Monday, 20 January 2014

Robbie Navagation Test Smach

Running with the action server was one goal but using ROS smach and the ability
to use multiple goals  or way points to get to the target was always the plan
in the attached video shows Robbie moving in a triangle to achieve a target.
Next we are going to add arm actions to the routine

Friday, 17 January 2014

Autonomous Navigation

Robbie's first autonomous  navigation run the goal is navigate through a door
in this run the door is 110cm wide but getting through was quit hard. A lot more work
will be required adjusting the parameters. Robbie has a habit of spinning in place trying
to find a solution. The cost map and size of the robot have a large bearing on behavior

Here is a picture of Robbie in Rviz showing the gap after the infatuation of the cost map 

when there is no clear path through,  the robot will spin in place to find a clear path.
now the fun starts learning to drive  by setting nav goals

Thursday, 16 January 2014

Robbie the cartographer

Finally received the new encoder disc's after fitting them the problem of erratic
reading changed side after 3 days of work the encoder are running well. The main cause was the disc was not aligned and running true, the axles are only threaded rod
which gives a little movement i put a layer of tape around the rod and every thing started to work as expected.  That doesn’t mean there are no more problems, after adjusting the encoder counts Robbie was again running straight  but long for a 1 meter move he went 1.16 and for every turn he over shot by 22 degrees. Once i examined the data the distance travelled in real life matched the distance and angles
in his localization, the extra distance came from deceleration when i have a spare day I will adjust the PID loop to be more responsive.  The deceleration issuse will not impact navigation to much so the first task was to make a map.  To my surprise the maps were the best best we have ever achieved they still need a lot of work for them to be perfect (we are using a kinect not a laser scanner) before we can do long range navigation. Robbie was able to navigate in the garage with out crashing into the walls the localization on the map was good. Over the next couple of days I want to run more navigation test and a few videos I want to see how he goes up the ramp and through the doors. I will need to work out a good position for the arms just hanging down is not good the hand can get caught on object.