Motion Analysis of a Manta Robot for Underwater Exploration by Propulsive Experiments and the Design of Central Pattern Generator

2014 ◽  
Vol 8 (2) ◽  
pp. 231-237 ◽  
Author(s):  
Masaaki Ikeda ◽  
◽  
Shigeki Hikasa ◽  
Keigo Watanabe ◽  
Isaku Nagai
Keyword(s):  
Autonomous Underwater Vehicles ◽  
Central Pattern Generators ◽  
Underwater Vehicles ◽  
Loud Noise ◽  
Motion Generation ◽  
Pectoral Fins ◽  
Underwater Propulsion ◽  
Pattern Generators ◽  
Underwater Exploration ◽  
Manta Ray

Although, Autonomous Underwater Vehicles (AUVs) used for investigating underwater ecology have attracted the attention of underwater researchers, conventional AUVs moved underwater by screw propellers generate loud noise thatmay disturb the underwater environments and inhabitants to be observed. This paper discusses the development of an AUV that mimics the manta ray. Central Pattern Generators (CPGs) are also proposed to generate the motion of pectoral fins for Manta robot. The practicality of the robot is checked in underwater propulsion experiments, and the effectiveness of the proposed motion generation method is demonstrated in numerical simulations.

Thrust Production in Highly Flexible Pectoral Fins: A Computational Dissection

2011 ◽  
Vol 45 (4) ◽  
pp. 56-64 ◽  
Author(s):  
Srinivas Ramakrishnan ◽  
Meliha Bozkurttas ◽  
Rajat Mittal ◽  
George V. Lauder
Keyword(s):  
Computational Analysis ◽  
Autonomous Underwater Vehicles ◽  
Underwater Vehicles ◽  
Bluegill Sunfish ◽  
Robust Performance ◽  
Pectoral Fin ◽  
Pectoral Fins ◽  
And Performance ◽  
Thrust Production ◽  
Computational Dissection

AbstractBluegill sunfish pectoral fins represent a remarkable success in evolutionary terms as a means of propulsion in challenging environments. Attempts to mimic their design in the context of autonomous underwater vehicles have overwhelmingly relied on the analysis of steady swimming. Experimental observations of maneuvers reveal that the kinematics of fin and wake dynamics exhibit characteristics that are distinctly different from steady swimming. We present a computational analysis that compares, qualitatively and quantitatively, the wake hydrodynamics and performance of the bluegill sunfish pectoral fin for two modes of swimming: steady swimming and a yaw turn maneuver. It is in this context that we comment on the role that flexibility plays in the success of the pectoral fin as a versatile propulsor. Specifically, we assess the performance of the fin by conducting a “virtual dissection” where only a portion of fin is retained. Approximately 90% of peak thrust for steady swimming is recovered using only the dorsal half. This figure drops to 70% for the yaw turn maneuver. Our findings suggest that designs based on fin analysis that account for various locomotion modes can lead to more robust performance than those based solely on steady swimming.

Applying central pattern generators to control the robofish with oscillating pectoral fins

2015 ◽  
Vol 42 (5) ◽  
pp. 392-405 ◽  
Author(s):  
Yong Cao ◽  
Shusheng Bi ◽  
Yueri Cai ◽  
Yuliang Wang
Keyword(s):  
Design Methodology ◽  
Three Dimensional ◽  
Central Pattern Generators ◽  
Content Type ◽  
Pectoral Fins ◽  
Cownose Ray ◽  
Pattern Generators ◽  
And Control ◽  
Scientific Tool ◽  
Oscillation Characteristics

Purpose – This paper aims to develop a robofish with oscillating pectoral fins, and control it to mimic the bionic prototype by central pattern generators (CPGs). Design/methodology/approach – First, the oscillation characteristics of the cownose ray were analyzed quantitatively. Second, a robofish with multi-joint pectoral fins was developed according to the bionic morphology and kinematics. Third, the improved phase oscillator was established, which contains a spatial asymmetric coefficient and a temporal asymmetric coefficient. Moreover, the CPG network is created to mimic the cownose ray and accomplish three-dimensional (3D) motions. Finally, the experiments were done to test the authors ' works. Findings – The results demonstrate that the CPGs is effective to control the robofish to imitate the cownose ray realistically. In addition, the robofish is able to accomplish 3D motions of high maneuverability, and change among different swimming modes quickly and smoothly. Originality/value – The research provides the method to develop a robofish from both 3D morphology and kinematics. The motion analysis and CPG control make sure that the robofish has the features of high maneuverability and camouflage. It is useful for military underwater applications and underwater detections in narrow environments. Second, this work lays the foundation for the autonomous 3D control. Moreover, the robotic fish can be taken as a scientific tool for the fluid bionics research.

A Relationship Between Sweep Angle of Flapping Pectoral Fins and Thrust Generation

2018 ◽  
Vol 11 (1) ◽  
Author(s):  
Soheil Arastehfar ◽  
Chee-Meng Chew ◽  
Athena Jalalian ◽  
Gunawan Gunawan ◽  
Khoon Seng Yeo
Keyword(s):  
Reynolds Number ◽  
Autonomous Underwater Vehicles ◽  
Water Channel ◽  
Underwater Vehicles ◽  
Flapping Wings ◽  
Decision Making Process ◽  
Sweep Angle ◽  
Pectoral Fins ◽  
Thrust Generation ◽  
Geometrical Factors

Propulsive capability of manta rays' flapping pectoral fins has inspired many to incorporate these fins as propulsive mechanisms for autonomous underwater vehicles. In particular, geometrical factors such as sweep angle have been postulated as being influential to these fins' propulsive capability, specifically their thrust generation. Although effects of sweep angle on static/flapping wings of aircrafts/drones have been widely studied, little has been done for underwater conditions. Furthermore, the findings from air studies may not be relatable to the underwater studies on pectoral fins because of the different Reynolds number (compared to the flapping wings) and force generation mechanism (compared to the static wings). This paper aims to establish a relationship between the sweep angle and thrust generation. An experiment was conducted to measure the thrust generated by 40 fins in a water channel under freestream and still water conditions for chord Reynolds number between 2.2 × 104 and 8.2 × 104. The fins were of five different sweep angles (0 deg, 10 deg, 20 deg, 30 deg, and 40 deg) that were incorporated into eight base designs of different flexibility characteristics. The results showed that the sweep angle (within the range considered) may have no significant influence on these fins' thrust generation, implying no significant effects on thrust under uniform flow condition and on the maximum possible thrust under still water. Overall, it can be concluded that sweep angle may not be a determinant of thrust generation for flapping pectoral fins. This knowledge can ease the decision-making process of design of robots propeled by these fins.

CPG Control of a Tensegrity Morphing Structure for Biomimetic Applications

2008 ◽  
Vol 58 ◽  
pp. 137-142 ◽  
Author(s):  
Thomas K. Bliss ◽  
Tetsuya Iwasaki ◽  
Hilary Bart-Smith
Keyword(s):  
Natural Frequencies ◽  
Autonomous Underwater Vehicle ◽  
Central Pattern Generators ◽  
Control Input ◽  
Rhythmic Movements ◽  
Tensegrity Structure ◽  
Efficient Control ◽  
Morphing Structure ◽  
Pattern Generators ◽  
Manta Ray

Rhythmic movements associated with animal locomotion are controlled by neuronal circuits known as central pattern generators (CPG). These biological control systems appear to entrain to the natural frequencies of the mechanical systems they control, taking advantage of the resonance of the structure, resulting in efficient control. The ultimate goal is employing these controls in a biomimetic autonomous underwater vehicle so as to capture, and possibly improve upon, the performance capabilities of animals like the manta ray. To this end, this paper investigates the CPG control of a simple tensegrity structure. The dynamics of a tensegrity structure are linearized about a nominal configuration, and a synthesized CPG is used as the control input. Successful integration is shown by the CPG's ability to tune the structure's first mode.

Effect of Central Pattern Generators Depended Different Walking Strategies on Gait Ability of Patients after Stroke

2017 ◽  
Vol 27 (2) ◽  
pp. 40
Author(s):  
Hua WU ◽  
Zaihua RU ◽  
Congying XU ◽  
Xudong GU ◽  
Jianming FU
Keyword(s):  
Central Pattern Generators ◽  
Pattern Generators

Rhythmic Pattern Generation in Invertebrates

2018 ◽  
pp. 390-400
Author(s):  
Astrid A. Prinz
Keyword(s):  
Central Pattern Generators ◽  
Pattern Generation ◽  
Rhythmic Pattern ◽  
Neuronal Circuit ◽  
Neuronal Circuits ◽  
Timing Circuit ◽  
Core Components ◽  
Pattern Generators

This chapter begins by defining central pattern generators (CPGs) and proceeds to focus on one of their core components, the timing circuit. After arguing why invertebrate CPGs are particularly useful for the study of neuronal circuit operation in general, the bulk of the chapter then describes basic mechanisms of CPG operation at the cellular, synaptic, and network levels, and how different CPGs combine these mechanisms in various ways. Finally, the chapter takes a semihistorical perspective to discuss whether or not the study of invertebrate CPGs has seen its prime and what it has contributed—and may continue to offer—to a wider understanding of neuronal circuits in general.

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