In this paper, an idea to comprise a sensor-embedded hydraulic cylinder for offshore applications was suggested. The idea not only includes a scale processing method of piston rod using ceramic plasma coating by Ti-ceramic and Al-ceramic, but also includes a remote detecting method using two sets of optical sensors and optical fibers. And it includes exclusive developing methods of circuit elements for the embedded sensor amplifier. Based on the methods mentioned above, a practical sensor-embedded hydraulic cylinder was developed and several experiments were executed in order to verifying the effectiveness of the suggested method.
There are two main advantages of the developed sensor-embedded hydraulic cylinder. One is that the embedded sensor can detect the piston rod strokes without time delay because light is used as a detecting medium, and it can be adapted to detect instantaneous high speed strokes of piston rod owing to the surge pressure of hydraulic oil. The other advantage is that the embedded sensor is robust against vibrations and shocks during operations, by installing only optical fiber head on the cylinder.
In this paper, a position tuning control method was also discussed, in order to control the positions of multiple cylinders for high power and high precision hydraulic control systems. The discussed method is to comprise a tuning controller based on CPU in view of digital hardware and software. To verify the effectiveness of the discussed method, computer simulations were executed by using two different mathematical models as hydraulic cylinder models. According to the simulation results, the discussed tuning control method was turned out to generate differential tuning control signals accurately. It is expected that the discussed method will be used more effectively than the conventional mechanical tuning control methods in view of accuracy and price burden.
A further study will be concentrated on experiments to analyze the control performance quantitatively for a practical system which is combined the suggested sensor-embedded hydraulic cylinders with the discussed position tuning controller.