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Online Estimation (online + estimation)
Selected AbstractsOnline estimation and control of polymer quality in a copolymerization reactorAICHE JOURNAL, Issue 5 2002Myung-June Park The validity of an online state estimator for a semi-batch MMA/MA solution copolymerization reactor was established using online densitometer and viscometer. Using the conventional extended Kalman filter (EKF) as the state estimator, the experiment was conducted under both isothermal and nonisothermal conditions for application to the control of copolymer properties. Further analysis was made by using ofline measurement data for the mol fraction of MMA in the remaining monomers and the solid content. The EKF was found to provide a good estimate for the state of the copolymerization system. A model predictive controller was designed and implemented to obtain copolymers with uniform copolymer composition and the desired weight average molecular weight by adopting the feed flow rate of MMA and the reaction temperature as control inputs. The controller was proven effective with a satisfactory performance for the control of polymer properties in the semi-batch copolymerization reactor. [source] Compensation of actuator delay and dynamics for real-time hybrid structural simulationEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 1 2008M. Ahmadizadeh Abstract Compensation of delay and dynamic response of servo-hydraulic actuators is critical for stability and accuracy of hybrid experimental and numerical simulations of seismic response of structures. In this study, current procedures for compensation of actuator delay are examined and improved procedures are proposed to minimize experimental errors. The new procedures require little or no a priori information about the behavior of the test specimen or the input excitation. First, a simple approach is introduced for rapid online estimation of system delay and actuator command gain, thus capturing the variability of system response through a simulation. Second, an extrapolation procedure for delay compensation, based on the same kinematics equations used in numerical integration procedures is examined. Simulations using the proposed procedures indicate a reduction in high-frequency noise in force measurements that can minimize the excitation of high-frequency modes. To further verify the effectiveness of the compensation procedures, the artificial energy added to a hybrid simulation as a result of actuator tracking errors is measured and used for demonstrating the improved accuracy in the simulations. Copyright © 2007 John Wiley & Sons, Ltd. [source] Adaptive model predictive control for co-ordination of compression and friction brakes in heavy duty vehiclesINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 10 2006Ardalan Vahidi Abstract In this paper, an adaptive model predictive control scheme is designed for speed control of heavy vehicles. The controller co-ordinates use of compression brakes and friction brakes on downhill slopes. Moreover, the model predictive controller takes the actuator constraints into account. A recursive least square scheme with forgetting is used in parallel with the controller to update the estimates of vehicle mass and road grade. The adaptation improved the model predictive controller. Also online estimation of the road grade enhanced the closed-loop performance further by contributing through feedforward control. Simulations of realistic driving scenarios with a validated longitudinal vehicle model are used throughout this paper to illustrate the benefits of co-ordinating the two braking mechanisms and influence of unknown vehicle mass and road grade. Copyright © 2006 John Wiley & Sons, Ltd. [source] A dynamic bandwidth resource allocation based on neural networks in euroskyway multimedia satellite systemINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 1 2003P. Camarda Abstract Advanced traffic management based on the dynamic resource assignment allows a broadband satellite system such as euroskyway (ESW) to dynamically assign the resources of connections. The mechanisms of the dynamic assignment exploit variations of burstiness exhibited by real time and non-real time variable bit rate traffic sources to perform an optimized resource redistribution. The efficiency of the dynamic bandwidth allocation capability (DBAC) depends on the accuracy of the traffic source description; inaccurate assessment of the arrival process will cause an overhead and a degraded utilisation of system resources. In this paper a flexible traffic burstiness predictor for dynamic bandwidth resource allocation based on neural network is presented. The approach is able to perform an online estimation of expected resource requests implementing traffic resource assignment by using a sub-symbolic adaptive representation of the traffic source. The achieved results prove that the flexible approach is more effective than the ones based on fixed schemes designed using analytical traffic source description when applied on the satellite terminal ESW system component. Copyright © 2003 John Wiley & Sons, Ltd. [source] Autonomous excavation using a rope shovelJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 6-7 2006Matthew Dunbabin This paper describes the development of a system to automate the digging cycle of an electric rope shovel, a machine which is widely used in open-pit mining. Achieving optimal digging performance requires path planning strategies to ensure dipper (bucket) filling, as well as methods to detect when to disengage the dipper from the bank. To this end, techniques to detect and avert dipper stall, and the online estimation of dipper "full-ness," are described along with in-field experimental results using a one-seventh scale-model electric rope shovel. Over 100 autonomous excavation cycles, in a variety of digging conditions, resulted in cycle times consistent with a human operator, but with lower overall motor loading. © 2006 Wiley Periodicals, Inc. [source] | ||||||||||