SLIDE 1 High Warehouse Racks: Optimal Feedback Control and High Warehouse Racks: Optimal Feedback Control and Adaptive Control Improvement Adaptive Control Improvement
Christof Bü Christof Büskens skens
INRIA, Optimal Control: Algorithms and Applications (May/June 2007)
SLIDE 2 2 Classification of Optimal Control Solutions
closed-loop:
SLIDE 3 3 Open-Loop vs. Closed-Loop
nonlinear linear Model Method
closed-loop knowledge Part I Part II
SLIDE 4
4 Part II linear closed-loop nonlinear closed-loop
SLIDE 5
5 Topic Slide: Optimal Control of Cranes
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6
Optimal Control Problem for High-Rack Trolley
SLIDE 7 7
– Example: Warehouse Cranes
- Part II: (Linear Quadratic Regulator (LQR))
– Perturbed Optimal Control Problems – Linear Quadratic Regulator Problems (LQR)
- Discussion
- Solution
- LQR vs. NLP
– Example: Warehouse Crane
- Part III: (Perturbed Linear Quadratic Regulator)
– Perturbed Linear Quadratic Regulator (Riccati) – Real-Time Optimal Adaption of Optimal Controllers – Example: Inverse Pendulum
Overview
SLIDE 8 8
Methods for solving Optimal Control Problems
- The result of any performance process is limited by the most
scarcely available ressource: the Time. (Drucker)
- We have enough Time, if only we use it wisely. (Goethe)
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9
Optimal Control Problems with Perturbations: ODE
SLIDE 10
10 Linear Quadratic Regulator (LQR)
SLIDE 11 11
– Example: Warehouse Cranes
- Part II: (Linear Quadratic Regulator (LQR))
– Perturbed Optimal Control Problems – Linear Quadratic Regulator Problems (LQR)
- Discussion
- Solution
- LQR vs. NLP
– Example: Warehouse Crane
- Part III: (Perturbed Linear Quadratic Regulator)
– Perturbed Linear Quadratic Regulator (Riccati) – Real-Time Optimal Adaption of Optimal Controllers – Example: Inverse Pendulum
Overview
SLIDE 12
12 Explanations: The Model
SLIDE 13
13 Explanations: The Quadratic Objective
SLIDE 14
14 Explanations: The Quadratic Objective
SLIDE 15
15 Explanations: The Quadratic Objective
SLIDE 16
16 Summing up the Explanations
SLIDE 17 17
– Example: Warehouse Cranes
- Part II: (Linear Quadratic Regulator (LQR))
– Perturbed Optimal Control Problems – Linear Quadratic Regulator Problems (LQR)
- Discussion
- Solution
- LQR vs. NLP
– Example: Warehouse Crane
- Part III: (Perturbed Linear Quadratic Regulator)
– Perturbed Linear Quadratic Regulator (Riccati) – Real-Time Optimal Adaption of Optimal Controllers – Example: Inverse Pendulum
Overview
SLIDE 18 18 Approach using the Hamiltonian
Methods:
- Pontryagin‘s Minimum Principle
- Calculus of variations
- Hamilton-Jacobi-Bellmann equation
- Karush-Kuhn-Tucker conditions
- Dynamical Optimization
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19 Approach using the Hamiltonian
SLIDE 20
20 Relationship: Hamiltonian LQR-Problem
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21 Strictly Local Minimum
SLIDE 22
22 The Suspicion
SLIDE 23
23 Resolution (with )
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24 Algebraic Matrix-Riccati-Equation
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25 Summary
SLIDE 26
26 Extension
SLIDE 27
27 Extension
SLIDE 28 28 Solution of LQR
click me
SLIDE 29
29 Alternative Formulations and Equivalences (LQR) (NLP)
SLIDE 30
30 Sparse NLP Solver
WORHP We Optimize Really Huge Problems
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31 WORHP Born for Space Applications
SLIDE 32 32 Reverse Communication Advantages
Simple implementation No worries after start
Caller
Evaluation Objective Gradient Evaluation Constraints Jacobian
Disadvantages
Inflexible user-interface No influence after start
Traditional Calling Sequence:
SQP
SLIDE 33 33 Reverse Communication Caller
New Calling Sequence: Evaluation Objective Gradient Evaluation Constraints Jacobian
Advantages Flexible problem evaluation Full control on optimization Disadvantages Harder to implement
WORHP
SLIDE 34
34 Features of WORHP: Sentinel
User Solution
WORHP Sentinel
SLIDE 35 35 Modularity
Modules to adapt to the User‘s requirements: Speed, Precision, Robustness, Simplicity, …
Gradient Fixed Stepsize Gradient Adaptive Stepsize Gradient Group Strategy Advanced Error Reporting Matrix structure Creation/Analysis Pre-Iteration- Analysis
WORHP QPSOL
QP-Matrix diagonal-BFGS QP-Matrix Hessian QP-Matrix Identity QP-Matrix diag.-Hessian QP-Method Nonsmooth Newton QP-Method Interior Point direct Solvers MA47, SuperLU iterative Solvers CGN, CGS, BiCG Interface Transcriptor Interface Reverse Comm. Interface Traditional Interface AMPL
SLIDE 36
36 Warehouse Crane
SLIDE 37 37 Topic Slide: Optimization in High Rack Technology
Modeling (Real-Time) Optimization:
- time
- energy
- jerk
- scillatory behavior
- non-oscillating at
Extended Constraints:
- controlled stop
- emergency stop
- collision free
Extended Modeling
- transfers from/into stock
- robustness
- intermediate stop
with: Westfalia Logistics
SLIDE 38
38 Emergency Stop
SLIDE 39 39
– Example: Warehouse Cranes
- Part II: (Linear Quadratic Regulator (LQR))
– Perturbed Optimal Control Problems – Linear Quadratic Regulator Problems (LQR)
- Discussion
- Solution
- LQR vs. NLP
– Example: Warehouse Crane
- Part III: (Perturbed Linear Quadratic Regulator)
– Perturbed Linear Quadratic Regulator (Riccati) – Real-Time Optimal Adaption of Optimal Controllers – Example: Inverse Pendulum
Overview
SLIDE 40
40 Perturbed Linear Quadratic Regulator
SLIDE 41
41 Perturbed NLP problems
SLIDE 42 42
Parametric Sensitivity Analysis / Solution Differentiability
SLIDE 43 43
Real-Time Optimization (General Idea)
Unperturbed Problem Sensitivity Analysis
Real-Time Optimization Real-Time Optimal Control
Sensitivities Solution Solution
SLIDE 44
44 Real-Time Optimization
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Existence und Uniqueness of perturbed Optimal Controllers
SLIDE 46 46
Real-Time Optimal Adaption of the Optimal Controller
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47 Error Estimate
SLIDE 48
48 Optimal Control of the Warehouse Crane Optimal Control of the Inverse Pendulum
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49 Application: The Inverse Pendulum
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50 Horizontally Acting Forces
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51 Further Forces
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52 Motivation: Inverse Pendulum
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53 Motivation: Inverse Pendulum (perturbed)
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54 Solution of the Inverse Pendulum
SLIDE 55 55
Adaptive Optimal Control: Inverse Pendulum (perturbed)
click me
SLIDE 56 56 Conclusion
- Optimal controllers are not optimal
– Perturbations and Real-Time Trajectory Planning – Perturbed Nonlinear Optimization – Sensitivity Analyses / Solution Differentiability – A New Class of Higher Order Optimal Ricatti Controllers
– Stabilizability – Controllability – Observability – Further assumption, e.g. PBH-Criteria – Extensions to the Ricatti Approach
- Optimal Controllers
- Tracking Type Controllers
- Dynamic Observers
- etc.
SLIDE 57
57 Thank You!