{"title":"A Stochastic Approach to Maximal Output Admissible Sets and Reference Governors","authors":"Joycer Osorio, H. Ossareh","doi":"10.1109/CCTA.2018.8511439","DOIUrl":"https://doi.org/10.1109/CCTA.2018.8511439","url":null,"abstract":"This paper presents a stochastic approach to Reference Governors (RG) and Maximal Output Admissible Sets (MAS) using chance constraints. In order to construct a stochastic robustly invariant MAS (SR-MAS), we extend the earlier ideas in the literature to Lyapunov stable systems with output constraints. Formal proofs for important properties such as positive invariance and finite determinism of SR-MAS are provided. It is shown that the SR-MAS is less conservative than the deterministic approach. An algorithm is provided to compute the SR-MAS in finite time. Finally, we present a stochastic RG formulation, which leverages the SR-MAS. The main results are illustrated with a numerical simulation of a mass-spring-damper model with constraints imposed over the control signal and output.","PeriodicalId":358360,"journal":{"name":"2018 IEEE Conference on Control Technology and Applications (CCTA)","volume":"233 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123278291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Hybrid Integrator-Gain Based Low-Pass Filter for Nonlinear Motion Control","authors":"S. V. D. Eijnden, Y. Knops, M. Heertjes","doi":"10.1109/CCTA.2018.8511092","DOIUrl":"https://doi.org/10.1109/CCTA.2018.8511092","url":null,"abstract":"In this paper a hybrid low-pass filter is developed and subsequently embedded in a PID-based control design. The hybrid element switches between gain and integrator mode, depending on the evaluation of specifically designed switching conditions. Given the properties of the hybrid low-pass filter, which are mainly expressed by reduced phase lag as compared to a linear-equivalent low-pass filter, the bandwidth of the PID-based control design can potentially be increased. Based on describing function analysis, this bandwidth increase is obtained while identical robustness properties of the closed-loop system in terms of bounds imposed on the closed-loop sensitivity function are guaranteed. In this sense, the hybrid control design provides more design freedom compared to the equivalent linear control design, which leads to a factor two improvement in low-frequency disturbance suppression of a state-of-the-art scanning stage of an industrial wafer scanner.","PeriodicalId":358360,"journal":{"name":"2018 IEEE Conference on Control Technology and Applications (CCTA)","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123415440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Finite Time Optimal Preactuation for Non-Minimum Phase Systems Considering Control Input and Tracking Error Constraints","authors":"W. Ohnishi, Thomas Beauduin, H. Fujimoto","doi":"10.1109/CCTA.2018.8511355","DOIUrl":"https://doi.org/10.1109/CCTA.2018.8511355","url":null,"abstract":"To achieve perfect reference trajectory tracking, a plant with continuous time unstable zeros requires an infinite time preactuation. Albeit, this is practically infeasible, as typical high-precision motion systems target a short time finite preactuation. Truncating the control input to a limited time preactuation leads to undesirable tracking errors. This paper, thus, proposes a finite time preactuation method with an optimized state trajectory considering control input and tracking error constraints. The proposed method generates an optimal state trajectory for a given reference and finite time while explicitly considering the actuator, i.e. peak force, and stroke, i.e. maximum undershoot, limitations of the system. A multirate feedforward scheme is subsequently presented to obtain a discretized control input that perfectly tracks the designed optimal state trajectory. In comparison to conventional finite preactuation methods, the proposed approach reaches an order of magnitude lower tracking error bounds. Additionally, this finite time procedure attains, in contrast to conventional optimization approaches, through a multirate feedforward formulation, perfect tracking during the main motion after preactuation.","PeriodicalId":358360,"journal":{"name":"2018 IEEE Conference on Control Technology and Applications (CCTA)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125319149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Multi-Model Feedforward Dynamic Matrix Control of Polymer Membrane Fuel Cell with Dead-Ended Anode and Cyclic Purge Process","authors":"Tianyao Pan, Jiong Shen, Li Sun, Junli Zhang","doi":"10.1109/CCTA.2018.8511564","DOIUrl":"https://doi.org/10.1109/CCTA.2018.8511564","url":null,"abstract":"This paper proposes a control strategy for a Polymer Electrolyte Membrane Fuel Cell (PEMFC) with a dead-ended anode (DEA) and cyclic purge process using Multi-model Feedforward Dynamic Matrix Control (MFDMC) with a switch law. MFDMC is a model-based predictive control method, which has superiority in addressing control problems with constraints and nonlinearity. The control objective is to maintain a low differential pressure across the membrane against the disturbance of the purge process and load change. A mathematical model is built and its dynamics is recognized at varied operating conditions to demonstrate the transient behavior of a PEMFC stack. Simulation results show the ability of the MFDMC to compensate the influence of periodic purging and load change without constraint violation of the actuator.","PeriodicalId":358360,"journal":{"name":"2018 IEEE Conference on Control Technology and Applications (CCTA)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127047557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Model Predictive Roll Gap Control in Cold Rolling with Piezoelectric Actuators","authors":"Matthias Wehr, S. Stockert, D. Abel, G. Hirt","doi":"10.1109/CCTA.2018.8511333","DOIUrl":"https://doi.org/10.1109/CCTA.2018.8511333","url":null,"abstract":"In cold rolling, a precise roll gap adjustment is indispensable for manufacturing strips with accurate thickness. This paper proposes a linear model predictive controller for roll gap adjustment in a cold rolling mill. As part of an automatic gauge control, the precise roll gap adjustment according to the incoming strip thickness profile is vital. The measurement of that profile is buffered, filtered with a zero-phase and length-based filter and converted to a reference trajectory to meet the needs of a model predictive controller. Knowing the roll gap model as well as the actuator dynamics, the model predictive controller can adjust the roll gap according to incoming strip thickness disturbances right on time. Piezoelectric actuators are used for fast and precise adjustment. Results obtained in a cold rolling mill of industrial scale are shown.","PeriodicalId":358360,"journal":{"name":"2018 IEEE Conference on Control Technology and Applications (CCTA)","volume":"191 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115523682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Observer with Improved Convergence for a Class of Initialized FO-LTI Systems","authors":"C. Weise, K. Wulff, J. Reger","doi":"10.1109/CCTA.2018.8511326","DOIUrl":"https://doi.org/10.1109/CCTA.2018.8511326","url":null,"abstract":"In this contribution we investigate on the observer design for linear fractional-order (FO) systems which are excited by an unknown input in the past. The systems are assumed to have an order of differentiation less than one. We use an associated system of double-order of integration and design an unknown-input observer UIO) for this system such that a part of the memory effect is compensated. The higher order of differentiation also leads to an improved convergence of the estimation error. We present necessary and sufficient conditions for the existence of such unknown input observer. As a special case we investigate the order ‘one half’. In this case the estimation error decays exponentially and the entire memory is rejected in the integer-order error dynamics.","PeriodicalId":358360,"journal":{"name":"2018 IEEE Conference on Control Technology and Applications (CCTA)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129606037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Comparison Between LIDAR-Based Feedforward and DAC for Control of Wind Turbines","authors":"M. Khaniki, D. Schlipf, P. Cheng","doi":"10.1109/CCTA.2018.8511422","DOIUrl":"https://doi.org/10.1109/CCTA.2018.8511422","url":null,"abstract":"The rotor-effective wind speed is the main disturbance for wind turbine collective pitch controller. On the one hand, Lidar-Systems provide good estimates of this wind speed and thus lidar-assisted feedforward control (LAC) is very promising to reduce structural loads. On the other hand, several pseudo-feedforward controller such as the Disturbance Accommodating Control (DAC) have been proposed, which are based on an estimate of the rotor-effective wind speed from turbine signals and thus avoid the additional cost of a lidar system. This study compares both concepts for overrated wind speed using low-order linear models to investigate the fundamental differences. Results show that DAC without considering pitch actuator dynamics can obtain comparable results with the LAC due to the measurement uncertainty of the lidar-measurement. When pitch actuator dynamics are included in the simulation, the LAC results are not impacted, since the wind speed estimation is provided with some preview. However, the results of DAC including pitch actuator dynamics are impacted significantly and cannot reach the benefit of LAC.","PeriodicalId":358360,"journal":{"name":"2018 IEEE Conference on Control Technology and Applications (CCTA)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129906168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A 3D Reactive Collision Avoidance Algorithm for Nonholonomic Vehicles","authors":"M. Wiig, K. Pettersen, T. R. Krogstad","doi":"10.1109/CCTA.2018.8511437","DOIUrl":"https://doi.org/10.1109/CCTA.2018.8511437","url":null,"abstract":"This paper presents a 3D reactive collision avoidance algorithm for vehicles with nonholonomic constraints. The algorithm steers the heading and pitch angle of the vehicle in order to maintain a constant avoidance angle to the obstacle, thus ensuring a safe collision avoidance maneuver. The flexibility provided by moving in three dimensions is utilized by choosing an optimal pair of safe pitch and heading angles for avoidance. Furthermore, the algorithm incorporates limits on the allowed pitch angle, which are often present in practical scenarios. The collision avoidance property is mathematically proved, and the analysis is validated by several numerical simulations.","PeriodicalId":358360,"journal":{"name":"2018 IEEE Conference on Control Technology and Applications (CCTA)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126669551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Increasing Computational Speed of Nonlinear Model Predictive Control Using Analytic Gradients of the Explicit Integration Scheme with Application to Collision Imminent Steering","authors":"J. Wurts, J. Stein, Tulga Ersal","doi":"10.1109/CCTA.2018.8511613","DOIUrl":"https://doi.org/10.1109/CCTA.2018.8511613","url":null,"abstract":"In previous work, a collision imminent steering algorithm using nonlinear model predictive control (MPC) was developed for high speed applications where emergency maneuvers can bring the vehicle to its limits of handling. By exploiting the vehicle dynamics, the algorithm was shown in simulation to successfully perform a lane change maneuver in the shortest distance possible. However, it was unable to achieve realtime performance due to the computational expense in solving the underlying nonlinear optimization problem. To reduce the solution time, analytic derivatives of the trajectory simulation are derived in this paper, improving the gradient computation time and gradient accuracy. It is shown through examples that the analytic derivatives are an order of magnitude faster than finite differences, and the improved accuracy reduces the number of iterations required in the nonlinear gradient-based optimization by around 20%.","PeriodicalId":358360,"journal":{"name":"2018 IEEE Conference on Control Technology and Applications (CCTA)","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130616411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Performance Comparison of Optimised and Non-Optimised Yaw Control for a Multi Rotor System","authors":"Euan MacMahon, W. Leithead","doi":"10.1109/CCTA.2018.8511353","DOIUrl":"https://doi.org/10.1109/CCTA.2018.8511353","url":null,"abstract":"This paper presents an optimised yaw algorithm for the novel yaw system whereby the thrust of individual rotors of a Multi Rotor System (MRS) are varied in order achieve yaw torque. The control system is built upon a previous paper where a non-optimised yaw algorithm is shown to be capable of providing stable yaw control for an MRS. The optimised yaw algorithm provides increased energy capture and improved performance compared to that of the non-optimised system. The MRS model is also developed further from the previous paper which simplifies the MRS by clustering together groups of rotor and power conversion (RPC) systems. All 45 RPC systems are modelled to more accurately represent the MRS and to allow feedback from each RPC system. Both an estimated wind speed and system of flags are fed back to the optimised yaw algorithm to calculate the RPC systems with greatest potential change in yaw torque and to ensure that each RPC system does not operate outside a defined safe operational envelope. The performance of the energy capture for the optimised yaw controller is analysed and compared to the basic non-optimised controller. The optimised controller shows improved yaw control at each wind speed. The reduction in energy capture for the non-optimised controller is 0.61 %, 1.9% and 0.89% of the total energy captured for 8m/s, 11m/s and 15m/s respectively. This compares to 0.45%, 0.67% and 0.66% for the optimised controller.","PeriodicalId":358360,"journal":{"name":"2018 IEEE Conference on Control Technology and Applications (CCTA)","volume":"29 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123500349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}