Torque closed-loop-based electric screwdriver control method, device, equipment and storage medium

Abstract

The application discloses a torque closed-loop-based electric wrench control method and device, equipment and storage medium, the method comprises the following steps: controlling the electric wrench to run from the initial first preset position to the second preset position; after the electric wrench reaches the second preset position, controlling the electric wrench to run at a first preset speed; when the electric wrench runs at the first preset speed, collecting the torque feedback value of the torque sensor in real time; when the torque feedback value is greater than the first preset torque, inputting the torque feedback value and the second preset torque into the torque control loop; when the torque feedback value is equal to the second preset torque, controlling the electric wrench to stop tightening. The high-speed section and the low-speed section based on the position control mode are adopted, the proportion of the low-speed section distance in the whole stroke distance is adjusted, the torque feedback value is collected, the second preset torque and the torque feedback value are input into the torque control loop, and the electric wrench is controlled to run according to the driving current output by the torque control loop, so that the torque rapid following can be met, and the overshoot generated by the torque controller can be inhibited.

Description

Technical Field

[0001] This application relates to the field of automatic control technology, and in particular to an electric screwdriver control method, apparatus, device and storage medium based on torque closed loop. Background Technology

[0002] Before tightening with an electric screwdriver, the current needs to be calibrated using a torque tester to obtain the conversion coefficient between current and output torque. The target torque is then multiplied by the conversion coefficient to obtain the required control current. The tightening process uses a two-stage speed based on a speed mode. A higher speed is used when the screw is being threaded, and the speed is reduced to a lower speed as the screw tightens. If the torque sensor feedback value is less than the target torque, the screw continues to move at a low and constant speed; otherwise, the screw is considered to have reached the required torque and the screw stops moving.

[0003] However, in actual mechanical structures, due to the presence of external forces such as structural friction and elasticity, as well as the effects of structural fatigue, the relationship between current and output torque exhibits a non-linearity. Furthermore, the conversion coefficient varies depending on the position of the mechanism, resulting in low accuracy and significant error when controlling torque solely through current control during actual fastening. During speed switching, it is difficult to control the transition point from high to low speed. Switching too late can easily lead to torque overshoot, damaging the product; switching too early results in a longer low-speed running time, affecting efficiency. Controlling whether to continue low-speed uniform motion by obtaining feedback values ​​from the torque sensor is difficult to control at low speeds, and this control method cannot simultaneously satisfy cycle efficiency and control accuracy. If the low-speed value is too large, it can easily cause torque overshoot; if the low-speed value is too small, it affects efficiency.

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

[0005] The main objective of this application is to provide an electric screwdriver control method, device, equipment, and storage medium based on torque closed-loop control, aiming to solve the technical problems of excessively long cycle time, low torque control accuracy, and excessive overshoot when increasing the gain of the torque closed-loop controller during electric screwdriver locking.

[0006] To achieve the above objectives, this application proposes an electric screwdriver control method based on torque closed-loop control, the method comprising:

[0007] Control the electric screwdriver to move from the initial first preset position to the second preset position;

[0008] After the electric screwdriver reaches the second preset position, the electric screwdriver is controlled to run at a constant speed at a first preset speed;

[0009] When the electric screwdriver is running at a constant speed at a first preset speed, the torque feedback value of the torque sensor is collected in real time. When the torque feedback value is greater than the first preset torque, the torque feedback value and the second preset torque are input into the torque control loop.

[0010] The electric screwdriver is controlled to operate based on the drive current output by the torque control loop;

[0011] When the torque feedback value equals the second preset torque, the electric screwdriver is controlled to stop tightening.

[0012] In one embodiment, before the step of controlling the electric screwdriver to move from an initial first preset position to a second preset position, the following steps are included:

[0013] Self-learning phase for obtaining idle travel distance: During trial operation before the start of the process, the electric screwdriver is controlled to start running from the first preset position at the second preset speed, and the torque feedback value is detected during the movement.

[0014] When the torque feedback value is greater than or equal to the third preset torque, the position of the electric screwdriver at this moment is recorded as the second preset position.

[0015] In one embodiment, the step of controlling the electric screwdriver to move from an initial first preset position to a second preset position includes:

[0016] The electric screwdriver is controlled to accelerate from a standstill to a third preset speed starting from a first preset position, and then runs at the third preset speed; the third preset speed is greater than the first preset speed.

[0017] When the electric screwdriver reaches the third preset position, the electric screwdriver is controlled to change from the third preset speed to the first preset speed;

[0018] The electric screwdriver is controlled to run at a first preset speed at a constant speed until it reaches the second preset position.

[0019] In one embodiment, before the step of acquiring the torque feedback value of the torque sensor in real time when the electric screwdriver is running at a first preset speed at a constant speed, and inputting the torque feedback value and a second preset torque into the torque control loop when the torque feedback value is greater than the first preset torque, the method includes:

[0020] The second preset torque is obtained by filtering the target torque using a tracking differentiator; wherein the transfer function of the tracking differentiator is:

[0021]

[0022] in,

[0023]

[0024] U(s) is the input of the tracking differentiator, i.e., the target torque; Y(s) is the output, i.e., the second preset torque; r is the convergence speed; and Ts is the control period.

[0025] In one embodiment, after the step of controlling the operation of the electric screwdriver based on the drive current output by the torque control loop, the method further includes:

[0026] When the electric screwdriver is controlled by the driving current, the feedback current of the electric screwdriver is collected in real time.

[0027] When the feedback current is different from the drive current, the feedback current is adjusted so that the output torque of the electric screwdriver is equal to the target torque.

[0028] In one embodiment, after the step of controlling the electric screwdriver to move from an initial first preset position to a second preset position, the following steps are included:

[0029] During operation of the electric screwdriver, the torque feedback value and the current position of the electric screwdriver are detected.

[0030] An alarm will be triggered and the system will shut down when the torque feedback value is detected to be greater than the torque protection threshold or the current position is greater than the position protection threshold.

[0031] In one embodiment, after the step of controlling the electric screwdriver to stop tightening when the torque feedback value is equal to the second preset torque, the method includes:

[0032] When loosening, the electric screwdriver is controlled to reverse and move to the first preset position;

[0033] When the electric screwdriver reaches the first preset position, the electric screwdriver is controlled to stop running.

[0034] Furthermore, to achieve the above objectives, this application also proposes an electric screwdriver control device based on torque closed-loop control, the device comprising:

[0035] The position control module is used to control the electric screwdriver to move from an initial first preset position to a second preset position;

[0036] The speed control module is used to control the electric screwdriver to run at a constant speed at a first preset speed after the electric screwdriver reaches the second preset position.

[0037] The torque judgment module is used to collect the torque feedback value of the torque sensor in real time when the electric screwdriver is running at a constant speed at a first preset speed. When the torque feedback value is greater than the first preset torque, the torque feedback value and the second preset torque are input into the torque control loop.

[0038] The torque control module is used to control the operation of the electric screwdriver according to the target torque output by the torque control loop;

[0039] The torque stop module is used to control the electric screwdriver to stop tightening when the torque feedback value is equal to the second preset torque.

[0040] Furthermore, to achieve the above objectives, this application also proposes an electric screwdriver control device based on torque closed-loop control, the device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the electric screwdriver control method based on torque closed-loop control as described above.

[0041] In addition, to achieve the above objectives, this application also proposes a storage medium, which is a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the steps of the torque-based closed-loop electric screwdriver control method described above.

[0042] This application discloses a torque-based closed-loop control method, apparatus, device, and storage medium for electric screwdrivers, relating to the field of automatic control technology. The torque-based closed-loop control method for electric screwdrivers involves: controlling the electric screwdriver to move from an initial first preset position to a second preset position; after the electric screwdriver reaches the second preset position, controlling it to run at a first preset speed; while the electric screwdriver is running at the first preset speed, acquiring the torque feedback value from a torque sensor in real time; when the torque feedback value is greater than the first preset torque, inputting the torque feedback value and a second preset torque into a torque control loop; controlling the electric screwdriver to run according to the target torque output by the torque control loop; and controlling the electric screwdriver to stop tightening when the torque feedback value equals the second preset torque. A segmented speed regulation based on a position control mode is adopted, adjusting the proportion of the low-speed segment in the total stroke distance to meet cycle efficiency while ensuring that position overshoot does not cause torque overshoot and damage to the product. By acquiring torque feedback values ​​in real time through a torque sensor, and inputting these values ​​into a second preset torque control loop, the electric screwdriver is controlled to operate based on the target torque output by the torque control loop. This satisfies the requirement for rapid torque following while suppressing overshoot generated by the torque controller. Attached Figure Description

[0043] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0044] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a flowchart illustrating an embodiment of the torque-closed-loop-based electric screwdriver control method of this application.

[0046] Figure 2 This is a speed-torque waveform diagram provided for Embodiment 1 of the electric screwdriver control method based on torque closed loop in this application;

[0047] Figure 3 This is a flowchart illustrating Embodiment 2 of the electric screwdriver control method based on torque closed-loop in this application.

[0048] Figure 4 This is a flowchart illustrating Embodiment 3 of the electric screwdriver control method based on torque closed-loop in this application.

[0049] Figure 5 This is a schematic diagram of the structure provided in Embodiment 3 of the electric screwdriver control method based on torque closed loop of this application;

[0050] Figure 6 This is a schematic diagram of the module structure of the electric screwdriver control device based on torque closed-loop according to an embodiment of this application;

[0051] Figure 7 This is a schematic diagram of the structure of the torque-closed-loop electric screwdriver control device in the hardware operating environment of the torque-closed-loop electric screwdriver control method in the embodiments of this application.

[0052] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0053] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application.

[0054] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0055] The main solution of this application embodiment is as follows: control the electric screwdriver to move from an initial first preset position to a second preset position; after the electric screwdriver reaches the second preset position, control the electric screwdriver to run at a first preset speed; while the electric screwdriver is running at the first preset speed, collect the torque feedback value of the torque sensor in real time; when the torque feedback value is greater than the first preset torque, input the torque feedback value and the second preset torque into the torque control loop; control the electric screwdriver to run according to the target torque output by the torque control loop; when the torque feedback value is equal to the second preset torque, control the electric screwdriver to stop tightening.

[0056] Before tightening the electric screwdriver, the current needs to be calibrated using a torque tester to obtain the conversion coefficient between current and output torque. The target torque is then multiplied by the conversion coefficient to obtain the required control current. The tightening process uses segmented speed regulation based on a speed mode. A higher speed is used when the screw is being threaded, and the speed is reduced to a lower speed as the screw tightens. If the torque sensor feedback value is less than the target torque, the screw continues to move at a low and constant speed; otherwise, the screw is considered to have reached the required torque and the screw stops moving.

[0057] However, in actual mechanical structures, due to the presence of external forces such as structural friction and elasticity, as well as the effects of structural fatigue, the relationship between current and output torque exhibits a non-linearity. Furthermore, the conversion coefficient varies depending on the position of the mechanism, resulting in low accuracy and significant error when controlling torque solely through current control during actual fastening. During speed switching, it is difficult to control the transition point from high to low speed. Switching too late can easily lead to torque overshoot, damaging the product; switching too early results in a longer low-speed running time, affecting efficiency. Controlling whether to continue low-speed uniform motion by obtaining feedback values ​​from the torque sensor is difficult to control at low speeds, and this control method cannot simultaneously satisfy cycle efficiency and control accuracy. If the low-speed value is too large, it can easily cause torque overshoot; if the low-speed value is too small, it affects efficiency.

[0058] This application provides a solution that uses self-learning to obtain the travel distance, improving efficiency while ensuring that position overshoot does not damage the product. The tightening stage consists of two speeds: high speed and low speed, resulting in a smoother transition from position mode to the torque probing stage. In the torque closed-loop stage, a differential tracker filters the target torque to obtain a second preset torque. This second preset torque, along with the torque feedback value, is input into the torque control loop, enabling the closed-loop controller to respond quickly and without overshoot. Simultaneously, torque and travel are monitored in real-time throughout the process to prevent product damage.

[0059] It should be noted that the executing entity in this embodiment can be a computing service device with data processing, network communication, and program execution functions, such as a tablet computer, personal computer, or mobile phone, or a torque-based closed-loop electric screwdriver control device capable of achieving the above functions. The following description uses an electric screwdriver control device as an example to illustrate this embodiment and the subsequent embodiments.

[0060] Based on this, embodiments of this application provide an electric screwdriver control method based on torque closed-loop control, referring to... Figure 1 , Figure 1 This is a flowchart illustrating the first embodiment of the electric screwdriver control method based on torque closed-loop according to this application.

[0061] In this embodiment, the electric screwdriver control method based on torque closed-loop includes steps S10 to S50:

[0062] Step S10: Control the electric screwdriver from the initial first preset position P start Run to the second preset position P end .

[0063] It should be noted that an electric screwdriver typically refers to an electric screwdriver, a power tool used for quickly tightening or loosening screws, commonly found in industrial production and repair fields. In assembly lines or mass production, it quickly completes screw fastening (such as in the assembly of electronic products, furniture, and home appliances), replacing manual screwdrivers, reducing wrist strain from repetitive movements. Some electric screwdrivers can be set with torque settings to prevent screws from being overtightened and damaged. This application proposes a method for automatically controlling the tightening or loosening of screws with an electric screwdriver.

[0064] It is understandable that, such as Figure 2 As shown, during the two-stage tightening phase, a higher speed is used when the screw is being threaded, and the speed is reduced to a lower speed when tightening. The starting position of the electric screwdriver is set to the first preset position P. start The endpoint is the second preset position P. end The travel distance (P) end -P start The journey is divided into high-speed and low-speed segments, with the high-speed segment accounting for (1-K). x The high-speed speed is the third preset speed V. hig K x This is the stroke ratio coefficient for the low-speed segment, where the low-speed speed is the first preset speed V. arv When the electric screwdriver reaches the endpoint position, the second preset position P end Then, we move on to the next stage.

[0065] Specifically, the low-speed stage of the two-stage tightening phase is the first preset speed V. arv With speed V arv The distance traveled at a constant speed is (P) end -P start )*K x .

[0066] S20: When the electric screwdriver reaches the second preset position P end Then, the electric screwdriver is controlled to operate at a first preset speed V.arv Running at a constant speed.

[0067] Understandably, the next stage after the two-speed tightening stage is the torque testing stage, in which the speed is the first preset speed V. arv The speed control mode controls the electric screwdriver to operate at a first preset speed V. arv Running at a constant speed.

[0068] Step S31 is included before step S30.

[0069] Step S31: Track the target torque F using the tracking differentiator tar The second preset torque is obtained by filtering; wherein, the transfer function of the tracking differentiator is:

[0070]

[0071] in,

[0072]

[0073] U(s) is the input of the tracking differentiator, i.e., the target torque F. tar Y(s) is the output, i.e., the second preset torque, r is the convergence speed, and Ts is the control period.

[0074] It should be noted that because the torque control loop requires a large input when the error is significant, and using a high control gain will result in a large overshoot, it is difficult to balance overshoot and speed. Adding a tracking differentiator to control the target torque F... tar The second preset torque is obtained by filtering. The difference between the second preset torque and the torque feedback value is used as the input to the torque control loop, which can satisfy the requirements of torque tracking speed while suppressing overshoot generated by the torque controller. Target torque F tar To ensure that screws do not loosen due to insufficient torque, or that screws, connected parts, or threads are damaged due to excessive torque, the torque of the electric screwdriver is used.

[0075] It is understandable that the transfer function of the tracking differentiator is:

[0076]

[0077] Forward Euler discretization is employed, i.e.

[0078]

[0079] have to:

[0080] Y(k)=r 2 T s 2 u(k)+(2-2rT s)Y(k-1)-(rT s -1) 2 Y(k-2)

[0081] Where U(s) is the input of the tracking differentiator, i.e., the target torque F. tar Y(s) is the output, i.e. the second preset torque, r is the convergence speed, and Ts is the control period.

[0082] Step S30: The electric screwdriver is driven at a first preset speed V arv During constant speed operation, the torque feedback value of the torque sensor is collected in real time. When the torque feedback value is greater than the first preset torque F, tar *K f At that time, the torque feedback value is compared with the second preset torque input torque control loop.

[0083] It should be noted that the electric screwdriver is equipped with a torque sensor to collect torque feedback values ​​in real time. The relationship between the drive current and output torque of the electric screwdriver is non-linear, and the conversion coefficient varies depending on its structural position. f To switch the torque ratio, when the torque sensor collects a torque feedback value greater than F... tar *K f At that time, it enters the next stage of torque closed-loop stage, F tar *K f This is the first preset torque.

[0084] It is understandable that, during the torque closed-loop stage, the target torque F tar After passing through the tracking differentiator, the filtered torque is the second preset torque. The difference between the second preset torque and the torque feedback value is the input of the torque control loop. When the torque feedback value reaches the second preset torque, the next stage, the loosening stage, begins.

[0085] Step S40: Control the operation of the electric screwdriver according to the drive current output by the torque control ring.

[0086] It should be noted that during the torque closed-loop stage, the torque control loop outputs drive current to control the operation of the electric screwdriver. The electric screwdriver in this application is a servo motor-driven electric screwdriver, also known as a smart electric screwdriver or smart screwdriver. It is a high-precision, high-performance power tool mainly used for tightening and loosening screws. The working principle of the servo motor is that it receives drive current and adjusts its output torque and speed according to changes in the drive current. The servo motor adjusts its torque and speed based on the received drive current and outputs corresponding mechanical energy.

[0087] Specifically, electric screwdrivers can achieve high-speed real-time detection and high-precision control of tightening torque values, and the torque can be controlled in both forward and reverse directions. Their locking accuracy is extremely high, ensuring that every screw is tightened to the set torque requirement. At the same time, electric screwdrivers have a very fast response speed; the acceleration time from 0 r / min to 3000 r / min is typically within 7ms, which is unmatched by ordinary electric screwdrivers. Electric screwdrivers also support absolute position control and soft limits, reducing potential failure points and improving work stability.

[0088] Step S50: When the torque feedback value is equal to the second preset torque, control the electric screwdriver to stop tightening.

[0089] It should be noted that when the torque feedback value reaches the second preset torque, it means that the torque feedback value has reached the target torque F. tar The screws are now tightened, and the electric screwdriver locking process is complete.

[0090] In this embodiment, a torque-based closed-loop control method for electric screwdrivers is proposed, which can significantly improve the control accuracy of electric screwdriver torque and greatly shorten the tightening and loosening cycle time. During the two-speed tightening stage, a position-mode-based two-speed planning method is used to determine the high-speed and low-speed travel of the electric screwdriver. The electric screwdriver reaches the second preset position P. end Then, the process switches to the torque testing phase, controlling the electric screwdriver to operate at a first preset speed V. arv Running at a constant speed, when the detected torque feedback value is greater than the first preset torque F tar *K f At this point, the system switches to the torque closed-loop stage, where the target torque F is controlled by a tracking differentiator. tar The second preset torque is obtained by filtering. The difference between the second preset torque and the torque feedback is used as the input of the torque control loop. When the torque feedback value reaches the second preset torque, it is determined that the screw has been tightened.

[0091] Based on the first embodiment of this application, in the second embodiment of this application, the content that is the same as or similar to that in the first embodiment described above can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 2 , Figure 2 This is a flowchart illustrating Embodiment 2 of the electric screwdriver control method based on torque closed-loop in this application.

[0092] Prior to step S10, the torque-based closed-loop electric screwdriver control method includes steps S201 and S202.

[0093] Understandably, Position Control Mode involves setting a target position, and the control system automatically calculates and adjusts parameters such as speed and acceleration to ensure the electric screwdriver accurately reaches and stops at the target position. The system compares the deviation between the actual position and the target position in real time and dynamically adjusts the output to achieve high-precision positioning. Velocity Control Mode, on the other hand, involves setting a target speed, and the control system adjusts the output of the electric screwdriver to maintain a constant speed. The system compares the deviation between the actual speed and the target speed in real time and dynamically adjusts the output to achieve speed stability.

[0094] Step S201: Self-learning stage for obtaining idle travel distance: During trial operation before the start of the process, the electric screwdriver is controlled to move from the first preset position P. start At the second preset speed V learn Start running and detect torque feedback values ​​during movement.

[0095] Understandably, a self-learning phase precedes the second-speed tightening stage. A trial run is conducted before the process begins, using a lower, second preset speed V. learn From the starting point, the first preset position P start It moves at a constant speed when it is open.

[0096] Step S202: When the torque feedback value is greater than or equal to the third preset torque F learn At that moment, the position of the electric screwdriver is recorded as the second preset position P. end .

[0097] It should be noted that when the torque sensor detects a torque feedback value greater than or equal to the third preset torque F... learn When the motion stops, record the current position as the endpoint position, the second preset position P. end Then, return to the initial position, the first preset position P. start The self-learning phase is conducted only once, either before the start of the process or after a product change, with the aim of obtaining the second preset position P at the endpoint. end Among them, the third preset torque F learn This is the self-learning torque threshold.

[0098] In step S10, the electric screwdriver control method based on torque closed loop includes steps S203 to S205.

[0099] Step S203: Control the electric screwdriver to move from the first preset position P start Start by accelerating from a standstill to the third preset speed V. hig and at the third preset speed V hig Running; the third preset speed V hig Greater than the first preset speed V arv.

[0100] It is understandable that, such as Figure 2 As shown, the two-speed tightening stage is divided into a high-speed stage and a low-speed stage. In the high-speed stage, the electric screwdriver is controlled to accelerate from a standstill to the third preset speed V. hig On the high-speed section, the electric screwdriver's stroke is (P end -P start )*(1-K x ).

[0101] Step S204: When the electric screwdriver reaches the third preset position, control the electric screwdriver to move from the third preset speed V. hig Change to the first preset speed V arv .

[0102] It is understandable that during the second-speed tightening stage, when the electric screwdriver's stroke is close to (P) end -P start )*(1-K x When the electric screwdriver starts to decelerate from the third preset speed V, the control system decelerates the screwdriver. hig Change to the first preset speed V arv Entering the low-speed range, the stroke of the electric screwdriver in the low-speed range is (P) end -P start )*K x The total stroke of the two-stage fast tightening phase is (P) end -P start ), K x The low-speed travel ratio coefficient, (1-K) x ) represents the percentage of high-speed travel, and the third preset position represents the high-speed travel (P). end -P start )*(1-K x Add the first preset position P start The third preset position = P start +(P end -P start )*(1-K x ).

[0103] Step S205: Control the electric screwdriver to operate at a first preset speed V arv Run at a constant speed until the electric screwdriver reaches the second preset position P. end .

[0104] It is understandable that, in the low-speed range, when the electric screwdriver reaches the second preset position P, the end point... end Then, we move on to the next stage.

[0105] In this embodiment, a trial run is conducted before the process begins, at a lower speed, a second preset speed V. learn From the starting point, the first preset position Pstart The engine moves at a constant speed when in motion. When the torque sensor detects a torque feedback value greater than or equal to the third preset torque F... learn When the motion stops, record the current position as the endpoint position, the second preset position P. end Then, return to the initial position, the first preset position P. start During the second-speed tightening stage, the electric screwdriver accelerates from a standstill to the third preset speed V. hig The electric screwdriver's stroke is (P) end -P start )*(1-K x ), when the electric screwdriver's stroke is close to (P) end -P start )*(1-K x When the electric screwdriver reaches (P), it is controlled to decelerate from the third preset speed Vhig, and when the electric screwdriver reaches (P) end -P start )*(1-K x At position, the velocity becomes the first preset velocity V. arv Control the electric screwdriver to operate at a first preset speed V arv Run to the second preset position P end The system acquires the idle travel distance through self-learning, and divides the obtained travel distance into high-speed and low-speed segments. It adopts a two-speed system based on position control mode. By adjusting the proportion of the low-speed segment distance in the total travel distance, it satisfies the cycle efficiency while ensuring that the position does not overshoot, which could lead to torque overshoot and damage to the product.

[0106] Based on the first and / or second embodiments of this application, in the third embodiment of this application, the content that is the same as or similar to that in embodiments one and two above can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 4 , Figure 4 This is a flowchart illustrating Embodiment 3 of the electric screwdriver control method based on torque closed-loop in this application.

[0107] Following step S10, the torque-based closed-loop electric screwdriver control method further includes steps S301 and S302.

[0108] Step S301: When the electric screwdriver is running, detect the torque feedback value of the electric screwdriver and the current position of the electric screwdriver.

[0109] It should be noted that a position sensor is a device capable of detecting changes in the position of an object, and it can convert the object's position information into an electrical signal output. The electric screwdriver of this application includes a position sensor to detect the current position of the electric screwdriver.

[0110] Step S302: When the torque feedback value is detected to be greater than the torque protection threshold F maxOr the current position is greater than the position protection threshold P. max When the alarm sounds, the machine shuts down.

[0111] Understandably, the real-time torque feedback value of the torque sensor and the current position of the electric screwdriver are monitored throughout the process. When the torque feedback value exceeds the torque protection threshold F... max Or the current location is greater than the location protection threshold P. max If an alarm sounds and the machine stops, troubleshooting will be performed.

[0112] In step S40, the electric screwdriver control method based on torque closed loop further includes steps S303 and S304.

[0113] Step S303: When the electric screwdriver is running under the control of the driving current, the feedback current of the electric screwdriver is collected in real time.

[0114] It is understandable that by adding a tracking differentiator to the target torque F tar The second preset torque is obtained by filtering. The difference between the second preset torque and the torque feedback value is used as the input of the torque control loop. The torque control loop outputs the drive current. However, as the detected torque feedback value approaches the second preset torque, the torque required to tighten the screw also increases, and the drive current required by the servo motor also increases. However, because the screw has friction that hinders the movement of the servo motor and the servo motor itself has a delay, the drive current is different from the feedback current collected from the electric screwdriver servo motor.

[0115] Step S304: When the feedback current and the drive current are not the same, adjust the feedback current so that the output torque of the electric screwdriver is equal to the target torque F. tar .

[0116] It should be noted that, as Figure 5 As shown, the torque control loop outputs a drive current to the current control loop. The difference between the drive current and the feedback current is the input to the current control loop. The output of the current control loop adjusts the feedback current of the servo motor so that the output torque of the electric screwdriver is equal to the target torque F. tar .

[0117] Following step S50, the torque-based closed-loop electric screwdriver control method further includes steps S305 and S306.

[0118] Step S305: When loosening, control the electric screwdriver to reverse and move to the first preset position P. start .

[0119] It is understandable that, such as Figure 2 As shown, during the loosening phase, a position control mode with a final velocity of 0 is adopted. The system returns from the current position to the starting position, the first preset position P. startThis completes a tightening and loosening process.

[0120] Step S306: When the electric screwdriver reaches the first preset position P start When this happens, the electric screwdriver is stopped from operating.

[0121] It should be noted that the electric screwdriver accelerates in reverse from a standstill until it reaches a preset speed, such as the third preset speed V. hig After running for a period of time, it approaches the first preset position P near the starting point. start When the electric screwdriver reaches the first preset position, it begins to decelerate until it stops operating.

[0122] In this embodiment, during the torque testing phase, the electric screwdriver operates at a first preset speed V. arv When operating at a low and constant speed, the torque feedback value is greater than the first preset torque F. tar *K f At this point, the torque closed-loop stage begins. The difference between the torque feedback value and the second preset torque is input to the torque control loop. The torque control outputs a drive current to the current control loop. The feedback current of the electric screwdriver servo motor is collected, and the difference between the drive current and the feedback current is used as the input to the current control loop. The current control loop adjusts the feedback current inside the servo motor so that the output torque of the electric screwdriver is equal to the target torque F. tar During the loosening phase, a position control mode with a final velocity of 0 is used to control the electric screwdriver to return from its current position to the starting position, the first preset position P. start Furthermore, during the operation of the electric screwdriver, the torque feedback value and current position of the electric screwdriver are monitored in real time to prevent product damage.

[0123] It should be noted that the above examples are only for understanding this application and do not constitute a limitation on the torque-based closed-loop electric screwdriver control method of this application. Any simple modifications based on this technical concept are within the protection scope of this application.

[0124] This application also provides an electric screwdriver control device based on torque closed-loop control, please refer to... Figure 6 The torque-closed-loop-based electric screwdriver control device includes:

[0125] The position control module 10 is used to control the electric screwdriver to move from the initial first preset position to the second preset position.

[0126] The speed control module 20 is used to control the electric screwdriver to run at a constant speed at a first preset speed after the electric screwdriver reaches the second preset position.

[0127] The torque judgment module 30 is used to collect the torque feedback value of the torque sensor in real time when the electric screwdriver is running at a first preset speed. When the torque feedback value is greater than the first preset torque, the torque feedback value and the second preset torque are input into the torque control loop.

[0128] The torque control module 40 is used to control the operation of the electric screwdriver according to the target torque output by the torque control loop.

[0129] The torque stop module 50 is used to control the electric screwdriver to stop tightening when the torque feedback value is equal to the second preset torque.

[0130] The torque-closed-loop-based electric screwdriver control device provided in this application, employing the torque-closed-loop-based electric screwdriver control method described in the above embodiments, can solve the technical problems of excessively long cycle time during electric screwdriver locking, excessively low torque control accuracy, and excessive overshoot when increasing the gain of the torque closed-loop controller. Compared with the prior art, the beneficial effects of the torque-closed-loop-based electric screwdriver control device provided in this application are the same as those of the torque-closed-loop-based electric screwdriver control method provided in the above embodiments, and other technical features in the torque-closed-loop-based electric screwdriver control device are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.

[0131] This application provides an electric screwdriver control device based on torque closed-loop control. The electric screwdriver control device based on torque closed-loop control includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to execute the electric screwdriver control method based on torque closed-loop control in the first embodiment described above.

[0132] The following is for reference. Figure 7 This document illustrates a structural schematic diagram of an electric screwdriver control device suitable for implementing embodiments of this application based on a torque closed-loop control. The torque closed-loop control device in the embodiments of this application may include, but is not limited to, mobile terminals such as mobile phones, laptops, digital radio receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Description), PMPs (Portable Media Players), and in-vehicle terminals (e.g., in-vehicle navigation terminals), as well as fixed terminals such as digital TVs and desktop computers. Figure 7 The torque-based closed-loop electric screwdriver control device shown is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of this application.

[0133] like Figure 7As shown, the torque-closed-loop-based electric screwdriver control device may include a processing unit 1001 (e.g., a central processing unit, a graphics processor, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1002 or a program loaded from a storage device 1003 into a random access memory (RAM) 1004. The RAM 1004 also stores various programs and data required for the operation of the torque-closed-loop-based electric screwdriver control device. The processing unit 1001, ROM 1002, and RAM 1004 are interconnected via a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Typically, the following systems can be connected to I / O interface 1006: input devices 1007 including, for example, touchscreens, touchpads, keyboards, mice, image sensors, microphones, accelerometers, gyroscopes, etc.; output devices 1008 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; storage devices 1003 including, for example, magnetic tapes, hard disks, etc.; and communication devices 1009. Communication device 1009 allows the torque-closed-loop based electric screwdriver control device to communicate wirelessly or wiredly with other devices to exchange data. Although torque-closed-loop based electric screwdriver control devices with various systems are shown in the figures, it should be understood that it is not required to implement or possess all the systems shown. More or fewer systems may be implemented alternatively.

[0134] Specifically, according to the embodiments disclosed in this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments disclosed in this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication device, or installed from storage device 1003, or installed from ROM 1002. When the computer program is executed by processing device 1001, it performs the functions defined in the methods of the embodiments disclosed in this application.

[0135] The torque-closed-loop-based electric screwdriver control device provided in this application, employing the torque-closed-loop-based electric screwdriver control method described in the above embodiments, can solve the technical problems of excessively long cycle time during electric screwdriver locking, excessively low torque control accuracy, and excessive overshoot when increasing the gain of the torque closed-loop controller. Compared with the prior art, the beneficial effects of the torque-closed-loop-based electric screwdriver control device provided in this application are the same as those of the torque-closed-loop-based electric screwdriver control method provided in the above embodiments, and other technical features in this torque-closed-loop-based electric screwdriver control device are the same as those disclosed in the previous embodiment method, and will not be repeated here.

[0136] It should be understood that the various parts disclosed in this application can be implemented using hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0137] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0138] This application provides a computer-readable storage medium having computer-readable program instructions (i.e., a computer program) stored thereon, the computer-readable program instructions being used to execute the torque-based closed-loop electric screwdriver control method in the above embodiments.

[0139] The computer-readable storage medium provided in this application may be, for example, a USB flash drive, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, system, or device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0140] The aforementioned computer-readable storage medium may be included in a torque-closed-loop-based electric screwdriver control device; or it may exist independently and not assembled into a torque-closed-loop-based electric screwdriver control device.

[0141] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a Local Area Network (LAN) or a Wide Area Network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0142] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0143] The modules described in the embodiments of this application can be implemented in software or hardware. The names of the modules do not necessarily limit the functionality of the unit itself.

[0144] The readable storage medium provided in this application is a computer-readable storage medium that stores computer-readable program instructions (i.e., a computer program) for executing the above-described torque-based closed-loop electric screwdriver control method. This solves the technical problems of excessively long cycle time during electric screwdriver locking, low torque control accuracy, and excessive overshoot when increasing the gain of the torque closed-loop controller. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in this application are the same as those of the torque-based closed-loop electric screwdriver control method provided in the above embodiments, and will not be repeated here.

[0145] The above description is only a part of the embodiments of this application and does not limit the scope of this application. All equivalent structural transformations made under the technical concept of this application and using the content of this application specification and drawings, or direct / indirect applications in other related technical fields, are included within the protection scope of this application.

Claims

1. A torque-based closed-loop control method for electric screwdrivers, characterized in that, The method includes: Control the electric screwdriver to move from the initial first preset position to the second preset position; The travel distance is divided into high-speed segment and low-speed segment, with the high-speed speed being the third preset speed and the low-speed speed being the first preset speed; After the electric screwdriver reaches the second preset position, the electric screwdriver is controlled to run at a constant speed at a first preset speed; The second preset torque is obtained by filtering the target torque using a tracking differentiator; When the electric screwdriver is running at a constant speed at a first preset speed, the torque feedback value of the torque sensor is collected in real time. When the torque feedback value is greater than the first preset torque, the torque feedback value and the second preset torque are input into the torque control loop. The electric screwdriver is controlled to operate based on the drive current output by the torque control loop; When the torque feedback value is equal to the second preset torque, the electric screwdriver is controlled to stop tightening. Wherein, the first preset torque is F tar K f F tar K is the target torque. f To switch the torque ratio.

2. The electric screwdriver control method based on torque closed-loop as described in claim 1, characterized in that, Before the step of controlling the electric screwdriver to move from the initial first preset position to the second preset position, the following steps are included: Self-learning phase for obtaining idle travel distance: During trial operation before the start of the process, the electric screwdriver is controlled to start running from the first preset position at the second preset speed, and the torque feedback value is detected during the movement. When the torque feedback value is greater than or equal to the third preset torque, the position of the electric screwdriver at this moment is recorded as the second preset position.

3. The electric screwdriver control method based on torque closed-loop as described in claim 1, characterized in that, The step of controlling the electric screwdriver to move from an initial first preset position to a second preset position includes: The electric screwdriver is controlled to accelerate from a standstill to a third preset speed starting from the first preset position, and then runs at the third preset speed. The third preset speed is greater than the first preset speed; When the electric screwdriver reaches the third preset position, the electric screwdriver is controlled to change from the third preset speed to the first preset speed; The electric screwdriver is controlled to run at a first preset speed at a constant speed until it reaches the second preset position.

4. The electric screwdriver control method based on torque closed-loop as described in claim 1, characterized in that, Before the step of real-time acquisition of torque feedback values ​​from a torque sensor when the electric screwdriver is running at a first preset speed at a constant speed, and inputting the torque feedback value and a second preset torque into the torque control loop when the torque feedback value is greater than the first preset torque,... include: The transfer function of the tracking differentiator is: in, U(s) is the input of the tracking differentiator, i.e., the target torque; Y(s) is the output, i.e., the second preset torque; r is the convergence speed; and Ts is the control period.

5. The electric screwdriver control method based on torque closed-loop as described in claim 4, characterized in that, After the step of controlling the operation of the electric screwdriver based on the drive current output by the torque control loop, the method further includes: When the electric screwdriver is controlled by the driving current, the feedback current of the electric screwdriver is collected in real time. When the feedback current is different from the drive current, the feedback current is adjusted so that the output torque of the electric screwdriver is equal to the target torque.

6. The electric screwdriver control method based on torque closed-loop as described in claim 1, characterized in that, After the step of controlling the electric screwdriver to move from the initial first preset position to the second preset position, the following steps are included: During operation of the electric screwdriver, the torque feedback value of the electric screwdriver and the current position of the electric screwdriver are detected; An alarm will be triggered and the system will shut down when the torque feedback value is detected to be greater than the torque protection threshold or the current position is greater than the position protection threshold.

7. The electric screwdriver control method based on torque closed-loop as described in claim 1, characterized in that, After the step of controlling the electric screwdriver to stop tightening when the torque feedback value is equal to the second preset torque, the following steps are included: When loosening, the electric screwdriver is controlled to reverse and move to the first preset position; When the electric screwdriver reaches the first preset position, the electric screwdriver is controlled to stop running.

8. An electric screwdriver control device based on torque closed-loop control, characterized in that, The device includes: The position control module is used to control the electric screwdriver to move from an initial first preset position to a second preset position; The speed control module is used to control the electric screwdriver to run at a constant speed at a first preset speed after the electric screwdriver reaches the second preset position. The torque judgment module is used to collect the torque feedback value of the torque sensor in real time when the electric screwdriver is running at a constant speed at a first preset speed. When the torque feedback value is greater than the first preset torque, the torque feedback value and the second preset torque are input into the torque control loop. The torque control module is used to control the operation of the electric screwdriver according to the target torque output by the torque control loop; The torque stop module is used to control the electric screwdriver to stop tightening when the torque feedback value is equal to the second preset torque. The torque acquisition module is used to filter the target torque through a tracking differentiator to obtain a second preset torque; The speed control module is also used to divide the travel distance into a high-speed segment and a low-speed segment, with the high-speed speed being the third preset speed and the low-speed speed being the first preset speed. The torque determination module is also used to determine the first preset torque as F. tar K f F tar K is the target torque. f To switch the torque ratio.

9. An electric screwdriver control device based on torque closed-loop control, characterized in that, The device includes: a memory, a processor, and a computer program stored in the memory and running on the processor, the computer program being configured to implement the steps of the torque-based closed-loop electric screwdriver control method as described in any one of claims 1 to 7.

10. A storage medium, characterized in that, The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, it implements the steps of the torque-based closed-loop electric screwdriver control method as described in any one of claims 1 to 7.

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