Applied Bionics and Biomechanics

Effective workflow scheduling in cloud computing is still a challenging problem as incoming workflows to cloud console having variable task processing capacities and dependencies as they will arise from various heterogeneous resources. Ineffective scheduling of workflows to virtual resources in cloud environment leads to violations in service level agreements and high energy consumption, which impacts the quality of service of cloud provider. Many existing authors developed workflow scheduling algorithms addressing operational costs and makespan, but still, there is a provision to improve the scheduling process in cloud paradigm as it is an nondeterministic polynomial-hard problem. Therefore, in this research, a task-prioritized multiobjective workflow scheduling algorithm was developed by using cuckoo search algorithm to precisely map incoming workflows onto corresponding virtual resources. Extensive simulations were carried out on workflowsim using randomly generated workflows from simulator. For evaluating the efficacy of our proposed approach, we compared our proposed scheduling algorithm with existing approaches, i.e., Max–Min, first come first serve, minimum completion time, Min–Min, resource allocation security with efficient task scheduling in cloud computing-hybrid machine learning, and Round Robin. Our proposed approach is outperformed by minimizing energy consumption by 15% and reducing service level agreement violations by 22%.

The demand for high-performance underwater thrusters in marine engineering is increasing. The concealed, mobile, and efficient underwater ability of fish provides many directions for research. The black ghost knifefish uses only wavy ventral fins to swim and can hover and roll in the water. Based on the physiological and morphological characteristics of the black ghost knifefish, we explored the structure and movement mode of the ventral fin, so as to establish a two-degree of freedom (2-DOF) structural model and kinematic model. We reveal the motion mechanism of the undulating fin propulsion through the constructed model and computational fluid dynamics. It is found that when the fin surface fluctuates, a pair of vortices with opposite directions will be formed on the concave side of the fin surface. These vortices will produce a central jet on the fin surface, provide a reverse impulse for the ventral fin, and make the fin obtain power. In addition, we found that the propulsive force of the ribbon fin along the body direction is positively correlated with the swing amplitude and frequency of the fin movement, and the propulsive torque of the ribbon fin to realize the maneuvering movement increases first and then decreases with the increase of the torsion angle. The research on the structure and motion mechanism of the ribbon fin of the black ghost knifefish provides a basis for the development of a bionic prototype of multi-DOF motion and the control strategy of high-mobility motion.

Soft actuators have great potential in human–machine interaction and soft robotics innovation. Origami exhibiting outstanding structural and topological properties can be a paradigm for people to design various soft robots. Inspired by origami, we have previously designed a telescopic actuator with excellent performance, mainly large force output, and two-way working. Although significant advances have been made in soft bending actuators, their further study and applications are limited due to small force output in a monotonous work style. In this paper, we design a series of novel bending actuators that inherit our prior telescopic actuator’s excellent characteristics to diversify soft actuators’ motion forms. Several actuators of different sizes are fabricated using three different materials and evaluated on a designed test platform. The test results show that actuators of different sizes using different materials perform differently. Namely, the maximum tip force produced by an actuator reaches 9.6 N, and the maximum bending angle is achieved by another one up to 138°. Finally, extensive demonstrations and tests include wriggling, gripping, and bidirectional motion in the water. They show our flexible bending actuators’ distinguishing characteristics of large output force and two-way working.

This study aimed to design a three-dimensional (3D) guide plate using computer-aided design and a 3D printing system for precise implantation of microimplants for orthodontic treatment and investigate the accuracy and feasibility of a 3D guide plate in clinical practice. A total of 30 microimplants were placed in 15 patients in the Department of Stomatology, Affiliated Hospital of Jiangnan University. Before surgery, DICOM data from cone-beam computed tomography (CBCT) scans and STereoLithography data from the 3D model scan were imported to 3Shape Dental System. Data fitting and matching were performed, and 3D guide plates were designed primarily focusing on the thickness of guide plates, amount of concave compensation, and dimensions of the ring. Assist implantation method was used to place the microimplants, and postoperative CBCT images were used to evaluate the position and implantation angle. The feasibility of placing microimplants and precise implantation guided by the 3D guide plate. CBCT data before and after the placement of microimplants were compared. Regarding the secure positioning of microimplants based on CBCT data, 26 implants were categorized as Grade i, four as Grade ii, and none as Grade iii. No loosening of microimplants 1 and 3 months after surgery was reported. The implantation of microimplants is more accurate under the guidance of a 3D guide plate. This technology can achieve accurate implant positioning, thus ensuring safety, stability, and improved success rates after implantation.

A flexible pneumatic wrist with spatial position maintenance function is developed in this paper to settle the matter of insufficient flexibility of the robot wrist and self-braking technology. The wrist is made up of four artificial muscles and a pneumatic spherical brake in parallel, with 2 degrees of freedom. The wrist can realize multidirectional bending and adjust the wrist damping and braking in real time as required to achieve position maintenance. The theoretical model of the wrist bending angle is built based on torque balance. The variation of wrist bending angle and motion trajectory with air pressure is acquired through experiments. Simultaneously, the validity of the bending angle theoretical model is verified experimentally. A normally open pneumatic spherical brake is developed, and the mathematical model of braking torque is built and experimentally validated. Using a 3D dynamic capture system to compare the dynamic characteristics of the wrist under different excitation signals and different damping conditions. The experimental results reveal that the wrist has good flexibility and can achieve the functions of human hand pitch and yaw. The bending angle is 20.72° at 0.34 MPa. The pneumatic spherical brake has the function of spatial multidirection braking, and the braking force is adjustable. The maximum braking torque can reach 1.4 N m at 0.35 MPa.

The study aimed to compare the technique of normal gait with the Nordic walking (NW) gait with classical and mechatronic poles in patients with ischemic heart disease. It was assumed that equipping classical NW poles with sensors enabling biomechanical gait analysis would not cause a change in the gait pattern. The study involved 12 men suffering from ischemic heart disease (age: 66.2 ± 5.2 years, body height: 173.8 ± 6.74 cm; body mass: 87.3 ± 10.89 kg; disease duration: 12.2 ± 7.5 years). The MyoMOTION 3D inertial motion capture system (Noraxon Inc., Scottsdale, AZ, USA) was used to collect biomechanical variables of gait (spatiotemporal and kinematic parameters). The subject’s task was to cover the 100 m distance with three types of gait-walking without poles (normal gait), walking with classical poles to NW, and walking with mechatronic poles from the so-called preferred velocity. Parameters were measured on the right and left sides of the body. The data were analyzed using two-way repeated measures analysis of variance with the between-subject factor “body side.” Friedman’s test was used when necessary. For most kinematic parameters, with the exception of knee flexion–extension () and shoulder flexion–extension (), significant differences were found between normal and walking with poles for both the left and right side of the body and no differences due to the type of pole. Differences between the left and right movement ranges were identified only for the ankle inversion–eversion parameter (gait without poles ; gait with classical poles ). In the case of spatiotemporal parameters, a reduction in the cadence step value using mechatronic poles and the stance phase using classical poles compared to normal walking was observed. There was also an increase in the values for step length and step time regardless of the type of poles, stride length, and swing phase when using classical poles and stride time when using mechatronic poles. The differences between the right and left sides of the measurement occurred when walking with both types of poles for single support (gait with classical poles ; gait with mechatronic poles ), stance phase (gait with classical poles ; gait with mechatronic poles ) and swing phase (gait with classical poles ; gait with mechatronic poles ). Mechatronic poles can be used in the study of the biomechanics of gait in real-time with feedback on its regularity because no statistically significant differences were found between the NW gait with classical and mechatronic poles in the studied men with ischemic heart disease.