Comparison of classical state space control and fuzzy control

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Comparison of classical state space control and
fuzzy control

• Felix Bierbaum

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State space control

• Based on mathematical model of the physical
  system
• Continuous time or discrete time
• Laplace transforms or z-transforms

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Fuzzy Control

• Based on rules
• No explicit mathematical model needed
• Always discrete time

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Example Roll bite
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Mathematical model


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Block diagram of state space controller
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Fuzzy sets
HEIGT Low (L), Little Low (LL), OK, Little High
(LH) and High (H) ANGLE Negative (N), Negative
small (NS), Zero (Z), Positive small (PS) and
Positive LEFT Down (LD), Little Down (LLD),
Still (LS), Little up (LLU) and Up (LU) LEFT
Down (RD), Little Down (RLD), Still (RS), Little
up (RLU) and Up (RU)
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Rule base
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Simulation results

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Conclusions
Fuzzy Control
State space control

• Good performance
• No mathematical model needed
• No metrics for evaluation

• Better performance
• Mathematical model needed
• Metrics for evaluation (command tracking, dynamic
  stiffness...)