The use of oscillating flexible fins in propulsion has been the subject of several studies in recent years, but attention is rarely paid to the specific role of stiffness profile in thrust production. Stiffness profile is defined as the variation in local chordwise bending stiffness (EI) of a fin, from leading to trailing edge. In this study, flexible fins with a standard NACA0012 shape were tested alongside fins with a stiffness profile mimicking that of a Pumpkinseed Sunfish (Lepomis gibbosus). The fins were oscillated with a pitching sinusoidal motion over a range of frequencies and amplitudes, while torque, lateral force and static thrust were measured.
Over the range of oscillation parameters tested, it was shown that the fin with a biomimetic stiffness profile offered a sig-nificant improvement in static thrust, compared to a fin of similar dimensions with a standard NACA0012 aerofoil profile. The biomimetic fin also produced thrust more consistently over each oscillation cycle.
A comparison of fin materials of different stiffness showed that the improvement was due to the stiffness profile itself, and was not simply an effect of altering the overall stiffness of the fin. Fins of the same stiffness profile were observed to follow the same thrust-power curve, independent of the stiffness of the moulding material. Biomimetic fins were shown to produce up to 26% greater thrust per watt of input power, within the experimental range.

The cow-nosed ray is studied as natural sample of a flapping-foil robotic fish. Body structure, motion discipline, and dy-namic foil deformation of cow-nosed ray are analyzed. Based on the analysis results, a robotic fish imitating cow-nosed ray, named Robo-ray II, mainly composed of soft body, flexible ribs and pneumatic artificial muscles, is developed. Structure and swimming morphology of the robotic prototype are as that of a normal cow-nosed ray in nature. Key propulsion parameters of Robo-ray II at normal conditions, including the St Number at linear swimming, thrust coefficient at towing are studied through experiments. The suitable driving parameters are confirmed considering the efficiency and swimming velocity. Swimming velocity of 0.16 m•s−1 and thrust coefficient of 0.56 in maximum are achieved in experiments.

The problem of flapping motion control of Micro Air Vehicles (MAVs) with flapping wings was studied in this paper. Based upon the knowledge of skeletal and muscular components of hummingbird, a dynamic model for flapping wing was developed. A control scheme inspired by human memory and learning concept was constructed for wing motion control of MAVs. The salient feature of the proposed control lies in its capabilities to improve the control performance by learning from experience and observation on its current and past behaviors, without the need for system dynamic information. Furthermore, the overall control scheme has a fairly simple structure and demands little online computations, making it attractive for real-time implementation on MAVs. Both theoretical analysis and computer simulation confirms its effectiveness.

In an attempt to realize a flapping wing micro-air vehicle with morphing wings, we report on improvements to our previous foldable artificial hind wing. Multiple hinges, which were implemented to mimic the bending zone of a beetle hind wing, were made of small composite hinge plates and tiny aluminum rivets. The buck-tails of rivets were flared after the hinge plates were assembled with the rivets so that the folding/unfolding motions could be completed in less time, and the straight shape of the artificial hind wing could be maintained after fabrication. Folding and unfolding actions were triggered by electrically-activated Shape Memory Alloy (SMA) wires. For wing folding, the actuation characteristics of the SMA wire actuator were modified through heat treatment. Through a series of flapping tests, we confirmed that the artificial wings did not fold back and arbitrarily fluctuate during the flapping motion.

This paper proposes a new adaptive linear domain system identification method for small unmanned aerial rotorcraft. By using the flash memory integrated into the micro guide navigation control module, system records the data sequences of flight tests as inputs (control signals for servos) and outputs (aircraft’s attitude and velocity information). After data preprocessing, the system constructs the horizontal and vertical dynamic model for the small unmanned aerial rotorcraft using adaptive genetic algorithm. The identified model is verified by a series of simulations and tests. Comparison between flight data and the one-step prediction data obtained from the identification model shows that the dynamic model has a good estimation for real unmanned aerial rotorcraft system. Based on the proposed dynamic model, the small unmanned aerial rotorcraft can perform hovering, turning, and straight flight tasks in real flight tests.

Nonverbal and noncontact behaviors play a significant role in allowing service robots to structure their interactions with humans. In this paper, a novel human-mimic mechanism of robot’s navigational skills was proposed for developing socially acceptable robotic etiquette. Based on the sociological and physiological concerns of interpersonal interactions in movement, several criteria in navigation were represented by constraints and incorporated into a unified probabilistic cost grid for safe motion planning and control, followed by an emphasis on the prediction of the human’s movement for adjusting the robot’s pre-collision navigational strategy. The human motion prediction utilizes a clustering-based algorithm for modeling humans’ indoor motion patterns as well as the combination of the long-term and short-term tendency prediction that takes into account the uncertainties of both velocity and heading direction. Both simulation and real-world experiments verified the effectiveness and reliability of the method to ensure human’s safety and comfort in navigation. A statistical user trials study was also given to validate the users’ favorable views of the human-friendly navigational behavior.

Two uncoupleable distributions, assigning missions to robots and allocating robots to home stations, accompany the use of mobile service robots in hospitals. In the given problem, two workload-related objectives and five groups of constraints are proposed. A bio-mimicked Binary Bees Algorithm (BBA) is introduced to solve this multiobjective multiconstraint combina-torial optimisation problem, in which constraint handling technique (Multiobjective Transformation, MOT), multiobjective evaluation method (nondominance selection), global search strategy (stochastic search in the variable space), local search strategy (Hamming neighbourhood exploitation), and post-processing means (feasibility selection) are the main issues. The BBA is then demonstrated with a case study, presenting the execution process of the algorithm, and also explaining the change of elite number in evolutionary process. Its optimisation result provides a group of feasible nondominated two-level distribution schemes.

We proposed a dynamic model identification and design of an H-Infinity (i.e. H∞) controller using a Lightweight Piezo-Composite Actuator (LIPCA). A second-order dynamic model was obtained by using input and output data, and applying an identification algorithm. The identified model coincides well with the real LIPCA. To reduce the resonating mode that is typical of piezoelectric actuators, a notch filter was used. A feedback controller using the H∞ control scheme was designed based on the identified dynamic model; thus, the LIPCA can be easily used as an actuator for biomemetic applications such as artificial muscles or macro/micro positioning in bioengineering. The control algorithm was implemented using a microprocessor, analog filters, and power amplifying drivers. Our simulation and experimental results demonstrate that the proposed control algorithm works well in real environment, providing robust performance and stability with uncertain disturbances.

This paper presents numerical investigations into a ridged surface whose design is inspired by the geometry of a Farrer’s scallop. The objective of the performed research is to assess if the proposed Bioinspired Ridged Surface (BRS) can potentially improve wear resistance of soil-engaging components used in agricultural machinery and to validate numerical simulations performed using software based on the Discrete Element Method (DEM). The wear performance of the BRS is experimentally determined and also compared with a conventional flat surface. Different size of soil particles and relative velocities between the abrasive sand and the testing surfaces are used. Comparative results show that the numerical simulations are in agreement with the experimental results and support the hypothesis that abrasive wear is greatly reduced by substituting a conventional flat surface with the BRS.

A concept of Specific Structure Efficiency (SSE) was proposed that can be used in the lightweight effect evaluation of structures. The main procedures of bionic structure design were introduced systematically. The parameter relationship between hollow stem of plant and the minimum weight was deduced in detail. In order to improve SSE of pylons, the structural char-acteristics of hollow stem were investigated and extracted. Bionic pylon was designed based on analogous biological structural characteristics. Using finite element method based simulation, the displacements and stresses in the bionic pylon were compared with those of the conventional pylon. Results show that the SSE of bionic pylon is improved obviously. Static, dynamic and electromagnetism tests were carried out on conventional and bionic pylons. The weight, stress, displacement and Radar Cross Section (RCS) of both pylons were measured. Experimental results illustrate that the SSE of bionic pylon is markedly improved that specific strength efficiency and specific stiffness efficiency of bionic pylon are increased by 52.9% and 43.6% respectively. The RCS of bionic pylon is reduced significantly.

Natural surfaces with super hydrophobic properties often have micro or hierarchical structures. In this paper, the wetting behaviours of a single droplet on biomimetic micro structured surfaces with different roughness parameters are investigated. A theoretical model is proposed to study wetting transitions. The results of theoretical analysis are compared with those of ex-periment indicating that the proposed model can effectively predict the wetting transition. Furthermore, a numerical simulation based on the meso scale Lattice Boltzmann Method (LBM) is performed to study dynamic contact angles, contact lines, and local velocity fields for the case that a droplet displays on the micro structured surface. A spherical water droplet with r_s = 15 μm falls down to a biomimetic square-post patterned surface under the force of gravity with an initial velocity of 0.01 m•s⁻¹ and an initial vertical distance of 20 μm from droplet centre to the top of pots. In spite of a higher initial velocity, the droplet can still stay in a Cassie state; moreover, it reaches an equilibrium state at t≈17.5 ms, when contact angle is 153.16? which is slightly lower than the prediction of Cassie-Baxter’s equation which gives θ_CB = 154.40?.

Based on auditory peripheral simulation model, a new Sound Quality Objective Evaluation (SQOE) method is presented, which can be used to model and analyze the impacts of head, shoulder and other parts of human body on sound wave trans-mission. This method employs the artificial head technique, in which the head related transfer function was taken into account to the outer ear simulation phase. First, a bionic artificial head was designed as the outer ear model with considering the outer sound field in view of theory and physical explanations. Then the auditory peripheral simulation model was built, which mimics the physiological functions of the human hearing, simulating the acoustic signal transfer process and conversion mechanisms from the free field to the peripheral auditory system. Finally, performance comparison was made between the proposed SQOE method and ArtemiS software, and the verifications of subjective and objective related analysis were made. Results show that the proposed method was economical, simple, and with good evaluation quality.

Due to our editing mistake, Fig. 9a in Ref. [1] was wrongly used. The correct Fig. 9 is given in the right.
We sincerely apologize to the authors and audience for this mistake.

Reference
[1]  Pfeiffer A T, Lee J S, Han J H, Baier H. Or-nithopter flight simulation based on flexible multi-body dynamics. Journal of Bionic Engineering, 2010, 7, 102–111.
doi: 10.1016/S1672-6529(09)60189-X

The research work in Ref. [1] received support from the Surgical Center Henri Mondor, University Paris 12, France. Therefore, we would like to publish the following acknowledgement:
This work was within the framework of an Erasmus student mobility at the Higher Institute of Bio Science, University Paris 12, France, which enabled the international collaboration with Faculty of Medical Bioengineering, University of Iasi, Romania. The experimental measurements and partial processing of the data presented in this article were obtained in the laboratory of Surgical Center Henri Mondor, University Paris 12, France. The authors wish to thank Professor Mustapha Zidi, Professor Eric Allaire, Dr Ingrid Masson, Dr Anissa Eddhahak and also for all re-searchers of the Surgical Center Henri Mondor for their help (expertise, material and technical supports) and coop-eration throughout this research.

Reference
[1] Mandru M, Ionescu C, Chirita M. Modelling mechanical properties in native and biomimetically formed vascular grafts. Journal of Bionic Engineering, 2009, 6, 371–377. doi: 10.1016/S1672-6529(08)60137-7