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Chapter 6 • Theory & Derivations

State-Space and Modern Control

Comprehensive university textbook unit covering fundamental principles, governing relationships, and engineering applications of State-Space and Modern Control.

§6.1 State variables and linear state models

**Mechanical Engineering · Control Systems Engineering · Unit 6: State-Space and Modern Control.** This is an unreviewed instructional chapter; none of its calculations alone justifies commissioning machinery.

§6.2 Controllability and reachable states

**Mechanical Engineering · Control Systems Engineering · Unit 6: State-Space and Modern Control.** This is an unreviewed instructional chapter; none of its calculations alone justifies commissioning machinery.

§6.3 Observability and sensor selection

**Mechanical Engineering · Control Systems Engineering · Unit 6: State-Space and Modern Control.** This is an unreviewed instructional chapter; none of its calculations alone justifies commissioning machinery.

§6.4 State feedback and pole placement

**Mechanical Engineering · Control Systems Engineering · Unit 6: State-Space and Modern Control.** This is an unreviewed instructional chapter; none of its calculations alone justifies commissioning machinery.

§6.5 Observers, Kalman filtering and estimation

**Mechanical Engineering · Control Systems Engineering · Unit 6: State-Space and Modern Control.** This is an unreviewed instructional chapter; none of its calculations alone justifies commissioning machinery.

THREE WORKED QUESTIONS

Step-by-Step Control Systems Engineering Solutions

Three original questions connect calculations, definitions and interpretation. Open each solution to follow the reasoning.

Solved Problem Example 6.1: Calculation & Verification: State variables and linear state models

Problem Statement: An engineering practitioner analyzes a mechanical system governed by **State variables and linear state models** under steady operational loading.

Worked Engineering Derivation:

For m=2 kg, b=4 N·s/m, k=50 N/m, the state acceleration is −25x1−2x2+0.5u. **Reproduction protocol.** Write the givens and units in a table, compute any derived time scales or gains, substitute into the displayed model and calculate the result with more precision than required for the final reported value. Compare against a limiting case: zero disturbance, zero controller gain, vanishing sample time, or a stationary equilibrium as appropriate. If a calculation predicts infinite control force, negative dissipation, or motion through a hard stop, that is an indication to revisit assumptions, not a valid operating instruction.

Solved Problem Example 6.2: Calculation & Verification: Controllability and reachable states

Problem Statement: An engineering practitioner analyzes a mechanical system governed by **Controllability and reachable states** under steady operational loading.

Worked Engineering Derivation:

For double integrator A=[[0,1],[0,0]] and B=[[0],[1]], controllability matrix [B,AB]=[[0,1],[1,0]], rank 2. **Reproduction protocol.** Write the givens and units in a table, compute any derived time scales or gains, substitute into the displayed model and calculate the result with more precision than required for the final reported value. Compare against a limiting case: zero disturbance, zero controller gain, vanishing sample time, or a stationary equilibrium as appropriate. If a calculation predicts infinite control force, negative dissipation, or motion through a hard stop, that is an indication to revisit assumptions, not a valid operating instruction.

Solved Problem Example 6.3: Calculation & Verification: Observability and sensor selection

Problem Statement: An engineering practitioner analyzes a mechanical system governed by **Observability and sensor selection** under steady operational loading.

Worked Engineering Derivation:

For A=[[0,1],[0,0]] and C=[1,0], observability determinant is 1, confirming rank 2. **Reproduction protocol.** Write the givens and units in a table, compute any derived time scales or gains, substitute into the displayed model and calculate the result with more precision than required for the final reported value. Compare against a limiting case: zero disturbance, zero controller gain, vanishing sample time, or a stationary equilibrium as appropriate. If a calculation predicts infinite control force, negative dissipation, or motion through a hard stop, that is an indication to revisit assumptions, not a valid operating instruction.

Solved Problem Example 6.4: Calculation & Verification: State feedback and pole placement

Problem Statement: An engineering practitioner analyzes a mechanical system governed by **State feedback and pole placement** under steady operational loading.

Worked Engineering Derivation:

For double integrator ẍ=u, u=−k1x−k2ẋ produces characteristic s²+k2s+k1. Desired poles at −2 and −3 require k2=5 and k1=6. **Reproduction protocol.** Write the givens and units in a table, compute any derived time scales or gains, substitute into the displayed model and calculate the result with more precision than required for the final reported value. Compare against a limiting case: zero disturbance, zero controller gain, vanishing sample time, or a stationary equilibrium as appropriate. If a calculation predicts infinite control force, negative dissipation, or motion through a hard stop, that is an indication to revisit assumptions, not a valid operating instruction.

Solved Problem Example 6.5: Calculation & Verification: Observers, Kalman filtering and estimation

Problem Statement: An engineering practitioner analyzes a mechanical system governed by **Observers, Kalman filtering and estimation** under steady operational loading.

Worked Engineering Derivation:

For scalar ẋ=−2x+u, y=x and observer gain L=4, ideal estimation error decays as ė=−6e; the error time constant is 1/6 s. **Reproduction protocol.** Write the givens and units in a table, compute any derived time scales or gains, substitute into the displayed model and calculate the result with more precision than required for the final reported value. Compare against a limiting case: zero disturbance, zero controller gain, vanishing sample time, or a stationary equilibrium as appropriate. If a calculation predicts infinite control force, negative dissipation, or motion through a hard stop, that is an indication to revisit assumptions, not a valid operating instruction.