ROSSerial Integration

Thanks to a tip from Juan Miguel Jimeno - creator of CHAMP, I decided to forego custom Serial messaging in favor or ROSSerial. As a result, the Teensy firmware is cleaner, more compact, and more modular. Note that I am using ROSSerial for ROS Melodic, so follow the tutorial accordingly.

The Gait Planner (which can optionally run the RL agent) sends either joint angles or HipToFoot Vectors on the spot/joints topic, which is read by the Teensy. The Teensy publishes contact sensor and IMU data to spot/contact and spot/imu, which the RL agent can use as its state observations.

I also modified the servo_calibrator node. It will send your desired joint angle in degrees to the requested joint 0-11 and set all others to -999. The Teensy will recognize this invalid command and will not update the desired motor angle if it sees it. A how-to will be coming near the end of August.