No abstract

No abstract

This paper discusses thermodynamic models of air inside pneumatic actuator chambers. In servo-pneumatics common practice, these models are simplified by neglecting the temperature dynamics. Classical models in the literature assume the temperature inside the pneumatic chamber either to be constant or to follow a polytropic law. Furthermore, the mixing process of air entering the chamber and heat transfer between air and cylinder walls is often neglected or only implicitly taken into account.This work evaluates the impact of these simplifications and order reductions in the prediction of pressure inside the actuator chamber. Classical models are compared with several others not only taking into account the mixing process but also explicitly including the heat transfer between air and cylinder walls. Simulation studies show that the reduced-order models proposed in this paper can lead to a mean square error in pressure prediction of only 10 per cent of that obtained using classical models.Keywords: servo-pneumatic systems modelling, servo-pneumatic systems simulation INTRODUCTIONis to neglect temperature dynamics and to consider a polytropic process with an index ranging from In order to control a pneumatic actuator accurately, a 1 (isothermal process) to 1.4 (adiabatic reversible model of the pneumatic system has to be established. process). [7][8][9][10] where, although the pressure is inappropriate for control purposes since it is dynamic model is deduced assuming that the temmathematically difficult to handle and demands a perature follows a polytropic law, a further simplifimass or temperature observer as these variables cation in this model is introduced by neglecting cannot be correctly measured during operation.temperature changes with respect to ambient temServo-pneumatic systems are used in applications perature. This approach leads to a situation where where force or motion control is required. In both the polytropic index of pressure dynamics is tuneable situations the pressure inside the chambers is the but the temperature is fixed at ambient temperature. most relevant thermodynamic state variable since More recently, a new approximate model of a the control goals directly depend on it. Therefore, the pneumatic cylinder thermodynamic chamber was most typical solution to reduce the order of the model proposed in reference [11]; based on experimental evidence presented in reference [12], Richer and Hurmuzlu [11] use a polytropic-based model whose

Occupant behaviour and their interactions with building systems could significantly influence energy consumption in buildings. Studies suggest "default setting" techniques could be used as intervention strategies as people's preferences are dramatically influenced by minor variations in settings. With the goal to reduce lighting-related energy consumption, we study the effects of default lighting settings on occupants' rate of lighting adjustments in a single occupancy office space. Through the use of immersive virtual environments, we analysed 160 participants' data in a virtual office space. Based on the results, people are significantly more likely to keep the lighting settings if the default condition had some or maximum daylighting available. Additionally, the participants reading speed and comprehension were respectively faster and more accurate in conditions where simulated daylight was available. By using default settings, we can influence occupant behaviour towards more energy efficient choices in their daily interactions with building's lighting and shading systems.

No abstract

The use of pneumatic devices is widespread among different industrial fields, in tasks like handling or assembly. Pneumatic systems are low-cost, reliable, and compact solutions. However, its use is typically restricted to simple tasks due to the poor performance achieved in applications where accurate motion control is required. This paper presents a novel nonlinear controller, using neural network-based models, that allows the use of common industrial servopneumatic components in applications where fine trajectory following tasks is required. Furthermore, several experimental trials show that the system is highly robust to payload variation without any controller retuning. These results encourage the use of pneumatics actuators in a set of applications for which they have not been traditionally considered.

The use of pneumatic devices is widespread among different industrial fields, in tasks like handling or assembly. Pneumatic systems are low-cost, reliable, and compact solutions. However, its use is typically restricted to simple tasks due to the poor performance achieved in applications where accurate motion control is required. One of the key elements required to achieve a good control performance is the model of the servopneumatic system. An accurate model may be of vital importance not only in the simulation steps needed to test the control strategy but also as a part of the controller itself. This work presents a new servopneumatic system model primarily developed for control tasks, namely, to predict pneumatic and friction forces in dynamic tests. The model can also be used in simulation tasks to predict the piston position and velocity. The performance on both applications is validated experimentally.

No abstract