@inproceedings{BraunReuterRudolph,
  author    = {Braun, Tristan and Reuter, Johannes and Rudolph, Joachim},
  title     = {Position observation for proportional solenoid valves by signal injection},
  series = {7th IFAC Symposium on Mechatronic Systems, MECHATRONICS 2016, Loughborough University, Leicestershire, UK, 5—8 September 2016 (IFAC-PapersOnLine Vol. 49, Iss. 21)},
  issn      = {2405-8963},
  doi       = {10.1016/j.ifacol.2016.10.513},
  pages     = {74 -- 79},
  abstract  = {The method of signal injection is investigated for position estimation of proportional solenoid valves. A simple observer is proposed to estimate a position-dependent parameter, i.e. the eddy current resistance, from which the position is calculated analytically. Therefore, the relationship of position and impedance in the case of sinusoidal excitation is accurately described by consideration of classical electrodynamics. The observer approach is compared with a standard identification method, and evaluated by practical experiments on an off-the-shelf proportional solenoid valve.},
  language  = {en}
}
@inproceedings{BraunReuterRudolph,
  author    = {Braun, Tristan and Reuter, Johannes and Rudolph, Joachim},
  title     = {A novel observer approach for self sensing of single-coil digital valves},
  series = {20th World Congress of the International Federation of Automatic Control, (IFAC 2017), 9-14 July 2017, Toulouse, France (IFAC-PapersOnLine Vol. 50, Iss. 1)},
  issn      = {2405-8963},
  doi       = {10.1016/j.ifacol.2017.08.508},
  pages     = {782 -- 787},
  abstract  = {Observer-based self sensing for digital (on-off) single-coil solenoid valves is investigated. Self sensing refers to the case where merely the driving signals used to energize the actuator (voltage and coil current) are available to obtain estimates of both the position and velocity. A novel observer approach for estimating the position and velocity from the driving signals is presented, where the dynamics of the mechanical subsystem can be neglected in the model. Both the effect of eddy currents and saturation effects are taken into account in the observer model. Practical experimental results are shown and the new method is compared with a full-order sliding mode observer.},
  language  = {en}
}
@article{BraunReuterRudolph,
  author    = {Braun, Tristan and Reuter, Johannes and Rudolph, Joachim},
  title     = {Sensorlose Positionsregelung eines hydraulischen Proportional-Wegeventils mittels Signalinjektion},
  series = {at - Automatisierungstechnik},
  volume    = {65},
  number    = {4},
  issn      = {0178-2312},
  doi       = {10.1515/auto-2017-0003},
  pages     = {260 -- 269},
  abstract  = {Es wird eine Methode zur sensorlosen Positionsbestimmung bei elektromagnetisch bet{\"a}tigten Aktoren vorgestellt. Dabei werden basierend auf einer Signalinjektion die positionsabh{\"a}ngigen Parameter bei der injizierten Frequenz bestimmt und daraus {\"u}ber ein geeignetes Modell die Position des Magnetankers ermittelt. Die Eignung des Verfahrens zur sensorlosen Positionsregelung wird an einem bidirektionalen Proportionalventil anhand praktischer Versuche demonstriert.},
  language  = {de}
}
@article{BraunReuterRudolph,
  author    = {Braun, Tristan and Reuter, Johannes and Rudolph, Joachim},
  title     = {Observer Design for Self-Sensing of Solenoid Actuators With Application to Soft Landing},
  series = {IEEE Transactions on Control Systems Technology},
  number    = {Published online: 10 Apr 2018},
  issn      = {1558-0865},
  doi       = {10.1109/TCST.2018.2821656},
  pages     = {8},
  abstract  = {A constructive nonlinear observer design for self-sensing of digital (ON/OFF) single coil electromagnetic actuators is studied. Self-sensing in this context means that solely the available energizing signals, i.e., coil current and driving voltage are used to estimate the position and velocity trajectories of the moving plunger. A nonlinear sliding mode observer is considered, where the stability of the reduced error dynamics is analyzed by the equivalent control method. No simplifications are made regarding magnetic saturation and eddy currents in the underlying dynamical model. The observer gains are constructed by taking into account some generic properties of the systems nonlinearities. Two possible choices of the observer gains are discussed. Furthermore, an observer-based tracking control scheme to achieve sensorless soft landing is considered and its closed-loop stability is studied. Experimental results for observer-based soft landing of a fast-switching solenoid valve under dry conditions are presented to demonstrate the usefulness of the approach.},
  language  = {en}
}
@article{BraunReuterRudolph,
  author    = {Braun, Tristan and Reuter, Johannes and Rudolph, Joachim},
  title     = {A singular perturbation approach to nonlinear observer design with an application to electromagnetic actuators},
  series = {International Journal of Control},
  number    = {Published online: 29 Oct 2018},
  issn      = {1366-5820},
  doi       = {10.1080/00207179.2018.1539873},
  pages     = {14},
  abstract  = {A constructive method for the design of nonlinear observers is discussed. To formulate conditions for the construction of the observer gains, stability results for nonlinear singularly perturbed systems are utilised. The nonlinear observer is designed directly in the given coordinates, where the error dynamics between the plant and the observer becomes singularly perturbed by a high-gain part of the observer injection, and the information of the slow manifold is exploited to construct the observer gains of the reduced-order dynamics. This is in contrast to typical high-gain observer approaches, where the observer gains are chosen such that the nonlinearities are dominated by a linear system. It will be demonstrated that the considered approach is particularly suited for self-sensing electromechanical systems. Two variants of the proposed observer design are illustrated for a nonlinear electromagnetic actuator, where the mechanical quantities, i.e. the position and the velocity, are not measured},
  language  = {en}
}
@inproceedings{BraunReuterRudolph,
  author    = {Braun, Tristan and Reuter, Johannes and Rudolph, Joachim},
  title     = {Flatness-based feed-forward control design for solenoid actuators considering eddy currents},
  series = {Proceedings of the 8th IFAC Symposium on Mechatronic Systems, September 4-6, Vienna, Austria (IFAC-PapersOnLine Vol. 52, Iss. 15)},
  volume    = {52},
  number    = {15},
  publisher = {Elsevier},
  issn      = {2405-8963},
  doi       = {10.1016/j.ifacol.2019.11.736},
  pages     = {567 -- 572},
  abstract  = {Flatness-based feed-forward control of solenoid actuators is considered. For precise motion planning and accurate steering of conventional solenoids, eddy currents cannot be neglected. The system of ordinary differential equations including eddy currents, that describes the nonlinear dynamics of such actuators, is not differentially flat. Thus, a distributed parameter approach based on a diffusion equation is considered, that enables the parametrization of the eddy current by the armature position and its time derivatives. In order to design the feedforward control, the distributed parameter model of the eddy current subsystem is combined with a typical nonlinear lumped parameter model for the electrical and mechanical subsystems of the solenoid. The control design and its application are illustrated by numerical and practical results for an industrial solenoid actuator.},
  language  = {en}
}