1. Robust and Reliability Based Optimization using
VisualDOC-VeroSOLVE Interface
Dipankar Ghosh, Ph.D.
Vladimir Balabanov, Ph.D.
Vanderplaats Research & Development, Inc.
1767 S. 8th Street Colorado Springs, CO 80906
Ph. (719)
Copyright VR&D 2003
www. vrand.com

2. Outline Business Challenges What is VisualDOC? What is VeroSOLVE?
Robust Design/Reliability based optimization
What is VisualDOC?
Main features
What is VeroSOLVE?
What is VisualDOC-VeroSOLVE Interface?
Performing robust design/Reliability based optimization
Example
Conclusion / Questions

3. Business Challenges
How to be Successful, and stay successful over the long run
Two important strategies
Product quality
Increased productivity
How to implement these strategies
Use innovative design methods/tools during the whole product cycle management (PLM)
Address key design requirements early in the lifecycle
Use Robust design/Reliability based optimization to improve quality

4. Robust Design Numerical Optimization Probabilistic Design
allows us to make best usage of the resources while satisfying certain deterministic targets; uncertainties are not addressed
Probabilistic Design
Addresses uncertainties through the usage of random variables
Robust Design Approach
Numerical optimization and probabilistic design methods should be combined to best utilize the available resources while addressing the uncertainty issues, and thus create quality (robust) designs.

5. Robust Design
Robust design is an extension of deterministic numerical optimization
Noise factors - uncontrollable factors
The environmental parameters such as humidity levels, operating temperatures, raw materials, product aging, etc.
Control factors
geometric parameters, materials, design configurations, manufacturing process etc.
Find the appropriate levels of the controlled parameters such that the final design is insensitive (or robust) to changes in a set of noise factors.

6. What is VisualDOC? Graphics Based Design Optimization Software
General Optimization (Gradient & Non-Gradient)
Design Of Experiments
Response Surface Optimization
Allows User to Interface Optimization Tools with Almost Any Analysis (or Physical Experiment)
Modules Available as APIs For Easy Integration with other Control Programs

7. VisualDOC

8. VisualScript

9. Probabilistic analysis software
What is VeroSOLVE?
Probabilistic analysis software
Probability/Reliability analysis
Inverse probability analysis
PDF/CDF analysis
A number of probability methods
Graphically link VeroSOLVE with external analysis program
Synthetic functions (like in VisualDOC)

10. What is VeroSOLVE?

11. VisualDOC-VeroSOLVE Interface
Use VeroSOLVE software as analysis tool inside the VisualDOC software
It allows to access the majority of VeroSOLVE probabilistic analysis capabilities
Input Parameters
VisualDOC
Probabilistic Code
Analysis Code(s)
Output Parameters
VisualScript

12. VisualDOC-VeroSOLVE Interface
What can we do with this interface?
Reliability based optimization
System probability of failure and probability of failure for responses are used as objective and constraints
Robust Design
To reduce the standard deviation of certain responses
Combination of reliability and robust design

13. VisualDOC-VeroSOLVE Interface
Design Variables (Control Factors):
i=1,n
Random Variables (Noise Factors):
j=1,m
VeroSOLVE
Optimization loop
Probabilistic loop
VisualDOC
qDirect Optimization
qResponse Surface Optimization
Determine: μ and σ for responses of interest.
MaxMin

14. VisualDOC-VeroSOLVE Interface
VeroSOLVE users:
Can automatically export data into VisualDOC
Setting up optimization parameters in VisualDOC is an intuitive process
VisualDOC users:
Will find that defining variables, responses, and probability analysis parameters in VeroSOLVE is an easy task

15. VisualDOC-VeroSOLVE Interface
Steps
Setup a probability analysis problem in VeroSOLVE
Import the problem definition from VeroSOLVE into VisualDOC
Setup optimization parameters in VisualDOC
Specify VeroSOLVE as an analysis for VisualDOC
Run optimization

16. VisualDOC-VeroSOLVE Interface
Functionality
All VisualDOC functionality is available
gradient-based optimization methods
response surface optimization
non-gradient optimization
design of experiments
Some restrictions apply to VeroSOLVE problem aspects that can be exported into VisualDOC
e.g., probability analysis only

17. Example: Hydraulic Piston Design
Design Variables:
Piston position: X1, X2, X3
Piston diameter: D
All variables have
constant standard deviations

18. Example: Hydraulic Piston Design
Constraints:
Maximum bending moment of lifting beam
Force equilibrium
Pivot position
Support position

19. Example: Hydraulic Piston Design
Deterministic Optimization:
Minimize the volume of oil required to lift a specified load from 0 to 45 degrees
Robust Optimization:
Minimize the standard deviation of the oil volume
Additional constraint on the maximum volume of oil required to lift a specified load from 0 to 45 degrees

20. Example: Hydraulic Piston Design Results
initial deterministic robust
design optimum optimum X X X D
V (volume of oil)
standard deviation of V
Initial design had a severe violation of constraints
Robust optimum vs. deterministic optimum:
12.6 % reduction in the standard deviation of objective
1 % increase in the value of the objective function

21. Summary/Conclusions
Powerful VisualDOC/VeroSOLVE easy-to-use interface is created
Interface expands the functionality of both software systems
Allows solving reliability and robust optimization problems

22. Thank you!