In vibration therapy, mechanical vibrations are induced in the body while the person sits upright on a high frequency vibrating platform. Multiple meta-analyzes have shown growing interest in this type of therapy, not only to fortify muscles, for the prevention and treatment of bone decalcification (osteoporosis), but also for patients suffering from certain chronic diseases [1]. The vibrations of the platform are specific for each patient because the frequency and amplitude of the oscillations are directly related to the person's weight. The original system, which was patented [7], was an electromechanical one with limited possibilities for further research. This paper presents a low frequency electromagnetic actuated vibrating platform and the corresponding electronic control system which automatically corrects the vibrations frequency through a feedback loop. Frequency stability in this case is ± 0.5 Hz.

The paper presents the hardware structure of an original hydraulic positioning system based on a mechatronic approach. Dedicated control algorithms are also presented.

Abstract. In driving systems using working fluids, for monitoring the fluid's parameters such as pressure, flow and temperature appropriate transducers are present in different areas of the system. Such an approach has certain disadvantages with regard to the installation and powering of the transducers as well as the transmission of the signals supplied by the transducers to the system's electronics command block. Both hydraulic and pneumatic driving systems are considered. The paper proposes a sensor block which integrates the above mentioned sensors and eliminates the previously outlined disadvantages. The proposed block can be designed for an easy installation in a driving system containing a pneumatic linear motor; basically for a standardised motor one of the caps is replaced with the proposed block. An example is also shown for the integration of the proposed block in the structure of a pneutronic system.

Abstract. The paper presents a linear pneumatic actuator with short working stroke. It consists of a pneumatic motor (a simple stroke cylinder or a membrane chamber), two 2/2 pneumatic distributors "all or nothing" electrically commanded for controlling the intake/outtake flow to/from the active chamber of the motor, a position transducer and a microcontroller. There is also presented the theoretical analysis (mathematical modelling and numerical simulation) accomplished.

Various constructive versions of hydraulic units found in the structure of proportional hydraulic equipment are analysed in the paper. For each version, the authors establish the variation law of the flow section in function of the position of the adjusting element in relation to the reference position. The approach is useful when a theoretical analysis of a proportional equipment is needed, as well as when the characteristic diagrams of the equipment are theoretically established.