Is a Vibrating Structure Gyroscope the Key to Measuring Vehicle Pitch and Roll?

In summary, the conversation discusses various methods for measuring pitch and roll of a moving vehicle using a 3-axis accelerometer. It is mentioned that most accelerometers only measure translational acceleration and not rotations, and that using two accelerometers at different points on the vehicle can help measure rotation. Other suggestions include using gyroscopes, GPS receivers, barometers, and inertial measurement units. It is also mentioned that measuring pitch and roll while the vehicle is stationary may require different methods.
  • #1
josepvr
3
0
Hello everyone,
i'm new to this forum and this is my first post.
My question is: how to get pitch and roll of a moving vehicle using an 3-axis accelerometer?
accelerometer values are the same when vehicle is stopped?


Thanks in advance.
 
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  • #2
Most accelerometers only measure translational acceleration, not rotations.

If you want to measure a rotation, you need two accelerometers, measuring in the same direction, at different places on the structure, You then get the rotation from the difference in the translations, divided by the distance between the accelerometers.

You can measure pitch and roll with 3 accelerometers at different points on the vehicle, all measuring vertical acceleration, but that is not what a 3-axis accelerometer does.
 
  • #3
Thanks AlephZero,
I've another question, if I only want to measure pitch (inclination angle of the vehicle) are 2 accelerometers required?

I explain you what I'm trying to do. My project consists in measure RC car inclinations when is running uphill/downhill.

If an accelerometer isn't the best solution, could you explain what kind of sensor I might use?
 
  • #4
Airplanes will always use gyroscopes for this. Not sure they can be miniaturized for RC cars though.
 
  • #5
You mean that inclination only can be measured by accelerometer when vehicle is stoped?
 
  • #6
josepvr said:
You mean that inclination only can be measured by accelerometer when vehicle is stoped?

No. Angular rate gyros measure angular acceleration. That is not how fast you are rotating, but how much the rate of rotation changes. If you would like to know the angular position (the inclination) you need to double-integrate.

Integrating the acceleration once gives you the angular rate (degrees per second), and integrating that again gives you the angle.

You need to hold the vehicle still when you calibrate the gyro, otherwise it should work more or less in real-time.

You might look into something like this: http://www.sparkfun.com/products/8955
 
  • #7
And accelerometers measure strictly translational motion, not rotational.
 
  • #8
josepvr, you have a number of solutions
1. You can use 3-degree or 2-degree accelerometer while vehicle is not moving for attitude detection
2. you can use two GPS recievers: one on the front and one on the back of vehicle, and use it's solution to get a pitch angle
3. you can use information about vehicle speed + barometer input %)
4. One GPS receiver and "inertial measurement unit" (3 accelerometer + 3 gyro). This can give you attitude solution.
5. it can be possible to get pitch angle using current speed, current acceleration (from 1-axis accelerometer) and current gas consumption. This can require some preliminary calibration.
 
Last edited:

1. What is an accelerometer pitch and roll?

An accelerometer pitch and roll is a type of sensor used to measure the orientation and movement of an object in three-dimensional space. It measures the pitch, or up and down movement, and the roll, or side-to-side movement, of an object.

2. How does an accelerometer pitch and roll work?

An accelerometer pitch and roll works by using a small mass suspended by springs inside the sensor. When the object moves, the mass also moves and this movement is converted into an electrical signal that can be measured and interpreted.

3. What are the applications of accelerometer pitch and roll?

Accelerometer pitch and roll is commonly used in devices such as smartphones, drones, and gaming controllers to detect movement and orientation. It is also used in navigation systems, aircrafts, and automobiles for stability control and navigation.

4. How accurate is an accelerometer pitch and roll?

The accuracy of an accelerometer pitch and roll depends on various factors such as the quality of the sensor, the calibration process, and external factors like temperature and vibrations. Generally, it has an accuracy of around 0.1 degrees.

5. Can an accelerometer pitch and roll be used in harsh environments?

Yes, there are ruggedized versions of accelerometer pitch and roll sensors that are designed to withstand harsh environments such as extreme temperatures, vibrations, and shock. These sensors are commonly used in military and industrial applications.

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