Voice coil motor eddy current resistance test bench and test method thereof

Abstract

The purpose of this invention is to provide a test bench and testing method for eddy current resistance of a voice coil motor, belonging to the field of eddy current resistance testing. It includes a base plate, a frame, a connecting plate, a reciprocating transmission mechanism, a force detection component, and a displacement detection component. The frame is fixed to the base plate, the connecting plate is fixed to the side of the base plate, the reciprocating transmission mechanism is mounted on the connecting plate, the force detection component is mounted inside the frame, one end of the force detection component is connected to the reciprocating transmission mechanism, and the other end is connected to the voice coil motor under test. The displacement detection component is mounted on the base plate opposite the frame. This invention can directly measure the eddy current resistance generated by the voice coil motor during operation, solving the problem of the lack of a dedicated measuring device in existing technologies. Through comparative testing and phase alignment processing, the eddy current resistance component can be separated relatively accurately. The test bench has a simple structure and clear testing steps, providing experimental basis for voice coil motor structure optimization and performance analysis.

Description

Technical Field

[0001] The present invention relates to a test bench and a test method, specifically an eddy current resistance test bench and a test method. Background Technology

[0002] A voice coil motor (VCO) is a special type of direct-drive linear motor characterized by its simple structure, small size, fast response, high positioning accuracy, and good thrust linearity. It is widely used in precision servo drives, micro-nano precision positioning, optical image stabilization, semiconductor processing equipment, and precision testing instruments. Its core working principle is that a energized coil in a constant magnetic field generates an induced electromagnetic force, the magnitude of which is linearly proportional to the input current applied to the coil. For a VCO, the output thrust is its core performance indicator, directly determining the motor's servo control accuracy, dynamic response performance, and operational stability.

[0003] In the actual operation of a voice coil motor, eddy current resistance is inevitably generated. This resistance directly offsets the effective output thrust of the motor, affecting the linearity of the thrust and the dynamic response characteristics, and is one of the key factors restricting the performance improvement of the voice coil motor. The principle of eddy current resistance is as follows: When the voice coil motor is working, the metal spool carrying the coil moves in a reciprocating linear motion, cutting the magnetic field lines formed by the permanent magnet, thereby generating induced eddy currents inside the metal structure of the spool. Under the action of the magnetic field, these induced eddy currents generate a reverse electromagnetic force opposite to the direction of the spool's motion. This electromagnetic force hinders the movement of the spool, which is the eddy current resistance.

[0004] Extensive research has been conducted in this field regarding eddy current resistance during the operation of voice coil motors. However, most existing research remains focused on simulation and structural optimization design of eddy current resistance, with little mention of direct, quantitative measurement techniques and dedicated testing equipment for eddy current resistance. Current technologies for verifying the optimization effect of eddy current resistance in voice coil motors can only indirectly verify it through parameters such as motor operating speed, response time, and overall thrust fluctuation. They cannot separate eddy current resistance from the resultant force of multiple types of motion resistance coupling, nor can they directly and accurately obtain the specific numerical value of eddy current resistance generated by the voice coil motor spindle under different operating speeds and conditions.

[0005] For a long time, those skilled in the art have generally believed that the eddy current resistance in the operation of voice coil motors is deeply coupled with various types of motion resistance, making it difficult to separate and accurately measure the eddy current resistance through simple mechanical structures and repeatable experimental methods. As a result, the research and development design related to the optimization of the voice coil motor shaft structure and the improvement of thrust performance has always lacked direct experimental data support. This technical problem has not been effectively solved, which seriously restricts the research and development iteration and performance optimization of high-precision, high-thrust, and high-response voice coil motors.

[0006] While there is a wealth of research on eddy current resistance generated during the operation of voice coil motors, most studies remain at the simulation and optimization stage. Measurement of eddy current resistance is rarely mentioned, and the optimization effect of eddy current resistance is mostly verified indirectly through factors such as speed and response time. There is a lack of devices for directly measuring eddy current resistance. Summary of the Invention

[0007] The purpose of this invention is to provide a test bench and test method for directly measuring eddy current resistance of a voice coil motor.

[0008] The objective of this invention is achieved as follows: This invention discloses a test bench for eddy current resistance of a voice coil motor, characterized by comprising a base plate, a frame, a connecting plate, a reciprocating transmission mechanism, a force detection component, and a displacement detection component. The frame is fixed to the base plate, the connecting plate is fixed to the side of the base plate, the reciprocating transmission mechanism is mounted on the connecting plate, the force detection component is mounted in the frame, one end of the force detection component is connected to the reciprocating transmission mechanism, the other end of the force detection component is connected to the voice coil motor under test, and the displacement detection component is mounted on the base plate opposite to the frame.

[0009] The eddy current resistance test bench for a voice coil motor of the present invention may further include: 1. The reciprocating transmission mechanism includes a drive motor, an eccentric crank, a connecting rod, and a slide rod. The drive motor is fixed on the connecting plate, and the output shaft of the drive motor is connected to the eccentric crank. One end of the connecting rod is hinged to the eccentric crank, and the other end of the connecting rod is hinged to the slide rod. The slide rod passes through the first linear bearing.

[0010] 2. The force detection component includes an S-shaped tension / compression sensor and a connecting rod. A first guide hole and a second guide hole are respectively provided at both ends of the frame. The S-shaped tension / compression sensor is located inside the frame. One end of the S-shaped tension / compression sensor passes through the first linear bearing and is connected to the slide rod. The other end of the S-shaped tension / compression sensor is connected to the connecting rod. The connecting rod passes through the second linear bearing. The free end of the connecting rod is connected to the spool of the voice coil motor to be tested. The first linear bearing is installed in the first guide hole, and the second linear bearing is installed in the second guide hole.

[0011] 3. The displacement detection component includes a laser displacement sensor and a bracket. The bracket is fixed on the base plate. The laser displacement sensor is mounted on the bracket and its position can be adjusted along the vertical direction of the bracket. A laser baffle is vertically fixed on the slide rod. The laser baffle moves synchronously with the slide rod. The reflection of the laser baffle is set relative to the detection of the laser displacement sensor.

[0012] 4. The S-type tension / compression sensor, connecting rod, and the central axis of the voice coil motor shaft under test are set in the same direction.

[0013] 5. The S-shaped tension / compression sensor and the laser displacement sensor are synchronously triggered for acquisition, and their sampling frequencies are matched.

[0014] This invention discloses a method for testing the eddy current resistance of a voice coil motor, characterized by employing the test bench as described in claim 1, and comprising the following steps: (1) Bench setup and adjustment: Fix the voice coil motor to be tested at the end of the frame, fix the spool and the connecting rod coaxially, and adjust the vertical installation position of the laser displacement sensor so that the laser spot is projected onto the reflection center of the laser baffle (5); (2) Magnetic field control test: Start the drive motor, and through the crank-connecting rod mechanism composed of the eccentric crank and the connecting rod, convert the rotational motion of the drive motor into the reciprocating linear motion of the slide rod, thereby driving the spool to perform reciprocating linear motion at a set speed; after the reciprocating motion system is running stably, the resultant force data and displacement data of the spool are collected synchronously by the S-type tension and compression sensor and the laser displacement sensor to obtain the force-displacement synchronous dataset under the magnetic field condition; (3) No magnetic field control test: Keep all test parameters such as the running speed of the drive motor and the sampling frequency of the sensor unchanged, replace the permanent magnet of the voice coil motor under test with a non-magnetic substitute of the same size, start the drive motor again, and after the operation is stable, synchronously collect the force data and displacement data under the corresponding working conditions to obtain the force-displacement synchronous dataset under the no magnetic field working conditions. (4) Eddy current resistance separation: The displacement phase of the two sets of force-displacement synchronous datasets is aligned. After alignment, the two sets of force data are subtracted to separate the eddy current resistance value of the voice coil motor under test under this motion condition.

[0015] The present invention may also include: 1. In step (4), the displacement phase alignment specifically means: using the peak point or zero crossing point of the displacement curve as a reference, matching the displacement phase of the two sets of data sets so that the two sets of displacement curves completely overlap.

[0016] 2. By adjusting the speed of the drive motor, repeat the test process from step (2) to step (4) above to obtain the eddy current resistance of the spool at different motion speeds.

[0017] The advantages of this invention are: it can directly measure the eddy current resistance generated during the operation of a voice coil motor, solving the problem of the lack of a dedicated measuring device in the prior art; through comparative testing and phase alignment processing, the eddy current resistance component can be separated relatively accurately; the test bench structure is simple and the test steps are clear, providing experimental basis for the optimization of voice coil motor structure and performance analysis. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the assembly of the reciprocating transmission mechanism and the force detection component; Figure 3 This is a schematic diagram of the installation structure of the displacement detection component; Figure 4 This is a schematic diagram showing the connection between the voice coil motor under test and the connecting rod.

[0019] The attached figures are labeled as follows: 1. Voice coil motor under test; 2. Connecting rod; 3. Frame; 4. Connecting plate; 5. Laser baffle; 6. Pin; 7. Drive motor; 8. Laser displacement sensor; 9. Bracket; 10. Base plate; 11. Eccentric crank; 12. Connecting rod; 13. Slide rod; 14. Linear bearing; 15. S-type tension / compression sensor; 16. Linear bearing; 17. Bollard. Detailed Implementation

[0020] The invention will now be described in more detail with reference to the accompanying drawings: Combination Figure 1-4 , combined Figure 1 As shown, the voice coil motor eddy current resistance test bench of the present invention includes a base plate 10, a frame 3, a reciprocating transmission mechanism, a force detection component, and a displacement detection component. The frame 3 is fixedly installed on the upper surface of the base plate 10. Two coaxially arranged guide holes are opened on the frame 3 along the horizontal central axis. Linear bearings 14 and 16 are respectively installed in the two guide holes to provide coaxial guiding support for the moving parts.

[0021] Combination Figure 2 As shown, the assembly structure of the reciprocating transmission mechanism and the force detection component is as follows: The reciprocating transmission mechanism includes a drive motor 7, an eccentric crank 11, a connecting rod 12, and a slide rod 13. The drive motor 7 is fixedly mounted on the base plate 10 via a connecting plate 4. One side of the connecting plate 4 is fixedly connected to the side wall of the frame 3, and the bottom is fixedly connected to the base plate 10 to ensure the installation stability of the drive motor 7. The output shaft of the drive motor 7 is fixedly connected to the eccentric crank 11. The eccentric end of the eccentric crank 11 is hinged to one end of the connecting rod 12 via a pin 6. The other end of the connecting rod 12 is hinged to one end of the slide rod 13. The slide rod 13 passes through the inner hole of the linear bearing 14 and can reciprocate linearly along the axial direction of the frame 3. The force detection assembly includes an S-type tension / compression sensor 15 and a connecting rod 2. One end of the S-type tension / compression sensor 15 is fixedly connected to the other end of the slide rod 13, and the other end of the S-type tension / compression sensor 15 is fixedly connected to one end of the connecting rod 2. The connecting rod 2 passes through the inner hole of the linear bearing 16. The central axes of the slide rod 13, the S-type tension / compression sensor 15, and the connecting rod 2 are arranged collinearly to ensure the coaxiality of force transmission.

[0022] Combination Figure 3As shown, the installation structure of the displacement detection assembly is as follows: The displacement detection assembly includes a laser displacement sensor 8, a bracket 9, and a laser baffle 5. The bracket 9 is fixed on the base plate 10 and located on the side of the frame 3 near the drive motor 7. The laser displacement sensor 8 is fixedly mounted on the bracket 9 and its installation position can be adjusted vertically. The detection axis of the laser displacement sensor 8 is coaxial with the central axis of the frame 3. The laser baffle 5 is vertically fixed at the end of the slide rod 13 near the drive motor 7 and moves synchronously with the slide rod 13. The reflection of the laser baffle 5 is relative to the detection of the laser displacement sensor 8, and is used to collect the displacement data of the slide rod 13 in real time. The S-shaped tension / compression sensor 15 collects data synchronously with the laser displacement sensor 8, and their sampling frequencies are matched.

[0023] Combination Figure 4 As shown, the connection structure between the voice coil motor under test and the connecting rod is as follows: the voice coil motor under test 1 is fixedly installed on the end face of the frame 3 away from the drive motor 7. The spool 17 of the voice coil motor under test 1 is coaxially fixedly connected to the free end of the connecting rod 2. After installation, the spool 17 is completely aligned with the central axis of the connecting rod 2 and the slide rod 13, ensuring that the reciprocating motion of the spool 17 is completely synchronized with the slide rod 13.

[0024] The specific process of testing the eddy current resistance of a voice coil motor using the test bench of this embodiment is as follows: First, complete the test bench assembly and adjustment: Fix the voice coil motor 1 under test to the end of the frame 3, fix the spool 17 coaxially to the connecting rod 2, adjust the vertical installation position of the laser displacement sensor 8 so that the laser spot is projected onto the reflection center of the laser baffle 5, and complete the test bench assembly and adjustment. Second, conduct a magnetic field control test: Start the drive motor 7, and through the crank-connecting rod mechanism composed of the eccentric crank 11 and the connecting rod 12, convert the rotational motion of the drive motor 7 into the reciprocating linear motion of the slide rod 13, thereby driving the spool 17 to perform reciprocating linear motion at a set speed; after the reciprocating motion system is running stably, the resultant force data and displacement data of the spool 17 are collected synchronously by the S-type tension and compression sensor 15 and the laser displacement sensor 8 to obtain the force-displacement synchronous dataset under the magnetic field condition. The third step is a no-magnetic-field control test: keeping all test parameters such as the operating speed of the drive motor 7 and the sensor sampling frequency unchanged, the permanent magnet of the voice coil motor 1 under test is replaced with a non-magnetic substitute of the same shape and size. The drive motor 7 is restarted, and after the system stabilizes, force and displacement data under the corresponding working conditions are collected synchronously to obtain the force-displacement synchronous dataset under the no-magnetic-field working condition. The fourth step is eddy current resistance separation: using the peak point or zero-crossing point of the displacement curve as a reference, the two sets of force-displacement synchronous datasets are aligned in phase so that the two sets of displacement curves completely overlap. After alignment, the force data corresponding to the same displacement position are subtracted to separate and obtain the eddy current resistance value of the voice coil motor 1 under the motion condition. The fifth step is a multi-condition test: adjusting the operating speed of the drive motor 7, the test process from the second to the fourth step is repeated to obtain the eddy current resistance values ​​of the voice coil motor 1 under the test at different motion speeds.

Claims

1. A test bench for eddy current resistance of a voice coil motor, characterized in that: It includes a base plate, a frame, a connecting plate, a reciprocating transmission mechanism, a force detection component, and a displacement detection component. The frame is fixed on the base plate, the connecting plate is fixed on the side of the base plate, the reciprocating transmission mechanism is mounted on the connecting plate, the force detection component is mounted in the frame, one end of the force detection component is connected to the reciprocating transmission mechanism, the other end of the force detection component is connected to the voice coil motor under test, and the displacement detection component is mounted on the base plate opposite to the frame.

2. The voice coil motor eddy current resistance test bench according to claim 1, characterized in that: The reciprocating transmission mechanism includes a drive motor, an eccentric crank, a connecting rod, and a slide rod. The drive motor is fixed on the connecting plate, and the output shaft of the drive motor is connected to the eccentric crank. One end of the connecting rod is hinged to the eccentric crank, and the other end of the connecting rod is hinged to the slide rod. The slide rod passes through the first linear bearing.

3. The test bench for eddy current resistance of a voice coil motor according to claim 1, characterized in that: The force detection assembly includes an S-shaped tension / compression sensor and a connecting rod. A first guide hole and a second guide hole are respectively provided at both ends of the frame. The S-shaped tension / compression sensor is located inside the frame. One end of the S-shaped tension / compression sensor passes through the first linear bearing and is connected to the slide rod. The other end of the S-shaped tension / compression sensor is connected to the connecting rod. The connecting rod passes through the second linear bearing. The free end of the connecting rod is connected to the spool of the voice coil motor under test. The first linear bearing is installed in the first guide hole, and the second linear bearing is installed in the second guide hole.

4. The test bench for eddy current resistance of a voice coil motor according to claim 1, characterized in that: The displacement detection assembly includes a laser displacement sensor and a bracket. The bracket is fixed on the base plate, the laser displacement sensor is mounted on the bracket and its position can be adjusted along the vertical direction of the bracket, and a laser baffle is vertically fixed on the slide rod. The laser baffle moves synchronously with the slide rod, and the reflection of the laser baffle is set relative to the detection of the laser displacement sensor.

5. A test bench for eddy current resistance of a voice coil motor according to claim 3, characterized in that: The S-shaped tension / compression sensor, the connecting rod, and the central axis of the voice coil motor shaft under test are arranged in a collinear manner.

6. A test bench for eddy current resistance of a voice coil motor according to claim 3, characterized in that: The S-shaped tension / compression sensor and the laser displacement sensor are synchronously triggered for data acquisition, and their sampling frequencies are matched.

7. A method for testing the eddy current resistance of a voice coil motor, characterized in that: The test bench as described in claim 1 includes the following steps: (1) Bench setup and adjustment: Fix the voice coil motor to be tested at the end of the frame, fix the spool and the connecting rod coaxially, and adjust the vertical installation position of the laser displacement sensor so that the laser spot is projected onto the reflection center of the laser baffle (5); (2) Magnetic field control test: Start the drive motor, and through the crank-connecting rod mechanism composed of the eccentric crank and the connecting rod, convert the rotational motion of the drive motor into the reciprocating linear motion of the slide rod, thereby driving the spool to perform reciprocating linear motion at a set speed; after the reciprocating motion system is running stably, the resultant force data and displacement data of the spool are collected synchronously by the S-type tension and compression sensor and the laser displacement sensor to obtain the force-displacement synchronous dataset under the magnetic field condition; (3) No magnetic field control test: Keep all test parameters such as the running speed of the drive motor and the sampling frequency of the sensor unchanged, replace the permanent magnet of the voice coil motor under test with a non-magnetic substitute of the same size, start the drive motor again, and after the operation is stable, synchronously collect the force data and displacement data under the corresponding working conditions to obtain the force-displacement synchronous dataset under the no magnetic field working conditions. (4) Eddy current resistance separation: The displacement phase of the two sets of force-displacement synchronous datasets is aligned. After alignment, the two sets of force data are subtracted to separate the eddy current resistance value of the voice coil motor under test under this motion condition.

8. The method for testing eddy current resistance of a voice coil motor according to claim 7, characterized in that: In step (4), the displacement phase alignment specifically means: using the peak point or zero crossing point of the displacement curve as a reference, matching the displacement phase of the two sets of datasets so that the two sets of displacement curves completely overlap.

9. The method for testing eddy current resistance of a voice coil motor according to claim 7, characterized in that: By adjusting the speed of the drive motor, the test process of steps (2) to (4) above is repeated to obtain the eddy current resistance of the spool at different motion speeds.

Images