Pub Date : 2024-08-30DOI: 10.1109/TCST.2024.3445660
Gregory Conde;Sandra M. Guzmán
The challenge of increasing irrigation efficiency to meet the demands of a growing population while protecting natural resources requires the contributions of multiple disciplines, including engineering, agronomical, horticultural, and environmental sciences. Specifically, automatic control can play a pivotal role in improving irrigation scheduling. In this context, incorporating real-time soil moisture (SM) forecasting in irrigation can potentially improve the efficiency of crop water management. However, the complexity of the analytical models that describe soil-water dynamics limits the development of practical and accurate solutions that include SM forecasting in decision-making. Currently, irrigation decisions are based on present and past SM data. This approach can be enhanced if, in addition to those, future or SM forecasting is incorporated. We formulated an SM model-based moving horizon estimation (MHE) and prediction strategy. For this, we propose a parametrizable blue SM control-oriented prediction model (SMCOPM) that obeys a soil-water balance. The SMCOPM is periodically parametrized using a proposed MHE approach, which provides adaptability, guarantees optimality, prevents overfitting, and ensures the water balance fulfillment and stability of the SMCOPM. The SM forecasting is performed by solving the parametrized SMCOPM as a function of rain, irrigation, and temperature forecasts. We evaluated the MHE and prediction strategy using, as a case study, observed data from a commercial sweetcorn field using subsurface irrigation in South Florida. The results show that by using this strategy, the SM can be predicted three days in advance with an average SM prediction error and a dispersion that significantly improves as the SMCOPM adapts over time, demonstrating convergence toward an error less than 2% and dispersion less than 3%. Consequently, the results corroborate the SMCOPM suitability, the proposed estimation strategy’s quality, and the SM behavior’s predictability. The proposed strategy has the potential for use in formulating predictive control approaches toward automating the irrigation process or scheduling irrigation actions.
{"title":"Control-Oriented Forecasting for Soil Moisture","authors":"Gregory Conde;Sandra M. Guzmán","doi":"10.1109/TCST.2024.3445660","DOIUrl":"10.1109/TCST.2024.3445660","url":null,"abstract":"The challenge of increasing irrigation efficiency to meet the demands of a growing population while protecting natural resources requires the contributions of multiple disciplines, including engineering, agronomical, horticultural, and environmental sciences. Specifically, automatic control can play a pivotal role in improving irrigation scheduling. In this context, incorporating real-time soil moisture (SM) forecasting in irrigation can potentially improve the efficiency of crop water management. However, the complexity of the analytical models that describe soil-water dynamics limits the development of practical and accurate solutions that include SM forecasting in decision-making. Currently, irrigation decisions are based on present and past SM data. This approach can be enhanced if, in addition to those, future or SM forecasting is incorporated. We formulated an SM model-based moving horizon estimation (MHE) and prediction strategy. For this, we propose a parametrizable blue SM control-oriented prediction model (SMCOPM) that obeys a soil-water balance. The SMCOPM is periodically parametrized using a proposed MHE approach, which provides adaptability, guarantees optimality, prevents overfitting, and ensures the water balance fulfillment and stability of the SMCOPM. The SM forecasting is performed by solving the parametrized SMCOPM as a function of rain, irrigation, and temperature forecasts. We evaluated the MHE and prediction strategy using, as a case study, observed data from a commercial sweetcorn field using subsurface irrigation in South Florida. The results show that by using this strategy, the SM can be predicted three days in advance with an average SM prediction error and a dispersion that significantly improves as the SMCOPM adapts over time, demonstrating convergence toward an error less than 2% and dispersion less than 3%. Consequently, the results corroborate the SMCOPM suitability, the proposed estimation strategy’s quality, and the SM behavior’s predictability. The proposed strategy has the potential for use in formulating predictive control approaches toward automating the irrigation process or scheduling irrigation actions.","PeriodicalId":13103,"journal":{"name":"IEEE Transactions on Control Systems Technology","volume":"33 1","pages":"106-118"},"PeriodicalIF":4.9,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this brief, we propose a sequential convex programming (SCP) framework for minimizing the terminal state dispersion of a stochastic dynamical system about a prescribed destination—an important property in high-risk contexts such as spacecraft landing. Our proposed approach seeks to minimize the conditional value-at-risk (CVaR) of the dispersion, thereby shifting the probability distribution away from the tails. This approach provides an optimization framework that is not overly conservative and can accurately capture more information about true distribution, compared with methods which consider only the expected value, or robust optimization methods. The main contribution of this brief is to present an approach that: 1) establishes an optimization problem with CVaR dispersion cost 2) approximated with one of the two novel surrogates which is then 3) solved using an efficient SCP algorithm. In 2), two approximation methods, a sampling approximation (SA) and a symmetric polytopic approximation (SPA), are introduced for transforming the stochastic objective function into a deterministic form. The accuracy of the SA increases with sample size at the cost of problem size and computation time. To overcome this, we introduce the SPA, which avoids sampling by using an alternative approximation and thus offers significant computational benefits. Monte Carlo simulations indicate that our proposed approaches minimize the CVaR of the dispersion successfully.
{"title":"Dispersion Sensitive Optimal Control: A Conditional Value-at-Risk-Based Tail Flattening Approach via Sequential Convex Programming","authors":"Kazuya Echigo;Oliver Sheridan;Samuel Buckner;Behçet Açıkmeşe","doi":"10.1109/TCST.2024.3427910","DOIUrl":"10.1109/TCST.2024.3427910","url":null,"abstract":"In this brief, we propose a sequential convex programming (SCP) framework for minimizing the terminal state dispersion of a stochastic dynamical system about a prescribed destination—an important property in high-risk contexts such as spacecraft landing. Our proposed approach seeks to minimize the conditional value-at-risk (CVaR) of the dispersion, thereby shifting the probability distribution away from the tails. This approach provides an optimization framework that is not overly conservative and can accurately capture more information about true distribution, compared with methods which consider only the expected value, or robust optimization methods. The main contribution of this brief is to present an approach that: 1) establishes an optimization problem with CVaR dispersion cost 2) approximated with one of the two novel surrogates which is then 3) solved using an efficient SCP algorithm. In 2), two approximation methods, a sampling approximation (SA) and a symmetric polytopic approximation (SPA), are introduced for transforming the stochastic objective function into a deterministic form. The accuracy of the SA increases with sample size at the cost of problem size and computation time. To overcome this, we introduce the SPA, which avoids sampling by using an alternative approximation and thus offers significant computational benefits. Monte Carlo simulations indicate that our proposed approaches minimize the CVaR of the dispersion successfully.","PeriodicalId":13103,"journal":{"name":"IEEE Transactions on Control Systems Technology","volume":"32 6","pages":"2468-2475"},"PeriodicalIF":4.9,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-26DOI: 10.1109/TCST.2024.3443703
Josef Matouš;Kristin Y. Pettersen;Damiano Varagnolo;Claudio Paliotta
This article presents a distributed null-space-based behavioral (NSB) algorithm for the formation path-following problem of vehicles moving in three dimensions. The algorithm is applied to fleets of underactuated autonomous underwater vehicles (AUVs). The algorithm combines null-space-based control with consensus methods. First, we present a continuous-time version of the algorithm and prove its stability using Lyapunov analysis. Then, we present a discrete-time event-triggered version that, compared to similar formation path-following methods, can achieve the same steady state-error performance with fewer inter-vehicle transmissions. The effectiveness of both the continuous-time and the discrete-time algorithm is verified in numerical simulations. Furthermore, the discrete-time version is tested in experiments.
{"title":"A Distributed NSB Algorithm for Formation Path Following","authors":"Josef Matouš;Kristin Y. Pettersen;Damiano Varagnolo;Claudio Paliotta","doi":"10.1109/TCST.2024.3443703","DOIUrl":"10.1109/TCST.2024.3443703","url":null,"abstract":"This article presents a distributed null-space-based behavioral (NSB) algorithm for the formation path-following problem of vehicles moving in three dimensions. The algorithm is applied to fleets of underactuated autonomous underwater vehicles (AUVs). The algorithm combines null-space-based control with consensus methods. First, we present a continuous-time version of the algorithm and prove its stability using Lyapunov analysis. Then, we present a discrete-time event-triggered version that, compared to similar formation path-following methods, can achieve the same steady state-error performance with fewer inter-vehicle transmissions. The effectiveness of both the continuous-time and the discrete-time algorithm is verified in numerical simulations. Furthermore, the discrete-time version is tested in experiments.","PeriodicalId":13103,"journal":{"name":"IEEE Transactions on Control Systems Technology","volume":"33 1","pages":"16-31"},"PeriodicalIF":4.9,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Our power and energy systems are becoming more and more integrated and interconnected. The increasing integration of edge devices and dependence on cyber infrastructure provides both the potential for benefits and risks. The integration enables more dynamic and flexible control paradigms while at the same time increasing the cyberattack surface and uncertainty of behavior. Control methodology in this new world must be designed for resilience and must have the ability to withstand, react, and respond to both physical faults and cyber-induced threats [1]