ATR3-b1: Framework

Although ATR3's entire chassis is made of thick metal that can be readily drilled for actuator mounting, I have opted for a framework-based design to better support vehicles with limited chassis attachment points.  For instance, most cars have sturdy attachment points below the driver's seat, whereas mounting directly to the plastic dashboard where the levers and buttons are located would be difficult.  Anton's framework is composed of 1/2" hollow square aluminum tubing, 1/16" thick wall...