Terminal Guidance and Control Techniques for Soft Lunar Landing

A decreased (compared to the no control system case) steady-state error to a s tep load torque is obtained b y making h large (or n ^> 1), as would be expected. The case for X = 0(A = B) need not be considered, because no gyroscopic effect is provided and there is no point in spinning the body. I n any event, the s teady-state errors for the spinning and nonspinning control system can be made comparable by the proper choice of k2, fe. I t should be noted t h a t the errors discussed in this section are measured to the principal axis. If another line in the body is to be stabilized, for instance an optical system whose sight line is tilted slightly from the principle axis, an addit ional wobble error results.