Pololu-Zumo-Shield-Arduino-seneur-inertiel

Introduction

Le shield Zumo inclus des senseurs inertiels sur la carte. Ces senseurs peuvent être utilisés pour des applications avancées comme détecter des collisions et déterminer sa propre orientation.

Tous les versin du shield Zumo comporte une boussole qui combine un accéléromètre 3 axes et un magnétomètre 3 axes dans une seule puce interfacée sur le bus I2C. Cette puce est le LSM303D lien pololu sur un shield v1.2 ou un LSM303DLHC lien pololu on the sur le shield Zumo original.

La version v1.2 inclus également un gyroscope 3 axes L3GD20H lien pololu également interfacé sur le bus I2C.

Pololu recommande la lecture de la Fiche technique LSM303D (1MB pdf, pololu), Fiche technique L3GD20H (3MB pdf, pololu), et/ou fiche technique LSM303DLHC (629k pdf, pololu) pour comprendre comment fonctionne les senseurs afin de savoir comment les utiliser.

Utiliser les senseurs

Level shifters built into the shield allow the inertial sensors, which operate at 3.3 V, to be connected to the 5 V logic level pins of the Arduino. The sensors, level shifters, and I²C pull-up resistors are connected to the SCL and SDA pins on the Zumo Shield by default, but they can be disconnected by cutting traces to allow those pins to be used for other purposes. It is necessary to make some additional connections on the shield if you want to use the compass with an older Arduino without separate SCL and SDA pins; please see Section 3.c for more details about the compass connections.

We have written a basic LSM303 Arduino library and L3G Arduino library that makes it easier to interface the sensors with an Arduino, as well as an example project that demonstrates how to use the magnetometer to help the Zumo coordinate its turns.

In addition, the combination of accelerometer, magnetometer, and gyro on the v1.2 version of the Zumo Shield is enough to implement an inertial measurement unit (IMU); the sensor ICs are the same as those on our MinIMU-9 v3, so Arduino software written for the MinIMU-9 lien pololu (such as our AHRS example) can also be adapted to work on an Arduino-controlled Zumo robot with a v1.2 shield.

Notes sur le magnétomètre

Please note that the magnetometer in the LSM303 is affected by currents in the motors and buzzer when they are operating, as well as metal in the batteries, and the readings are easily influenced by magnetic distortions in the environment around the Zumo (such as rebar in a concrete floor). As a result, it is very hard to accurately determine the Zumo’s absolute heading based on the magnetometer data. However, in our tests, we found that the magnetometer was still useful for detecting relative orientation changes; for example, once the magnetic readings are compensated for a particular environment, they can be used to help the Zumo turn left or right by a specific angle instead of just timing how long to run the motors to make such a turn.

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Basé sur "Zumo Shield for Arduino" de Pololu (www.pololu.com/docs/0J57) - Traduit en Français par shop.mchobby.be CC-BY-SA pour la traduction
Toute copie doit contenir ce crédit, lien vers cette page et la section "crédit de traduction". Traduit avec l'autorisation expresse de Pololu (www.pololu.com)

Based on "Zumo Shield for Arduino" from Pololu (www.pololu.com/docs/0J57) - Translated to French by shop.mchobby.be CC-BY-SA for the translation
Copies must includes this credit, link to this page and the section "crédit de traduction" (translation credit). Translated with the Pololu's authorization (www.pololu.com)