Nonlinear regression equations for segmental mass-inertial characteristics of Korean adults estimated using three-dimensional range scan data

Human modeling and the biomechanical analysis of human movement require the accurate estimation of body segment parameters for various populations and individuals. In this study, the body characteristics of adult Koreans were investigated using three-dimensional range scan data for 40 males and 40 females aged between 18 and 59 years obtained from the SizeKorea anthropometric database. Each subject was divided into 16 segments, and the mass-inertial parameters of each segment were calculated under the assumption of a uniform density distribution for the segment. The length and at least one circumference of each segment were determined from the scan data for that segment. Nonlinear regression equations were then derived based on the segment lengths and circumferences. The body segment parameters of Korean adults can be estimated using these equations if the required dimensions are measured directly or derived from an anthropometric database.     

Recursive Formalism with a Minimal Dynamic Parameterization for the Identification and Simulation of Multibody Systems. Application to the Human Body

This paper presents a multibody formalism using a minimal set of dynamicalparameters, based on the barycentric approach. Using relative jointcoordinates, we show that it is possible to generate recursively the inverseand direct dynamics in terms of this minimal set, rather than using theclassical ones (mass, centre of mass and inertia matrix). More thanproviding a very compact scheme in terms of flops, the proposed formalism,in which the independent dynamical parameters appear linearly, is a precioustool for identification purpose; indeed, the recursive nature of theformalism and its symbolic implementation allows us to deal with very large models, such as the human body for instance. The approach is then applied to the identification of some of the human body's dynamical parameters, on the basis of a trajectory issuing from a volleyball typical movement.     

A research on the body center of mass of chinese adults

The body center of mass (COM) plays a prominent role in occupational ergonomics. By analyzing the body dimension parameters, anthropometric inertia parameters, i.e. mass, COM location and inertia, can be determined. The parameters can then be applied in diverse areas such as developing an artificial limb for the physically disabled, designing protective appliances and wear for laborers, designing an ejection seat for a fighter jet and performing motion analysis of astronauts.This study measures 15 kinds of basic segment parameters in the human body for Chinese adults. Computer tomography and image processing are adopted in the measurements. Based on the body dimension parameters, a mathematical model is also derived/presented to estimate the segment mass and segment COM of Chinese adults. The data accuracy is quite remarkable.Relevance to industryThe results obtained in this study can be applied to the designs of safe protection devices and appliances in the workplace, and the development of artificial limbs for osteological and rehabilitation medicine.     

Investigation into the mass distribution properties of the human body and its segments

A series of studies was conducted to develop information about mass distribution characteristics of the living human body and its segments, and to establish a reliable means for estimating these properties from easily measured body dimensions. While investigators over the years have established a number of laborious methods for determining body mass and moments of inertia of individuals, comparable data for segments of the body have till recently been available only through the study of cadavers. The use of stereophotography now makes possible the segmentation of living subjects and provides a means for measuring mass distribution properties on body segments as well as on the total body.

In the studies described here investigators combined stereophotometric and anthropometric techniques to measure 31 male subjects and 46 female subjects. Bodies were photographically segmented and their volumes, centres of volume and principal moments of inertia established stereophotometrically. The principal axes of inertia were established with reference to anatomical axis systems based on easily located landmarks. A number of body size variables were measured anthropometrically and multiple regression equations were devised for the total body and for each segment using the most highly correlated variables on each segment, and stature and weight for determining volume and principal moments of inertia. It is anticipated that these data will be useful in the design of anthropomorphic test devices used in safety research, design and performance evaluation of safety restraint systems and development of body prostheses.     

A clear description of system dynamics through the physical parameters and generalized coordinates

A new formalism of the equations of motion for a general system with dynamic behavior is developed and presented in this paper. Despite the tremendous progression made in the field of multibody dynamics, the following question was raised: how are the physical parameters of a system involved in the inertia, centrifugal, and Coriolis terms? Generally expressed under a compact formulation, the equations of motion are nevertheless formulated using recursive processes or require heavy intermediate calculations. Accordingly, it can be concluded that the complete comprehension of the equations of motion has not been reached. Therefore, they have to be formulated in a more suitable way respecting various constraints simultaneously. These constraints were defined as follows: the equations of motion need to (i) be analytical, (ii) be direct, (iii) highlight clearly how the system’s structural parameters are involved in the equations, (iv) be compact. Thus, reaching a formulation considering the previous constraints could allow for a better understanding of multibody dynamics. Based on the equations of Newton–Euler, a new formalism that satisfies these constraints has been developed. The first form was reached that provides a compact expression and highlights directly the relation between the structural parameters and the dynamics of a system. In addition, to obtain the direct relation between the system’s structural parameters and each term due to the dynamic and environment forces, the second form is generated. In this framework, the analytical expressions of the inertia tensor, the torques due to the centrifugal and Coriolis forces of a general multibody system are exposed.     

Derivation and analysis of a dynamic model of a robotic manipulator on a moving base

A dynamic model of a robotic manipulator mounted on a moving base is derived using the Euler-Lagrange approach. It is assumed that the base inertia is large enough not to be influenced by the manipulator motion and therefore can be treated as a time-varying parameter in the dynamic equations. The presented derivation is applied to a Mitsubishi PA10-6CE robotic manipulator mounted on a 2-DOF platform. The model is analysed by comparing simple closed-loop control results of the simulated model with experimental data from the manipulator mounted on the platform.     

Comparison of Three‐Dimensional Korean Male Anthropometric Data with Modeling Data Generated by Digital Human Models

The purpose of this study was first to extract the anthropometric data of typical Korean male adults, based on the three‐dimensional anthropometric data measured through the Size Korea project. The data were then analyzed to identify the differences in the anthropometric characteristics between typical Koreans and 3D Korean mannequinmannequins generated by digital human models. Revision equations were then suggested to improve the inaccuracy of digital human models. Typical Korean adults subject to the 3D body scan data were selected by factor analysis with respect to the 5th, 50th, and 95th percentiles. Comparisons of anthropometric differences included the differences of the height and length variables in the vertical direction and the breadth, depth, and circumference variables in the horizontal direction. These comparisons demonstrated the differences in the anthropometric characteristics between typical Koreans and Korean mannequins based on differences in body shape and proportions between Korean and Western populations. Typical Koreans have shorter legs and longer torso than those of such mannequins generated from their own modeling algorithms, and the body shape of Koreans is more of an inverted triangular shape compared to the models. Although 3D digital human models are required to be modified to appropriately reflect the Asian body shape, modification of the modeling algoritms is not available to the public. The revision equations that convert the Korean modeling data of RAMSIS and Human in CATIA into typical Korean anthropometric data were instead suggested by regression analysis. It is expected that the proposed revision equations will help the designer evaluate design alternatives and improve the suitability of ergonomic evaluation for Korean customers. © 2012 Wiley Periodicals, Inc.     

双臂四自由度空间机器人捕捉未知目标的参数辨识

给出了双臂四自由度空间机器人捕捉未知目标的参数辨识方法．该方法基于线动量和角动量守恒定律,推出了机械臂负载未知目标的新的末端效应器的质量、质心和转动惯量的方程组. 在线测量当机械臂运动时的本体的线速度和角速度,以求得方程组中这些未知的惯性参数．数值试验显示了该方法的有效性．     

人体空中运动模拟在MATLAB和VC混编中的实现

该文深入研究了人体空中运动的11刚体人体多刚体模型,利用该模型可以计算出人体各环节的质量、质心位置以及沿过质心的三个正交轴的转动惯量,同时还讨论了该模型用于人体空中运动模拟时角动量及外部方位角的计算方法。在此模型基础上,开发了人体空中运动模拟系统,开发过程中使用MATCOM实现MATLAB和Visual C＋＋的混合编程。最后将真实人体及其跳水过程中通过摄像系统获取的一组实测数据代入系统进行计算,计算结果与真实值比较接近,在误差范围之内。     

Action recognition from only somatosensory information using spectral learning in a hidden Markov model

Human action classification is fundamental technology for robots that have to interpret a human’s intended actions and make appropriate responses, as they will have to do if they are to be integrated into our daily lives. Improved measurement of human motion, using an optical motion capture system or a depth sensor, allows robots to recognize human actions from superficial motion data, such as camera images containing human actions or positions of human bodies. But existing technology for motion recognition does not handle the contact force that always exists between the human and the environment that the human is acting upon. More specifically, humans perform feasible actions by controlling not only their posture but also the contact forces. Furthermore these contact forces require appropriate muscle tensions in the full body. These muscle tensions or activities are expected to be useful for robots observing human actions to estimate the human’s somatosensory states and consequently understand the intended action. This paper proposes a novel approach to classifying human actions using only the activities of all the muscles in the human body. Continuous spatio-temporal data of the activity of an individual muscle is encoded into a discrete hidden Markov model (HMM), and the set of HMMs for all the muscles forms a classifier for the specific action. Our classifiers were tested on muscle activities estimated from captured human motions, electromyography data, and reaction forces. The results demonstrate their superiority over commonly used HMM-based classifiers.     

个性化三维人体模型快速建模方法

采用模型重用的思想,通过输入21个人体测量学参数对标准人体模型进行编辑,实时获得相应体型的个性化三维人体模型．该方法使得编辑过程能够实时完成;生成的人体模型可以方便地驱动;精选的21个人体测量学参数覆盖了人体各处的细节,能够比较完整地描述人体的外形特征,满足对人体模型个性化的需求．     

Investigation of a method for the three-dimensional rigid body dynamics inverse problem

The three-dimensional rigid body dynamics inverse problem is cast as a discrete optimal control problem and solved using dynamic programming. The optimal control problem uses a forward dynamic model to provide estimates of unknown forces while matching noisy measurement histories. An L curve analysis is used to objectively select the amount of smoothing by trading off the magnitude of the estimated unknown forces with the fit to the noisy measurements. The forward dynamic model is derived using finite-element methodology and accounts for the inertia and mass properties of rigid bodies with the use of natural coordinates. The advantages of this forward model are that the large displacements’ nonlinearities can be routinely represented in the inverse problem and that it also allows the use of an exact energy conserving method to numerically integrate the equations of motion. A numerical example of a large displacement three body model is included to demonstrate the performance of the methodology.     

Parameter estimation for excavator arm using generalized Newton method

A robust, fast, and simple technique for the experimental identification of the link parameters (mass, inertia, and length) and friction coefficients of a full-scale excavator arm is presented. This new technique, based on the generalized Newton method (GNM), estimates unknown individual parameters of the excavator arm dynamic equations. The technique can be used when the number of equations is different from the number of estimated variables. Using experimental data from a full-scale field Combat Engineer Excavator (CEE), the values of link parameters and friction coefficients are successfully identified. The identified parameters are compared with known values, and shown to be in agreement. The method is compared with the least square method, and shows that the GNM is better in terms of prediction accuracy and robustness to noise. Further, the joint positions predicted by the analytical model using the identified parameters are validated against different experimental trajectories, showing very good agreement. The experimental data was obtained in collaboration with QinetiQ Ltd. (Hampshire, U.K.). The technique presented in this paper is general and can be applied to any manipulator.     

Dynamics analysis of a 3-RRP spherical parallel manipulator using the natural orthogonal complement

In the present research, application of the Natural Orthogonal Complement (NOC) for the dynamic analysis of a spherical parallel manipulator, referred to as SST, is presented. Both inverse and direct dynamics are considered. The NOC and the SST fully parallel robot are explained. To drive the NOC for the SST manipulator, constraints between joint variables are written using the transformation matrices obtained from three different branches of the robot. The Newton–Euler formulation is used to model the dynamics of each individual body, including moving platform and legs of the manipulator. D’Alembert’s principle is applied and Newton–Euler dynamical equations free from non-working generalized constraint forces are obtained. Finally two examples, one for direct and one for inverse dynamics are presented. The correctness and accuracy of the obtained solution are verified by comparing with the solution of the virtual work method as well as commercial multi-body dynamics software.     

Biomechanical analysis and assessment of lumbar stress during load lifting using a dynamic 19-segment human model

A dynamic biomechanical human model is presented which allows the quantification of mechanical parameters such as torque, compressive and shear forces, and pressure at the lumbar intervertebral discs. The human model comprises a total of 19 body segments. Various trunk flexions can be analysed due to the provision of 5 joints at the level of the 5 lumbar intervertebral discs. The influence of intraabdominal pressure on spinal load is considered. The inclusion of the influences of gravity and inertia permits the analysis of both static body postures and dynamic body movements. Since the model is 3-dimensional, the lumbar stress can be calculated during both symmetrical tasks in the median sagittal plane as well as during non-symmetrical ones. The influences on spinal stress of trunk inclination and the position of an external load relative to the body are quantified for various load weights up to 50 kg. The torque at the lumbo-sacral joint L5-S1 lies, dependent on posture and load lever-arm, within the range between 0 and 500 Nm; the compressive force on L5-S1 lies within the range between 0.4 and 10 kN, and the shear force at L5-S1 between 0.2 and 0.9 kN. The influences of lift velocity and jerky movement on lumbar stress are quantified. Simulated humpback and hollow-back postures are studied. The compressive forces at the 5 lumbar intervertebral discs are compared. The validity of the model is examined by comparing the model calculations with the intradiscal pressure measurements taken from the literature. Strength tests on lumbar intervertebral discs and vertebrae are collated from the literature in order to assess the lumbar stress during load lifting. The lumbar ultimate compression strength varies within a wide range. The mean value for a total of 307 lumbar segments amounts to 4.4 kN, the standard deviation to 1.9 kN. In conclusion, lumbar compressive force values during lifting fall within the same range as the strength values for the human lumbar spine.     

Exact dynamic stiffness matrix of non-symmetric thin-walled beams on elastic foundation using power series method

Exact dynamic element stiffness matrix for the flexural–torsional free vibration analysis of the shear deformable thin-walled beam with non-symmetric cross-section on two-types of elastic foundation is newly presented using power series method based on the technical computing program Mathematica. For this, the shear deformable beam on elastic foundation theory is developed by introducing Vlasov's assumption and applying Hellinger–Reissner principle. This beam includes the shear deformation effects due to the shear forces and the restrained warping torsion and due to the coupled effects between them, and rotary inertia effects and the flexural–torsional coupling effects due to the non-symmetric cross-sections. And then equations of motion and force–deformation relations are derived from the energy principle and explicit expressions for displacement parameters are derived based on power series expansions of displacement components and the exact dynamic element stiffness matrix is determined using force–deformation relationships. In order to verify the accuracy of this study, the numerical solutions are presented and compared with the analytical solutions and the finite element solutions using the isoparametric beam elements. Particularly the influences of the coupled shear deformation on the vibrational behavior of non-symmetric beam on elastic foundation are investigated.     

Child body shape measurement using depth cameras and a statistical body shape model

We present a new method for rapidly measuring child body shapes from noisy, incomplete data captured from low-cost depth cameras. This method fits the data using a statistical body shape model (SBSM) to find a complete avatar in the realistic body shape space. The method also predicts a set of standard anthropometric data for a specific subject without measuring dimensions directly from the fitted model. Since the SBSM was developed using principal component (PC) analysis, we formulate an optimisation problem to fit the model in which the degrees of freedom are defined in PC-score space. The mean unsigned distance between the fitted-model based on depth-camera data and the high-resolution laser scan data was 9.4 mm with a standard deviation (SD) of 5.1 mm. For the torso, the mean distance was 2.9 mm (SD 1.4 mm). The correlations between standard anthropometric dimensions predicted by the SBSM and manually measured dimensions exceeded 0.9.     

An approach to the identifiable parameters of a manipulator

This article deals with the minimal parameters of a manipulator in the least squares sense, so that the minimal parameters are equivalent to the identifiable parameters. The least squares concept is used to introduce terminology for the minimal linear combinations (MLCs) of the system parameters that define a set of linear combinations of the system parameters. The number of elements of the set is minimal, yet the set still completely determines the system. Furthermore, it is shown that the problem of finding a set of MLCs of a manipulator can be simplified to that of finding two individual sets of MLCs that determine the entries of the inertia matrix and the gravity load. Although the approach is applied to the inertia constants of composite bodies to obtain a set of MLCs identical to an earlier one, the result is newly interpreted in the least squares sense. The approach itself is a new method for finding the identifiable parameters of a manipulator, and it yields some new insight into the manipulator dynamics. The crucial feature is that a set of MLCs found by using the present approach is guaranteed to be identifiable. The earlier approaches always require an identification method to verify the results. An equivalence theorem is also presented that rigorously states the equivalence between the different sets of minimal parameters. © 1994 John Wiley & Sons, Inc.     

Anthropometrical data and coefficients of regression related to gender and race

As a result of migration and globalization, the requirement for anthropometrical data of distinct races and gender has augmented whilst the availability remained minimal. Therefore, several sets of estimation equations, which depend on gender, race, body height (BH), and body mass (BM), were established in this study to fulfill this necessity. The method consisted of: (a) an inexpensive device to scan the body surface, (b) the electronic reconstruction of the body surface and (c) a module to calculate segmental lengths, segmental masses, radii of gyration and moments of inertia, using the 16-segment model (Zatsiorsky, 1983) and density data of Dempster (Space requirements of the seated operator, WADC Technical Report, Wright-Patterson Air Force Base, Ohio, 1995, pp. 55-159), and (d) the establishment of regression equations. One hundred young Chinese and Germans, representing the Asian and Caucasian races, were randomly recruited to participate in this study. The results revealed contrasting trunk, limb lengths and relative skull volume (skull volume/body volume) between the two races as well as the independence of head mass from body height. The regression equations, which were successfully derived based on the above-unveiled differences, are capable of supplying a prompt way to obtain all anthropometrical parameters of different genders and race groups through individual BM and BH. Anthropometrical data are related to gender, race, BH and BM. In order to obtain the data, one can utilize various measurements, which might have enormous financial expenditure in addition to time-consumption or employ the convenient and economical short-cut-regression-to obtain such data. The results of this study reveal that the accuracy of such estimations is high. The errors of predictions lie under 0.7 Standard deviation, which will satisfy most of applications.