embedded form, the cage 42 is used to prevent the balls from falling off, and the rear end of the inner wheel 44 is connected to the spring clamp 7 through a spline;

[0036] The spring clamp 7 is characterized in that: the spring clamp 7 comprises a clamp inner shell 51, a clamp outer shell 52, and a spring clamp 53, the front end of the clamp inner shell 51 is connected to the inner wheel 44 through a spline, the rear end of the clamp inner shell 51 is equipped with the spring clamp 7, the front end of the spring clamp 7 is wrapped with a clamp outer shell 52, the clamp outer shell 52 is connected to the clamp inner shell 51 through a thread, and the clamp outer shell 52 controls the tightness of the spring clamp 53 through a threaded connection;

[0037] The connection between the L-shaped rod I 21 and the L-shaped rod II 22 is at the same height as the axis of the outer wheel 41, and the connection between the L-shaped rod II 22 and the L-shaped rod I 21 is at the same height as the axis of the inner wheel 44.

[0038] The operation process of the present invention is as follows:

[0039] Torque power transmission process: Figure 2 The power end 32 of the robotic arm in → the outer wheel 41 of the universal shaft → the inner wheel 44 of the universal shaft → the spring clamp 51 holding the tool.

[0040] The transmission process of the control power: Take Figure 2 as an example, the motor I 23 controls the rotation between the fixed end 31 of the robotic arm and the L-shaped rod I 21; the motor II 24 controls the rotation between the L-shaped rod I 21 and the L-shaped rod II 22; the motor III 25 controls the rotation between the L-shaped rod II 22 and the control frame 4.

[0041] A control method for a small tool control device 3 with self-adaptive machining ability, characterized in that the control method includes the following steps;

[0042] Step 1: Determine the direction in which the inner wheel 44 is about to swing. According to this direction, control the motor I 23 to make the motor I 23 control the L-shaped rod I 21 to rotate parallel to this direction. At this time, the L-shaped rod I 21 is parallel to the outer wheel 41. At the same time, according to this direction, control the motor III 25 to make the motor III 25 control the L-shaped rod II 22 to rotate parallel to this direction. At this time, the L-shaped rod II 22 is parallel to the inner wheel 44;

[0043] Step 2: According to the property that the angle between the machining tool and the workpiece remains unchanged, first, it is necessary to control the angle of the inner wheel 44 in the base coordinate system to remain unchanged all the time, and then calculate the required swing angle between the inner wheel 44 and the outer wheel 41;

[0044] Step 3: After determining the swing angle between the inner wheel 44 and the outer wheel 41, control the motor II 24 according to this angle to make the motor II 24 control the included angle between the L-shaped rod I 21 and the L-shaped rod II 22. Utilize the property that the L-shaped rod I 21 is parallel to the outer wheel 41 and the L-shaped rod II 22 is parallel to the inner wheel 44, so that by controlling the included angle between the L-shaped rod I 21 and the L-shaped rod II 22, the effect of controlling the included angle between the inner wheel 44 and the outer wheel 41 is achieved;

[0045] Step 4: Start the rotating end 32 of the robotic arm and start machining;

[0046] The control method of the small tool control device 3 with self-adaptive machining ability is characterized in that when adjusting the angles of the inner wheel 44 and the outer wheel 41, machining should be stopped first, then the angles should be adjusted, and then machining should be started again.

[0047] The control device 3 and the control method of the present application are suitable for precision grinding and polishing of workpieces with complex shapes by small tools, or for precision grinding and polishing of workpieces in narrow operating environments. The following two examples will illustrate the specific application of the fixed abrasive tool of the present application:

[0048] Example 1.

[0049] When processing titanium alloy micro-turbine blades (size: 25×15×5mm), whose structure contains multi-curved flow channels, asymmetric blade crowns and 0.3mm thin-walled areas, the profile requirements are ≤0.01mm and the surface roughness Ra≤0.8μm. In traditional processing scenarios, customized micro-special fixtures are required, and frequent replacement of molds leads to low efficiency. The small tool control device and its control method with adaptive processing capabilities of this project do not need to be replaced when encountering complex surface structures. Only the angle of the mold needs to be adjusted to complete the processing. The operation method is: first calculate the angle of the mold, and through the pan-tilt design of the two L-shaped rods, the rotation of the two L-shaped rods can be used to control the swing of the universal joint, so that the processing angle of the end of the small tool can be changed;

[0050] Through the above solution, the single-piece processing cycle is shortened to 45 minutes (the traditional process requires 120 minutes), the surface contour compliance rate is 98.7%, and the thin-wall thickness deviation is controlled within ±0.015mm.

[0051] Example 2.

[0052] When completing batch processing of aluminum alloy micro sensor housings (size: 12×8×3mm) in a 6㎡ enclosed clean room, the workpiece contains a 0.5mm microhole array and a curved sealing groove, and the position accuracy is required to be ≤0.01mm. Traditional manual operation is prone to pollution and low efficiency, so the small tool control device and its control method with self-adaptive processing capabilities are adopted in this project. When the movement of the robotic arm end is limited, the robotic arm end can be kept fixed, and the spring clamp can be controlled to swing to the required processing angle through the control device to achieve high-precision automated processing in a space-constrained environment.

[0053] The unit achieves a single-piece processing cycle of 45 seconds (70% shorter than the traditional process), a micro-hole position qualification rate of 99.6%, and a workpiece surface roughness stable at Ra0.4μm.

[0054] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A small tool control device with self-adaptive machining ability, including a fixing frame (1), characterized in that: The front end of the fixing bracket (1) is tightly fixed on the robotic arm (2). One side of the fixing bracket (1) is connected with a control device (3). The control device (3) is connected with a control bracket (4), and a rolling bearing (5) is installed on the control bracket (4); a spring clamp (7) is installed in the rolling bearing (5). One end of the spring clamp (7) is used to install a processing tool, and the other end is connected with a constant velocity joint (6), and the constant velocity joint (6) is connected with the robotic arm (2).

2. The small tool control device with self-adaptive processing ability according to claim 1, characterized in that: the control device (3) includes an L-shaped rod I (21), an L-shaped rod II (22), a motor I (23), a motor II (24), and a motor III (25). One end of the L-shaped rod I (21) is connected to the output shaft of the motor I (23), and the motor I (23) is installed on the fixing bracket (1). The motor I (23) is used to control the rotation of the L-shaped rod I (21). The motor II (24) is installed at the rear end of the L-shaped rod I (21), and the L-shaped rod II (22) is installed at the output end of the motor II (24). The motor II (24) is used to control the swing of the L-shaped rod II (22); the motor III (25) is installed at the other end of the L-shaped rod II (22) that is not connected to the motor II (24). The control bracket (4) is installed on the output shaft of the motor II (24), and the motor III (25) is used to control the attitude of the control bracket (4).

3. The small tool control device with self-adaptive processing ability according to claim 1, characterized in that: the robotic arm (2) includes a fixed end (31) and a rotating end (32). The fixed end (31) is installed on the fixing bracket (1), and the rotating end (32) is installed on the fixed end (31). The rotating end (32) driven by an external force is connected to the outer wheel (41) shaft through a spline and drives the outer wheel to rotate synchronously with the rotating end.

4. The small tool control device with self-adaptive processing ability according to claim 1, characterized in that: the constant velocity joint (6) includes an outer wheel (41), a cage (42), a ball set (43), and an inner wheel (44). The outer wheel (41) shaft is connected to the rotating end (31) of the robotic arm through a spline; the inner wheel (44) is wrapped in the outer wheel (41), and the inner wheel (44) is matched with the outer wheel (41) through the ball set (43). The ball set (43) is maintained on the cage (42) in an embedded form, and the cage (42) is installed in the inner wheel (44) to prevent the balls from falling off. The shaft end of the inner wheel (44) is connected to the spring clamp (7) through a spline.

5. The small tool control device with self-adaptive machining ability according to claim 1, characterized in that: the spring clamp (7) includes a clamp inner shell (51), a clamp outer shell (52), and a spring collet (53). The clamp inner shell (51) is sleeved in a ball bearing (5) and is axially connected to the inner wheel (44) through a spline. The spring collet (53) is installed at the rear end of the clamp inner shell (51). The front end of the spring collet (53) is externally wrapped with the clamp outer shell (52). The clamp outer shell (52) is connected to the clamp inner shell (51) by a thread, and the clamp outer shell (52) controls the tightness of the spring collet (53) through a thread connection.

6. The small tool control device with self-adaptive machining ability according to claim 2, characterized in that: the connection point between the L-shaped rod 1 (21) and the L-shaped rod 2 (22) is at the same height as the axis of the outer wheel (41).

7. A control method for a small tool control device with self - conforming processing ability according to any one of claims 1 to 5, characterized in that, The control method includes the following steps; Step 1: Determine the direction in which the inner wheel (44) is about to swing. According to this direction, control the motor I (23) to make the motor I (23) control the L-shaped rod I (21) to rotate parallel to this direction. At this time, the L-shaped rod I (21) is parallel to the outer wheel (41). At the same time, according to this direction, control the motor III (25) to make the motor II (24) control the L-shaped rod II (22) to rotate parallel to this direction. At this time, the L-shaped rod II (22) is parallel to the inner wheel (44). Step 2: According to the property that the angle between the machining tool and the workpiece remains unchanged, first, it is necessary to control the angle of the inner wheel (44) in the base coordinate system to remain unchanged all the time, and then calculate the required swing angle between the inner wheel (44) and the outer wheel (41). Step 3: After determining the swing angle between the inner wheel (44) and the outer wheel (41), control the motor II (24) according to this angle to make the motor II (24) control the included angle between the L-shaped rod I (21) and the L-shaped rod II (22). Utilize the property that the L-shaped rod I (21) is parallel to the axis of the outer wheel (41) and the L-shaped rod II (22) is parallel to the axis of the inner wheel (44), so that by controlling the included angle between the L-shaped rod I (21) and the L-shaped rod II (22), the purpose of controlling the included angle between the inner wheel (44) and the outer wheel (41) is achieved. Step 4: Start the rotating end (32) of the robotic arm to start machining.

8. The control method according to claim 7, characterized in that, When adjusting the angles of the inner wheel (44) and the outer wheel (41), machining should be stopped first, then the angles should be adjusted, and then machining should be started again.

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