Design of a Novel Robotic Fish Structure Utilizing PVC Gel Actuators

In this research work, it has been designed a bionic robot fish structure, can swim underwater. The active compact body is powered by eight sets of symmetric PVC gel actuators with a caudal fin. The robot’s 200 mm-long, fish structure design incorporates a 55.52 angle to optimize the fish dynamics movement. It’s a fast and smooth operation and can swim. The robot can swim fast and quietly by using the right positions and the appropriate actuators on PVC gel actuators. This design entails a unique architecture that enables the robot to move safely and unobtrusively at the same time, which makes it suitable equipment for different exploration and surveillance missions in the water with speed and silent operation as the foremost concern.

Effect of an Artificial Caudal Fin on the Performance of a Biomimetic Fish Robot Propelled by Piezoelectric Actuators

This paper addresses the design of a biomimetic fish robot actuated by piezoeeramic actuators and the effect of artificial caudal fins on the fish robot＇s performance. The limited bending displacement produced by a lightweight piezocomposite actuator was amplified and transformed into a large tail beat motion by means of a linkage system. Caudal fins that mimic the shape of a mackerel fin were fabricated for the purpose of examining the effect of caudal fm characteristics on thrust production at an operating frequency range. The thickness distribution of a real mackerel＇s fin was measured and used to design artificial caudal fins. The thrust performance of the biomimetic fish robot propelled by fins of various thicknesses was examined in terms of the Strouhal number, the Froude number, the Reynolds number, and the power consumption. For the same fm area and aspect ratio, an artificial caudal fin with a distributed thickness shows the best forward speed and the least power consumption.

3-D Locomotion control for a biomimetic robot fish

This paper concerns with 3-D locomotion control methods for a biomimetic robot fish. The system architecture of the fish is firstly presented based on a physical model of carangiform fish. The robot fish has a flexible body, a rigid caudal fin and a pair of pectoral fins, driven by several servomotors. The motion control of the robot fish are then divided into speed control, orientation control, submerge control and transient motion control, corresponding algorithms are detailed respectively. Finally, experiments and analyses on a 4-link, radio-controlled robot fish prototype with 3-D locomotion show its good performance.

Mechanics Unloading Analysis and Experimentation of a New Type of Parallel Biomimetic Shoulder Complex

The structure design for high ratio of carrying capacity to deadweight is one of the challenges for the bionic mechanism,while the problem concerning high carrying capacity has not yet be solved for the existing shoulder complex.A new type biomimetic shoulder complex,which adopts 3-PSS/S（P for prismatic pair,S for spherical pair） spherical parallel mechanism（SPM）,is proposed.The static equilibrium equations of each component are established by using the vector method and the equations for constrain forces with certain load are solved.Then the constrain force on the middle limb and that on the side limbs are compared in order to verify the unloading performance of the mechanism.In addition,the prototype mechanism of the shoulder complex is developed,and the force feedback experiment is conducted to verify the static analysis,which indicates that the middle limb suffers most of the external force and the effect of mechanics unloading is achieved.The 3-PSS/S spherical parallel mechanism is presented for the shoulder complex,and the realization of mechanics unloading is benefit for the improvement of the carrying capacity of the shoulder complex.

Robot Pheromone Communication Using Vortex Ring Transmission

Unpredictable air movements have proved to be a problem in previous studies investigating robot communication by means of airborne pheromone chemicals. The project described in this paper investigates the use of air vortex rings as a means of carrying pheromone chemicals between transmitting and receiving robots. Sensitivity to chemicals including pheromones released by conspecifics is essential for many aspects of an insect's life. They assist in finding food, locating a mate, avoiding danger and help coordinate the activities of social insects. In the future, autonomous robots will be challenged by many situations similar to those that face insects and other simple creatures. Chemical communication may prove useful for these robots as well. This paper describes the equipment developed for generating and detecting vortex rings. Results of experiments involving location and tracking of a sequence of pheromone vortex rings are also presented.

A Bionic Starfish Adsorption Crawling Soft Robot

A variety of soft wall-climbing robots have been developed that can move in certain patterns.Most of these soft robots can only move on conventional surfaces and lack adaptability to complex surfaces.Improving the adaptability of soft robots on complex surfaces is still a challenging problem.To this end,we study the layered structure of the starfish tube foot and the valve flap structure in the water vascular system,and use an ultrasonic stress detector to study the stiffness distribution of the arm structure.Inspired by the motion of the starfish,we present a bionic soft wall-climbing robot,which is driven by two groups of pneumatic feet and achieves body bending through active adaptation layers.We design the structure of the foot to flex to provide driving force,and there are suction cups at the end of the foot to provide suction.The soft foot has a simple structure design,adapts to a variety of surfaces,and does not damage the surface of the substrate.Variable stiffness layers achieve stiffness changes by the principle of line blocking.The Central Pattern Generator theory is introduced to coordinately control the multiple feet of the robot.After experiments,we verify the adaptability of the soft robot to curved surfaces.The research may provide a reference for the design and development of crawling soft robots on complex surfaces.

Bioinspired Closed-loop CPG-based Control of a Robotic Manta for Autonomous Swimming

Fish in nature exhibit a variety of swimming modes such as forward swimming,backward swimming,turning,pitching,etc.,enabling them to swim in complex scenes such as coral reefs.It is still difficult for a robotic fish to swim autonomously in a confined area as a real fish.Here,we develop an untethered robotic manta as an experimental platform,which consists of two flexible pectoral fins and a tail fin,with three infrared sensors installed on the front,left,and right sides of the head to sense the surrounding obstacles.To generate multiple swimming modes of the robotic manta and online switching of different modes,we design a closed-loop Central Pattern Generator(CPG)controller based on distance information and use a combination of phase difference and amplitude of the CPG model to achieve stable and rapid adjustment of yaw angle.To verify the autonomous swimming ability of the robotic manta in complex scenes,we design an experimental scenario with a concave obstacle.The experimental results show that the robotic manta can achieve forward swimming,backward swimming,in situ turning within the concave obstacle,and finally exit from the area safely while relying on the perception of external obstacles,which can provide insight into the autonomous exploration of complex scenes by the biomimetic robotic fish.Finally,the swimming ability of the robotic manta is verified by field tests.

A survey of the development of biomimetic intelligence and robotics

Biomimetics is the development of novel theories and technologies by emulating the models and systems of nature.The transfer of function from biological science into engineering promotes emerging research areas across many disparate disciplines.Recently,advances in biomimetic intelligence and robotics have gained great popularity.Biomimetic robotics are designed with biological characteristics and functions to be applied in different scenarios,such as humanoid robot in the home environment,quadruped robot in the field,and bird-like flying robot in the sky.Biomimetic intelligence aims to solve many complex problems by studying the principles of biological systems,resulting in a series of efficient algorithms,such as the genetic algorithm and neural network.Biomimetic intelligence further facilitates the performance of biomimetic robotics,making it possible to be deployed in more and more practical applications.This survey introduces the development of biomimetic intelligence and biomimetic robotics.We survey different biomimetic robots,biomimetic sensors and sensing technologies,and popular biomimetic intelligence algorithms.The conclusion is drawn by discussing current challenges and future research directions.

Design,Mobility Analysis and Gait Planning of a Leech-like Soft Crawling Robot with Stretching and Bending Deformation

Soft climbing/crawling robots have been attracting increasing attention in the soft robotics community,and many prototypes with basic locomotion have been implemented.Most existing soft robots achieve locomotion by planar bending deformation and lack sufficient mobility.Enhancing the mobility of soft climbing/crawling robots is still an open and challenging issue.To this end,we present a novel pneumatic leech-like soft robot,Leechbot,with both bending and stretching deformation for locomotion.With a morphological structure,the robot consists of a three-chambered actuator in the middle for the main motion,two chamber-net actuators that act as ankles,and two suckers at the ends for anchoring on surfaces.The peristaltic motion for locomotion is implemented by body stretching,and direction changing is achieved by body bending.Due to the novel design and two deformation modes,the robot can make turns and transit between different surfaces;the robot,hence,has excellent mobility.The development of the robot prototype is presented in detail in this paper.To control its motion,tests were carried out to determine the relationship between step length and air pressure as well as the relationship between motion speed and periodic delay time.A kinematic model was established,and the kinematic mobility and surface transitionability were analyzed.Gait planning based on the inflating sequence of the actuating chambers is presented for straight crawling,turn making,and transiting between surfaces and was verified by a series of experiments with the prototype.The results show that a high mobility in soft climbing/crawling robots can be achieved by a novel design and by proper gait planning.

Design and Realization of a Novel Hybrid-Drive Robotic Fish for Aquaculture Water Quality Monitoring

Thunniform swimmers(tuna)have a swinging narrow sequence stalk and a moon-shaped tail fin,which performs poorly at slow speed,higher acceleration and turning maneuverability.In most cases,faster speed and higher maneuverability are mutually rejection for most marine creatures and their robotic opponents.This paper presents a novel hybrid tuna-like swimming robot for aquaculture water quality monitoring,which interleaves faster speed and higher maneuverability.The robotic prototype emphasizes on streamlining and enhanced maneuverability mechanism designs in conjunction with a narrow caudal propeller to the tail.The innovative design endows the robot to easily execute the multi-mode swimming gait,including forward swimming,turning,diving/surfacing.The capabilities of our robot are validated through a series of indoor swimming pool and field breeding ponds.The robotic fish can achieve a maximum speed up to about 1.16 m/s and a minimum turning radius less than 0.46 Body Lengths(BL)and its maximum turning speed can reach 78.6∘/s.Due to its high speed,maneuverability and relatively small size,the robotic fish shed light on intelligent monitoring in complex aquatic environments.

Design,Modeling,and Control of Biomimetic Fish Robot:A Review

A comprehensive review on bio-inspired fish robots has been done in this article with an enhanced focus on swimming styles,actuators,hydrodynamics,kinematic-dynamic modeling,and controllers.Swimming styles such as body and/or caudal fin and median and/or paired fin and their variants are discussed in detail.Literature shows that most fish robots adapt carangiform in body and/or caudal fin type swimming as it gives significant thrust with a maximum speed of 3.7 ms 1 in iSplash-II.Applications of smart or soft actuators to enhance real-time dynamics was studied from literature,and it was found that the robot built with polymer fiber composite material could reach a speed of 0.6 m s However,dynamic modeling is relatively complex,and material selection needs to be explored.The numerical and analytical methods in dynamic modeling have been investigated highlighting merits and demerits.Hydrodynamic parameter estimation through the data-driven model is widely used in offline,however online estimation of the same need to be explored.Classical controllers are frequently used tor navigation and stabilization,which often encounters the linearization problem and hence,can be replaced with the state-of-the-art adaptive and intelligent controller.This article also summarizes the potential research gaps and future scopes.

Development of an Amphibious Turtle-Inspired Spherical Mother Robot

Robots play an important role in underwater monitoring and recovery operations, such as pollution detection, submarine sampling and data collection, video mapping, and object recovery in dangerous places. However, regular-sized robots may not be suitable for applications in some restricted underwater environments. Accordingly, in previous research we designed several novel types of bio-inspired microrobots using Ionic Polymer Metal Composite （IPMC） and Shape Memory Alloy （SMA） ac- tuators. These microrobots possess some attributes of compact structure, multi-functionality, flexibility, and precise positioning. However, they lack the attributes of long endurance, stable high speed, and large load capacity necessary for real-world appli- cations. To overcome these disadvantages, we proposed a mother-son robot system, composed of several microrobots as sons and a newly designed amphibious spherical robot as the mother. Inspired by amphibious turtles, the mother robot was designed with a spherical body and four legs with two Degrees of Freedom （DOF）. It is actuated by four vectored water-jet propellers and ten servomotors, and it is capable of walking on land and cruising underwater. We analysed the mother robot＇s walking and underwater cruising mechanisms, constructed a prototype, and carried out a series of experiments to evaluate its amphibious motions. Good motion performance was observed in the experiments.

Bioinspired Closed-loop CPG-based Control of a Robot Fish for Obstacle Avoidance and Direction Tracking

This paper presents a study on bioinspired closed-loop Central Pattern Generator(CPG)based control of a robot fish for obstacle avoidance and direction tracking.The biomimetic robot fish is made of a rigid head with a pair of pectoral fins,a wire-driven active body covered with soft skin,and a compliant tail.The CPG model consists of four input parameters:the flapping amplitude,the flapping angular velocity,the flapping offset,and the time ratio between the beat phase and the restore phase in flapping.The robot fish is equipped with three infrared sensors mounted on the left,front and right of the robot fish,as well as an inertial measurement unit,from which the surrounding obstacles and moving direction can be sensed.Based on these sensor signals,the closed-loop CPG-based control can drive the robot fish to avoid obstacles and to track designated directions.Four sets of experiments are presented,including avoiding a static obstacle,avoiding a moving obstacle,tracking a designated direction and tracking a designated direction with an obstacle in the path.The experiment results indicated that the presented control strategy worked well and the robot fish can accomplish the obstacle avoidance and direction tracking effectively.

Development of amphibious biomimetic robots

Amphibious robots are becoming increasingly important for civilian,scientific,and environmental missions.They are widely used in disaster rescue,ecosystem monitoring,and entertainment.However,some have two different locomotion systems that need to be changed manually to fulfill both swimming in the water and moving on land,which may reduce their efficiency and reliability.Applying bioinspiration and biomimetics,many recently developed amphibious robots can undertake various tasks in complex amphibious environments with high mobility,flexibility,and energy efficiency.This review overviews the latest developments in amphibious robots,emphasizing biomimetic design concepts,backbone driving mechanisms,and typical applications.The performance indices of amphibious robots mimicking 13 different natural sources are compared,based on 10 different propulsion principles/modes,travel speed,working efficiency,maneuverability,and stability.Finally,the current challenges and perspectives of amphibious bio-inspired robots are discussed.This article summarizes the current types of amphibious robots and their movement and behavior solutions.The design concepts and operating mechanisms of amphibious robots reviewed here can be readily applied to other robotic studies.

On the thrust performance of an ionic polymer-metal composite actuated robotic fish: Modeling and experimental investigation

In this paper, we theoretically predict and experimentally measure the thrust efficiency of a biomimetic robotic fish, which is propelled by an ionic polymer-metal composite （IPMC） actuator. A physics-based model that consists of IPMC dynamics and hydrodynamics was proposed, and simulation was conducted. In order to test the thrust performance of the robotic fish, a novel experimental apparatus was developed for hydrodynamic experiments. Under a servo towing system, the IPMC fish swam at a self-propelled speed where external force is averagely zero. Experimental results demonstrated that the theoretical model can well predict the thrust efficiency of the robotic fish. A maximum thrust efficiency of 2.3x10-3 at 1 Hz was recorded experi- mentally, the maximum thrust force was 0.0253 N, recorded at 1.2 Hz, while the maximum speed was 0.021 m/s, recorded at 1.5 Hz, and a peak power of 0.36 W was recorded at 2.6 Hz. Additionally, the optimal actuation frequency for the thrust efficiency was also recorded at the maximum self-propelled speed. The present method of examining the thrust efficiency may also be applied to the studies of other types of smart material actuated underwater robots.

Experimental Study on the Improvement of Yaw Stability by Coordination Control between the Caudal Fin and Anal Fin

Due to the unique locomotion,the head-shaking problem of biomimetic robotic fish inevitably occurs during rectilinear locomotion,which strongly hinders its practical applications.In this paper,we experimentally study this problem by proposing the method of coordination control between the caudal fin and anal fin.First,an untethered biomimetic robotic fish,equipped with an anal fin,a caudal fin and two pectoral fins,is developed as the experimental platform.Second,a Central Pattern Generator(CPG)-based controller is used to coordinate the motions of the anal fin and caudal fin.Third,extensive experiments are conducted to explore different combinations of the flapping frequencies,the flapping amplitudes,and the phase differences between the anal fin and caudal fin.Notably,through proper control of the anal fin,the amplitude of the yaw motion can be as small as 4.32°,which sees a 65%improvement compared to the scenario without anal fin,and a 57%improvement compared to that with a stationary anal fin.This paper provides a novel way to alleviate the head-shaking problem for biomimetic robotic fish,and first test this method on an untethered,freely swimming robotic platform,which can shed light on the development of underwater robotics.

Optimal design and motion control of biomimetic robotic fish

This paper is concerned with the design, optimization, and motion control of a radiocontrolled, multi-link, free-swimming biomimetic robotic fish based on an optimized kinematic and dynamic model of fish swimming. The performance of the robotic fish is determined by both the fish＇s morphological characteristics and kinematic parameters. By applying ichthyologic theories of propulsion, a design framework that takes into consideration both mechatronic constraints in physical realization and feasibility of control methods is presented, under which a multiple linked robotic fish that integrates both the carangiform and anguilliform swimming modes can be easily developed. Taking account of both theoretic hydrodynamic issues and practical problems in engineering realization, the optimal link-lengthratios are numerically calculated by an improved constrained cyclic variable method, which are successfully applied to a series of real robotic fishes. The rhythmic movements of swimming are driven by a central pattern generator （CPG） based on nonlinear oscillations, and up-and-down motion by regulating the rotating angle of pectoral fins. The experimental results verify that the presented scheme and method are effective in design and implementation.

Distance-directed Target Searching for a Deep Visual Servo SMA Driven Soft Robot Using Reinforcement Learning

Performing complex tasks by soft robots in constrained environment remains an enormous challenge owing to the limitations of flexible mechanisms and control methods.In this paper,a novel biomimetic soft robot driven by Shape Memory Alloy(SMA)with light weight and multi-motion abilities is introduced.We adapt deep learning to perceive irregular targets in an unstructured environment.Aiming at the target searching task,an intelligent visual servo control algorithm based on Q-leaming is proposed to generate distance-directed end effector locomotion.In particular,a threshold reward system for the target searching task is proposed to enable a certain degree of tolerance for pointing errors.In addition,the angular velocity and working space of the end effector with load and without load based on the established coupling kinematic model are presented.Our framework enables the trained soft robot to take actions and perform target searching.Realistic experiments under different conditions demonstrate the convergence of the learning process and effectiveness of the proposed algorithm.

Auto-generating of 2D tessellated crease patterns of 3D biomimetic spring origami structure

Computational simulations can accelerate the design and modelling of origami robots and mechanisms.This paper presents a computational method using algorithms developed in Python to generate different tessellated origami crease patterns simultaneously.This paper aims to automate this process by introducing a system that automatically generates origami crease patterns in Scalable Vector Graphics format.By introducing different parameters,variations of the same underlying tessellated crease pattern can be obtained.The user interface consists of an input file where the user can input the desired parameters,which are then processed by an algorithm written in Python to generate the respective origami 2D crease patterns.These origami crease patterns can serve as inputs to current origami design software and algorithms to generate origami design models for faster and easier visual comparison.This paper utilizes a basic biomimetic inspiration origami pattern to demonstrate the functionality by varying underlying crease pattern parameters that give rise to symmetric and asymmetric spring origami 3D structures.Furthermore,this paper conducts a qualitative analysis of the origami design outputs of an origami simulator from the input crease patterns and the respective manual folding of the origami structure.

Human-Like Robot Sensing Mediated by Body Heat

This paper presents a novel robotic sensor system that can monitor volatile chemicals and airflow. The system is modelled on characteristics of the human body that are thought to have a significant influence on the human odour and airflow senses. In particular, the effect of buoyant airflow due to body heat acts to gather volatile chemicals over large areas of the human body and carry them to the nose. It is postulated that this effect increases the receptive area for human olfaction. In addition, the interaction between rising air heated by the body and external airflow produces a temperature distribution about head height that can be used to infer airflow direction and magnitude. A heated sensor system was constructed to investigate these effects and the resulting sensor was mounted on a mobile robot. The design of the sensor system is described. Results are presented which demonstrate its ability to measure airflow direction and detect chemical signals over a wider receptive field compared with an unheated sensor.