7
votes
Use data from gyroscope to calculate orientation
gyroscopes do not measure [dRoll ,...] they measure body rates. These are not the same things. There is a transformation matrix ( that I do not have on hand) that relates body rates to euler rates. ...
- 1,853
6
votes
Accepted
Stabilising an inverted pendulum
There are lots of ways to solve this problem, which falls into the category of Control Engineering. There are two standard approaches:
Classical Control: The control command has to be proportional ...
- 1,268
5
votes
What does "6 degrees of freedom" mean?
Most "meters" of all varieties include up to three degrees of freedom simply to observe all three dimensions of reality we find ourselves in.
That said, every object in our three space has three ...
- 95
4
votes
Accepted
Angular velocities and rotation matrices
If your object $O$ has a different orientation from your global frame $S$, and you know what that difference in orientation is, you can create a 4x4 transform matrix between the two:
$$
T = \left[ \...
- 16k
4
votes
Accepted
Complimentary filter issues
There are quite a few things wrong here. I'll split them into two sections: technical errors, and coding warnings.
Technical Errors:
You are not calculating your angles from accelerometer readings ...
- 16k
4
votes
Accepted
Is there a commercially available inertial gyro with electronic control?
The device you describe is known as a Control Moment Gyroscope (CMG). These devices are mostly used for attitude control in spacecraft, but are also commercially available.
- 562
3
votes
Accepted
Localising a robot placed at an unknown position in a known environment
The problem is that you can't apply path planning until you know where the robot is in the global coordinate frame. There are many localization techniques, and each has its pros/cons; I have used ...
- 926
3
votes
Accepted
Can I use a 3D gimbal system as a simplistic quadcopter IMU(3 axis accelerometer)?
A gimbal system will not replace an accelerometer. I assume by gimbal system you mean something like a Gyroscope, i.e. a device that has a fixed orientation allowing you to measure your orientation ...
- 218
3
votes
Stabilising an inverted pendulum
The theory that describes what you are looking for is call Control Theory. Search for the Nonlinear Systems textbook by Hassan Khalil for an excellent overview of the material--the inverted pendulum ...
- 926
3
votes
Is there a way to measure 3 axis orientation without a magnetometer?
Calibration procedures for magnetometers exist, to compensate for soft iron (nearby ferromagnetic objects) and hard iron (nearby magnetic fields) offsets, which skew the measurements. However, these ...
- 550
3
votes
How to calculate Euler Angles from gyroscope output?
Using the Gyroscope
First thing to note is that the gyroscope is reporting angular rates with respect to the sensor. So if the sensor is rotating with some rate, the data it's outputting will be in ...
3
votes
Filtering angular velocity spikes of a cheap Gyroscope
You gave the part number and protocol, but
Can you provide a schematic for how this is installed in a circuit?
Are you using the module or an individual chip?
Is this all soldered together or is it ...
- 16k
3
votes
Compensation for IMU mounting misalignment
You need the transformation from the car to the IMU.
You can get this by recording the IMU published attitude with the car in known orientations.
You should be able to construct the IMU to car ...
- 1,853
3
votes
angular velocity output of IMU
1) An inertial frame is one in which a free particle travels in a straight line at constant speed, or is at rest. Practically speaking, you usually check if a frame is inertial or not by ...
- 331
3
votes
Data collected from ROS
As Ben noticed, you may want to elaborate on your question, but in general data collection in ROS is performed using tools from the rosbag package.
As you'll find when you read the documentation, ...
- 1,353
2
votes
Accepted
Quadrocopter problem with stability
You have far too much vibration reaching your sensors. Mount the board you're using with vibration damping mounts, this should solve most of your problem. An easy way to do this is to attach each ...
- 1,853
2
votes
How to interrupt on a data ready trigger when communications to the sensor are interrupt driven?
I'm using the L3GD20H MEMS gyroscope with an Arduino ...
How is the sensor's interrupt line intended to be used if the
microcontroller can't handle the interrupt from an ISR using an
interrupt-...
- 4,525
2
votes
Accepted
How to interrupt on a data ready trigger when communications to the sensor are interrupt driven?
I think you have a false assumption somewhere. A very quick scan through the atmel datasheet and arduino twi.c does not show any problems.
Why do you think the microcontroller can't handle the ...
- 4,385
2
votes
What does "6 degrees of freedom" mean?
To understand what these gyroscopes and accelerometers are measuring, you first need to know the physics and geometry behind "Degrees of Freedom". In terms of physics, each degree of freedom (DoF) in ...
- 378
2
votes
What does "6 degrees of freedom" mean?
In IMUs, the number of degree of freedom is the number of independent readings they can do.
For 9 DOF IMU it is typically 3 for the accelerometer, then 3 for the gyroscope and 3 others for the ...
- 571
2
votes
What does "6 degrees of freedom" mean?
n degrees of freedom of an object means it requires n unique parameters to completely define itself. For eg., a 3-DOF arm requires 3 joint parameters with which each and every position on the arm can ...
- 173
2
votes
Use data from gyroscope to calculate orientation
Short answer: A gyroscope by itself cannot determine its global reference frame. You either need to start the device in a known initial global orientation and measure how much the orientation changes, ...
- 121
2
votes
Should I use gyro or encoders for robot moving in straight line?
The problem here is that you are trying to drive in a straight line without any external reference. Wheels slip (making encoders give error), gyro's drive (so there's error there to), magnetometers ...
- 151
2
votes
Localising a robot placed at an unknown position in a known environment
There are many tactics for localization in a known environment. the most popular ones are the Filtering methods which include Kalman filtering and Particle filtering. Nowadays the second one is the ...
- 400
2
votes
Accepted
Pitch angle is either +90° or -90°
The problem is that the quaternions given in
id: 4 distance: 1048 q0: 646 q1: -232 q2: -119 q3: 717
are not normalized. In fact,
$$
\|\textbf{q}\| = \sqrt{q_0^2+q_1^2+q_2^2+q_3^2} = 999.6950
$$
I ...
- 385
2
votes
Angles from gyroscope readings using quaternions
I'll link you to some math but try to give a conceptual explanation, too.
Consider a case where you want to start with the IMU upright and pointed forward and want to end with the IMU upside-down (...
- 16k
2
votes
Handling GYROSCOPE BIAS DRIFT
You say,
Then why can't we track [the angles] for first ten seconds and then keep subtracting the present angles from initially calculated angles for every ten seconds during movement?
You can't ...
- 16k
2
votes
How is gyroscope bias exposed and tracked?
I think you're confused. The method you're talking about would only really work if you know the magnitude and orientation of the accelerations you're trying to measure. If that's the case, then why ...
- 16k
2
votes
Convert local coordinates of a moving IMU to global coordinates
It isn't really a problem but a solution rather. The difficult part is pose estimation, comparison just needs to have a transformation between the estimated poses.
There have been research works on ...
- 671
2
votes
What is required to get the roll, pitch and yaw of an aerial vehicle?
The only sustainable long-term acceleration (for anything terrestrial) is gravity. The Madgwick algorithm uses gravity and a magnetometer to correct gyro drift.
Watch the video, then head to the ...
- 16k
Only top scored, non community-wiki answers of a minimum length are eligible