Helicopter translational rate command using individual channel analysis and design

Translational rate command (TRC) involves controlling the Earth referenced forward and side velocities using the helicopter´s cyclic control. Handling qualities requirements for TRC systems suggest that the design should comprise an inner attitude command-attitude hold (ACAH) loop with TRC control as an outer loop. This forms a non-square system, and a method to determine the effects of this system on stability robustness is proposed. Control synthesis was performed using the method of individual channel analysis and design. This technique is a neoclassical, frequency domain control analysis and design method for multivariable systems. The control law obtained is very simple and the time responses, simulated using the nonlinear helicopter model HELISIM, are found to meet Level 1 requirements.