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In this paper, the performance of a particular state observer algorithm is investigated for concurrently estimating the state of charge of a Li-Ion battery and the deviation of characteristic parameters from their initial values in order to diagnose the aging behavior of the system. The estimation is based on an online minimization approach that has been chosen in particular due to the significant...
An approach for an adaptive position-dependent friction estimation for linear electromagnetic actuators with altered characteristics is proposed in this paper. The objective is to obtain a friction model that can be used to describe different stages of aging of magnetic actuators. It is compared to a classical Stribeck friction model by means of model fit, sensitivity, and parameter correlation. The...
The use of random matrices for tracking extended objects has received high attention in recent years. It is an efficient approach for tracking objects that give rise to more than one measurement per time step. In this paper, the concept of random matrices is used to track surface vessels using highresolution automotive radar sensors. Since the radar also receives a large number of clutter measurements...
The improvement of collision avoidance for vessels in close range encounter situations is an important topic for maritime traffic safety. Typical approaches generate evasive trajectories or optimise the trajectories of all involved vessels. The idea of this work is to validate these trajectories related to guaranteed motion safety, which means that it is not sufficient for a trajectory to be collision-free,...
In this paper a manoeuvre based identification process and parameter analysis of a small unmanned surface vehicle (USV) is described. The objective is to identify unknown hydrodynamic and propulsion parameters in one step by means of a series of different manoeuvres. Methods on the basis of the Fisher information matrix are used for the quality analysis of the parameter estimates. Furthermore, a process...
Knowing the position of the spool in a solenoid valve, without using costly position sensors, is of considerable interest in a lot of industrial applications. In this paper, the problem of position estimation based on state observers for fast-switching solenoids, with sole use of simple voltage and current measurements, is investigated. Due to the short spool traveling time in fast-switching valves,...
In this paper an approach towards databased fault diagnosis of linear electromagnetic actuators is presented. Time and time-frequency-domain methods were applied to extract fault related features from current and voltage measurements. The resulting features were transformed to enhance class separability using either Principal Component Analysis (PCA) or Optimal Transformation. Feature selection and...
Small vessels or unmanned surface vehicles only have a limited amount of space and energy available. If these vessels require an active sensing collision avoidance system it is often not possible to mount large sensor systems like X-Band radars. Thus, in this paper an energy efficient automotive radar and a laser range sensor are evaluated for tracking surrounding vessels. For these targets, those...
In this paper a semilinear parabolic PDE for the control of solenoid valves is presented. The distributed parameter model of the cylinder becomes nonlinear by the inclusion of saturation effects due to the material's B/H-curve. A flatness based solution of the semilinear PDE is shown as well as a convergence proof of its series solution. By numerical simulation results the adaptability of the approach...
In this paper, an approach for a collision avoidance system for small Unmanned Surface Vehicles (USV) is presented. These kind of USVs are typically used for measuring tasks and thus, the collision avoidance algorithm has to take the mission objective and information about obstacles and other vessels into account. It generates an evasive trajectory that either leads around the obstacle, reduces the...
In this work an approach to generate collisions-free trajectories for vessels is presented. The approach consist of a global path planner and a local evasive trajectory planner. The global path planner uses chart information from ENCs to estimate waypoints for a global path avoiding obstacles defined in a chart. The local evasive trajectory planner uses information of a target tracking system to proof...
Tracking overtaking vehicles is an integral aspect of Lane Change Assistant Systems. For this, in this work, a set of six radar sensors is mounted on a test vehicle. As the sensors generate spatially extended measurements from different parts of the vehicles, the estimation of position and velocity of the surrounding vehicles leads to an extended target tracking problem. This is especially the case...
In this paper, a control strategy that enables a reliable dip detection for solenoid valves is presented. For this purpose, the power electronics components are temporarily switched into a linear mode, using a power MOSFET as a voltage controlled resistor. The voltage is stabilized via a nonlinear controller that has been designed using Lyapunov's direct method. The stability region is determined...
In this paper, a number of new results are presented that have been achieved with a previously suggested approach for estimating the armature position of electro-magnetic actuators. With the assumption that only current and voltage measurements are available, a discrete time model reference adaptive system (MRAS) is used. It is shown that by identification of the parameters of the electrical subsystem,...
This paper studies state estimation for a dual coil solenoid valve, based on a nonlinear Sliding-Mode-Observer (NLSMO). A simple model of the solenoid is presented that might be applied for different types of electromagnetic actuators. Solely current and voltage measurement is used to observe the position trajectory of the moving armature. By simulation, it is shown that the states can be reconstructed...
This paper addresses the problem of navigation algorithms in the context of high accuracy motion control for a unmanned surface crafts. The effectiveness of an unscented Kalman filter algorithm in combination with a detailed nonlinear 3DOF dynamical model for motion estimation is shown. Water currents are regarded as slowly varying parameters estimated by the filter which has been augmented by two...
This paper presents a method to efficiently solve the control allocation problem of vessels propelled by two azimuth thrusters with limited panning range. The use of rotatable thrusters results in a configuration matrix that, in the context of control allocation, typically leads to a constrained nonlinear optimization problem. It is shown, how this can be transformed into an easy to solve scalar unconstrained...
In this paper, the use of a discrete time model reference adaptive approach is proposed for estimating the armature position of electro-magnetic actuators. It is assumed that current and voltage measurements are available, only. It is shown that by identification of the parameters of the electrical subsystem, a unique and accurate estimate for the armature position can be obtained. To this end two...
This paper studies the problem of computing feedforward control input signals for a solenoid actuator based on a distributed parameter model. The solution is expressed as a power series, and a backward/forward procedure is suggested to verify the approach and to investigate the effect of simplifications. Experimental results from a lab test rig are provided to show that this approach can provide feed-forward...
This paper describes the control aspects and results of a student project called “MonoChair”. The goal was to have students walk through a complete control systems development cycle. The focus in this contribution is put on the design of a stabilizing linear controller, a sensitivity analysis in order to study the impact of parameter variations, and the design and test of an adaptive controller using...
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