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A comparison is made between constrained, two-dimensional, reentry reference trajectories generated by genetic and sequential quadratic programming methods. The objective is to generate a reentry trajectory with minimum control while satisfying constraints on dynamic pressure, heating, lifting, final velocity and altitude. It is shown that the genetic programming method discovered much smoother trajectories that easily satisfy all constraints.

In this paper fundamental analytical results for automobile lateral stability are developed. Specifically, the linear two degree-of-freedom, fixed steering control, front wheel steer and four wheel steer automobiles with a time lagged lateral tire force model is employed in the analysis. The stability conditions are derived using Routh Hurwitz criterion and Lyapunov’s method. The results are mainly algebraic in nature and examples are given demonstrating potential problems of front wheel and four wheel steering vehicles due to the time lag in the tire’s lateral force.

This paper deals with estimating the lateral stability region of a nonlinear 2 DOF vehicle via Lyapunov Second Method and the non-Lyapunov methods of tangency points and trajectory reversal. The nonlinearity of the model is incorporated in an analytical expression for the lateral tire force. It is shown that the derived analytical expressions for equilibrium points defines the outer limits of the stability region.