Biomimetic Underwater Robot Research Articles

Prototype Design of a Kind of Biomimetic Cuttlefish Underwater Robot Actuated by SMA Wires

Cuttlefish can swim with great maneuverability by undulating their fins and can swim with high speed by jetting.To mimic the muscle structure of the cuttlefish,a kind of flexible fin unit which can bend to both sides and a kind of biomimetic mantle which can flexibly contract and expand,are developed with the structure that SMA(shape memory alloy) wires are embedded into the flexible silicone rubber.Then a kind of biomimetic undulating fin and a kind of biomimetic jet propeller based on the former design are developed to mimic the swimming mechanism of cuttlefish.And the thrust performance of both of the propellers is tested.At last,a prototype of biomimetic cuttlefish robot is developed and the swimming experiments are carried out.

2A2-M07 圧電繊維複合材料を用いた生物模倣型ソフト水中ロボットの研究開発 : 中空構造のマス型水中ロボットの試作(水中ロボット・メカトロニクス)

2A2-M07 圧電繊維複合材料を用いた生物模倣型ソフト水中ロボットの研究開発 : 中空構造のマス型水中ロボットの試作(水中ロボット・メカトロニクス)

IR 센서 및 Compass 센서를 이용한 생체 모방형 수중 로봇의 장애물 인식 및 회피

In this paper, the IR and compass sensors for the underwater system were used. The walls of the water tank have been recognized and avoided treating the walls as obstacles by the bio-mimetic underwater robot. This paper is consists of two parts: 1.The hardware part for the IR and compass sensors and 2.The software part for obstacle avoidance algorithm while the bio-mimetic robot is swimming with the obstacle recognition. Firstly, the hardware part controls through the RS-485 communications between a microcontroller and the bio-mimetic underwater robot. The software part is simulated for obstacle recognition and collision avoidance based upon the data from IR and compass sensors. Actually, the bio-mimetic underwater robot recognizes where is the obstacle as well as where is the bio-mimetic robot itself while it is moving in the water. While the underwater robot is moving at a constant speed recognizing the wall of water tank as an obstacle, an obstacle avoidance algorithm is applied for the wall following swimming based upon the IR and compass sensor data. As the results of this research, it is concluded that the bio-mimetic underwater robot can follow the wall of the water tank efficiently, while it is avoiding collision to the wall.

Review of biomimetic underwater robots using smart actuators

In this paper, biomimetic underwater robots built using smart actuators, e.g., a shape memory alloy (SMA), an ionic polymer metal composite (IPMC), lead zirconate titanate (PZT), or a hybrid SMA and IPMC actuator, are reviewed. The effects of underwater environment were also considered because smart actuators are often affected by their external environment. The characteristics of smart actuators are described based on their actuating conditions and motion types. Underwater robots are classified based on different swimming modes. We expanded our classification to non-fish creatures based on their swimming modes. The five swimming modes are body/caudal actuation oscillatory (BCA-O), body/caudal actuation undulatory (BCA-U), median/paired actuation oscillatory (MPA-O), median/paired actuation undulatory (MPA-U), and jet propulsion (JET). The trends of biomimetic underwater robots were analyzed based on robot speed (body length per second, BL/s). For speed per body length, robots using an SMA as an actuator are faster than robots using an IPMC when considering a similar length or weight. Robots using a DC motor are longer while their speeds per body length are similar, which means that robots using smart actuators have an advantage of compactness. Finally, robots (using smart actuators or a motor) were compared with underwater animals according to their speed and different swimming modes. This review will help in setting guidelines for the development of future biomimetic underwater robots, especially those that use smart actuators.

Swimming Mechanism of Squid/Cuttlefish and Its Application to Biomimetic Underwater Robots

According to the shortcomings of most robot fish,such as not incorporating elastic mechanism to improve energy efficiency and poor pressure resistance capability,squid/cuttlefish,which have excellent swimming capability and pressure-resistant structure,are studied.Swimming mechanism of squid/cuttlefish jetting and fin undulating propulsion is analyzed,and the equations of jet thrust,propulsive efficiency of jetting period and whole hydrodynamic propulsion cycle are given.The advantages of squid/cuttlefish compound swimming are good performance at both high and low speeds,being capable of changing swimming direction immediately,low noise,and that thrust can be generated even if jet velocity is slower than that of the surrounding fluid.In order to explain swimming mechanism in depth,the muscle arrangements and functions of mantle and fin muscular hydrostats,the two locomotory systems,are studied.The muscular hydrostats not only serve to the skeleton support of body,to carry out movement and to generate force,but also have considerable pressure-resistant capability.The hydrostatic pressure in and out of the mantle of most squid/cuttlefish is equal due to no gas filled tissue in their body,which improves their pressure-resistant capability further. During the movement,energetic efficiency is improved because energy is saved by the elastic spring mechanism.If the characteristics of swimming mechanism,muscular and elastic mechanism could be applied to biomimetic underwater robot,the robot would be more efficient,flexible and pressure-resistant.

Modeling and simulation of an artificial muscle and its application to biomimetic robot posture control

The shape memory effect exhibited by Nitinol wire can be utilized to construct an artificial muscle. The muscle is activated by an electric current, which produces heat and initiates a phase transformation. The Nitinol artificial muscle stress–strain–power relationship was determined by experiments, and a mathematical model was developed. The artificial muscle model was utilized for the posture control of a biomimetic underwater robot. The optimal activation patterns for height, pitch, and roll postures were determined. Simulation results for the height postures are in agreement with the experiments. The separation between the center of gravity and the centroid of the robot has a stabilizing effect on pitch and roll postures.

Dynamic Modeling and Hydrodynamic Performance of Biomimetic Underwater Robot Locomotion

We developed a dynamic model of a Nitinol artificial muscle activated biomimetic robot. The robot was reverse engineered from the American lobster and built in the Biomimetic Underwater Robot Program at Northeastern University. It is intended for autonomous remote-sensing operations in shallow waters. An experimentally based Nitinol artificial muscle model was integrated into the robot dynamic model. The hydrodynamic characteristics of the robot were determined experimentally. The muscle control signals were generated by utilizing a readily available biomimetic control architecture. The effects of the timing parameters were investigated. Simulations indicate that the developed robot is able to locomote with high stability. It can walk against constant currents and surge.