On the master branch, commanding a positive steering angle makes the car turn right, and a negative steering angle makes the car turn left.

By the right-hand rule, the yaw angle increases counterclockwise, so both the command input and sensor reading output need to have their sign swapped.

Individual wheels have sign reversed, i.e. commanding the right wheel a velocity of 1 m/s will result in a velocity of -1 m/s.

After Peter added the filter cap the readings have been a lot smoother. But it's been months since we last calibrated it. I want to know if the limited steering range is the result of the calibration being off, or the new shield we're using.

Tasks

• modify Arduino code to read potentiometer values here in dcservo.cpp
• collect pot readings with front wheels turned far left, far right, and straight ahead
• comment out calibration line and commit updated values

The current kilotron branch encoder code is just a copy of the master (Gigatron) branch. We are getting readings from the encoders, but the number of ticks per revolution is probably different, so we need to test how the resulting odometry compares to reality.

Odometry Test

1. Measure out a fixed length of several meters in a straight line and mark the start and end points
2. Place Kilotron at the start and launch gigatron_hardware/launch/kilotron.launch
3. Rosbag record all topics
4. Drive Kilotron to the end of the line and stop the car, and the rosbag
5. Compare the values on the odom topic to the actual length traveled

Tasks

• Perform the above test
  • Bonus Points: Repeat the test in reverse
• change the PULSES_PER_REV value in kilotron branch if necessary

Tasks

• update master branch with new messages
• update kilotron branch with new messages

Right now the JetsonCommander class only handles motor RPM commands 0 or greater.

The current behavior is to switch to RC throttle (and keep autonomous steering) which will result in coasting. Instead the Arduino should issue closed-loop zero velocity commands, so the car will actually stop.

Tasks

• update code
  • master branch
  • kilotron branch
• estop in semiautomatic mode
  • master branch
  • kilotron branch
• test on car
  • Kilotron
  • Gigatron

The current Arduino code is hardcoded to have the car running either in fully autonomous mode, or semiautomatic mode (autonomous steering with RC throttle).

Instead, add a callback method to gigabug.ino that will set the mode to either autonomous or semiautomatic.

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The relevant variable is _autonomous in JetsonCommander (see usage in context.cpp

Probably have it light up when it's autonomous/semiautomatic (i.e. _autonomous > 0).

Check if the output of a zero steering angle command from ROS in autonomous mode results in a zero steering angle on the vehicle.

Check if the output of a positive steering angle command from ROS results in steering left, and a negative steering angle command results in steering right.

Test Procedure

Note: this test can only be performed after metatron issue #5 is successfully resolved

• Pull and upload latest code on kilobug branch to Kilotron Arduino
• Launch Arduino code: roslaunch gigatron_hardware kilotron.launch
• Use keyboard to control steering: rosrun gigatron hare
• Comment here with test results

Relevant topics:

/command/drive with desired steering angle and wheel velocities
/arduino/command/motors with desired steering pwm

The right rear wheel consistently gives higher readings for distance traveled. Adjust PULSES_PER_REV on a per-wheel basis if needed.

Tasks

• set up voltage monitoring hardware
• publish ROS message with battery voltage
• calibrate readings

Right now, RC mode has both rear wheels driven equally. Instead, we can modify the motor commands based on the RC steering angle.

This enables us to test the car's native velocity control safely. Issuing closed-loop stop commands when the throttle is released is a better safety mechanism than switching to RC mode, where the vehicle can coast.