Fig 10. Free-body diagram of a quad-thruster in a side view to demonstrate the pitch/roll control.

The pitch/roll control of a quad thruster is similar to multicopters. Thrust generated by i-th thruster is denoted by F_i. For positive pitch/roll angle, θ. F₁+F₃ and F₂+F₄ can be controlled actively to stabilize the thruster at a desired orientation θ.