High-precision micro steering engine and manufacturing method thereof

Abstract

The application relates to a high-precision micro steering engine and a manufacturing method thereof, and belongs to the technical field of steering engines. The high-precision micro steering engine comprises a shell, an output end, a motor, a reduction gear set, a potentiometer, a clutch and a positioning device; the potentiometer is arranged at one end of the axial direction of a gear in the reduction gear set and is coaxially arranged with the gear; the clutch is connected between the potentiometer and the corresponding gear and is used for engaging or disconnecting the power transmission between the potentiometer and the gear; the positioning device is arranged on the shell at a position corresponding to the output end and is used for locking the output end; when the high-precision micro steering engine needs to be reversed, the positioning device first locks the output end, the clutch then disconnects the connection between the potentiometer and the corresponding gear, the motor is reversed to eliminate the back difference of the reduction gear set, and then the clutch is re-engaged and the positioning device is unlocked. The high-precision micro steering engine and the manufacturing method thereof provided by the application at least solve the problem that it is difficult to design the steering engine to be small in the related art.

Description

Technical Field

[0001] This application relates to the field of servo motor technology, and in particular to a high-precision miniature servo motor and its manufacturing method. Background Technology

[0002] Miniature servos are widely used in robotics, drones, and precision control. Their core components include a motor, a reduction gear set, an output terminal, and a potentiometer for detecting the angle of the output terminal. In existing technologies, the potentiometer is mostly located at one end of the output terminal along the axial direction and coaxially connected to it, monitoring the actual angle by rotating synchronously with the output terminal. While this axial series layout is simple, the potentiometer and its mounting structure inevitably occupy additional space in the axial direction of the output terminal, significantly increasing the overall axial length of the servo. In applications requiring integration into confined spaces (such as bionic finger joints and micro-aircraft control surfaces), this layout becomes a major bottleneck restricting the miniaturization and micro-scale design of servos.

[0003] To reduce axial dimensions, some existing technologies attempt to remove the potentiometer from the output end. For example, the potentiometer is placed on one axial end of a gear in a reduction gear set, rotating synchronously with that gear. The output angle is then indirectly calculated by detecting the rotation angle of that gear. However, reduction gear sets inherently have backlash. When the motor changes from forward to reverse rotation, the gear pair needs to "fill back" the backlash before driving the output end to rotate. During this process, if the potentiometer is fixed to the gear, it will rotate synchronously in the opposite direction with the gear. However, due to the backlash, the output end does not actually rotate, causing a deviation between the potentiometer reading and the actual output angle, severely limiting control accuracy.

[0004] Therefore, how to effectively eliminate the reading deviation problem caused by the combined backlash of potentiometer side placement and reduction gear set while realizing the miniaturization and micro-miniaturization of servo motors is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] Therefore, it is necessary to provide a high-precision miniature servo motor and its manufacturing method to address the problem that potentiometer readings are prone to deviation due to hysteresis during the miniaturization process of related servo motors.

[0006] In a first aspect, embodiments of this application provide a high-precision micro servo motor, which includes a housing, an output end, a motor, a reduction gear set, a potentiometer, a clutch, and a positioning device. The output end is rotatably supported on the housing. The motor is housed within the housing. The reduction gear set connects the motor and the output end. The potentiometer is located at one axial end of a gear in the reduction gear set and is coaxial with that gear. The clutch connects the potentiometer to the corresponding gear and is used to selectively engage or disengage the power transmission between the potentiometer and the gear. The positioning device is located on the housing at a position corresponding to the output end and is used to selectively lock the output end. When the high-precision micro servo motor needs to reverse, the positioning device first locks the output end, then the clutch disengages the connection between the potentiometer and the corresponding gear, the motor reverses to eliminate the backlash of the reduction gear set, and then the clutch re-engages, and the positioning device releases the lock.

[0007] In some embodiments, the clutch is an electromagnetic clutch, a friction clutch, or a jaw clutch; the positioning device is an electromagnetically actuated positioning device, a pneumatic positioning device, or a brake-type positioning device.

[0008] Secondly, this application also provides a manufacturing method for producing the high-precision micro servo motor provided in any of the foregoing embodiments, the manufacturing method comprising the following steps: Step S1: Install the motor inside the housing; Step S2: Install the reduction gear set inside the housing, and make its input stage drive-connected to the output shaft of the motor, and its final stage drive-connected to the output end; Step S3: Rotatably mount the output end to the housing; Step S4: Install the clutch on one axial end of a certain stage gear in the reduction gear set, and connect the driving end of the clutch to the drive shaft of that stage gear. Step S5: Install the potentiometer on the driven end of the clutch and make the potentiometer coaxial with the gear of that stage; Step S6: Install the positioning device on the housing at the position corresponding to the output end; Step S7: Electrically connect the controller to the motor, potentiometer, clutch, and positioning device; Step S8: Calibrate the hysteresis compensation parameters for the assembled servo motor.

[0009] In some embodiments, step S8 includes: under the condition that the positioning device locks the output end, controlling the clutch to disengage, driving the motor to reverse, and recording the motor shaft rotation angle Δθ required from motor start-up to the complete elimination of backlash in the reduction gear set. motor The hysteresis elimination reference value D of the servo motor is calculated according to the following formula. ref : Where, k total The total reduction ratio is from the motor shaft to the output end; n is the total number of gear pairs in the reduction gear set; J i λ is the backlash arc length of the i-th gear pair; i R is the wear coefficient of the i-th stage gear pair, ranging from 0 to 0.3, with an initial value of 0; i Let be the reduction ratio of the i-th stage gear pair; α is the temperature influence coefficient, ranging from 0.01° / ℃ to 0.05° / ℃; T amb The ambient temperature during calibration is T0; the reference temperature is 20℃; Δθ res The preset residual allowable error angle ranges from 0.05° to 0.15°.

[0010] In some embodiments, the hysteresis elimination reference value D is repeatedly measured and calculated at multiple different angular positions at the output end. ref The average value is taken as the final calibration value and stored in the controller.

[0011] In some embodiments, step S8 further includes action timing calibration: measuring the locking response time T from when the controller issues a locking command to when the positioning device fully locks the output terminal. lock And the disconnection response time T from the time the controller issues the disconnection command to the time the clutch is fully disengaged. dis And verify that both satisfy the following formula: Where γ is the reliability coefficient of the lockout response time, with a value ranging from 1.5 to 3.0; σ lock The standard deviation of the lockout response time is measured multiple times; β is the load compensation coefficient, ranging from 0.8 to 1.2; M load M is the analog load torque applied to the output during calibration; rated T is the rated output torque of the servo motor. margin This serves as a baseline safety margin, ranging from 5ms to 15ms.

[0012] In some embodiments, after installing the potentiometer on the driven end of the clutch in step S5, a zero-point calibration sub-step is further included: driving the motor to rotate the output end to the mechanical zero position, then adjusting the angle of the potentiometer to make the output value of the potentiometer zero, and finally locking the potentiometer.

[0013] In some embodiments, during the zero-point calibration sub-step, the angle of the potentiometer is adjusted by a fine-tuning fixture with a resolution of 0.1°. After locking the potentiometer, the motor is driven again to rotate the output terminal to the mechanical zero position to verify whether the output value of the potentiometer is still zero. If the deviation exceeds ±0.05°, the zero-point calibration sub-step is repeated until the requirements are met.

[0014] In some embodiments, step S6 is followed by a locking function verification step: the control positioning device locks the output end and applies 60% to 80% of the rated torque to the motor, and detects that the angle change of the output end does not exceed 0.1°.

[0015] In some embodiments, step S8 includes the following sub-steps performed sequentially: Step S81: Position the output end to the first calibration angle θ1, and then perform the following reverse simulation actions in sequence: control the positioning device to lock the output end, control the clutch to disengage, drive the motor to reverse to eliminate the backlash of the reduction gear set, control the clutch to re-engage, control the positioning device to unlock, and measure and record the first backlash compensation value B1. Step S82: Rotate the output terminal to the second calibration angle θ2, where θ2 = θ2 + 90°. Repeat step S81, measure and record the second hysteresis compensation value B2. Step S83: Compare B1 and B2. If the absolute value of the difference between the two, |B2-B1|, is greater than the preset threshold ε, then rotate the output terminal to the third calibration angle θ3=θ1+180° and the fourth calibration angle θ4=θ1+270° in sequence, and measure and record B3 and B4 respectively. Step S84: Take the average value of B1, B2, B3, and B4 as the final hysteresis compensation value and store it in the controller.

[0016] The high-precision miniature servo motor and its manufacturing method provided by the embodiments of this application have at least the following beneficial effects: By placing the potentiometer on one axial end of a gear in a reduction gear set and coaxially with that gear, the potentiometer is moved axially out of the output end. The radial space of the reduction gear set is used to accommodate the potentiometer, thereby significantly shortening the overall axial length of the servo and achieving miniaturization. By setting a clutch connecting the potentiometer and the corresponding gear, and a positioning device on the housing corresponding to the output end position, when the servo needs to reverse, the positioning device is controlled to first lock the output end and the clutch before disconnecting the connection between the potentiometer and the corresponding gear. This prevents the hysteresis eliminated by the motor reversal from being transmitted to the potentiometer. After the hysteresis is eliminated, the clutch is re-engaged and the output end is unlocked. Thus, while maintaining a compact structure, the deviation between the potentiometer reading and the actual angle at the output end caused by the hysteresis of the reduction gear set is avoided, ensuring the control accuracy of the servo.

[0017] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a three-dimensional structural diagram of a high-precision micro servo motor provided in one embodiment of this application; Figure 2 This is a three-dimensional structural diagram of a high-precision micro servo motor after removing its housing, provided in one embodiment of this application. Figure 3 This is a flowchart of a high-precision micro servo motor manufacturing method provided in one embodiment of this application.

[0020] Explanation of reference numerals in the attached diagram: 100, high-precision micro servo motor; 10, housing; 20, output terminal; 30, motor; 40, reduction gear set; 50, potentiometer; 60, clutch; 70, controller. Detailed Implementation

[0021] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0022] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0023] Furthermore, where the term "and / or" appears, "and / or" merely describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship. Where the terms "first" and "second" appear, these terms are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" can explicitly or implicitly include at least one of those features. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0024] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0025] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0026] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0027] Please refer to the following: Figure 1 and Figure 2This application provides a high-precision micro servo motor 100, which includes a housing 10, an output terminal 20, a motor 30, a reduction gear set 40, a potentiometer 50, a clutch 60, and a positioning device (not shown). The output terminal 20 is rotatably supported on the housing 10. The motor 30 is disposed within the housing 10. The reduction gear set 40 connects the motor 30 and the output terminal 20. The potentiometer 50 is disposed at one axial end of a certain stage of the reduction gear set 40 and coaxially with that stage of gear. The clutch 60 connects the potentiometer 50 to the corresponding gear, selectively engaging or disengaging the power transmission between the potentiometer 50 and the gear. The positioning device is disposed on the housing 10 at a position corresponding to the output terminal 20, selectively locking the output terminal 20. When the high-precision micro servo motor 100 needs to reverse, the positioning device first locks the output terminal 20, then the clutch 60 disengages the potentiometer 50 from the corresponding gear, the motor 30 reverses to eliminate the backlash of the reduction gear set 40, then the clutch 60 re-engages, and the positioning device releases the lock.

[0028] The high-precision micro servo motor 100 is a compact actuator that provides high-precision angle control and position holding. Compared with servo motors of related technologies, the high-precision micro servo motor 100 provided in this application changes the setting position of the potentiometer 50, transferring the potentiometer 50 from the end of the output terminal 20 of the servo motor to a certain gear of the reduction gear set 40. This provides a structural basis for the miniaturization or even micro-miniaturization design of the servo motor. At the same time, it also allows both ends of the output terminal 20 along the axial direction to be used for connection with external components (one end of the output terminal 20 of a conventional servo motor is usually used to set the potentiometer 50), increasing the applicable scenarios of the high-precision micro servo motor 100.

[0029] The embodiments of this application aim to address the problems of low repeatability and backlash or positional deviation during reversal caused by gear backlash (gear clearance) after the potentiometer 50 is transferred to be connected to the reduction gear set 40, thereby significantly improving its performance and reliability in application scenarios with stringent control accuracy requirements such as robot joints and precision gimbals.

[0030] The housing 10 is the external structural component of the high-precision miniature servo 100, used to house, support, and protect all other internal functional components, and to provide a precise mounting and positioning reference for these components. The housing 10 is typically made of metal (such as aluminum alloy) or high-strength engineering plastic (such as polycarbonate) to ensure structural strength while maintaining lightweight design.

[0031] For example, in some embodiments, the housing 10 may be formed by fastening the body and the end cap together with screws to facilitate the assembly and maintenance of internal components; or, in some embodiments, the housing 10 may be made in a one-piece molding manner, with assembly openings only left at specific locations to improve the overall sealing and structural rigidity.

[0032] The output end 20 is a key component of the high-precision micro servo motor 100, used for outputting torque and rotational motion. It is directly connected to an external load (such as a robot's articulated arm or a camera platform on a gimbal). The output end 20 is rotatably supported on the housing 10. In a possible implementation, the output end 20 is mounted on the housing 10 via bearings (such as ball bearings or sliding bearings), thereby enabling low-friction, high-precision rotational motion under the constraint of the housing 10. The output end 20 is typically a metal shaft or flange structure, which meshes with the last stage gear of the reduction gear set 40 to receive the power after reduction and torque amplification.

[0033] The motor 30, housed within the housing 10, is the power source for the high-precision micro servo motor 100. The motor 30 converts input electrical energy into mechanical energy, resulting in high-speed rotational motion. To meet the requirements of the micro servo motor regarding size and response speed, the motor 30 typically employs a high-performance brushed DC motor 30 or a brushless DC motor 30. Exemplarily, in some embodiments, the motor 30 can be a coreless motor 30, which features small size, high efficiency, and fast response to suit the structure of the micro servo motor.

[0034] The reduction gear set 40 is a transmission mechanism connecting the motor 30 and the output end 20. It converts the high-speed, low-torque rotary motion output by the motor 30 into low-speed, high-torque rotary motion to drive the output end 20 to drive the load. The reduction gear set 40 is typically composed of multiple gear pairs (such as spur gears) meshing sequentially. The output shaft of the motor 30 is connected to the first-stage gear, and the last-stage gear is connected to the output end 20. Because backlash is unavoidable between the gear pairs to ensure smooth rotation, this backlash accumulates in the gear set, forming "backlash." This causes a period of free travel at the output end 20 when a conventional servo motor rotates in the reverse direction, which in turn affects the reading accuracy of the potentiometer 50 when it is connected to the reduction gear set 40.

[0035] Potentiometer 50 is a sensing element in the high-precision micro servo motor 100 used to detect the actual position (angle) of the output terminal 20, and is the core feedback component of high-precision closed-loop control. Potentiometer 50 is located at one axial end of a certain stage gear in the reduction gear set 40 and is coaxially mounted with that stage gear. This means that the rotation axis of potentiometer 50 coincides with the rotation axis of that stage gear, and the rotor of potentiometer 50 is fixedly connected to that stage gear, thus enabling it to rotate synchronously with that stage gear. Since there is a fixed reduction ratio relationship between the rotation angle of that stage gear and the final output angle of the output terminal 20, the controller 70 can indirectly and accurately calculate the current absolute angular position of the output terminal 20 by measuring the angle of the potentiometer 50 rotor. Setting the potentiometer 50 in a certain stage of the reduction gear set 40 (instead of setting it directly on the output end 20) helps to improve the overall size of the servo motor, providing a structural basis for reducing the size of the servo motor in the axial direction of the output end 20. At the same time, this setting of the potentiometer 50 can also amplify the detection accuracy by utilizing the gear reduction ratio, and can avoid exposing the potentiometer 50 directly to a high torque environment, thereby protecting the potentiometer 50 and extending its service life.

[0036] Clutch 60 is a key control element connecting potentiometer 50 and the corresponding gear, used to selectively engage or disengage the power transmission between potentiometer 50 and the gear. That is, when clutch 60 is in the "engaged" state, the rotor of potentiometer 50 is rigidly connected to the gear, and the two rotate synchronously. At this time, potentiometer 50 can provide real-time and accurate feedback on the angular position of the gear (and thus indirectly feedback on the output terminal 20). When clutch 60 is in the "disengaged" state, the connection between the rotor of potentiometer 50 and the gear is cut off, and the two can move relatively independently.

[0037] The clutch 60 can be implemented in various ways. For example, in some embodiments, the clutch 60 can be an electromagnetic clutch 60, which controls engagement and disengagement by switching on and off electricity; or, in some embodiments, the clutch 60 can be a micro-mechanical clutch 60, which achieves engagement and disengagement through a shift fork mechanism driven by a micro electromagnet or shape memory alloy wire.

[0038] A positioning device is located on the housing 10 at a position corresponding to the output end 20, used to selectively lock the output end 20. The positioning device is another key actuator for the high-precision micro servo motor 100 to achieve hysteresis elimination. When the positioning device is in the "locked" state, the output end 20 is mechanically fixed in its current position and cannot rotate under external force or the drive of the internal motor 30; when the positioning device is in the "unlocked" state, the output end 20 can rotate freely. The positioning device can also be implemented in various ways.

[0039] For example, in some embodiments, the positioning device may include a pawl driven by a miniature electromagnet and a ratchet structure disposed on the output end 20. When the electromagnet is energized, the pawl lifts up to release the lock, and when the power is de-energized, the pawl falls into the ratchet tooth groove by spring force to lock. Alternatively, in some embodiments, the positioning device may also employ a miniature brake structure, which achieves locking by gripping the journal of the output end 20.

[0040] It should be noted that the high-precision micro servo motor 100 provided in this application embodiment has its various components working collaboratively through specific timing control logic to eliminate gear backlash and improve reversal accuracy. The specific control flow is as follows: When the high-precision micro servo motor 100 is moving and holding its position in one direction, all the gears in the reduction gear set 40 are in a state of contact (pressing) with their tooth surfaces on one side. At this time, if the control system commands the servo motor to move in the opposite direction (reverse), the direct drive motor 30 will reverse, resulting in an invalid idle stroke at the output end 20 before the gear backlash is completely eliminated.

[0041] To avoid this situation, when it is necessary to control the output terminal 20 to rotate in the reverse direction, this application adopts the following control logic: First, the positioning device locks the output end 20. At this time, the output end 20 is firmly fixed in its current position and cannot be rotated.

[0042] Next, clutch 60 disconnects potentiometer 50 from the corresponding gear. This step aims to discouple the rotor of potentiometer 50 from the reduction gear set 40, preventing unnecessary angle feedback signals from minute movements within the reduction gear set 40 during subsequent operations and avoiding misjudgments by the control system. It also prepares for subsequent "reverse drift."

[0043] Then, motor 30 reverses. Since output terminal 20 is locked by the positioning device at this time, the reverse torque of motor 30 is entirely converted into a force that causes relative movement of the gears inside reduction gear set 40. This force forces the tooth surfaces that were originally pressed together to separate and pushes the two gears in each gear pair to move to the other tooth surface until the other tooth surfaces also press together. This process is called "eliminating hysteresis". During this process, since output terminal 20 is locked, the external load will not move; since potentiometer 50 has been disengaged by clutch 60, potentiometer 50 will not be driven to rotate, thus avoiding data corruption.

[0044] Afterwards, once the motor 30 reverses and ensures that the other side of all gear teeth is engaged, the clutch 60 re-engages, causing the potentiometer 50 to re-synchronize with the gear of that stage. At this point, the angular position detected by the potentiometer 50 is the true position of the reduction gear set 40 after the backlash has been eliminated on the "reverse side".

[0045] Finally, the positioning device is unlocked. At this point, since all backlash in the reduction gear set 40 has been eliminated, a rigid, backlash-free transmission connection is formed between the output shaft of the motor 30 and the output end 20. Therefore, when the motor 30 continues to rotate in the reverse direction, the output end 20 will immediately follow the movement of the motor 30 without any idle travel, thus achieving high-precision reverse position control.

[0046] Through the structural design of the high-precision micro servo motor 100 and the timing coordination control between the components, the technical solution provided by the embodiments of this application can actively and accurately eliminate the inherent backlash in the reduction gear set 40, completely solve the problem of positioning delay and accuracy reduction caused by gear backlash when the traditional servo motor reverses, significantly improve the repeatability and dynamic response performance of the servo motor, and is especially suitable for fields such as micro robots and precision instruments with extremely high control accuracy requirements.

[0047] In some embodiments, the clutch 60 is an electromagnetic clutch 60, a friction clutch 60, or a jaw clutch 60; the positioning device is an electromagnetically actuated positioning device, a pneumatic positioning device, or a brake-type positioning device.

[0048] Clutch 60 can be an electromagnetic clutch 60, which controls the engagement and disengagement of the driving and driven components by switching the electromagnetic coil on and off, offering advantages such as fast response and simple control. In other embodiments, clutch 60 can be a friction clutch 60, which transmits torque through friction, resulting in a smoother engagement process and less impact. In still other embodiments, clutch 60 can also be a jaw clutch 60, which achieves rigid connection through the meshing of teeth on its end faces, resulting in no relative slippage after engagement and precise positional correspondence.

[0049] The positioning device can be an electromagnetically actuated positioning device, using a miniature electromagnet to drive the extension and retraction of the locking pin, thereby locking and releasing the output end 20. It has a simple structure and a large holding force. In other embodiments, the positioning device can be a pneumatic positioning device, using compressed air to drive a piston to move the locking element. This is suitable for special environments with strong electromagnetic interference or requiring explosion protection. In still other embodiments, the positioning device can also be a brake-type positioning device, achieving locking by applying a clamping force to the rotating shaft of the output end 20. This provides a large locking torque and requires no special machining of the rotating shaft.

[0050] Please refer to the following: Figures 1 to 3This application also provides a manufacturing method for producing the high-precision micro servo motor 100 provided in any of the foregoing embodiments, the manufacturing method comprising the following steps: Step S1: Install the motor 30 into the housing 10.

[0051] The purpose of this step is to provide a power source for the servo motor and establish the reference position of the motor 30 within the housing 10. Unlike existing technologies where the motor 30 is directly installed into the inner cavity of the housing 10, this application performs precision machining (e.g., boring in a single clamping operation) on the motor 30 mounting position on the housing 10 before installation to ensure that the axis of the motor 30 remains parallel to the reference axis of the subsequently installed reduction gear set 40. The motor 30 is fixed to the housing 10 using an interference fit or by locating screws to prevent displacement of the motor 30 due to vibration during operation, thereby reducing gear meshing errors caused by axis misalignment.

[0052] Step S2: Install the reduction gear set 40 inside the housing 10, and make its input stage drive-connected to the output shaft of the motor 30, and its final stage drive-connected to the output end 20.

[0053] The reduction gear set 40 of this application adopts a multi-stage planetary gear or spur gear combination structure. The key points lie in the installation sequence and axial positioning accuracy of each gear stage. Unlike the simple stacking of gears in existing technologies, this application requires sequential verification of the meshing backlash of each gear pair during installation to ensure that the coaxiality tolerance between the input stage and the output shaft of the motor 30 is controlled within 0.01mm. A thermal expansion compensation gap is reserved at the transmission connection between the final stage and the output end 20. Through step-by-step assembly and testing, the overall backlash can be controlled within the rated range.

[0054] Step S3: Rotatably mount the output terminal 20 onto the housing 10.

[0055] In these embodiments of this application, the output end 20 is mounted using a double bearing support structure. The inner ring of the bearing mates with the journal of the output end 20, and the outer ring mates with the bearing seat hole of the housing 10. During installation, an appropriate amount of grease should be applied to the inner ring of the bearing, and the output end 20 should be pressed into the bearing inner hole using a press-fit method. The press-fit force should be kept uniform and perpendicular to the axis. After installation, the output end 20 should be manually rotated to confirm that the rotation is flexible and without jamming, and the radial runout does not exceed 0.02 mm, providing rigid support for the stable meshing of the final stage gear.

[0056] Step S4: Install the clutch 60 on one axial end of a certain stage gear in the reduction gear set 40, and connect the driving end of the clutch 60 to the drive shaft of that stage gear.

[0057] The purpose of this step is to pre-install the clutch 60 as a power on / off control unit on the gear shaft, providing a structural basis for the subsequent controllable connection of the potentiometer 50.

[0058] In these embodiments of this application, the clutch 60 is a miniature electromagnetic clutch 60, with its driving end connected to the gear shaft and the driven end having a reserved interface structure for connecting the potentiometer 50. The clutch 60 should be installed after step S3 and before step S5, with the installation gap controlled within the range of 0.1mm to 0.3mm to ensure reliable torque transmission when the clutch 60 is engaged and complete disengagement without residual friction torque when disengaged. The coil leads of the clutch 60 need to be led out along the wire groove inside the housing 10 to avoid interference with moving parts. The design of this clutch 60 ensures that during normal operation, the clutch 60 is engaged, and the potentiometer 50 provides real-time position signal feedback; during hysteresis compensation parameter calibration, the clutch 60 periodically disengages, briefly separating the potentiometer 50 from the gear, thereby detecting the hysteresis in the gear transmission chain.

[0059] Step S5: Install potentiometer 50 on the driven end of clutch 60 and make potentiometer 50 coaxial with the gear of that stage.

[0060] The purpose of this step is to enable the position detection element to achieve controllable linkage with a certain stage of the reduction gear set 40 through the clutch 60, so as to obtain the angular position information of that stage of gear in real time.

[0061] This application mounts the potentiometer 50 on the driven end of the clutch 60, rather than directly on the gear shaft. This arrangement has the following advantages: First, the on / off control of the clutch 60 allows the potentiometer 50 to disengage from the gear when needed, thereby enabling online detection of backlash in the gear transmission chain. Second, the rotational speed of this gear stage is between the speed of the motor 30 and the output speed 20. The potentiometer 50 can obtain a suitable angular velocity at this position, avoiding both shortened lifespan at high speeds and insufficient signal update rate at low speeds. Third, the potentiometer 50 is coaxially mounted with this gear stage via the clutch 60, eliminating the influence of gear backlash in the transmission chain on position feedback, allowing the detection signal to directly reflect the actual rotation angle of the gear. During installation, a dedicated alignment fixture must be used to ensure that the coaxiality of the potentiometer 50 shaft with the driven end of the clutch 60 and the gear axis is no greater than 0.02 mm. A flexible coupling or flexible contacts are used for coupling to absorb assembly errors and thermal deformation.

[0062] Step S6: Install the positioning device on the housing 10 at the position corresponding to the output end 20.

[0063] The positioning device can be a photoelectric switch or a miniature mechanical limit switch. During installation, the positioning device must be fixed in the positioning groove of the housing 10, with its sensing surface facing the positioning feature (such as a boss, groove, or magnet) on the output terminal 20. The sensing gap should be controlled within the detection distance specified in the positioning device's specifications (typically 0.5mm to 2.0mm). The installation angle of the positioning device needs to be pre-calibrated using a position calibration fixture to ensure that the positioning device outputs a trigger signal when the output terminal 20 is in the mechanical limit position. This signal serves as the basis for the controller 70 to determine the absolute zero position of the output terminal 20.

[0064] Step S7: Connect the controller 70 to the motor 30, potentiometer 50, clutch 60 and positioning device electrically.

[0065] The controller 70 uses a flexible circuit board or a rigid circuit board, pre-installed in a dedicated slot within the housing 10. Electrical connections are made using soldered or crimped terminals, and the drive wires for the motor 30 should have a cross-sectional area of ​​not less than 0.1 mm². 2 High-temperature resistant wires are used to carry peak current; the signal line of potentiometer 50 should be shielded, with the shield grounded at one end on the controller 70 side to suppress electromagnetic interference; the control line of clutch 60 and the signal line of positioning device are respectively connected to the I / O port of controller 70. All wires should be routed along the preset wire grooves inside the housing 10 and secured with cable ties or tape to prevent the wires from contacting the gear meshing area when the servo vibrates. After the electrical connection is completed, continuity and insulation resistance tests must be performed to ensure there are no short circuits, open circuits, or leakage.

[0066] Step S8: Calibrate the hysteresis compensation parameters for the assembled servo motor.

[0067] The purpose of this step is to measure and compensate for the transmission backlash generated by the reduction gear set 40, thereby improving the repeatability and angle control accuracy of the servo motor. Unlike conventional simple backlash measurement, this application introduces a multi-parameter mathematical model, comprehensively considering factors such as gear backlash, wear degree, ambient temperature, and residual allowable error, to calculate an accurate backlash elimination benchmark value, providing a scientific basis for compensation for the controller 70.

[0068] In these embodiments of this application, the calibration of backlash compensation parameters is a key step that distinguishes it from existing servo manufacturing methods. In the prior art, servo motors rely solely on gear machining accuracy to ensure backlash after leaving the factory, or only perform simple idle distance measurements, ignoring the impact of wear evolution and environmental temperature changes on backlash. In contrast, this application automatically executes a calibration algorithm through the controller 70, storing the backlash elimination reference value calculated based on a mathematical model in the controller 70's storage unit, and correcting the output angle in real time during actual operation.

[0069] In some embodiments, step S8 includes: under the condition that the positioning device locks the output end 20, controlling the clutch 60 to disengage, driving the motor 30 to reverse, and recording the rotation angle Δθ of the motor 30 shaft required from the start of the motor 30 to the complete elimination of backlash by the reduction gear set 40. motor The hysteresis elimination reference value D of the servo motor is calculated according to the following formula. ref : Where, k total The total reduction ratio is from the motor shaft 30 to the output end 20; n is the total number of gear pairs in the reduction gear set 40; J i λ is the backlash arc length of the i-th gear pair; i R is the wear coefficient of the i-th stage gear pair, ranging from 0 to 0.3, with an initial value of 0; i Let be the reduction ratio of the i-th stage gear pair; α is the temperature influence coefficient, ranging from 0.01° / ℃ to 0.05° / ℃; T amb The ambient temperature during calibration is T0; the reference temperature is 20℃; Δθ res The preset residual allowable error angle ranges from 0.05° to 0.15°.

[0070] k total The value is obtained by multiplying the reduction ratios of each gear pair in the reduction gear set 40, i.e., k. total = R1×R2×...×R n The ratio is determined during the servo design phase and pre-stored in the storage unit of the controller 70. For example, for a four-stage planetary gear reduction mechanism, the total reduction ratio is typically between 120:1 and 500:1.

[0071] With the positioning device locking the output end 20, after the clutch 60 disengages, the drive motor 30 reverses direction. The rotation angle of the motor 30 shaft required from the start of the motor 30 to the complete elimination of hysteresis by the reduction gear set 40 is Δθ. motor The measured values ​​can be obtained through the Hall sensor or encoder built into the motor 30. During calibration, the output terminal 20 is mechanically locked by the positioning device, the clutch 60 is disengaged to separate the potentiometer 50 from the gear, and during the reverse rotation of the motor 30, the tooth backlash in the reduction gear set 40 is gradually eliminated. When the load current of the motor 30 shows a step increase (indicating that the gear has moved from the backlash side to the contact side), the angle rotated by the shaft of the motor 30 during this process is recorded.

[0072] The backlash arc length J of the i-th stage gear pair iThis refers to the arc length corresponding to the tooth backlash on the pitch circle of the gear pair, determined by the gear's design module, pressure angle, and tooth thickness deviation. Its value is calculated using gear parameters during the servo design phase and pre-stored in the storage unit of the controller 70. For example, for a micro gear with a module of 0.3mm and a pressure angle of 20°, the single-stage tooth backlash arc length J... i Typical values ​​range from 0.01 rad to 0.05 rad.

[0073] The wear coefficient λ of the i-th stage gear pair i This characterizes the backlash growth rate of the gear pair after actual operation, initially set to 0 (newly manufactured servo). During servo operation, the controller 70 can periodically re-execute the calibration program, comparing the difference between the currently calculated equivalent backlash and the initial backlash to infer and update λ. i value.

[0074] In these embodiments of this application, λ i The introduction of this feature enables the backlash compensation model to adapt to the accuracy degradation caused by gear wear, thus extending the effective service life of the servo. For example, for a servo that has been running for 1000 hours, the λ_i of the first three gear pairs may increase to 0.05 to 0.15, while the λ_i of the last gear pair may increase to 0.20 to 0.30 due to the larger load.

[0075] Reduction ratios R at each stage i The design of the servo motor is determined during the servo motor design phase and is pre-stored in the memory unit of the controller 70.

[0076] The temperature influence coefficient α reflects the effect of ambient temperature changes on the thermal expansion of the servo housing 10 and gear materials, as well as the viscosity of the lubricating grease, thus leading to the sensitivity of hysteresis changes. The specific value of α is pre-calibrated experimentally based on the material of the servo housing 10 (such as aluminum alloy or engineering plastic) and the type of lubricating grease, and stored in the controller 70. For example, for a servo using an aluminum alloy housing 10 and synthetic lubricating grease, α can be 0.02° / ℃; for a servo using an engineering plastic housing 10 and mineral lubricating grease, α can be 0.04° / ℃.

[0077] Ambient temperature T during calibration amb The temperature is read in real time by a temperature sensor installed on the controller 70 or inside the housing 10. When the calibration program starts, the controller 70 first reads T... amb Substitute this into the formula to perform temperature compensation calculation.

[0078] Preset residual allowable error angle Δθ res This is used to set the allowable residual error margin after hysteresis compensation, avoiding system oscillation caused by overcompensation. Wherein, Δθ resThe value of is determined based on the application scenario of the servo: for high-precision positioning applications (such as robot joints), a smaller value of 0.05° is used; for general model aircraft servos, a middle value of 0.10° is used; for applications with relatively low precision requirements, 0.15° is used. This value is treated as a subtraction item in the calibration program to ensure that the hysteresis after compensation is controlled within the allowable range.

[0079] In these embodiments of this application, the measured rotation angle Δθ of the 30-axis motor is obtained using the above formula. motor First, deduct the backlash of each gear pair (adjusted for wear coefficient and converted to the motor shaft 30 according to the reduction ratio) to obtain the effective rotation angle on the motor shaft 30 side used to overcome elastic deformation and lubrication resistance; then divide by the total reduction ratio k. total Converted to output 20; then subtract the additional hysteresis correction term α∙In(1+T) caused by ambient temperature. amb / T0); finally, subtract the preset residual allowable error angle Δθ. res The final hysteresis elimination benchmark value D is obtained. ref .

[0080] D ref After the calculation is completed, the controller 70 stores it in its internal memory. When the servo is working normally, and a change in rotation direction is needed, the controller 70 first reads D. ref In addition to the output target angle, D is superimposed. ref As a compensation, the backlash on the tooth flank of the motor 30 is eliminated in advance during commutation, thereby significantly reducing the position lag of the actual output end 20.

[0081] In these embodiments of this application, step S8 achieves precise quantification and compensation of servo backlash by introducing a multi-parameter mathematical model that includes backlash arc length, wear coefficient, ambient temperature, and residual error angle. Compared with the coarse calibration method in the prior art that relies solely on a single measured value, the calibration method of this application has the following advantages: First, the wear coefficient λ i The introduction of this feature allows the compensation model to adaptively adjust with the service life of the servo, avoiding compensation failure due to gear wear. Secondly, the temperature compensation term considers the influence of ambient temperature on the thermal expansion and lubrication characteristics of the servo, ensuring the consistency of calibration results and the effectiveness of compensation under different environments. Thirdly, the residual allowable error angle Δθ... res The settings provide the necessary stability margin for the control system, avoiding oscillations caused by overcompensation; fourth, the calibration method can be fully executed automatically by the controller 70 without manual intervention, making it suitable for batch calibration on the production line and periodic on-site calibration.

[0082] In some embodiments, the hysteresis elimination reference value D is repeatedly measured and calculated at multiple different angular positions at the output terminal 20. refThe average value is taken as the final calibration value and stored in the controller 70.

[0083] For example, a calibration position can be selected every 30° to 45° within the entire effective rotation range of the output terminal 20, for a total of 5 to 7 measurement points. At each measurement point, a complete D measurement is performed once according to the aforementioned steps. ref The calculation process yields the hysteresis elimination baseline value for that point, denoted as D. ref First point, D ref Secondly, and so on, up to D. ref The m-th point is defined as the total number of measurement points. Finally, the arithmetic mean of all measurement points is calculated, and this mean is stored as the final calibration value in the memory of the controller 70.

[0084] The specific parameters for multi-point calibration can be adjusted according to the accuracy requirements of the servo motor: for high-precision applications, the measurement point spacing can be 15° to 20°, and the number of measurement points should be no less than 10; for conventional applications, the measurement point spacing can be 45° to 60°, and the number of measurement points should be no less than 4. Each measurement point should be measured 2 to 3 times. If the range of multiple measurement results at the same position exceeds 0.1°, outliers should be removed and the measurement should be repeated.

[0085] In some embodiments, step S8 further includes action timing calibration: measuring the locking response time T from the time the controller 70 issues a locking command to the time the positioning device fully locks the output terminal 20. lock And the disconnection response time T from the time the controller 70 issues the disconnection command to the time the clutch 60 is fully disengaged. dis And verify that both satisfy the following formula: Where γ is the reliability coefficient of the lockout response time, with a value ranging from 1.5 to 3.0; σ lock The standard deviation of the lockout response time is measured multiple times; β is the load compensation coefficient, ranging from 0.8 to 1.2; M load The simulated load torque applied to output terminal 20 during calibration; M rated T is the rated output torque of the servo motor. margin This serves as a baseline safety margin, ranging from 5ms to 15ms.

[0086] The physical meaning of the formula is to ensure that clutch 60 has sufficient time to fully disengage before the positioning device locks. The left side of the inequality represents the completion time of the positioning device's locking action (the upper bound after considering reliability), and the right side represents the available time for clutch 60 to disengage (the lower bound after considering load effects). Only when the left side is less than or equal to the right side can it be guaranteed that clutch 60 completes its action before the positioning device, avoiding the situation where clutch 60 disengages only after the positioning device locks the output end 20, thereby preventing torque shock between the gear and potentiometer 50.

[0087] The first term T of the inequality lock +γ∙σ lock This is an upper bound estimate of the locking response time. Since the locking response of the positioning device exhibits random fluctuations, only the average value T is used. lock This is insufficient to reliably cover all cases. Introducing σ lock With γ, it can be guaranteed that the completion time of the locking action will not exceed the upper bound in a probabilistic sense. The larger the value of γ, the higher the reliability requirement.

[0088] The right side of the inequality, T dis Subtracting a load-related term represents the lower bound of the safe time for clutch 60 to disengage. dis These are measured values, but under load conditions, the load torque M load A reverse impact will occur at the moment the clutch disengages at 60, which may prolong the effective disengagement time.

[0089] The load compensation term is formally used to quantify this effect: the larger the load, the larger the value subtracted on the right, and the more stringent the requirements for disconnection time. When M... load When M is zero (no load), the compensation term is zero, and the requirement is the most lenient; when M load Equal to M rated When fully loaded, the compensation term reaches its maximum value β·T. margin The requirements are the most stringent.

[0090] For example, before calibrating the hysteresis elimination reference value, the action timing calibration is performed first. The controller 70 continuously issues locking and disengagement commands 10 to 20 times each, recording the time interval from each command issuance to the positioning device's feedback that locking is complete, and the time interval from each command issuance to the clutch 60's feedback that disengagement is complete. The average value and standard deviation σ of the locking response time are calculated. lock and the average disconnect response time T dis The reliability coefficient γ is set to 2.0, the load compensation coefficient β to 1.0, and the baseline safety time margin T. margin The value is 10ms. If the output terminal 20 is unloaded during calibration, then M... load If we take 0, then the square root term is 0, and the formula can be simplified to T. lockAdd 2.0 times σ lock Less than or equal to T dis Subtract 10ms. If the actual measured T... lock The mean is 8ms and the standard deviation is σ. lock If it is 1ms, then the left side is 10ms; T dis If the mean is 25ms, then the right side is 15ms, which satisfies the inequality requirement.

[0091] For load calibration, if a simulated load torque M is applied to the output terminal 20 during calibration... load Rated torque M rated 50%, then the square root of (M) load / M rated The value of β equals the square root of 0.5, which is approximately 0.71. Taking β as 1.0, subtracting 7.1 ms from the right side, we need to find the disconnection response time T. dis It must be large enough to satisfy the inequality. Actual measured T dis When the mean is 25ms, the right side is only 17.9ms. If T lock The mean is 8ms, σ lock The left side is 1ms, the right side is 10ms, and the inequality still holds. If T dis If the average is only 18ms, then the right side is 10.9ms, which is only slightly larger than the left side by 10ms. The safety margin is insufficient. At this time, it is necessary to adjust the drive current of clutch 60 or replace clutch 60 with one that has a faster response.

[0092] If the timing verification does not satisfy the inequality, the adjustments that can be made include: reducing the installation gap of the positioning device (lowering T). lock and σ lock Increase the drive voltage or current of clutch 60 (decrease T). dis Increase T within the allowable range; margin (Relax the requirements on the right). After adjustment, remeasurement and verification are required until the timing requirements are met before subsequent hysteresis elimination benchmark calibration can be performed.

[0093] In some embodiments, after installing the potentiometer 50 on the driven end of the clutch 60 in step S5, a zero-point calibration sub-step is also included: driving the motor 30 to rotate the output end 20 to the mechanical zero position, then adjusting the angle of the potentiometer 50 to make the output value of the potentiometer 50 zero, and finally locking the potentiometer 50.

[0094] The drive motor 30 rotates the output terminal 20 to the mechanical zero position. Specifically, the controller 70 sends a low-speed rotation command to the motor 30, controlling the rotation speed to be between 1° / s and 5° / s, so that the output terminal 20 slowly approaches the trigger position of the positioning device. When the positioning device outputs a trigger signal, the controller 70 immediately stops the motor 30, at which point the output terminal 20 is at the mechanical zero position. To ensure accurate positioning, a "pass-back" action can be performed: first, the drive motor 30 makes the output terminal 20 pass the mechanical zero position by about 1° to 2°, and then slowly retreats in the opposite direction until the positioning device triggers again, to eliminate the positioning error caused by unidirectional approach.

[0095] Then, adjust the angle of potentiometer 50 until its output value is zero. With output terminal 20 locked at the mechanical zero position, potentiometer 50 is connected to the gear shaft via clutch 60. Due to angular deviations in the installation of potentiometer 50, its output value is usually not zero. At this time, the operator or automatic calibration device rotates the housing 10 of potentiometer 50 (for housing 10 adjustable potentiometer 50) or the shaft of potentiometer 50 (for shaft adjustable potentiometer 50), while the controller 70 reads the AD sampling value of potentiometer 50 in real time. When the AD sampling value corresponds to zero angle, the adjustment stops.

[0096] Finally, tighten potentiometer 50. After potentiometer 50 is adjusted to the correct position, tighten the locking screws or nuts on its mounting bracket, or apply UV-curing adhesive to the adjusted area for fixation, to prevent the potentiometer 50 from shifting due to vibration during subsequent transportation or use.

[0097] After zero-point calibration is completed, verification can be performed: drive motor 30 again to make output terminal 20 leave the mechanical zero position (e.g., rotate 10° in the forward direction) and then return. After triggering the positioning device, read the output value of potentiometer 50. If the output value is still zero or the deviation is within 0.1% of the rated stroke, it is considered qualified; if the deviation exceeds the limit, the above calibration steps need to be repeated.

[0098] In some embodiments, during the zero-point calibration sub-step, the angle of potentiometer 50 is adjusted by a fine-tuning fixture with a resolution of 0.1°. After locking potentiometer 50, motor 30 is driven again to rotate output terminal 20 to the mechanical zero position. The output value of potentiometer 50 is then verified to be zero. If the deviation exceeds ±0.05°, the zero-point calibration sub-step is repeated until the requirements are met.

[0099] The fine-tuning fixture can employ a worm gear drive or a differential screw structure. In the worm gear drive, the worm gear is coupled to the part of the potentiometer 50 to be adjusted (housing 10 or shaft), and the input end of the worm is connected to a knob or stepper motor 30. Each rotation of the worm corresponds to a tooth-sized angle on the worm gear. By selecting appropriate numbers of worm threads and worm gear teeth, a 0.1° rotation of the potentiometer 50 can be achieved for each scale increment. In the differential screw structure, two screws with a pitch difference of 0.1mm can achieve a linear displacement of 0.1mm per rotation, which is then converted into an angular displacement of 0.1° via a lever or cam mechanism. The base of the fine-tuning fixture is fixed to the servo housing 10 or a dedicated calibration fixture to ensure that the fixture itself does not shift during adjustment.

[0100] After locking potentiometer 50, drive motor 30 again to rotate output terminal 20 to the mechanical zero position, and verify whether the output value of potentiometer 50 is still zero. Specifically, controller 70 performs the "over-return" positioning action again to return output terminal 20 precisely to the mechanical zero position, and then reads the output value of potentiometer 50. If the angle deviation corresponding to this output value exceeds ±0.05°, the zero-point calibration is deemed unqualified.

[0101] If the deviation exceeds ±0.05°, the zero-point calibration sub-step needs to be repeated until the requirements are met. The specific procedure for repeated calibration is as follows: First, loosen the locking device of potentiometer 50, and then make compensatory adjustments to the angle of potentiometer 50 using a fine-tuning fixture—if the deviation is positive (output value is too large), rotate one or more 0.1° scales of the fine-tuning fixture in the direction of decreasing the output value; if the deviation is negative, rotate in the opposite direction. After adjustment, relock, and drive motor 30 back to the mechanical zero position for verification. Record the deviation value after each round of adjustment until the deviation converges to within ±0.05°. For example, in mass production, the maximum number of repetitions can be set to 3 times. If it is still unqualified after 3 times, it is determined that there is an abnormality in the potentiometer 50 or the mounting structure of the servo motor, and rework is required.

[0102] In some embodiments, step S6 is followed by a locking function verification step: the control positioning device locks the output terminal 20 and applies 60% to 80% of the rated torque to the motor 30, and detects that the angle change of the output terminal 20 does not exceed 0.1°.

[0103] For example, after the positioning device is installed, the controller 70 issues a locking instruction to cause the positioning device to lock the output end 20 at the current position. The motor 30 is driven by the torque loading device or the controller 70 itself, and 70% of the rated torque is applied to the motor 30 as a verification load. The load is transmitted to the output end 20 through the reduction gear set 40, generating a torque impact on the locking state of the positioning device. During loading, the angle value of the output end 20 is monitored in real time by the potentiometer 50 or an external angle measurement device. If the angle change does not exceed 0.1°, the locking function of the positioning device is determined to be qualified; if the angle change exceeds 0.1°, it is necessary to check whether the installation clearance of the positioning device, whether the locking mechanism is stuck, or whether the driving circuit is normal, and retest after troubleshooting the fault.

[0104] The specific value of the verification load can be adjusted according to the application scenario of the steering gear: for products with high reliability requirements (such as robot joints), 80% of the rated torque can be applied for verification; for conventional aircraft model steering gears, applying 60% of the rated torque can meet the requirements. The number of verifications can be selected from 1 to 3 times. If multiple verifications are performed, after each verification, the locking shall be released and the output end 20 shall be rotated to different angle positions, then locked again for testing, so as to inspect the locking consistency of the positioning device at different angle positions.

[0105] In some embodiments, step S8 includes the following sub-steps performed sequentially: Step S81: position the output end 20 to a first calibration angle θ1, then perform the following reverse simulation actions sequentially: control the positioning device to lock the output end 20, control the clutch 60 to disengage, drive the motor 30 to reverse to eliminate the backlash of the reduction gear set 40, control the clutch 60 to re-engage, control the positioning device to release the lock, measure and record a first backlash compensation value B1; Step S82: rotate the output end 20 to a second calibration angle θ2, wherein θ2=θ1+90°, repeat step S81, measure and record a second backlash compensation value B2; Step S83: compare B1 and B2, if the absolute value of the difference between the two |B2-B1| is greater than a preset threshold ε, rotate the output end 20 sequentially to a third calibration angle θ3=θ1+180° and a fourth calibration angle θ4=θ1+270°, measure and record B3 and B4 respectively; Step S84: take the average value of B1, B2, B3, and B4 as the final backlash compensation value and store it in the controller 70.

[0106] For example, the value of the preset threshold ε ranges from 0.05° to 0.15°, and the specific value is determined according to the accuracy grade of the steering gear. For high-precision steering gears, ε can be 0.05°; for conventional steering gears, ε can be 0.10° or 0.15°.

[0107] The first calibration angle θ1 can be the mechanical zero position of the positioning device, or any starting angle within the effective rotation range of the output terminal 20. For example, θ1 is 0° (i.e., the trigger position of the positioning device). After step S81 is completed, the controller 70 drives the motor 30 to rotate the output terminal 20 90° forward to reach θ2, repeats the reverse simulation action and records B2.

[0108] If the absolute value of the difference between B1 and B2 does not exceed ε, it means that the backlash compensation values ​​measured at the two angular positions 90° apart at the output end 20 are basically the same, and the backlash characteristics of the gear transmission chain are relatively uniform throughout the entire circumference. At this time, the average value of B1 and B2 can be directly taken as the final backlash compensation value without the need to measure more points, thus saving calibration time.

[0109] If the absolute value of the difference between B1 and B2 is greater than ε, it indicates that the backlash characteristic has a significant angle dependence, which may be due to factors such as cumulative gear pitch error, tooth profile deviation, or installation eccentricity. In this case, it is necessary to further increase the number of measurement points. Rotate the output end 20 sequentially to θ3=θ1+180° and θ4=θ1+270° (i.e., four orthogonal positions with 90° intervals), and measure B3 and B4 respectively. Finally, take the average value of the measurement results at the four points as the final backlash compensation value to smooth out the influence of local backlash anomalies on the calibration results.

[0110] For example, in one calibration process, θ1 = 0°, ε = 0.08°, and B1 = 1.20°, B2 = 1.45° are measured. The absolute value of the difference is 0.25°, which is greater than 0.08°. Therefore, B3 and B4 are measured. B3 = 1.18° and B4 = 1.42° are measured. The average value is calculated as (1.20 + 1.45 + 1.18 + 1.42) / 4 = 1.3125°, and 1.31° is stored in controller 70. If initially B1 = 1.20° and B2 = 1.24°, and the absolute value of the difference is 0.04°, which is less than ε, then the average value of 1.22° can be directly taken as the final value, without needing to measure B3 and B4.

[0111] The advantages of this multi-point adaptive calibration strategy are: when the hysteresis characteristics are uniform, it automatically reduces the calibration time and improves production efficiency; when the hysteresis characteristics are uneven, it automatically increases the number of measurement points to ensure compensation accuracy, thus achieving a balance between calibration efficiency and accuracy.

[0112] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0113] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A high-precision miniature servo motor, characterized in that, include: case; The output end is rotatably supported on the housing; The motor is housed within the housing; A reduction gear set connects the motor to the output terminal; A potentiometer is disposed at one axial end of a certain stage gear in the reduction gear set and is coaxially disposed with that stage gear. A clutch, connected between the potentiometer and the corresponding gear, is used to selectively engage or disengage the power transmission between the potentiometer and the gear; as well as A positioning device is disposed on the housing at a position corresponding to the output end, for selectively locking the output end; When the high-precision micro servo motor needs to reverse, the positioning device first locks the output end, the clutch then disconnects the potentiometer from the corresponding gear, the motor reverses to eliminate the backlash of the reduction gear set, and then the clutch re-engages and the positioning device is unlocked.

2. The high-precision micro servo motor according to claim 1, characterized in that, The clutch is an electromagnetic clutch, a friction clutch, or a jaw clutch; the positioning device is an electromagnetically actuated positioning device, a pneumatic positioning device, or a brake-type positioning device.

3. A method for manufacturing the high-precision micro servo motor as described in claim 1 or 2, characterized in that, Includes the following steps: Step S1: Install the motor into the housing; Step S2: Install the reduction gear set inside the housing, and make its input stage drive-connected to the output shaft of the motor, and its final stage drive-connected to the output end; Step S3: Rotatably mount the output terminal to the housing; Step S4: Install the clutch on one axial end of a certain stage gear in the reduction gear set, and connect the driving end of the clutch to the drive shaft of that stage gear. Step S5: Install the potentiometer on the driven end of the clutch and make the potentiometer coaxial with the gear of that stage; Step S6: Install the positioning device on the housing at the position corresponding to the output end; Step S7: Electrically connect the controller to the motor, the potentiometer, the clutch, and the positioning device; Step S8: Calibrate the hysteresis compensation parameters for the assembled servo motor.

4. The manufacturing method according to claim 3, characterized in that, Step S8 includes: under the condition that the positioning device locks the output end, controlling the clutch to disengage, driving the motor to reverse, and recording the motor shaft rotation angle Δθ required from motor start-up to the complete elimination of backlash by the reduction gear set. motor The hysteresis elimination reference value D of the servo motor is calculated according to the following formula. ref : Where, k total The total reduction ratio is from the motor shaft to the output end; n is the total number of gear pairs in the reduction gear set; J i λ is the backlash arc length of the i-th gear pair; i R is the wear coefficient of the i-th stage gear pair, ranging from 0 to 0.3, with an initial value of 0; i Let be the reduction ratio of the i-th stage gear pair; α is the temperature influence coefficient, ranging from 0.01° / ℃ to 0.05° / ℃; T amb The ambient temperature during calibration is T0; the reference temperature is 20℃; Δθ res The preset residual allowable error angle ranges from 0.05° to 0.15°.

5. The manufacturing method according to claim 4, characterized in that, The hysteresis elimination reference value D was repeatedly measured and calculated at multiple different angular positions at the output terminal. ref The average value is taken as the final calibration value and stored in the controller.

6. The manufacturing method according to claim 3, characterized in that, Step S8 further includes action timing calibration: measuring the locking response time T from when the controller issues a locking command to when the positioning device fully locks the output terminal. lock And the disconnection response time T from the time the controller issues a disconnection command to the time the clutch is fully disengaged. dis And verify that both satisfy the following formula: Where γ is the reliability coefficient of the lockout response time, with a value ranging from 1.5 to 3.0; σ lock The standard deviation of the locking response time is measured multiple times; β is the load compensation coefficient, ranging from 0.8 to 1.2; M load M is the simulated load torque applied to the output terminal during calibration; rated T is the rated output torque of the servo motor. margin This serves as a baseline safety margin, ranging from 5ms to 15ms.

7. The manufacturing method according to claim 3, characterized in that, In step S5, after the potentiometer is installed on the driven end of the clutch, a zero-point calibration sub-step is also included: driving the motor to rotate the output end to the mechanical zero position, then adjusting the angle of the potentiometer to make the output value of the potentiometer zero, and finally locking the potentiometer.

8. The manufacturing method according to claim 7, characterized in that, In the zero-point calibration sub-step, the angle of the potentiometer is adjusted by a fine-tuning fixture with a resolution of 0.1°. After locking the potentiometer, the motor is driven again to rotate the output terminal to the mechanical zero position to verify whether the output value of the potentiometer is still zero. If the deviation exceeds ±0.05°, the zero-point calibration sub-step is repeated until the requirements are met.

9. The manufacturing method according to claim 3, characterized in that, Step S6 is followed by a locking function verification step: controlling the positioning device to lock the output end, and applying 60% to 80% of the rated torque to the motor, and detecting that the angle change of the output end does not exceed 0.1°.

10. The manufacturing method according to claim 3, characterized in that, Step S8 includes the following sub-steps: Step S81: Position the output end to the first calibration angle θ1, and then perform the following reverse simulation actions in sequence: control the positioning device to lock the output end, control the clutch to disengage, drive the motor to reverse to eliminate the backlash of the reduction gear set, control the clutch to re-engage, control the positioning device to unlock, and measure and record the first backlash compensation value B1. Step S82: Rotate the output terminal to the second calibration angle θ2, where θ2 = θ2 + 90°, repeat step S81, measure and record the second hysteresis compensation value B2; Step S83: Compare B1 and B2. If the absolute value of the difference between the two, |B2-B1|, is greater than the preset threshold ε, then rotate the output terminal to the third calibration angle θ3=θ1+180° and the fourth calibration angle θ4=θ1+270° in sequence, and measure and record B3 and B4 respectively. Step S84: Take the average value of B1, B2, B3, and B4 as the final hysteresis compensation value and store it in the controller.

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