New near-optimal feedback guidance algorithms for space missions

“Flyable” Guidance and Control Algorithms for Orbital Rendezvous Maneuver

“…The idea is to modify the classical ZEM/ZEV (as in [23], [24] and in Section 4.2), starting from an ideal trajectory and considering the ideal positions and velocities as final parameters. The goal is to avoid high acceleration commands.…”

“…ZEM/ZEV optimal feedback guidance laws are usually used for asteroid intercept and rendezvous missions, through the definition of an acceleration command related to terminal velocity direction or magnitude requirements, when the gravitational field could be assumed as an explicit function of time [23], [24].…”

“…In general, the control gain K in (23) must guarantee that the sliding motion on the desired sliding manifold is reached and maintained. The sliding output σ x , which is the switching function in the controller (23), is For the tracking control problem of the attitude of the chaser a second order sliding mode (2-sliding mode) algorithm, known as super-twisting (STW) [53], is analyzed in [41]. The STW algorithm designs a continuous control law, which steers to zero in finite time both the sliding output and its first time derivative, in the presence of smooth matched disturbances with bounded gradient for which a bound is assumed to be known.…”

New Hypervelocity Terminal Intercept Guidance Systems for Deflecting/Disrupting Hazardous Asteroids

“…Previous research work of Hawkins [16,17] has explored the use of various proportional navigation (PN) guidance logic and predictive guidance schemes. Furthermore, he investigated the intercept capability of each guidance law separately.…”

“…Doing so may have the outcome of reducing the required fuel usage while still maintaining the desired precision. The research work of Hawkins [16,17], which is based on ideal image optics, were later implemented on Graphical Processing Units (GPUs) in Kaplinger [18].…”