Clearance compensation method for actuator

Abstract

The invention provides a clearance compensation method for an actuator. The method comprises the following steps: acquiring a fixed clearance value of the actuator; in response to the fact that a load is applied to the actuator, the current position of the actuator is obtained, the actuator is controlled to conduct full-stroke two-way operation, and the load direction of the load is judged according to operation information; based on the load direction, determining the gap orientation of the gap; compensating the limit endpoint value of the whole stroke according to the gap orientation and the fixed gap value; and establishing a corresponding relation between a control signal and the current position based on the compensated limit endpoint value.

Description

Technical Field

[0001] This application relates to the field of motor control, and more specifically, to a method for backlash compensation of actuators, electronic devices, and computer-readable storage media. Background Technology

[0002] In building automation systems, actuators are used to precisely adjust valve openings based on control signals, thereby controlling parameters such as temperature. The control accuracy directly affects the valve adjustment effect. However, the inherent backlash between the mechanical transmission components of the actuator (such as gears and lead screws) can lead to positioning errors, which is a key issue restricting the improvement of its accuracy.

[0003] Existing technologies primarily rely on additional sensors for position detection to compensate for backlash, such as potentiometers or magnetic coils to measure the actual position of the actuator. However, potentiometer solutions are limited by sampling accuracy and require additional transmission gears, resulting in limited accuracy and increased costs. Magnetic coil solutions, on the other hand, suffer from frequency detection delays, leading to lagging position information acquired during movement and failing to meet high-precision control requirements. Therefore, effectively compensating for transmission backlash without introducing additional errors and costs has become a key technical challenge for improving the overall control accuracy of actuators and valves. Summary of the Invention

[0004] According to one aspect of this application, a backlash compensation method for an actuator is provided, the method comprising: acquiring a fixed backlash value of the actuator; in response to an applied load on the actuator, acquiring the current position of the actuator and controlling the actuator to perform bidirectional operation of the entire stroke, and determining the load direction of the load based on the operation information; determining the backlash orientation based on the load direction; compensating the limit endpoint value of the entire stroke according to the backlash orientation and the fixed backlash value; and establishing a correspondence between a control signal and the current position based on the compensated limit endpoint value.

[0005] The method, as an example or additionally, includes determining the load direction of the load based on the operating information by: obtaining a first average operating current in the first operating direction and a second average operating current in the second operating direction during the bidirectional operation; comparing the magnitudes of the first average operating current and the second average operating current to determine the load direction, wherein the operating direction with the larger average operating current is opposite to the load direction, and the operating direction with the smaller average operating current is the same as the load direction.

[0006] The method, as an example or additionally, includes determining the gap orientation based on the load direction as follows: if the load direction is toward a first limit endpoint of the full travel, then the gap orientation is determined to be located at the first limit endpoint; if the load direction is toward a second limit endpoint of the full travel, then the gap orientation is determined to be located at the second limit endpoint.

[0007] The method, as an example or additionally, includes the following steps: if the gap orientation is located at the first limit endpoint, the limit endpoint value of the first limit endpoint is compensated to H1-ΔH, where H1 is the limit endpoint value of the first limit endpoint before compensation, and ΔH is the fixed gap value; if the gap orientation is located at the second limit endpoint, the limit displacement value of the second limit endpoint is compensated to H2+ΔH, where H2 is the limit endpoint value of the second limit endpoint before compensation.

[0008] The method, for example or additionally, further includes obtaining the current position of the actuator and controlling the actuator to perform bidirectional operation of the full stroke by calibrating the current position before controlling the actuator to perform bidirectional operation of the full stroke.

[0009] The method, for example or additionally, further includes: storing the load direction and the corresponding compensated limit endpoint value.

[0010] The method, as an example or additionally, further includes: when the actuator is powered on, obtaining the current power-on position of the actuator; reading the stored load direction and the corresponding compensated limit endpoint value; determining whether the current power-on position is located at the limit endpoint corresponding to the gap orientation; if so, taking the compensated limit endpoint value as the current position of the actuator; if not, taking the current power-on position as the current position.

[0011] The method, as an example or additionally, further includes: when the actuator is powered on, obtaining the current power-on position of the actuator; reading the stored load direction and the corresponding compensated limit endpoint value; determining whether the following conditions are met: the current power-on position is located at the limit endpoint corresponding to the gap orientation and the deviation between the current power-on position and the compensated limit endpoint value is less than a preset threshold; if met, then the compensated limit endpoint value is taken as the current position of the actuator; if not met, then the current power-on position is taken as the current position.

[0012] The method, for example or additionally, includes an actuator comprising: a motor, a lead screw, a Hall sensor, and a magnetic coil, wherein the Hall sensor is used to detect the number of rotations of the motor within the full stroke to generate a Hall stroke, and the magnetic coil is used to detect the absolute position of the lead screw within the full stroke to generate a coil stroke.

[0013] The method, for example or additionally, involves obtaining the fixed gap value by the difference between the average of the Hall strokes of the plurality of actuators and the average of the coil strokes.

[0014] An electronic device is also provided, comprising a memory and a processor, the memory storing program instructions, wherein the processor, when executing the program instructions, performs the gap compensation method according to one aspect of this application.

[0015] A computer-readable storage medium is also provided, the computer-readable storage medium storing instructions that, when executed by a processor, implement the gap compensation method according to one aspect of this application. Attached Figure Description

[0016] This application will be more fully understood by referring to the following detailed description of specific embodiments in conjunction with the accompanying drawings, wherein the same reference numerals in the drawings refer to the same elements, wherein: Figure 1 This is a flowchart of a backlash compensation method 100 for an actuator according to an embodiment of this application; Figure 2 This is a flowchart of a power-on position compensation method 200 for an actuator according to an embodiment of this application. Detailed Implementation

[0017] The following are some embodiments of this application, intended to provide a basic understanding of the application. They are not intended to identify key or decisive elements of the application or to limit the scope of protection sought.

[0018] For purposes of brevity and illustrative purposes, the principles of this application are described herein primarily with reference to exemplary embodiments thereof. However, those skilled in the art will readily recognize that the same principles are equivalently applicable to all types of backlash compensation methods for actuators, electronic devices, and computer-readable storage media in which these same principles can be implemented, and that any such variations do not depart from the true spirit and scope of this patent application.

[0019] Furthermore, reference is made in the accompanying drawings, which illustrate specific exemplary embodiments. Electrical, mechanical, logical, and structural modifications may be made to these embodiments without departing from the spirit and scope of this application. Moreover, while features of this application are disclosed in conjunction with only one of several embodiments, such features may be combined with one or more other features of other embodiments if desired and / or advantageous for any given or identifiable function. Therefore, the following description should not be construed as limiting, and the scope of this application is defined by the appended claims and their equivalents.

[0020] Terms such as "possessing" and "comprising" indicate that, in addition to the units (modules) and steps directly and explicitly stated in the specification and claims, the technical solution of this application does not exclude the presence of other units (modules) and steps not directly or explicitly stated. Terms such as "first" and "second" do not indicate the order of the units in terms of time, space, size, etc., but are merely used to distinguish the units. Furthermore, the steps in this document are not limited to being performed in the order they are written; a step written later may be performed simultaneously with or before a step written earlier.

[0021] Figure 1 This is a flowchart of a backlash compensation method 100 for an actuator, based on some specific examples of this application. In some embodiments, the actuator may be a linear actuator, comprising: a motor, a leadscrew driven to rotate by the motor, a Hall sensor for detecting the number of rotations of the motor, and a magnetic coil for detecting the absolute position of the leadscrew. Figure 1 As shown, the method includes: Step S110: Obtain the fixed backlash value of the actuator. In this step, obtaining the fixed backlash value (ΔH) is the basis for backlash compensation. Specifically, before the actuator leaves the factory, multiple actuator samples can be calibrated. The sample actuator is controlled to complete one full stroke, i.e., from one end of the mechanical limit to the other. During this process, the number of motor rotations is accumulated by the Hall sensor to obtain the Hall stroke (A) corresponding to the full stroke. Simultaneously, the absolute position of the lead screw is detected by the magnetic coil; the difference between its starting and ending positions is the coil stroke (B) corresponding to the full stroke. Due to the mechanical backlash, the Hall stroke A measured by the motor side is usually greater than the coil stroke B measured by the lead screw side. The fixed backlash value ΔH is obtained by calculating the difference between the average Hall stroke and the average coil stroke, i.e., ΔH = A - B. This ΔH is a systematic fixed value, representing the total backlash in the entire transmission chain in terms of stroke. This pre-shipment calibration method allows for the batch, efficient, and accurate acquisition of this key parameter, eliminating the need for complex measurements using high-cost sensors on each actuator and significantly reducing costs.

[0022] Step S120: In response to the actuator being loaded, the current position of the actuator is acquired and the actuator is controlled to perform bidirectional operation throughout its full stroke. The load direction is determined based on the operating information. This step is the core of the adaptive process. This adaptive function is triggered when the actuator is installed in the actual working condition (such as a valve) and a load is applied. Specifically, when the actuator is loaded and powered on, the current absolute position of the lead screw can be acquired via a magnetic induction coil, and then the adaptive function of the actuator is triggered. In some embodiments, after the actuator is loaded and powered on, and before bidirectional operation begins (i.e., the adaptive function is executed), the previously acquired current absolute position can be calibrated via a magnetic induction coil (i.e., the starting point of the displacement measurement based on the Hall sensor is calibrated). This calibration step is crucial. It ensures the accuracy of the reference position for subsequent adaptive operation, especially when the actuator stroke changes due to valve installation or replacement. It effectively avoids control errors caused by reference drift, improving the robustness and adaptability of the method.

[0023] Subsequently, the actuator, carrying the load, performs a complete bidirectional operation, moving from its current position to both mechanical limit endpoints of its full stroke. During this bidirectional operation, the first average operating current (I_up) in the first operating direction (e.g., upward / opening direction) and the second average operating current (I_down) in the second operating direction (e.g., downward / closing direction) are acquired. The determination of the load direction is based on the following physical principle: when the motor rotation direction is opposite to the load force direction (i.e., work is done to overcome the load), a larger torque is required, resulting in a larger operating current; conversely, when the motor rotation direction is the same as the load force direction, the load force assists the movement, resulting in a smaller operating current. Therefore, the load direction can be determined by comparing the magnitudes of I_up and I_down: the operating direction with a larger average operating current is opposite to the load direction, and the operating direction with a smaller average operating current is the same as the load direction. For example, if I_up > I_down, it indicates that the upward movement requires overcoming greater resistance, therefore the load direction is downward (i.e., attempting to close the valve). This method utilizes the actuator's existing current detection function, intelligently identifying the load direction without adding additional hardware, achieving low-cost, highly integrated adaptive judgment.

[0024] Step S130: Determine the clearance orientation based on the load direction. Specifically, the orientation of the mechanical clearance is not fixed but determined by the load direction. When the actuator is subjected to a unidirectional load, the gears, lead screws, and other components in the transmission mechanism will always be close to one side of the meshing surface under the load force, thus "squeezing" all mechanical clearances and fixing them to the same side of the load direction. Based on the load direction determined in step S120, the clearance orientation can be determined: if the load direction is towards the first limit endpoint of the full stroke (e.g., the start endpoint / closed position H1), the clearance orientation is determined to be on the side of the first limit endpoint; if the load direction is towards the second limit endpoint of the full stroke (e.g., the end endpoint / open position H2), the clearance orientation is determined to be on the side of the second limit endpoint. This step directly associates the abstract mechanical clearance position with the detectable load direction, providing a theoretical basis for subsequent accurate compensation.

[0025] Step S140: Compensate the limit endpoint value of the entire stroke based on the gap orientation and fixed gap value. Specifically, this step involves "translating" the control coordinate system to eliminate the influence of the gap. The purpose of compensation is to redefine the effective control stroke and exclude the gap region from the linear control range. The specific compensation method is as follows: It should be noted that in the embodiments of this application, H1 and H2 are the Hall start and end values ​​of the entire stroke, where H1>H2. If the gap orientation is located on the first limit endpoint side (H1 side), the limit endpoint value of the first limit endpoint is compensated to H1-ΔH. This means that the effective starting point of the control system changes from H1 to H1-ΔH, and the rotation of the motor in the interval from H1 to H1-ΔH is only for eliminating the gap by idling and will not drive the valve to move, thereby ensuring that the control command starting from H1-ΔH corresponds precisely to the valve position. If the gap orientation is located on the second limit endpoint side (H2 side), the limit endpoint value of the second limit endpoint is compensated to H2+ΔH. The principle is the same as above, with the effective control endpoint shifted inward.

[0026] Additionally, in some embodiments, the determined load direction and the compensated limit endpoint values ​​are stored in non-volatile memory (such as Flash). Provided the load direction remains unchanged, the actuator can directly read and use these values ​​upon the next power-on, eliminating the need for a time-consuming adaptive process and improving efficiency.

[0027] Step S150: Based on the compensated limit endpoint values, establish the correspondence between the control signal and the current position. Specifically, after compensation, using the new, valid limit endpoints (e.g., H1-ΔH and H2, or H1 and H2+ΔH) as a reference, re-establish the linear relationship between the control signal (e.g., 0-10V voltage signal or 0-100% opening command) and the actuator position. Subsequently, the control system will drive the motor based on this new linear relationship that eliminates backlash errors, enabling the valve to precisely stop at the position required by the command, greatly improving control accuracy.

[0028] Figure 2 This is a flowchart of a power-on position compensation method 200 for an actuator according to an embodiment of this application. This method is used for position initialization of the actuator upon power-on after adaptive compensation has been completed.

[0029] like Figure 2 As shown, the method includes: step S210: when the actuator is powered on, obtain the current power-on position of the actuator; step S220: read the stored load direction and the corresponding compensated limit endpoint value; In some embodiments, the next step is S230: determining whether the current power-on position is located at the limit endpoint corresponding to the gap orientation.

[0030] Next, in step S240: if the judgment result of step S230 is "yes" (i.e., the current position is at the endpoint upon power-up), then the stored compensated limit endpoint value is used as the current position value. This is done because when the actuator stops exactly at the endpoint where the gap is located, the absolute position measured by the coil is the mechanical endpoint position including the gap, while the compensated logical endpoint value used for control is the correct position coordinate. Using this value as the current position avoids introducing an initial error in the gap amount upon power-up.

[0031] In step S250: If the judgment result of step S230 is "no" (i.e., the current position after power-on is not located at the endpoint), then the current absolute position after power-on calculated by the coil is directly used as the current position value.

[0032] In another embodiment, an additional power-on position compensation method 200 is provided. Steps S210 and S220 of this power-on position compensation method 200 are the same as steps S210-S220 of the previous embodiment, and will not be described again here. After step S220, the process proceeds to step S230, in which it is determined whether the current power-on position meets the following conditions: the current power-on position is located at the limit endpoint corresponding to the gap orientation, and the deviation between the current power-on position and the compensated limit endpoint value is less than a preset threshold (e.g., 1% of the full stroke); this threshold is used to prevent miscompensation caused by minor vibrations or measurement noise.

[0033] Next, in step S240: if it is determined in step S230 that the above conditions are met (i.e., the current position is at the limit endpoint and the deviation is less than a preset threshold), then the stored compensated limit endpoint value is used as the current position value. This is because when the actuator stops exactly at the endpoint where the gap is located, the absolute position measured by the coil is the mechanical endpoint position including the gap, while the compensated logical endpoint value used for control is the correct position coordinate. Using this value as the current position avoids introducing an initial error in the gap amount upon power-on.

[0034] Step S250: If it is determined in step S230 that the above conditions are not met, then the current absolute position calculated by the coil is directly used as the current position value.

[0035] It should be noted that the judgment in step S230 requires the following two conditions to be met simultaneously: the current power-on position is located at the limit endpoint corresponding to the gap orientation; and the deviation between the current power-on position and the compensated limit endpoint value is less than a preset threshold. If either condition is not met, the process proceeds to step S250, where the current absolute power-on position calculated by the coil is directly used as the current position value.

[0036] Step S260: Finally, based on the acquired current position value (which can be the current absolute position calculated by the coil or the stored compensated limit endpoint value), the system uses the linear relationship between the control signal and position established during adaptive backlash compensation to control the motor to run to the target position, achieving high-precision control. This power-on position compensation method solves the problem of "virtual position" error in the magnetic coil reading when the lead screw stops exactly at the backlash endpoint after the actuator is powered off and restarted.

[0037] According to another aspect of this application, an electronic device is also provided. The electronic device includes a memory and a processor, the memory storing program instructions that, when executed by the processor, implement the backlash compensation method for an actuator according to any of the foregoing embodiments.

[0038] According to another aspect of this application, a computer-readable storage medium for storing instructions is also provided, which, when executed by a processor or processing module, performs a backlash compensation method for an actuator according to any embodiment of this application.

[0039] The computer-readable storage medium, memory, storage unit, storage module, etc., referred to in this application include various types of computer-readable storage media, which can be any available medium accessible by a general-purpose or special-purpose computer. For example, a computer-readable medium may include RAM, ROM, EPROM, E2PROM, registers, hard disk, removable disk, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other temporary or non-temporary medium capable of carrying or storing desired program code units in the form of instructions or data structures, accessible by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Combinations of the above should also be included within the scope of protection of computer-readable media. An exemplary storage medium is coupled to a processor so that the processor can read and write information from / to the storage medium. In an alternative, the storage medium may be integrated into the processor. The processor and storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In an alternative, the processor and storage medium may reside as discrete components in the user terminal.

[0040] In summary, the embodiments of this application propose a backlash compensation technology for actuators. By combining the relative displacement measurement of Hall sensors and the absolute position measurement of magnetic coils, and innovatively utilizing a load direction adaptive mechanism, precise compensation for fixed mechanical backlash is achieved. This effectively eliminates the influence of mechanical backlash on the actuator's positioning accuracy, making valve control more precise. Furthermore, it adds an initial power-on position calibration and threshold judgment mechanism to avoid erroneous compensation caused by stroke changes or measurement noise. The system is highly adaptable, stable in operation, and fully utilizes existing actuator sensors (such as Hall sensors, coils, and current sensors), eliminating the need for high-cost external sensors such as potentiometers, thus achieving "soft compensation."

[0041] The foregoing primarily describes the backlash compensation method for actuators, electronic devices, and computer-readable storage media of this application. Although only some specific embodiments of this application have been described, those skilled in the art should understand that this application can be implemented in many other forms without departing from its spirit and scope. Therefore, the examples and embodiments shown are considered illustrative rather than restrictive, and various modifications and substitutions may be made without departing from the spirit and scope of this application as defined by the appended claims.

Claims

1. A method for backlash compensation in an actuator, characterized in that, The method includes: Obtain the fixed gap value of the actuator; In response to the actuator being loaded, the current position of the actuator is obtained and the actuator is controlled to run bidirectionally throughout its full stroke, and the load direction of the load is determined based on the running information; Based on the load direction, determine the orientation of the gap; Based on the gap orientation and the fixed gap value, the limit endpoint value of the entire stroke is compensated; and Based on the compensated limit endpoint value, a correspondence between the control signal and the current position is established.

2. The method according to claim 1, characterized in that, The step of determining the load direction based on the operating information includes: obtaining the first average operating current in the first operating direction and the second average operating current in the second operating direction during the bidirectional operation; comparing the magnitudes of the first average operating current and the second average operating current to determine the load direction, wherein the operating direction with the larger average operating current is opposite to the load direction, and the operating direction with the smaller average operating current is the same as the load direction.

3. The method according to claim 1 or 2, characterized in that, The step of determining the gap orientation based on the load direction includes: if the load direction is toward the first limit endpoint of the full stroke, then the gap orientation is determined to be located at the first limit endpoint; if the load direction is toward the second limit endpoint of the full stroke, then the gap orientation is determined to be located at the second limit endpoint.

4. The method according to claim 3, characterized in that, The compensation for the limit endpoint value of the entire stroke includes: if the gap orientation is located at the first limit endpoint, then the limit endpoint value of the first limit endpoint is compensated to H1-ΔH, where H1 is the limit endpoint value of the first limit endpoint before compensation, and ΔH is the fixed gap value; if the gap orientation is located at the second limit endpoint, then the limit displacement value of the second limit endpoint is compensated to H2+ΔH, where H2 is the limit endpoint value of the second limit endpoint before compensation.

5. The method according to claim 1, characterized in that, The step of obtaining the current position of the actuator and controlling the actuator to perform bidirectional operation throughout its full stroke further includes: calibrating the current position before controlling the actuator to perform bidirectional operation throughout its full stroke.

6. The method according to claim 4, characterized in that, The method further includes storing the load direction and the corresponding compensated limit endpoint values.

7. The method according to claim 6, characterized in that, The method further includes: When the actuator is powered on, the current power-on position of the actuator is obtained; Read the stored load direction and the corresponding compensated limit endpoint value; Determine whether the current power-on position is located at the limit endpoint corresponding to the gap orientation. If yes, use the compensated limit endpoint value as the current position of the actuator; otherwise, use the current power-on position as the current position.

8. The method according to claim 6, characterized in that, The method further includes: When the actuator is powered on, the current power-on position of the actuator is obtained; Read the stored load direction and the corresponding compensated limit endpoint value; Determine whether the following conditions are met: the current power-on position is located at the limit endpoint corresponding to the gap orientation and the deviation between the current power-on position and the compensated limit endpoint value is less than a preset threshold; if met, the compensated limit endpoint value is taken as the current position of the actuator; if not met, the current power-on position is taken as the current position.

9. The method according to claim 1, characterized in that, The actuator includes a motor, a lead screw, a Hall sensor, and a magnetic coil, wherein the Hall sensor is used to detect the number of rotations of the motor within the full stroke to generate a Hall stroke, and the magnetic coil is used to detect the absolute position of the lead screw within the full stroke to generate a coil stroke.

10. The method according to claim 9, characterized in that, The fixed gap value is obtained by the difference between the average value of the Hall stroke of the multiple actuators and the average value of the coil stroke.

11. An electronic device, characterized in that, The electronic device includes: A memory, wherein program instructions are stored; A processor that, when executing the program instructions, implements the gap compensation method according to any one of claims 1 to 10.

12. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores instructions that, when executed by a processor, perform the gap compensation method according to any one of claims 1 to 10.

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