Hello, I am configuring a hexacopter layout on a custom frame. The aircraft consists of a primary propulsion system (1, 2) and four ESC-controlled motors (3-6). Their positions are shown in the image below (image is for reference only).
It’s worth mentioning that the primary propulsion system generates the necessary thrust for hovering, while the four ESC-controlled propellers are used solely to stabilize the aircraft. In theory, the pitch of the aircraft should be controlled by the two primary propulsors. The roll and yaw of the aircraft should be stabilized by the ESC-controlled motors.
The first step was to stabilize the aircraft without the primary propulsion system. The ESC-controlled motors are tilted to provide some authority for yaw. This was necessary because the frame is heavy (70 kg), and when the ESC-controlled motors were positioned flat, they didn’t have enough torque to effectively rotate the aircraft around its yaw axis. As of right now, the PID values are tuned, and in stabilized mode, the system is stable across all three of its axes.
In the next step, I would like to integrate the primary propulsion system into the actuator geometry. The pitch should be controlled by the difference in RPM between the two propulsors. The biggest challenge is describing this system, as the force and moment directions are different compared to a typical propeller. As shown in the image above, the thrust vector from the primary propulsion system is pointed along the Z-axis, and the torque it generates rotates around the X-axis.
What would be the most convenient way to describe the variables like thrust and moment coefficients and the geometry of this system?