This question was asked inGPSC Deputy Executive Engineer (Electrical) Paper 2024Question 10 of 33 published · Gujarat Public Service CommissionOpen paper
Q11ModerateState-Space Analysis

निम्नलिखित कथन पढ़िए:
कथन 1: यदि नियंत्रण सदिश u(t) द्वारा निर्दिष्ट परिमित समय में सिस्टम अवस्था को प्रारंभिक अवस्था X(t_0) से किसी भी वांछित अवस्था X(t) तक ले जाना संभव हो, तो सिस्टम पूर्णतः नियंत्रणीय (controllable) कहलाता है।
कथन 2: यदि समय अंतराल 0 ≤ t ≤ ∞ में आउटपुट y(t) के मापन से प्रत्येक अवस्था X(t_0) को पूर्णतः पहचाना जा सके, तो सिस्टम पूर्णतः प्रेक्षणीय (observable) कहलाता है।
निम्नलिखित में से सही विकल्प चुनिए:

उत्तर और चरणबद्ध हल
सही उत्तर: A. कथन 1 और कथन 2 दोनों सही हैं।
संक्षिप्त व्याख्या

कथन 1 पूर्ण नियंत्रणीयता का मानक अर्थ है: इनपुट परिमित समय में अवस्था को किसी भी वांछित अवस्था तक ले जा सकता है। कथन 2 प्रेक्षणीयता का विचार है: आउटपुट मापन से प्रारंभिक अवस्था पुनः प्राप्त की जा सकती है। n-अवस्था LTI मॉडल के लिए rank(𝒞)=n और rank(𝒪)=n। अतः विकल्प A।

विस्तृत हल (मूल भाषा में)

What This Question Is Really Testing

State variables represent the internal condition of a dynamic system. Controllability asks whether the input can move that internal state where we want it. Observability asks whether output measurements contain enough information to determine the internal state.

Concept Foundation

For the LTI state model ẋ = Ax + Bu, y = Cx + Du, the two standard matrix tests are:

𝒞 = [ B AB A²B … A^n−1B ]

𝒪 = [ C ; CA ; CA² ; … ; CA^n−1 ]

Step 1 — Evaluate Statement 1: Controllability

The statement says that a suitable control input can transfer the system from an initial state to any desired state in a specified finite time. That is the defining idea of complete controllability .

rank(𝒞) = n ⇒ completely controllable

Step 2 — Evaluate Statement 2: Observability

The statement says that the state can be completely identified from measured outputs over the observation interval. That is the defining idea of complete observability .

rank(𝒪) = n ⇒ completely observable

Step 3 — Select the Statement Combination

Both definitions express the intended properties correctly, so the correct option is A .

Why This Method Works

The direction of information/action distinguishes the concepts: controllability is input → state ; observability is state → measured output .

Independent Verification / Cross-Check

If A, B and C matrices were supplied, the rank tests above would provide an independent algebraic verification. Here the item asks only about the definitions.

Concept Extension

  • A mode can be uncontrollable even if it appears in the state equations.
  • A mode can be unobservable even though it affects internal state dynamics.
  • Minimal realizations are both controllable and observable.

Exam Strategy

Use the mnemonic: Can I command the state? → controllability. Can I see/reconstruct the state? → observability.

Quick Trick

Command it = controllability; see it = observability.

Why Other Options Are Wrong

B and C reject one correct definition; D rejects both. Only A accepts the two intended definitions together.

Common Mistake

Interchanging the matrix tests: B generates the controllability matrix, while C generates the observability matrix.

Solution diagram – निम्नलिखित कथन पढ़िए: कथन 1: यदि नियंत्रण सदिश u(t) द्वारा निर्दिष्ट परिमित…
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