# gtMultirotores

Member Since: January 17, 2014

Country: Guatemala

## Profile

Rotation matrices are used to define a rotation in a given axis. The most important properties a rotation matrix has are:

They have unitary vectors in all of their rows or columns They have a determinant of 1 the normalization of a rotation matrix is always 1 Its orthogonal If its orthogonal its transpose is equal to its inverse.

We can denote a rotation matrix as:

matriz de rotacion

The next image shows what a rotation by an angle of theta does to a coordinate frame. rotacion

Now that you know what a rotation matrix is and does you have to ask yourself “What purpose does it have in robotics?”, the answer to that question is that the rotation matrix defines a rigid objects rotation on a given axis. If we dig further in we can define what local and global frames are.

The global frame is the reference coordinate frame in which the rest of the robot rotates or translates. in the case of a robot arm the local frames would be the joints that rotate and translates and finally give the end effector its position due to its total spatial displacement.

The transofrmation of a global coordinate frame to a local frame depends of the axis the rotation. The transformations for x,y,z axis rotations are shown below:

Rotacion a lo largo del eje X

Rotacion a lo largo del eje Y

Rotacion a lo largo del eje Z

As I previously stated rotation matrices are unitary so its transformation is also unitary therefor its transpose is also equal to its inverse. The process of the transformation from global to local coordinate frames is given below in which R is the rotation matrix along an axis and Puvw is the local coordinate frame point in space.

transformacion de locales a globales

When we clear R we would normally get 1/R but we actually know that 1/(any matrix) is equal to the inverse of the matrix. Recalling that the inverse is equal to the transpose in unitary matrices we get the next transformation.

Locales a globales final

David Rodriguez

owner of http://www.multirotorguides.com

Multirotor fanatic

• any help i dont know how to access my BBB terminal i really need the help i tried mousers startup guide but my BBB doesnt give me any gateOne SSH option

• Is it posible to program this with FTDI programmer and the native C of the microcontroller?, if so can anyone help me with it?

• is this literally one per costumer or 1 per order im a little confused

• is this literally one per costumer or 1 per order im a little confused, because i would really love to buy another one for a CNC milling machine.

• is this beaglebone compatible?

• is this usable with beaglebone black?

• can the beaglebone connect and talk to sensors like a 10dof breakout board like http://www.amazon.com/L3G4200D-ADXL345-HMC5883L-BMP085-Breakout/dp/B008G7T3QQ/ref=pd_sxp_grid_pt_0_1 without using an external arduino? ive got this question because ive got a project and im gonna use bbb because i need a much powerful platform than an arduino for the project but i really need this sensor to work.

No public wish lists :(

In 2003, CU student Nate Seidle blew a power supply in his dorm room and, in lieu of a way to order easy replacements, decided to start his own company. Since then, SparkFun has been committed to sustainably helping our world achieve electronics literacy from our headquarters in Boulder, Colorado.

No matter your vision, SparkFun's products and resources are designed to make the world of electronics more accessible. In addition to over 2,000 open source components and widgets, SparkFun offers curriculum, training and online tutorials designed to help demystify the wonderful world of embedded electronics. We're here to help you start something.