CN115113653A - Control method for searching thread cutting-in origin of intelligent servo electric gun - Google Patents
Control method for searching thread cutting-in origin of intelligent servo electric gun Download PDFInfo
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- CN115113653A CN115113653A CN202210633428.4A CN202210633428A CN115113653A CN 115113653 A CN115113653 A CN 115113653A CN 202210633428 A CN202210633428 A CN 202210633428A CN 115113653 A CN115113653 A CN 115113653A
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- 238000000034 method Methods 0.000 title claims abstract description 29
- 238000001514 detection method Methods 0.000 claims abstract description 15
- 238000012544 monitoring process Methods 0.000 claims abstract description 11
- 230000000737 periodic effect Effects 0.000 claims description 2
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
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- 238000012797 qualification Methods 0.000 description 2
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D3/00—Control of position or direction
- G05D3/12—Control of position or direction using feedback
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
- B25B21/00—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose
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- General Physics & Mathematics (AREA)
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- Details Of Spanners, Wrenches, And Screw Drivers And Accessories (AREA)
Abstract
The invention discloses a control method for searching a thread cutting-in original point of an intelligent servo electric gun, wherein the intelligent servo electric gun comprises a servo motor, an output shaft, a controller, a rotary encoder and a torque detection device; the servo motor is provided with a rotary encoder for monitoring the rotary pose angle of the output shaft of the servo motor in real time and transmitting the rotary angle pose data to the controller; the servo motor is provided with a torque detection device which is used for monitoring the output torque of the output shaft of the servo motor in real time and transmitting the torque value to the controller; the control method can find and record the angle position of the cutting origin point of the bolt matched with the thread, and comprises the following steps: recording the time point of the falling edge of the sudden change of the torque from large to small, and setting the angle position of the output shaft corresponding to the time point as a cut-in origin; the controller instructs the servo motor to brake and stop. The invention has the beneficial effects that: the cutting origin between the bolt and the thread can be found, which is a precondition for achieving the angle control.
Description
Technical Field
The invention belongs to the technical field of intelligent servo electric guns, and particularly relates to a control method.
Background
Bolt tightening on the production line is automatically completed through an intelligent servo electric gun, manual work is replaced, and work efficiency is improved. The automatic premise is that the bolt is standardized, the length of the bolt is controlled within a certain error range, and then the bolt is screwed up according to a set angle or torque through an intelligent servo electric gun.
In some occasions with special requirements, for example, two conducting strips in a high-protection electric meter need to be tightly pressed by bolts. The product requires that no gap can be formed between the two conducting strips, because once the gap exists, electric sparks can be generated in the using process to generate heat, and the heat finally can cause the damage of the whole ammeter, the explosion of serious people and major accidents. This requires that the assembly requirements for the bottom screwing of the bolt be strictly met on an automatic production line.
At present, most intelligent electric guns on the market have multiple screwing control modes, and most of the existing control modes are screwing torque and angle monitoring modes aiming at screw screwing. The problem can be accurately found out by monitoring whether the angle is within the range of the tightening angle while the tightening torque is achieved, and if the M6 20 turns, the torque is achieved, the tightening obviously floats, but the problem that the torque is achieved but the difference is 0.1-0.5 mm in fit is not effectively controlled.
The reason for the problems is found by analysis, and the current intelligent servo electric guns do not have the function of searching for a bolt tightening cut-in original point. When the bolt and the nut are screwed, a thread entry point is formed, and when the bolt is screwed, the entry point is found only after idling for a certain angle because of different poses of the bolt, and then the bolt is really screwed in. The rotation angle of the entry point found before is different due to different initial poses of the bolts with randomness. Since the current intelligent servo electric gun has no function of searching for the original point or does not provide the concept of the original point (namely the entry point), the angle control cannot be mentioned in the process of screwing the bolt.
Disclosure of Invention
Aiming at the problem that the intelligent servo electric gun does not have the function of searching the original point in the prior art, the control method for searching the thread cut-in original point by the intelligent servo electric gun is provided.
A control method for searching a thread cutting-in original point of an intelligent servo electric gun comprises the steps that the intelligent servo electric gun comprises a servo motor, an output shaft, a controller, a rotary encoder and a torque detection device;
the servo motor is provided with a rotary encoder for monitoring the rotary pose angle of the output shaft of the servo motor in real time and transmitting the rotary angle pose data to the controller;
the servo motor is provided with a torque detection device which is used for monitoring the output torque of the output shaft of the servo motor in real time and transmitting the torque value to the controller;
the controller is used for controlling the servo motor to work;
after an output shaft of the servo motor is matched with the bolt, the bolt is aligned with the center of the threaded hole, so that the lower end of the bolt is tightly propped against the upper surface of the screw hole;
the control method can find and record the angle position of the cutting origin point of the bolt matched with the thread, and comprises the following steps:
s1, the controller instructs the servo motor to rotate reversely, and monitors the rotation angle and the output torque of the output shaft of the servo motor in the reverse rotation process in real time;
s2, recording the time point of the falling edge of the sudden change of the torque from big to small, and setting the angle position of the output shaft corresponding to the time point as a cut-in origin;
s3: the controller instructs the servo motor to brake and stop.
In the process that the bolt rotates reversely in the threaded hole, a descending edge which is suddenly changed from large to small is generated in the torque value range period of the output shaft of the servo electric gun, and the time point of the second or third descending edge of the periodic torque is selected to be recorded in step S3.
In step S2, the reverse rotation speed is 100 rpm.
The invention has the beneficial effects that: the cutting origin between the bolt and the thread can be found, which is a precondition for achieving the angle control.
Drawings
FIG. 1 is a schematic diagram of an intelligent servo electric gun;
FIG. 2 is a schematic diagram of the torque variation state of the output shaft of the electric gun monitored by the torque detection device;
fig. 3 is a schematic view of a bolt.
Detailed Description
In order to make the technical problems solved, the technical solutions adopted and the technical effects achieved by the present invention clearer, the technical solutions of the present invention are further described below by way of specific embodiments with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some but not all of the elements associated with the present invention are shown in the drawings.
First, the method of the present invention requires standardized bolts of uniform length. Second, it is also desirable to have a standardized depth for the threaded hole to be screwed in. Thus, the number of turns until the bolt is tightened is determined for each bolt as calculated from the cutting origin of the thread. As long as the cutting origin of the thread can be accurately found, the bolt is screwed down according to the set number of turns, and the accurate control of the angle can be achieved.
Meaning with respect to the thread run-in origin. As shown in fig. 3, the thread of the bolt follows a continuous spiral with the start of the thread at the lowermost side of the thread. Similarly, the internal thread follows a continuous helix with its start at the uppermost end of the internal threaded bore. When the thread starting end of the bolt meets the starting end of the internal thread hole, the bolt is screwed into the internal thread hole continuously. The control method of the present invention aims to find the thread run-in origin.
As shown in FIG. 1, the intelligent servo electric gun system comprises a servo motor, an output shaft, a controller, a rotary encoder and a torque detection device. And the servo motor is provided with a rotary encoder for monitoring the rotary pose angle of the output shaft of the servo motor in real time and transmitting the rotary angle pose data to the controller. The servo motor is provided with a torque detection device for monitoring the output torque of the output shaft of the servo motor in real time and transmitting the torque value to the controller. The controller is used for controlling the servo motor to work.
The torque detection device can be an external torque detection sensor; the torque output value can also be converted by a detection device arranged in the servo motor according to the magnitude of the feedback current of the servo motor. Other, common torque sensing devices are also included.
In fig. 1, the output shaft of the servomotor has a tool head for screwing a bolt, such as a cross head, a hexagon socket head, etc., which can be matched with the bolt.
A control method for finding a thread cut-in original point of an intelligent servo electric gun is characterized in that after an output shaft of a servo motor is matched with a bolt, the bolt is aligned with the center of a threaded hole, the lower end of the bolt is tightly propped against the upper surface of the threaded hole, a controller instructs the servo motor to rotate reversely at the rotating speed of 100 revolutions per minute, and the rotating angle of the output shaft of the servo motor and the output torque in the reverse rotating process are monitored in real time.
In the process of reverse rotation, the threads at the lower end of the bolt rotate on the threads in the threaded hole, the highest point of the height reached by the bolt is the time when the thread starting end at the lower end of the bolt is in contact with the thread starting end of the threaded hole, reverse rotation is continued, and the bolt can slide to the lowest point from the highest point. We call this process from highest to lowest point a jump. With each 360 degrees of inversion, there will be one beat. During reverse rotation, torque monitoring of the output shaft reveals that each time a jump occurs, a falling edge in torque is produced.
As shown in fig. 2, the abscissa represents the time axis and the ordinate represents the torque value, and t1 to t5 represent the falling edges corresponding to five torques respectively, which are the torque detection results during the inversion.
In the process, the controller records the time of the next falling edge, for example, t2, and then records the angle value of the output shaft recorded by the rotary encoder at the time corresponding to t2, and sets the rotation angle of the output shaft at the time as the cutting origin.
In the actual working process, in order to accurately capture the falling edge, the rotation is performed for 2 turns, that is, when the 2 nd falling edge is detected, the corresponding rotation angle of the output shaft at the 2 nd falling time is taken as the cut-in origin. When the 2 nd falling edge is monitored, the controller records the cut-in origin and then commands the servo motor to brake and stop rotating.
The controller instructs the servo motor to rotate forward to the angle position of the cut-in origin, and the servo motor rotates forward again by the set angle starting at the position of the origin. The set rotation angle is calculated in advance according to the length of the bolt, for example, 5 × 360 degrees, or 6 × 360 degrees +30 degrees.
After the servo motor is screwed to a specified angle position, the torque detection device detects whether the torque of the output shaft of the servo motor reaches a preset value or not, if yes, the servo motor is considered to be a qualified product, and if not, the servo motor is considered to be an unqualified product.
Through angle control and the control of moment of torsion size like this, two aspects are monitored the process of screwing up of bolt, guarantee that the bolt screws up to the end, and the clearance reaches technical tolerance's requirement, guarantees the qualification of product, rejects the defective products.
In addition, the control mode can be added with a self-checking mode. When the intelligent servo electric gun screws the bolt to a specified angle and simultaneously reaches a set torque, the servo electric gun is instructed to rotate reversely by a certain angle, for example, 360 degrees, and then rotates forward by the same angle, whether the set angle value and the set torque value are simultaneously reached is detected again, if the set angle value and the set torque value are reached, a qualified product is considered, if the set angle value and the set torque value are not reached, an unqualified product is considered, one-time detection of the product is completed, and the qualification rate of the product is further ensured.
In the description of the invention, the motor rotates reversely and forwardly, and the rotation direction of the screw thread is referred to as the rotation direction of the object. During forward rotation, the threads can be matched and screwed, and during reverse rotation, the threads can be loosened.
In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "clockwise" and "counterclockwise" and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.
The foregoing embodiments are merely illustrative of the principles and features of this invention, which is not limited to the above-described embodiments, but rather is susceptible to various changes and modifications without departing from the spirit and scope of the invention, which changes and modifications are within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (4)
1. A control method for searching a thread cutting-in original point of an intelligent servo electric gun comprises the steps that the intelligent servo electric gun comprises a servo motor, an output shaft, a controller, a rotary encoder and a torque detection device;
the servo motor is provided with a rotary encoder for monitoring the rotary pose angle of the output shaft of the servo motor in real time and transmitting the rotary angle pose data to the controller;
the servo motor is provided with a torque detection device which is used for monitoring the output torque of the output shaft of the servo motor in real time and transmitting the torque value to the controller;
the controller is used for controlling the servo motor to work;
after an output shaft of the servo motor is matched with the bolt, the bolt is aligned with the center of the threaded hole, so that the lower end of the bolt is tightly propped against the upper surface of the screw hole;
the control method is characterized in that the control method can find and record the angle position of the cutting origin point of the bolt matched with the thread, and comprises the following steps:
s1, the controller instructs the servo motor to reverse, and monitors the rotation angle and the output torque of the output shaft of the servo motor in the reverse process in real time;
and S2, recording the time point of the falling edge of the abrupt change of the torque from large to small, and setting the angle position of the output shaft corresponding to the time point as a cut-in origin.
2. The control method for finding the thread cutting origin point of the intelligent servo electric gun as claimed in claim 1, further comprising the step of S3: the controller instructs the servo motor to brake and stop.
3. The control method for finding the thread cutting origin point of the intelligent servo electric gun as claimed in claim 2, wherein during the process that the bolt is reversed in the threaded hole, the torque value of the output shaft of the servo electric gun periodically generates a descending edge with a sudden change from large to small, and step S3 selects the time point of the second or third descending edge of the periodic torque for recording.
4. The control method for finding the cutting origin of the screw thread by the intelligent servo electric gun as claimed in claim 1, wherein the reverse rotation speed in step S2 is 100 rpm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210633428.4A CN115113653A (en) | 2022-06-07 | 2022-06-07 | Control method for searching thread cutting-in origin of intelligent servo electric gun |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210633428.4A CN115113653A (en) | 2022-06-07 | 2022-06-07 | Control method for searching thread cutting-in origin of intelligent servo electric gun |
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| CN115113653A true CN115113653A (en) | 2022-09-27 |
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| CN202210633428.4A Pending CN115113653A (en) | 2022-06-07 | 2022-06-07 | Control method for searching thread cutting-in origin of intelligent servo electric gun |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106709077A (en) * | 2015-07-16 | 2017-05-24 | 北京福田康明斯发动机有限公司 | Bolt tightening equipment and method and bolt tightening monitoring system and method |
| CN107234425A (en) * | 2016-03-28 | 2017-10-10 | 博世华域转向系统（烟台）有限公司 | A kind of control method of component assembly bolt and nut screw-down torque |
| CN109489953A (en) * | 2018-12-03 | 2019-03-19 | 江西洪都航空工业集团有限责任公司 | A kind of logical only detection machine of High Precision Automatic screw thread |
| CN211121711U (en) * | 2019-11-25 | 2020-07-28 | 广东英达思迅智能制造有限公司 | Micromotor torque testing equipment |
| CN111645019A (en) * | 2020-05-29 | 2020-09-11 | 杭州琪晖建筑设计有限公司 | Novel high-strength bolt electric inspection wrench and screwing process |
-
2022
- 2022-06-07 CN CN202210633428.4A patent/CN115113653A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106709077A (en) * | 2015-07-16 | 2017-05-24 | 北京福田康明斯发动机有限公司 | Bolt tightening equipment and method and bolt tightening monitoring system and method |
| CN107234425A (en) * | 2016-03-28 | 2017-10-10 | 博世华域转向系统（烟台）有限公司 | A kind of control method of component assembly bolt and nut screw-down torque |
| CN109489953A (en) * | 2018-12-03 | 2019-03-19 | 江西洪都航空工业集团有限责任公司 | A kind of logical only detection machine of High Precision Automatic screw thread |
| CN211121711U (en) * | 2019-11-25 | 2020-07-28 | 广东英达思迅智能制造有限公司 | Micromotor torque testing equipment |
| CN111645019A (en) * | 2020-05-29 | 2020-09-11 | 杭州琪晖建筑设计有限公司 | Novel high-strength bolt electric inspection wrench and screwing process |
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