A new pulse modulator for solid propellant attitude control motors

Antimissile interceptors with the attitude control motors (ACM) were researched. For solid propellant ACM, a pulse frequency modulation scheme is proposed, which is based on conventional PWPF modulator. The modulator extends the application of modulation control method to solid propellant ACM, and integrates it with a feedback of thrust estimation which is decided by location and thrust interaction factors. The stability of the new modulator was analyzed by Lyapunov method and a stability margin was given. Simulations show that the stability margin is conservative, but acceptable. Interceptor simulations using the modulator indicate that this technique provides closer-to-linear actuation than conventional bang-bang thruster control methods.