In my recent work, I need to measure the position, velocity and rotation angle of a moving platform in a 3-DOF parallel manipulator.
The simplest way is to use a incremental quadrature encoder allied with a microcontrolled system. The measure of position, velocity and rotation angle can be calculated by software. The microcontroller count the number of pulses of the encoder and then can calculate position, velocity and rotation angle. The direction of rotation can be detected too.
There are a lot of commercial incremental quadrature encoders that you can find. The price changes with the number of pulses per revolution (the resolution).
You might consider an MPU like the Invensense (http://www.invensense.com/mems/gyro/mpu9150.html), available for prototyping (https://www.sparkfun.com/products/11486). If you do, let me know how well it works - I've been thinking of integrating one in a smart camera.
First of all, thank all of you for your kindly answers!
In my case, I need to measure the position, velocity and the rotation angle of the center of the platform in my prototype, and now in our labrotory, I just can measure the linear acceleration, angular velocity of the platform by Phidget Spatial Sensors, and the noisy is a little bit too large. I tried to compute the the displacement, velocity and the rotation angle by the measured result, however, it's so hard to get accuracy answers.
With comparing your suggestions, I think the Phidget Spatial sensor is similar with MPU sensor suggested by Prof. Sam Siewert, am I right, Prof. Sam Siewert? Regarding to IMU sensors, I don't think it is suitable for my prototype, since the measured platform is a thin aluminium alloy plate and the sensor size is too big, isn't it??? Regarding to a incremental quadrature encoder, I have no idea about it yet, could you please give me more information about the brand of the commercial sensors?
IMU sensors are a suitable option in general but you will need to mess around with sensor fusion for getting proper results if you are using simple sensors. You should try the already mentioned Invense MPU-9150 or MPU-60X0 series, because they have an integrated hardware sensor fusion algorithm.
We are using incremental optical encoders. They are very cheap and easy to mount
Incremental rotary encoder is the best for speed measurement whereas absolute encoder is for position measurement. check direct industry website for industrial grade sensors
For stabilization and control usually I use encoders and giroscops but if you have problems check Xsens http://www.xsens.com/
Xsens is the leading innovator in 3D motion tracking technology and products. Its sensor fusion technologies enable a seamless interaction between the physical and the digital world in consumer devices and professional applications such as 3D character animation, motion analysis, and industrial control & stabilization.
Perhaps it will be the best solution for you
For measure angular position and velocity, a very robust and extremely low cost solution is a hall-effect based absolute encoder, of course it can be used as a relative one in order to measure velocity.
The models AS5045 (12 bits) or AS5048 (14 bits), are suitable for your work, the manufacturer is Austriamicrosystems, also you can request some free samples.
Their size is tiny, due to the TSSOP-20 package.
I hope this answer can help you!
The best IMU with all built-in (no need for additional filtering/drift removal etc)
http://www.microstrain.com/inertial/3DM-GX3-25
Check that out. It's a simple cheap solution for general mobile robots, not limited to multi-engine aerial kits:
http://www.multiwiicopter.com/products/paris-sirius-v4r6-usb
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