Abstract: An underwater vehicle for performing a variety of linear motions and turning motions with better stability and agility is disclosed. The underwater vehicle includes a main body, a front-drive mechanism, a rear-drive mechanism, and a steering assembly. The main body has a front end and a rear end, which defines a longitudinal axis extending from the front end to the rear end of the main body. The front-drive mechanism is connected to the main body to provide a forward propelling force in a direction parallel to the longitudinal axis. The steering assembly is fixed to the rear end and coupled to the rear-drive mechanism. The steering assembly is configured to rotate the rear-drive mechanism with respect to the longitudinal axis by a body angle for providing a lateral force on the main body.

Abstract: The present invention provides a hetero-stiffness robotic device with a central body portion having a head end and a tail end. A rigid rotatable head propeller extends from the head end while a flexible rotatable tail propeller extends from the tail end. A head motor positioned in the central body portion rotates the rigid rotatable head propeller and a tail motor positioned in the central body portion rotates the flexible rotatable tail propeller. A controller independently controls a rotational speed of the head motor and the tail motor. The head and tail propellers may have helical shapes. The hetero-stiffness propulsion gives the robotic device a high level of environmental adaptivity over a wide range of viscosities. The device demonstrates advantages in linearity, straightness, bi-directional locomotion ability, and efficiency, which provides a critical competence for moving in low Reynolds number environments.

Abstract: An underwater vehicle for performing a variety of linear motions and turning motions with better stability and agility is disclosed. The underwater vehicle includes a main body, a front-drive mechanism, a rear-drive mechanism, and a steering assembly. The main body has a front end and a rear end, which defines a longitudinal axis extending from the front end to the rear end of the main body. The front-drive mechanism is connected to the main body to provide a forward propelling force in a direction parallel to the longitudinal axis. The steering assembly is fixed to the rear end and coupled to the rear-drive mechanism. The steering assembly is configured to rotate the rear-drive mechanism with respect to the longitudinal axis by a body angle for providing a lateral force on the main body.

Abstract: The present invention provides a hetero-stiffness robotic device with a central body portion having a head end and a tail end. A rigid rotatable head propeller extends from the head end while a flexible rotatable tail propeller extends from the tail end. A head motor positioned in the central body portion rotates the rigid rotatable head propeller and a tail motor positioned in the central body portion rotates the flexible rotatable tail propeller. A controller independently controls a rotational speed of the head motor and the tail motor. The head and tail propellers may have helical shapes. The hetero-stiffness propulsion gives the robotic device a high level of environmental adaptivity over a wide range of viscosities. The device demonstrates advantages in linearity, straightness, bi-directional locomotion ability, and efficiency, which provides a critical competence for moving in low Reynolds number environments.