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In this paper, the operating states of a wheel loader were studied for diagnostics purposes using a real time simulation model of an articulated-frame-steered wheel loader. Test drives were carried out to obtain measurement data, which were then analyzed. The measured time series data were analyzed to find the sequences of operating states using two different data sets, namely the variables of hydrostatic transmission and working hydraulics. A time series is defined as a collection of observations made sequentially in time. In our proposed method, the time series data were first segmented to find operating states. One or more segments build up an operating state. A state is defined as a combination of the patterns of the selected variables. The segments were then clustered and classified. The operating states were further analyzed using the quantization error method to detect anomalies.

Electronically controlled automatic hydraulic bucket stabilizer system is considered as an example case while researching how suitable a typical proportional mobile valve is for fast control applications. A verified simulation model, including hydraulics, mechanics, and electronics is used for developing the stabilizer system. The most suitable type and size for the spool of the valve is found out with help of the simulation model. The simulation model is also used for discovering system characteristics, and thereby improving control algorithms. Simulated results for different type of spools are introduced. Also, effects of the most critical characteristics of the valve are enclosed.

The goal of the paper is to study the properties of a teleoperated mobile machine by means of simulation model of the system and measurements. In this paper some parts of the prototype of the teleoperated machine and the verification results of simulation model of the mobile machine are introduced. The challenge in teleoperation is to have a smooth and accurate control of the machine, because the operator can not feel any force feedback. The machine is valve controlled and the influence of different types of valves is significant for the control of the machine. In this paper is studied via simulation model different kind of valve solutions such as different spool types and effect of pressure compensator among others. The goal in future is to have a totally autonomous mobile machine and it needs more research and development work. With simulation model of the machine it is possible to test new components and hydraulic solutions for power transmission of the mobile machine.