Performance Improvement of Predictive Control Based on Model Mismatch Correction

Author(s):  
Zhen Huang ◽  
Lijuan Li
2016 ◽  
Author(s):  
Maxim Stuckert

This thesis deals with the nonlinear full state observer for distillation processes first introduced by Lang and Gilles in 1990. The observer is very attractive in practice as it requires only few temperature measurements in each section of a distillation column and only few observer parameters need to be tuned. We provide conditions under which this observer converges and derive a simple rule for the tuning of the observer parameters. We also give a method for the on-line estimation of the Murphree tray efficiency. Such on-line methods are rarely found in ­literature. In a sequence of simulation studies, we investigate the capabilities of the observer for the estimation of the tray efficiency and for model-predictive control. The simulation studies are based on distillation processes for separation of multicomponent mixtures and one of the studies introduces a plant-model mismatch. ...


2010 ◽  
Vol 43 ◽  
pp. 308-311 ◽  
Author(s):  
Rong Biao Zhang ◽  
Xian Lin Huang ◽  
Li Hong Wang ◽  
Jing Jing Guo

In view of characteristics of large time delay, multi-interference and strong coupling in temperature and humidity control system, an adaptive decoupling strategy based on generalized predictive control (GPC) and multi-model control is proposed in this paper. The proposed strategy mainly contains muti-model control, GPC decoupling control and adaptive algorithm. In multi-model control, multi-model sets are established to prevent the model mismatch in different working conditions. Meanwhile, this paper designs adaptive dynamic decoupling algorithms based on the principle of GPC. In actual experiments, temperature and humidity achieve precision of ±0.2°C and ±0.5% respectively.


2021 ◽  
Vol 15 ◽  
Author(s):  
Wenjun Liu ◽  
Chang Liu ◽  
Guang Chen ◽  
Alois Knoll

This paper proposes a novel framework for addressing the challenge of autonomous overtaking and obstacle avoidance, which incorporates the overtaking path planning into Gaussian Process-based model predictive control (GPMPC). Compared with conventional control strategies, this approach has two main advantages. Firstly, combining Gaussian Process (GP) regression with a nominal model allows for learning from model mismatch and unmodeled dynamics, which enhances a simple model and delivers significantly better results. Due to the approximation for propagating uncertainties, we can furthermore satisfy the constraints and thereby the safety of the vehicle is ensured. Secondly, we convert the geometric relationship between the ego vehicle and other obstacle vehicles into the constraints. Without relying on a higher-level path planner, this approach substantially reduces the computational burden. In addition, we transform the state constraints under the model predictive control (MPC) framework into a soft constraint and incorporate it as relaxed barrier function into the cost function, which makes the optimizer more efficient. Simulation results indicate that the proposed method can not only fulfill the overtaking tasks but also maintain safety at all times.


2018 ◽  
Vol 67 ◽  
pp. 03012
Author(s):  
Abdul Wahid ◽  
Naufal Syafiq Maro

Currently, Indonesia is still experiencing a fuel deficit, so it is necessary to build a new oil refinery and a process optimization at an existing refinery. A vacuum distillation unit (VDU) is used to process the atmospheric residue products from crude distillation unit (CDU). A multivariable model predictive control (MMPC) is proposed to improve a control performance in VDU because of the interaction between variables in the unit. Therefore, it is necessary to find the variables that interact with each other. In this study only two variables are discussed. Set point (SP) and disturbance changes are used to test the control performance with integral of square error (ISE) as the indicator. The results are compared with the control performance of the PI controller and a single MPC. As a result, the feed flow rate and bottom-stage temperature are strongest interactions so that both are determined as controlled variables in MMPC. The control performance of MMPC is better than the PI controller and the single MPC with control performance improvement of 48% to the PI controller and 21% to MPC on for Feed Flow Rates, and 98% to the PI controller and 27% to MPC on Bottom Stage Temperature. While on disturbance changes the enhancement is 35% for the Bottom Stage Temperature.


2017 ◽  
Vol 104 ◽  
pp. 5-14 ◽  
Author(s):  
Siyun Wang ◽  
Jodie M. Simkoff ◽  
Michael Baldea ◽  
Leo H. Chiang ◽  
Ivan Castillo ◽  
...  

Author(s):  
Adam Parry ◽  
Brandon Hencey ◽  
Jon Zumberge

Abstract In this paper, the problem of controlling synchronous machines driving high pulsed, constant-power loads (CPLs) with fast ramp rates is investigated. Using a PI controller to provide offset-free tracking of the generator voltage in steady state, we design controllers using Model Predictive Control which act as a reference governor to ensure power quality constraints are met during transients. However, it is shown that a standard linear MPC algorithm creates a steady state offset due to model mismatch at off-nominal power levels resulting in loss of power quality. This problem is corrected by creating multiple linear models of the generator dynamics linearized around the nominal and high power operating points. We then demonstrate that a Hybrid Model Predictive Control algorithm (using the constrained piecewise affine prediction model) exhibits zero offset during the high power pulse. The Hybrid MPC algorithm also keeps the generator voltage within the required constraints. This approach has the benefit of correcting the model mismatch issue without using a computationally expensive nonlinear Model Predictive Control algorithm. Future work will focus on implementing and testing this hybrid MPC controller on a generator via explicit MPC techniques.


2014 ◽  
Vol 651-653 ◽  
pp. 966-971
Author(s):  
Rao Bin

Network latency was usually uncertain or random, and the packet loss and temporal disorders could also be attributed to a certain degree of time delay. This paper briefly described the basic principle of predictive control and deduced the predictive control algorithm based on Toeplitz equation, finally combined with the simulation example to verify the validity and superiority of the new algorithm, from the operation speed of the algorithm, the signal tracking capabilities when time delay existed, and performance for overcoming the influence of model mismatch.


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