Motion Measurement System Research Articles

Gait motion simulator for kinematic tests of above knee prostheses

In this study, a basic gait motion simulator mechanism combining control units and electromechanic hardware has been proposed and implemented for the test stages of knee prostheses. The main goal to develop such simulator equipment is to regenerate predefined and controllable periodic movement, specifically hip vertical displacement and thigh angle motion applied to above-knee prosthesis so that test studies will be less dependent to human trials in any development phase. Gait motion simulator performance tests were conducted with both an image-based motion measurement system and a direct-type motion measurement system. In the hip simulator performance evaluation phase, accelerometer and video signals were collected simultaneously from the experimental system for kinematic analysis. The overall system consists of a hip simulator, a microcontroller-controlled prosthetic knee and a solid ankle cushion heel foot on a treadmill. Experimental results were evaluated for assessing the degree of approximation of the natural periodic hip movement by designed electromechanical simulator. The analysis showed that the test platform presented in this study is a useful yet low budget alternative to more expensive general-purpose electromechanic test devices for development purposes.

Consistent accuracy in whole-body joint kinetics during gait using wearable inertial motion sensors and in-shoe pressure sensors

To analyze human motion such as daily activities or sports outside of the laboratory, wearable motion analysis systems have been recently developed. In this study, the joint forces and moments in whole-body joints during gait were evaluated using a wearable motion analysis system consisting of an inertial motion measurement system and an in-shoe pressure sensor system. The magnitudes of the joint forces and the moments in nine joints (cervical, thoracic, lumbar, right shoulder, right elbow, right wrist, right hip, right knee, and right ankle) during gait were calculated using the wearable system and the conventional system, respectively, based on a standard inverse dynamics analysis. The averaged magnitudes of the joint forces and moments of five subjects were compared between the wearable and conventional systems in terms of the Pearson's correlation coefficient and the normalized root mean squared error to the maximum value from the conventional system. The results indicated that both the joint forces and joint moments in human whole body joints using wearable inertial motion sensors and in-shoe pressure sensors were feasible for normal motions with a low speed such as walking, although the lower extremity joints showed the strongest correlation and overall the joint moments were associated with relatively smaller correlation coefficients and larger normalized root mean squared errors in comparison with the joint forces. The portability and mobility of this wearable system can provide wide applicability in both clinical and sports motion analyses.

Using a virtual environment to study child pedestrian behaviours: a comparison of parents’ expectations and children's street crossing behaviour

ObjectiveThe aim of this study was to compare parents’ expectations for their children crossing streets with children's actual crossing behaviours and determine how accurately parents judge their own children's pedestrian...

Application of a novel spinal posture and motion measurement system in active and static sitting

The quantification of work-related musculoskeletal risk factors is of great importance; however, only a few tools allow objective, unrestricted measurements of spinal posture and motion in workplaces. This study was performed to evaluate the applicability of the Epionics system in a sedentary workplace. The system is mobile and wireless and assesses lumbar lordosis, pelvic orientation and spinal motion, without restricting subjects in their movements. In total, 10 males were monitored while sitting for 2 h on static and dynamic office chairs and on an exercise ball, to evaluate the effect of dynamic sitting. The volunteers were able to perform their work unhampered. No differences among the tested furniture could be detected with respect to either the lordosis or the number of spinal movements after habituation to the furniture; however, differences in pelvic orientation were statistically significant. The results of the present study indicate that Epionics may be useful for the quantitative assessment of work-related risk factors.

Using a Virtual Environment to Study Pedestrian Behaviors: How Does Time Pressure Affect Children's and Adults' Street Crossing Behaviors?

The aim of this study was to examine how crossing under time pressure influences the pedestrian behaviors of children and adults. Using a highly immersive virtual reality system interfaced with a 3D movement measurement system, various indices of children's and adults' crossing behaviors were measured under time-pressure and no time-pressure conditions. Pedestrians engaged in riskier crossing behaviors on time-pressure trials as indicated by appraising traffic for a shorter period before initiating their crossing, selecting shorter more hazardous temporal gaps to cross into, and having the car come closer to them (less time to spare). There were no age or sex differences in how time pressure affected crossing behaviors. The current findings indicate that, at all ages, pedestrians experience greater exposure to traffic dangers when they cross under time pressure.

Comparison of Artificial Immune System and Particle Swarm Optimization Techniques for Error Optimization of Machine Vision Based Tool Movements

In conventional tool positioning technique, sensors embedded in the motion stages provide the accurate tool position information. In this paper, a machine vision based system and image processing technique for motion measurement of lathe tool from two-dimensional sequential images captured using charge coupled device camera having a resolution of 250 microns has been described. An algorithm was developed to calculate the observed distance travelled by the tool from the captured images. As expected, error was observed in the value of the distance traversed by the tool calculated from these images. Optimization of errors due to machine vision system, calibration, environmental factors, etc. in lathe tool movement was carried out using two soft computing techniques, namely, artificial immune system (AIS) and particle swarm optimization (PSO). The results show better capability of AIS over PSO.

Quantitative analysis of facial palsy using a three-dimensional facial motion measurement system.

The prognosis for facial nerve palsy (FNP) depends on its severity. Currently, many clinicians use the Yanagihara, House-Brackmann, and/or Sunnybrook grading systems to assess FNP. Although these assessments are performed by experts, inter- and intra-observer disagreements have been demonstrated. The quantitative and objective analyses of the degree of FNP would be preferred to monitor functional changes and to plan and evaluate therapeutic interventions in patients with FNP. Numerous two-dimensional (2-D) assessments have been proposed, however, the limitations of 2-D assessment have been reported. The purpose of this study was to introduce a three-dimensional (3-D) image generation system for the analysis of facial nerve palsy (FNP) and to show the correlation between the severity of FNP assessed by this method and two conventional systems. Five independent facial motions, resting, eyebrow raise, gentle eye closure, full smile with lips open and whistling were recorded with our system and the images were then analyzed using our software. The regional and gross facial symmetries were analyzed. The predicted scores were calculated and compared to the Yanagihara and H-B grading scores. We analyzed 15 normal volunteers and 42 patients with FNP. The results showed that 3-D analysis could measure mouth movement in the anteroposterior direction, whereas two-dimensional analysis could not. The system results showed good correlation with the clinical results from the Yanagihara (r(2)=0.86) and House-Brackmann (r(2)=0.81) grading scales. This objective method can produce consistent results that align with two conventional systems. Therefore, this method is ideally suited for use in a routine clinical setting.

A 3-D Quasi-Zero-Stiffness-Based Sensor System for Absolute Motion Measurement and Application in Active Vibration Control

A novel 3-D quasi-zero-stiffness (3DQZS) system is proposed to construct a 3-D sensor system for absolute motion measurement in vibration systems. The 3DQZS system is achieved by employing a predeformed scissor-like structure. With mathe- matical modeling and the harmonic balance method, the nonlinear dynamic response of the 3-D sensor system is deeply analyzed. It is shown that this novel 3DQZS-based sensor system is very effective and reliable in 3-D absolute motion measurement in vi- bration systems. A case study in active vibration control using the proposed 3-D sensor indicates that much better vibration control performance can be readily achieved compared with conventional methods using a similar linear feedback controller. This novel sen- sor system should provide an alternative or much better solution to many vibration control problems in various engineering practices. Index Terms—Active vibration control, nonlinear system, quasi- zero stiffness (QZS), scissor-like structure (SLS), vibration sensor.

Innovations in using virtual reality to study how children cross streets in traffic: evidence for evasive action skills

PurposeChildren in middle childhood are at an increased risk for injury in pedestrian environments. This study examined whether they are capable of showing evasive action (ie, adjusting crossing speed) to...

J2410106 3次元動作計測システムおよび3軸力センサによる引掻き動作の基礎的解析

Monitoring of scratching motion, accompany with itchiness, is important for the medical treatment of skin diseases associated with itchiness. In previous study, the sensor system for measuring human scratching by scratch sound is developed and the relationship between the scratch sounds and the mechanical characteristics of human scratch motion was investigated. However, evaluation of human scratching motion against their own skin is not enough, because it is difficult to measure the contact force against human skin during scratching human skin. Therefore, in this paper, in order to measure the contact force, such as pressing force and shearing force of human scratching motion against their own skin, a contact force estimation method using three dimensional motion measurement system is proposed. In experiment, motions of scratching weakly and strongly artificial skin placed on 3-axis force sensor were measured. And finger tip trajectories and deformation of artificial skin were analyzed and compared with contact force. From the result, it is confirmed that the proposed estimation method is available to estimate the contact force during scratching.

3-D Facial Motion Measurement System for Quantification of Facial Palsy

3-D Facial Motion Measurement System for Quantification of Facial Palsy

Measurement Accuracy of a Compact Eye Movement Measurement System for Vertigo Diagnosis Support

Measurement Accuracy of a Compact Eye Movement Measurement System for Vertigo Diagnosis Support

Malaligned dynamic anterior cervical plate: a biomechanical analysis of effectiveness.

Biomechanical evaluation. To evaluate the kinematic and load-sharing differences of dynamic anterior cervical plates when placed in-line at 0° and off-axis at 20°. The use of dynamic anterior cervical plating systems has recently gained popularity due to the theoretical benefit of improved load sharing with graft subsidence. Occasionally, due to anatomical restraints, the anterior cervical plate may be placed off-axis in the coronal plane. This may potentially decrease the dynamization capability of the plate, leading to less load sharing and potentially decreased fusion rates. The purpose of this study was to comprehensively evaluate the kinematic and load-sharing differences of a dynamic plate placed in-line versus off-axis in the coronal plane. Thirteen fresh-frozen human cadaveric cervical spines (C2-T1) were used. Nondestructive range-of-motion testing was performed with a pneumatically controlled spine simulator in flexion/extension, lateral bending, and axial rotation using the OptoTrak motion measurement system. A C5 corpectomy was performed, and a custom interbody spacer with an integrated load cell collected load-sharing data under axial compression at varying loads. A dynamic anterior cervical plate was placed in-line at 0° and then off-axis at 20°. Testing conditions ensued using a full-length spacer, followed by simulated subsidence by removing 10% of the height of the original spacer. There were no kinematic differences noted in the in-line model versus the off-axis model. After simulated subsidence, the small decreases in stiffness and increases in motion were similar whether the plate was placed in-line or off-axis in all 3 planes of motion. There were also no significant differences in the load-sharing characteristics of the in-line plate versus the off-axis plate in either the full-length model or the subsided interbody model. This study suggests that off-axis dynamic plate positioning does not significantly impact construct kinematics or graft load sharing. As such, we do not recommend removal or repositioning of an off-axis placed dynamic plate because the kinematic and load-sharing biomechanical properties are similar. N/A.

Design and Modeling of an Active Five-Axis Compliant Micromanipulator

This paper presents the design and modeling of an active five-axis compliant micromanipulator whose tip orientation can be independently controlled by large angles about two axes and the tip-position can be controlled in three dimensions. These features enable precise control of the contact point of the tip and the tip–sample interaction forces with three-dimensional nanoscale objects, including those features that are conventionally inaccessible. Control of the tip-motion is realized by means of electromagnetic actuation combined with a novel kinematic and structural design of the micromanipulator, which, in addition, also ensures compatibility with existing high-resolution motion-measurement systems. The design and analysis of the manipulator structure and those of the actuation system are first presented. Quasi-static and dynamic lumped-parameter (LP) models are then derived for the five-axis compliant micromanipulator. Finite element (FE) analysis is employed to validate these models, which are subsequently used to study the effects of tip orientation on the mechanical characteristics of the five-axis micromanipulator. Finally, a prototype of the designed five-axis manipulator is fabricated by means of focused ion-beam milling (FIB).

An Efficient Vision-Based Three-Dimensional Motion Measurement System for Civil Infra-Structures

This study presents an effective three-dimension (3D) motion measurement system for civil infra-structures. The proposed system consists of hardware (three camcorders, one commercial PC, and one frame grabber) and software. The efficient software and measurement scheme, and automatic optimal threshold selection algorithm are successfully developed to obtain the dynamic motion with six degrees of freedom in real-time. The images of target panels attached to a structure are captured by three camcorders and then streamed into the PC via the frame grabber. Then six degrees of freedom of the dynamic motion are calculated using image processing techniques with pre-measured calibration parameters. Several laboratory tests including static and dynamic tests were conducted to verify the effectiveness of the proposed system with an error of less than 4%.

Real-time motion control and data acquisition system for scanning X-ray microscopy using programmable hardware

We developed a real-time motion control and measurement system for a scanning transmission X-ray microscope. The system was designed with an FPGA (field-programmable gate array), which is a programmable, reconfigurable circuit for real-time feature modification. This system enabled specimen stage control driven by a piezoelectric element and precise stage position measurement with a laser interferometer. Programmable hardware processing with FPGA realized high-speed control and measurement that cannot be handled by software processing. This system enables very high-speed control and measurement such as "on the fly" measurement.

KCS선형의 천수영역에서의 자세 변화에 대한 실험적 연구

When a ship sails in shallow water, it is well known that an additional sinkage and trim of the ship(squat) is caused by change of hydrodynamic force between the seabed and the bottom of a ship. In this paper, to examine this phenomenon by model tests, the squat of KCS model ship at a low speed is measured by the vision based ship motion measurement system during HPMM tests. Various combinations of a ship speed, a rudder angle and a drift angle were tested at three depth conditions(H/T = 1.2, 1.5 & 2.0). As a result, increase of the ship's speed and ship's drift angle caused an increase in ship squat, but the ship's rudder angle did not. The rate of increase in ship squat was the most at H/T = 1.2 condition. Lastly these experimental results are compared to the results by three empirical formulas and two CFD methods. The tendency of ship squat measured by experiment is similar to those of empirical formulas.

3P2-X04 高齢者の転倒予防を目的とした歩行計測および評価手法の検討(看護とメカトロニクス)

A quantitative and effective evaluation of a human lower limb movement is very important in clinical gait analysis. Therefore, we propose "Leg motion measurement and gait evaluation system" which can be applied for clinical gait analysis. In this paper, we will improve the performance of the proposed measurement system and apply to the gait analysis for elderly people.

Hardware Selection for Realization of Ultra-portable Wireless Human Motion Measurement System

Gait analysis is a very important procedure in assessing and improving many quality of life indicators. It is widely used in sports, rehabilitation and health diagnostics. Gait analysis is the study of lower limb movement patterns and involves the identification of gait events and the measurements of kinetics and kinematics parameters. This paper focus on the study and analysis of various design of gait analysis hardware. It also involves the practicality and the suitability of the hardware design to improve the accuracy of the gait analysis. The concept of the hardware is based on the attachment unit which consist of sensor, microcontroller, power supply and Xbee transceiver to the shoe. The selection of sensors and several additional component will also discussed. The result highlights the design and realization of the hardware components for the development of shoe integrated instrumentation for human motion measurement system.

3P2-F02 膝関節ロボットにおける膝関節の屈伸運動の模擬精度向上(リハビリテーションロボティクス・メカトロニクス)

Students becoming a physical therapist (PT) or an occupational therapist (OT) cannot have enough rehabilitation experience with actual patients before the clinical training. For this reason, we have developed Knee Joint Robot simulating patients' troubles for students to experience rehabilitation for patient's troubles virtually. Furthermore, we have developed a training program using the robot for the students to learn skilled manual training/testing techniques for patients' troubles. This paper presents a control method of KneeRobo in order to improve the simulation accuracy of involuntary movements during knee flexion and extension. The simulation accuracy of KneeRobo was verified with three dimensional motion measurement system in the experiment compared to the previous method.