Universität des Saarlandes
Mechatronik
A fault-tolerant control method based on algebraic derivative estimation is introduced. It is applied on an electromagnetically supported plate as an example of a nonlinear and an open-loop unstable system. The design of the closed loop... more
A fault-tolerant control method based on algebraic derivative estimation is introduced. It is applied on an electromagnetically supported plate as an example of a nonlinear and an open-loop unstable system. The design of the closed loop control is facilitated assuming that relevant faults are identified sufficiently precisely and fast. This is justified by a novel robust model-based fault identification scheme which relies on algebraic methods for numerical differentiation. Derivative estimation parameters and fault-detection thresholds are chosen systematically based on the properties of the measurements. The experimental results show the practical usefulness of the presented methods.
A plate that may freely move in the field of four electromagnets is automatically controlled such as to keep a ping-pong ball bouncing. A simple mathematical model of the process is used together with an algebraic derivative estimator in... more
A plate that may freely move in the field of four electromagnets is automatically controlled such as to keep a ping-pong ball bouncing. A simple mathematical model of the process is used together with an algebraic derivative estimator in order to estimate the impact times of the ball. This information is used to predict the next impact. The only measurement used in this process is the plate position measurement. It is related with the reference forces in order to generate a motion appropriate to keep the ball bouncing. Precision and robustness against measurement noise, mechanical vibrations, and fast motions of the plate are achieved by a suitable parameterization of the algebraic derivative estimator and an automatic calibration. Experimental results are shown.
- by Lothar Kiltz and +2
- •
- Algebra, Vibrations, Estimation Theory, Robots
A nonlinear mathematical model for the dynamics of permanent magnet synchronous machines with interior magnets is discussed. The model of the current dynamics captures saturation and dependency on the rotor angle. Based on the model, a... more
A nonlinear mathematical model for the dynamics of permanent magnet synchronous machines with interior magnets is discussed. The model of the current dynamics captures saturation and dependency on the rotor angle. Based on the model, a flatness-based field-oriented closed-loop controller and a feed-forward compensation of torque ripples are derived. Effectiveness and robustness of the proposed algorithms are demonstrated by simulation results.
A nonlinear mathematical model for the dynamics of permanent magnet synchronous machines with interior magnets is discussed. The model of the current dynamics captures saturation and dependency on the rotor angle. Based on the model, a... more
A nonlinear mathematical model for the dynamics of permanent magnet synchronous machines with interior magnets is discussed. The model of the current dynamics captures saturation and dependency on the rotor angle. Based on the model, a flatness-based field-oriented closed-loop controller and a feed-forward compensation of torque ripples are derived. Effectiveness and robustness of the proposed algorithms are demonstrated by simulation results.
Abstract—A model-based online fault-diagnosis scheme for an electromagnetically supported plate is presented as an example of a nonlinear and open-loop unstable system. First, residuals for sensor as well as for actuator faults are... more
Abstract—A model-based online fault-diagnosis scheme for an electromagnetically supported plate is presented as an example of a nonlinear and open-loop unstable system. First, residuals for sensor as well as for actuator faults are generated using algebraic derivative estimators. Then, the robust detection and isolation of step-like sensor and actuator faults is presented. The performance of the proposed algorithms is illustrated by experimental results. Index Terms—Diagnosis, Derivative estimation, Change detec-tion.
- by Lothar Kiltz and +1
- •
- Engineering
A fault-tolerant control method based on algebraic derivative estimation is introduced. It is applied on an electromagnetically supported plate as an example of a nonlinear and an open-loop unstable system. The design of the closed loop... more
A fault-tolerant control method based on algebraic derivative estimation is introduced. It is applied on an electromagnetically supported plate as an example of a nonlinear and an open-loop unstable system. The design of the closed loop control is facilitated assuming that relevant faults are identified sufficiently precisely and fast. This is justified by a novel robust model-based fault identification scheme which relies on algebraic methods for numerical differentiation. Derivative estimation parameters and fault-detection thresholds are chosen systematically based on the properties of the measurements. The experimental results show the practical usefulness of the presented methods.
A plate that may freely move in the field of four electromagnets is automatically controlled such as to keep a ping-pong ball bouncing. A simple mathematical model of the process is used together with an algebraic derivative estimator in... more
A plate that may freely move in the field of four electromagnets is automatically controlled such as to keep a ping-pong ball bouncing. A simple mathematical model of the process is used together with an algebraic derivative estimator in order to estimate the impact times of the ball. This information is used to predict the next impact. The only measurement used in this process is the plate position measurement. It is related with the reference forces in order to generate a motion appropriate to keep the ball bouncing. Precision and robustness against measurement noise, mechanical vibrations, and fast motions of the plate are achieved by a suitable parameterization of the algebraic derivative estimator and an automatic calibration. Experimental results are shown.
- by Lothar Kiltz and +1
- •
- Algebra, Vibrations, Estimation Theory, Robots
Algebraic derivative estimators are linear time-invariant filters for approximating numerical derivatives of measured signals in real-time. Since they are robust to measurement noise, algebraic derivative estimators may simplify a wide... more
Algebraic derivative estimators are linear time-invariant filters for approximating numerical derivatives of measured signals in real-time. Since they are robust to measurement noise, algebraic derivative estimators may simplify a wide variety of practical control engineering tasks, as this thesis demonstrates through numerous examples and an extensive experimental case study. The selection of favorable filter parameters is a key challenge in the application of these estimators. To this end, parameter selection criteria are derived based on approximation theory fundamentals and filter performance in the frequency and time domains. As efficient real-time implementation of these methods is of great practical interest, various techniques to reduce estimation delay and computational effort are discussed.
- by Lothar Kiltz
- •
A nonlinear mathematical model for the dynamics of permanent magnet synchronous machines with interior magnets is discussed. The model of the current dynamics captures saturation and dependency on the rotor angle. Based on the model, a... more
A nonlinear mathematical model for the dynamics of permanent magnet synchronous machines with interior magnets is discussed. The model of the current dynamics captures saturation and dependency on the rotor angle. Based on the model, a flatness-based field-oriented closed-loop controller and a feed-forward compensation of torque ripples are derived. Effectiveness and robustness of the proposed algorithms are demonstrated by simulation results.