Simon Hecker

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We describe recent developments and enhancements of the LFR-toolbox for MATLAB for building LFT-based uncertainty models. A major development is the new LFT-object definition supporting a large class of uncertainty descriptions: continuous- and discrete-time uncertain models, regular and singular parametric expressions, more general uncertainty blocks(More)
Symbolic preprocessing techniques are very useful to obtain low order LFT-representations for parametric models. In this paper we give an overview about existing preprocessing methods and we present new techniques and enhancements of existing methods. All methods are implemented in the new version 2 of the LFR-toolbox and their capabilities are illustrated(More)
We present a general approach to generate a linear parametric state-space model, which approximates a nonlinear system with high accuracy. It is optimally suited for LFT-based robust stability analysis and control design. At the beginning a Jacobian-based linearization is applied to generate a set of linearized state-space systems describing the local(More)
In this paper we extend earlier results on Invariance Control to the special class of nonlinear control input affine systems with relative degree two. A switching strategy for control parameters and an easy to calculate invariance region together form an intelligent switching Invariance Controller, achieving asymptotic stability for the controlled dynamics(More)
The paper presents a general procedure to approximate a parametric Linear Fractional Representation (LFR) with a reduced order LFR. The error resulting from a multidimensional model reduction step is covered by an unstructured uncertainty and the reduced order LFR is further optimized such that the norm of the required unstructured uncertainty is minimized.(More)
  • Simon Hecker
  • 2006 IEEE Conference on Computer Aided Control…
  • 2006
Two vehicle steering controllers to improve the yaw dynamics of a mid-size passenger car are designed based on robust H<inf>&#x221E;</inf> synthesis techniques. The controllers fulfill the desired mixed-sensitivity performance specifications robustly with respect to large uncertainties in the vehicle model parameters for longitudinal speed, road adhesion,(More)
The paper presents an example of a linear, parameter varying (LPV) controller synthesis for a generic nonlinear missile. It is based on obtaining a parameter dependent Ljapunov function, in order to ensure stability of the system. The LPV model of the missile is constructed by means of Jacobian linearization at fixed parameter values. Performance(More)
We present a simulation based software environment conceived to allow an easy assessment of fault diagnosis based fault tolerant control techniques. The new tool is primary intended for the development of advanced flight control applications with fault accommodation abilities, where the requirements for increased autonomy and safety play a premier role.
Active engine mounts make an important contribution to ensure the comfort in vehicles with emission-reducing engine technologies, e.g., cylinder-on-demand (COD). To control active engine mounts either adaptive filtering or map-based feedforward control is commonly employed. This contribution proposes two methods to combine both control strategies in order(More)