The lateral-directional dynamics of the x-29 are stable.[^1] The roll rate is proportional to nonlinear stick deflection.[^1] The forward loop integrator on the roll-axis nulls any steady-state errors.[^1] The rate gyro inputs were processed through a notch filter and then a low-pass prefilter.[^1] The rudder pedals commanded a washed out stability axis yaw rate.[^1] The ailerons had priority over the symmetric flaperon deflections.[^1] There were 4 command feedback gains and 3 AOA breakpoints that were used as table lookups.[^1]
The forward-loop integrator would saturate and cause a pro-spin flaperon command, this was removed at high AOA.[^1] A high-gain roll damper suppressed wing rock near \(C_LMAX\). \(\dot{\beta}\) feedback helped to control the sideslip during high-AOA conditions.[^1] The vertical fin could experience buffets with an intensity of around 110g.[^1] A multi-rate gain lookup schedule was used as the AOA would change faster than the mach number.[^1] Notch filters were added as structural modes were making it through to the gyros.[^1] In the figure above, K2 and K27 are gains for the ARI interconnects and the roll rate-aileron.[^1] The latter was reduced to 0.48 deg/deg/sec to improve aircraft response.[^1] K13 is the lateral stick-aileron gain.[^1]
Source
- R. Clarke, J. J. Burken, J. T. Bosworth, and J. E. Bauer, “X-29 Flight Control System: Lessons Learned”.
Backlinks
Gain Scheduling
[[Low-Pass Filter]]
[[Notch Filter]]
[[Rate Saturation Equations]]
X-29 Flight Control System