This work presents the development of an ultrasonic system for inspecting adhesive joints, using ... more This work presents the development of an ultrasonic system for inspecting adhesive joints, using the pulse-echo mode. In order to test the proposed system, a real pipe section made with fiberglass reinforced epoxy resin composite, purposely containing disbonds, was provided by PETROBRAS oil company. A mechanical structure embraces the tube, allowing for rotational and translational movements of the transducer along the outer surface of the joint. The ultrasound transducer was coupled to the joint by flowing tap water. Two step motors, one moving linearly and the other moving angularly, were controlled by a specifically developed hardware, which generates the control pulses and the trigger signal to synchronize the ultrasonic emission. The hardware was connected to a PC through an RS-232C interface, and a software was implemented to control the hardware through a based protocol. Ultrasonic pulses are emitted, received and amplified using a pulser/receiver. An A/D converter board was ...
In applications like atomic spectroscopy, cooling atoms or telecommunications is necessary to hav... more In applications like atomic spectroscopy, cooling atoms or telecommunications is necessary to have laser light sources capable of tuning its central emitting frequency over a range of some GHz and a spectral bandwidth in the order of hundreds of kHz. This stabilization presents a demanding control problem, the relation between the instantaneous frequency of emission (1014 Hz) and bandwidth allowed (106 Hz) implies a relative error smaller to 0,01 ppm. The frequency is disturbed by mechanical vibration of the components, electrical noise and variations in the temperature among others. In this work we present the model, identification, design and later evaluation of a system of a close loop control to reject disturbances in the emitted radiation. Is detailed the description of the physical assembly used to stabilize the frequency, the control strategy, the technique to design the robust controllers using H∞ nor-malization and finally the obtained results are evaluated. The obtained re...
This work presents the development of an ultrasonic system for inspecting adhesive joints, using ... more This work presents the development of an ultrasonic system for inspecting adhesive joints, using the pulse-echo mode. In order to test the proposed system, a real pipe section made with fiberglass reinforced epoxy resin composite, purposely containing disbonds, was provided by PETROBRAS oil company. A mechanical structure embraces the tube, allowing for rotational and translational movements of the transducer along the outer surface of the joint. The ultrasound transducer was coupled to the joint by flowing tap water. Two step motors, one moving linearly and the other moving angularly, were controlled by a specifically developed hardware, which generates the control pulses and the trigger signal to synchronize the ultrasonic emission. The hardware was connected to a PC through an RS-232C interface, and a software was implemented to control the hardware through a based protocol. Ultrasonic pulses are emitted, received and amplified using a pulser/receiver. An A/D converter board was ...
In applications like atomic spectroscopy, cooling atoms or telecommunications is necessary to hav... more In applications like atomic spectroscopy, cooling atoms or telecommunications is necessary to have laser light sources capable of tuning its central emitting frequency over a range of some GHz and a spectral bandwidth in the order of hundreds of kHz. This stabilization presents a demanding control problem, the relation between the instantaneous frequency of emission (1014 Hz) and bandwidth allowed (106 Hz) implies a relative error smaller to 0,01 ppm. The frequency is disturbed by mechanical vibration of the components, electrical noise and variations in the temperature among others. In this work we present the model, identification, design and later evaluation of a system of a close loop control to reject disturbances in the emitted radiation. Is detailed the description of the physical assembly used to stabilize the frequency, the control strategy, the technique to design the robust controllers using H∞ nor-malization and finally the obtained results are evaluated. The obtained re...
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