The paper presents an experimental analysis of the selected feedback vibration control schemes dedicated to magnetorheological dampers, related to ride comfort and road holding. They were applied in a complex vibration control system installed in a commercially available off-road vehicle. Original shock-absorbers of the vehicle were replaced with magnetorheological dampers. The control system takes advantage of numerous sensors installed in the vehicle tracking its motion, i.e. accelerometers, suspension deflection sensors (linear variable differential transformer) and IMU module. Vibration control algorithms: Skyhook, PI, and Groundhook were tested experimentally using mechanical exciters adapted for diagnosis of a vehicle suspension system. Since the presented semi-active vibration control requires the magnetorheological damper inverse model to be applied, accurate operation of this model significantly influences the quality of vibration control. Therefore, additional analysis was related to application of measurements from accelerometers or suspension deflection sensors in the inverse model. Presented variants of control algorithms were compared by means of transmissibility characteristics evaluated in the frequency domain as well as using ride-comfort-and drivingsafety-related quality indices. It was confirmed that the Skyhook control as well as PI improved ride comfort, whereas Groundhook control improved road holding and decreases vibration of the wheels. Furthermore, it was shown that both approaches to the relative velocity estimation, based on accelerometers and linear variable differential transformers, can be used in this application. However, the first solution gives better results in the case of the Skyhook and PI control, whereas application of LVDT sensors is better for the Groundhook algorithm.

According to recent findings, it is possible to computationally determine a measurement result (value and uncertainty), using a special measurement method, in which this uncertainty is less than that assessed directly from experiments using Type B evaluation. The method works well only if the quantity is additive and its uncertainty is constant, i.e. independent of the measurement value. In the paper, a generalisation is made that also allows for the application of similar reasoning to quantities with variable uncertainties. The generalisation is obtained thanks to the replacement of the least squares optimisation, used in the derivation of the first method, with the weighted least squares. Examples with models of quantities that have variable uncertainties are described to show circumstances where improvements are significant. It can be said that the method described always improves uncertainties of additive quantities, but the improvement is not always significant. Suggestions to obtain the best improvement are given according to the analysis performed. A real laboratory experiment of a resistance measurement, with its uncertainty dominated by current measurement, was conducted to show how the method works.

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This paper describes a way of determining selected water parameters using a prototype of a remote-controlled catamaran. The remote controlling allows to steer the boat and to manage the measurement process from the shore. It is possible to monitor the water parameters online as well as to store them and analyze them afterwards. The measured parameters are determined mainly using potentiometric methods and include several ion concentrations. The system is orientated towards monitoring breeding ponds or other similar surface waters. The mechanical construction of the catamaran, its electronic circuits and implemented software are described in detail in the paper. Conclusions obtained from preliminary tests are also included. The described construction allows analysts to perform simple and inexpensive remote measurements or assessments of water quality and reduces the time of such analysis in comparison to traditional sampling.