Applied Mechanics and Materials Vol. 461

Abstract: A bionic elbow joint driven by motor is lack of flexibility. So a good option is to improve the flexible and power density ratio. This paper has designed a 3-DOF bionic elbow joint based on pneumatic artificial muscle, and the simulation and forward kinematics analysis have been done. The simulation results show that the structure scheme is feasible, and the movement is smooth. This structure can improve the generalization of the bionic joint and then lay a foundation in the serialization and standardization of the transmission part.

Abstract: The wearable assistive and rehabilitative leg is a complex mechanical device mounted with the underactuated joints based on the bionic mechanism. This device can ameliorate the movement function of the nerve and muscle system of the lower extremity. By applying the bionic control strategy and exerting force on the lower extremity of patients, the walking gait of normal human being can be simulated. The patients with leg deformity who need to be remedied can benefit from this method. The expense on medical treatment can be considerably reduced by this kind of device, which alleviates the burden on family and society economically. The walking stability controller is designed for researching the biped robots in 3D ( three-dimensional) space. By constructing the almost-cyclic Lagrange function, the biped robot dynamic system is decoupled into sagittal and lateral portions. Then the potential energy shaping and kinetic energy shaping controller is designed for the sagittal portion of under-actuated robot in 2D space , so that the stable walking gait and bionic characteristic gait can be obtained; the output zero dynamic controller is applied to control the lateral counterpart, which satisfies the dynamic decoupling conditions of the system. The simulation results show that the proposed method is effective.

Abstract: Many studies have investigated the relationship between surface EMG and joint torque. Most studies have used EMG amplitude to assess elbow joint torque with dynamic models. In this paper, we used signal length and normalized zero crossing rates together with EMG amplitude to assess elbow joint torque with EMG-to-Torque models. We compared the performance of single feature EMG-to-Torque models and multi-feature EMG-to-Torque models by calculating the RMS error between estimated torque and true torque. The results show that multi-channel and multiple feature combination is superior to that of the single feature only. In this study, surface EMG signals were recorded from biceps and triceps muscles of 15 subjects. Single-channel and single feature linear model, multi-channel and single-feature model, multi-channel and single-feature model, multi-channel and multi-feature linear model were all used to assess elbow joint torque. The lowest RMS error is 7.6% achieved by four-channel multi-feature 18-order linear model.

Abstract: Affective computing is an indispensable aspect in harmonious human-computer interaction and artificial intelligence. Making computers have the ability of generating emotions is a challenging task of affective computing. Affective Computing and Artificial Psychology are new research fields that involve computer and emotions, they have the same key research aspect, affective modeling. The paper introduces the basic affective elements, and the representation of affections in a computer. And we will describe an emotion generation model for a multimodal virtual human. The relationship among the emotion, mood and personality are discussed, and the PAD emotion space is used to define the emotion and the mood. We obtain the strength information of each expression component through fuzzy recognition of facial expressions based on Ekman six expression classifications, and take this information as a signal motivating emotion under the intensity-based affective model. Finally, a 3D virtual Human head with facial expressions is designed to show the emotion generation outputs. Experimental results demonstrate that the emotion generation intensity-based model works effectively and meets the basic principle of human emotion generation.

Abstract: This paper introduced current typical available dental articular simulators that could simulate border movements of the mandible in harmony with the patients masticatory system. Mechanical and virtual simulators are reviewed, and their abilities to adjust and duplicate the patients specific condylar movements are stated in comparison. This paper provides a fundamental methodology research for developing a new effective biologically inspired simulator which can be accurately represented occlusal relationships in the future.

Abstract: A Multitude of different prosthesis designs have been developed for restoring transtibial and transfemoral amputees’ mobility.But yet,most of them are considered as passive devices.Therefore,more and more researchers develop bionic controller that simulate the biological certral pattern generator,namely CPG.This paper presents a new control method using bipedal robotics technology and bio-inspiration based on CPG.To begin with,we present the fundamental measurement of human walking gait and the device mainly includes three-dimensional camera system,digitized movements analyzer and so on.We choose hopf oscillators as CPG simulation unit.And after several tests,five oscillators are just right for a single joint.We change the simple hopf oscillator equation.Thus corresponding to the knee,CPG modeling finally generate actual human angle curve.Then we define learning equation as learning a given periodic signal.By trying different values of the different parameters we obtain the desired walking curve of knee joint.Using the obtained parameters,learning equation reproduce knee joint angle.According to the signal of the accelerometer that placed in the hip to adjust learning equation,so the amputees can easily control the speed of walking.Matlab simulation results show that the same trend with changes in human joint angles,which lay a good foundation for the control of active prostheses.

Abstract: Geckos are able to crawl or even run on the wall and the ceiling, but have to be in the face of the risk of falling down due to fatigue or a slip. From the opinion of natural selection and evolution, geckos must possess certain characteristics to prevent themselves especially their head from injury caused by impacting the ground. In this study, we looked into geckos brain to investigate their internal environment and structure, using magnetic resonance imaging (MRI). By means of volume integrating the brain parenchyma and the cerebrospinal fluid separately, we found that the intracalvarium is full of the cerebrospinal fluid, up to 45% in volume. And the brain parenchyma is surrounded by the cerebrospinal fluid. This implies the self-protection function of geckos brain appropriate to geckos behavior. The cerebrospinal fluid plays a buffer role in the risk of falling down to protect brain.

Abstract: Under the perspectives of network science and systems biology, the characterizations of transcriptional regulatory networks (TRNs) beyond the context of model organisms have been studied extensively. However, little is still known about the structure and functionality of TRNs that control metabolic physiological processes. In this study, we present a newly version of the TRN of E.coli controlling metabolism based on functional annotations from GeneProtEC and Gene Ontology (GO). We also present an exhaustive topological analysis of the metabolic transcriptional regulatory network (MTRN), focusing on the main statistical characterization describing the topological structure and the comparison with TRN. From the results in this paper we infer that TRN and MTRN have very similar characteristic distribution.

Abstract: Tuning properties of neurons, which represent how information is encoded in neural firing, are well accepted as time variant. For a steady-performed brain machine interface (BMI), the decoding algorithm should be able to catch this change in time. Unfortunately, an assumption-less tuning property is too complicate to trace. Simplifying the tuning curve to linear or exponential one may lose important information. We propose to approximate the tuning curve with multiple Gaussian functions, and modeled the non-stationary tuning curves by the changes on the Gaussian parameters. Applied on in vivo neural data when the monkey is performing a 2-dimension tracking task, we found the non-stationary tuning properties can be tracked by the changes on parameters of Gaussian components, which greatly decreases the number of parameters need to be observed. Following this idea, we can design an adaptive method by updating parameters of tuning model.

Abstract: Falls are the second leading cause of unintentional injury deaths worldwide, so how to prevent falls has become a safety and security problem for elderly people. At present, because the sensing modules of most fall alarm devices generally only integrate the single 3-axis accelerometer, so the measured accuracy of sensing signals is limited. It results in that these devices can only achieve the alarm of post-fall detection but not the early pre-impact fall recognition in real fall applications. Therefore, this paper aimed to develop an early pre-impact fall alarm system based on high-precision inertial sensing units. A multi-modality sensing module embedded fall detection algorithm was developed for early pre-impact fall detection. The module included a 3-axis accelerometer, a 3-axis gyroscope and a 3-axis magnetometer, which could arouse the information of early pre-impact fall warning by a buzzer and a vibrator. Total 81 times fall experiments from 9 healthy subjects were conducted in simulated fall conditions. By combination of the early warning threshold algorithm, the result shows that the detection sensitivity can achieve 98.61% with a specificity of 98.61%, and the average pre-impact lead time is 300ms. In the future, GPS, GSM electronic modules and wearable protected airbag will be embedded in the system, which will enhance the real-time fall protection and timely immediate aid immensely for the elderly people.