Previously, we wrote about DiscoFish’s autonomous driving capabilities. Once autonomous driving was up and running we decided to also implement drive-by-wire, so that a person could also drive the Fish by remote control from the top level or outside. You know, just keeping the options open.
The drive-by-wire design uses a Spektrum DX7s 2.4GHz transmitter and an AR8000 8-Channel DSMX receiver. The control panel has switches to select driving modes, as shown below.
Driving control switches, and controller box stowed safely under the seat
The ignition and gear shift were left under human control as a safety precaution, so under autonomous or RC control DiscoFish only drives forward. The driver can manually override the RC or autonomous driving at any time, and there is also a big red Emergency Stop button to turn off all the control motors.
When drive-by-wire mode is selected, communication with the Parallax Servo Controller is cut off (see the autonomous block diagram), disabling autonomous mode. The RC receiver directly controls the brake motor, gas motor, and steering motor controller. The steering motor requires a motor controller because it has more intelligence; a quadrature encoder monitors the position of the sheering wheel.
Here you can see the motors and motor controller for the gas, brake, and steering.
And here is Nuvation CEO Michael Worry demonstrating how the RC controller works (dressed in disco attire for the full effect.)
Next up, flamethrower design! Stay tuned.