CN107843368B

CN107843368B - Economical and practical stepping motor pulling torque characteristic automatic testing device

Info

Publication number: CN107843368B
Application number: CN201711071307.0A
Authority: CN
Inventors: 葛元月; 熊亚; 庞军; 吕小莲; 崔平安
Original assignee: Chuzhou University
Current assignee: Chuzhou University
Priority date: 2017-11-03
Filing date: 2017-11-03
Publication date: 2020-07-17
Anticipated expiration: 2037-11-03
Also published as: CN107843368A

Abstract

The invention discloses an economical and practical automatic testing device for the traction torque characteristics of a stepping motor, which comprises the stepping motor to be tested, a torque loading measuring device and a control system, wherein the stepping motor to be tested is arranged on a platform, the torque loading measuring device is connected with a left half shaft and a motor, and the control system consists of a single chip microcomputer and a driver. The right half shaft of the torque loading measuring device is fixedly connected to the support through the connector, the torsion spring is connected to the right half shaft in a sleeved mode, the left end of the torsion spring is fixedly connected to a fixing hole of the left half shaft, and the thrust bolt fixedly connected to the right half shaft is loaded through the right end of the torsion spring. An encoder mounted on the left half shaft detects the angle of rotation of the left half shaft relative to the right half shaft and is translated into a load torque by the control system. The two singlechips of the control system cooperate to read and control the position, the speed and the movement direction of the motor and judge whether the motor loses steps. The main control program can start the test, read and control the single chip microcomputer, and automatically store the test data. The invention has simple structure and low cost, can complete all tests by one key and has simple operation.

Description

Economical and practical stepping motor pulling torque characteristic automatic testing device

Technical Field

The invention relates to a testing device, belongs to the technical field of mechanical and electronic measurement, and particularly relates to an economical and practical automatic testing device for emigration torque characteristics of a stepping motor.

Background

At present, the application field of the stepping motor is more and more extensive, and the stepping motor is generally applied to the industries of machinery, electronics, textile and the like. Such as a 3D printer.

When the torque and speed of the stepper motor are not enough to overcome the load, the stepper motor will run out of step. That is, the number of steps in operation of the motor is not equal to the number of steps in theoretical control, and is called step loss. This causes inaccurate control, and therefore, in many cases, an additional angle measuring device is required to measure the angle or speed of the stepping motor.

If the output characteristic curve of the pulling-out torque of the stepping motor can be obtained, the stepping motor can be controlled to work under the rated speed torque, the control accuracy is ensured, and the complexity of the system is reduced. Therefore, it is necessary to measure the torque characteristics of the stepping motor.

Some current methods for measuring the torque characteristics of the stepping motor are too complicated, and some methods are too complex to cause higher cost. Some simple structure of torque measurement structure in the past, but complex operation, for example common one traditional measurement mode is hung the heavy object on step motor, and the biggest heavy object that the motor can be lifted can be turned into the maximum torque. Yet another method is based on an improvement of the former measuring method, i.e. using the principle of leverage, the length of the lever is changed without changing the weight of the weight. Both of these methods are relatively simple in construction and operation, but require a large number of manual repeated measurements, constantly changing loads and speeds. However, the currently designed stepping motor torque measuring devices with simple operation all have the problems of complicated structure and high price, such as the automobile air conditioner stepping motor torque output characteristic measuring system (chinese patent application No.: CN201410426069) in patent document 1 and the motor torque testing device (chinese patent application No. (CN201610415120) in patent document 2.

Disclosure of Invention

The invention provides an economical and practical measuring device for a pull-out torque output characteristic curve aiming at the difficult problem of measurement of the pull-out torque output characteristic.

The torque measuring device of the invention simply and skillfully completes the measurement of the torque characteristic of the stepping motor, thus having low cost and simple structure. And the testing process is completely and automatically completed, the maximum pulling-out torque under different loads is obtained, and a pulling-out torque characteristic curve can be automatically drawn.

The invention adopts the following technical scheme:

an economical and practical automatic testing device for the traction torque characteristics of a stepping motor comprises a mechanical device and a control system, wherein the mechanical device comprises the stepping motor to be tested, the stepping motor to be tested is fixedly connected with a motor support through a bolt, the motor support is fixedly arranged on a bottom plate, an output shaft of the stepping motor to be tested is fixedly connected with one end of a coupler, the other end of the coupler is fixedly connected with a torque loading and measuring mechanism, a hollow encoder is fixedly arranged on a left half shaft of the torque loading and measuring mechanism, a detection part of the hollow encoder is fixedly arranged on the bottom plate through an encoder support, the left half shaft and a right half shaft of the torque loading and measuring mechanism are respectively arranged on a left support and a right support through bearings and connectors, the left support and the right support are respectively and sequentially fixedly connected onto the bottom plate, a stepping motor driver, a single chip microcomputer and a single chip microcomputer are respectively and sequentially and fixedly arranged on the bottom plate, the connectors and the right support are fixedly connected through fixing pins, and the control system comprises a single chip microcomputer, a second single chip microcomputer and.

Further, the torque loading and measuring mechanism is characterized in that the right end of the right half shaft is fixedly connected with the connector through a fixedly connected pin and a pin hole, the left end of the right half shaft is mounted on the left half shaft integrally through a closed cover and a left half shaft hole, the left half shaft integrally can rotate with the right half shaft, the torsion spring sleeve is connected to the right half shaft, the left end of the torsion spring is fixedly connected to a torsion spring fixing hole of the left half shaft, and the thrust bolt fixedly connected to the right half shaft pushes the right end of the torsion spring to rotate to load through mutual rotation of the two half shafts.

The single chip microcomputer is used for detecting the index position of the motor, controlling the movement speed of the motor, changing the movement direction of the motor and communicating with the MAT L AB and the single chip microcomputer II, and the single chip microcomputer II is used for reading signals of the encoder, calculating the running speed of the current encoder, comparing and judging whether the motor loses steps according to the signals of the encoder and control signals of the motor and communicating with the MAT L AB and the single chip microcomputer I.

Further, the MAT L AB control system is used for starting the whole automatic test system by sending control signals to the two singlechips, reading speed and position signals of the encoder from the singlechips of the encoder, calculating torsion spring torque according to the position of the encoder, and automatically storing motion data and drawing a torque characteristic curve of the stepping motor when each test is finished.

Compared with the prior art, the invention has the beneficial effects that: the invention designs an economical and practical automatic testing device for the pulling-out torque characteristic of a stepping motor, which comprises a device based on a torque spring and an encoder and integrates torque loading, torque measurement, step loss measurement and speed measurement. Compared with the conventional torque characteristic measuring device, the measuring device has the advantages of simple structure and low cost. The invention can automatically complete the whole testing process by clicking the start key, including loading and changing the torque, measuring the torque and drawing the final characteristic curve, and the whole testing process is completed in one step. Therefore, the invention solves the problems of complex operation or high cost of the traditional torque characteristic measuring mechanism, and achieves simple operation and low cost. The whole test is completed by one click, and the method is simple, convenient and quick.

Drawings

Fig. 1 is a schematic structural diagram of a stepping motor torque characteristic testing device according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a torque loading and measuring mechanism provided in an embodiment of the present invention;

fig. 3 is a schematic front view of a torque characteristic testing apparatus for a stepping motor according to an embodiment of the present invention;

fig. 4 is a schematic top view of a torque characteristic testing apparatus for a stepping motor according to an embodiment of the present invention;

FIG. 5 is a two-dimensional engineering drawing of a torque loading and measuring mechanism provided by an embodiment of the present invention;

FIG. 6 is a logic block diagram of a control system provided by an embodiment of the present invention;

FIG. 7 is a flowchart of the MAT L AB control logic provided by an embodiment of the present invention;

FIG. 8 is a motion logic diagram for a single test cycle of a stepper motor provided in accordance with an embodiment of the present invention;

fig. 9 is a control logic flow diagram of the first single chip microcomputer according to the embodiment of the present invention;

fig. 10 is a control logic flow chart of the second single chip microcomputer provided in the embodiment of the present invention.

In the figure: 1: a base plate; 2: a stepper motor to be tested; 3: a motor bracket; 4: a coupling; 5: a hollow encoder; 6: an encoder support; 7: a torque loading and measuring mechanism; 7-1: the left half shaft is integral; 7-2: a torsion spring; 7-3: a closure cap; 7-4: a pin hole; 7-5: a right half shaft; 7-6: a thrust bolt; 7-7: a torsion spring fixing hole; 7-8: a left half axle shaft hole; 8: a left bracket; 9: a right bracket; 10: a bearing; 11: a stepper motor driver; 12: a single chip microcomputer; 13: a second singlechip; 14: fixedly connecting a pin; 15: a connector is provided.

Detailed Description

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.

The device for automatically testing the torque characteristics pulled out by the stepping motor is characterized by comprising a mechanical device and a control system, wherein the mechanical device comprises a stepping motor 2 to be tested, the stepping motor 2 to be tested is fixedly connected with a motor support 3 through a bolt, the motor support 3 is fixedly installed on a bottom plate 1, an output shaft of the stepping motor 2 to be tested is fixedly connected with one end of a coupler 4, the other end of the coupler 4 is fixedly connected with a torque loading and measuring mechanism 7, a hollow encoder 5 is fixedly installed on a left half shaft of the torque loading and measuring mechanism 7, a detection part of the hollow encoder 5 is fixedly installed on the bottom plate 1 through an encoder support 6, a left half shaft and a right half shaft of the torque loading and measuring mechanism 7 are respectively installed on a left support 8 and a right support 9 through a bearing 10 and a connector 15, the left support 8 and the right support 9 are respectively and fixedly connected to the bottom plate 1 in sequence, a stepping motor driver 11, a first singlechip 12 and a second singlechip 13 are respectively and fixedly installed on the bottom plate 1, the connector 15 and the right support 9 are fixedly connected through a pin 14, and the control system comprises a first singlechip L, a second singlechip 12 and a second singlechip 26.

Further, the torque loading and measuring mechanism 7 is characterized in that the right end of a right half shaft 7-5 is fixedly connected with a connector 15 through a fixedly connected pin 14 and a pin hole 7-4, the left end of the right half shaft 7-5 is mounted on a left half shaft whole body 7-1 through a closed cover 7-3 and a left half shaft hole 7-8, the left half shaft whole body 7-1 can rotate with the right half shaft 7-5, a torsion spring 7-2 is sleeved on the right half shaft 7-5, the left end of the torsion spring 7-2 is fixedly connected in a torsion spring fixing hole 7-7 of the left half shaft, and a thrust bolt 7-6 fixedly connected on the right half shaft 7-5 pushes the right end of the torsion spring 7-2 to twist the torsion spring 7-2 through mutual rotation of the two half shafts to load.

Further, the single chip microcomputer 12 is used for detecting the motor index position, controlling the motor movement speed, changing the motor movement direction and communicating with the MAT L AB and the second single chip microcomputer 13, and the second single chip microcomputer 13 is used for reading the encoder signal, calculating the current encoder operation speed, comparing the encoder signal with the motor control signal to judge whether the motor loses steps and communicating with the MAT L AB and the first single chip microcomputer.

The embodiment of the invention provides a device for testing the torque characteristics of a stepping motor, which has the core improvement point of a mechanism for loading, measuring and testing the torque.

As shown in FIG. 1, the stepping motor and the torsion testing device based on the torsion spring are both arranged on the bottom plate through a bracket.

The stepping motor is connected to a rear testing device through a coupler. The coupling is a diaphragm spring coupling to adapt to form and position errors in a certain range.

The torsion testing device based on the torsion spring is shown in fig. 2, the left end of the torsion spring is fixedly installed on a left shaft connected with the motor through a torsion spring fixing hole in the shell, the right end of the torsion spring interferes with a bolt installed on a right shaft, and the bolt can limit the movement of the torsion spring.

When the stepping motor rotates at a certain speed, the torsion spring connected to the same shaft is driven to rotate. And the right shaft is at rest at this time. Because of the effect of bolt, the torsional spring takes place deformation, produces moment. The current torque can be calculated according to the deformation of the torsion spring.

The torque calculation needs to be carried out through the angular movement position information recorded by the encoder under the condition of no step loss.

A two-dimensional engineering drawing of the torsion spring based torque testing device is shown in fig. 5.

The logic block diagram of the control system of the invention is shown in fig. 6. The signal transfer and control logic relationship can be seen from this figure. The A, B signal line of encoder transmits the position of encoder to No. two singlechip, and I signal line passes through the index position of encoder to No. one singlechip.

The two singlechips are used in the invention, and the reason is mainly that the speed control of the stepping motor is accurate. The signal of the detection encoder needs to be interrupted, if a single chip microcomputer is used, the control pulse of the motor can be influenced, confusion is caused, and the speed control of the stepping motor is inaccurate.

The automatic test is started by clicking a running button in the MAT L AB program, a control flow chart in the MAT L AB is shown in FIG. 7, after the initial setting is completed, the MAT L AB sends a starting instruction to the second single chip microcomputer to enable the first single chip microcomputer to start to use a corresponding test program, and in the application process, the MAT L AB mainly works to read serial port data from the second single chip microcomputer.

The data mainly comprises the rotation speed of the encoder and the position of the encoder when the stepping motor loses steps, which is detected by the second singlechip.

Because the encoder and the stepping motor are fixed on the same shaft, the rotation speed of the encoder is the rotation speed of the stepping motor.

In addition, according to the position information of the encoder during the step loss, the torque of the torsion spring during the step loss, namely the maximum torque of the stepping motor at a certain rotating speed, can be obtained through calculation.

When MAT L AB reads the end signal that No. two singlechips sent, MAT L AB will automatic stop the test to close the drawing window, save the result in excel automatically.

Different stepper motor drive patterns, i.e., full step, half step, and sub-divided drive patterns, may be provided in the MAT L AB.

After the single chip microcomputer of the stepping motor receives the signal, the step length of the stepping motor can be controlled, and corresponding test can be carried out.

A test cycle movement of the stepper motor is illustrated in fig. 8. Before loading, the torque loading and measuring mechanism 7 is in a zero-load state under the action of the torsion spring 7-2, and after the main control computer sends an operation starting instruction, the first singlechip 12 controls the stepping motor 2 to be tested to drive the left half shaft whole 7-1 and the encoder code disc arranged on the left half shaft whole to rotate reversely to search the index position of the hollow encoder 5, when the index position is reached, the stepping motor 2 to be tested accelerates the forward running to the zero load position to reach the target speed, then the torque loading and measuring mechanism 7 is loaded by keeping the target speed rotating, when the second singlechip 13 detects that the output position of the hollow encoder 5 is asynchronous with the stepping motor 2 to be measured, namely, the motor 2 loses steps, the second singlechip 13 sends the step losing position and the speed of the motor 2 to a main control computer, and simultaneously, a signal is sent to the single chip microcomputer 12 to control the motor 2 to return to the index position and change the speed to start the next test cycle.

According to the test cycle of the stepping motor, the control logic of the single chip microcomputer in charge of controlling the stepping motor is shown in fig. 9, after the initialization setting is completed, the speed parameter setting is firstly carried out according to the step length signal sent by MAT L AB, and the single chip microcomputer can control the movement direction and the movement speed of the motor and simultaneously receive the index position signal from the I port of the encoder.

The single chip microcomputer listens to signals from the encoder through the interrupt program, and when the encoder reaches an index position, the single chip microcomputer sets an index position signal. After the first single chip microcomputer recognizes, the movement direction of the stepping motor can be changed. The position signal of the encoder is reset by the second singlechip on software by sending a signal to the second singlechip.

In addition, the single chip microcomputer listens to a step loss signal from the second single chip microcomputer through another interrupt program. After hearing the step loss signal, a signal instruction for changing the direction of the motor is set in the single chip microcomputer, so that the main program controls the stepping motor to rotate.

If the stepping motor has not lost steps, the first single chip microcomputer is used for controlling the speed of the stepping motor. In each cycle, the stepping motor has a target speed, and in order to measure the maximum torque at the target speed, the stepping motor keeps constant speed after reaching the target speed through acceleration until the torsion spring reaches the maximum torque.

The control logic of the second single chip microcomputer is shown in fig. 10, and after initialization setting is completed, speed parameter setting is performed according to a step signal sent by the MAT L AB.

When a test starting signal sent by MAT L AB is detected, the second singlechip informs the first singlechip to start testing.

The second single chip microcomputer mainly has the functions of reading pulse signals of the encoder and acquiring the position of the encoder in real time.

When the number of pulses is sufficient, the speed of the encoder can be calculated.

When the output pulse signal of the encoder detected by the second single chip microcomputer is consistent with the input control signal of the first single chip microcomputer, the stepping single chip microcomputer operates normally, and when the two signals are inconsistent, it can be judged that the stepping motor loses steps. Wherein, the stepping motor control signal of the singlechip I is transmitted to the singlechip II through interruption.

When the second single chip microcomputer detects that the stepping motor loses steps, a cycle end signal is informed to the second single chip microcomputer, and the motor speed and the motor position are sent to the MAT L AB through serial port communication.

When the output pulse signal of the encoder is detected to be zero, the motor is judged to be locked, and then the single chip microcomputer and the MAT L AB are informed to terminate the test.

While the foregoing description shows and describes the preferred embodiments of the present invention, it is to be understood that the invention is not limited to the forms disclosed herein, but is not to be construed as excluding other embodiments and is capable of use in various other combinations, modifications, and environments and is capable of changes within the scope of the inventive concept as described herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. An economical and practical automatic testing device for the torque pulling characteristic of a stepping motor is characterized by comprising a mechanical device and a control system, wherein the mechanical device comprises a stepping motor (2) to be tested, the stepping motor (2) to be tested is fixedly connected with a motor support (3) through a bolt, the motor support (3) is fixedly installed on a bottom plate (1), an output shaft of the stepping motor (2) to be tested is fixedly connected with one end of a coupler (4), the other end of the coupler (4) is fixedly connected with a torque loading and measuring mechanism (7), a hollow encoder (5) is fixedly installed on a left half shaft of the torque loading and measuring mechanism (7), a detection part of the hollow encoder (5) is fixedly installed on the bottom plate (1) through an encoder support (6), a left half shaft and a right half shaft of the torque loading and measuring mechanism (7) are respectively installed on a left support (8) and a right support (9) through a bearing (10) and a connector (15) through the half shaft, the left main control support (8) and the right support (9) are respectively fixedly connected with a left end of a torsion spring (7) through a torsion pin (7-7) and a left end of a single chip microcomputer (7) and a right end (7) through a torsion control pin (7-7) and a single chip microcomputer control pin (7), the single chip microcomputer control system is connected with a single chip microcomputer (7) through a single chip microcomputer (7-7) and a single chip microcomputer (7) and a single chip microcomputer control pin (7) for controlling the single chip microcomputer control system, the single chip microcomputer control system is connected with a single chip microcomputer control system for controlling the single chip microcomputer (7-7) through a single chip microcomputer (7) for controlling the single chip microcomputer (7).

2. The economical and practical automatic testing device for the pulling torque characteristics of the stepping motor as claimed in claim 1, wherein the MAT L AB control system is used for starting the whole automatic testing system by sending control signals to the two singlechips, reading speed and position signals of the encoder from the singlechips of the encoder, calculating torsion spring torque according to the position of the encoder, and automatically storing motion data and drawing a torque characteristic curve of the stepping motor when each test is finished.