A bowl-shaped part inner surface detection device based on normal force control

Abstract

The application discloses a kind of bowl-shaped part inner surface detection device based on normal force control, the device includes air floating vibration isolation platform, A-axis rotary workbench, Z2-axis linear slide, C-axis rotary workbench, detection module, triangular adapter plate, digital microscope, X-axis linear slide, Y-axis linear slide, fixed seat, Z1-axis linear slide, marble table top, detection module includes probe, chuck, adapter plate, piezoelectric displacement platform, sensor support, capacitive displacement sensor, capacitor plate, flexible hinge and fixed ring.The piezoelectric displacement platform and capacitive displacement sensor are highly integrated in the measuring head execution end, which overcomes the defect that the traditional rigid probe is easy to slide and scratch the part when facing the curvature mutation;A-axis rotary workbench with centering function, C-axis rotary workbench are used to cooperate with negative pressure air suction clamping, which avoids the concentrated stress deformation caused by traditional mechanical three-jaw chuck, and eliminates the data error caused by clamping eccentricity and attitude inclination.

Description

Technical Field

[0001] This invention belongs to the field of micro-nano detection technology and relates to a device for detecting the inner surface of a part, specifically a device for detecting the inner surface of a bowl-shaped part based on normal force control. Background Technology

[0002] With the rapid development of strategic industries such as aerospace, automobile manufacturing, precision optics, and high-end medical devices, the requirements for the processing and inspection of precision curved surface parts are becoming increasingly stringent. In particular, for various bowl-shaped or hemispherical complex parts such as radar radomes and artificial joint sockets, the precise inspection of their inner surface morphology, contour accuracy, and roughness has become a key technical link to ensure the service performance and reliability of core components.

[0003] However, existing mainstream internal surface inspection technologies, such as traditional coordinate measuring machine (CMM), optical 3D scanning, and machine vision inspection, are limited by problems such as probe interference dead angle, narrow deep cavity space, internal wall reflection and shading, and low efficiency of single-point measurement. These make it difficult to achieve high-precision, blind-zone-free, and high-efficiency morphology scanning on the inner surface of bowl-shaped parts with large curvature at the same time.

[0004] Furthermore, when dealing with complex concave curved surfaces, traditional contact measurement methods lack the ability to accurately sense and adjust the normal contact force of the probe. The measuring probe is prone to lateral slippage or abnormal contact force due to sudden changes in surface curvature, resulting in distorted measurement data or even scratching the surface of precision parts. This obvious technical shortcoming in multi-axis coordinated motion control and microscopic detection force feedback adjustment further limits its applicability in high-precision in-situ detection of complex bowl-shaped curved surfaces.

[0005] Therefore, there is an urgent need to develop a bowl-shaped part inner surface inspection device that combines flexible multi-axis coordinated motion with high-precision normal force closed-loop control to overcome the technical bottleneck of non-destructive and constant force fit measurement of complex inner curved surfaces in deep cavities. This device would enable the probe to track the normal constant force and acquire accurate data throughout the entire inner wall space, thereby meeting the urgent need of high-end precision manufacturing fields for high-quality and high-consistency inspection of complex inner cavity surfaces. Summary of the Invention

[0006] This invention provides a device for detecting the inner surface of a bowl-shaped part based on normal force control. The device effectively avoids probe slippage and surface scratches during the measurement process through closed-loop control of micro-Newton level normal force, and realizes precise detection of the inner wall morphology of the deep cavity of complex bowl-shaped parts.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A device for inspecting the inner surface of a bowl-shaped part based on normal force control includes an air-bearing vibration isolation table, an A-axis rotary table, a Z2-axis linear slide, a C-axis rotary table, a detection module, a triangular adapter plate, a digital microscope, an X-axis linear slide, a Y-axis linear slide, a fixed base, a Z1-axis linear slide, and a marble tabletop, wherein:

[0009] The A-axis rotary table and marble tabletop are mounted on an air-float vibration isolation platform;

[0010] The Z2 axis linear slide is mounted on the A axis rotary table, and the C axis rotary table is mounted on the Z2 axis linear slide.

[0011] The centerline of the rotation axis of the A-axis rotary table is orthogonal to the centerline of the rotation axis of the C-axis rotary table;

[0012] The Z1 axis linear slide is mounted on the marble table, and the Y axis linear slide is mounted on the Z1 axis linear slide via a fixed seat.

[0013] The X-axis linear slide is mounted on the Y-axis linear slide.

[0014] The detection module is mounted on the end of the X-axis linear slide via a triangular adapter plate.

[0015] The digital microscope is installed on one side of the air-bearing vibration isolation table to observe the process of the probe approaching the inner surface of the bowl-shaped part and to observe the processing information in real time.

[0016] The detection module includes a probe, a clamp, an adapter plate, a piezoelectric displacement stage, a sensor bracket, a capacitive displacement sensor, a capacitor plate, a flexible hinge, and a fixing ring.

[0017] The probe is mounted at the end of a flexible hinge via a clamp;

[0018] The capacitor plates and the clamp are fixed to a flexible hinge;

[0019] The flexible hinge is fixed to the fixed ring;

[0020] The retaining ring is mounted on the adapter plate;

[0021] The capacitive displacement sensor is mounted on the adapter plate via a sensor bracket;

[0022] The adapter plate is connected to the piezoelectric displacement stage;

[0023] The piezoelectric displacement stage is mounted on the end of the X-axis linear slide via a triangular adapter plate.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] (1) The piezoelectric displacement stage and the capacitive displacement sensor are highly integrated into the probe's execution end, enabling the tungsten steel probe to have micro-nano level displacement resolution and micro-Newton level force feedback capability. From the hardware structure perspective, this completely overcomes the defects of traditional rigid probes that are prone to slippage and scratching parts when facing sudden changes in curvature.

[0026] (2) By using an A-axis rotary table and a C-axis rotary table with self-aligning function in conjunction with negative pressure air suction clamping, non-destructive, surface contact stable fixing of bowl-shaped parts is achieved. This mechanism not only avoids the concentrated stress deformation that is easily caused by traditional mechanical three-jaw chucks, but also eliminates data errors caused by clamping eccentricity and tilting from the reference point.

[0027] (3) The overall system adopts a structural layout that combines a high aspect ratio tungsten steel probe assembly with a high-precision multi-axis turntable, which allows the probe to smoothly penetrate into the interior of the bowl-shaped part. This structural design breaks through the interference limitations of traditional coordinate measuring machines and other equipment when probing the inner surface of deep cavities, and eliminates local detection blind spots. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a device for detecting the inner surface of a bowl-shaped part based on normal force control.

[0029] Figure 2 A three-dimensional structural diagram of a device for detecting the inner surface of a bowl-shaped part based on normal force control;

[0030] Figure 3 This is a structural design drawing of the inner surface cross-section measurement module;

[0031] Figure 4 A control scheme for an inner surface inspection device for a bowl-shaped part based on normal force control;

[0032] Figure 5 This is an internal surface inspection solution. Detailed Implementation

[0033] The technical solution of the present invention will be further described below with reference to the accompanying drawings, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0034] This invention provides a device for detecting the inner surface of a bowl-shaped part based on normal force control, such as... Figure 1 and Figure 2As shown, the device includes an air-bearing vibration isolation table 1, an A-axis rotary table 2, a Z2-axis linear slide table 3, a C-axis rotary table 4, a detection module 5, a triangular adapter plate 6, a digital microscope 7, an X-axis linear slide table 8, a Y-axis linear slide table 9, a fixed base 10, a Z1-axis linear slide table 11, a marble tabletop 12, and a housing 13. The entire device is mounted on the air-bearing vibration isolation table 1 and adopts a semi-enclosed design. Wherein:

[0035] The air-float vibration isolation table 1 is equipped with a housing 13, and the housing 13 contains an A-axis rotary table 2, a Z2-axis linear slide 3, a C-axis rotary table 4, a detection module 5, a triangular adapter plate 6, a digital microscope 7, an X-axis linear slide 8, a Y-axis linear slide 9, a fixed base 10, a Z1-axis linear slide 11, and a marble tabletop 12.

[0036] The A-axis rotary table 2 and the marble tabletop 12 are mounted on the air-float vibration isolation table 1;

[0037] The Z2 axis linear slide 3 is mounted on the A axis rotary table 2, and the C axis rotary table 4 is mounted on the Z2 axis linear slide 3;

[0038] The Z1 axis linear slide 11 is mounted on the marble countertop 12, and the Y axis linear slide 9 is mounted on the Z1 axis linear slide 11 via a fixing seat 10.

[0039] The X-axis linear slide 8 is mounted on the Y-axis linear slide 9;

[0040] The detection module 5 is mounted on the end of the X-axis linear slide 8 via a triangular adapter plate 6.

[0041] The digital microscope 7 is installed on one side of the air-bearing vibration isolation table 1 to observe the process of the probe approaching the inner surface of the bowl-shaped part and to observe the processing information in real time.

[0042] The A-axis rotary table 2 and the C-axis rotary table 4 are orthogonally installed rotary tables;

[0043] The X-axis linear slide 9, Y-axis linear slide 8, Z1-axis linear slide 11, and Z2-axis linear slide 3 are ball screw linear displacement stages.

[0044] like Figure 3 As shown, the detection module 5 includes a probe 14, a clamp 15, a dust cover 16, an adapter plate 17, a piezoelectric displacement stage 18, a sensor bracket 19, a capacitive displacement sensor 20, a capacitor plate 21, a flexible hinge 22, and a fixing ring 23, wherein:

[0045] The probe 14 is mounted at the end of the flexible hinge 22 via a clamp 15;

[0046] The capacitor plate 21 and the clamp 15 are fixed to the flexible hinge 22 by a threaded connection.

[0047] The flexible hinge 22 is fixed to the fixing ring 23;

[0048] The fixing ring 23 is mounted on the adapter plate 17;

[0049] The capacitive displacement sensor 20 is mounted on the adapter plate 17 via the sensor bracket 19;

[0050] The adapter plate 17 is connected to the piezoelectric displacement stage 18 by screws;

[0051] The piezoelectric displacement stage 18 is mounted at the end of the X-axis linear slide 8 via a triangular adapter plate 6;

[0052] The capacitive displacement sensor 20 is provided with a dust cover 16, which is mounted on the fixing ring 23.

[0053] The present invention installs a digital microscope 7 on one side of the device, which moves through a linear slide 11 along the Z1 axis to observe the process of the probe approaching the inner surface of the bowl-shaped part and to observe the processing information in real time.

[0054] like Figure 4 As shown, the host computer establishes communication with the CK3M high-performance motion controller via an industrial switch, centrally coordinating the six axes (X, Y, Z1, Z2, A, C) and the handwheel module to achieve high-precision spatial pose adjustment and wide-range detection trajectory tracking between the probe and complex curved surface parts. In the micro-force control section, the system constructs an independent hardware-level normal force closed-loop circuit. It relies on a high-frequency data acquisition card to acquire voltage signals in real time and connects them to the SIM960 PID controller for high-speed calculation. Subsequently, it directly commands the piezoelectric displacement stage 18 to complete micro-nano-level dynamic displacement compensation, thereby strictly ensuring constant force contact of the probe during the scanning process.

[0055] The testing process is as follows:

[0056] (1) The bowl-shaped part is mounted on the C-axis rotary stage 4. The alignment of the center of the bowl-shaped part is crucial for the detection. Coarse adjustment is performed using a digital microscope 7, followed by fine adjustment using a laser displacement sensor. Since the center lines of the A and C rotation axes are orthogonal, to simplify the alignment process, the rotation center of the microsphere and the C-axis is aligned first, and then the rotation center of the microsphere and the A-axis is aligned.

[0057] (2) After positioning the probe 14 to the test area using the digital microscope 7, the main control computer drives the Z1 axis linear slide 11 to adjust the displacement of the probe 14, so that the probe 14 contacts the workpiece and causes the flexible hinge 22 to deform under force. The system uses the capacitive sensor 20 to monitor the deformation in real time and maintains the deformation of the flexible hinge 22 constant through PID closed-loop control. At the same time, the data acquisition system synchronously records the real-time compensation displacement of the piezoelectric displacement stage 18. After computer processing, the contour height distribution characteristics of the measured surface can be retrieved.

[0058] This invention introduces a piezoelectric displacement stage 18 and a capacitive displacement sensor 20 into the traditional nanoelectromechanical system. Using the actual normal contact force between the probe 14 and the inner wall of the part as a closed-loop feedback variable, the control system performs high-frequency real-time adjustment of the micro-displacement output of the piezoelectric ceramic. This ensures that the normal contact force between the probe and the inner surface of the bowl-shaped part remains constant at the micro-Newton level throughout the entire curved surface scanning process. This effectively overcomes the shortcomings of traditional control methods based on preset trajectories or pure displacement, which cannot dynamically and adaptively compensate for sudden curvature changes and machining errors. Under the condition of constant normal force tracking, the conformal motion trajectory of the probe 14 can completely rely on and accurately reflect the real surface contour undulations during inner surface morphology detection. This completely avoids lateral slippage of the probe, local disengagement, or rigid scratches on the surface of precision parts caused by drastic fluctuations in contact force. This results in more realistic, accurate, and highly consistent 3D contour point cloud and surface morphology data. In addition, by configuring an A-axis rotary table 2 and a C-axis rotary table 4 with self-aligning function and a negative pressure air suction clamping mechanism on the detection platform, the bowl-shaped part can be stably and accurately centered and tightly clamped, which fundamentally eliminates the local detection blind zone and measurement data distortion caused by part clamping eccentricity or tilting posture, and further ensures the high efficiency and high reliability of panoramic scanning of complex deep cavity inner walls.

Claims

1. A device for detecting the inner surface of a bowl-shaped part based on normal force control, characterized in that... The device includes an air-bearing vibration isolation table, an A-axis rotary table, a Z2-axis linear slide, a C-axis rotary table, a detection module, a triangular adapter plate, a digital microscope, an X-axis linear slide, a Y-axis linear slide, a fixed base, a Z1-axis linear slide, and a marble tabletop, wherein: The A-axis rotary table and marble tabletop are mounted on an air-float vibration isolation platform; The Z2 axis linear slide is mounted on the A axis rotary table, and the C axis rotary table is mounted on the Z2 axis linear slide. The Z1 axis linear slide is mounted on the marble table, and the Y axis linear slide is mounted on the Z1 axis linear slide via a fixed seat. The X-axis linear slide is mounted on the Y-axis linear slide. The detection module is mounted on the end of the X-axis linear slide via a triangular adapter plate. The digital microscope is installed on one side of the air-bearing vibration isolation table to observe the process of the probe approaching the inner surface of the bowl-shaped part and to observe the processing information in real time. The detection module includes a probe, a clamp, an adapter plate, a piezoelectric displacement stage, a sensor bracket, a capacitive displacement sensor, a capacitor plate, a flexible hinge, and a fixing ring. The probe is mounted at the end of a flexible hinge via a clamp; The capacitor plates and the clamp are fixed to a flexible hinge; The flexible hinge is fixed to the fixed ring; The retaining ring is mounted on the adapter plate; The capacitive displacement sensor is mounted on the adapter plate via a sensor bracket; The adapter plate is connected to the piezoelectric displacement stage; The piezoelectric displacement stage is mounted on the end of the X-axis linear slide via a triangular adapter plate.

2. The bowl-shaped part inner surface detection device based on normal force control according to claim 1, characterized in that... The air-bearing vibration isolation platform is equipped with an outer shell, and the interior of the outer shell is equipped with an A-axis rotary table, a Z2-axis linear slide, a C-axis rotary table, a detection module, a triangular adapter plate, a digital microscope, an X-axis linear slide, a Y-axis linear slide, a fixed base, a Z1-axis linear slide, and a marble tabletop.

3. The bowl-shaped part inner surface detection device based on normal force control according to claim 1, characterized in that... The centerline of the rotation axis of the A-axis rotary table is orthogonal to the centerline of the rotation axis of the C-axis rotary table.

4. The bowl-shaped part inner surface detection device based on normal force control according to claim 1, characterized in that... The X-axis linear slide, Y-axis linear slide, Z1-axis linear slide, and Z2-axis linear slide are ball screw linear displacement stages.

5. The bowl-shaped part inner surface detection device based on normal force control according to claim 1, characterized in that... The probe is a tungsten carbide probe.

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