Design and control of a soft biomimetic batoid robot

[摘要] This thesis presents the work accomplished in the design, experimental characterization and control of a soft batoid robot. The shape of the robot is based on the body of the common stingray, Dasyatidae, and is made of soft silicone polymers. Although soft batoid robots have been previously studied, the novelty brought by the present work centers around autonomy and scale, making it suitable for field operations. The design of the robot relies on the organismic consideration that the stingray body is rigid at its center and flexible towards its fins. Indeed, all mechanical and electrical parts are inside a rigid shell embedded at the center of the robot;;s flexible body. The silicone forms a continuum which encases the shell and constitutes the two pectoral fins of the robot. The core idea of this design is to make use of the natural modes of vibration of the soft silicone to recreate the fin kinematics of an actual stingray. By only actuating periodically the front of the fins, a wave propagating downstream the soft fins is created, producing a net forward thrust. Experiments are conducted to quantify the robot;;s swimming capabilities at different regimes of actuation. The forward velocity, the stall forces produced by the robot when it is flapping its fins while being clamped, and the power consumption of the actuation are all measured. The peak velocity of the robot is 0.35 body-length per second and is obtained for a flapping frequency of 1.4 Hz and a flapping amplitude of 30°. At a flapping frequency of 2 Hz, and an amplitude of 30°, the maximum stall forward force of the robot averages at 45 Newtons and peaks at 150 Newtons. Other data collected is used to better understand the hydrodynamics of the robot.

[发布机构] Massachusetts Institute of Technology