Underwater propelling apparatus which stably carries out a propelling operation and a steering operation

An underwater propelling apparatus, comprising:

• a body having a rear side and a forward side;
• a first vibrating unit located on the rear side of said body comprising a first vibrator that is vibrated by reciprocating rotation of a first rotation shaft and a second vibrator that is vibrated by reciprocating rotation of a second rotation shaft, said first vibrator and said second vibrator being arranged in series;
• a second vibrating unit located on the rear side of said body and parallel with said first vibrating unit in a horizontal direction and comprising a third vibrator that is vibrated by reciprocating rotation of a third rotation shaft and a fourth vibrator that is vibrated by reciprocating rotation of a fourth rotation shaft, said third vibrator and said fourth vibrator being arranged in series;
• first to fourth actuators to rotate said first to fourth rotation shafts, respectively;
• a vibrator command generator to output a control signal to set respective amplitudes, frequencies and vibration centers of said first to fourth vibrators associated with the reciprocating rotation of said first to fourth rotation shafts and phases between said first to fourth vibrators to control said first to fourth rotation shafts jointly and respectively;
• and
• an angular servo driver to generate signals to control said first to fourth actuators, respectively, on the basis of a control signal;
• wherein each of said first to fourth vibrators is elastic, said second vibrator, positioned rearwardly of said first vibrator with respect to said body, has a higher elastic modulus than said first vibrator, and said fourth vibrator, positioned rearwardly of said third vibrator with respect to said body, has a higher elastic modulus than said third vibrator.