Search results

For precisely presenting the swimming behavior of fish robots underwater and the practical implementation purpose, this paper aims to investigate a well-formulated fish robot model which integrates the nonlinear rigid body dynamics, kinematics and models of actuators.

This fish robot model is mainly built up by three basic parts: a balance mechanism, a four-links vibrator and a caudal fin. In the fish robot’s head, there is a balance mechanism used to control the rotations in pitch and roll directions of the fish robot by moving two movable masses. The four-links vibrator with three active joints actuated by DC motors is designed to vibrate the fish’s body. In the end of the fish robot body, a caudal fin which connects with the passive joint is developed to generate hydrodynamic thrust forces to propel the fish robot.

From the real stability tests and control verification, it is obvious that this proposed model can precisely present the swimming behavior of fish robots and possesses the potential to develop a fish-like robotic prototype.

A well-formulated model with dynamics of actuators is integrated for presenting the swimming behavior of carangiform locomotion type fish robots in this investigation. From the simulation results and the practical test of a real fish robot, the feasibility of this proposed model for building up real fish robots can be proven, and this proposed model is accurate enough to effectively present the swimming behavior of fish robots.

The purpose of this paper is to acquaint a wide audience of readers with some of the unique remote sensing and navigation capabilities of animals.

Biomimetic comparison of remote sensors evolved by animals and sensors designed by man. The study and comparison includes thermal infrared sensors used by snakes, echolocation used by bats and dolphins, and navigation methods used by birds. Countermeasures used by prey to avoid capture are also considered.

Some animals have remote sensing and navigation capabilities that are considerably more efficient than those provided by the human body or designed by man.

Sensor designers may be encouraged to use the biometic approach in the design of new sensors.

The paper provides a better understanding of animal behaviour, especially their unique abilities to remotely sense, echolocate and navigate with high accuracy over considerable distances.

The paper presents a comparison of remote sensors used by animals with those developed by humans. Remote sensor designers can learn to improve their sensor designs by studying animal sensors within a biomimetic framework.

The paper aims to develop a cownose ray-inspired robotic fish which can be propelled by oscillating and chordwise twisting pectoral fins.

The bionic pectoral fin which can simultaneously realize the combination of oscillating motion and chordwise twisting motion is designed based on analyzing the movement of cownose ray’s pectoral fins. The structural design and control system construction of the robotic fish are presented. Finally, a series of swimming experiments are carried out to verify the effectiveness of the design for the bionic pectoral fin.

The experimental results show that the deformation of the bionic pectoral fin can be well close to that of the cownose ray’s. The bionic pectoral fin can produce effective angle of attack, and the thrust generated can propel robotic fish effectively. Furthermore, the tests of swimming performance in the water tank show that the robotic fish can achieve a maximum forward speed of 0.43 m/s (0.94 times of body length per second) and an excellent turning maneuverability with a small radius.

The oscillating and pitching motion can be obtained simultaneously by the active control of chordwise twisting motion of the bionic pectoral fin, which can better imitate the movement of cownose ray’s pectoral fin. The designed bionic pectoral fin can provide an experimental platform for further study of the effect of the spanwise and chordwise flexibility on propulsion performance.

This paper aims to carry out the research on the influence of ground effect on the performance of robotic fish propelled by oscillating paired pectoral fins.

The two-dimensional ground effect model of the oscillating pectoral fin without considering flexible deformation is established by introducing a two-dimensional fluid ground effect model. The parameters of the influence of ground effect on the oscillating pectoral fin are analyzed. Finally, the ground effect test platform is built, and a series of hydrodynamic experiments are carried out to study the influence of ground effect on the propulsion performance of the robotic fish propelled by oscillating paired pectoral fins under different motion parameters.

The thickness of the trailing edge and effective clearance are two important parameters that can change the influence of ground effect on the rigid pectoral fin. The experimental results are consistent with that obtained through theoretical analysis within a certain extent, which indicates that the developed two-dimensional ground effect model in this paper can be used to analyze the influence of ground effect on the propulsion performance of the oscillating pectoral fin. The experiment results show that the average thrust increases with the decreasing distance between the robot fish and the bottom. Meanwhile, with the increase of oscillation frequency and amplitude, the average thrust increases gradually.

The developed two-dimensional ground effect model provides the theoretical basis for the further research on the influence of ground effect on the propulsion performance of the oscillating pectoral fin. It can also be used in the design of the bionic pectoral fins.

Practically all salmon fillets produced in Norway are trimmed clean of unwanted fat, bone remnants and other defects according to customer requirements. In today’s modern salmon-processing plants, the trimming operation is performed by a combination of automated trimming machines and manual post-trimming. Manual post-trimming is necessary due to the inability of current trimming machines to obtain satisfactory trimming. The purpose of this paper is to describe the work done so far toward a robotic post-trimming of salmon fillets.

A prototype concept system was developed to explore the possibility of robotic post-trimming. The concept is based on 3D machine vision, a high-speed robot manipulator and a flexible light-weight cutting knife.

The developed prototype demonstrated the feasibility of detecting a pre-defined object to be trimmed in 3D, and performing the specified trimming cut along a 3D cutting trajectory.

The developed prototype system was built and integrated – focusing so far only on a single trimming operation: the tail cut.

The originality in the paper is the description of a prototype integrated system, focused on robotic post-trimming of salmon fillets. The value is in providing a starting point for further development toward a complete robotic post-trimming of salmon fillets.

This paper aims to provide a review of the role of robots for monitoring the environment.

Following a short introduction, this paper discusses developments in aquatic, terrestrial and airborne robots for monitoring the environment. Brief conclusions are drawn.

This shows that robots are being developed for all manner of environmental monitoring applications. Aquatic devices are attracting the greatest attention but both terrestrial and airborne robots have the potential to play an important, future role. In many instances, their deployment reflects the difficulties in or impossibility of using manual monitoring methods. A longer‐term vision of large numbers of robots conducting environmental monitoring on a routine basis is unlikely to be realised unless lower cost solutions can be developed.

Environmental monitoring robots have been under development since the 1990s and this paper provides a review of recent activities.

The paper aims to present a dynamic model of flexible oscillating pectoral fin for further study on its propulsion mechanism.

The chordwise and spanwise motions of cow-nosed ray’s pectoral fin are first analyzed based on the mechanism of active/passive flexible deformation. The kinematic model of oscillating pectoral fin is established by introducing the flexible deformation. Then, the dynamic model of the oscillating pectoral fin is developed based on the quasi-steady blade element theory. A series of hydrodynamic experiments on the oscillating pectoral fin are carried out to investigate the influences of motion parameters on the propulsion performance of the oscillating pectoral fin.

The experimental results are consistent with that obtained through analytical calculation within a certain range, which indicates that the developed dynamic model in this paper is applicable to describe the dynamic characteristics of the oscillating pectoral fin approximately. The experimental results show that the average thrust of an oscillating pectoral fin increases with the increasing oscillating amplitude and frequency. However, the relationship between the average thrust and the oscillating frequency is nonlinear. Moreover, the experimental results show that there is an optimal phase difference at which the oscillating pectoral fin achieves the maximum average thrust.

The developed dynamic model provides the theoretical basis for further research on propulsion mechanism of oscillating pectoral fins. It can also be used in the design of the bionic pectoral fins.

This paper aims to develop a robofish with oscillating pectoral fins, and control it to mimic the bionic prototype by central pattern generators (CPGs).

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.

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.

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 look at the background of the robotic ideas company, Oxford Intelligent Machines, generally known as OxIM and at some of their current products such as a rehabilitation work cell for disabled people, a toolchanger and Robofish, for robotic handling in fish processing.

This paper aims to provide an insight into robot developments that use bioinspired design concepts.

Following a short introduction to biomimetics, this paper first provides examples of bioinspired terrestrial, aerial and underwater robot navigation techniques. It then discusses bioinspired locomotion and considers a selection of robotic products and developments inspired by snakes, bats, diving birds, fish and dragonflies. Finally, brief concluding comments are drawn.

The application of design concepts that mimic the capabilities and processes found in living creatures can impart robots with unique abilities. Bioinspired techniques used by insects and other organisms, notably optic flow and sunlight polarisation sensing, allow robots to navigate without the need for methods such as simultaneous localisation and mapping, GPS or inertial measurement units. Bioinspired locomotion techniques have yielded robots capable of operating in water, air and on land and in some cases, making the transition between different media.

This shows how bioinspired design concepts can impart robots with innovative and enhanced navigation and locomotion capabilities.