Recently, researchers have concentrated on studying ionic polymer metal composite (IPMC) artifcial muscle, which has numerous advantages including a relatively large strain under low input voltage, fexibility, high response, low noise, light weight, and high driving energy density. This paper reports recent developments in IPMC artifcial muscle, including improvement methods, modeling, and applications. Diferent types of IPMCs are described, along with various methods for overcoming some shortcomings, including improvement of Nafon matrix membranes, surface preparation of Nafon membranes, the choice of high-performing electrodes, and new electro-active polymers for enhancing the properties of IPMCs. IPMC models are also reviewed, providing theoretical guidance for studying the performance and applications of IPMCs. Successful applications such as bio-inspired robots, opto-mechatronic systems, and medical engineering are discussed.

Wingtip slots, where the outer primary feathers of birds split and spread vertically, are regarded as an evolved favorable feature that could eff ectively improve their aerodynamic performance. They have inspired many to perform experiments and simulations as well as to relate their results to aircraft design. This paper aims to provide guidance for the research on the aerodynamic mechanism of wingtip slots. Following a review of previous wingtip slot research, four imperfections are put forward: vacancies in research content, inconsistencies in research conclusions, limitations of early research methods, and shortage of the aerodynamic mechanism analysis. On this basis, further explorations and expansion of the infl uence factors for steady state are needed; more attention should be poured into the application of fl ow fi eld integration method to decompose drag, and evaluation of variation in induced drag seems a more rational choice. Geometric and kinematic parameters of wingtip slot structure in the unsteady state, as well as the fl exibility of wingtips, should be taken into account. As for the aerodynamic mechanism of wingtip slots, the emphasis can be placed on the study of the formation, development, and evolution of wingtip vortices on slotted wings. Besides, some research strategies and feasibility analyses are proposed for each part of the research.

Feline animals can run quickly using spinal joints as well as the joints that make up their four legs. This paper describes the development of a quadruped robot including a spinal joint that biomimics feline animals. The developed robot platform consists of four legs with a double 4-bar linkage type and one simplifi ed rotary joint. In addition, Q-learning, a type of machine learning, was used to fi nd the optimal motion profi le of the spinal joint. The bounding gait was implemented on the robot system using the motion profi le of the spinal joint, and it was confi rmed that using the spinal joint can achieve a faster Center of Mass (CoM) forward speed than not using the spinal joint. Although the motion profi le obtained through Q-learning did not exactly match the spinal angle of a feline animal, which is more multiarticular than that of the developed robot, the tendency of the actual feline animal spinal motion profi le, which is sinusoidal, was similar. 

The lack of autonomous take-off and landing capabilities of bird-like fl apping-wing aerial vehicles (BFAVs) seriously restricts their further development and application. Thus, combined with the current research results on the autonomous take-off and landing technology of unmanned aerial vehicles, four types of technologies are studied, including jumping take-off and landing technology, taxiing take-off and landing technology, gliding take-off and landing technology, and vertical take-off and landing (VTOL) technology. Based on the analytic hierarchy process (AHP)–comprehensive evaluation method, a fuzzy comprehensive evaluation model for the autonomous take-off and landing scheme of a BFAV is established, and four schemes are evaluated concretely. The results show that under the existing technical conditions, the hybrid layout VTOL scheme is the best. Furthermore, the detailed design and development of the prototype of a BFAV with a four-rotor hybrid layout are carried out, and the vehicle performance is tested. The results prove that through the four-rotor hybrid layout design, the BFAV has good autonomous take-off and landing abilities. The power consumption analysis shows that for a fi xed-point reconnaissance mission, when the mission radius is less than 3.38 km, the VTOL type exhibits longer mission duration than the hand-launched type. 

Energy consumption and acoustic noise can be signifi cantly reduced through perching in the sustained fl ights of small Unmanned Aerial Vehicles (UAVs). However, the existing fl ying perching robots lack good adaptability or loading capacity in unstructured environments. Aiming at solving these problems, a deformable UAV perching mechanism with strong adaptability and high loading capacity, which is inspired by the structure and movements of birds' feet, is presented in this paper. Three elastic toes, an inverted crank slider mechanism used to realize the opening and closing movements, and a gear mechanism used to deform between two confi gurations are included in this mechanism. With experiments on its performance towards diff erent objects, Results show that it can perch on various objects reliably, and its payload is more than 15 times its weight. By integrating it with a quadcopter, it can perch on diff erent types of targets in outdoor environments, such as tree branches, cables, eaves, and spherical lamps. In addition, the energy consumption of the UAV perching system when perching on objects can be reduced to 0.015 times that of hovering. 

With the development of intelligent bionic robots and the improvement of military application, a single robot cannot meet the requirements of the tasks of the current era. The more complex tasks require not only that the robot be able to pass through the fi eld barriers and the amphibious environment, but also that the robot be able to collaborate in a multi-robot system. Consequently, research on the multi-robot control system of spherical amphibious robots is very important. Presently, the main research on amphibious robots is to improve the functions of a single robot, in the absence of the study of the multi-robot control system. Existing systems primarily use a centralized control methodology. Although the transfer of central node can be achieved, there is still a problem of Byzantine fault tolerance in military applications, that is, when the amphibious multi-robot system is invaded by the enemy. The central node may not only fail to accomplish the task, but also lose control of other robots, with severe consequences. To solve the above problems, this paper proposed a decentralized method of spherical amphibious multi-robot control system based on blockchain technology. First, the point-to-point information network based on long range radio technology of low power wide area network was set up, we designed the blockchain system for embedded application environment and the decentralized hardware and software architecture of multi-robot control system. On this basis, the consensus plugin, smart contract and decentralized multi-robot control algorithm were designed to achieve decentralization. The experimental results of consensus of spherical amphibious multi-robot showed the eff ectiveness of the decentralization. 

Rehabilitation is the most eff ective way to reduce motor impairments in post-stroke patients. This process demands several hours with a specialized therapist. Given resources and personnel shortages, the literature reports a high interest in robotic assisted rehabilitation solutions. Recently, cable-driven robotic architectures are attracting signifi cant research interest for post-stroke rehabilitation. However, the existing cable-driven robots are mostly unilateral devices allowing the rehabilitation only of the most aff ected limb. This leaves unaddressed the rehabilitation of bimanual activities, which are predominant within the common Activities of Daily Living (ADL). Thus, this paper presents a specifi c novel design to achieve bimanual rehabilitation tasks that has been named as BiCAR robot. Specifi cally, this paper provides a full insight on the BiCAR system as well as on its dedicated developed software BiEval. In particular, BiEval software has been developed as based on a serious game strategy and a virtual reality environment to track the patient exercising duration, motion ranges, speeds, and forces over time for achieving a quantitative assessment of the rehabilitation progress. Finally, the paper presents the BiCAR/ BiEval capabilities by referring to a pilot Randomized Controlled Trial (RCT). The clinical trials have been used to validate the BiCAR/BiEval in terms of engineering feasibility and user acceptance to achieve an innovative cost-oriented integrated hardware/software device for the bimanual assistive rehabilitation of post-stroke patients. 

Lack of temperature sensation of myoelectric prosthetic hand limits the daily activities of amputees. To this end, a noninvasive temperature sensation method is proposed to train amputees to sense temperature with psychophysical sensory substitution. In this study, 22 healthy participants took part besides 5 amputee participants. The duration time of the study was 31 days with fi ve test steps according to the Leitner technique. An adjustable temperature mug and a Peltier were used to change the temperature of the water/phantom digits to induce temperature to participants. Also, to isolate the surroundings and show colors, a Virtual Reality (VR) glass was employed. The statistical results conducted are based on the response of participants with questionnaire method. Using Chi-square tests, it is concluded that participants answer the experiment signifi cantly correctly using the Leitner technique ( P value < 0.05). Also, by applying the “Repeated Measures ANOVA”, it is noticed that the time of numbness felt by participants had signifi cant ( P value < 0.001) diff erence. Participants could remember lowest and highest temperatures signifi cantly better than other temperatures ( P value < 0.001); furthermore, the well-trained amputee participant practically using the prosthesis with 72.58% could identify object’s temperature with only once time experimenting the color temperature.  

Bending Pneumatic Artifi cial Muscles (PAMs) are particularly attractive and extensively applied to the soft grasper, snakelike robot, etc. To extend the application of PAMs, we fabricate a Multi-directional Bending Pneumatic Artifi cial Muscle (MBPAM) that can bend in eight directions by changing the pressurized chambers. The maximum bending angle and output force are 151° and 0.643 N under the pressure of 100 kPa, respectively. Additionally, the Finite Element Model (FEM) is established to further investigate the performance. The experimental and numerical results demonstrate the nonlinear relationship between the pressure and the bending angle and output force. Moreover, the eff ects of parameters on the performance are studied with the validated FEM. The results reveal that the amplitude of waves and the thickness of the base layer can be optimized. Thus, multi-objective optimization is performed to improve the bending performance of the MBPAM. The optimization results indicate that the output force can be increased by 7.8% with the identical bending angle of the initial design, while the bending angle can be improved by 8.6% with the same output force. Finally, the grasp tests demonstrate the grip capability of the soft four-fi nger gripper and display the application prospect of the MBPAM in soft robots. 

 The study aimed to develop effi cient techniques with diff erent novel graft structures to enhance the treatment of acetabular bone defi ciency. The inhomogeneous material properties Finite Element Analysis (FEA) model was reconstructed according to computed tomography images based on a healthy patient without any peri-acetabular bony defect according to the American Academy of Orthopedic Surgeons (AAOS). The FEA model of acetabular bone defi ciency was performed to simulate and evaluate the mechanical performances of the grafts in diff erent geometric structures, with the use of fi xation implants (screws), along with the stress distribution and the relative micromotion of graft models. The stress distribution mainly concentrated on the region of contact of the screws and superolateral bone. Among the diff erent structures, the mortise–tenone structure provided better relative micromotion, with suitable biomechanical property even without the use of screws. The novel grafting structures could provide suffi cient biomechanical stability and bone remodeling, and the mortise–tenone structure is the optimal treatment option for acetabulum reconstruction. 

Nanofi bers (NFs) have been widely used in tissue engineering such as wound healing. In this work, the antibacterial ZnO quantum dots (ZnO QDs) have been incorporated into the biocompatible poly (ε-caprolactone)/collagen (PCL/Col) fi brous scaff olds for wound healing. The as-fabricated PCL-Col/ZnO fi brous scaff olds exhibited good swelling, antibacterial activity, and biodegradation behaviors, which were benefi cial for the applications as a wound dressing. Moreover, the PCL-Col/ZnO fi brous scaff olds showed excellent cytocompatibility for promoting cell proliferation. The resultant PCL-Col/ZnO fi brous scaff olds containing vascular endothelial growth factor (VEGF) also exhibited promoted wound-healing eff ect through promoting expression of transforming growth factor-β (TGF-β) and the vascular factor (CD31) in tissues in the early stages of wound healing. This new electrospun fi brous scaff olds with wound-healing promotion and antibacterial property should be convenient for treating wound healing. 

Surface treatments applied to titanium and its alloys for implant applications are important for the development of bio properties. In this study, first an oxide layer was formed on the surface of the titanium plate by micro arc oxidation, and then both calcium phosphate and calcium phosphate/chitosan accumulation were performed for different samples by the sol–gel method. FE-SEM/EDS examinations, XRD, FTIR and thermal analysis were performed for these micro arc-oxidized, calcium phosphate-coated and calcium phosphate/chitosan-coated surfaces. The surface roughnesses for these surfaces were measured between 10 μm and 100 μm, suitable for bone development on the surface. The effect of chitosan addition on the calcium phosphate-coated surface on apatite formation ability and antibacterial properties was investigated. Although the addition of chitosan slows down the formation of apatite, it ensured that the coating had antibacterial properties. The calcium phosphate/chitosan biocomposite obtained can be recommended for dental and orthopedic implants.

Natural biopolymers have excellent biocompatibility and biodegradability; they can be used as biomedical materials for wound healing. In this work, the Silk Fibroin (SF) and κ-carrageenan (κ-Car) composite films containing Zinc-doped Bioactive Glass (ZBG) have been fabricated for wound closure applications. The as-fabricated SF–κ-Car/ZBG composite films have excellent stretchability and foldability, which facilitates them for application as wound dressing. They also exhibit excellent hydrophilicity and water-absorption capacity, which can effectively absorb wound exudate and keep the wound sites under moist state. In addition, the composite films have a good antibacterial effect against S. aureus and E. coli in vitro, which can reduce the risk of wound infection. Their excellent cell compatibility is confi rmed by the CCK-8 assay. The strong vascular proliferation and wound regeneration are found in SF–κ-Car/ZBG composite films on a mouse skin wound model. The SF–κCar/ZBG composite films can inhibit the secretion of inflammatory factors, and stimulate the production of vascular factors and collagen fibers. The results derived from the performed investigations revealed that the SF–κ-Car/ZBG composite films are a promising candidate dressing for wound healing applications.

Significant progress has been made on understanding the critical role of organic components in directing the collagen mineralization. We hypothesize that the inorganic trace elements might also play important role in the mineralization of collagenous matrix. To this aim, we systematically compared the in-vitro biomineralization behaviors of gelatin, gelatin-HA and gelatin-SiHA electrospun membranes. The results indicated that the presence of Si ions played a striking influence on the nucleation behaviors and mineralized structures. The gelatin-SiHA samples demonstrated more homogeneous nucleation within the gelatin fiber and growth along the fiber direction, in comparison with the heterogeneous nucleation and growth of spherulitic clusters on top of the nanofiber surface, i.e. extrafibrillar mineralization. The likely shift of the nucleation mode to the intrafibrillar mineralization in the presence of Si ions led to good alignment of apatite c -axis with the long axis of the nanofi ber, resulting in a mineralization process and microstructure that were closer to those in natural bone. Cellular response analysis indicated that Si incorporation improved the MSC attachment and cytoskeleton organization. Such findings might have important implication in both understanding the complex mechanisms involved in collagen mineralization and optimal designing of advanced bio-inspired materials with potential superior mechanical and biological properties.

Polylactic acid (PLA) possesses good mechanical and biodegradability properties which make it a suitable material for polymer composites whereas brittleness and high costs limit its utilization in various applications. The reinforcement of natural fibres with biopolymers has been formed to be an efficient technique to develop composites having the ability to be fully biodegradable. This study concerns with the incorporation of various percentages of untreated and alkali-treated Coir Fibres (CF) and pineapple leaf fibres (PALF) in PLA biocomposites and characterizations of flexural, morphological and dynamic mechanical properties. Flexural properties showed that the treated C1P1 hybrid composites (C1P1A) displayed highest flexural strength (35.81 MPa) and modulus (5.28 GPa) among all hybrid biocomposites. Scanning Electron Microscopy (SEM) revealed a behaviour of fibre-matrix adhesion in untreated treated biocomposites. SEM observation revealed good dispersion of the fillers in PLA. Dynamic mechanical analysis revealed that C1P1A showed highest glass transition temperature ( Tg ) and storage modulus ( E ′) while untreated C3P7 displayed the least Tg and E ?. Overall findings showed that alkali-treated hybrid biocomposites (CF/PALF/PLA) especially C1P1A have improved flexural properties, dynamic and morphological properties over untreated biocomposites. Success of these findings will provide attracting consideration of these hybrid biocomposites for various lightweight uses in a broad selection of industrial applications such as biomedical sectors, automobile, construction, electronics equipment, and hardware tools. 

The anthropomorphic intelligence of autonomous driving has been a research hotspot in the world. However, current studies have not been able to reveal the mechanism of drivers' natural driving behaviors. Therefore, this thesis starts from the perspective of cognitive decision-making in the human brain, which is inspired by the regulation of dopamine feedback in the basal ganglia, and a reinforcement learning model is established to solve the brain-like intelligent decision-making problems in the process of interacting with the environment. In this thesis, first, a detailed bionic mechanism architecture based on basal ganglia was proposed by the consideration and analysis of its feedback regulation mechanism; second, the above mechanism was transformed into a reinforcement Q -learning model, so as to implement the learning and adaptation abilities of an intelligent vehicle for brain-like intelligent decision-making during car-following; finally, the feasibility and effectiveness of the proposed method were verified by the simulations and real vehicle tests. 

Image fusion technology is the basis of computer vision task, but information is easily affected by noise during transmission. In this paper, an Improved Pigeon-Inspired Optimization (IPIO) is proposed, and used for multi-focus noisy image fusion by combining with the boundary handling of the convolutional sparse representation. By two-scale image decomposition, the input image is decomposed into base layer and detail layer. For the base layer, IPIO algorithm is used to obtain the optimized weights for fusion, whose value range is gained by fusing the edge information. Besides, the global information entropy is used as the fitness index of the IPIO, which has high efficiency especially for discrete optimization problems. For the detail layer, the fusion of its coefficients is completed by performing boundary processing when solving the convolution sparse representation in the frequency domain. The sum of the above base and detail layers is as the final fused image. Experimental results show that the proposed algorithm has a better fusion effect compared with the recent algorithms. 

The research field of legged robots has always relied on the bionic robotic research, especially in locomotion regulating approaches, such as foot trajectory planning, body stability regulating and energy efficiency prompting. Minimizing energy consumption and keeping the stability of body are considered as two main characteristics of human walking. This work devotes to develop an energy-efficient gait control method for electrical quadruped robots with the inspiration of human walking pattern. Based on the mechanical power distribution trend, an efficient humanoid power redistribution approach is established for the electrical quadruped robot. Through studying the walking behavior acted by mankind, such as the foot trajectory and change of mechanical power, we believe that the proposed controller which includes the bionic foot movement trajectory and humanoid power redistribution method can be implemented on the electrical quadruped robot prototype. The stability and energy efficiency of the proposed controller are tested by the simulation and the single-leg prototype experiment. The results verify that the humanoid power planning approach can improve the energy efficiency of the electrical quadruped robots.