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CN-122024565-A - Modularized middle school physical and mechanical experiment measurement and control system and centripetal force experiment method

CN122024565ACN 122024565 ACN122024565 ACN 122024565ACN-122024565-A

Abstract

The invention discloses a modularized physical and mechanical experiment measurement and control system and a centripetal force experiment method for a middle school, and belongs to the technical field of physical experiment teaching equipment for the middle school. The measurement and control system comprises a rotation and speed measurement module and a tension measurement module which can work independently and can be combined flexibly, wherein the rotation and speed measurement module takes an STM32 singlechip as a core, the rotation and speed measurement module realizes accurate measurement and control of rotating speed through orthogonal pulse acquisition, 4 frequency multiplication processing and M method speed measurement of a Hall encoder, and the tension measurement module realizes accurate acquisition of tension through a tension sensor and a 24-bit high-precision AD conversion chip. The core of the invention adopts modularized modular design, two modules can be independently adapted to various mechanical experiments, and can also be used for integrally constructing a centripetal force experiment platform, and the verification of a centripetal force formula is completed through a matched experiment method. The invention solves the problems of poor universality and complex operation of the traditional experimental equipment, simplifies and focuses the scheme, and has extremely strong practicability and patent authority.

Inventors

  • CHEN ZHIJIE

Assignees

  • 陈志杰

Dates

Publication Date
20260512
Application Date
20260301

Claims (6)

  1. 1. A modularized middle school physical mechanics experiment measurement and control system is characterized by comprising a rotation and speed measurement module and a tension measurement module, wherein the rotation and speed measurement module and the tension measurement module can work independently and can also be flexibly assembled and matched with different mechanics experiments, the rotation and speed measurement module takes an STM32 singlechip as a control core and comprises a deceleration direct current motor with a Hall encoder, an L298N motor driving unit, an OLED display unit and a power supply unit, the deceleration direct current motor with the Hall encoder outputs A, B two-phase orthogonal pulse signals, the STM32 singlechip collects the orthogonal pulse signals through an encoder interface mode of a timer and obtains real-time rotation speed through M method speed measurement calculation after 4 times frequency multiplication processing, the STM32 singlechip is connected with the L298N motor driving unit through PWM signals to realize linear adjustment and forward and reverse rotation control of the motor rotation speed, the OLED display unit is in communication connection with the STM32 singlechip and is used for displaying rotation speed data in real time, the tension measurement module takes the STM32 singlechip as a control core and comprises a tension sensor, an OLED display unit and an AD conversion unit with high precision 24 bits, an OLED display unit and a power supply unit, an analog signal output end of the tension sensor is connected with the HX conversion unit, and the STM 711 AD conversion unit is connected with the STM 711 and the STM32 singlechip 32, and the STM32 is in communication with the communication port 32.
  2. 2. The modularized middle school physical mechanics experiment measurement and control system according to claim 1, wherein the calculation formula of the rotation and speed measurement module for measuring the speed by adopting an M method is that n=count/(PPR_total×Ts), wherein n is the rotation speed of an output shaft of a motor, the unit is RPM, count is the total pulse Count output by an encoder in a sampling period Ts, ts is a fixed sampling period, and PPR_total is the total pulse number corresponding to one rotation of the output shaft of the motor.
  3. 3. The modularized middle school physical mechanics experiment measurement and control system according to claim 2, wherein the calculation formula of the PPR_total is PPR_total=encoder PPR×reduction ratio×4, wherein the encoder PPR is a single-way complete square wave number output by one-turn rotation of a main shaft of the encoder, the reduction ratio is a transmission ratio of a speed reduction direct current motor, and 4 is a 4-frequency multiplication multiple of an STM32 single-chip microcomputer orthogonal coding mode.
  4. 4. The modular middle school physical mechanics experiment measurement and control system according to claim 1, wherein the tension measurement range of the tension measurement module is 0-30N, the STM32 singlechip reads 24-bit AD conversion data of the HX711 unit through time sequence driving, and the real-time tension value is obtained through conversion after no-load gross weight is deducted.
  5. 5. S1, integrating and constructing a system, namely connecting a speed reduction direct current motor of a rotation and speed measurement module with a rotation bearing in a transmission way, and fixing a horizontal cross rod on the rotation bearing to synchronously rotate along with the rotation bearing; the method comprises the steps of fixing a tension sensor of a tension measuring module at a rotating end of a rotating bearing, connecting a stress end of the tension sensor with a cylindrical rotating animal block sleeved on a horizontal cross rod to finish building a centripetal force experiment platform, S2, preparing for experiments, measuring the mass m of the cylindrical rotating animal block, adjusting the position of the rotating animal block on the horizontal cross rod, fixing and measuring a rotating radius r, carrying out no-load calibration on the tension measuring module to finish tension clearing, S3, collecting data, starting a rotating and speed measuring module, adjusting a motor to a stable rotating speed, recording an average rotating speed n measured by the rotating and speed measuring module, recording a real-time measured value F of the tension measuring module, S4, verifying a formula, substituting the measured values m, r and n into a centripetal force formula f=4pi 2n2mr, calculating to obtain a theoretical centripetal force value, comparing the theoretical value with the pulling force F, calculating experiment errors, and finishing verification of the centripetal force formula, S5, carrying out variable comparison experiments, namely respectively changing the mass m of the rotating animal block, the rotating radius r and the rotating speed n of the motor, and repeating steps S3-S4, and finishing a plurality of groups of comparison experiments.
  6. 6. The centripetal force test method according to claim 5, wherein in said step S1, a rotation radius adjustment range of the rotating mass is 0.12m to 0.17m.

Description

Modularized middle school physical and mechanical experiment measurement and control system and centripetal force experiment method Technical Field The invention relates to the technical field of middle school physics experiment teaching equipment, in particular to a modularized middle school physics mechanics experiment measurement and control system and a centripetal force experiment method. Background In a physical mechanics teaching system of middle school, circular motion and centripetal force experiments are essential experiments, and are key carriers for students to understand mechanics laws. In the prior art, the middle school physics centripetal force experimental equipment mainly has the following core defects: Most of the equipment is of an integrated special structure, has single function, cannot be disassembled to be matched with other mechanical experiments for universal components, has extremely low equipment utilization rate, and cannot meet the requirements of multi-scene teaching; The traditional equipment is driven by hand or common electric drive, lacks an accurate rotating speed measuring and controlling device, cannot be stably controlled and accurately collected, has unstable experimental phenomenon, and is difficult for students to quickly observe the corresponding relation between centripetal force and each variable; The high-precision force measuring device is lacking, students can only obtain data through visual inspection or rough reading of the spring balance, the experimental error is large, and the accuracy of a centripetal force formula cannot be accurately verified; the equipment is complex in operation, cannot adapt to a novel teaching mode of the current virtual simulation and physical experiment fusion, and a teacher cannot flexibly select an experiment scheme to develop teaching. Disclosure of Invention Aiming at the defects of the prior art, the invention aims to provide a modularized middle school physical mechanics experiment measurement and control system and a centripetal force experiment method, and the independent use and flexible combination of a rotating speed and a tension measurement module are realized through modularized and modularized design, so that the problem of poor universality of traditional equipment is solved, and meanwhile, an integrated use method based on the modularized system is provided, the convenient development of the centripetal force experiment is realized, and the teaching effect is improved. Technical proposal In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: in a first aspect, the invention provides a modularized middle school physical mechanics experiment measurement and control system, which comprises a rotation and speed measurement module and a tension measurement module which can work independently and can also be flexibly combined to be matched with different mechanics experiments. The rotation and speed measurement module takes an STM32 singlechip as a control core and comprises a deceleration direct current motor with a Hall encoder, an L298N motor driving unit, an OLED display unit and a power supply unit. The speed-reducing direct current motor with the Hall encoder can output A, B two-phase orthogonal pulse signals, the STM32 singlechip collects the orthogonal pulse signals through an encoder interface mode of the timer, the real-time rotating speed of the motor is obtained through speed measurement calculation by an M method after the measuring resolution is improved through frequency multiplication processing by 4, the STM32 singlechip realizes linear adjustment and forward and reverse rotation control of the rotating speed of the motor by outputting PWM signals to an L298N motor driving unit, and an OLED display unit is in communication connection with the STM32 singlechip and displays rotating speed data in real time, so that experimental observation and reading are facilitated. Further, the rotation and speed measurement module calculates the rotation speed by adopting a frequency measurement method (M method), wherein a core formula is n=count/(PPR_total×Ts), n is the rotation speed (RPM) of the motor output shaft, count is the total pulse Count output by the encoder in a sampling period Ts, ts is a fixed sampling period, and PPR_total is the total pulse Count corresponding to one rotation of the motor output shaft. Further, the PPR_total is determined by three factors of inherent precision of the encoder, motor reduction ratio and 4 times frequency multiplication, wherein a calculation formula is that PPR_total=encoder PPR×reduction ratio×4, and rotation speed measurement resolution is improved by 4 times on the premise of not increasing hardware cost by 4 times frequency multiplication, so that measurement precision is ensured. The tension measurement module takes an STM32 singlechip as a control core and comprises a tension sensor, an HX711 high-precision 24-bit AD