
280 Nonlinear Optimal Control Theory
FIGURE 8.4
If |ψ
2
(t
0
)| ≤ λ
3
, the possible sequence of values assumed by u are
(a) {0} (c) {0, −1}
(b) {0, 1}
If λ
3
= 0, we immediately see from (8.9.8) that u takes values 1 or −1, except
at a single point which we can neglect. That is, the sequence of control values
assumed ar e
(a) {−1, 1}
(b) {1, −1}
When λ
3
= 0 the trajectory pattern and control synthesis could be deduced
from Fig. 8.4. Note that as λ
2
→ 0 the lines x
2
=
p
λ
1
/λ
2
and x
2
= −
p
λ
1
/λ
2
pass to infinity and the trajectory pattern g e ...