28 research outputs found
Evolutionary algorithms for optimal control in fed-batch fermentation processes
In this work, Evolutionary Algorithms (EAs) are used to achieve optimal feedforward control in a recombinant bacterial fed-batch
fermentation process, that aims at producing a bio-pharmaceutical product.
Three diferent aspects are the target of the optimization procedure: the feeding trajectory (the amount of substrate introduced in a bioreactor per time unit), the duration of the fermentation and the initial conditions
of the process. A novel EA with variable size chromosomes and using real-valued representations is proposed that is capable of simultaneously optimizing the aforementioned aspects. Outstanding productivity levels
were achieved and the results are validated by practice
Differential evolution for the offline and online optimization of fed-batch fermentation processes
The optimization of input variables (typically feeding trajectories over
time) in fed-batch fermentations has gained special attention, given the economic impact
and the complexity of the problem. Evolutionary Computation (EC) has been a
source of algorithms that have shown good performance in this task. In this chapter,
Differential Evolution (DE) is proposed to tackle this problem and quite promising
results are shown. DE is tested in several real world case studies and compared with
other EC algorihtms, such as Evolutionary Algorithms and Particle Swarms. Furthermore,
DE is also proposed as an alternative to perform online optimization, where the
input variables are adjusted while the real fermentation process is ongoing. In this case,
a changing landscape is optimized, therefore making the task of the algorithms more
difficult. However, that fact does not impair the performance of the DE and confirms
its good behaviour.(undefined
Bioprocess modeling and optimization: Fed-batch clavulanic acid production by streptomyces clavuligerus
Applied Science
Fuzzy model-based predictive control using Takagi-Sugeno models
Nonlinear model-based predictive control (MBPC) in multi-input multi-output (MIMO) process control is attractive for industry. However, two main problems need to be considered: (i) obtaining a good nonlinear model of the process, and (ii) applying the model for control purposes. In this paper, recent work focusing on the use of Takagi-Sugeno fuzzy models in combination with MBPC is described. First, the fuzzy model-identification of MIMO processes is given. The process model is derived from inputoutput data by means of product-space fuzzy clustering. The MIMO model is represented as a set of coupled multi-input, single-output (MISO) models. Next, the Takagi-Sugeno fuzzy model is used in combination with MBPC. The critical element in nonlinear MBPC is the optimization routine which is nonconvex and thus difficult to solve. Two methods to deal with this problem are developed: (i) a branch-and-bound method with iterative grid-size reduction, and (ii) control based on a local linear model. Both m..