Human Walking Motion Research Articles

AN ULTRASONIC SENSOR FOR HUMAN PRESENCE DETECTION TO ASSIST RESCUE WORK IN LARGE BUILDINGS

Abstract. When the fire brigade arrives at a burning building, it is of vital importance that people who are still inside can quickly be found. Smart buildings should be able to expose this location data to the fire brigade working in a smart city. In this paper the feasibility is researched of using ultrasonic sound sensors for human presence detection in smoke-filled spaces. This type of sensor could assist the fire brigade when evacuating a large building by directing them to the places where their help is most needed. The advantage of ultrasonic sound over other sensors or cameras is that its signal is able to pierce through smoke, does not require badges or other wearable devices and introduces little privacy and security risks. In addition, ultrasonic sensors are very inexpensive making it possible to equip every room of a building with an ultrasonic presence detector. In this research both a preliminary ultrasound measuring device and signal processing algorithm have been designed. Testing results show that the walking movement of a person in an indoor area can be detected with the combination of the sensor and the algorithms. In addition, tests of the signal strength in smoke have shown that ultrasound is capable of “looking through” the smoke. The algorithm based on a particle filter allows for more information to be extracted from the relatively simple sensor signal by detecting human walking movement specifically and opens up the way for an ultrasound based indoor positioning system that can be used in emergency situations.

Learning motion rules from real data: Neural network for crowd simulation

Abstract This paper addresses the problem of efficiently simulating a believable virtual crowd. Our method is the first one that uses the Neural Network (NN) model to fit behaviors from real crowd data to a crowd simulation. Unlike several rule-based approaches that often result in ‘walking robots’, our model can learn motion rules derived from real data and later simulate human walking motions. Additionally, unlike the existing data-driven crowd simulation methods that have to perform search operations on the bound dataset simultaneously during the simulation, our model directly uses the NN model to generate the proper motion for each crowd member. The proposed method is being tested on various scenarios and compared with state-of-the-art state-action-based methods that are commonly employed in data-driven crowd simulation systems. The results demonstrate a significant increase in speed, as well as better simulation quality.

Energy Harvesting Combat Boot for Satellite Positioning.

Most portable electronic devices are power-limited by battery capacity, and recharging these batteries often interrupts the user’s experience with the device. The product presented in this paper provides an alternative to powering portables by converting regular human walking motion to electricity. The device harvests electric power using air bulbs, distributed in the sole of a shoe to drive a series of micro-turbines connected to small DC motors. The number and position of air bulbs is optimized to harvest the maximum airflow from each foot-strike. The system is designed to continuously drive the micro-turbines by utilizing both outflow and inflow from the air bulbs. A prototype combat boot was fitted on the right foot of a 75 kg test subject, and produced an average continuous power on the order of 10 s of mW over a 22 Ω load during walking at 3.0 mph. This combat boot provides enough electric power to a passive GPS tracker that periodically relays geographical coordinates to a smartphone via satellite without battery replacement.

Optimizing orientation of piezoelectric cantilever beam for harvesting energy from human walking

Harvesting energy from human body motion for powering small scale electronic devices is attracting research interest in recent years. Piezoelectric energy harvester (PEH) capable of harvesting energy from vibratory movement is a suitable candidate for this particular application. In this study, a cantilever beam with a piezoelectric patch attached at the end of the cantilever is evaluated for potential to harvest energy from human motion. Since the frequency of human walking motion is low, the frequency up conversion technique is adopted in this study to harvest the inertial energy. The effect of orientation of the cantilever beam with tip mass on the efficiency of the power generated is experimentally studied. A prototype is developed and attached onto the leg of a person walking on a treadmill at a constant speed. A theoretical lumped model is adopted to predict the voltage output using the experimentally measured acceleration as input data. Results show close agreement between the experiment and the model. Results also indicate that by varying the orientation of the PEH, the efficiency of the energy harvester can be significantly increased. Maximum power is found to be achieved when the PEH is orientated at 70° with reference to a coordinate system attached to the leg when walking on a treadmill.

Wearable triboelectric nanogenerators based on hybridized triboelectric modes for harvesting mechanical energy.

In this paper, we demonstrate a newly designed hybridized triboelectric nanogenerator (TENG) fabric incorporating multiple working modes, which can effectively harvest ambient mechanical energy for conversion into electric power by working in a hybridization of a contact–separation mode, a sliding mode and a freestanding triboelectric layer mode. The power generation of each mode of the TENG fabric was systematically investigated and compared along different directions, under different frequencies and at different locations. Owing to the advanced structural design, the as-fabricated TENG fabric could be switched between multiple working modes according to its real working situation. High output voltage and current of about 140 V and 0.6 μA, respectively, were obtained from a larger size of TENG fabric, which could be used to light up 120 LEDs in series. Compared to the previously reported TENGs, such a hybridized TENG fabric based on hybridized modes has much better adaptability for harvesting energy (such as human walking, running, and other human motion) in different directions. This work presents the promising potential of hybridized TENG fabric for power generation and self-powered wearable devices.

Design principles of a human mimetic humanoid: Humanoid platform to study human intelligence and internal body system.

Many systems and mechanisms in the human body are not fully understood, such as the principles of muscle control, the sensory nervous system that connects the brain and the body, learning in the brain, and the human walking motion. To address this knowledge deficit, we propose a human mimetic humanoid with an unprecedented degree of anatomical fidelity to the human musculoskeletal structure. The fundamental concept underlying our design is to consider the human mechanism, which contrasts with the conventional engineering approach used in the design of existing humanoids. We believe that the proposed human mimetic humanoid can be used to provide new opportunities in science, for instance, to quantitatively analyze the internal data of a human body in movement. We describe the principles and development of human mimetic humanoids, Kenshiro and Kengoro, and compare their anatomical fidelity with humans in terms of body proportions, skeletal structures, muscle arrangement, and joint performance. To demonstrate the potential of human mimetic humanoids, Kenshiro and Kengoro performed several typical human motions.

Visual Lifting Approach for Bipedal Walking with Slippage

[abstFig src='/00290003/05.jpg' width='300' text='Concept of visual lifting approach' ] Biped locomotion generated by control methods based on Zero-Moment Point (ZMP) has been achieved and its efficacy for stable walking, where ZMP-based walking does not include the falling state, has been verified extensively. The walking control that does not depend on ZMP – we call it dynamical walking – can be used in walking that utilizes kicks by toes, which looks natural but is vulnerable to turnover. Therefore, keeping the walking of dynamical motion stable is indispensable to the realization of human-like natural walking – the authors perceive the human walking, which includes toe off states, as natural walking. Our research group has developed a walking model, which includes slipping, impact, surface-contacting and line-contacting of foot. This model was derived from the Newton-Euler (NE) method. The “Visual Lifting Approach” (VLA) strategy inspired from human walking motion utilizing visual perception, was used in order to enhance robust walking and prevent the robot from falling, without utilizing ZMP. The VLA consists of walking gate generation visual lifting feedback and feedforward. In this study, simulation results confirmed that bipedal walking dynamics, which include a slipping state between foot and floor, converge to a stable walking limit cycle.

Dynamic simulation of contaminant inleakage produced by human walking into control room

Human walking-induced transport can be a significant mechanism during entry from a contaminated region into a protective enclosure, such as a control room. The passage through the door gives the outside air the opportunity to leak into the control room, endangering the staff inside. The objective of this study is to simulate contaminant transport induced by human walking motion in simplified situations – the person moving from the corridor into the anteroom, with various entrance times (from 2 to 8s). The CFD simulations were made by using the RANS solver with dynamic meshes techniques. The inleakage airflow through the doorway and the inleakage air volume can be both quantified with tracer gas measurements. The simulation results illustrated that the whole inleakage process can be divided into four stages: door draws in air; person entrains the air; door closing cuts short the wake; and door pushes the air in the final movement. It was found that the total inleakage volume is affected by the entrance time, and can be as much as 1.192m3 for an 8.0s entrance time. The data measured in our previous experimental study were employed to validate with the simulation result. The comparison result indicated an agreement when the entrance time was 3–8s, but as the entrance time increased, the simulation values were significantly higher than those measured experimentally. The simulation results can therefore be considered as a conservative estimate, which can guide the prevention of inleakage in future engineering applications.

Energy harvesting using flexible piezoelectric materials from human walking motion: Theoretical analysis

Human walking is a good energy source that can be harvested to support wearable devices. For one walking cycle, the muscles at each joint of human lower body consume tens of watts. The considerable amount of kinetic energy generated while walking can be turned to useful electric energy through energy transducers. In this article, we theoretically investigate energy harvesting from flexible piezoelectric materials attached to humans while walking. We focus on the hip, knee, and ankle motions of walking humans and analyze the frequency characteristic of the motions using Fourier series fitting. A model is utilized to predict the electrical responses from piezoelectric materials and the power harvested through load resistances. In particular, we estimate the harvested power from polyvinylidene fluoride and derive the contour maps with respect to the harvested power as a function of the load resistance and walking frequency. Moreover, we discuss the necessary mechanical power input required to deflect the energy harvester and the effects of the varied parameters.

Design and characterization of a low frequency 2-dimensional magnetic levitation kinetic energy harvester

This paper presents the design and characterization of the first completely orientation-independent magnetic levitation energy harvester for low power, low frequency, and low g applications. A fully symmetric design is presented able to operate in any orientation in a particular plane. A MATLAB/Simulink model has been developed to aid in optimizing harvester design. Resonant frequencies in the order of 2Hz are desirable for human walking motion energy harvesting applications. The presented harvester has been tuned to a resonant frequency of 8.2Hz, allowing it to take advantage of harmonics available from human walking motion. The harvester may be tuned to different frequencies with different magnet configurations and harvester dimensions with the aid of the MATLAB/Simulink model. The presented energy harvester has a measured power output of 41.0μW and 101μW at 0.1g and 0.2g accelerations, respectively.

Evaluation of a Backpack-Mounted 3D Mobile Scanning System

Recently, several backpack-mounted systems, also known as personal laser scanning systems, have been developed. They consist of laser scanners or cameras that are carried by a human operator to acquire measurements of the environment while walking. These systems were first designed to overcome the challenges of mapping indoor environments with doors and stairs. While the human operator inherently has the ability to open doors and to climb stairs, the flexible movements introduce irregularities of the trajectory to the system. To compete with other mapping systems, the accuracy of these systems has to be evaluated. In this paper, we present an extensive evaluation of our backpack mobile mapping system in indoor environments. It is shown that the system can deal with the normal human walking motion, but has problems with irregular jittering. Moreover, we demonstrate the applicability of the backpack in a suitable urban scenario.

3D analysis system for estimating intersegmental forces and moments exerted on human lower limbs during walking motion

The intersegmental forces and moments acting on the human lower limbs during walking are generally estimated by applying an inverse dynamics approach to the ground reaction force (GRF) acting on the feet. The GRF data is obtained either directly using force plates or by means of a curve-fitting technique based on experimental samples. However, force plates are inconvenient and expensive, while curve fitting is unreliable since significant variations may exist in the GRF among different individuals. Accordingly, the present study proposes a method for evaluating the intersegmental forces and moments acting on the lower limbs based solely on the posture information obtained from seven inertial measurement units (IMUs) placed on the lower limbs and trunk and a 3D analytical model of the human walking motion. The results obtained from the analytical model for the forces acting on the phalange and heel are compared with the experimental data obtained using load cells. It is found that a good agreement exists between the two sets of results. Thus, the basic validity of the proposed analysis system is confirmed.

Rice Channel Realization for BAN Over-The-Air Testing Using a Fading Emulator with an Arm-Swinging Dynamic Phantom

This paper presents a new methodology for realizing a Rice channel in BAN Over-The-Air (OTA) testing using a fading emulator with a dynamic phantom. For the proposed apparatus to be effective, the fading emulator must be provided with an appropriate K-factor that represents the actual propagation environment indoors. Further, an implementation of the Rice channel to the proposed fading emulator in a BAN situation is presented. Thereafter, a calibration method for the fading emulator to adjust the actual K-factor of the on-body Rice channel is advanced. This calibration method is validated by analyzing the variations in the instantaneous K-factor attributed to the arm-swinging motion. Finally, an experiment is conducted for a continuous human walking motion with the fading emulator using an arm-swinging dynamic phantom. The results show that the developed fading emulator allows BAN-OTA testing to replicate the actual Rice channel propagation environment with the consideration of the dynamic characteristics of human walking motion.

Validity of Kinect for Assessment of Joint Motion during Gait

One of the most common methods employed in gait analysis is the optical measurement method. While many analyzer systems are available commercially, the prices of those systems are rather prohibitive. In this work, an alternative method to obtain gait data using Microsoft KinectTM (Kinect) is investigated. Kinect, a 3D camera system created for gaming purposes, offers an ability which may be suitable for application in gait analysis. It has high mobility, needs no marker, is easy to use, and its price is relatively affordable. However, the performance of Kinect as a measurement tools in gait analysis must be first evaluated. In this work, Kinect is utilized to obtain joint movements of human walking motion to evaluate its suitability as an alternative motion analyzer in gait analyses. The data generated by Kinect are then processed to obtain gait parameters. The resulting parameters are compared to those obtained by 3D Motion Analyzer System that uses multi-camera previously developed. The results show promising prospect for Kinect application in gait analysis.

Survey on Video Analysis of Human Walking Motion

In computer vision related applications, video analysis of human walking motion is currently one of the most active research topics. The task of analyzing human walking can be divided into three distinct subtasks – human detection or segmentation, motion tracking and walking pose analysis. Typically, the analysis of the human walking starts with the extraction of motion information, detection of the presence of humans in the sequences of frames and then followed by analysis of events related to walking. This paper presents a survey of different methodologies used for human walking motion analysis, approaches used for human detection or segmentation, various tracking methods, approaches for pose estimation and pose analysis. The common data sets available for building robust, automatic and intelligent systems to understand “walking” motion are also included. Finally, uses of unsupervised techniques for analysing human walking are highlighted. Human walking motion is a subset of a broad topic of human motion analysis.

Development for generating electric power shoes having a vibrating sheet generator assembly

It is often seen an object move or vibrate repeatedly. Some phenomenons are useful, but another is unavailable motion. The unavailable motion makes a lot of energy dissipation. In order to utilize the energy unavailable motion makes, the research will use the energy to generate electric power for solving the deficient personal energy sources problems. In general, the generator coil sweeps the magnetic field line to generate the electric power these days. The revolving spindle will abrasion and the energy will loss. Therefore, the generating efficiency of electric power will decrease [1-4]. The research utilizes a structure of sheet generator to generate electric power. The present research relates to a method for manufacturing a sheet generator having a flat coil assembly, and more particularly to a method comprising the steps of placing a flat coil into an injecting mold; forming a locating section to secure the flat coil; and assembling the sheet generator. The relative motion between coil and magnet will generate electric power in accordance with the Fleming’s right-hand rule. In order to assess the efficiency of generating electric power, the research will design an experimental device to simulate the sheet generator. First, two plastic diaphragms be used to laminate the coil. Then, place the laminate diaphragm on the inverted U-shape structure of experimental device. Because the inverted U-shape structure and magnet move relatively, so the electric power will be produce by cutting magnetic field line. The server motor drives the cam to press the inverted U-shape structure. When the motor rotational speed is 120 r.p.m. (2Hz), then the voltage of generating electric power can obtain exceeds respectively 1.5V, 2.0V and 2.5V without assembling the bridge circuit at the coil of 1 layer, 2 layers and 3 layers, as shown in Table ​Table1.1. Actually, the voltages of generating electric power shoes exceed respectively 1V and 2V without assembling the bridge circuit under the human walking motion and running motion, as shown in Figure ​Figure1.1. The basic goal of the research has achieved. And the design parameters can easily provide the industry of electric power shoes. The industry of storage energy will be developed and established. Table 1 The table of relationship between number of coil layers and voltage Figure 1 Testers wore shoes for generating voltage measurements

Gait optimization of biped robots based on human motion analysis

This paper proposes a dynamically stable and optimal trajectory generation method for biped robots to walk up and down stairs, based on human motion analysis, since a human walks efficiently without high energy consumption, and the energy-efficient locomotion pattern results in a more natural walking pattern. Seven important elements of the human gait on stairs are identified in the analysis of the motion data captured from subjects. Those factors enable us to generate trajectories of biped robots similar to that of human beings walking up-and-down stairs. The dynamics of the robot and human are different in weight distribution, degree of freedom and so on. A real-coded genetic algorithm as an optimization tool is used to produce the optimized gait for the robot and to improve the energy autonomy and stability. Various computer simulations were performed based on a 12-DOF biped robot model with which many of the essential characteristics of the human walking motion on stairs can be captured. The proposed method exhibits its efficiency in quickly finding an optimal trajectory, which is due to not only the nature of genetic algorithms but also a small number of design variables employed. Thus, this makes it possible to generate various locomotion trajectories of biped robots simply by appropriately changing some of the boundary conditions.

BAN Radio Link Characterization Using an Arm-Swinging Dynamic Phantom Replicating Human Walking Motion

This paper presents a newly developed arm-swinging dynamic phantom that can simulate human walking and running motions. The arm-swinging phantom has unique features, in that swinging of the right and left arms and the direction and speed of swing can be controlled independently, leading to excellent capability for replicating the variety of natural walking and running styles seen in the average human. Using the phantom, we have attempted to develop a dynamic channel characterization for BAN systems, such as shadowing properties and path loss characteristics, when the geometrical relationships between the arms and the human body change continuously due to the movement of the arms for both off-body and on-body situations. Assessments of communication quality, such as the signal bit error rate, were also conducted to gain useful knowledge of the way and the degree to which arm-swinging might impact the performance of body-attached BAN devices. Analytical results are also shown for the case where the combined outcome of shadowing and multipath fading emerge simultaneously when a human walks in a multiple radio wave propagation environment while swinging both arms.

Energy harvesting from human motion and bridge vibrations: An evaluation of current nonlinear energy harvesting solutions

A large quantity of recent research into the harvesting of electrical energy from ambient vibration sources has been focused on the improvement of device performance via the deliberate introduction of dynamic nonlinearities. In addition to this, the realisation that most of these kinetic energy sources are stochastic in nature has led to many studies focusing on the response of energy harvesters to random vibrations (often Gaussian white noise). This differs from early studies in which it was assumed that ambient vibration sources were sinusoidal. The aim of the present study is to take current nonlinear energy harvesting solutions and to numerically analyse their effectiveness when two real ambient vibration sources are used: human walking motion and the oscillation of the midspan of a suspension bridge. This study shows that the potential improvements that can be realised through the introduction of nonlinearities into energy harvesters are sensitive to the type of ambient excitation to which they are subjected. Additionally, the need for more research into the development of low-frequency energy harvesters is emphasised.

Shadowing-Fading BER Characterization of a BAN Diversity Antenna Based on Statistical Measurements of the Human Walking Motion

Shadowing-Fading BER Characterization of a BAN Diversity Antenna Based on Statistical Measurements of the Human Walking Motion