robotics

How can I calculate the roll, pitch and yaw angles associated with a homogeneous transformation matrix? I am using the following formulas at the moment, but I am not sure whether they are correct or not. pitch = atan2( -r20, sqrt(r21*r21+r22*r22) ); yaw = atan2( r10, r00 ); roll = atan2( r21, r22 ); r10 means second row and first column. Your equations are correct only if the order of rotations is: roll, then pitch, then yaw. For the record, the correspondence with Euler angles (with respect to the frame of reference implicitly given with the transformation matrix) is as follows: Roll is the

In the figure below the goal is to compute the homography matrix H which transforms the points a1 a2 a3 a4 to their counterparts b1 b2 b3 b4. That is: [b1 b2 b3 b4] = H * [a1 a2 a3 a4] What way would you suggest to be the best way to calculate H(3x3). a1...b4 are points in 2D which are represented in homogeneous coordinate systems ( that is [a1_x a1_y 1]', ...). EDIT : For these types of problems we use SVD, So i would like to see how this can be simply done in Matlab. EDIT : Here is how I initially tried to solve it using svd (H=Q/P) in Maltlab. Cosider the following code for the given

I'm tinkering with an iPhone-controlled RC car chassis that is the base of my robotics project . The chassis is controlled with a WiRC Wi-Fi module. It has eight outputs to control electronic speed controllers and servos. I'd like to improve my robot's ability to avoid obstacles using sensors. For this purpose, I have an Arduino board which I can interface with various inexpensive rangefinders and proximity sensors. I'm looking for examples or demo projects that would connect an iPhone to an Arduino board using Bluetooth to send commands to the board and receive data from the board. Is what I

I'm working on a a way to detect the floor in an image. I'm trying to accomplish this by reducing the image to areas of color, and then assuming that the largest area is the floor. (We get to make some pretty extensive assumptions about the environment the robot will operate in) What I'm looking for is some recommendations on algorithms that would be suited to this problem. Any help would be greatly appreciated. Edit: specifically I am looking for an image segmentation algorithm that can reliably extract one area. Everything I've tried (mainly PyrSegmentation) seems to work by reducing the

I am trying to implement Inverse Kinematics on a 2D arm(made up of three sticks with joints). I am able to rotate the lowest arm to the desired position. Now, I have some questions: How can I make the upper arm move alongwith the third so the end point of the arm reaches the desired point. Do I need to use the rotation matrices for both and if yes can someone give me some example or an help and is there any other possibl;e way to do this without rotation matrices??? The lowest arm only moves in one direction. I tried google it, they are saying that cross product of two vectors give the

I'm trying to devise an algorithm for a robot trying to find the flag(positioned at unknown location), which is located in a world containing obstacles. Robot's mission is to capture the flag and bring it to his home base(which represents his starting position). Robot, at each step, sees only a limited neighbourhood ( he does not know how the world looks in advance ), but he has an unlimited memory to store already visited cells. I'm looking for any suggestions about how to do this in an efficient manner. Especially the first part; namely getting to the flag. A simple Breadth First Search