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The dual control problem for an integrator with time-varying gain is reviewed. The neuro-dynamic programming technique of approximate policy iteration is explained. It is shown how a version of this technique, which employs a Gaussian radial basis function network, can be used to calculate a good sub-optimal dual controller for the integrator. This controller performs much better than the certaint
A model for a CSTF with a cell recycle unit was identified in collaboration with Nestlé. Simulations of the model showed that it is possible to control the system in order to concentrate the biomass to 10-13 g/l with an overall dilution rate set to 1 1/h. The bacterium studied was Lactobacillus johnsonii LJ1, which produces lactic acid from lactose. The filter in the cell recycle unit was a cross-
The task of this masters thesis is to investigate the properties of Natural Field Orientation, NFO, a new patented method for controlling the asynchronous motor. The intention is to see whether NFO would make it possible to, in the future, replace the expensive hydraulic motors that are being used in CelsiusTech Electronics' radar directors today with inexpensive hydraulic motors that are bein
Systems with structural resonances are difficult to control if fast responses are required. Rapid changes in the control signal may excite the resonant modes. In digital control with zero-order-hold sampling there will be very rapid changes in the control signal. A way to deal with the problem is to use predictive first-order-hold sampling instead. The control signal is then linear between the sam
Automatic control is increasingly used in mission critical applications. The reason for this is the potential benefits and the fact that control engineering is now able to deal with complex systems. Control of high performance aircrafts is a typical example. Considerable benefits can be obtained by having an aircraft that is unstable in certain flight conditions and providing stability with a cont
Volvo Excavator AB has problems controlling the number of revolutions per second, in the diesel engine of an excavator, when it is running. To solve this problem the different processes controlling the energy flow in an excavator are mathematically identified. These models are later put together to enable simulations of a running excavator on the computer. The different models that need to be iden
