CN102680725A - System and method for measuring wheel speed of single-axis gyroscope - Google Patents

Abstract

A single-axis gyro wheel speed measurement system and method, the system axis gyro collects the angular velocity of the wheel and converts it into a voltage parameter and sends it to the AD conversion module of the microprocessor, and then the microprocessor passes the data through the serial port/SIP interface Pass it to the wireless transmitting module, and finally send the data out by the wireless transmitting module. The method includes: 1. The single-axis gyro is installed on the wheel shaft at a certain inclination angle, and the measurement range of the single-axis gyro is increased by using the projection of the single-axis gyro in the direction of the wheel shaft. , the single-axis gyroscope converts the angular velocity of the wheel into the corresponding voltage parameter, and then transmits it to the microprocessor through the AD conversion module; 3: the microprocessor converts the received voltage parameter into a digital value, and saves the data in the In the external memory; 4: After receiving the data upload instruction, the wireless transmission module sends the data through the 2.4GHz wireless frequency band.

Description

Single-axis gyroscope wheel speed measurement system and method

technical field

The invention relates to a system and method for measuring the rotational speed of a wheel based on a single-axis gyroscope, in particular to a method for measuring the rotational speed of a wheel after increasing the measuring range of the gyroscope.

Background technique

With the rapid development of road transportation, the characteristics of high load capacity, economy and efficiency of automobile trains have attracted the attention of the industry, and they have gradually become the main models of long-distance logistics. The study of brake coordination of automobile trains is of great significance to the safe driving and standard operation of automobile trains. It is an effective method to study the coordination of braking by measuring and recording the wheel speed of each wheel during the braking process of automobile trains, observing the curve of each wheel speed changing with time, and measuring the braking coordination time of each axis. So how to quickly and accurately measure the wheel speed is the basis of this research method.

There are many methods for measuring the wheel speed, which can be generally divided into two categories: one is the direct method, that is, directly observes the mechanical movement of the machine or the motor, and measures the number of turns of the mechanical rotation within a specific time, thereby measuring the speed of the mechanical movement; the other One is the indirect method, which measures the changes of other physical quantities due to mechanical rotation, and obtains the rotational speed from the relationship between the changes of these physical quantities and the rotational speed. At present, the commonly used speed measurement methods at home and abroad include photoelectric code disc speed measurement method, Hall element speed measurement method, centrifugal tachometer measurement method, tachometer generator speed measurement method, magnetic speed measurement method and flash speed measurement method. These methods have their own advantages and disadvantages: the structure of the photoelectric code disc is simple and the price is cheap, but it cannot work continuously for a long time and is easily damaged; the Hall element has high sensitivity and small size, but the interchangeability is poor, the signal changes with temperature, and it is a nonlinear output , needs nonlinear and temperature correction; the centrifugal measurement method is accurate and intuitive, and the equipment is reliable and durable, but its structure is more complicated; the tachogenerator needs some modifications to the internal structure of the car, and the operation is complicated; Small, but the anti-interference ability is poor, the output signal is not standard; the flash method can measure the speed of very small objects or in the position that cannot be approached, but the price is expensive.

Contents of the invention

Aiming at the above problems, the present invention combines the actual working condition requirements of the research on the coordination of brakes and brakes of automobiles and trains, uses a wheel speed measurement system and method based on a single-axis gyroscope, and aims at the shortcoming of a single-axis gyroscope with a narrow measurement range. A method for enlarging the measuring range of a gyroscope has the characteristics of simple structure, convenient installation, accurate measurement and the like.

In order to solve the above problems, the present invention provides a wheel speed measurement system of a single-axis gyroscope, which is characterized in that: it includes a MEMS gyroscope, that is, a single-axis gyroscope, and also includes a microprocessor and a wireless transmission module;

The MEMS gyroscope collects the angular velocity of the wheel, converts it into a voltage parameter and sends it to the AD conversion module of the microprocessor, and then the microprocessor transmits the data to the wireless transmission module through the serial port/SIP interface, and finally the wireless transmission module sends the data out , displayed by a computer or instrument.

The method for measuring the wheel speed of a uniaxial gyroscope is characterized in that it comprises the following steps:

The first step: the single-axis gyro is installed on the wheel shaft with an inclination angle θ, that is, the deflection angle of the single-axis gyro and the wheel shaft, and the measurement range of the single-axis gyro 1 is increased by using the projection of the single-axis gyro in the direction of the wheel shaft ;

Step 2: After the wireless transmission module receives the acquisition command, the single-axis gyro 1 converts the angular velocity of the wheel into the corresponding voltage parameter, and then transmits it to the microprocessor through the AD conversion module;

Step 3: The microprocessor converts the received voltage parameters into digital values, and saves the data in the external memory after internal processing;

Step 4: After receiving the data upload command, the wireless transmitting module sends the data through the 2.4GHz wireless frequency band.

Finally, the terminal module in the car instrument will receive, process and display the wheel speed.

。 As described in the first step, the rotational speed of the wheel sensed by the uniaxial gyro is ω*cosθ, that is, the projection of the rotational speed of the uniaxial gyro on the rotational axis of the wheel, where ω is the rotational angular velocity of the wheel; as long as the inclination angle θ is adjusted to a suitable The value can measure high speed, and the tilt angle θ is determined by the following formula:

.

Beneficial effects: the present invention applies the single-axis gyroscope to the measurement of the rotation speed of the wheel, and solves the problem that the range of the gyroscope is too narrow. The single-axis gyroscope can measure the angular velocity moving along one axis or several axes, and the angular velocity measured by the single-axis gyroscope has extremely high precision and response speed. Compared with the traditional speed measurement method, it can measure extremely low wheel speed and has a simple structure. The invention transmits data through the wireless transmitting module, reduces the connecting wiring harness in the vehicle body, and has the advantages of small size, strong anti-interference ability, convenient installation and the like.

Description of drawings

Fig. 1 is the structural representation of the system of the present invention;

Figure 2 is a schematic diagram of the installation of the deviation angle of the gyroscope;

Figure 3 shows the linear relationship between voltage and speed.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figure 1, the wheel speed measurement system of the single-axis gyroscope includes a MEMS gyroscope (that is, a single-axis gyroscope), a microprocessor, and a (long-distance) wireless transmission module;

The MEMS gyroscope (that is, single-axis gyroscope) collects the angular velocity of the wheel, converts it into a voltage parameter and sends it to the AD conversion module of the microprocessor, and then the microprocessor transmits the data to the wireless transmission module through the serial port/SIP interface, and finally the The wireless transmitting module sends out the data, which is displayed by the computer or the instrument.

As shown in Fig. 1 and Fig. 2, the method for measuring the wheel speed of the uniaxial gyroscope comprises the following steps:

Step 1: The single-axis gyro 1 is installed on the wheel shaft 2 at an inclination angle θ (that is, the deflection angle between the single-axis gyro 1 and the wheel shaft 2), and the projection of the single-axis gyro 1 on the direction of the wheel shaft 2 is used to increase the single-axis Measuring range of axis gyro 1;

Step 2: After the wireless transmission module receives the acquisition command, the single-axis gyro 1 converts the angular velocity of the wheel into the corresponding voltage parameter, and then transmits it to the microprocessor through the AD conversion module;

Step 3: The microprocessor converts the received voltage parameters into digital values, and saves the data in the external memory after internal processing;

Step 4: After receiving the data upload command, the wireless transmitting module sends the data through the 2.4GHz wireless frequency band.

Finally, the terminal module in the car instrument will receive, process and display the wheel speed.

。 As described in the first step, the rotational speed of the wheel sensed by the single-axis gyro 1 at this time is ω*cosθ (ω is the rotational angular velocity of the wheel), that is, the projection of the rotational speed of the single-axis gyro 1 on the rotational axis 2 of the wheel, as long as the inclination angle θ can be adjusted to a suitable value to measure high speed; for example, the diameter of a truck wheel is 1 meter, and the speed is 80 km/h. At this time, the wheel rotates about 7 times per second, and the range of ordinary MEMS gyroscope is about 200°/s. Then the gyroscope and the wheel axis need to be deflected by about 86°, that is, the inclination angle θ is 86°. The tilt angle θ is determined by the following formula:

.

The MEMS gyroscope rotates with the wheel, senses the Coriolis force of its own rotation, and uses the Coriolis principle to convert the angular velocity applied by the input part of the MEMS gyroscope into a voltage parameter that can be detected by a dedicated circuit. This voltage signal has a linear relationship with the speed of the wheel, as shown in Figure 3. When the gyro reaches the maximum forward speed, the output voltage value is about 4.75V, and when the gyro reverse speed reaches the maximum speed, the output voltage value is about 0.25V V.

The above descriptions are only preferred embodiments of the present invention, and are not limited to the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of the claims of the present invention.

Claims (3)

1. the vehicle wheel rotational speed measuring system of single shaft gyro, it is characterized in that: comprise the MEMS gyroscope, promptly the single shaft gyro also comprises microprocessor, wireless transmitter module; The angular velocity that the MEMS gyroscope is gathered wheel is transformed to the AD modular converter that voltage parameter is sent to microprocessor with it; Through serial ports/SIP interface data are passed to wireless transmitter module by microprocessor again; By wireless transmitter module data are sent at last, show by computing machine or instrument.

2. the vehicle wheel rotational speed measuring method of single shaft gyro is characterized in that: may further comprise the steps:

The first step: single shaft gyro (1) is with tilt angle theta; It is the deflection angle of single shaft gyro (1) and rotation shaft of wheel (2); Be installed on the rotation shaft of wheel (2), utilize single shaft gyro (1) to increase the measurement range of single shaft gyro (1) in the projection of rotation shaft of wheel (2) direction ;

Second step: wireless transmitter module is after receiving acquisition instructions, and single shaft gyro (1) converts the angular velocity of wheel to corresponding voltage parameter, passes to microprocessor through the AD modular converter again;

The 3rd step: microprocessor converts the voltage parameter that receives to digital value, after inter-process, saves the data in the external memory storage;

The 4th step: wireless transmitter module sends the radio band of data through 2.4gHz after receiving the data upload instruction;

Last terminal module in automobile instrument will receive, handles and show vehicle wheel rotational speed.

3. the vehicle wheel rotational speed measuring method of single shaft gyro according to claim 2; It is characterized in that: of the first step; The vehicle wheel rotational speed of single shaft gyro (1) institute perception is ω * cos θ; Be the projection of single shaft gyro (1) rotational speed on rotation shaft of wheel (2), wherein ω is the rotational angular velocity of wheel; As long as tilt angle theta is adjusted to suitable value with regard to the high rotating speed of energy measurement, tilt angle theta is confirmed through following formula: .

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