Optimization
aspenONE APC offers three approaches to optimization. The
controllers themselves embody objective functions that are used to
drive the controller to desired constraints. Each control
formulation has a unique solver and objective function.
Controller Objective Functions
Aspen DMCplus® (FIR Model)
Algorithm is a revised simplex method for LPs and interior point
for QPs. Interior point can also be used for LPs. Also provides
upper and lower ranked limits for CVs (linear or quadratic type).
Ranked ETs can be specified on inputs and outputs and also include
costs.
State Space (MISO Model)
Algorithm is an SQP. Each QP iteration uses the interior point
method. Trust regions are used to expand the search region and can
include upper and lower ranked limits for CVs (linear or quadratic
type). Ranked targets can be specified on inputs and outputs
(target can be an ET or upper or lower limit or minimum move). They
can also take into account costs on inputs and outputs.
State Space (MIMO Model)
Algorithm is an interior point method that can include upper and
lower ranked limits for CVs (only quadratic). Ranked ETs can be
specified on inputs and outputs and also include costs.
Composite Linear Program
Some processes pose a scale challenge when they involve multiple
controllers and process sections with significantly different
dynamics. For these challenges, aspenONE APC offers the Composite
Linear Program (CLP).
- Links the LPs of different controllers in one
CLP to cover a broad scope of plant (in terms of active
constraints) in one structure
- Enables coordination across multiple
controllers
- Introduces more detailed and wider scope of
economics
- Allows larger scale solutions
- Reduces controller tweaking to accommodate
changing economics
Aspen Real-Time Optimizer
Aspen Real-Time Optimizer provides a comprehensive
solution to the challenge of optimizing process profitability,
determining the optimal targets for individual process units
considering the conditions across the entire process. It provides
robust convergence for real-time solutions with models complex
enough to address true unit economics. aspenONE® Advanced Process
Control is a core element of Aspen Real-Time
Optimizer.
Aspen RTO Watch Performance Monitor
Aspen RTO Watch Performance Monitor is a layered
product that provides full historization and visualization of all
optimizer-related data. This allows support engineers-using
accumulated history-to identify trends, problems, and potential
areas for improvement. It also provides a range of performance
monitoring and diagnostic features.