Motion Capture Suit Research Articles

Classification of Horse Gaits Using FCM-Based Neuro-Fuzzy Classifier from the Transformed Data Information of Inertial Sensor.

In this study, we classify four horse gaits (walk, sitting trot, rising trot, canter) of three breeds of horse (Jeju, Warmblood, and Thoroughbred) using a neuro-fuzzy classifier (NFC) of the Takagi-Sugeno-Kang (TSK) type from data information transformed by a wavelet packet (WP). The design of the NFC is accomplished by using a fuzzy c-means (FCM) clustering algorithm that can solve the problem of dimensionality increase due to the flexible scatter partitioning. For this purpose, we use the rider’s hip motion from the sensor information collected by inertial sensors as feature data for the classification of a horse’s gaits. Furthermore, we develop a coaching system under both real horse riding and simulator environments and propose a method for analyzing the rider’s motion. Using the results of the analysis, the rider can be coached in the correct motion corresponding to the classified gait. To construct a motion database, the data collected from 16 inertial sensors attached to a motion capture suit worn by one of the country’s top-level horse riding experts were used. Experiments using the original motion data and the transformed motion data were conducted to evaluate the classification performance using various classifiers. The experimental results revealed that the presented FCM-NFC showed a better accuracy performance (97.5%) than a neural network classifier (NNC), naive Bayesian classifier (NBC), and radial basis function network classifier (RBFNC) for the transformed motion data.

컴퓨터 디자인 기반 모노스키 버킷 사용에 따른 장애인 알파인 스키 선수의 운동학적 특성 변화 연구: 사례 연구

ssistive Technology Service Center of Seoul, Republic of KoreaReceived 15 November 2014 Received in revised form 3 December 2014 Accepted 10 December 2014 ABSTRACT The purpose of the study was to investigate the effect of CAD (Computer Aided Design) based alpine mono-ski bucketdesign on disabled ski athletes’ kinematic characteristics. Two national team ski athletes with LW11 disabilities (Loco-motion Winter Classification) category for sit ski participated in both pre and post experiment. Both of the subjects per-formed 3 trials of carved turn on a ski slope under two conditions. Where, subject “A” performed pre experiment withpersonal bucket and post experiment with the newly developed CAD based bucket whereas, Subject “B” as control subjectperformed both pre and post experiment with his personal bucket. For the experiment, 24 Infrared cameras were positionedon the ski slope which covered the path of the ski turn. Also, motion capture suit with reflective markers were worn byboth subjects. In the result, decrement in medial/lateral displacement of COM, anterior/posterior displacement of COM,flexion/extension angle of trunk as well as velocity losing rate of COM was observed in subject “A” when using the newlydeveloped CAD based bucket. In contrast, no larger effect on performance was observed when using personal buckets. Inconclusion, the findings obtained from the study indicated effectiveness of newly developed CAD based bucket by reducingexcessive movement of hip and trunk which is an important factor to perform an effective turn. Keywords :

Effect of arm swing strategy on local dynamic stability of human gait

IntroductionFalling causes long term disability and can even lead to death. Most falls occur during gait. Therefore improving gait stability might be beneficial for people at risk of falling. Recently arm swing has been shown to influence gait stability. However at present it remains unknown which mode of arm swing creates the most stable gait. AimTo examine how different modes of arm swing affect gait stability. MethodTen healthy young male subjects volunteered for this study. All subjects walked with four different arm swing instructions at seven different gait speeds. The Xsens motion capture suit was used to capture gait kinematics. Basic gait parameters, variability and stability measures were calculated. ResultsWe found an increased stability in the medio-lateral direction with excessive arm swing in comparison to normal arm swing at all gait speeds. Moreover, excessive arm swing increased stability in the anterior–posterior and vertical direction at low gait speeds. Ipsilateral and inphase arm swing did not differ compared to a normal arm swing. DiscussionExcessive arm swing is a promising gait manipulation to improve local dynamic stability. For excessive arm swing in the ML direction there appears to be converging evidence. The effect of excessive arm swing on more clinically relevant groups like the more fall prone elderly or stroke survivors is worth further investigating. ConclusionExcessive arm swing significantly increases local dynamic stability of human gait.

체감형 스키 시뮬레이터 개발을 위한 플루크보겐 동작의 운동역학적 비교

The purpose of this study was to compare pflugbogen's biomechanical characteristics between on the ski simulator and snowed ski slope to develop interactive ski simulator. Nine ski instructors(sex: male, age: <TEX>$29.6{\pm}5.4yrs$</TEX>, height: <TEX>$176.0{\pm}5.6cm$</TEX>, body mass: <TEX>$76.0{\pm}14.0kg$</TEX>) belong to Korean Ski Instructors Association participated in this research. 24 Infrared cameras for snowed ski slope experiment and 13 infrared camera for ski simulator experiment were installed near by path of pflugbogen. The participants did pflugbogen on the snowed ski slope and the ski simulator both. During the experiment, the participants weared motion capture suit with infrared reflective makers on it, and plantar pressure sensors in ski boots, so that ski motion and plantar pressure data were collected together. Displacement of COG(center of gravity) movements, trunk flexion/extension angle, adduction/abduction angle, and plantar pressure data were significantly different between on the simulator and ski slope. However, percentage of time of COG movement in the phases during medial/lateral and anterior/posterior movement were not significantly different. Findings indicate that the difference between two groups occurred because the ski simulator's drive mechanism is different from ski motion on the slope. In order to develop the ski simulator more interactively for pflugbogen, the ski simulator's drive mechanism need to be reflected 3D motion data of pflugbogen on the slope that were purposed in this research.

A preliminary investigation of the use of inertial sensing technology for the measurement of hip rotation asymmetry in horse riders

This study investigated the use of inertial sensing technology as an indicator of asymmetry in horse riders, evidenced by discrepancies in the angle of external rotation of the hip joint. Twelve horse and rider combinations were assessed with the rider wearing the XsensTM MVN inertial motion capture suit. Asymmetry (left vs right) was revealed in mean hip external rotation of all riders, with values ranging from 1° to 27°, and 83% showed greater external rotation of the right hip. This study represents novel use of inertial sensing equipment in its application to the measurement of rider motion patterns. The technique is non-invasive, is capable of recording rider hip rotation asymmetry whilst performing a range of movements unhindered and was found to be efficient and practical, with potential to further advance the analysis of horse and rider interactions.

The Experimental Study of the Influence of the Foot Articulated Structure on the Biped Robot Walking

Abstract: Purpose：By investigating the variation of the human walking gait kinematics with respect to the foot deformation constraint, prove that bionic design of feet are the necessity for biped robots to imitate human walking better in terms of flexibility, stability and efficiency. The results will be significant for future research and development of biped robots. Methods: A human being was assumed as a perfect biped robot which had ideal motion drive and control. The walking gait parameters of two healthy men with foot deformation unconstrained and constrained were tested respectively by the inertia motion capture suit, and then they were processed by programming and analyzed by comparison. Results: The data analysis showed that when subjects walked with foot deformation constrained, their angular displacements of lower limb joints generally increased, the curves of angular velocity and accelerations fluctuated in certain walking phases, the walking pace and stride length decreased obviously, the single support phase shortened while the double support phase lengthened. At the same time, subjects felt subjectively that their body motion was less flexible, the walking posture was difficult to control, and the walking stability was more strenuous to keep. Conclusion: Combining the logical analogies with the detailed experimentation results, it is inferred that biped robots with rigid feet will have to suffer awkward and unstable walking gait, heavier and strenuous steps, and lower energy efficiency while walking. The paper concludes the necessity of bionic design of the robot feet for improving the walking quality of the biped robots. The conclusion and the experiment data will be of significant value for future work of robot design and evaluation.

Biomechanical differences between experienced and inexperienced wheelchair users during sport

During functional wheelchair movement there are several types of stroke pattern that a manual wheelchair user (MWCU) can utilize in order to propel. To examine the biomechanical differences between disabled (WCU) and able-bodied (NWCU) children whilst taking part in functional activities at the Cheetahs Wheelchair Sports Club. A multiple measures cohort study. Eleven participants were divided into two groups; WCU (n = 7) and NWCU (n = 4). All subjects were asked to perform three functional tasks; 30-second agility test, 1-minute distance test and a 10-metre sprint test. Upper body kinematics were recoded using a XSens MVN BIOMECH motion capture suit. NWCU outperformed the WCU in all of the tasks, however, no significant differences between the group's results were found. Nevertheless, significant differences were found in the maximum shoulder flexion angle for both right and left with NWCU utilizing more flexion and near significant differences in the NWCU overall shoulder range for right and left. In order to increase function in young MWCU then more specific-based sessions should be implemented targeting the exploitation of large shoulder ranges during propulsion, consequently resulting in more efficient movement.

Activity-Based Estimation of Human Trajectories

We present a novel approach to incrementally determine the trajectory of a person in 3-D based on its motions and activities in real time. In our algorithm, we estimate the motions and activities of the user given the data that are obtained from a motion capture suit equipped with several inertial measurement units. These activities include walking up and down staircases, as well as opening and closing doors. We interpret the first two types of activities as motion constraints and door-handling events as landmark detections in a graph-based simultaneous localization and mapping (SLAM) framework. Since we cannot distinguish between individual doors, we employ a multihypothesis tracking approach on top of the SLAM procedure to deal with the high data-association uncertainty. As a result, we are able to accurately and robustly recover the trajectory of the person. Additionally, we present an algorithm to build approximate geometrical and topological maps based on the estimated trajectory and detected activities. We evaluate our approach in practical experiments that are carried out with different subjects and in various environments.

3D measurements of alpine skiing with an inertial sensor motion capture suit and GNSS RTK system

To date, camcorders have been the device of choice for 3D kinematic measurement in human locomotion, in spite of their limitations. This study examines a novel system involving a GNSS RTK that returns a reference trajectory through the use of a suit, imbedded with inertial sensors, to reveal subject segment motion. The aims were: (1) to validate the system's precision and (2) to measure an entire alpine ski race and retrieve the results shortly after measuring. For that purpose, four separate experiments were performed: (1) forced pendulum, (2) walking, (3) gate positions, and (4) skiing experiments. Segment movement validity was found to be dependent on the frequency of motion, with high accuracy (0.8°, s = 0.6°) for 10 s, which equals ∼10 slalom turns, while accuracy decreased slightly (2.1°, 3.3°, and 4.2° for 0.5, 1, and 2 Hz oscillations, respectively) during 35 s of data collection. The motion capture suit's orientation inaccuracy was mostly due to geomagnetic secular variation. The system exhibited high validity regarding the reference trajectory (0.008 m, s = 0.0044) throughout an entire ski race. The system is capable of measuring an entire ski course with less manpower and therefore lower cost compared with camcorder-based techniques.