Automatic rotational inertia measuring device and measuring method

Abstract

The invention discloses an automatic rotational inertia measuring device and method. The automatic rotational inertia measuring device comprises a shell; the motor is arranged in the shell; the rotary table penetrates through the top surface of the shell and is connected to the motor, and a photoelectric timing mechanism is arranged between the rotary table and the shell; and the control panel is arranged on the shell and is used for controlling the motor to work. The measuring method comprises the following steps of: initializing the main chip and the auxiliary chip, initializing the main display and the auxiliary display, operating buttons, automatically measuring, automatically calculating and displaying a result. The structure of the measuring device can be simplified, the manufacturing cost of the measuring device can be greatly reduced, meanwhile, the labor intensity of manual operation is reduced, measured data can be visually presented conveniently, and use is flexible and convenient.

Description

Technical Field

[0001] The present invention relates to an automated moment of inertia measuring device and a measuring method. Background Art

[0002] The moment of inertia is a fundamental quantity in structural dynamics and kinematic calculations and is widely used in various engineering fields related to mechanics. The moment of inertia is a physical quantity that describes the inertia of a rigid body rotating about an axis and is an essential piece of data for rotating components in industry. Currently, there are mainly two ways to obtain the moment of inertia: 1. Theoretical calculation, which is applicable to simple and regular structures and can directly calculate using the theoretical methods and formulas for the moment of inertia in theoretical mechanics; 2. Experimental measurement, which can target complex structures for experimental measurement to obtain the moment of inertia of the structure. When the object is irregular and cannot be calculated, only experimental methods can be used for measurement.

[0003] Currently, moment of inertia instruments mainly focus on: the free-fall method, the torsion pendulum method, the string pendulum method, and some instruments with potential energy storage to create a constant torque or an equivalent torque, or indirectly calculate and measure using the parallel axis theorem. Such methods have a high demand for manual operation, increasing the labor intensity of manual operation, and the cost of the instruments is relatively high. Summary of the Invention

[0004] The purpose of the present invention is to provide a technical solution for an automated moment of inertia measuring device and a measuring method aiming at the deficiencies of the existing technology. It can not only simplify the structure of the measuring device, but also greatly reduce the manufacturing cost of the measuring device. At the same time, it reduces the labor intensity of manual operation, facilitates the intuitive presentation of measurement data, is flexible and convenient to use. The measuring method has simple steps, effectively solves the problems of the high cost of moment of inertia measurement and the non-intuitive demonstration of the relationship between the moment of inertia and torque in physics teaching, and proposes a more concise operation method, which is beneficial to the more intuitive presentation of data.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions:

[0006] An automated moment of inertia measuring device, characterized in that it includes

[0007] A housing;

[0008] A motor, which is arranged inside the housing;

[0009] A turntable, which penetrates the top surface of the housing and is connected to the motor. There is an optoelectronic timing mechanism between the turntable and the housing;

[0010] And a control panel, which is arranged on the housing and used to control the operation of the motor.

[0011] Through the design of the above structure, not only can the structure of the measuring device be simplified, but also the manufacturing cost of the measuring device can be greatly reduced. At the same time, the labor intensity of manual operation can be reduced, which is convenient for the intuitive presentation of measurement data and flexible and convenient to use.

[0012] Further, the optoelectronic timing mechanism includes a grating, a photoelectric gate and a photoelectric sensor. The grating is arranged at the bottom of the turntable and is used to rotate synchronously with the turntable. The photoelectric gate is arranged in the outer shell, and the photoelectric sensor is embedded in the photoelectric gate. When the grating rotates along the photoelectric gate, the signal is detected by the photoelectric sensor and high and low levels are output. When the photoelectric gate is blocked by light, a high level can be output, and when it is transparent, a low level can be output. The widths of the light-blocking slices and the light-transmitting holes on the grating are equal, so that the time is recorded each time the level changes, and the recorded time is the time when the turntable rotates through a certain angle.

[0013] Further, a circuit board is arranged in the control panel. The circuit board is provided with a main chip, a sub-chip, an analog-to-digital conversion chip, a Hall current sensor, a constant current source module and a main-sub chip communication structure. The main chip communicates with the sub-chip through the main-sub chip communication structure. The main chip is electrically connected to the photoelectric sensor and the constant current source module. The sub-chip is connected to the Hall current sensor through the analog-to-digital conversion chip. The Hall current sensor is electrically connected to the constant current source module. The main-sub chip communication structure adopts eight one-way information transmission channels of NOT gate structures. Through the design of the above structure, when the level active change end is at a high level, the level passive change end is also at a high level, and when the level active change end is at a low level, the level passive change end is also at a low level, so as to realize signal transmission and data transmission.

[0014] Further, both the main chip and the sub-chip adopt STC89C52 single-chip microcomputers.

[0015] Further, a main display, a sub-display, buttons and knobs are arranged on the outer side of the control panel. The main display, the buttons and the knobs are electrically connected to the main chip, and the sub-display is electrically connected to the sub-chip.

[0016] Further, a charging port and a switch are arranged on the outer shell. The charging port and the switch are electrically connected to the control panel and the motor. Support blocks are arranged at the bottom of the outer shell for the horizontal placement of the measuring device.

[0017] For the measuring method of the automatic moment of inertia measuring device as described above, it is characterized by including the following steps:

[0018] S1. Initialization settings of the main chip and the sub-chip

[0019] a. Set all the P1 pins of the main chip and the sub-chip to a high level, set the P3.2 pin of the main chip to a high level, set the P3.3 pin to a low level, turn off the motor circuit, and turn on the resistor circuit;

[0020] b. Initialize the constant current source module that is manipulated by the 8-bit of the P2 pin of the main chip. Adjust the output current of the constant current source module by changing the resistance to output an analog signal through the button and the knob.

[0021] c. Set the P3.0, P3.1, and P3.6 pins of the main chip to high level, and set the pins connected to the button, the knob, and the photoelectric sensor to the receiving state.

[0022] S2. Initial settings for the main display and the secondary display

[0023] Initialize the content of the main display by the main chip and initialize the content of the secondary display by the secondary chip.

[0024] S3. Button operations

[0025] a. When the left button among the button and the knob is pressed, the P3.0 pin of the main chip changes from high level to low level. When the left button is released, the P3.0 pin of the main chip changes from low level to high level. A change signal is obtained inside the chip, and corresponding next-step responses are made.

[0026] b. When the right button among the button and the knob is pressed, the P3.1 pin of the main chip changes from high level to low level. When the right button is released, the P3.1 pin of the main chip changes from low level to high level. A change signal is obtained inside the chip, and corresponding next-step responses are made.

[0027] S4. Automatic measurement

[0028] a. On the initial interface, when the left button among the button and the knob is pressed, it is a zero-adjustment process. When the right button among the button and the knob is pressed, it is a formal test process.

[0029] b. The main chip locks the output current magnitude. The secondary chip receives the information transmitted back by the analog-to-digital conversion chip. The main chip and the secondary chip start to receive the information transmitted back by the photoelectric timing mechanism. The main chip shuts off the resistance circuit, turns on the motor circuit, and performs real-time information transmission with the secondary chip.

[0030] c. The P3.2 pin of the secondary chip is set to low level, the P3.0 pin is set to low level, the P3.3 pin is set to low level, the P3.3 pin is set to high level, the P3.0 pin is set to high level, the P3.3 pin is set to low level, the P3.0 pin is set to low level, completing the data conversion and acquisition process of the analog-to-digital conversion chip. After the acquisition is completed, the EOC pin of the analog-to-digital conversion chip is set to high level, driving the P3.1 pin of the secondary chip to be set to high level and the P3.2 pin of the secondary chip to be set to high level. At this time, the eight-bit binary number of the P0 pin of the secondary chip is received to obtain the current value, and this current value is stored in the cache. The P3.2 pin of the secondary chip is set to low level, completing the acquisition of the current magnitude analog-to-digital conversion.

[0031] d. The Hall current sensor collects the magnitude of the current in the motor circuit or the resistance circuit, linearly outputs an analog signal to its own Vout pin, and is received by the IN-0 pin of the analog-to-digital conversion chip to complete the collection;

[0032] e. When starting the measurement, the P3.2 pin of the main chip is set to low level, and the P3.3 pin of the main chip is set to high level. The current circuit is switched to the motor. At the same time, the Hall current sensor and the analog-to-digital conversion chip operate together. The motor starts to rotate with a constant current, outputs a constant torque, drives the turntable to start rotating, and causes an interaction between the grating and the photoelectric gate;

[0033] A low-level pulse is sent from the P1.0 pin of the main chip to the P1.0 pin of the secondary chip. When the P1.2 pin of the secondary chip is set to low level, it drives the P1.2 pin of the main chip to be set to low level, indicating that the synchronization is successful, and the secondary chip synchronously enters the data collection mode;

[0034] Data collection starts when the grating rotates. When blocking light, the LIGHT_GATE pin of the photoelectric gate is set to low level, which makes the P1.0 pin of the main chip set to low level, and then drives the P1.0 pin of the secondary chip to be set to low level; when transmitting light, the LIGHT_GATE pin of the photoelectric gate is set to high level, which makes the P1.0 pin of the main chip set to high level, and then drives the P1.0 pin of the secondary chip to be set to high level;

[0035] Whenever the level of the P3.6 pin of the main chip changes, the internal counter of the main chip adds the time value between two level changes of the counter to an array;

[0036] Whenever the level of the P1.0 pin of the secondary chip changes, the magnitude of the current collected by the current analog-to-digital conversion chip at present is added to an array. The data in the two arrays correspond one by one. After the time data in the main chip and the current magnitude data in the secondary chip are collected, the P1.2 pin of the secondary chip drives the level of the P1.2 pin of the main chip back to high level;

[0037] S5. Automatic calculation and result presentation

[0038] a. After the measurement is completed, press the right button among the button and the knob to select to start the calculation;

[0039] b. The main chip receives the current data from the secondary chip through the information transmission module and calculates the measurement result of the moment of inertia: If it is the zero adjustment process, the result is defined as J0 and stored in the cache; if it is the formal measurement process, the result minus J0 is defined as J and stored in the cache;

[0040] c. The level information received by the P1.2 pin of the main chip returns to high level, and the secondary chip enters the waiting state. When the P1.1 pin of the main chip goes to low level, and at the next moment, the P1.0 pin goes to low level and the P1.1 pin goes to high level, the two chips synchronously enter the data transmission mode. Each four-digit current data in the current array is split into four-bit binary numbers one by one. By changing the levels of the P1.4 to P1.7 pins of the secondary chip, the levels of the P1.4 to P1.7 pins of the main chip are driven to be transmitted successively. During the transmission process, each data has four digits that need to be transmitted separately once. The changes of the P1.2 and P1.3 pins of the secondary chip are used to indicate the completion of assignment. After the levels of the P1.4 to P1.7 pins of the secondary chip change for the first time and become stable, the levels of the P1.2 and P1.3 pins of the secondary chip are set from high level to low level. The main chip receives the data, changes the level of the P1.1 pin of the main chip, and the secondary chip receives it and performs the next data transmission, so as to synchronously and cyclically receive data;

[0041] d. When all the data in the array is transmitted, that is, when the main chip finishes receiving the data, the level of the P1.0 pin of the main chip is reset to high level, and the data transmission is completed. The time array and the current magnitude array are stored in the main chip;

[0042] e. Through the code, operations are performed using the formula, and the zeroing value is assigned or the result is presented, and the measurement is completed.

[0043] This measurement method has simple steps. It not only effectively solves the problems of high cost in measuring the moment of inertia and the non-intuitive demonstration of the relationship between the moment of inertia and torque in physics teaching, but also proposes a more concise operation method, which is conducive to presenting data more intuitively.

[0044] Furthermore, when the main chip initializes the content of the main display in step S2, it specifically includes the following steps:

[0045] a. Set the P3.5 pin of the main chip to low level, set the P0.0 pin to high level, set the other pins of P0 to low level, set the P3.4 pin to high level, and after a delay of 5 ms, set it to low level to clear the screen;

[0046] b. Set the P0.7 pin of the main chip to high level, set the other pins of P0 to low level, set the P3.4 pin to high level, and after a delay of 5 ms, set it to low level to define the cursor at the beginning of the first line;

[0047] c. Set the P3.5 pin of the main chip to high level, start writing the data of the first line, define the level information of the eight pins of P0 with the ASCII code of the character, that is, an eight-bit binary number, set the P3.4 pin to high level, and after a delay of 5 ms, set it to low level. One character is successfully displayed, the cursor automatically moves one position backward, and the next character is defined;

[0048] d. Define the pointer position for inserting characters in the second line. Set the P3.5 pin of the main chip to low level, then set the P0.6 and P0.7 pins to high level, set the other pins of P0 to low level, set the P3.4 pin to high level, set it to low level after a 5 ms delay, and define the cursor at the beginning of the second line;

[0049] e. Set the P3.5 pin of the main chip to high level and start writing the data for the second line. Define the level information of the eight pins of P0 with the ASCII code of the character, that is, an eight-bit binary number. Set the P3.4 pin to high level, set it to low level after a 5 ms delay, successfully display one character, automatically move the cursor one position backward, and define the next character.

[0050] Furthermore, when the secondary chip initializes the content of the secondary display in step S2, it specifically includes the following steps:

[0051] a. Set the P3.5 pin of the secondary chip to low level, set the P2.0 pin to high level, set the other pins of P2 to low level, set the P3.4 pin to high level, set it to low level after a 5 ms delay, and clear the screen;

[0052] b. Set the P2.7 pin of the secondary chip to high level, set the other pins of P2 to low level, set the P3.4 pin to high level, set it to low level after a 5 ms delay, and define the cursor at the beginning of the first line;

[0053] c. Set the P3.5 pin of the secondary chip to high level and start writing the data for the first line. Define the level information of the eight pins of P2 with the ASCII code of the character, that is, an eight-bit binary number. Set the P3.4 pin to high level, set it to low level after a 5 ms delay, successfully display one character, automatically move the cursor one position backward, and define the next character;

[0054] d. Define the pointer position for inserting characters in the second line. Set the P3.5 pin to low level, then set the P2.6 and P2.7 pins to high level, set the other pins of P2 to low level, set the P3.4 pin to high level, set it to low level after a 5 ms delay, and define the cursor at the beginning of the second line;

[0055] e. Set the P3.5 pin to high level and start writing the data for the second line. Define the level information of the eight pins of P2 with the ASCII code of the character, that is, an eight-bit binary number. Set the P3.4 pin to high level, set it to low level after a 5 ms delay, successfully display one character, automatically move the cursor one position backward, and define the next character.

[0056] Furthermore, after the time data in the main chip and the current magnitude data in the secondary chip in process e of step S4 are collected, they are transmitted to the main chip for joint calculation. The main chip and the secondary chip achieve the common change of levels through eight one-way information transmission channels with NOT gate structures.

[0057] Due to the adoption of the above technical solution, the present invention has the following beneficial effects:

[0058] 1. The present invention can not only simplify the structure of the measuring device, but also greatly reduce the manufacturing cost of the measuring device. At the same time, it reduces the labor intensity of manual operation, facilitates the intuitive presentation of measurement data, and is flexible and convenient to use.

[0059] 2. The measurement method of the present invention has simple steps. It not only effectively solves the problems of high cost in measuring the moment of inertia and the non-intuitive demonstration of the relationship between the moment of inertia and torque in physics teaching, but also proposes a more concise operation method, which is conducive to presenting data more intuitively. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The present invention will be further described below with reference to the drawings:

[0061] Figure 1 is a schematic structural diagram of the measuring device in the automatic moment of inertia measuring device and measuring method of the present invention;

[0062] Figure 2 is Figure 1 a schematic structural diagram of the rear side;

[0063] Figure 3 is a schematic internal structure diagram of the present invention;

[0064] Figure 4 is a schematic connection diagram of the grating and the turntable in the present invention;

[0065] Figure 5 is a schematic structural diagram of the photoelectric timing mechanism in the present invention;

[0066] Figure 6 is a circuit block diagram of the present invention;

[0067] Figure 7 is a circuit diagram of the main chip in the present invention;

[0068] Figure 8 is a circuit diagram of the sub-chip in the present invention;

[0069] Figure 9 is a flow chart of the measurement method in the present invention;

[0070] Figure 10 is a relationship diagram between the motor output torque and the armature in the present invention.

[0071] In the figure: 1 - turntable; 2 - housing; 3 - control panel; 4 - support block; 5 - motor; 6 - photoelectric door; 7 - photoelectric sensor; 8 - grating; 9 - charging port; 10 - switch. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0072] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0073] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0074] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion.

[0075] As Figures 1 to 8 shown, the automatic moment of inertia measuring device of the present invention includes a housing 2, a motor 5, a turntable 1 and a control panel 3. The motor 5 is arranged inside the housing 2.

[0076] The turntable 1 penetrates through the top surface of the housing 2 and is connected to the motor 5. An optoelectronic timing mechanism is provided between the turntable 1 and the housing 2.

[0077] The optoelectronic timing mechanism includes a grating 8, a photoelectric gate 6 and a photoelectric sensor 7. The grating 8 is arranged at the bottom of the turntable 1 and is used to rotate synchronously with the turntable 1. The photoelectric gate 6 is arranged inside the housing 2. The photoelectric sensor 7 is embedded in the photoelectric gate 6. When the grating 8 rotates along the photoelectric gate 6, the signal is detected by the photoelectric sensor 7 and high and low levels are output. When the photoelectric gate 6 is blocked by light, a high level can be output. When it is transparent, a low level can be output. The widths of the light-blocking pieces and the light-transmitting holes on the grating 8 are equal, so that the time is recorded each time the level changes, and the recorded time is the time when the turntable 1 rotates through a certain angle.

[0078] The control panel 3 is arranged on the housing 2 and is used to control the operation of the motor 5.

[0079] The control panel 3 is provided with a circuit board, which is provided with a main chip, a secondary chip, an analog-to-digital conversion chip, a Hall current sensor, a constant current source module, and a main-secondary chip communication structure. The main chip communicates with the secondary chip through the main-secondary chip communication structure. The main chip is electrically connected to the photoelectric sensor 7 and the constant current source module. The secondary chip is connected to the Hall current sensor through the analog-to-digital conversion chip. The Hall current sensor is electrically connected to the constant current source module. The main-secondary chip communication structure adopts eight unidirectional information transmission channels of NOT gate structures. Through the design of the above structure, when the active level change end is at a high level, the passive level change end is also at a high level; when the active level change end is at a low level, the passive level change end is also at a low level, realizing signal transmission and data transmission.

[0080] Both the main chip and the secondary chip adopt STC89C52 single-chip microcomputers. The analog-to-digital conversion chip adopts ADC0809. The Hall current sensor adopts WCS2702.

[0081] On the outside of the control panel 3, there are a main display, a secondary display, buttons, and a knob. The main display, buttons, and knob are electrically connected to the main chip, and the secondary display is electrically connected to the secondary chip. Both the main display and the secondary display adopt LCD1602.

[0082] The housing 2 is provided with a charging port 9 and a switch 10. The charging port 9 and the switch 10 are electrically connected to the control panel 3 and the motor 5. The bottom of the housing 2 is provided with a support block 4 for measuring the horizontal placement of the device.

[0083] Through the design of the above structure, not only can the structure of the measuring device be simplified, but also the manufacturing cost of the measuring device can be greatly reduced. At the same time, the labor intensity of manual operation is reduced, facilitating the intuitive presentation of measurement data, and making it flexible and convenient to use.

[0084] The physical detection effect generated by the measuring device is determined by the motor, the turntable with a grating, and the photoelectric sensor.

[0085] The motor adopts a motor with a constant torque constant, which can be given by the motor manufacturer. The torque constant is the ratio of the output torque of the motor to the magnitude of the current passing through the motor, and is determined by the motor structure and material properties. This value is independent of the magnitude of the current and is only related to the degree of aging and rotation state of the motor.

[0086] Taking the grating's light-transmitting hole angle of 3.6°, its light-blocking sheet angle of 3.6°, and the distance from the rotation center r = 50 mm as an example, the widths of the light-transmitting hole and the light-blocking sheet are calculated.

[0087] The photoelectric sensor of the photoelectric gate outputs two different levels in the light-blocking state and the light-transmitting state. Since the widths of the light-transmitting hole and the light-blocking sheet are the same, the time interval between two consecutive level changes is the time it takes for the turntable to rotate 3.6°.

[0088] When the measuring device measures the physical quantity of the moment of inertia:

[0089] I. Original physical quantities:

[0090] 1. Influence of motor torque constant and motor friction on motor output torque:

[0091] Motor torque constant: Kt (N*cm / mA).

[0092] Motor friction: For rolling bearings at low speeds: Frictional torque T = T0 + k*ω, where ω represents the angular velocity of the motor rotation, and the unit of T is N*cm.

[0093] Other frictions are a fixed value represented by T1, so T = T0 + k*ω + T1.

[0094] The measuring device does not make a technological innovation to the motors used, and existing motors can be adopted, but their parameters can be selected according to actual usage requirements.

[0095] 2. Change time interval of the level: Δt (ms)

[0096] 3. Change time interval of the level last time: Δt0 (ms)

[0097] 4. Magnitude of the current passing through the motor: I (mA)

[0098] 5. Angle rotated by the turntable during a single level change: Δθ = 3.6°

[0099] II. Derived physical quantities:

[0100] 1. Angular velocity ω of the turntable

[0101]

[0102] 2. Acceleration a of the turntable

[0103]

[0104] 3. Motor output torque M

[0105] M = Kt*I - T = J*a.

[0106] 4. Moment of inertia (moment of inertia between two certain level changes)

[0107]

[0108] During the grating timing process, when the turntable starts to rotate, the time from the first level change to the second level change is recorded as t0, and the time from the second level change to the third level change is recorded as t1. Also, the magnitude of the current value between the second level change and the third level change is taken, and the angular velocity is the angular velocity from the second level change to the third level change. That is, when the grating starts to rotate and after the second level change, the first calculation begins, and the time before the first level change is left vacant to prevent differences caused by different starting angles of the motor. Since this time cannot be used as data, another data collection is performed, that is, t0 between the first level change and the second level change, which is used as the previous data for the first data calculation. Then t1 between the second level change and the third level change is obtained, and so on. Through recursive calculation and expansion of the operation, after 400 calculations, the average value is taken to obtain the final value.

[0109] Use the same subscript in the array to represent the same time:

[0110] Level change time intervals [t0, t1, …, t 400

[0111] Current magnitudes between level changes [I1, …, I 400

[0112] Angular velocity magnitudes between level changes

[0113] Substitute these into the formula

[0114]

[0115] to obtain [J1, …, J 400

[0116] Finally, take the average value to obtain the magnitude of the final moment of inertia J.

[0117] As Figure 9 shown, the measurement method of the automatic moment of inertia measuring device of the present invention includes the following steps:

[0118] S1. Initialize the main chip and the sub - chip

[0119] a. Set all the P1 pins of the main chip and the sub - chip to high level, set the P3.2 pin of the main chip to high level, set the P3.3 pin to low level, turn off the motor 5 circuit, and turn on the resistor circuit;

[0120] b. Initialize the constant - current source module controlled by the 8 - bit P2 pin of the main chip, and adjust the magnitude of the output current of the constant - current source module by changing the resistance output analog signal through the button and the knob;

[0121] ​​​c. Set the pins P3.0, P3.1, and P3.6 of the main chip to high level, and set the connection pins of the button, knob, and photoelectric sensor 7 to the receiving state;

[0122] S2. Initialization settings for the main display and secondary display

[0123] Initialize the content of the main display by the main chip and initialize the content of the secondary display by the secondary chip;

[0124] When the main chip initializes the content of the main display, it specifically includes the following steps:

[0125] a. Set the P3.5 pin of the main chip to low level, set the P0.0 pin to high level, set the other pins of P0 to low level, set the P3.4 pin to high level, set it to low level after a 5ms delay, and clear the screen;

[0126] b. Set the P0.7 pin of the main chip to high level, set the other pins of P0 to low level, set the P3.4 pin to high level, set it to low level after a 5ms delay, and define the cursor at the beginning of the first line;

[0127] c. Set the P3.5 pin of the main chip to high level, start writing the data of the first line, define the level information of the eight pins of P0 with the ASCII code of the character, that is, an eight-bit binary number, set the P3.4 pin to high level, set it to low level after a 5ms delay, successfully display a character, the cursor automatically moves one bit backward, and define the next character;

[0128] d. Define the pointer position for inserting characters in the second line, set the P3.5 pin of the main chip to low level, then set the P0.6 and P0.7 pins to high level, set the other pins of P0 to low level, set P3.4 to high level, set it to low level after a 5ms delay, and define the cursor at the beginning of the second line;

[0129] e. Set the P3.5 pin of the main chip to high level, start writing the data of the second line, define the level information of the eight pins of P0 with the ASCII code of the character, that is, an eight-bit binary number, set the P3.4 pin to high level, set it to low level after a 5ms delay, successfully display a character, the cursor automatically moves one bit backward, and define the next character.

[0130] When the secondary chip initializes the content of the secondary display, it specifically includes the following steps:

[0131] a. Set the P3.5 pin of the secondary chip to low level, set the P2.0 pin to high level, set the other pins of P2 to low level, set the P3.4 pin to high level, set it to low level after a 5ms delay, and clear the screen;

[0132] b. Set the P2.7 pin of the secondary chip to high level, set the other pins of P2 to low level, set the P3.4 pin to high level, set it to low level after a 5 ms delay, and define the cursor at the beginning of the first line;

[0133] c. Set the P3.5 pin of the secondary chip to high level, start writing the data of the first line, define the level information of the eight pins of P2 with the ASCII code of the character, that is, an eight-bit binary number, set the P3.4 pin to high level, set it to low level after a 5 ms delay, successfully display a character, the cursor automatically moves one position backward, and define the next character;

[0134] d. Define the pointer position for inserting characters in the second line, set the P3.5 pin to low level, then set the P2.6 and P2.7 pins to high level, set the other pins of P2 to low level, set the P3.4 pin to high level, set it to low level after a 5 ms delay, and define the cursor at the beginning of the second line;

[0135] e. Set the P3.5 pin to high level, start writing the data of the second line, define the level information of the eight pins of P2 with the ASCII code of the character, that is, an eight-bit binary number, set the P3.4 pin to high level, set it to low level after a 5 ms delay, successfully display a character, the cursor automatically moves one position backward, and define the next character.

[0136] S3. Button operation

[0137] a. When the left button in the button and the knob is pressed, the P3.0 pin of the main chip changes from high level to low level. When the left button is released, the P3.0 pin of the main chip changes from low level to high level. The chip internal gets the change signal and makes the corresponding next response;

[0138] b. When the right button in the button and the knob is pressed, the P3.1 pin of the main chip changes from high level to low level. When the right button is released, the P3.1 pin of the main chip changes from low level to high level. The chip internal gets the change signal and makes the corresponding next response;

[0139] S4. Automatic measurement

[0140] a. In the initial interface, when the left button in the button and the knob is pressed, it is the zero adjustment process. When the right button in the button and the knob is pressed, it is the formal test process;

[0141] b. The main chip locks the current output size, the secondary chip receives the information transmitted back by the analog-to-digital conversion chip, the main chip and the secondary chip start to receive the information transmitted back by the optoelectronic timing mechanism, the main chip shuts off the resistance circuit, turns on the motor 5 circuit, and conducts real-time information transmission with the secondary chip; the main chip fixes the current size output by the artificially regulated constant current source module through the eight pins of P2;

[0142] c. Set the P3.2 pin of the slave chip to low level, the P3.0 pin to low level, the P3.3 pin to low level, the P3.3 pin to high level, the P3.0 pin to high level, the P3.3 pin to low level, and the P3.0 pin to low level to complete the data conversion and acquisition process of the analog-to-digital conversion chip. After the acquisition is completed, set the EOC pin of the analog-to-digital conversion chip to high level, which drives the P3.1 pin of the slave chip to high level and the P3.2 pin of the slave chip to high level. At this time, receive the eight-bit binary number of the P0 pin of the slave chip to obtain the current value, store the current value in the cache, and set the P3.2 pin of the slave chip to low level to complete the acquisition of the current magnitude analog-to-digital conversion;

[0143] d. The Hall current sensor collects the magnitude of the current in the motor 5 circuit or the resistance circuit, linearly outputs an analog signal to its own Vout pin, and is received by the IN-0 pin of the analog-to-digital conversion chip to complete the acquisition;

[0144] e. When starting the measurement, set the P3.2 pin of the master chip to low level and the P3.3 pin to high level, switch the current line to the motor 5. At the same time, the Hall current sensor and the analog-to-digital conversion chip operate together, and the motor 5 starts to rotate with a constant current, outputs a constant torque, drives the turntable 1 to start rotating, and causes an interaction between the grating 8 and the photoelectric gate 6;

[0145] Send a low-level pulse from the P1.0 pin of the master chip to the P1.0 pin of the slave chip. When the P1.2 pin of the slave chip is set to low level, which drives the P1.2 pin of the master chip to low level, it proves that the synchronization is successful, and the slave chip synchronously enters the data collection mode;

[0146] When the grating 8 starts to rotate for data acquisition, when the light is blocked, the LIGHT_GATE pin of the photoelectric gate 6 is set to low level, which makes the P1.0 pin of the master chip set to low level, and then drives the P1.0 pin of the slave chip to low level; when the light passes through, the LIGHT_GATE pin of the photoelectric gate 6 is set to high level, which makes the P1.0 pin of the master chip set to high level, and then drives the P1.0 pin of the slave chip to high level;

[0147] Whenever the level of the P3.6 pin of the master chip changes, the internal counter of the master chip adds the time value between two level changes of the counter to an array (time value);

[0148] Whenever the level of the P1.0 pin of the slave chip changes, add the current magnitude collected by the current analog-to-digital conversion chip to an array (current value). The data of the two arrays correspond one by one. After the time data in the master chip and the current magnitude data in the slave chip are collected, the P1.2 pin of the slave chip drives the level of the P1.2 pin of the master chip back to high level;

[0149] After the time data in the main chip and the current magnitude data in the secondary chip are collected, they are transmitted to the main chip for joint calculation. The main chip and the secondary chip achieve common voltage level changes through eight one-way information transmission channels with NOT gate structures.

[0150] Pins P1.0 and P1.1 of the main chip can drive the voltage levels of pins P1.0 and P1.1 of the secondary chip to change rapidly together, and pins P1.2 to P1.7 of the secondary chip can drive the voltage levels of pins P1.2 to P1.7 of the main chip to change rapidly together.

[0151] Taking the example of pin P1.0 of the main chip driving pin P1.0 of the secondary chip in one of the paths: In the initial state, all voltage levels are high. When the voltage level of pin P1.0 of the main chip is set to low, the signal passes through the NOT gate and the inverted voltage level becomes high. This high voltage level acts on the MOSFET on this path, causing it to conduct. The pin P1.0 of the secondary chip was originally in an open circuit state with a high voltage level. When the MOSFET conducts, it is connected to the ground, causing the voltage level of pin P1.0 of the secondary chip to become low. Thus, when the voltage level of pin P1.0 of the main chip is set to low, the voltage level of pin P1.0 of the secondary chip is set to low.

[0152] When the voltage level of pin P1.0 of the main chip returns to high, the signal passes through the NOT gate and the inverted voltage level becomes low. This low voltage level acts on the MOSFET on this path, causing it to turn off. The pin P1.0 of the secondary chip was originally in a conducting state with a low voltage level. When the MOSFET turns off, it is disconnected from the ground, causing the voltage level of pin P1.0 of the secondary chip to return to high. Thus, when the voltage level of pin P1.0 of the main chip is set to high, the voltage level of pin P1.0 of the secondary chip is set to high.

[0153] S5. Automatic calculation and result presentation

[0154] a. After the measurement is completed, press the right button among the buttons and knobs to select to start the calculation;

[0155] b. The main chip receives the current data from the secondary chip through the information transmission module and calculates the measurement result of the moment of inertia: If it is a zero adjustment process, the result is defined as J0 and stored in the buffer; if it is a formal measurement process, the result minus J0 is defined as J and stored in the buffer; when it is a zero adjustment process, the English words "Zero adjustment successful" are presented on the screen, and options are given with the left button for re-zero adjustment and the right button for starting the measurement; when it is a formal measurement process, the liquid crystal display process is called, and the data J (the moment of inertia result) is presented on the display screen;

[0156] c. The level information received by the P1.2 pin of the main chip returns to high level, and the secondary chip enters the waiting state. When the P1.1 pin of the main chip goes to low level, and at the next moment, the P1.0 pin goes to low level and the P1.1 pin goes to high level, the two chips synchronously enter the data transmission mode. Each four-digit current data in the current array is successively split into four-bit binary numbers. By changing the levels of the P1.4 to P1.7 pins of the secondary chip to drive the levels of the P1.4 to P1.7 pins of the main chip for successive transmission. During the transmission process, each data has four digits that need to be transmitted separately once. The changes of the P1.2 and P1.3 pins of the secondary chip are used to indicate the completion of assignment. After the levels of the P1.4 to P1.7 pins of the secondary chip change for the first time and stabilize, the levels of the P1.2 and P1.3 pins of the secondary chip are set from high level to low level. The main chip receives the data, changes the level of the P1.1 pin of the main chip, and the secondary chip receives it and proceeds to the next data transmission, thus synchronously receiving data in a loop;

[0157] d. When all the data in the array is transmitted, that is, when the main chip finishes receiving the data, the level of the P1.0 pin of the main chip is reset to high level, and the data transmission is completed. The time array and the current magnitude array are stored in the main chip;

[0158] e. Through the code, operations are performed using the formula, and the zeroing value is assigned or the result is presented, and the measurement is completed.

[0159] This measurement method has simple steps. It not only effectively solves the problems of high cost in measuring the moment of inertia and the non-intuitive demonstration of the relationship between the moment of inertia and torque in physics teaching, but also proposes a more concise operation method, which is beneficial to presenting data more intuitively.

[0160] The above are only specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on the present invention to achieve substantially the same technical effects are all covered by the protection scope of the present invention.

Claims

1. Automatic moment of inertia measuring device, characterized in that: Comprising a housing; a motor disposed within the housing; a turntable that penetrates the top surface of the housing and is connected to the motor, and an optoelectronic timing mechanism is provided between the turntable and the housing; and a control panel disposed on the housing for controlling the operation of the motor.

2. The automated moment of inertia measuring device according to claim 1, wherein: The optoelectronic timing mechanism includes a grating, a photoelectric gate, and a photoelectric sensor. The grating is disposed at the bottom of the turntable and is used to rotate synchronously with the turntable. The photoelectric gate is disposed within the housing, and the photoelectric sensor is embedded within the photoelectric gate. When the grating rotates along the photoelectric gate, signals are detected by the photoelectric sensor and high and low levels are output.

3. The automated moment of inertia measuring device according to claim 2, characterized in that: A circuit board is provided within the control panel. The circuit board is provided with a main chip, a sub-chip, an analog-to-digital conversion chip, a Hall current sensor, a constant current source module, and a main-sub chip communication structure. The main chip communicates with the sub-chip through the main-sub chip communication structure. The main chip is electrically connected to the photoelectric sensor and the constant current source module. The sub-chip is connected to the Hall current sensor through the analog-to-digital conversion chip. The Hall current sensor is electrically connected to the constant current source module. The main-sub chip communication structure employs eight unidirectional information transmission channels of a NOT gate structure.

4. The automated moment of inertia measuring device according to claim 3, wherein: Both the main chip and the sub-chip employ STC89C52 single-chip microcontrollers.

5. The automated moment of inertia measuring device according to claim 3, characterized in that: A main display, a sub-display, buttons, and a knob are provided on the outer side of the control panel. The main display, the buttons, and the knob are electrically connected to the main chip, and the sub-display is electrically connected to the sub-chip.

6. The automated moment of inertia measuring device according to claim 1, wherein: A charging port and a switch are provided on the housing. The charging port and the switch are electrically connected to the control panel and the motor. Support blocks are provided at the bottom of the housing for the horizontal placement of the measuring device.

7. The measuring method of the automated moment of inertia measuring device according to any one of claims 1 to 6, characterized in that Including the following steps: S1. Initialization settings for the main chip and the sub-chip a. Set all the P1 pins of the main chip and the sub-chip to high level, set the P3.2 pin of the main chip to high level, and set the P3.3 pin to low level to turn off the motor circuit and turn on the resistor circuit; b. Initialize the constant current source module controlled by the 8-bit P2 pin of the main chip, and adjust the magnitude of the current output by the constant current source module by changing the resistance output analog signal through the buttons and the knob; c. Set the P3.0, P3.1, and P3.6 pins of the main chip to high level, and set the connection pins of the buttons, the knob, and the photoelectric sensor to the receiving state; S2. Initialization settings for the main display and the sub-display Initialize the content of the main display by the main chip and initialize the content of the sub-display by the sub-chip; S3. Button operations a. When the left button among the buttons and the knob is pressed, the P3.0 pin of the main chip changes from high level to low level. When the left button is released, the P3.0 pin of the main chip changes from low level to high level, and a change signal is obtained inside the chip to make a corresponding next response; b. When the right button among the buttons and the knob is pressed, the P3.1 pin of the main chip changes from high level to low level. When the right button is released, the P3.1 pin of the main chip changes from low level to high level, and a change signal is obtained inside the chip to make a corresponding next response; S4. Automatic measurement a. Initial interface: When the left button among the button and the knob is pressed, it is the zero adjustment process; when the right button among the button and the knob is pressed, it is the formal test process. b. The main chip locks the magnitude of the current output. The secondary chip receives the information transmitted back by the analog-to-digital conversion chip. The main chip and the secondary chip start to receive the information transmitted back by the optoelectronic timing mechanism. The main chip shuts off the resistor circuit, turns on the motor circuit, and conducts real-time information transmission with the secondary chip. c. The P3.2 pin of the secondary chip is set to low level, the P3.0 pin is set to low level, the P3.3 pin is set to low level, the P3.3 pin is set to high level, the P3.0 pin is set to high level, the P3.3 pin is set to low level, the P3.0 pin is set to low level, completing the data conversion and acquisition process of the analog-to-digital conversion chip. After the acquisition is completed, the EOC pin of the analog-to-digital conversion chip is set to high level, driving the P3.1 pin of the secondary chip to be set to high level, and the P3.2 pin of the secondary chip to be set to high level. At this time, the eight-bit binary number of the P0 pin of the secondary chip is received to obtain the current value, and this current value is stored in the cache. The P3.2 pin of the secondary chip is set to low level, completing the acquisition of the magnitude analog-to-digital conversion of the current. d. The Hall current sensor collects the magnitude of the current in the motor loop or the resistor loop, linearly outputs an analog signal to its own Vout pin, and is received by the IN-0 pin of the analog-to-digital conversion chip to complete the acquisition. e. When starting the measurement, the P3.2 pin of the main chip is set to low level, and the P3.3 pin of the main chip is set to high level. The current circuit is switched to the motor. At the same time, the Hall current sensor and the analog-to-digital conversion chip operate together. The motor starts to rotate with a constant current, outputs a constant torque, drives the turntable to start rotating, and causes an interaction between the grating and the photoelectric gate. A low-level pulse is emitted from the P1.0 pin of the main chip to the P1.0 pin of the secondary chip. When the P1.2 pin of the secondary chip is set to low level, it drives the P1.2 pin of the main chip to be set to low level, causing the secondary chip to synchronously enter the data collection mode. When the grating starts to rotate for data acquisition, when it blocks light, the LIGHT_GATE pin of the photoelectric gate is set to low level, causing the P1.0 pin of the main chip to be set to low level, and then driving the P1.0 pin of the secondary chip to be set to low level; when it transmits light, the LIGHT_GATE pin of the photoelectric gate is set to high level, causing the P1.0 pin of the main chip to be set to high level, and then driving the P1.0 pin of the secondary chip to be set to high level. Whenever the level of the P3.6 pin of the main chip changes, the time value between two level changes of the main chip is added to an array. Whenever the level of the P1.0 pin of the secondary chip changes, the magnitude of the current collected by the current analog-to-digital conversion chip at present is added to an array. The data in the two arrays correspond one by one. After the time data in the main chip and the current magnitude data in the secondary chip are collected, the P1.2 pin of the secondary chip drives the level of the P1.2 pin of the main chip back to high level. S5. Automatic calculation and result presentation a. After the measurement is completed, press the right button among the button and the knob to select to start the calculation. b. The main chip receives current data from the secondary chip through the information transmission module and calculates the measurement result of the moment of inertia: If it is the zero adjustment process, the result is defined as J0 and stored in the cache; if it is the formal measurement process, the result minus J0 is defined as J and stored in the cache. c. The level information received by the P1.2 pin of the main chip returns to high level, and the secondary chip enters the waiting state. When the P1.1 pin of the main chip goes to low level, and at the next moment, the P1.0 pin goes to low level and the P1.1 pin goes to high level, the two chips synchronously enter the data transmission mode. Each four-digit current data in the current array is split into four-bit binary numbers one by one. By changing the levels of the P1.4 to P1.7 pins of the secondary chip, the levels of the P1.4 to P1.7 pins of the main chip are driven to be transmitted successively. During the transmission process, each data has four digits that need to be transmitted separately once. The change of the P1.2 and P1.3 pins of the secondary chip is used to indicate the completion of assignment. After the levels of the P1.4 to P1.7 pins of the secondary chip change for the first time and stabilize, the levels of the P1.2 and P1.3 pins of the secondary chip are set from high level to low level. The main chip receives the data, changes the level of the P1.1 pin of the main chip, and the secondary chip receives it and proceeds to the next data transmission. In this way, data is received synchronously in a loop. d. When all the data in the array is transmitted, that is, when the main chip finishes receiving data, the level of the P1.0 pin of the main chip is reset to high level, the data transmission is completed, and the time array and the current magnitude array are stored in the main chip. e. Through the code, calculations are performed using the formula, and the zero adjustment value is assigned or the result is presented, and the measurement is completed.

8. The measuring method of the automated moment of inertia measuring device according to claim 7, characterized in that: When the main chip in step S2 initializes the content of the main display, it specifically includes the following steps a. Set the P3.5 pin of the main chip to low level, set the P0.0 pin to high level, set the other pins of P0 to low level, set the P3.4 pin to high level, and after a delay of 5 ms, set it to low level to clear the screen. b. Set the P0.7 pin of the main chip to high level, set the other pins of P0 to low level, set the P3.4 pin to high level, and after a delay of 5 ms, set it to low level to define the cursor at the beginning of the first line. c. Set the P3.5 pin of the main chip to high level, start writing the data of the first line, define the ASCII code of the character, that is, the eight-bit binary number, as the level information of the eight pins of P0, set the P3.4 pin to high level, and after a delay of 5 ms, set it to low level. One character is successfully displayed, the cursor automatically moves one position backward, and the next character is defined. d. Define the pointer position for inserting characters in the second line. Set the P3.5 pin of the main chip to low level, then set the P0.6 and P0.7 pins to high level, set the other pins of P0 to low level, set P3.4 to high level, and after a delay of 5 ms, set it to low level to define the cursor at the beginning of the second line. e. Set the P3.5 pin of the main chip to high level, start writing the data of the second line, define the ASCII code of the character, that is, the eight-bit binary number, as the level information of the eight pins of P0, set the P3.4 pin to high level, and after a delay of 5 ms, set it to low level. One character is successfully displayed, the cursor automatically moves one position backward, and the next character is defined.

9. The measuring method of the automatic moment of inertia measuring device according to claim 7, characterized in that: When the sub-chip in step S2 initializes the content of the sub-display, it specifically includes the following steps: a. Set the P3.5 pin of the sub-chip to low level, set the P2.0 pin to high level, set the other pins of P2 to low level, set the P3.4 pin to high level, set it to low level after a 5 ms delay, and clear the screen; b. Set the P2.7 pin of the sub-chip to high level, set the other pins of P2 to low level, set the P3.4 pin to high level, set it to low level after a 5 ms delay, and define the cursor at the beginning of the first line; c. Set the P3.5 pin of the sub-chip to high level, start writing the data of the first line, define the level information of the eight pins of P2 with the ASCII code of the character, that is, an eight-bit binary number, set the P3.4 pin to high level, set it to low level after a 5 ms delay, successfully display a character, the cursor automatically moves one position backward, and define the next character; d. Define the pointer position for inserting characters in the second line, set the P3.5 pin to low level, then set the P2.6 and P2.7 pins to high level, set the other pins of P2 to low level, set the P3.4 pin to high level, set it to low level after a 5 ms delay, and define the cursor at the beginning of the second line; e. Set the P3.5 pin to high level, start writing the data of the second line, define the level information of the eight pins of P2 with the ASCII code of the character, that is, an eight-bit binary number, set the P3.4 pin to high level, set it to low level after a 5 ms delay, successfully display a character, the cursor automatically moves one position backward, and define the next character.

10. The measuring method of the automatic moment of inertia measuring device according to claim 7, characterized in that: After the time data in the main chip and the current magnitude data in the sub-chip in process e of step S4 are collected, they are transmitted to the main chip for joint operation. The main chip and the sub-chip achieve common change of levels through eight one-way information transmission channels with NOT gate structures.

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