Servo motor repeated positioning precision test equipment and test method

Abstract

The invention relates to the technical field of servo motor repeated positioning testing, and discloses servo motor repeated positioning precision testing equipment which comprises a platform, and the top of the platform is provided with a repeated positioning testing assembly and a servo motor positioning assembly for installing a servo motor. One side of the repeated positioning test assembly is provided with a connecting assembly which is quickly connected with an output shaft of the servo motor, and a load assembly is arranged at the top of the platform and close to the repeated positioning test assembly; the repeated positioning test assembly comprises a test mounting rack fixedly connected to the upper surface of the platform; the test method covers no-load and load scenes, the repeated positioning precision of the servo motor is comprehensively evaluated through encoder fixed-number-of-turns driving, multi-time moving distance recording and data processing comparison, the transmission gap between the ball screw and the screw nut is calibrated through the gap elimination mechanism, the influence of a reverse gap on the positioning precision is effectively eliminated, and the accuracy of the servo motor is improved. And an accurate initial reference is provided for testing.

Description

Technical Field

[0001] This invention relates to the field of servo motor repeatability testing technology, and more specifically to a servo motor repeatability accuracy testing device and testing method. Background Technology

[0002] In the fields of industrial automation, robotics, and precision manufacturing, servo motors, as core actuators, directly determine the machining accuracy and operational stability of the entire machine. With the increasing demands for motion control precision in high-end manufacturing, such as electronic semiconductor packaging, precision machine tool processing, and aerospace component assembly, the testing requirements for the repeatability of servo motors are becoming increasingly stringent. Accurate and comprehensive precision evaluation has become a crucial step in servo motor performance verification.

[0003] Although servo motor repeatability testing technology has made some progress, it still has many limitations in practical applications: First, existing testing methods mostly focus on accuracy testing under no-load conditions, while ignoring the impact of load changes on motor positioning performance in actual operation. This leads to discrepancies between test results and actual operating conditions, making it difficult to fully reflect the motor's performance under complex operating conditions. Second, the ball screw and screw-nut combination commonly used in servo motor transmission systems is prone to backlash during long-term operation or assembly. Existing testing equipment often lacks effective backlash elimination methods. Backlash can cause positioning lag or overshoot during motor commutation, directly affecting the accuracy of the initial test reference and resulting in significant errors in the repeatability positioning accuracy assessment results. Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, the present invention provides a servo motor repeatability positioning accuracy testing device and testing method to solve the problem that the ball screw and screw nut combination commonly used in servo motor transmission systems is prone to backlash during long-term operation or assembly.

[0005] The present invention provides the following technical solution: a servo motor repeatability testing device, comprising a platform, a repeatability testing component and a servo motor positioning component for mounting the servo motor are provided on the top of the platform, a quick-connect component for the output shaft of the servo motor is provided on one side of the repeatability testing component, and a load component is provided on the top of the platform and near the repeatability testing component. The repeatability testing assembly includes a test mounting frame fixedly connected to the upper surface of the platform. Two transverse guide rails are fixedly connected to one side of the test mounting frame. A test platform is slidably mounted between the two transverse guide rails via a slide table. A ball screw is rotatably mounted inside the test mounting frame via a vertical bearing seat. The ball screw is connected to the test platform via a screw nut. A distance measuring plate is fixedly connected to one side of the test platform. A laser displacement sensor that cooperates with the distance measuring plate is fixedly connected to the end of the test mounting frame. The top of the test mounting frame is equipped with a clearance elimination mechanism to zero out the transmission clearance between the ball screw and the screw nut.

[0006] As a further embodiment of the present invention, the gap elimination mechanism includes two blocking guide rails fixedly connected to the top of the test mounting frame, a blocking plate slidably mounted between the two blocking guide rails via a slide table, a blocking arm fixedly connected to one side of the blocking plate, a blocking cylinder provided on one side of the test mounting frame to drive the blocking plate to move along the blocking guide rails, a positioning block cooperating with the blocking arm fixedly connected to the end of the test platform, a test position slot-type photoelectric switch fixedly connected inside the test mounting frame, and a test position sensing frame cooperating with the test position slot-type photoelectric switch fixedly connected to the bottom of the test platform.

[0007] As a further embodiment of the present invention, a dynamic torque sensor is fixedly connected inside the test mounting frame. One end of the dynamic torque sensor is fixed to a ball screw, and the other end of the dynamic torque sensor is fixedly connected to a connecting spindle, which is rotatably mounted to the test mounting frame.

[0008] As a further embodiment of the present invention, the connecting assembly includes a connecting end fixedly connected to the end of the connecting spindle, the end of the connecting end having a keyway that mates with the output shaft of the servo motor, a rotary position slot type photoelectric switch fixedly connected to one side of the test mounting bracket, and a rotary position sensing frame that mates with the rotary position slot type photoelectric switch fixedly connected to the outer circumference of the connecting spindle.

[0009] As a further embodiment of the present invention, the servo motor positioning assembly includes a positioning mounting bracket fixedly connected to the top of the platform. A positioning side plate is fixedly connected to one side of the positioning mounting bracket, and at least four sets of positioning pins corresponding to the mounting holes of the servo motor are fixedly connected to one side of the positioning side plate. Two adjustment guide rails are fixedly connected to the top of the positioning mounting bracket, and an adjustment slide is slidably mounted between the two adjustment guide rails via a slide table. The interior of the adjustment slide is provided with a groove that conforms to the shape of the servo motor.

[0010] As a further embodiment of the present invention, side positioning seats are fixedly connected to both sides of the adjusting slide, and a pre-positioning groove is opened on one side of the side positioning seat. At least four pre-positioning seats are fixedly connected to the top of the positioning mounting bracket, and two pre-positioning seats on the same side correspond to the pick-up and put-down position and the test position of the servo motor, respectively. A pre-positioning bead that cooperates with the pre-positioning groove is installed on one side of the pre-positioning seat, and a return spring is installed between the pre-positioning bead and the pre-positioning seat.

[0011] As a further embodiment of the present invention, a V-groove is provided on one side of the side positioning seat, and a mounting base is fixedly connected to the top of the positioning mounting bracket. A clamping rod is inserted inside the mounting base, and a clamping wheel that mates with the V-groove is rotatably mounted on the end of the clamping rod. A push-pull quick clamp for pushing and pulling the clamping rod is provided at the end of the mounting base.

[0012] As a further embodiment of the present invention, the load assembly includes a load mounting frame fixedly connected to the top of the platform. One end of the load mounting frame is mounted with a long slotted shaft via a sliding sleeve. One end of the long slotted shaft is fixedly connected to an end frame. The end frame is provided with a quick-connect mechanism for connecting to the test bench. One side of the load mounting frame is fixedly connected to a blocking frame for blocking and limiting the end frame. The other end of the load mounting frame away from the end frame is rotatably mounted with a pulley. The other end of the long slotted shaft is fixedly connected with a steel wire, and one end of the steel wire passes around the pulley, passes through the load mounting frame, and is fixedly connected to a counterweight.

[0013] As a further embodiment of the present invention, the quick-connect mechanism includes a connecting rod inserted into one side of the end frame, and a connecting cylinder that drives the connecting rod to move on the other side of the end frame. A load connecting frame is fixedly connected to one side of the test bench, and a load slot that cooperates with the connecting rod is opened on one side of the load connecting frame.

[0014] A method for testing the repeatability of a servo motor, comprising the following steps: S1: First, install the servo motor to be tested into the servo motor positioning assembly; S2: Then, the servo motor output shaft is connected to the ball screw of the repeatability test component via the connecting component; S3: Before testing, the initial position of the test bench needs to be redefined by the clearance elimination mechanism. At this time, the initial position of the test bench is to zero the transmission clearance between the ball screw and the screw nut. S4: No-load test: By starting the servo motor, the servo motor rotates and drives the ball screw nut and test table to move along the transverse guide rail. At this time, the movement dimension of the test table is recorded by the cooperation of the distance measuring plate and the laser displacement sensor. After recording, the system is reset and the specified distance is repeated. Then, the movement distance of the test table driven by the servo motor under the specified number of revolutions is compared to determine whether the repeatability of the servo motor is consistent. S5: Load test: Connect the load component to the repeatability test component, and then repeat S3 and S4 to achieve repeatability test of the servo motor under load.

[0015] The technical effects and advantages of this invention are as follows: 1. The test method of this invention covers no-load and load scenarios. Through encoder fixed-circle drive, multiple movement distance recording and data processing comparison, the repeatability of servo motor positioning accuracy is comprehensively evaluated.

[0016] 2. This invention eliminates the transmission backlash between the ball screw and the screw nut in the clearance elimination mechanism, effectively eliminating the influence of backlash on positioning accuracy and providing a precise initial benchmark for testing.

[0017] 3. This invention uses a dynamic torque sensor to monitor changes in transmission torque in real time, which not only prevents overload but also assists in dynamic clearance zeroing, ensuring that the servo motor maintains constant torque during drive and guaranteeing the stability of the testing process.

[0018] 4. The servo motor positioning component of the present invention achieves multi-directional limiting and fixing by means of positioning pin, contour groove, pre-positioning bead and clamping wheel structure, so as to avoid the motor displacement affecting the results during the test.

[0019] 5. The connecting component of the present invention uses a keyway to securely connect with the motor output shaft for force transmission, and combines a rotary position slot photoelectric switch to guide the orientation of the keyway, simplifying connection and disassembly operations.

[0020] 6. The load assembly of the present invention is connected to the test bench by a quick-connect mechanism, and a stable load is applied by a counterweight via steel wire and pulleys to simulate actual working conditions and support accuracy testing under load. Attached Figure Description

[0021] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0022] Figure 2 This is a top view of the present invention.

[0023] Figure 3 For the present invention Figure 1 An enlarged structural diagram.

[0024] Figure 4 This is a schematic diagram of the repeatability testing component structure of the present invention.

[0025] Figure 5 For the present invention Figure 4 A schematic diagram of the bottom structure.

[0026] Figure 6 This is a schematic diagram of the connection component structure of the present invention.

[0027] Figure 7 This is a schematic diagram of the servo motor positioning component of the present invention.

[0028] Figure 8 For the present invention Figure 7 A schematic diagram of its decomposed structure.

[0029] Figure 9 This is a schematic diagram of the push-pull quick clamp structure of the present invention.

[0030] Figure 10 This is a schematic diagram of the load component structure of the present invention.

[0031] The attached diagram is labeled as follows: 1. Platform; 2. Load component; 3. Repeat positioning test component; 4. Connection component; 5. Servo motor positioning component; 201. Load mounting bracket; 202. Long slotted shaft; 203. Pulley; 204. Steel wire; 205. Counterweight; 206. Stopping frame; 207. End frame; 208. Connecting rod; 209. Connecting cylinder; 301. Test mounting bracket; 302. Lateral guide rail; 303. Dynamic torque sensor; 304. Ball screw; 305. Test bench; 30501. Test position sensing frame; 30502. Test position slotted photoelectric switch; 306. Distance measuring plate; 307. Laser displacement sensor; 308. Positioning block; 309. Stopping arm; 310. Stopping guide rail; 311. Stopping plate; 312. Stopping cylinder; 313. Load connection frame; 314. Load slot; 401. Connecting end; 402. Keyway; 403. Rotary position sensing frame; 404. Rotary position slot-type photoelectric switch; 405. Connecting spindle; 501. Positioning mounting bracket; 502. Positioning side plate; 503. Positioning pin; 504. Adjusting guide rail; 505. Adjusting slide; 50501. Insert groove; 506. Side positioning seat; 507. Mounting seat; 50701. V-groove; 50702. Clamping rod; 50703. Clamping wheel; 50704. Push-pull quick clamp; 508. Pre-positioning seat; 50801. Pre-positioning groove; 50802. Pre-positioning bead. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. In addition, the forms of the various structures described in the following embodiments are merely illustrative. The present invention is not limited to the structures described in the following embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Reference Figures 1-10 The present invention provides a servo motor repeatability testing device, including a platform 1, a repeatability testing component 3 and a servo motor positioning component 5 for mounting the servo motor on the top of the platform 1, a quick-connect component 4 for the servo motor output shaft on one side of the repeatability testing component 3, and a load component 2 on the top of the platform 1 near the repeatability testing component 3. Please refer to Figures 4-5 The repeatability testing assembly 3 includes a test mounting frame 301 bolted to the upper surface of the platform 1. Two transverse guide rails 302 are bolted to one side of the test mounting frame 301. A test table 305 is slidably mounted between the two transverse guide rails 302 via a slide table. A ball screw 304 is rotatably mounted inside the test mounting frame 301 via a vertical bearing seat. The ball screw 304 is connected to the test table 305 via a screw nut. A distance measuring plate 306 is bolted to one side of the test table 305. A laser displacement sensor 307 (model: PDL-030-485) that mates with the distance measuring plate 306 is bolted to the end of the test mounting frame 301. Since the mechanical clearance between the ball screw 304 and the screw nut is mainly manifested as axial clearance, including the clearance of the screw nut structure itself, the fit clearance between the balls and the raceways, and the elastic deformation caused by axial load, this clearance will cause the screw nut to not move and the ball screw 304 to spin freely when the ball screw 304 rotates in the reverse direction, forming a reverse clearance and affecting the positioning accuracy. Therefore, the top of the test mounting bracket 301 is equipped with a clearance elimination mechanism to zero out the transmission clearance between the ball screw 304 and the screw nut.

[0034] Specifically, the steps for testing the repeatability accuracy of a servo motor are as follows: Step 1: First, install the servo motor to be tested into the servo motor positioning assembly 5; Step 2: Then, connect the servo motor output shaft to the ball screw 304 of the repeatability test assembly 3 via the connecting component 4; Step 3: Before testing, the initial position of the test bench 305 needs to be re-determined through the backlash elimination mechanism. At this time, the initial position of the test bench 305 is to zero the transmission backlash between the ball screw 304 and the screw nut. Step 4: No-load test: By starting the servo motor, the servo motor rotates and drives the ball screw nut and test platform 305 to move along the transverse guide rail 302 through the ball screw 304. At this time, the movement dimension of the test platform 305 is recorded by the cooperation of the distance measuring plate 306 and the laser displacement sensor 307. After recording, the system is reset and the specified distance is repeated. Step 5: Load test: Connect the load component 2 to the repeatability test component 3, and then repeat steps 3 and 4 to achieve the repeatability test of the servo motor under load. Test principle: An encoder is used to drive a servo motor to rotate a specified number of revolutions (e.g., 30 revolutions). The distance traveled by the servo motor driving the test bench 305 is recorded. This operation of driving the servo motor to rotate the specified number of revolutions is repeated multiple times, and the travel distance of the servo motor driving the test bench 305 is compared to determine whether they are consistent. This is used to judge the repeatability of the servo motor.

[0035] During testing, the encoder precisely records the number of rotations of the servo motor and converts it into an electrical signal, which is then transmitted to the control system. Based on the information from the encoder, the control system precisely controls the rotation of the servo motor, ensuring accurate rotation counts each time. Simultaneously, the laser displacement sensor 307 monitors the movement distance of the test bench 305 in real time and transmits the data to the data processing system. The data processing system compares and analyzes the movement distance data obtained from multiple tests. If the movement distance data from multiple tests are consistent or the error is within the allowable range, it indicates that the servo motor has high repeatability. Conversely, if the error exceeds the allowable range, it indicates a problem with the repeatability of the servo motor, requiring further debugging or repair.

[0036] Please refer to Figure 4 In this invention, the gap elimination mechanism includes two blocking guide rails 310 fixed to the top of the test mounting frame 301 by bolts. A blocking plate 311 is slidably installed between the two blocking guide rails 310 via a slide table. A blocking arm 309 is fixed to one side of the blocking plate 311 by bolts. A blocking cylinder 312 is provided on one side of the test mounting frame 301 to drive the blocking plate 311 to move along the direction of the blocking guide rails 310. A positioning block 308 that cooperates with the blocking arm 309 is fixed to the end of the test table 305 by bolts.

[0037] The test mounting bracket 301 is internally fixed with a test position slot photoelectric switch 30502 by bolts. The bottom of the test platform 305 is fixed with a test position sensing frame 30501 that cooperates with the test position slot photoelectric switch 30502 by bolts. The cooperation between the test position slot photoelectric switch 30502 and the test position sensing frame 30501 can accurately trigger the switch signal through photoelectric sensing principle when the test platform 305 moves to the designated position, providing accurate position feedback information for the test system.

[0038] A dynamic torque sensor 303 (model JN-DN2) is fixed inside the test mounting bracket 301 by bolts. One end of the dynamic torque sensor 303 is fixed to the ball screw 304, and the other end of the dynamic torque sensor 303 is fixed to the connecting spindle 405 by bolts. The connecting spindle 405 is rotatably mounted to the test mounting bracket 301.

[0039] Specifically, when the blocking cylinder 312 is activated, it will push the blocking plate 311 to move linearly along the direction of the blocking guide rail 310, thereby driving the blocking arm 309 to move synchronously to the blocking position of the positioning block 308. At this time, the ball screw 304 is driven, and the ball screw 304 drives the test table 305 to move along the transverse guide rail 302 through the screw nut. At this time, since the positioning block 308 and the blocking arm 309 form a block, the further movement of the positioning block 308 and the test table 305 will be restricted, thereby eliminating the gap and ensuring accurate positioning during the test. The dynamic torque sensor 303 plays a crucial role in eliminating the backlash. When the positioning block 308 and the blocking arm 309 form a block, it can monitor and record the torque changes generated by the ball screw 304 during transmission in real time, ensuring that the servo motor will not be overloaded when driving the ball screw 304. In addition, during the dynamic backlash elimination process, the dynamic torque sensor 303 monitors the torque fluctuations of the ball screw 304 during transmission in real time. When it detects that the torque exceeds the set threshold, the servo motor needs to maintain a constant torque to ensure that the transmission backlash between the ball screw 304 and the screw nut is zeroed.

[0040] Please refer to Figure 6 In this invention, the connecting component 4 includes a connecting end 401 fixed to the end of the connecting spindle 405 by bolts. The end of the connecting end 401 is provided with a keyway 402 that cooperates with the output shaft of the servo motor. A rotary position slot type photoelectric switch 404 is fixed to one side of the test mounting bracket 301 by bolts. A rotary position sensing bracket 403 that cooperates with the rotary position slot type photoelectric switch 404 is fixed to the outer circumference of the connecting spindle 405 by bolts.

[0041] Specifically, the connecting end 401 is tightly engaged with the output shaft of the servo motor through the keyway 402 opened at its end. This engagement not only ensures the stability of the connection, but also enables the power of the servo motor to be efficiently transmitted to the connecting spindle 405. Meanwhile, after the test is completed, the key connection part of the keyway 402 at the end of the connection end 401 always faces upward when the connection state of the connection component 4 is released, by cooperating with the rotary position slot photoelectric switch 404 and the rotary position sensing frame 403 on the outer side of the connecting spindle 405.

[0042] Please refer to Figures 7-9 In this invention, the servo motor positioning assembly 5 includes a positioning mounting bracket 501 fixed to the top of the platform 1 by bolts. A positioning side plate 502 is fixed to one side of the positioning mounting bracket 501 by bolts. At least four sets of positioning pins 503 corresponding to the mounting holes of the servo motor are fixed to one side of the positioning side plate 502 by bolts. Two adjusting guide rails 504 are fixed to the top of the positioning mounting bracket 501 by bolts. An adjusting slide block 505 is slidably installed between the two adjusting guide rails 504 via a slide table. The interior of the adjusting slide block 505 is provided with a groove 50501 that conforms to the shape of the servo motor.

[0043] In practical use, the positioning mounting bracket 501 serves as the basic support structure for the entire servo motor positioning assembly 5, and is securely fixed to the top of the platform 1 with bolts. The positioning side plate 502 is fixed to one side of the positioning mounting bracket 501, and at least four sets of positioning pins 503 corresponding to the mounting holes of the servo motor are provided on it, which can accurately block and position the servo motor, ensuring that the servo motor is in the correct position during installation.

[0044] The adjustment slide 505 has a groove 50501 inside that is contoured to the servo motor, which further fits and positions the servo motor, enhancing the accuracy of the positioning. The adjustment slide 505 between the two adjustment guide rails 504 can slide freely on the slide table, thereby placing the servo motor in the groove 50501. Then, by pushing the adjustment slide 505, the servo motor is moved and the mounting hole of the servo motor is engaged with the positioning pin 503. The initial position of the servo motor output shaft is with its key bar facing upward, so it can be directly inserted into the keyway 402 at the end of the connecting end 401.

[0045] Both sides of the adjusting slide 505 are fixed with side positioning seats 506 by bolts. A pre-positioning groove 50801 is provided on one side of each side positioning seat 506. At least four pre-positioning seats 508 are fixed to the top of the positioning mounting bracket 501 by bolts. Two pre-positioning seats 508 on the same side correspond to the pick-up / placement position and the test position of the servo motor, respectively. A pre-positioning bead 50802 that mates with the pre-positioning groove 50801 is installed on one side of each pre-positioning seat 508. A return spring is installed between the pre-positioning bead 50802 and the pre-positioning seat 508. A V-groove 50701 is provided on one side of the base 506. The top of the positioning mounting bracket 501 is fixed with a mounting base 507 by bolts. A clamping rod 50702 is inserted inside the mounting base 507. A clamping wheel 50703 that cooperates with the V-groove 50701 is rotatably mounted on the end of the clamping rod 50702. The end of the mounting base 507 is provided with a push-pull quick clamp 50704 for pushing and pulling the clamping rod 50702. The push-pull quick clamp 50704 is prior art. Those skilled in the art can set it according to actual needs. It will not be described in detail here.

[0046] Since the side positioning seat 506 is fixed on both sides of the adjusting slide 505, the pre-positioning slot 50801 opened on it cooperates with the pre-positioning bead 50802 on the pre-positioning seat 508. When the servo motor is in the pick-up / placement position or the test position, the pre-positioning bead 50802 can quickly and accurately embed into the pre-positioning slot 50801 under the action of the return spring, realizing the pre-positioning of the servo motor in different positions, which is convenient for operators to perform pre-positioning when picking up / placement and adjusting the test position; Because the V-groove 50701 on one side of the side positioning seat 506 cooperates with the clamping wheel 50703 on the mounting seat 507, when the servo motor needs to be clamped and fixed, the operator can push the clamping rod 50702 out through the push-pull quick clamp 50704, so that the clamping wheel 50703 is embedded in the V-groove 50701, thereby locking the position of the adjusting slide 505. Because the edge of the servo motor is located between the adjusting slide 505 and the positioning side plate 502, the lateral movement of the servo motor is limited and fixed; at the same time, the vertical movement of the servo motor is also limited and fixed by the engagement of the mounting hole of the servo motor and the positioning pin 503. In this way, it can be ensured that the servo motor will not be displaced during the test, ensuring the accuracy and stability of the test results.

[0047] Please see Figure 10 In this invention, the load assembly 2 includes a load mounting bracket 201 bolted to the top of the platform 1. One end of the load mounting bracket 201 is fitted with a long groove shaft 202 via a sliding sleeve (the long groove shaft 202 has a groove on its outer circumference that matches the sliding sleeve, allowing it to move along its axis within the sliding sleeve without rotating). One end of the long groove shaft 202 is bolted to an end frame 207, which contains a quick-connect mechanism for connection to the test bench 305. A blocking bracket 206 is bolted to one side of the load mounting bracket 201 to limit and restrict the movement of the end frame 207. A pulley 203 is rotatably mounted on the other end away from the end frame 207. A steel wire 204 is fixed to the other end of the long groove shaft 202 by bolts. One end of the steel wire 204 passes around the pulley 203, passes through the load mounting frame 201, and is fixed to a counterweight 205 by bolts. The quick-connect mechanism includes a connecting rod 208 inserted into one side of the end frame 207. A connecting cylinder 209 is provided on the other side of the end frame 207 to drive the connecting rod 208 to move. A load connecting frame 313 is fixed to one side of the test bench 305 by bolts. A load slot 314 that mates with the connecting rod 208 is provided on one side of the load connecting frame 313.

[0048] Specifically, when the load component 2 is required for testing, the connecting cylinder 209 is activated, driving the connecting rod 208 to move towards the load slot 314. When the connecting rod 208 is accurately inserted into the load slot 314, the end frame 207 and the test bench 305 are quickly and stably connected through the quick-connect mechanism. The mating position of the connecting rod 208 and the load slot 314 can be determined by the mating of the test position slot photoelectric switch 30502 and the test position sensing frame 30501.

[0049] At this point, the counterweight 205 transmits gravity to the end frame 207 via the steel wire 204, long groove shaft 202, and other structures, thereby applying a stable load force to the test bench 305 to simulate the load conditions experienced by the servo motor in actual working scenarios. The blocking frame 206 effectively limits the initial position of the end frame 207. The pulley 203 changes the direction of the force and reduces friction, allowing the steel wire 204 to drive the counterweight 205 more smoothly, ensuring more precise and efficient load force transmission. Therefore, this application utilizes an intelligent sensor network composed of multiple sensors to ensure the accuracy and reliability of the test results.

[0050] It should be noted that the slotted photoelectric switch used in this application can be model EE-SX671; the cylinders in this application are all power actuators that convert the pressure energy of compressed air into mechanical energy. They can be connected to external air pipes and solenoid valves and drive the piston to perform linear reciprocating motion by controlling the gas inlet and outlet. They can be used in conjunction with magnetic switches, proximity switches or photoelectric switches to achieve precise control of the cylinder piston rod extension and retraction displacement. Those skilled in the art can set it according to actual needs, which will not be elaborated here.

[0051] The present invention is used in the following steps: S1: First, place the servo motor to be tested in the slot 50501. Then, by pushing the adjusting slide 505, the servo motor is moved and the mounting hole of the servo motor is engaged with the positioning pin 503. The initial position of the servo motor output shaft is with its key bar facing upward, so it can be directly inserted into the keyway 402 opened at the end of the connecting end 401. Under the action of the return spring, the prepositioning bead 50802 can be quickly and accurately inserted into the prepositioning slot 50801 to achieve the prepositioning of the servo motor. Then, the operator can push the clamping rod 50702 out through the push-pull quick clamp 50704 to make the clamping wheel 50703 embedded in the V-groove 50701, thereby locking the position of the adjusting slide 505. S2: After the servo motor to be tested is installed and the servo motor to be tested is connected to the keyway 402 at the end of the connection end 401, the transmission clearance between the ball screw 304 and the screw nut needs to be zeroed. S3: At this time, the blocking cylinder 312 is activated to push the blocking plate 311 to move linearly along the direction of the blocking guide rail 310, thereby driving the blocking arm 309 to move synchronously to the blocking position of the positioning block 308. Then, the servo motor drives the ball screw 304, and the ball screw 304 drives the test table 305 to move along the transverse guide rail 302 through the screw nut. At this time, due to the blocking formed by the positioning block 308 and the blocking arm 309, the further movement of the positioning block 308 and the test table 305 will be restricted, thereby realizing the elimination of the gap. During the dynamic gap elimination process, the dynamic torque sensor 303 monitors the torque fluctuation of the ball screw 304 in real time. When it detects that the torque exceeds the set threshold, the servo motor needs to maintain a constant torque to ensure that the transmission gap between the ball screw 304 and the screw nut is zeroed. S4: No-load test: The blocking cylinder 312 releases the obstruction of the positioning block 308, and the encoder drives the servo motor to rotate a specified number of revolutions. At this time, the laser displacement sensor 307 measures and records the moving distance of the test platform 305 driven by the servo motor. After the first measurement and recording is completed, the test platform 305 moves in the reverse direction to reset (the test position slot photoelectric switch 30502 and the test position sensing frame 30501 work together). S5: Repeat the S3-S4 actions multiple times, that is, drive the servo motor to rotate a specified number of revolutions, and then compare the movement distance of the servo motor drive test bench 305 in multiple tests to see if they are consistent or if the error is within the allowable range, so as to judge the repeatability of the servo motor under no-load conditions. S6: Load test: The connecting cylinder 209 is started, driving the connecting rod 208 to move towards the load slot 314. When the connecting rod 208 is accurately inserted into the load slot 314, the end frame 207 and the test bench 305 are quickly and stably connected through the quick-connect mechanism. Then, the S3-S4 actions are repeated multiple times, that is, after the transmission gap between the ball screw 304 and the screw nut is zeroed, the servo motor is driven to rotate a specified number of revolutions. Then, the movement distance of the servo motor driving the test bench 305 (under load) in multiple tests is compared to see if they are consistent or if the error is within the allowable range. This is used to determine the repeatability of the servo motor under load. S7: After the no-load test and the load test are completed, the repositioning test component 3 and the load component 2 are reset. The connecting end 401 is connected to the rotating position slot type photoelectric switch 404 and the rotating position sensing frame 403 on the outer side of the connecting spindle 405 through the cooperation of the rotating position slot type photoelectric switch 404. This ensures that when the connecting component 4 is disconnected, the key connection part of the keyway 402 opened at the end of the connecting end 401 always faces upward. Then, the locking state of the push-pull quick clamp 50704 on the adjusting slide 505 is released. At this time, the adjusting slide 505 is pulled outward and the servo motor after the test is completed is taken out.

[0052] Finally, the following points should be noted: In the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection" and "linkage" should be interpreted broadly, and can be mechanical or electrical connection, or internal connection between two components, or direct connection. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationship. When the absolute position of the described object changes, the relative positional relationship may change. The electronic components and modules used in this invention can all be commonly used parts on the market that can achieve the specific functions in this case, and the specific models and sizes can be selected and adjusted according to actual needs; The accompanying drawings of the embodiments disclosed in this invention only involve structures relevant to the embodiments disclosed in this invention. Other structures can be referred to with common designs. Unless otherwise specified, the same embodiment and different embodiments of this invention can be combined with each other.

Claims

1. A servo motor repeatability test apparatus comprising a platform (1), characterised in that: The top of the platform (1) is provided with a repeated positioning test assembly (3) and a servo motor positioning assembly (5) for installing a servo motor, one side of the repeated positioning test assembly (3) is provided with a connecting assembly (4) for quick connection with the output shaft of the servo motor, and the top of the platform (1) is provided with a load assembly (2) near the repeated positioning test assembly (3). The repeated positioning test assembly (3) comprises a test mounting frame (301) fixedly connected to the upper surface of the platform (1), two lateral guide rails (302) fixedly connected to one side of the test mounting frame (301), a test table (305) slidably mounted between the two lateral guide rails (302) through a sliding table, a ball screw (304) rotatably mounted in the test mounting frame (301) through a vertical bearing seat, and a nut connected between the ball screw (304) and the test table (305), a distance measuring plate (306) fixedly connected to one side of the test table (305), and a laser displacement sensor (307) fixedly connected to the end of the test mounting frame (301) and matched with the distance measuring plate (306). The top of the test mounting frame (301) is provided with a gap elimination mechanism for zero setting of the transmission gap of the ball screw (304) and the nut.

2. The servo motor repeat positioning accuracy test device according to claim 1, characterized in that: The gap elimination mechanism comprises two blocking guide rails (310) fixedly connected to the top of the test mounting frame (301), a blocking plate (311) slidably mounted between the two blocking guide rails (310), a blocking arm (309) fixedly connected to one side of the blocking plate (311), a blocking cylinder (312) provided on one side of the test mounting frame (301) and used for driving the blocking plate (311) to move along the direction of the blocking guide rail (310), a positioning block (308) fixedly connected to the end of the test table (305) and matched with the blocking arm (309), a test position slot photoelectric switch (30502) fixedly connected to the inside of the test mounting frame (301), and a test position sensing frame (30501) fixedly connected to the bottom of the test table (305) and matched with the test position slot photoelectric switch (30502).

3. The servo motor repeat positioning accuracy test device of claim 1, wherein: The inside of the test mounting frame (301) is fixedly connected with a dynamic torque sensor (303), one end of the dynamic torque sensor (303) is fixedly connected with the ball screw (304), and the other end of the dynamic torque sensor (303) is fixedly connected with a connecting main shaft (405), and the connecting main shaft (405) is rotatably mounted with the test mounting frame (301).

4. The servo motor repeat positioning accuracy test device of claim 3, wherein: The connecting assembly (4) comprises a connecting end (401) fixedly connected to the end of the connecting main shaft (405), a key groove (402) formed in the end of the connecting end (401) and matched with the output shaft of the servo motor, a rotary position slot photoelectric switch (404) fixedly connected to one side of the test mounting frame (301), and a rotary position sensing frame (403) fixedly connected to the circumferential outer side of the connecting main shaft (405) and matched with the rotary position slot photoelectric switch (404).

5. The servo motor repeat positioning accuracy test device of claim 1, wherein: The servo motor positioning assembly (5) includes a positioning mounting frame (501) fixedly connected to the top of the platform (1), one side of the positioning mounting frame (501) is fixedly connected with a positioning side plate (502), one side of the positioning side plate (502) is fixedly connected with at least four groups of positioning pins (503) corresponding to servo motor mounting hole positions, the top of the positioning mounting frame (501) is fixedly connected with two adjusting guide rails (504), an adjusting sliding seat (505) is slidingly installed between the two adjusting guide rails (504) through a sliding table, and a recess (50501) is formed in the servo motor profile in the adjusting sliding seat (505).

6. The servo motor repeat positioning accuracy test apparatus of claim 5, wherein: Both sides of the adjusting sliding seat (505) are fixedly connected with side positioning seats (506), one side of the side positioning seat (506) is provided with a pre-positioning groove (50801), the top of the positioning mounting frame (501) is fixedly connected with at least four pre-positioning seats (508), and the two pre-positioning seats (508) located on the same side correspond to the pick-and-place position and the test position of the servo motor respectively, a pre-positioning bead (50802) matched with the pre-positioning groove (50801) is installed on one side of the pre-positioning seat (508), and the pre-positioning bead (50802) and the pre-positioning seat (508) are connected through a return spring.

7. The servo motor repeat positioning accuracy test apparatus of claim 5, wherein: One side of the side positioning seat (506) is provided with a V-shaped groove (50701), the top of the positioning mounting frame (501) is fixedly connected with a mounting seat (507), a compression rod (50702) is inserted into the mounting seat (507), a compression wheel (50703) matched with the V-shaped groove (50701) is rotatably installed at the end of the compression rod (50702), and an end of the mounting seat (507) is provided with a push-pull type quick clamp (50704) for pushing and pulling the compression rod (50702).

8. The servo motor repeat positioning accuracy test device of claim 1, wherein: The load assembly (2) includes a load mounting frame (201) fixedly connected to the top of the platform (1), a long groove shaft (202) is installed at one end of the load mounting frame (201) through a sliding sleeve, one end of the long groove shaft (202) is fixedly connected with an end frame (207), the end frame (207) is provided with a quick connection mechanism connected with the test bench (305), one side of the load mounting frame (201) is fixedly connected with a blocking frame (206) for blocking and limiting the end frame (207), the load mounting frame (201) is rotatably installed with a pulley (203) at the other end away from the end frame (207), the other end of the long groove shaft (202) is fixedly connected with a steel wire (204), one end of the steel wire (204) passes through the load mounting frame (201) around the pulley (203) and is fixedly connected with a counterweight (205).

9. The servo motor repeat positioning accuracy test apparatus of claim 8, wherein: The quick connecting mechanism comprises a connecting rod (208) inserted on one side of an end frame (207), the other side of the end frame (207) is provided with a connecting cylinder (209) for driving the connecting rod (208) to move, one side of the test table (305) is fixedly connected with a load connecting frame (313), and one side of the load connecting frame (313) is provided with a load slot (314) matched with the connecting rod (208).

10. A method for testing the repeat positioning accuracy of a servo motor, which is suitable for the servo motor repeat positioning accuracy testing device of claim 1, characterized in that, The method comprises the following steps: S1: first, install the servo motor to be tested into the servo motor positioning assembly (5); S2: then connect the servo motor output shaft with the ball screw (304) of the repeated positioning test assembly (3) through the connecting assembly (4); S3: before testing, the initial position of the test table (305) is re-determined through the gap elimination mechanism, and the initial position of the test table (305) at this time is the zero setting of the transmission gap between the ball screw (304) and the screw nut; S4: no-load test: start the servo motor, the servo motor rotates to drive the screw nut and the test table (305) to move along the transverse guide rail (302) through the ball screw (304), the moving size of the test table (305) is recorded through the cooperation of the distance measuring plate (306) and the laser displacement sensor (307) at this time, the recording is completed, the position is reset, and the specified distance is repeatedly completed, then whether the moving distances of the test table (305) driven by the servo motor under the specified number of turns are consistent is compared, so as to judge the repeated positioning accuracy of the servo motor; S5: load test: connect the load assembly (2) with the repeated positioning test assembly (3), then repeat S3 and S4, and realize the repeated positioning accuracy test of the servo motor under the load condition.

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