Fastening control method of power tool

Abstract

The application discloses a fastening control method of an electric tool, and the method comprises the following steps: increasing a speed limit setting value and a torque setting value on a chuck; and adjusting the output of the speed limit setting value and the torque setting value on the chuck according to a torque detection value, a speed detection value and a position detection value. The fastening control method of the electric tool provided by the application adjusts the output of the speed limit setting value and the torque setting value on the chuck through the torque detection value, the speed detection value and the position detection value; the fastening logic of the electric tool is simplified, the complexity and the cost of the control system are reduced; the configuration parameters are reduced, the working condition adaptability is improved, and the production efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric machines, in particular to a fastening control method of an electric tool. BACKGROUND

[0002] The electric tool is usually used for fastening and loosening screws or nuts, and is one of the tools indispensable for most production enterprises. In the fastening process of the screws or nuts, the control accuracy of the torque directly affects the production quality. Too large torque will cause thread stripping, and too small torque will cause loosening. The fastening speed of the screws or nuts directly affects the production efficiency.

[0003] In order to reduce the fastening time and improve the torque accuracy, the current common fastening scheme controls the fastening torque and the fastening speed according to different working conditions in stages. For example, in the fitting stage, the preset fitting speed is used for fast fitting. If it is detected in the fitting process that the torque exceeds the preset fitting torque, it is considered that the fitting is completed, the speed is reduced to the preset fastening speed, and then the fastening stage is switched to. In the fastening stage, the preset torque and the preset speed are used for slow fastening. Since the fastening is divided into multiple stages, a large number of process parameters need to be configured. In addition, the working conditions are complex in engineering application, for example, the initial states of the screws or nuts are different, the fitting strokes are different, the dynamic switching between different stages needs to be considered, and the control logic is very complex, and further increases the configuration parameters. Therefore, the electric tool needs to frequently switch the process parameters according to the working conditions in the actual use process, which increases the operation complexity and reduces the production efficiency. SUMMARY

[0004] The present application aims to provide a fastening control method of an electric tool to solve the problems of complex configuration parameters and poor working condition adaptability in the fastening process of the existing electric tool.

[0005] The present application provides a fastening control method of an electric tool, the electric tool comprising an electric machine and a chuck; the method comprising:

[0006] increasing the speed limit setting value and the torque setting value on the chuck;

[0007] adjusting the output of the speed limit setting value and the torque setting value on the chuck according to the torque detection value, the speed detection value and the position detection value.

[0008] The fastening control method of the electric tool provided by the present application adjusts the output of the speed limit setting value and the torque setting value on the chuck through the torque detection value, the speed detection value and the position detection value. The fastening logic of the electric tool is simplified, the complexity and cost of the control system are reduced, the configuration parameters are reduced, the working condition adaptability is improved, and the production efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 is a fastening control system block diagram provided by an embodiment of the present application;

[0010] Figure 2 is a control flow diagram of a fastening logic module provided by an embodiment of the present application;

[0011] Figure 3 is a chuck position record diagram of an electric tool provided by an embodiment of the present application;

[0012] Figure 4 is a fastening process diagram when the initial state of a screw or nut is not fitted when provided by an embodiment of the present application;

[0013] Figure 5 is a fastening process diagram when the initial state of a screw or nut is fitted when provided by an embodiment of the present application;

[0014] Figure 6 is another control flow diagram of a fastening logic module provided by an embodiment of the present application;

[0015] Figure 7 is still another control flow diagram of a fastening logic module provided by an embodiment of the present application;

[0016] Figure 8 is a fastening control method diagram provided by an embodiment of the present application.

[0017] The implementation, functional features and advantages of the present application will be further described with reference to the accompanying drawings in conjunction with embodiments. DETAILED DESCRIPTION

[0018] In order to make the technical problems, technical solutions and beneficial effects of the present application more clear, specific embodiments will be further described in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0019] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0020] The variables involved in the embodiments of the present application and their definitions are as follows:

[0021] Torque target value

[0022] Speed limit target value

[0023] Fitting torque set value

[0024] Torque change amount detection threshold value

[0025] Fastening speed set value

[0026] Minimum rotation speed set value

[0027] T tool : Torque on the chuck

[0028] θ tool : Rotation angle on the chuck

[0029] ω tool : Rotation speed on the chuck

[0030] Speed limit set value on the chuck

[0031] Torque set value on the chuck

[0032] Speed limit set value of the motor

[0033] Torque set value of the motor

[0034] Torque set effective value of the motor

[0035] T motor : Torque of the motor

[0036] ω motor : Rotation speed of the motor

[0037] θ motor : Rotation angle of the motor

[0038] ΔT: Speed limit torque adjustment amount

[0039] Excitation current set value of the motor

[0040] i sd : Excitation current detection value of the motor

[0041] Torque current set value of the motor

[0042] i sq: torque current detection value of motor

[0043] Figure 1 is a control block diagram of the electric tool provided by the embodiment of the application.

[0044] As shown in Figure 1 , the electric tool comprises a power module, a motor driving module, a motor, a speed reducer and a chuck. The motor driving module is connected with the power module, and the motor driving module is used to drive the motor and the speed reducer to work, so as to fasten the screw or nut when the chuck contacts with the screw or nut.

[0045] The rotational speed ω motor of the motor can be obtained by the speed detection module, and the rotational speed ω tool (speed detection value) on the chuck is obtained after the mechanical variable ratio is scaled and converted. motor The rotational angle θ tool (position detection value) on the chuck is obtained after the mechanical variable ratio is scaled and converted. tool The torque T tool (torque detection value) on the chuck can be obtained by the torque detection module.

[0046] The control system of the electric tool comprises a fastening logic module, a speed limiting module and a motor control module.

[0047] The input configuration parameters of the fastening logic module comprise: a torque target value a speed limiting target value a fitting torque setting value a torque change amount detection threshold a fastening speed setting value a minimum rotating speed setting value

[0048] The fastening logic module adjusts the output torque setting value and the speed limiting setting value on the chuck according to the torque T tool , the rotational speed ω tool and the rotational angle θ tool on the chuck.

[0049] The torque setting value on the chuck is scaled and converted to obtain the torque setting value of the motor. The speed limiting setting value on the chuck is scaled and converted to obtain the speed limiting setting value of the motor.

[0050] The speed limiting module includes a speed limiting regulator. During the tightening process, the motor operates in torque control mode, and the speed limiting regulator limits the maximum speed of the motor during torque control. Specifically, if the motor rotational speed ω motor Greater than the motor speed limit setting value The motor rotational speed ω is controlled by adjusting the magnitude of the speed limit torque adjustment amount ΔT. motor Less than or equal to the motor speed limit setting value

[0051] Motor control modules include common modules such as current detection modules, coordinate transformation modules, current loop regulators, PWM drive modules, etc. The motor control module sets the effective values ​​based on the motor's torque. Control the motor to output the corresponding torque value. Among them, Specifically, the effective value of the motor torque setting. The torque and current setpoints of the motor are obtained after calibration and conversion. The current loop regulator is based on the motor's torque current setpoint. Motor torque current detection value i sq The excitation current setting value of the motor and the excitation current detection value i of the motor sd It outputs control commands; after being modulated by the PWM drive module, it outputs drive signals to control the motor drive module, thereby driving the motor.

[0052] Figure 2 This is a schematic diagram of the control flow of the fastening logic module provided in the embodiments of this application.

[0053] After the power tool comes into contact with the screw or nut, the speed limit setting on the batch head is gradually increased according to the preset process curve 1. Until the speed limit target value Gradually increase the torque setting value on the batch head according to the preset process curve 2. Until the target torque value Preset process curve 1 and preset process curve 2 are not limited here.

[0054] Under the action of the speed limiting module, if the motor rotation speed ω motor Greater than the motor speed limit setting value Then the torque setting value on the screwdriver bit Keep it at the current value; if the motor rotation speed ω motor Less than or equal to the speed limit value Then the torque setting value on the screwdriver bit Gradually increase to the target torque value

[0055] If the torque T on the bittool greater than the engagement torque set value and the rotational speed ω of the chuck on the electric tool is greater than the fastening speed set value tool greater than or equal to the engagement torque set value if the screw or nut is determined to be close to engagement, the drive motor immediately outputs a brake torque to reduce the speed to the minimum rotational speed set value to prevent the engagement speed from being too large to cause torque overshoot; and limit the speed of the chuck to the target value torque set value clear, and the fastening process restarts.

[0056] if the torque T of the chuck tool is greater than the engagement torque set value and the rotational speed ω of the chuck on the electric tool is greater than the fastening speed set value tool is less than or equal to the engagement torque set value if the screw or nut is determined to have been engaged, the drive motor continues to increase the torque set value of the chuck when the torque T of the chuck tool reaches the torque target value , the fastening process ends.

[0057] engagement torque set value fastening speed set value The fastening speed set value needs to be determined according to the torque control accuracy of the electric tool and the process specification of the screw or nut. In an example,

[0058] if the torque T of the chuck tool is less than or equal to the engagement torque set value if the screw or nut is determined to have not been engaged, the speed of the chuck is limited to the speed limit set value and continues to run.

[0059] record the torque detection value T of the motor at different rotational angles tool , and calculate the change amount of the torque detection value at the same rotational angle; determine whether the change amount of the torque detection value is greater than the torque change amount detection threshold if the torque change amount is greater than the torque change amount detection threshold if the screw or nut is determined to be close to engagement, the drive motor immediately outputs a brake torque to reduce the speed to the minimum rotational speed set value to prevent the engagement speed from being too large to cause torque overshoot; and limit the speed to the target value torque set value clear, and the fastening process restarts.

[0060] In an example, as Figure 3 shown, the chuck position 0-360 degrees of the electric tool can be divided into 64 points for recording, as shown in the following table:

[0061] Mechanical angle Torque detection value Last turn torque detection value 0° TorqAct[0] TorqBak[0] 5.625° TorqAct[1] TorqBak[1] 11.25° TorqAct[2] TorqBak[2] …… …… …… 354.375° TorqAct

[62] TorqBak

[62] 360° TorqAct

[63] TorqBak

[63]

[0062] torque variation detection threshold Related to the mechanical accuracy of the power tool and the torque sensor detection accuracy, in an example, = 200 mNm.

[0063] The control process of the fastening logic module can reduce the configuration parameters, and the process curve is selected as a straight line, only the slope of the speed limit target value and the slope of the torque set value need to be configured, and the torque set value fastening speed set value torque variation detection threshold and other parameters.

[0064] The control process of the fastening logic module can adapt to different initial states of screws or nuts. If the initial state of the screw or nut is not fitted, the entire fastening process is as shown in Figure 4 If the initial state of the screw or nut has been fitted, the entire fastening process is as shown in Figure 5 .

[0065] The control process of the fastening logic module has no restrictions on the type of motor control algorithm and the type of driving motor, as long as the output torque of the motor can be controlled to meet the requirements. For some special application occasions, when the torque T tool on the chuck reaches the torque target value , special logic processing can be performed, for example, the torque set value on the chuck is maintained for a period of time before the fastening process is ended, as shown in Figure 6 ; after the torque set value on the chuck reaches the torque target value , the chuck is rotated by a fixed angle before the fastening process is ended, as shown in Figure 7 .

[0066] Figure 8 is a fastening control method provided by an embodiment of the application.

[0067] As shown in Figure 8 , the fastening control method comprises the steps of:

[0068] S11, increasing the speed limit set value and the torque set value on the chuck;

[0069] S12, adjusting the speed limit set value and the torque set value on the chuck according to the torque detection value, the speed detection value and the position detection value.

[0070] In an example, the method further comprises:

[0071] If the motor rotation speed is greater than the speed limit setting value of the motor, the size of the speed limit torque adjustment amount is adjusted to control the motor rotation speed to be less than or equal to the speed limit setting value of the motor.

[0072] In an example, the method further comprises:

[0073] If the motor rotation speed is greater than the speed limit setting value of the motor, the torque setting value on the chuck remains the current value; if the motor rotation speed is less than or equal to the speed limit setting value of the motor, the torque setting value on the chuck is increased.

[0074] In an example, the adjusting the output of the speed limit setting value and the torque setting value on the chuck according to the torque detection value, the speed detection value, and the position detection value comprises:

[0075] If the torque detection value is greater than the fitting torque setting value and the speed detection value is greater than or equal to the tightening speed setting value, the motor is driven to output a brake torque to decelerate to a minimum rotation speed setting value while the speed limit setting value and the torque setting value on the chuck are cleared.

[0076] In an example, the adjusting the output of the speed limit setting value and the torque setting value on the chuck according to the torque detection value, the speed detection value, and the position detection value comprises:

[0077] If the torque detection value is greater than the fitting torque setting value and the speed detection value is less than the tightening speed setting value, the motor is driven to continue to increase the torque setting value on the chuck.

[0078] When the torque detection value reaches the torque target value, the tightening process is ended.

[0079] In an example, when the torque detection value reaches the torque target value, the torque setting value on the chuck is maintained for a preset time value before the tightening process is ended.

[0080] In an example, when the torque detection value reaches the torque target value, the tightening process is ended after rotating a preset angle value.

[0081] In an example, the adjusting the output of the speed limit setting value and the torque setting value on the chuck according to the torque detection value, the speed detection value, and the position detection value comprises:

[0082] If the torque detection value is less than or equal to the fitting torque setting value, the speed limit setting value on the chuck is continued to run.

[0083] The torque detection values at different rotation angles of the motor are recorded, and the change amount of the torque detection values at the same rotation angle is calculated.

[0084] If the variation of the torque detection value at the same rotation angle is greater than the torque variation detection threshold, the driving motor outputs a brake torque to decelerate to a minimum rotation speed setting value, while the speed limit setting value and the torque setting value on the chuck are cleared.

[0085] In an example, the method further comprises:

[0086] The torque detection value is recorded at a preset number of recording points from 0 to 360 degrees of the chuck position of the power tool.

[0087] In an example, the increasing the speed limit setting value and the torque setting value on the chuck comprises:

[0088] The speed limit setting value on the chuck is increased by a first preset process curve until a speed limit target value, and the torque setting value on the chuck is increased by a second preset process curve until a torque target value.

[0089] Further, the embodiments of the present application also provide a fastening control device, comprising a processor and a memory, the memory stores at least one program code, the at least one program code is loaded and executed by the processor to implement the fastening control method described above.

[0090] The fastening control device may be the power tool described above.

[0091] Further, the embodiments of the present application also provide a computer readable storage medium, the computer readable storage medium stores at least one program code, the at least one program code is loaded and executed by the processor to implement the fastening control method described above.

[0092] The preferred embodiments of the present application are described above with reference to the accompanying drawings, and are not intended to limit the scope of the present application. Any modifications, equivalent replacements and improvements made by those skilled in the art without departing from the scope and essence of the present application shall fall within the scope of the present application.

Claims

1. A method for fastening a power tool, the power tool comprising a motor and a screwdriver bit; characterized in that, The method includes: Increase the speed limit setting and torque setting on the batch head; Based on the torque detection value, speed detection value, and position detection value, adjust and output the speed limit setting value and torque setting value on the bit; The step of adjusting and outputting the speed limit setting and torque setting value on the screwdriver head based on the torque detection value, speed detection value, and position detection value includes: If the detected torque value is less than or equal to the set contact torque value, the machine continues to operate at the speed limit set value on the bit. Record the torque detection values ​​of the motor at different rotation angles, and calculate the change in torque detection values ​​at the same rotation angle; If the change in the torque detection value under the same rotation angle is greater than the torque change detection threshold, the drive motor outputs braking torque to decelerate to the minimum speed setting value, and at the same time, the speed limit setting value and torque setting value on the bit are cleared to zero.

2. The method according to claim 1, characterized in that, The method further includes: If the motor rotation speed is greater than the motor speed limit setting value, the speed limit torque adjustment amount is adjusted to control the motor rotation speed to be less than or equal to the motor speed limit setting value.

3. The method according to claim 1, characterized in that, The method further includes: If the motor rotation speed is greater than the motor speed limit setting value, the torque setting value on the bit will remain at the current value; If the motor rotation speed is less than or equal to the motor speed limit setting, then increase the torque setting on the bit.

4. The method according to claim 1, characterized in that, The step of adjusting and outputting the speed limit setting and torque setting value on the screwdriver head based on the torque detection value, speed detection value, and position detection value includes: If the torque detection value is greater than the fitting torque setting value and the speed detection value is greater than or equal to the tightening speed setting value, then drive the motor to output braking torque to decelerate to the minimum speed setting value, and at the same time clear the speed limit setting value and torque setting value on the bit to zero.

5. The method according to claim 1, characterized in that, The step of adjusting and outputting the speed limit setting and torque setting value on the screwdriver head based on the torque detection value, speed detection value, and position detection value includes: If the torque detection value is greater than the contact torque setting value and the speed detection value is less than the fastening speed setting value, then drive the motor to continue increasing the torque setting value on the bit. The tightening process ends when the detected torque value reaches the target torque value.

6. The method according to claim 5, characterized in that, When the torque detection value reaches the torque target value, the tightening process ends after the torque setting value on the bit is maintained for a preset time.

7. The method according to claim 5, characterized in that, When the torque detection value reaches the torque target value, the tightening process ends after rotating by a preset angle value.

8. The method according to claim 1, characterized in that, The method further includes: The bit position of the power tool is divided into a preset number of recording points from 0 to 360 degrees to record the torque detection value.

9. The method according to claim 1, characterized in that, The speed limit setting and torque setting on the increased batch head include: The speed limit setting on the bit is increased using a first preset process curve until the speed limit target value is reached; the torque setting on the bit is increased using a second preset process curve until the torque target value is reached.

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