Applied Mathematics
Vol. 3 No. 1 (2012) , Article ID: 16767 , 6 pages DOI:10.4236/am.2012.31007
Some Kinds of Sheaf Control Problems for Control Systems
Faculty of Mathematics and Computer Science, Vietnam National University, Ho Chi Minh City, Vietnam
Email: *ndphu_dhtn@yahoo.com.vn
Received November 8, 2011; revised December 20, 2011; accepted December 27, 2011
Keywords: Control Systems; Sheaf Solutions; Control Theory
ABSTRACT
Recently, the field of differential equations has been studying in a very abstract method. Instead of considering the behaviour of one solution of a differential equation, one studies its sheaf-solutions in many kinds of properties, for example, the problems of existence, comparison, … of sheaf solutions. In this paper we study some of the problems of controllability for sheaf solutions of control systems.
1. Introduction
In [1-4] the authors have investigated sheaf solutions of control differential equations in the fields: comparison of sheaf solutions in the cases’ two admissible controls and
, and some initial conditions
,
, where the Hausdorff distance between the sets of initials
and
is enough small.
The problems of sheaf controllability and sheaf optimization are still open. The present paper is organized as follows. In Section 2, we review some facts about sheaf solutions. In Section 3 we give many kinds of sheaf control problems, of sheaf controllability optimal problems.
2. Preliminaries
In n-dimension Euclidian space usually we have considered the control systems (CS):
(2.1)
where,
. A solution to CS (2.1) is represented by:
(2.2)
,
,
is a collection of some given initials.
Definition 2.1. We say that a control is admissible, if:
1) satisfies (2.2) for all
;
2) is bounded by norm
.
That means the functions are measurable (integrable) satisfiying almost everywhere on
the relationships (2.1) and (2.2), then
is called the trajectory of the CS (2.1) and
is called the control. Therefore, we shall always understand a pair of functions
interrelated by the relationship (2.1) and (2.2). It is clear that several controls
can correspond to one
trajectory and if CS (2.1) has a nonunique solution, then several trajectory
can correspond to one control
.
Definition 2.2. A state pair of solutions of control systems (2.1) will be a controllable if after time
we shall find a control
such that:
(2.3)
Definition 2.3. A control system (2.1) is said to be:
(GC) global controllable if every state pair of set solution.
(GA) global achievable if for every we have a state pair of solutions
that is GC.
(GAZ) global achievable to zero if for every we have a state pair
that will be controlable.
In [2] the authors have compared the sheaf solutions for set control differential equations (SCDEs).
In [4] the author has study the problems (GC), (GA) and (GAZ) for set control differential equations (SCDEs).
Definition 2.4. A sheaf solution (or sheaf trajectory) is denoted by a number of solutions that make into sheaves (lung one on top of the other and often tied together) for all
:
(2.4)
Definition 2.5. A cut-set (a cross-area) of sheaf solution at time
is denoted by:
(2.5)
3. Main Results
Let’s consider again the control systems (CS):
(3.1)
where,
, Q is a compact set in
and
—admissible controls. Assume that for CS (3.1) there exists solution (2.2) and sheaf solution (2.4).
We will need the following hypotheses on the data of control problem for CS (3.1):
(Hf1):
(Hf2):
where.
Assume that at all,
for two admissible controls
we have two forms of sheaf solutions:
(3.2)
where—solution of CS (2.1) (see Figure 1).
Figure 1. The sheaf solutions of CS (2.1) in two admissible controls.
Definition 3.1. The Hausdorff distance between set and
is denoted by:
Definition 3.2. The pair of the any sets will be controllable if after time
we shall find a control
and one map
such that:
(3.3)
Theorem 3.1. Under Hypothes (Hf1), let —is initial, any set
. The pair of the sets
will be controllable if:
1) belongs to solutions of CS (3.1), and 2)
is cut-set of sheaf solution to (3.1), that means
.
Proof. If belongs to solutions of CS(3.1) then it is
.
For any we have a pair
that is controllable, because
, where
—cut-set of sheaf solutions with
As in results, we have one map moving to
that means
.
Definition 3.3. The control system (3.1) is said to be:
(SC1) sheaf controllable in type 1, if for all, there exists
and admissible controls
that satisfy
then
(3.4)
(SC2) sheaf controllable in type 2 for any admissible control, if for all
, there exists
such that the initials
with
then
(3.5)
(SC3) sheaf controllable in type 3, if for all, there exist
,
such that the initials
with
and for any admissible controls
that satisfy
then
(3.6)
Lemma 3.1. Under Hypothes (Hf1), for all, there exists
if control system (3.1) with:
then two cut -sets of sheaf-solutions of CS (3.1) satisfy an estimate:
(3.7)
Proof. Suppose that for CS (3.1) the right hand side satisfies (Hf1) then there exists unique solution
which satisfies (2.2).
If—sheaf solution of CS (3.1) then for admissible control
we have the cut-sets at any times
, that satisfy estimate (3.7):
and
.
We have
Theorem 3.2. Assume that, under Hypothes (Hf2), the admissible controls that satisfy
, then CS (3.1) is sheaf-controllable SC1.
Proof. Suppose that for CS (3.1) the right hand side satisfies (Hf2) then there exists unique solution
which satisfies (2.2).
If—sheaf solution of CS (3.1) then for admissible control
we have the cut-sets at every times
, that satisfy estimate (3.7):
and
.
We have
as results the CS (3.1) is sheaf-controllable SC1.
Corollary 3.1. If CS (3.1) is SC1, the right hand side satisfies condition of lemma 3.1 then for all
there exists
such that:
Proof. Because solution of CS (3.1) is equivalent: then
by lemma 3.1 we have:
Theorem 3.3. Under hypothes (Hf1), assume that the initials for all
, there exists
such that:
then for any admissible control
we have:
that means CS (3.1) is sheaf controllable CS2.
Proof. We have estimate
For all,
such that
and
choosing
then we have
. As results imply that CS (3.1) is SC2.
Theorem 3.4. Under Hypothes (Hf2), assume that for all and satisfy the followings:
1)
2)then for any admissible controls
we have:
that means CS (3.1) is sheaf controllable CS3.
Proof. Beside (2.4) for and
we have:
and estimate as following:
Choosing, we have:
Definition 3.4. We say that for control system (3.1) are given OCP—the optimization control problem if it denotes:
(3.8)
where, such that V(T,x) is solution to Hamillton Jacobi Bellman (HJB)—partial differential equation:
(3.9)
We have to find the optimal control for OCP (3.8).
Lemma 3.1. In optimization control problems (3.8) if then
Proof. Putting
we have integral for all:
Because
impilies that
Theorem 3.5. Assume that OCP (3.8) has and there exists feedback
such that:
then exists optimal control for OCP (3.8).
Proof. Assume that—one of solutions of control systems (3.1) such that
there exists feedback
:
By lemma 3.3 we have
such that—optimal control for OCP (3.8).
Definition 3.5. We say that for control system (3.1) are given SOCP—the sheaf-optimization control problem if it denotes:
(3.10)
where—integral on
and
such that
is solution to (HJB)—partial differential equation:
(3.11)
Lemma 3.2. Assume that V(t, x) is a solution of HJB partial differential equation (3.10) with the boundary conditions:
If function
and u(t) is admissible control then for optimization control problem SOCP (3.10) there exists estimate:
Proof. Putting
we have:
where
then
By (*) we have
and then (**) impilies that
Theorem 3.6. (Necessary Conditions)
Assume that SOCP (3.10) has solution, that means there exists optimal control such that
and
is a solution of HJBpartial differential equation (3.11) then the necessary conditions for this SOCP (3.10) are:
1)
2), where
Proof. Suppose that a function SOCP (3.10) that means
. Because V(t, x)-solution of HJBpartial differential equation (3.11):
withif function
satisfies:
that integrable on sheaf solutions.
By lemma 3.2, if is admissible control then for optimization control problem SOCP (3.10) there exists estimate:
Assume that for SOCP (3.10) has optimal control then for all
, we have
Theorem 3.7. (Sufficient Conditions)
Assume that any admissible control for SOCP (3.10) and
is a solution of HJB-partial differential Equation (3.11) then the sufficient conditions for this SOCP (3.10) are:
1)
2)
3) there exists such that
Proof. There exists the other admissible control, such that for SOCP (3.10) we have
By condition (1) of theorem 3.6 we have a function
that integrable on sheaf solutions.
We find the function from equation:
with condition.
By condition (2) of this theorem:
and implies that—optimal control for SOCP (3.10).
Example 3.1. When using missiles not for the purpose of shooting down aircraft noise bomb attack as B52 shot if only 01 or 02 rockets can not succeed. The rockets theit fire it will be the interference or escort aircraft will be explosive.
A problem arises: What to do in order to shoot down aircraft noise when operating in the sky. To solve this problem, we must fire simultaneously from SAM sites from 03 or more results. The rockets have to be controlled from headquarters and shot to pick the exact point-B52.
Mathematical model for problem shooting attack aircraft noise control system with (3.10), the test bundle (2.4) and optimization problem are (SOCP) in the above with n = 3 (see Figure 2).
4. Conclusions
The Sheaf Optimization problem for Control Systems
Figure 2. The sheaf of SAM shooting down aircraft noise bomb attack as B52.
(SOPCS) have a high practical significance, as the series of SAM to destroy B52 attack aircraft with fighter jamming, or laser beam to destroy targets, like the beams in materials research of Physical nuclear, etc, … This paper described some types of sheaf optimal problems. We can solve them by Pontryagin’s Principle, Lyapunov’s Energy Function or by the Hamilton’s Principle. In this paper we present the necessary and sufficient conditions for this problem by Hamilton’s Principle, namely by HJB equations.
In the near future, we will set the numerical calculations can be applied to a clearer and will study the different Optimization problems with some controls.
5. Acknowledgements
The authors gratefully acknowledge the referees for their careful reading and many valuable remarks which improved the presentation of the paper.
REFERENCES
- A. D. Ovsyannikov, “Mathematical methods in sheaf controls,” Leningrad University Pub., Saint Petersburg, 1980.
- N. D. Phu and T. T. Tung, “Some properties of sheafsolutions of sheaf fuzzy control Problems,” Electronic Journal of Differential Equations, Vol. 2006, No. 108, 2006, pp. 1-8.
- N. D. Phu and T. T. Tung, “Some results on sheaf solutions of sheaf set control differential equations,” Journal of Nonlinear Analysis: Theory, Methods & Applications, Vol. 67, No. 5, 2007, pp. 1309-1315. doi:10.1016/j.na.2006.07.018
- N. D. Phu, “On the Global Controllable for Set Control Differential Equations,” International Journal of Evolution Equations, Vol. 4, No. 3, 2009, pp. 281-292.
NOTES
*Corresponding author.