Phidgets Motor Encoder

References

• Four Port Encoder Phidgets Guide This one didn't work because ROS wants a serial number of each port. This one has a single serial number for all ports.
• Single Port Encoder Phidget Guide There are two of these.
• ROS Phidgets Documentation
• Testing on Mac

Check

 rosrun phidgets manager
   |-   # -|-              Type              -|- Serial No. -|-  Version -|
   |-------|----------------------------------|--------------|------------|
   |-   0 -|-                 PhidgetEncoder -|-     351673 -|-      302 -|
   |-------|----------------------------------|--------------|------------|
   |-   1 -|-            PhidgetInterfaceKit -|-      69535 -|-      825 -|
   |-------|----------------------------------|--------------|------------|
   |-   2 -|-            PhidgetMotorControl -|-     147489 -|-      102 -|
   |-------|----------------------------------|--------------|------------|
   |-   3 -|-                 PhidgetEncoder -|-     351547 -|-      302 -|
   |-------|----------------------------------|--------------|------------|

Modified the serial numbers for the left and right encoders in the odometry.launch file in the ..../floor_hugger/launch directory.

 diff odometry.launch.org odometry.launch
   15c15
   <         <param name="serial" value="52980" />
   ---
   >         <param name="serial" value="351547" />
   19c19
   <         <param name="serial" value="54104" />
   ---
   >         <param name="serial" value="351673" />
   24,25c24,25
   <         <param name="serialleft" value="52980" />
   <         <param name="serialright" value="54104" />
   ---
   >         <param name="serialleft" value="351547" />
   >         <param name="serialright" value="351673" />

Execute

Terminal 1

 roscore

Terminal 2

 roslaunch floor_hugger odometry.launch
   ... logging to /home/eepp/.ros/log/184aed3a-ee5e-11e5-86af-7c5cf84b92a4/roslaunch-hood-4875.log
   Checking log directory for disk usage. This may take awhile.
   Press Ctrl-C to interrupt
   Done checking log file disk usage. Usage is <1GB.
   
   started roslaunch server http://hood:48802/

   SUMMARY
   ========

   PARAMETERS
    * /encoder_left/serial: 351547
    * /encoder_right/serial: 351673
    * /odometry/countspermmleft: 100
    * /odometry/countspermmright: 100
    * /odometry/serialleft: 351547
    * /odometry/serialright: 351673
    * /odometry/verbose: True
    * /odometry/wheelbase: 400
    * /rosdistro: indigo
    * /rosversion: 1.11.16
 
   NODES
     /
       encoder_left (phidgets/high_speed_encoder)
       encoder_right (phidgets/high_speed_encoder)
       odometry (phidgets/odometry)
 
   ROS_MASTER_URI=http://hood:11311

   core service [/rosout] found
   process[encoder_left-1]: started with pid [4893]
   process[encoder_right-2]: started with pid [4894]
   process[odometry-3]: started with pid [4910]
   [ INFO] [1458453025.200790426]: Left encoder: phidgets/encoder/351547
   [ INFO] [1458453025.205863972]: Right encoder: phidgets/encoder/351673

Terminal 3

This example shows the topic echo while one motor is running. The "pose" section displays the current position. The "twist" section displays the change in position impacted by the twist of the robot.

 rostopic echo odom
   ---
   header: 
     seq: 35304
     stamp: 
       secs: 1458454629
       nsecs: 943339159
     frame_id: odom
   child_frame_id: base_link
   pose: 
     pose: 
       position: 
         x: -0.300059982299
         y: 0.565528418531
         z: 0.0
       orientation: 
         x: -0.0
         y: 0.0
         z: 0.151113732152
         w: -0.988516383251
     covariance: [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
   twist: 
     twist: 
       linear: 
         x: 0.0177976840035
         y: -0.00553014091365
         z: 0.0
       angular: 
         x: 0.0
         y: 0.0
         z: -0.093185371335
     covariance: [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
   ---