Motor speed control method, device, equipment and storage medium

Abstract

The present application relates to the technical field of motor control, and particularly relates to a motor rotating speed control method, device, equipment and storage medium, the method comprising: acquiring an assembly process flow, and determining a standard assembly rotating speed table according to the assembly process flow; collecting a current torque of the motor and a current remaining thread length of a screw rod to be assembled; determining an assembly state of the screw rod to be assembled according to the standard assembly rotating speed table, the current torque and the current remaining thread length; selecting a corresponding rotating speed control strategy based on the assembly state, and adjusting the current rotating speed of the motor through the rotating speed control strategy; since the current torque of the motor and the current remaining thread length of the screw rod to be assembled are compared with the standard assembly rotating speed table, the assembly state of the screw rod to be assembled can be determined, and the rotating speed of the motor is adjusted according to the current assembly state, the rotating speed of the motor can be adjusted according to the current remaining thread length, the service life is increased, and the control torque accuracy is improved.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, and in particular to a method, apparatus, device, and storage medium for controlling motor speed. Background Technology

[0002] Currently, with the development of technology, traditional manual screwdrivers are gradually being replaced by electric screwdrivers, which have advantages such as high efficiency and labor saving.

[0003] Existing electric screwdrivers typically control the motor to rotate at a preset speed, causing the screw to rotate at the same speed. However, when the screw is about to be tightened, the motor is still at high speed, which causes the motor to encounter greater resistance at this time, resulting in the motor burning out and having a shorter service life. At the same time, the inertia of the motor can also cause problems such as inaccurate tightening torque values.

[0004] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main objective of this invention is to provide a method, device, equipment, and storage medium for controlling motor speed, aiming to solve the technical problem in the prior art where the motor is still at high speed when the screw is about to be tightened, resulting in a short service life of the motor.

[0006] To achieve the above objectives, the present invention provides a motor speed control method, the method comprising the following steps:

[0007] The assembly process flow is obtained, and a standard assembly speed table is determined based on the assembly process flow. The standard assembly speed table stores a mapping relationship table between the remaining thread length of the screw to be assembled and the real-time torque of the motor at each assembly moment.

[0008] Collect the current torque of the motor and the current remaining thread length of the screw to be assembled;

[0009] The assembly state of the screw to be assembled is determined based on the standard assembly tachometer, the current torque, and the current remaining thread length.

[0010] Based on the assembly status, a corresponding speed control strategy is selected, and the current speed of the motor is adjusted using the speed control strategy.

[0011] Optionally, the step of determining the assembly state of the screw to be assembled based on the standard assembly tachometer, the current torque, and the current remaining thread length includes:

[0012] The standard torque variation threshold and standard length variation threshold within a unit assembly time period are obtained based on the standard assembly tachometer.

[0013] Plot a torque change curve based on the current torque, and determine the torque change rate within the corresponding unit assembly time period based on the torque change curve;

[0014] A length variation curve is plotted based on the current remaining thread length, and the length variation rate within the corresponding unit assembly time period is determined based on the length variation curve.

[0015] The assembly state of the screw to be assembled is determined based on the torque change rate, the standard torque change threshold, the length change rate, and the standard length change threshold.

[0016] Optionally, the step of determining the assembly state of the screw to be assembled based on the torque change rate, the standard torque change threshold, the length change rate, and the standard length change threshold includes:

[0017] When the torque change rate is lower than the standard torque change threshold and the length change rate is higher than the standard length change threshold, the assembly state of the screw to be assembled is determined to be an abnormal assembly state.

[0018] Accordingly, the step of selecting a corresponding speed control strategy based on the assembly state and adjusting the current speed of the motor through the speed control strategy includes:

[0019] When the assembly state is an abnormal assembly state, the force information of the bit is obtained;

[0020] The corresponding speed control strategy is selected based on the force information of the bit, and the current speed of the motor is adjusted through the speed control strategy.

[0021] Optionally, after the step of selecting a corresponding speed control strategy based on the assembly state and adjusting the current speed of the motor through the speed control strategy, the method further includes:

[0022] Obtain the historical assembly logs corresponding to the assembly process flow;

[0023] The operating status of the motor is determined based on the historical assembly log, the torque variation curve, and the length variation curve.

[0024] A corresponding maintenance strategy is generated based on the described working status.

[0025] Optionally, before the step of acquiring the current torque of the motor and the current remaining thread length of the screw to be assembled, the method further includes:

[0026] The force change of the bit is collected, and when the force change meets the first preset force change condition, the motor is controlled to rotate forward according to the first preset rotation stroke;

[0027] When the force change condition meets the second preset force change condition, the motor is controlled to reverse by the second preset rotation stroke.

[0028] Optionally, before the step of controlling the motor to reverse by a second preset rotational stroke when the force change condition meets the second preset force change condition, the method further includes:

[0029] The nut structure of the screw to be assembled is determined according to the assembly process flow.

[0030] The second preset rotation stroke is adjusted based on the nut structure;

[0031] Accordingly, the step of controlling the motor to reverse by a second preset rotational stroke when the force change condition meets the second preset force change condition includes:

[0032] When the force change condition meets the second preset force change condition, the motor is controlled to reverse by the adjusted second preset rotation stroke.

[0033] Optionally, before the step of acquiring the current torque of the motor and the current remaining thread length of the screw to be assembled, the method further includes:

[0034] The assembly angle of the screw to be assembled is determined according to the assembly process flow.

[0035] The standard force point information of the handpiece is determined based on the assembly angle.

[0036] Obtain the current force point information of the handpiece, and determine whether the assembly posture requirements are met based on the current force point information and the standard force point information;

[0037] If so, then perform the steps of collecting the current torque of the motor and the current remaining thread length of the screw to be assembled.

[0038] Furthermore, to achieve the above objectives, the present invention also proposes a motor speed control device, the device comprising:

[0039] The process acquisition module is used to acquire the assembly process flow and determine the standard assembly speed table based on the assembly process flow. The standard assembly speed table stores a mapping relationship table between the remaining thread length of the screw to be assembled and the real-time torque of the motor at each assembly moment.

[0040] The data acquisition module is used to acquire the current torque of the motor and the current remaining thread length of the screw to be assembled;

[0041] The status determination module is used to determine the assembly status of the screw to be assembled based on the standard assembly tachometer, the current torque, and the current remaining thread length.

[0042] The speed adjustment module is used to select a corresponding speed control strategy based on the assembly state, and adjust the current speed of the motor through the speed control strategy.

[0043] Furthermore, to achieve the above objectives, the present invention also proposes a motor speed control device, the device comprising: a memory, a processor, and a motor speed control program stored in the memory and executable on the processor, the motor speed control program being configured to implement the steps of the motor speed control method described above.

[0044] In addition, to achieve the above objectives, the present invention also proposes a storage medium storing a motor speed control program, wherein the motor speed control program, when executed by a processor, implements the steps of the motor speed control method described above.

[0045] This invention acquires the assembly process flow and determines a standard assembly tachometer based on it. The standard tachometer stores a mapping relationship between the remaining thread length of the screw to be assembled and the real-time torque of the motor at each assembly moment. It collects the current torque of the motor and the current remaining thread length of the screw to be assembled. Based on the standard tachometer, the current torque, and the current remaining thread length, it determines the assembly state of the screw to be assembled. Based on the assembly state, it selects a corresponding speed control strategy and adjusts the current speed of the motor using this strategy. Because this invention compares the current torque of the motor and the current remaining thread length of the screw to be assembled with the standard tachometer, it can determine the current assembly state of the screw to be assembled and adjust the motor speed accordingly. Compared to existing motors that operate at a preset speed, this invention adjusts the motor speed based on the current remaining thread length, increasing service life and improving the accuracy of torque control. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the structure of the motor speed control device in the hardware operating environment involved in the embodiments of the present invention;

[0047] Figure 2 This is a flowchart illustrating the first embodiment of the motor speed control method of the present invention;

[0048] Figure 3This is a flowchart illustrating the second embodiment of the motor speed control method of the present invention;

[0049] Figure 4 This is a flowchart illustrating the third embodiment of the motor speed control method of the present invention;

[0050] Figure 5 This is a structural block diagram of the first embodiment of the motor speed control device of the present invention.

[0051] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0052] It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0053] Reference Figure 1 , Figure 1 This is a schematic diagram of the structure of a motor speed control device in the hardware operating environment involved in the embodiments of the present invention.

[0054] like Figure 1 As shown, the motor speed control device may include: a processor 1001, such as a central processing unit (CPU), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. The communication bus 1002 is used to enable communication between these components. The user interface 1003 may include a display screen or an input unit such as a keyboard; optionally, the user interface 1003 may also include a standard wired interface or a wireless interface. The network interface 1004 may optionally include a standard wired interface or a wireless interface (such as a Wireless-Fidelity (Wi-Fi) interface). The memory 1005 may be high-speed random access memory (RAM) or stable non-volatile memory (NVM), such as a disk storage device. Optionally, the memory 1005 may also be a storage device independent of the aforementioned processor 1001.

[0055] Those skilled in the art will understand that Figure 1 The structure shown does not constitute a limitation on the motor speed control device and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0056] like Figure 1As shown, the memory 1005, which serves as a storage medium, may include an operating system, a network communication module, a user interface module, and a motor speed control program.

[0057] exist Figure 1 In the motor speed control device shown, the network interface 1004 is mainly used for data communication with the network server; the user interface 1003 is mainly used for data interaction with the user; the processor 1001 and the memory 1005 in the motor speed control device of the present invention can be set in the motor speed control device, and the motor speed control device calls the motor speed control program stored in the memory 1005 through the processor 1001 and executes the motor speed control method provided in the embodiment of the present invention.

[0058] This invention provides a method for controlling motor speed, as described in the following embodiments. Figure 2 , Figure 2 This is a flowchart illustrating the first embodiment of the motor speed control method of the present invention.

[0059] In this embodiment, the motor speed control method includes the following steps:

[0060] Step S10: Obtain the assembly process flow and determine the standard assembly speed table according to the assembly process flow. The standard assembly speed table stores a mapping relationship table between the remaining thread length of the screw to be assembled and the real-time torque of the motor at each assembly time.

[0061] It should be noted that the method in this embodiment can be applied to scenarios where the speed of an electric screwdriver motor needs to be adjusted, or other scenarios where the motor speed needs to be controlled. The executing entity in this embodiment can be a motor speed control device with data processing, network communication, and program execution functions, such as an electric screwdriver, or other devices capable of achieving the same or similar functions. This embodiment and the following embodiments will be specifically described using the aforementioned motor speed control device (hereinafter referred to as the device).

[0062] Understandably, the above assembly process can include the entire assembly process performed by the workers. For example, it may include: materials to be assembled, screws to be assembled, and assembly positions. The above assembly process can be obtained according to the worker's job position. For example, when a worker needs to assemble a wooden table, the above equipment can first obtain the worker's job position information, which can be obtained by inputting the worker's employee number. Based on the job position information, it can determine that the object to be assembled is a wooden table, and can simultaneously obtain the overall structure of the wooden table, the assembly sequence, the positions to be assembled, etc. It can also obtain the corresponding screws to be assembled for the assembly positions, thereby improving the efficiency and accuracy of the assembly.

[0063] It should be understood that the above assembly process may also include a standard tachometer. During assembly, after determining the screw to be assembled, the above equipment can obtain the corresponding standard tachometer. The standard tachometer stores a mapping table between the remaining thread length of the screw to be assembled and the real-time torque of the motor at each time.

[0064] Understandably, the aforementioned remaining thread length can be the length that the screw to be assembled still needs to be assembled. At the same time, the aforementioned standard tachometer can be obtained in advance by the motor manufacturer through testing based on different screws and different materials to be assembled. The aforementioned real-time torque can be the appropriate torque required by the motor at the remaining thread length. Different remaining thread lengths require different real-time torques. For example, the longer the remaining thread length, the smaller the torque can be.

[0065] In practice, the aforementioned equipment can acquire the assembly process flow and determine the standard assembly tachometer based on the assembly process flow.

[0066] Step S20: Collect the current torque of the motor and the current remaining thread length of the screw to be assembled.

[0067] It should be noted that the current torque mentioned above can be the torque of the motor at the current moment. The device may be equipped with a tachometer, which can be obtained by processing the digital pulse signal through the tachometer via a speed sensor, or it can be obtained through other means. This embodiment does not impose any restrictions.

[0068] It is understood that the current remaining thread length of the screw to be assembled can be the length that the screw to be assembled still needs to be assembled at the current moment. In this embodiment, an infrared ranging device can be set on the above-mentioned equipment. The current remaining thread length can be obtained by measuring the distance between the infrared ranging device and the panel of the object to be assembled and subtracting the distance between the top of the bit of the equipment and the infrared ranging device. Other methods can also be used to obtain the current remaining thread length, and this embodiment does not limit them.

[0069] Furthermore, considering that incorrect operator posture during assembly can easily lead to tilting of the assembly angle of the screw to be assembled, resulting in assembly failure, the following steps are included before step S20:

[0070] Step S11: Determine the assembly angle of the screw to be assembled according to the assembly process flow.

[0071] It should be noted that the above assembly angle can be based on the angle between the surface of the object to be assembled and the screw to be assembled. Since the assembly angle may be different at different assembly positions, the above assembly process can also store the assembly angle corresponding to the screw to be assembled at a certain assembly position.

[0072] Step S12: Determine the standard force point information of the handpiece based on the assembly angle.

[0073] Understandably, the aforementioned handheld part can be the part used by the worker to grip the aforementioned equipment. The aforementioned equipment can be pre-divided into several force points in the handheld part. The aforementioned force points can be the positions where the worker contacts the hand during assembly. At the same time, a force acquisition device can be installed in the aforementioned force points, which can be a sensor or other device used to collect the surface force conditions.

[0074] It should be understood that since the hand postures required by the workers are different for different assembly angles, the above-mentioned equipment can select the corresponding standard force points from several force points according to the assembly angle, and at the same time obtain the standard force magnitude of each standard force point to generate the above-mentioned standard force point information.

[0075] Step S13: Obtain the current force point information of the handheld part, and determine whether the assembly posture requirements are met based on the current force point information and the standard force point information.

[0076] It should be noted that the above-mentioned current force point information can be the current force point of the handpiece contacting the worker's hand, as well as the current force magnitude corresponding to each current force point.

[0077] It should be emphasized that, since there may be multiple standard force point information for the same assembly angle, that is, the assembly angle of the screw to be assembled can meet the requirements by the worker adopting different assembly postures, there may be multiple standard force point information corresponding to the same assembly angle.

[0078] It should also be emphasized that when the current force point information is the same as the standard force point information, the above equipment can determine that the operator's operating posture meets the required assembly posture requirements, thereby ensuring that the assembly angle is correct and allowing assembly to proceed. At the same time, the standard force magnitude corresponding to the standard force point can be a force range, that is, if the current force magnitude is within the force range, the above equipment can also determine that the operator's operating posture meets the required assembly posture requirements.

[0079] Step S14: If yes, then perform the step of collecting the current torque of the motor and the current remaining thread length of the screw to be assembled.

[0080] It should be noted that if the above equipment determines that the operator's operating posture does not meet the requirements, the equipment can stop the motor from rotating and at the same time provide a light prompt at the force point that does not meet the requirements, indicating to the operator which force point does not meet the requirements, and turn off the light after the point meets the requirements.

[0081] In practical implementation, the above-mentioned equipment can determine the assembly angle of the screw to be assembled according to the assembly process flow, and determine the standard force point information of the hand-held part according to the assembly angle. Then, it can obtain the current force point information of the hand-held part. When the current force point information is the same as the standard force point information, it is determined that the operator's operating posture meets the assembly posture requirements, and then the motor is allowed to rotate. At the same time, the current torque of the motor and the current remaining thread length of the screw to be assembled are collected.

[0082] Step S30: Determine the assembly state of the screw to be assembled based on the standard assembly tachometer, the current torque, and the current remaining thread length.

[0083] It is understood that the above assembly states can be divided according to the assembly progress, such as the initial state, the rotation state, and the pre-tightening state. The initial state can be the state when the screw to be assembled begins to be assembled until the current remaining thread length is the first thread length. The rotation state can be the state when the current remaining thread length is from the first thread length to the second thread length. The pre-tightening state can be the state from the second thread length to the tightening completion. The first thread length and the second thread length can be set according to the actual situation. At the same time, the specific division of the above assembly states is not limited in this embodiment.

[0084] In practice, the above-mentioned equipment can determine the assembly state of the screw to be assembled based on the standard assembly state tachometer, the current torque, and the current remaining thread length.

[0085] Step S40: Select the corresponding speed control strategy based on the assembly state, and adjust the current speed of the motor through the speed control strategy.

[0086] It should be understood that different assembly states correspond to different rotational speeds, and therefore the above-mentioned speed control strategies may differ. For example, the rotational speed can be increased in the initial state to speed up assembly efficiency, while the rotational speed can be reduced in the pre-tightening state to extend the motor's service life.

[0087] It should be noted that the specific speed adjustment amount in the above speed control strategy can be obtained in advance through experiments. The speed control strategy corresponding to each assembly state can be stored in the cloud. The above equipment can obtain the corresponding speed control strategy from the cloud. At the same time, in order to improve control efficiency, the above speed control strategy can be saved locally.

[0088] It should be emphasized that the specific speed control strategy can be set according to the actual situation, and this embodiment does not impose any restrictions. It should also be emphasized that the above-mentioned device can also collect the assembly results of the motor after adjustment according to the speed control strategy. If the assembly results are not ideal, the speed control strategy can be adjusted according to the assembly process.

[0089] In practical implementation, the above-mentioned equipment can select the corresponding speed control strategy based on the assembly state, and adjust the current speed of the motor through the speed control strategy.

[0090] In this embodiment, the aforementioned device can acquire the assembly process flow and determine a standard assembly tachometer based on the assembly process flow; determine the assembly angle of the screw to be assembled based on the assembly process flow, and determine the standard force point information of the handheld part based on the assembly angle, and then obtain the current force point information of the handheld part. When the current force point information is the same as the standard force point information, it is determined that the operator's operating posture meets the assembly posture requirements, and thus the motor is allowed to rotate. At the same time, the current torque of the motor and the current remaining thread length of the screw to be assembled are collected; the assembly state of the screw to be assembled is determined based on the standard assembly state tachometer, the current torque, and the current remaining thread length; a corresponding speed control strategy is selected based on the assembly state, and the current speed of the motor is adjusted through the speed control strategy. Since this embodiment compares the current torque of the motor and the current remaining thread length of the screw to be assembled with the standard assembly tachometer, it can determine the current assembly state of the screw to be assembled and adjust the motor speed based on the current assembly state. Compared with the existing motors that operate at a preset speed, this embodiment can adjust the motor speed based on the current remaining thread length, increasing the service life.

[0091] refer to Figure 3 , Figure 3 This is a flowchart illustrating the second embodiment of the motor speed control method of the present invention.

[0092] Considering that directly comparing the current torque and the current remaining thread length at each moment is inefficient and slow, based on the above embodiments, such as Figure 3 As shown, in this embodiment, step S30 includes:

[0093] Step S31: Obtain the standard torque change threshold and standard length change threshold within a unit assembly time period based on the standard assembly tachometer.

[0094] It should be noted that the above-mentioned unit assembly time period can be any time period during the assembly process. The above-mentioned unit time period can be 0.5 seconds, 1 second, or other time periods of duration, which can be set according to the actual situation. It is understood that the shorter the unit time period, the more sensitive the above-mentioned equipment is to the recognition of the assembly status.

[0095] It should be understood that the above-mentioned equipment can plot a real-time torque change curve based on a standard assembly tachometer, and determine the slope of the real-time torque change curve within a unit assembly time period based on the real-time torque change curve, using the slope as the standard torque change threshold. At the same time, it can plot a remaining thread length change curve based on a standard assembly tachometer, and determine the slope of the remaining thread length change curve within a unit assembly time period based on the remaining thread length change curve, using the slope as the standard length change threshold.

[0096] In practical implementation, the above-mentioned equipment can obtain the standard torque change threshold and standard length change threshold within a unit assembly time period based on the standard assembly tachometer.

[0097] Step S32: Plot the torque change curve based on the current torque, and determine the torque change rate within the corresponding unit assembly time period based on the torque change curve.

[0098] Step S33: Draw a length change curve based on the current remaining thread length, and determine the length change rate within the corresponding unit assembly time period based on the length change curve.

[0099] Step S34: Determine the assembly state of the screw to be assembled based on the torque change rate, the standard torque change threshold, the length change rate, and the standard length change threshold.

[0100] It should be noted that when determining the torque change rate and length change rate within a unit assembly time period using the above-mentioned equipment, the unit assembly time periods corresponding to the same values ​​can be iterated through the above-mentioned standard torque change threshold and standard length change threshold based on the torque change rate and length change rate, and the corresponding assembly state can be determined based on the above-mentioned unit assembly time periods.

[0101] In practical implementation, the above-mentioned device can draw a torque change curve based on the current torque, and determine the torque change rate within a unit assembly time period based on the torque change curve. At the same time, it can draw a length change curve based on the current remaining thread length, and determine the length change rate within a unit assembly time period based on the length change curve. Then, it can iterate through the standard torque change threshold based on the torque change rate, and through the standard length change threshold based on the length change rate. Based on the determined unit assembly time period, it can obtain the assembly state of the screw to be assembled, thereby improving the speed of determining the assembly state.

[0102] Furthermore, considering that during the assembly process, the groove in the nut may be worn flat, or the thread in the screw hole at the assembly position may be worn flat, making it impossible for the worker to continue the assembly, in this embodiment, the above step S34 includes: when the torque change rate is lower than the standard torque change threshold and the length change rate is higher than the standard length change threshold, the assembly state of the screw to be assembled is determined to be an abnormal assembly state.

[0103] It should be noted that the above-mentioned abnormal assembly state can be the state in which the groove in the nut is ground flat and the thread in the screw hole at the assembly position is ground flat. Since the resistance of the motor is reduced when the assembly state is in an abnormal assembly state, the current torque is reduced, and the current remaining thread length decreases or even remains unchanged. Therefore, when the torque change rate is lower than the standard torque change threshold and the length change rate is higher than the standard length change threshold, the assembly state of the screw to be assembled can be determined to be an abnormal assembly state.

[0104] Accordingly, the step of selecting a corresponding speed control strategy based on the assembly state and adjusting the current speed of the motor through the speed control strategy includes:

[0105] When the assembly state is an abnormal assembly state, the force information of the bit is obtained; the corresponding speed control strategy is selected according to the force information of the bit, and the current speed of the motor is adjusted through the speed control strategy.

[0106] Understandably, since the groove in the nut is ground flat, the force on the bit is not the same as the force on the bit when the thread in the screw hole at the assembly position is ground flat. Therefore, the force information of the bit can be used to determine which abnormal assembly state it is in.

[0107] Specifically, when the groove in the nut is about to be ground flat, the bit experiences a greater force in the rotation direction; when the thread in the screw hole at the assembly position is ground flat, the bit experiences a greater force in the bit travel direction.

[0108] It should be understood that a sensor can be installed at the bit in the aforementioned device. The sensor can obtain the magnitude of the force at various angles of the bit, and thus generate force information.

[0109] It is important to emphasize that if the groove in the nut is about to be worn flat, continuing to rotate the bit may cause the groove to be completely worn flat, making it impossible to assemble the screw or remove it. Therefore, the corresponding speed control strategy could be to immediately stop the motor from rotating or reduce the speed to the minimum. If the groove is not worn flat after the speed is reduced to the minimum, the rotation can continue at the minimum speed. If the groove is worn flat, the rotation can be stopped immediately and the motor can be reversed to try to remove the screw.

[0110] When the thread in the screw hole at the aforementioned assembly position is about to be worn down, if the bit continues to rotate, the thread in the screw hole at the assembly position may not be able to lock the screw to be assembled. This may eventually require re-operation of the screw hole at the assembly position to generate the thread, increasing the workload. Therefore, the corresponding speed control strategy mentioned above can be to immediately stop the motor from continuing to rotate, or to immediately control the motor to reverse and remove the screw to be assembled.

[0111] In practical implementation, the above-mentioned equipment can determine that the assembly state of the screw to be assembled is an abnormal assembly state when the torque change rate is lower than the standard torque change threshold and the length change rate is higher than the standard length change threshold. It can also determine the specific abnormal assembly state based on the force information of the bit, and finally select the corresponding speed control strategy based on the force information. The current speed of the motor is controlled by the speed control strategy, which can provide early warning of the abnormal assembly situation that is about to occur and improve assembly efficiency.

[0112] To facilitate subsequent motor maintenance and further increase its service life, this embodiment further includes the following step after step S40:

[0113] Step S41: Obtain the historical assembly log corresponding to the assembly process flow.

[0114] It should be noted that when the above-mentioned equipment completes an assembly, the assembly log can be uploaded to the cloud. The assembly log may include information such as the change of motor torque at each moment during the assembly, the change of the current remaining thread length at each moment, and the corresponding change of speed.

[0115] Step S42: Determine the operating status of the motor based on the historical assembly log, the torque change curve, and the length change curve;

[0116] It is understandable that the torque and length variation curves mentioned above are the curves for this assembly. If the torque and length variation curves deviate significantly from the curves in the historical assembly log, it can be determined that the motor is in an abnormal state and requires immediate maintenance. If the torque and length variation curves deviate slightly from the curves in the historical assembly log, it can be determined that the motor is in a somewhat abnormal state, but does not require immediate maintenance. It can still be used for a period of time, and the staff can arrange their own maintenance schedule according to the available time.

[0117] Step S43: Generate a corresponding maintenance strategy based on the working status.

[0118] It should be understood that the above-mentioned equipment can also determine the location of possible internal faults based on historical assembly logs, torque change curves, and length change curves. For example, if the torque change curve is normal but the length change curve is abnormal, it may be due to internal shaft wear or other reasons. Therefore, the above-mentioned working status may include specific abnormal causes.

[0119] It is understood that the above maintenance strategy can be a unified repair or maintenance strategy generated for the corresponding working status, and can be sent to the staff's mobile devices for display. For example, it can be based on historical assembly logs to show that staff perform maintenance in a timely manner according to the frequency of use, thereby further improving the service life. The specific maintenance strategy mentioned above is not limited in this embodiment.

[0120] In practice, the aforementioned equipment can first obtain the historical assembly logs corresponding to the assembly process flow, and determine the working status of the motor based on the historical assembly logs, torque change curves, and length change curves, and then generate corresponding maintenance strategies based on the working status.

[0121] In this embodiment, the aforementioned device can plot a torque change curve based on the current torque, determine the torque change rate within a unit assembly time period based on the torque change curve, and simultaneously plot a length change curve based on the current remaining thread length, determine the length change rate within a unit assembly time period based on the length change curve, and then iterate through the standard torque change threshold based on the torque change rate and the standard length change threshold based on the length change rate. Based on the determined unit assembly time period, the assembly state of the screw to be assembled is obtained, thereby improving the speed of determining the assembly state. Furthermore, when the torque change rate is lower than the standard torque change threshold and the length change rate is higher than the standard length change threshold, the assembly state of the screw to be assembled is determined as an abnormal assembly state. The specific abnormal assembly state is determined based on the force information of the bit, and finally, a corresponding speed control strategy is selected based on the force information to control the current speed of the motor, thereby providing early warning of impending abnormal assembly situations and improving assembly efficiency. This embodiment can also obtain historical assembly logs corresponding to the assembly process flow, determine the motor's working state based on the historical assembly logs, torque change curve, and length change curve, and then generate corresponding maintenance strategies based on the working state, further improving service life.

[0122] refer to Figure 4 , Figure 4 This is a flowchart illustrating the third embodiment of the motor speed control method of the present invention.

[0123] Considering that before assembly, workers need to match the nut of the screw to be assembled with the screwdriver bit, but manual matching may result in unsuccessful nut matching, leading to the screwdriver bit separating from the nut during assembly, resulting in low assembly efficiency. Based on the above embodiments, as Figure 4 As shown, in this embodiment, before step S20, the following steps are also included:

[0124] Step S201: Collect the force change of the bit, and when the force change meets the first preset force change condition, control the motor to rotate forward according to the first preset rotation stroke.

[0125] It should be noted that when the worker brings the nut of the screw to be assembled into contact with the bit, the force on the bit can change from no force to a certain supporting force. The first preset force change condition is the condition that can be achieved when the nut and bit come into contact. Then the device can control the motor to rotate in the forward direction to complete the nut insertion process.

[0126] It is understood that the aforementioned first preset rotation stroke can be set according to the distance between the two grooves of the nut, and this embodiment does not impose any restrictions.

[0127] As another implementation of this embodiment, the first preset rotation stroke can also be obtained according to the assembly process flow, and the nut structure of each screw to be assembled is stored according to the assembly process flow.

[0128] Step S202: When the force change condition meets the second preset force change condition, control the motor to reverse by the second preset rotation stroke.

[0129] It should be understood that when the aforementioned bit matches the groove of the nut, due to inertia, the bit may have excessive rotational travel, thus requiring the motor to be controlled to reverse.

[0130] It should be noted that the above-mentioned second preset force change condition can be the condition that can be achieved when the above-mentioned nut groove matches the bit, and the above-mentioned second preset stroke can be set according to the actual situation.

[0131] In its specific implementation, the device can collect the force changes of the bit, and when the force changes meet the first preset force change condition, control the motor to rotate forward according to the first preset rotation stroke, and when the force changes meet the second preset force change condition, control the motor to rotate backward according to the second preset rotation stroke.

[0132] Furthermore, considering that different nuts correspond to different grooves, and in order to match the second preset rotation stroke with the groove, in this embodiment, before step S202 above, the following steps are also included:

[0133] The nut structure of the screw to be assembled is determined according to the assembly process flow; the second preset rotation stroke is adjusted based on the nut structure; correspondingly, the step of controlling the motor to reverse with the second preset rotation stroke when the force change condition meets the second preset force change condition includes: controlling the motor to reverse with the adjusted second preset rotation stroke when the force change condition meets the second preset force change condition.

[0134] It should be noted that the above adjustment amount can be set according to the specific nut structure.

[0135] In this embodiment, the device described above can collect the force changes of the bit, and when the force changes meet the first preset force change condition, control the motor to rotate forward according to the first preset rotation stroke. When the force changes meet the second preset force change condition, control the motor to rotate backward according to the second preset rotation stroke. At the same time, the second preset rotation stroke can be adjusted according to different nut structures to improve the tightness between the bit and the nut and improve the assembly success rate.

[0136] Furthermore, this embodiment of the invention also proposes a storage medium storing a motor speed control program, which, when executed by a processor, implements the steps of the motor speed control method described above.

[0137] In addition, refer to Figure 5 , Figure 5 This is a structural block diagram of the first embodiment of the motor speed control device of the present invention. The present invention also proposes a motor speed control device, which includes:

[0138] The process acquisition module 501 is used to acquire the assembly process flow and determine the standard assembly speed table according to the assembly process flow. The standard assembly speed table stores a mapping relationship table between the remaining thread length of the screw to be assembled and the real-time torque of the motor at each assembly moment.

[0139] The data acquisition module 502 is used to acquire the current torque of the motor and the current remaining thread length of the screw to be assembled;

[0140] The state determination module 503 is used to determine the assembly state of the screw to be assembled based on the standard assembly tachometer, the current torque, and the current remaining thread length.

[0141] The speed adjustment module 504 is used to select a corresponding speed control strategy based on the assembly state, and adjust the current speed of the motor through the speed control strategy.

[0142] In this embodiment, the aforementioned device can acquire the assembly process flow and determine a standard assembly tachometer based on the assembly process flow; determine the assembly angle of the screw to be assembled based on the assembly process flow, and determine the standard force point information of the handheld part based on the assembly angle, and then obtain the current force point information of the handheld part. When the current force point information is the same as the standard force point information, it is determined that the operator's operating posture meets the assembly posture requirements, and thus the motor is allowed to rotate. At the same time, the current torque of the motor and the current remaining thread length of the screw to be assembled are collected; the assembly state of the screw to be assembled is determined based on the standard assembly state tachometer, the current torque, and the current remaining thread length; a corresponding speed control strategy is selected based on the assembly state, and the current speed of the motor is adjusted through the speed control strategy. Since this embodiment compares the current torque of the motor and the current remaining thread length of the screw to be assembled with the standard assembly tachometer, it can determine the current assembly state of the screw to be assembled and adjust the motor speed based on the current assembly state. Compared with the existing motors that operate at a preset speed, this embodiment can adjust the motor speed based on the current remaining thread length, increasing the service life.

[0143] Other embodiments or specific implementations of the motor speed control device of the present invention can be referred to the above-described method embodiments, and will not be repeated here.

[0144] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0145] The sequence numbers of the above embodiments of the present invention are merely for description and do not represent the superiority or inferiority of the embodiments. Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as read-only memory / random access memory, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0146] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A method for controlling motor speed, characterized in that, The method includes the following steps: Obtain the assembly process flow and determine a standard assembly speed table based on the assembly process flow. The standard assembly speed table stores a mapping relationship table between the remaining thread length of the screw to be assembled and the real-time torque of the motor at each assembly time. The remaining thread length is the length that the screw to be assembled still needs to be assembled. Collect the current torque of the motor and the current remaining thread length of the screw to be assembled; The assembly state of the screw to be assembled is determined based on the standard assembly tachometer, the current torque, and the current remaining thread length. The assembly state includes an initial state, a rotational state, and a pre-tightening state. The initial state is the state when the screw to be assembled begins to be assembled until the current remaining thread length is the first thread length. The rotational state is the state when the current remaining thread length is between the first thread length and the second thread length. The pre-tightening state is the state from the second thread length to the state where tightening is complete. Based on the assembly status, a corresponding speed control strategy is selected, and the current speed of the motor is adjusted through the speed control strategy. The step of determining the assembly state of the screw to be assembled based on the standard assembly tachometer, the current torque, and the current remaining thread length includes: The standard torque change threshold and standard length change threshold within a unit assembly time period are obtained based on the standard assembly tachometer, where the unit assembly time period is the time period during the assembly process. Plot a torque change curve based on the current torque, and determine the torque change rate within the corresponding unit assembly time period based on the torque change curve; A length variation curve is plotted based on the current remaining thread length, and the length variation rate within the corresponding unit assembly time period is determined based on the length variation curve. The assembly state of the screw to be assembled is determined based on the torque change rate, the standard torque change threshold, the length change rate, and the standard length change threshold. The standard torque change threshold is the slope of the torque change curve within the unit assembly time period, and the standard length change threshold is the slope of the length change curve within the unit assembly time period. The step of determining the assembly state of the screw to be assembled based on the torque change rate, the standard torque change threshold, the length change rate, and the standard length change threshold includes: When the torque change rate is lower than the standard torque change threshold and the length change rate is higher than the standard length change threshold, the assembly state of the screw to be assembled is determined to be an abnormal assembly state. Accordingly, the step of selecting a corresponding speed control strategy based on the assembly state and adjusting the current speed of the motor through the speed control strategy includes: When the assembly state is an abnormal assembly state, the force information of the bit is obtained, and the force information is used to determine whether the groove in the nut is worn flat or the thread is worn flat. The corresponding speed control strategy is selected based on the force information of the bit, and the current speed of the motor is adjusted through the speed control strategy. Specifically, when the groove in the nut shows a tendency to be worn down, the speed control strategy is to immediately stop the motor rotation, or reduce the speed to the minimum speed, and after the minimum speed, if the groove does not show a tendency to be worn down, rotate at the minimum speed; if the groove shows a tendency to be worn down, stop the motor rotation and control the motor to reverse; when the thread shows a tendency to be worn down, the speed control strategy is to stop the motor rotation or control the motor to reverse.

2. The motor speed control method as described in claim 1, characterized in that, After the step of selecting a corresponding speed control strategy based on the assembly state and adjusting the current speed of the motor using the speed control strategy, the method further includes: Obtain the historical assembly logs corresponding to the assembly process flow; The operating status of the motor is determined based on the historical assembly log, the torque variation curve, and the length variation curve. A corresponding maintenance strategy is generated based on the described working status.

3. The motor speed control method as described in claim 1 or 2, characterized in that, Before the step of acquiring the current torque of the motor and the current remaining thread length of the screw to be assembled, the method further includes: The force change of the bit is collected, and when the force change meets the first preset force change condition, the motor is controlled to rotate forward according to the first preset rotation stroke; When the force change condition meets the second preset force change condition, the motor is controlled to reverse by the second preset rotation stroke.

4. The motor speed control method as described in claim 3, characterized in that, Before the step of controlling the motor to reverse by a second preset rotational stroke when the force change condition meets the second preset force change condition, the method further includes: The nut structure of the screw to be assembled is determined according to the assembly process flow. The second preset rotation stroke is adjusted based on the nut structure; Accordingly, the step of controlling the motor to reverse by a second preset rotational stroke when the force change condition meets the second preset force change condition includes: When the force change condition meets the second preset force change condition, the motor is controlled to reverse by the adjusted second preset rotation stroke.

5. The motor speed control method as described in claim 1, characterized in that, Before the step of acquiring the current torque of the motor and the current remaining thread length of the screw to be assembled, the method further includes: The assembly angle of the screw to be assembled is determined according to the assembly process flow. The standard force point information of the handpiece is determined based on the assembly angle. Obtain the current force point information of the handpiece, and determine whether the assembly posture requirements are met based on the current force point information and the standard force point information; If so, then perform the steps of collecting the current torque of the motor and the current remaining thread length of the screw to be assembled.

6. A motor speed control device, characterized in that, The device includes: The process acquisition module is used to acquire the assembly process flow and determine the standard assembly speed table based on the assembly process flow. The standard assembly speed table stores a mapping relationship table between the remaining thread length of the screw to be assembled and the real-time torque of the motor at each assembly time. The remaining thread length is the length that the screw to be assembled still needs to be assembled. The data acquisition module is used to acquire the current torque of the motor and the current remaining thread length of the screw to be assembled; The state determination module is used to determine the assembly state of the screw to be assembled based on the standard assembly tachometer, the current torque, and the current remaining thread length. The assembly state includes an initial state, a rotational state, and a pre-tightening state. The initial state is the state when the screw to be assembled begins to be assembled until the current remaining thread length is the first thread length. The rotational state is the state when the current remaining thread length is between the first thread length and the second thread length. The pre-tightening state is the state from the second thread length to the state where tightening is complete. The speed adjustment module is used to select a corresponding speed control strategy based on the assembly state, and adjust the current speed of the motor through the speed control strategy; The state determination module is further configured to obtain a standard torque change threshold and a standard length change threshold within a unit assembly time period based on the standard assembly tachometer, wherein the unit assembly time period is a time period during the assembly process; plot a torque change curve based on the current torque, and determine the torque change rate within the corresponding unit assembly time period based on the torque change curve; plot a length change curve based on the current remaining thread length, and determine the length change rate within the corresponding unit assembly time period based on the length change curve; and determine the assembly state of the screw to be assembled based on the torque change rate, the standard torque change threshold, the length change rate, and the standard length change threshold, wherein the standard torque change threshold is the slope of the torque change curve within the unit assembly time period, and the standard length change threshold is the slope of the length change curve within the unit assembly time period. The state determination module is further configured to determine that the assembly state of the screw to be assembled is an abnormal assembly state when the torque change rate is lower than the standard torque change threshold and the length change rate is higher than the standard length change threshold. The speed adjustment module is further configured to acquire the force information of the bit when the assembly state is an abnormal assembly state. The force information is used to determine whether the groove in the nut is worn flat or the thread is worn flat. Based on the force information of the bit, a corresponding speed control strategy is selected, and the current speed of the motor is adjusted using the speed control strategy. Specifically, when the groove in the nut shows a tendency to be worn flat, the speed control strategy is to immediately stop the motor rotation or reduce the speed to a minimum speed. After the minimum speed, if the groove does not show a tendency to be worn flat, the motor rotates at the minimum speed. If the groove shows a tendency to be worn flat, the motor rotation is stopped, and the motor is reversed. When the thread shows a tendency to be worn flat, the speed control strategy is to stop the motor rotation or reverse the motor.

7. A motor speed control device, characterized in that, The device includes: a memory, a processor, and a motor speed control program stored in the memory and executable on the processor, the motor speed control program being configured to implement the steps of the motor speed control method as described in any one of claims 1 to 5.

8. A storage medium, characterized in that, The storage medium stores a motor speed control program, which, when executed by a processor, implements the steps of the motor speed control method as described in any one of claims 1 to 5.

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