L = −kp sign(894)8q1:3 - ka (1±8q38q1:3) T L= -kp8q1:3-kaw (7.7) where kp and ka are positive scalar gains. Substituting Eq. (7.7) into Eq. (7.1b) gives the closed-loop system governed by Eq. (7.5) and i = -J¹ ([wx]Jw+kp8q1:3+kaw) The only equilibrium point is [8q3 ] = 0. (7.8) Stability is proven using Lyapunov's direct method. Reference [50] uses a difference between the actual and command quaternions in the definition of the candidate Lyapunov function. Here, a multiplicative approach is employed, which leads to the same result as in [50] but is more intuitive in terms of the quaternion error kinematics. Define the following candidate Lyapunov function: WTJw + kp8q38913+ ½ kp (1-894)² ≥ 0 (7.9) V = == Note that V0 when = 0 and 8q = = Iq, which is the equilibrium point. The time derivative of V is given by V = ½w³ Jw + kp8q|:38ġ1:3 − kp (1 − 894)8ġ4 (7.10) Substituting Eqs. (7.6) and (7.8) into Eq. (7.10) gives V == = - ———½ (w² ‍8q1:3) [kp + kp8q4 − k p(1 + 894)] — —½±ka ww 0 - (7.11) Thus, the closed-loop system is stable since V ≤0. Asymptotic stability can be proven using LaSalle's theorem (see Sect. 12.2.2). The equality in Eq. (7.11) is given when = 0, where 8q1:3 can be anything. We must check that the system cannot remain in a state where V = 0 while 8q1:30. Equation (7.11) guarantees that lim, ∞ = 0. The closed-loop dynamics in Eq. (7.8) shows that this asymptotic condition can only be achieved

Elements Of Electromagnetics
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Author:Sadiku, Matthew N. O.
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The control law in Eqn. 7.7 has the candidate Lyapunov function as Eqn. 7.9. What would be the Lyapunov function for control law equation in the second image?

L = −kp sign(894)8q1:3 - ka (1±8q38q1:3)
T
Transcribed Image Text:L = −kp sign(894)8q1:3 - ka (1±8q38q1:3) T
L= -kp8q1:3-kaw
(7.7)
where kp and ka are positive scalar gains. Substituting Eq. (7.7) into Eq. (7.1b) gives
the closed-loop system governed by Eq. (7.5) and
i = -J¹ ([wx]Jw+kp8q1:3+kaw)
The only equilibrium point is [8q3 ] = 0.
(7.8)
Stability is proven using Lyapunov's direct method. Reference [50] uses a
difference between the actual and command quaternions in the definition of the
candidate Lyapunov function. Here, a multiplicative approach is employed, which
leads to the same result as in [50] but is more intuitive in terms of the quaternion
error kinematics. Define the following candidate Lyapunov function:
WTJw +
kp8q38913+ ½ kp (1-894)² ≥ 0 (7.9)
V = ==
Note that V0 when
= 0 and 8q
=
=
Iq, which is the equilibrium point. The
time derivative of V is given by
V = ½w³ Jw + kp8q|:38ġ1:3 − kp (1 − 894)8ġ4
(7.10)
Substituting Eqs. (7.6) and (7.8) into Eq. (7.10) gives
V
==
=
-
———½ (w² ‍8q1:3) [kp + kp8q4 − k p(1 + 894)] — —½±ka ww
0
-
(7.11)
Thus, the closed-loop system is stable since V ≤0.
Asymptotic stability can be proven using LaSalle's theorem (see Sect. 12.2.2).
The equality in Eq. (7.11) is given when = 0, where 8q1:3 can be anything.
We must check that the system cannot remain in a state where V = 0 while
8q1:30. Equation (7.11) guarantees that lim, ∞ = 0. The closed-loop
dynamics in Eq. (7.8) shows that this asymptotic condition can only be achieved
Transcribed Image Text:L= -kp8q1:3-kaw (7.7) where kp and ka are positive scalar gains. Substituting Eq. (7.7) into Eq. (7.1b) gives the closed-loop system governed by Eq. (7.5) and i = -J¹ ([wx]Jw+kp8q1:3+kaw) The only equilibrium point is [8q3 ] = 0. (7.8) Stability is proven using Lyapunov's direct method. Reference [50] uses a difference between the actual and command quaternions in the definition of the candidate Lyapunov function. Here, a multiplicative approach is employed, which leads to the same result as in [50] but is more intuitive in terms of the quaternion error kinematics. Define the following candidate Lyapunov function: WTJw + kp8q38913+ ½ kp (1-894)² ≥ 0 (7.9) V = == Note that V0 when = 0 and 8q = = Iq, which is the equilibrium point. The time derivative of V is given by V = ½w³ Jw + kp8q|:38ġ1:3 − kp (1 − 894)8ġ4 (7.10) Substituting Eqs. (7.6) and (7.8) into Eq. (7.10) gives V == = - ———½ (w² ‍8q1:3) [kp + kp8q4 − k p(1 + 894)] — —½±ka ww 0 - (7.11) Thus, the closed-loop system is stable since V ≤0. Asymptotic stability can be proven using LaSalle's theorem (see Sect. 12.2.2). The equality in Eq. (7.11) is given when = 0, where 8q1:3 can be anything. We must check that the system cannot remain in a state where V = 0 while 8q1:30. Equation (7.11) guarantees that lim, ∞ = 0. The closed-loop dynamics in Eq. (7.8) shows that this asymptotic condition can only be achieved
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