The three-axis accelerometer MMA7260Q can measure the inertia of the smart car, select the best center of gravity position, and accurately locate the smart car in running state such as straight line, curve, ramp, drift; use the acceleration sensor to predict the path ahead and determine when The brakes work best. And it is a good solution to the balance and direction identification of the upright walking car model.
Therefore, a design based on three-axis acceleration sensor in smart car and path recognition is proposed. The design uses the three-axis accelerometer MMA7260Q to measure the acceleration signal of the smart car in motion. The embedded single chip MC9S12XSl28B is used as the core controller to sample the acceleration signal, A/D conversion, and then store the feature data in the EEPROM. The problem of smart car motion path analysis is well solved. The acceleration of the car is obtained in real time, so that the running state of the car is more comprehensively obtained, which provides the possibility of controlling the fluency and better road condition recognition.
In the car model that is walking upright, applying the same principle and selecting the best center of gravity can well solve the balance and direction recognition of the upright walking car model, thereby speeding up the driving speed of the car model.
The experimental results prove that the combination of the acceleration sensor has strong anti-interference and the extraction angle information is more accurate, which ensures that the smart car can drive at a higher speed on the straight road, and can bend smoothly without stalling in the curve.
1. Existing problems with smart cars
In the operation of the car model, people can not judge the running state of the car, use the acceleration sensor to monitor the acceleration of the car, so that the running state of the car can be more accurately known, and the ramp can be distinguished by detecting the change of acceleration in a certain direction. And non-ramp. Therefore, the corresponding strategy response is carried out. Avoid parking and rollover during the race. And the balance in the walking process of the car model in the upright walking is well solved.
2. Introduction to MMA7260Q
The acceleration sensor is the MMA7260Q from Freescale.
Figure 1 chip pin definition
2.1 Features of the MMA7260Q:
Provides three-axis XYZ detection sensitivity in one device, optional sensitivity: 1.5g, 2g, 4g and 6g; low power consumption, sleep mode, low voltage operation is generally 2.2V~3.6V, can start quickly, general startup time It is 1ms; its low noise, the package is usually a 16-pin 6mm x 6mm x 1.45mm pinless rectangular package (QFN).
2.2 Advantages of MMA7260Q
Flexible range for flexible applications: 1.5g, 2g, 4g and 6g; low power consumption for extended battery life Short start-up response time, ideal for sleep mode in battery-powered handheld devices, low component count - saving Low cost and space noise, high sensitivity, adaptive function, high frequency and resolution, providing accurate fall, tilt, move, placement, vibration and rocking sensitivity. Recommended gravity acceleration level free fall detection for different applications: 1g~2g Tilt control: 1g~2g.
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