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This paper continues the development of an iterative learning control law for a class of spatially distributed systems based on the particular case of a circular deformable mirror. This system is described by a fourth-order partial differential equation but in many cases the design and implementation of control laws is based on a discrete model. In this paper, an unconditionally stable finite difference...
An optimal control problem for heat conduction in a metal bar heated and cooled by two Peltier elements attached to its bottom surface is investigated. The bar has the shape of an elongated cuboid, the vertical sides of which are insulated, whereas the heat exchange with the environment takes place on the upper surface. The problem is to find the time history of the elements' heating powers transferring...
This paper presents a novel approach for an interval-based gain scheduling control design aiming at a guaranteed stabilization of the system dynamics over a predefined time horizon. Due to the goal of asymptotic stability, the design aims at the temporal reduction of the widths of intervals representing worst-case bounds of the system states at a specific point of time. The main idea of the control...
In this contribution, a norm-optimal iterative learning control (NOILC) for the two main axes of a bridge crane is presented. For each axis, the NOILC operates in parallel to a linear-quadratic (LQ) state feedback of the tracking error. Regarding the tracking of repetitive trajectories, the ILC part contributes to a significant reduction of the tracking error from iteration to iteration, up to an...
In many control applications, it is desired to repeat the same control task numerous times with identical reference trajectories. As long as only model inaccuracies and disturbances, which are practically identical for each new execution, appear as external uncertainty, such tasks are well suited for the implementation of learning-type strategies. The fundamental idea of such controllers is not only...
Oscillation attenuation is an essential task for practically any crane application. Classically, such control strategies make use of the actuation of a crane trolley to counteract the motion of a swinging payload. As an alternative to controlling trolley motions, variations of the rope length can be considered. In contrast to scenarios where trolley motions are used to attenuate oscillations, the...
In this paper, a nonlinear control approach is presented for an electro-pneumatic clutch actuator for heavy trucks. A clutch is required at start-up or during gear shifts to disconnect the combustion engine from the gear box. This automated actuator provides the necessary actuation force according to the large torque transmitted through the power train. Based on a control-oriented system representation,...
This contribution presents a robust ILC control design based on guaranteed costs. By combining this ILC design with dynamic feedforward control and an observer-based disturbance compensation, the initial tracking errors in an early learning stage can be reduced. The benefits of the proposed design approach are pointed out at the example of a robust position control of a Permanent Magnet Synchronous...
This paper presents an inversion-based iterative learning control (ILC) for the two main axes of an overhead travelling crane that guarantees both an accurate tracking of repetitive desired trajectories for the crane load and an active damping of crane load oscillations. The main idea of the used ILC algorithm consists in a minimisation of the tracking error by iteratively improved inputs sequences...
In this paper, a cascaded nonlinear control design for the position of a hydraulic servo cylinder is presented that is based on a control-oriented mathematical model of the test rig. The difference pressure is controlled in the inner loop, whereas the position control is addressed in the outer control loop. Additionally, the outer position control loop is extended by a combination of feedforward friction...
In this paper, backstepping control techniques are presented for a mechanism dedicated to accurately reproduce the breathing-induced motion of a human lung tumour. A lung tumour mimic model should perform the same smooth motion as a real one in a human body during inhalation and exhalation. Therefore, a three-dimensional mechanism with three pneumatically driven axes has been developed and built up...
In this paper, a Takagi-Sugeno (TS) approach is proposed for the position control of a hydraulic servo cylinder. Based on a nonlinear mathematical model of the test rig, an exact quasi-linear model with state-dependent matrices is derived and reformulated as a TS fuzzy model. In this framework, the given lower and upper bounds of the nonlinearities are considered by separate local models belonging...
The control of nonlinear dynamic systems is often a challenging task for practical applications if the process model under consideration is significantly influenced by uncertain parameters and bounded (additive) uncertainty and if it has to be guaranteed simultaneously that specific state constraints are not violated. According to previous work, the handling of bounded uncertainty becomes possible...
This paper presents a tracking control approach for a hydrostatic transmission system. To reduce the effort regarding control design and implementation, a decentralised control structure has been investigated in earlier research that outperformed a central one. In this paper, a new cascaded structure is proposed for the decentralised control of the motor angular velocity. For the design of all control...
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...
In this contribution, a model-based tracking control design is proposed for the temperatures at two selected points of a spatially one-dimensional iron rod. The rod is equipped with four Peltier elements on the lower surface, of which the first and the third ones serve as distributed control inputs. For a semi-discretisation of the partial differential equation, the method of integro-differential...
Camless internal combustion engines offer significant improvements over classical ones with cam-driven valves: a better torque performance, an increased fuel economy as well as reduced emissions and pumping losses. The paper presents a nonlinear model for a hydraulic engine valve, which is regulated by an innovative piezo-hydraulic valve spool described by a linear model. Based on these models, a...
In this paper, a model-based control is proposed for an innovative 5 MW wind turbine with a hydrostatic transmission and a synchronous generator. The proposed control is derived by solving Linear Matrix Inequalities (LMIs) so that given parameter uncertainties and state-dependent matrices can be considered adequately. It comprises both a SISO control for the rotor angular velocity by adjusting the...
This paper presents an average value model for the real-time estimation of residual and reaspirative gas in a cylinder of an innovative diesel engine with variable valve lift. Based on a mean-value-model over a combustion cycle, the oxygen mass fraction before the combustion is calculated with information of an oxygen sensor in the intake and a lambda sensor in the exhaust manifold. Furthermore, a...
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