Pub Date : 2026-01-13DOI: 10.1016/j.conengprac.2026.106764
Sen Li , Qi Chen , Weihua Li , Mingfeng Wang , Sungsung Pang , Kai Wu
Robotic ultrasound systems can improve imaging consistency and reduce operator workload by maintaining stable probe–tissue contact forces. However, variations in tissue stiffness and surface position often degrade force-tracking performance. This paper presents a disturbance observer–based sliding mode admittance control (DOSMAC) framework to address these challenges. Stiffness and position variations are uniformly modeled as lumped external disturbances, estimated online by a disturbance observer and compensated through sliding mode control. The resulting signal is introduced as a virtual input to the admittance model, enhancing robustness without requiring online stiffness identification or extensive parameter tuning. The stability of the closed-loop system is established through Lyapunov analysis. Simulations and experiments with stiffness ranging from 500 to 3500 N/m verify the effectiveness of the proposed approach. In experiments with simultaneous stiffness and position variations, DOSMAC reduces overshoot by 29.1% and 55.4%, peak force error by 4.36 N and 0.46 N, and root mean square error by 1.79 N and 0.4 N, respectively, compared with conventional admittance control and adaptive variable admittance control. These results demonstrate that the proposed method enables stable and reliable force tracking under complex time-varying conditions, supporting the clinical translation forceof robotic ultrasound.
{"title":"Observer-based sliding mode admittance control for ultrasound robot force-tracking in complex interaction environments","authors":"Sen Li , Qi Chen , Weihua Li , Mingfeng Wang , Sungsung Pang , Kai Wu","doi":"10.1016/j.conengprac.2026.106764","DOIUrl":"10.1016/j.conengprac.2026.106764","url":null,"abstract":"<div><div>Robotic ultrasound systems can improve imaging consistency and reduce operator workload by maintaining stable probe–tissue contact forces. However, variations in tissue stiffness and surface position often degrade force-tracking performance. This paper presents a disturbance observer–based sliding mode admittance control (DOSMAC) framework to address these challenges. Stiffness and position variations are uniformly modeled as lumped external disturbances, estimated online by a disturbance observer and compensated through sliding mode control. The resulting signal is introduced as a virtual input to the admittance model, enhancing robustness without requiring online stiffness identification or extensive parameter tuning. The stability of the closed-loop system is established through Lyapunov analysis. Simulations and experiments with stiffness ranging from 500 to 3500 N/m verify the effectiveness of the proposed approach. In experiments with simultaneous stiffness and position variations, DOSMAC reduces overshoot by 29.1% and 55.4%, peak force error by 4.36 N and 0.46 N, and root mean square error by 1.79 N and 0.4 N, respectively, compared with conventional admittance control and adaptive variable admittance control. These results demonstrate that the proposed method enables stable and reliable force tracking under complex time-varying conditions, supporting the clinical translation forceof robotic ultrasound.</div></div>","PeriodicalId":50615,"journal":{"name":"Control Engineering Practice","volume":"169 ","pages":"Article 106764"},"PeriodicalIF":4.6,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980022","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 : 2026-01-13DOI: 10.1016/j.conengprac.2026.106760
Shuo Wang , Baorui Wang , Guoxiang Gu
This paper proposes rail-less trains, composed of electric buses which are coupled together. The dynamic model of the rail-less electric bus train (REBT) involves not only nonlinearities but also unknown and uncertain parameters, which pose significant challenges. To mitigate model nonlinearities and parameter uncertainties in practical REBT system, we develop centralized and distributed adaptive control laws based on high-order full actuation (HOFA) control. For developing the centralized adaptive control law, we propose a novel adaptive control method, integrating gamma-projection operators with sigma-modification in adaptive estimation. This method robustly constrains parameter estimates within the known set while suppressing drift and offering tradeoffs between the magnitudes of control signal and tracking performance. For developing the distributed adaptive control law, we propose a different adaptive control method, employing both autonomous and cooperative control actions and using again the gamma-projection. In addition, adaptive estimation is aided by an off-line least-squares (LS) algorithm that ensures the adaptive estimates to converge to the true system parameters under the persistent excitation condition, leading to asymptotic feedback linearization and global asymptotic stabilization. Disturbance rejection in the framework of -control is studied for the linearized REBT system. It is shown that the two proposed adaptive control laws ensure the -norm from the input disturbance to the output tracking errors for velocity and inter-EB-distance controls to be strictly smaller than any γ > 0, effectively suppressing energy bounded disturbances in the worst-case. The simulation study includes industrial-level simulators and validates the proposed adaptive control methods.
{"title":"Full actuation control for rail-less electric bus trains","authors":"Shuo Wang , Baorui Wang , Guoxiang Gu","doi":"10.1016/j.conengprac.2026.106760","DOIUrl":"10.1016/j.conengprac.2026.106760","url":null,"abstract":"<div><div>This paper proposes rail-less trains, composed of electric buses which are coupled together. The dynamic model of the rail-less electric bus train (REBT) involves not only nonlinearities but also unknown and uncertain parameters, which pose significant challenges. To mitigate model nonlinearities and parameter uncertainties in practical REBT system, we develop centralized and distributed adaptive control laws based on high-order full actuation (HOFA) control. For developing the centralized adaptive control law, we propose a novel adaptive control method, integrating gamma-projection operators with sigma-modification in adaptive estimation. This method robustly constrains parameter estimates within the known set while suppressing drift and offering tradeoffs between the magnitudes of control signal and tracking performance. For developing the distributed adaptive control law, we propose a different adaptive control method, employing both autonomous and cooperative control actions and using again the gamma-projection. In addition, adaptive estimation is aided by an off-line least-squares (LS) algorithm that ensures the adaptive estimates to converge to the true system parameters under the persistent excitation condition, leading to asymptotic feedback linearization and global asymptotic stabilization. Disturbance rejection in the framework of <span><math><msub><mi>H</mi><mi>∞</mi></msub></math></span>-control is studied for the linearized REBT system. It is shown that the two proposed adaptive control laws ensure the <span><math><msub><mi>H</mi><mi>∞</mi></msub></math></span>-norm from the input disturbance to the output tracking errors for velocity and inter-EB-distance controls to be strictly smaller than any <em>γ</em> > 0, effectively suppressing energy bounded disturbances in the worst-case. The simulation study includes industrial-level simulators and validates the proposed adaptive control methods.</div></div>","PeriodicalId":50615,"journal":{"name":"Control Engineering Practice","volume":"169 ","pages":"Article 106760"},"PeriodicalIF":4.6,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980023","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 : 2026-01-13DOI: 10.1016/j.conengprac.2026.106778
Xiaomei Cheng , Xutao Qu , Jiang Zhao , Ningjun Liu , Zhihao Cai , Yingxun Wang
Tilt-trirotor Unmanned Aerial Vehicles (UAVs) face coupled challenges in generating longitudinal acceleration and mapping virtual control inputs to actuator commands. This paper develops an integrated flight control strategy addressing both problems. First, a smooth nonlinear pitch-tilt coordination function is formulated to map desired longitudinal acceleration to attitude commands, ensuring continuous derivatives during acceleration reversals and improving tracking performance. Second, a structure-preserving control allocation framework is established using intermediate variables, expanding the feasible allocation space and enabling a priority-preserving saturation mechanism that safeguards critical channels such as roll while limiting less essential ones like yaw. Flight experiments demonstrate that, compared with baseline approaches, the proposed strategy reduces position error by up to 45.4% and enhances stability under demanding flight conditions.
{"title":"Longitudinal acceleration shaping and priority-aware control allocation for tilt-trirotor UAVs","authors":"Xiaomei Cheng , Xutao Qu , Jiang Zhao , Ningjun Liu , Zhihao Cai , Yingxun Wang","doi":"10.1016/j.conengprac.2026.106778","DOIUrl":"10.1016/j.conengprac.2026.106778","url":null,"abstract":"<div><div>Tilt-trirotor Unmanned Aerial Vehicles (UAVs) face coupled challenges in generating longitudinal acceleration and mapping virtual control inputs to actuator commands. This paper develops an integrated flight control strategy addressing both problems. First, a smooth nonlinear pitch-tilt coordination function is formulated to map desired longitudinal acceleration to attitude commands, ensuring continuous derivatives during acceleration reversals and improving tracking performance. Second, a structure-preserving control allocation framework is established using intermediate variables, expanding the feasible allocation space and enabling a priority-preserving saturation mechanism that safeguards critical channels such as roll while limiting less essential ones like yaw. Flight experiments demonstrate that, compared with baseline approaches, the proposed strategy reduces position error by up to 45.4% and enhances stability under demanding flight conditions.</div></div>","PeriodicalId":50615,"journal":{"name":"Control Engineering Practice","volume":"169 ","pages":"Article 106778"},"PeriodicalIF":4.6,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145979890","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 : 2026-01-12DOI: 10.1016/j.conengprac.2026.106758
Yulin Feng , Hailang Jin , Steven X. Ding , Hao Ye , Chao Shang
The robustness of fault detection algorithms against uncertainty is crucial in the real-world industrial environment. Recently, a new probabilistic design scheme called distributionally robust fault detection (DRFD) has emerged and received immense interest. Despite its robustness against unknown distributions in practice, current DRFD focuses on the overall detectability of all possible faults rather than the detectability of critical faults that are a priori known. Hence, a new DRFD trade-off design scheme is put forward in this work by utilizing prior fault information. The key contribution includes a novel distributional robustness metric of detecting a known fault and a new relaxed distributionally robust chance constraint that ensures robust detectability. Then, a new DRFD design problem of fault detection under unknown probability distributions is proposed, and this offers a flexible balance between the robustness of detecting known critical faults and the overall detectability against all possible faults. To address the resulting semi-infinite chance-constrained problem, we first reformulate it to a finite-dimensional problem characterized by bilinear matrix inequalities. Subsequently, a tailored heuristic solution algorithm is developed, which includes a sequential minimization procedure and an initialization strategy. Finally, case studies on a simulated three-tank system and a real-world battery cell are carried out to showcase the effectiveness of the proposed heuristic algorithm and the advantages of our DRFD method.
{"title":"Distributionally robust fault detection trade-off design with prior fault information","authors":"Yulin Feng , Hailang Jin , Steven X. Ding , Hao Ye , Chao Shang","doi":"10.1016/j.conengprac.2026.106758","DOIUrl":"10.1016/j.conengprac.2026.106758","url":null,"abstract":"<div><div>The robustness of fault detection algorithms against uncertainty is crucial in the real-world industrial environment. Recently, a new probabilistic design scheme called distributionally robust fault detection (DRFD) has emerged and received immense interest. Despite its robustness against unknown distributions in practice, current DRFD focuses on the overall detectability of all possible faults rather than the detectability of critical faults that are <em>a priori</em> known. Hence, a new DRFD trade-off design scheme is put forward in this work by utilizing prior fault information. The key contribution includes a novel distributional robustness metric of detecting a known fault and a new relaxed distributionally robust chance constraint that ensures robust detectability. Then, a new DRFD design problem of fault detection under unknown probability distributions is proposed, and this offers a flexible balance between the robustness of detecting known critical faults and the overall detectability against all possible faults. To address the resulting semi-infinite chance-constrained problem, we first reformulate it to a finite-dimensional problem characterized by bilinear matrix inequalities. Subsequently, a tailored heuristic solution algorithm is developed, which includes a sequential minimization procedure and an initialization strategy. Finally, case studies on a simulated three-tank system and a real-world battery cell are carried out to showcase the effectiveness of the proposed heuristic algorithm and the advantages of our DRFD method.</div></div>","PeriodicalId":50615,"journal":{"name":"Control Engineering Practice","volume":"169 ","pages":"Article 106758"},"PeriodicalIF":4.6,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145979888","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 : 2026-01-12DOI: 10.1016/j.conengprac.2025.106756
Marco Fernandes dos Santos Xaud , Pål Johan From , Antonio Candea Leite
This paper presents the mechanical design, constructive aspects, kinematic modeling and control design methodology for a hyper-constrained parallel mechanism (HCPM), composed of six closed kinematic chains and twelve spherical joints, which is developed to carry out high-precision robotic tasks in industrial and agricultural environments. Here, we employ a systematic modeling methodology which considers the kinematic constraints of the mechanism from its structure equations, rather than explicitly using the constraint equations. This allows us to describe the kinematic constraints in the operation velocity space instead of the joint configuration space. From this analytical approach, we can compute the velocity of the non-actuated joints as a function of the velocity of the actuated ones. The control design uses an inverse kinematics algorithm based on the pseudo-inverse Jacobian matrix. In order to deal with many potential singular configurations which may occur during the task execution, we consider a recently proposed approach, called the Filtered Inverse method, which dynamically estimates the inverse of the Jacobian matrix instead of computing its true inverse instantaneously. The dynamic control of the HCPM is achieved using a simplified, Lagrangian-derived model to provide the computed-torque feedforward term for nonlinear compensation and decoupling, enabling motion simulation for high-speed trajectories while dismissing the need for a full explicit model, which is complex and difficult to obtain. Despite the simplifications, a robust cascade control strategy is proposed—featuring a second-order sliding mode (STA) compensator—to handle modeling uncertainties effectively. 3D computer modeling, numerical simulations, and laboratory experiments with two prototypes of the hyper-constrained parallel mechanism were conducted to validate the proposed approach and demonstrate its feasibility for high-precision robotic tasks.
{"title":"Modeling and cascade-based robust dynamic control of a hyper-constrained parallel mechanism for high-precision robotic tasks","authors":"Marco Fernandes dos Santos Xaud , Pål Johan From , Antonio Candea Leite","doi":"10.1016/j.conengprac.2025.106756","DOIUrl":"10.1016/j.conengprac.2025.106756","url":null,"abstract":"<div><div>This paper presents the mechanical design, constructive aspects, kinematic modeling and control design methodology for a hyper-constrained parallel mechanism (HCPM), composed of six closed kinematic chains and twelve spherical joints, which is developed to carry out high-precision robotic tasks in industrial and agricultural environments. Here, we employ a systematic modeling methodology which considers the kinematic constraints of the mechanism from its structure equations, rather than explicitly using the constraint equations. This allows us to describe the kinematic constraints in the operation velocity space instead of the joint configuration space. From this analytical approach, we can compute the velocity of the non-actuated joints as a function of the velocity of the actuated ones. The control design uses an inverse kinematics algorithm based on the pseudo-inverse Jacobian matrix. In order to deal with many potential singular configurations which may occur during the task execution, we consider a recently proposed approach, called the Filtered Inverse method, which dynamically estimates the inverse of the Jacobian matrix instead of computing its true inverse instantaneously. The dynamic control of the HCPM is achieved using a simplified, Lagrangian-derived model to provide the computed-torque feedforward term for nonlinear compensation and decoupling, enabling motion simulation for high-speed trajectories while dismissing the need for a full explicit model, which is complex and difficult to obtain. Despite the simplifications, a robust cascade control strategy is proposed—featuring a second-order sliding mode (STA) compensator—to handle modeling uncertainties effectively. 3D computer modeling, numerical simulations, and laboratory experiments with two prototypes of the hyper-constrained parallel mechanism were conducted to validate the proposed approach and demonstrate its feasibility for high-precision robotic tasks.</div></div>","PeriodicalId":50615,"journal":{"name":"Control Engineering Practice","volume":"169 ","pages":"Article 106756"},"PeriodicalIF":4.6,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145979889","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 : 2026-01-11DOI: 10.1016/j.conengprac.2026.106759
Yun-Jie Pan , Yan-Ning Sun , Wei Qin , Zeng-Gui Gao , Li-Lan Liu
In continuous casting operations, mold level fluctuation (MLF) triggers slag entrapment within molten steel, resulting in surface imperfections of cast slabs, which underscores the imperative for anticipatory MLF prediction to guarantee both quality reliability and system safety. The nonlinear coupling interactions among multiple process parameters and dynamic time-varying operating conditions pose significant challenges to maintaining the sustained robust performance of current data-driven prediction models. Therefore, this study proposes a novel continual causal learning architecture integrating multiscale transfer entropy graph attention network with elastic weight consolidation. The framework achieves temporal-adaptive prediction through multiscale transfer entropy quantification of nonlinear parameter interactions, encoded as dynamic causal graphs to guide attention-based feature aggregation. An elastic weight consolidation mechanism preserves critical information learned from historical conditions while assimilating new operational knowledge, overcoming the catastrophic forgetting dilemma in traditional models. Sensor-specific embedding modules further enhance cross-condition generalization by extracting invariant features from different operating conditions. Experimental validation using real-world continuous casting data demonstrates superior performance, with RMSE reductions of 3.43% – 34.9% compared to mainstream methods across three operating conditions, while achieving an average R2 of 0.745. The proposed architecture provides a deployable solution for online MLF monitoring, enabling adaptive quality control in smart continuous casting systems through its interpretable causal reasoning and multi-condition adaptability.
{"title":"A continual causal learning architecture with multiscale graph attention for robust mold level fluctuation prediction in smart continuous casting systems","authors":"Yun-Jie Pan , Yan-Ning Sun , Wei Qin , Zeng-Gui Gao , Li-Lan Liu","doi":"10.1016/j.conengprac.2026.106759","DOIUrl":"10.1016/j.conengprac.2026.106759","url":null,"abstract":"<div><div>In continuous casting operations, mold level fluctuation (MLF) triggers slag entrapment within molten steel, resulting in surface imperfections of cast slabs, which underscores the imperative for anticipatory MLF prediction to guarantee both quality reliability and system safety. The nonlinear coupling interactions among multiple process parameters and dynamic time-varying operating conditions pose significant challenges to maintaining the sustained robust performance of current data-driven prediction models. Therefore, this study proposes a novel continual causal learning architecture integrating multiscale transfer entropy graph attention network with elastic weight consolidation. The framework achieves temporal-adaptive prediction through multiscale transfer entropy quantification of nonlinear parameter interactions, encoded as dynamic causal graphs to guide attention-based feature aggregation. An elastic weight consolidation mechanism preserves critical information learned from historical conditions while assimilating new operational knowledge, overcoming the catastrophic forgetting dilemma in traditional models. Sensor-specific embedding modules further enhance cross-condition generalization by extracting invariant features from different operating conditions. Experimental validation using real-world continuous casting data demonstrates superior performance, with RMSE reductions of 3.43% – 34.9% compared to mainstream methods across three operating conditions, while achieving an average <em>R</em><sup>2</sup> of 0.745. The proposed architecture provides a deployable solution for online MLF monitoring, enabling adaptive quality control in smart continuous casting systems through its interpretable causal reasoning and multi-condition adaptability.</div></div>","PeriodicalId":50615,"journal":{"name":"Control Engineering Practice","volume":"169 ","pages":"Article 106759"},"PeriodicalIF":4.6,"publicationDate":"2026-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980024","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 : 2026-01-10DOI: 10.1016/j.conengprac.2025.106751
Shuo Xue , Liang Yuan , Kai Lv , Teng Ran , Wendong Xiao , Jianbo Zhang
Quadruped robots rely on jumping ability to traverse discontinuous terrain and complex obstacles, allowing them to perform challenging tasks in dynamic and unpredictable environments. However, jumping control faces multiple challenges, including high-dimensional nonlinear dynamics, underactuation during flight, external disturbances, which make it difficult to ensure stability and robustness. Current reinforcement learning methods usually apply random disturbances only on the body of robot during training to improve jumping robustness. However, due to the high randomness, low accuracy and narrow application scope, the training effect is limited. To address these issues, this study proposes a reinforcement learning framework that systematically introduces disturbances on both the body and legs to improve overall stability. An adaptation module is designed to predict environmental and disturbance information, enhancing the quality of training data. Furthermore, a learnable disturbance generator based on H∞ regularization is introduced to dynamically generate appropriate disturbances according to the performance of the robot. The learned policy is deployed on a real quadruped robot and evaluated in complex indoor and outdoor environments. Experimental results demonstrate strong robustness and generalization of the learned policy, enabling stable and reliable jumping performance.
{"title":"Robust jumping control of quadruped robots under body and leg disturbances using reinforcement learning with H∞ regularization","authors":"Shuo Xue , Liang Yuan , Kai Lv , Teng Ran , Wendong Xiao , Jianbo Zhang","doi":"10.1016/j.conengprac.2025.106751","DOIUrl":"10.1016/j.conengprac.2025.106751","url":null,"abstract":"<div><div>Quadruped robots rely on jumping ability to traverse discontinuous terrain and complex obstacles, allowing them to perform challenging tasks in dynamic and unpredictable environments. However, jumping control faces multiple challenges, including high-dimensional nonlinear dynamics, underactuation during flight, external disturbances, which make it difficult to ensure stability and robustness. Current reinforcement learning methods usually apply random disturbances only on the body of robot during training to improve jumping robustness. However, due to the high randomness, low accuracy and narrow application scope, the training effect is limited. To address these issues, this study proposes a reinforcement learning framework that systematically introduces disturbances on both the body and legs to improve overall stability. An adaptation module is designed to predict environmental and disturbance information, enhancing the quality of training data. Furthermore, a learnable disturbance generator based on <em>H</em><sub>∞</sub> regularization is introduced to dynamically generate appropriate disturbances according to the performance of the robot. The learned policy is deployed on a real quadruped robot and evaluated in complex indoor and outdoor environments. Experimental results demonstrate strong robustness and generalization of the learned policy, enabling stable and reliable jumping performance.</div></div>","PeriodicalId":50615,"journal":{"name":"Control Engineering Practice","volume":"169 ","pages":"Article 106751"},"PeriodicalIF":4.6,"publicationDate":"2026-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928901","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 : 2026-01-09DOI: 10.1016/j.conengprac.2026.106757
Rami Jradi , Hala Rifaï , José Fermi Guerrero-Castellanos , Samer Mohammed
In this paper, a control strategy for an Actuated Ankle Foot Orthosis (AAFO) is proposed to provide the assistance needed by the wearer at the ankle joint level. The control scheme is based on a contraction-based active disturbance rejection controller (Cont-ADRC). It includes an estimation of the human muscular torque and difficult-to-capture external torques affecting the AAFO-wearer system at the ankle joint level alongside unmodeled dynamics by means of a nonlinear disturbance observer (NDOB). A contraction-based variable gain controller determines the amount of assistance to be provided by the AAFO to perform the movement in complement to the aforementioned muscular torque. The variable gain controller provides a compromise between the low frequency disturbance rejection and the high frequency measurement noise attenuation. Using a contraction-based differential Lyapunov analysis, the trajectories of the AAFO-wearer system subject to the proposed active disturbance rejection controller are proved to be incrementally bounded, which is considered to be a stronger form of boundedness with respect to the uniform one. To demonstrate the efficiency of the Cont-ADRC, it has been applied in real-time experiments with robustness tests, involving three healthy subjects during walking activities. The outcomes revealed its superiority over other ADRCs developed for wearable robotics where it showed improved tracking accuracy compared to PID and Control Lyapunov Functions-based ADRC and reduced computational efforts compared to adaptive-based ADRC.
{"title":"Contraction-based active disturbance rejection controller for an active ankle foot orthosis","authors":"Rami Jradi , Hala Rifaï , José Fermi Guerrero-Castellanos , Samer Mohammed","doi":"10.1016/j.conengprac.2026.106757","DOIUrl":"10.1016/j.conengprac.2026.106757","url":null,"abstract":"<div><div>In this paper, a control strategy for an Actuated Ankle Foot Orthosis (AAFO) is proposed to provide the assistance needed by the wearer at the ankle joint level. The control scheme is based on a contraction-based active disturbance rejection controller (Cont-ADRC). It includes an estimation of the human muscular torque and difficult-to-capture external torques affecting the AAFO-wearer system at the ankle joint level alongside unmodeled dynamics by means of a nonlinear disturbance observer (NDOB). A contraction-based variable gain controller determines the amount of assistance to be provided by the AAFO to perform the movement in complement to the aforementioned muscular torque. The variable gain controller provides a compromise between the low frequency disturbance rejection and the high frequency measurement noise attenuation. Using a contraction-based differential Lyapunov analysis, the trajectories of the AAFO-wearer system subject to the proposed active disturbance rejection controller are proved to be incrementally bounded, which is considered to be a stronger form of boundedness with respect to the uniform one. To demonstrate the efficiency of the Cont-ADRC, it has been applied in real-time experiments with robustness tests, involving three healthy subjects during walking activities. The outcomes revealed its superiority over other ADRCs developed for wearable robotics where it showed improved tracking accuracy compared to PID and Control Lyapunov Functions-based ADRC and reduced computational efforts compared to adaptive-based ADRC.</div></div>","PeriodicalId":50615,"journal":{"name":"Control Engineering Practice","volume":"169 ","pages":"Article 106757"},"PeriodicalIF":4.6,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928904","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 : 2026-01-08DOI: 10.1016/j.conengprac.2025.106749
Mingyang Gao , Lina Wang , Xiangrong Song , Zhuoqing Li , Dazhong Ma
In blast furnace (BF) smelting, the permeability index (PI) is a key metric for evaluating whether the process is progressing toward optimal operating conditions. However, developing an effective prediction method for PI is challenging due to the influence of entangled temporal dependencies and the intrinsic non-stationarity of BF time series data. To address these challenges, a multivariate time series predictor based on orthogonal dynamic Koopman for BF PI prediction is proposed in this paper. Firstly, a feature decoupling (FD) module is designed, which uses a data-adaptive transformation based on an orthogonal matrix to effectively mitigate the impact of redundancy introduced by coupled variables. The feature decoupling module can be incorporated into the predictor to more effective the encoding and decoding within the decorrelated feature space. Subsequently, the multivariate BF time series, segmented using a sliding-window strategy, are projected into the Koopman embedding space via a multi-layer perceptron to extract interpretable dynamic modes. Furthermore, context-aware Koopman operator calculations are adaptively performed using extended dynamic mode decomposition (eDMD) across different temporal windows. This approach enables the approximation of non-stationary dynamics as locally linear, capturing the temporal evolution within each segment. Finally, comparative simulations with state-of-the-art models demonstrate that the proposed method achieves superior PI prediction performance.
{"title":"ODKP: A multivariate time series predictor based on orthogonal dynamic Koopman operator for blast furnace permeability index prediction","authors":"Mingyang Gao , Lina Wang , Xiangrong Song , Zhuoqing Li , Dazhong Ma","doi":"10.1016/j.conengprac.2025.106749","DOIUrl":"10.1016/j.conengprac.2025.106749","url":null,"abstract":"<div><div>In blast furnace (BF) smelting, the permeability index (PI) is a key metric for evaluating whether the process is progressing toward optimal operating conditions. However, developing an effective prediction method for PI is challenging due to the influence of entangled temporal dependencies and the intrinsic non-stationarity of BF time series data. To address these challenges, a multivariate time series predictor based on orthogonal dynamic Koopman for BF PI prediction is proposed in this paper. Firstly, a feature decoupling (FD) module is designed, which uses a data-adaptive transformation based on an orthogonal matrix to effectively mitigate the impact of redundancy introduced by coupled variables. The feature decoupling module can be incorporated into the predictor to more effective the encoding and decoding within the decorrelated feature space. Subsequently, the multivariate BF time series, segmented using a sliding-window strategy, are projected into the Koopman embedding space via a multi-layer perceptron to extract interpretable dynamic modes. Furthermore, context-aware Koopman operator calculations are adaptively performed using extended dynamic mode decomposition (eDMD) across different temporal windows. This approach enables the approximation of non-stationary dynamics as locally linear, capturing the temporal evolution within each segment. Finally, comparative simulations with state-of-the-art models demonstrate that the proposed method achieves superior PI prediction performance.</div></div>","PeriodicalId":50615,"journal":{"name":"Control Engineering Practice","volume":"169 ","pages":"Article 106749"},"PeriodicalIF":4.6,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928900","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 : 2026-01-08DOI: 10.1016/j.conengprac.2025.106712
Dana Copot, Bora Ayvaz, Erhan Yumuk
This study introduces a mechanistic, high-fidelity simulation environment for continuous direct compaction (CDC) tablet manufacturing, integrating feeders, blender, hopper, and tablet press models into a unified framework. The platform realistically captures material flow dynamics, residence time effects, and multivariable interactions, providing a robust virtual environment for in silico control design and testing. A disturbance-aware feedforward-feedback control architecture is evaluated across realistic scenarios, including upstream flowrate and concentration disturbances, raw material variability (±10-20% bulk density changes), and model-plant mismatch. Results demonstrate the platform’s capability to systematically assess control performance and robustness, supporting safe optimization of manufacturing processes. This work lays the foundation for scalable, model-informed control development and de-risking of future plant-wide control strategies, aligning with the Pharma 4.0 vision of predictive and adaptive continuous pharmaceutical manufacturing.
{"title":"Realistic process simulator for control strategy evaluation in continuous direct compaction tablet manufacturing","authors":"Dana Copot, Bora Ayvaz, Erhan Yumuk","doi":"10.1016/j.conengprac.2025.106712","DOIUrl":"10.1016/j.conengprac.2025.106712","url":null,"abstract":"<div><div>This study introduces a mechanistic, high-fidelity simulation environment for continuous direct compaction (CDC) tablet manufacturing, integrating feeders, blender, hopper, and tablet press models into a unified framework. The platform realistically captures material flow dynamics, residence time effects, and multivariable interactions, providing a robust virtual environment for in silico control design and testing. A disturbance-aware feedforward-feedback control architecture is evaluated across realistic scenarios, including upstream flowrate and concentration disturbances, raw material variability (±10-20% bulk density changes), and model-plant mismatch. Results demonstrate the platform’s capability to systematically assess control performance and robustness, supporting safe optimization of manufacturing processes. This work lays the foundation for scalable, model-informed control development and de-risking of future plant-wide control strategies, aligning with the Pharma 4.0 vision of predictive and adaptive continuous pharmaceutical manufacturing.</div></div>","PeriodicalId":50615,"journal":{"name":"Control Engineering Practice","volume":"169 ","pages":"Article 106712"},"PeriodicalIF":4.6,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928903","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}