scholarly journals Landing Control of Foot with Springs for Walking Robots on Rough Terrain

10.5772/7238 ◽  
2009 ◽  
Vol 6 (3) ◽  
pp. 25 ◽  
Author(s):  
Moyuru Yamada ◽  
Shigenori Sano ◽  
Naoki Uchiyama
Keyword(s):  
Controller Design ◽  
Impact Force ◽  
Reaction Force ◽  
Walking Robots ◽  
Flat Surfaces ◽  
Uneven Terrain ◽  
Biped Walking Robot ◽  
Foot Position ◽  
The Impact ◽  
Landing Control

Landing control is one of the important issues for biped walking robot, because robots are expected to walk on not only known flat surfaces but also unknown and uneven terrain for working at various fields. This paper presents a new controller design for a robotic foot to land on unknown terrain. The robotic foot considered in this study equips springs to reduce the impact force at the foot landing. There are two objectives in the landing control; achieving the desired ground reaction force and positioning the foot on unknown terrain. To achieve these two objectives simultaneously by adjusting the foot position, we propose a PI force controller with a desired foot position, which guarantees the robust stability of control system with respect to terrain variance, and exact positioning of the foot to unknown terrain. Simulation results using the Open Dynamics Engine demonstrate the effectiveness of the proposed controller.

Swizzle Movement for Biped Walking Robot Having Passive Wheels

2008 ◽  
Vol 20 (3) ◽  
pp. 413-419 ◽  
Author(s):  
Kenji Hashimoto ◽  
◽  
Yusuke Sugahara ◽  
Hun-ok Lim ◽  
Atsuo Takanishi ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Reaction Force ◽  
Internal Force ◽  
Walking Robots ◽  
Rough Terrain ◽  
Walking Robot ◽  
Biped Walking ◽  
Reference Position ◽  
Flat Surfaces ◽  
Biped Walking Robot

Biped walking is easily adapted to rough terrain such as stairs and stony paths, but speed and energy efficiency on flat surfaces is less effective than wheeled locomotion. We propose new control for swizzling by biped walking robots using inline skates. Swizzling uses friction force generated by regular passive wheel movement. Our proposal is based on the reaction force on the foot, and new reference position is changed based on reaction force not to be large internal force. Through hardware experiments, the effectiveness of the proposed method was confirmed.

A 6-Week Transition to Maximal Running Shoes Does Not Change Running Biomechanics

2019 ◽  
Vol 47 (4) ◽  
pp. 968-973 ◽  
Author(s):  
J.J. Hannigan ◽  
Christine D. Pollard
Keyword(s):  
Ground Reaction Force ◽  
Loading Rate ◽  
Impact Force ◽  
Reaction Force ◽  
Vertical Ground Reaction Force ◽  
Risk Of Injury ◽  
Impact Peak ◽  
Running Shoes ◽  
Vertical Ground ◽  
The Impact

Background: A recent study suggested that maximal running shoes may increase the impact force and loading rate of the vertical ground-reaction force during running. It is currently unknown whether runners will adapt to decrease the impact force and loading rate over time. Purpose: To compare the vertical ground-reaction force and ankle kinematics between maximal and traditional shoes before and after a 6-week acclimation period to the maximal shoe. Study Design: Controlled laboratory study. Methods: Participants ran in a traditional running shoe and a maximal running shoe during 2 testing sessions 6 weeks apart. During each session, 3-dimensional kinematics and kinetics were collected during overground running. Variables of interest included the loading rate, impact peak, and active peak of the vertical ground-reaction force, as well as eversion and dorsiflexion kinematics. Two-way repeated measures analyses of variance compared data within participants. Results: No significant differences were observed in any biomechanical variable between time points. The loading rate and impact peak were higher in the maximal shoe. Runners were still everted at toe-off and landed with less dorsiflexion, on average, in the maximal shoe. Conclusion: Greater loading rates and impact forces were previously found in maximal running shoes, which may indicate an increased risk of injury. The eversion mechanics observed in the maximal shoes may also increase the risk of injury. A 6-week transition to maximal shoes did not significantly change any of these measures. Clinical Relevance: Maximal running shoes are becoming very popular and may be considered a treatment option for some injuries. The biomechanical results of this study do not support the use of maximal running shoes. However, the effect of these shoes on pain and injury rates is unknown.

scholarly journals Numerical Investigation on Dynamic Response of RC T-Beams Strengthened with CFRP under Impact Loading

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 890
Author(s):  
Huiling Zhao ◽  
Xiangqing Kong ◽  
Ying Fu ◽  
Yihan Gu ◽  
Xuezhi Wang
Keyword(s):  
Numerical Simulation ◽  
Impact Force ◽  
Reaction Force ◽  
Impact Resistance ◽  
Structural Response ◽  
Element Model ◽  
Strengthening Effect ◽  
Strengthened Beam ◽  
Simulation Results ◽  
The Impact

To precisely evaluate the retrofitting effectiveness of Carbon Fiber Reinforced Plastic (CFRP) sheets on the impact response of reinforced concrete (RC) T-beams, a non-linear finite element model was developed to simulate the structural response of T-beams with CFRP under impact loads. The numerical model was firstly verified by comparing the numerical simulation results with the experimental data, i.e., impact force, reaction force, and mid-span displacement. The strengthening effect of CFRP was analyzed from the section damage evaluation. Then the impact force, mid-span displacement, and failure mode of CFRP-strengthened RC T-beams were studied in comparison with those of un-strengthened T-beams. In addition, the influence of the impact resistance of T-beams strengthened with FRP was investigated in terms of CFRP strengthening mode, CFRP strengthening sizes, CFRP layers and FRP material types. The numerical simulation results indicate that the overall stiffness of the T-beams was improved significantly due to external CFRP strips. Compared with the un-strengthened beam, the maximum mid-span displacement of the CFRP-strengthened beam was reduced by 7.9%. Additionally, the sectional damage factors of the whole span of the CFRP-strengthened beam were reduced to less than 0.3, indicating that the impact resistance of the T-beams was effectively enhanced.

scholarly journals Effect of Novel Spring Damper and Posterior Leaf Spring Ankle Foot Orthosis on the Vertical Component of Ground Reaction Forces During Walking in Patients With Drop Foot

2021 ◽  
Vol 8 (1) ◽  
pp. 17-22
Author(s):  
Ensieh Pourhosaingholi ◽  
◽  
Hassan Saeedi ◽  
Mohammad Kamali ◽  
◽  
...  
Keyword(s):  
Ground Reaction Force ◽  
Impact Force ◽  
Reaction Force ◽  
Vertical Component ◽  
Leaf Spring ◽  
Vertical Force ◽  
The Novel ◽  
Drop Foot ◽  
Vertical Ground Reaction Force ◽  
The Impact

Background: Ankle Foot Orthoses (AFOs) are often prescribed in patients with drop foot. The purpose of this study was to investigate the effect of the novel designed storing-restoring hybrid passive AFO versus Posterior Leaf Spring (PLS) AFO on the peak and timing of vertical component of ground reaction force (vGRF) in patients with drop foot. Objectives: the effect of novel designed storing-restoring hybrid passive AFO versus posterior leaf spring AFO on the peak and timing of Vertical Ground Reaction Force (vGRF) in drop foot patients. Methods: Ten adults with drop foot (7 males and 3 females) were included in this study. Then, these patients walked at a self-selected speed with two AFOs. For each trial, the vGRF components were obtained using a Kistler force plate. Results: the Independent t-test results showed a significant increase in the impact force in spring damper AFO than PLS (p<0.001). Significant differences were also found in the first and third peaks of vertical force and time of occurrence as well as the first minimum force and time of occurrence in spring damper than PLS AFO (p<0.001). Conclusion: the novel AFO affects not only the impact force and peak of vGRF but also the timing of these forces. These changes indicate an improvement in the overall performance of the novel AFO.

Experimental and numerical study of reinforced concrete beams with steel fibers subjected to impact loading

2017 ◽  
Vol 27 (7) ◽  
pp. 1058-1083 ◽  
Author(s):  
Liu Jin ◽  
Renbo Zhang ◽  
Guoqin Dou ◽  
Jiandong Xu ◽  
Xiuli Du
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Impact Loading ◽  
Impact Force ◽  
Numerical Study ◽  
Reaction Force ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Reinforced Concrete Beams ◽  
The Impact

As a kind of impact resistant material, steel fiber reinforced concrete (SFRC) has a good ductility and energy dissipation capacity by improving the tensile strength and impact toughness. To explore the dynamic mechanical behavior of SFRC beams subjected to impact loading, 12 simply-supported SFRC beams with different stirrup ratios (0%, 0.253% and 0.502%) and different volume fractions of steel fibers (0%, 1%, 2% and 3%) were tested with free-falling drop-weights impacting at the mid-span of specimens. The failure patterns were observed and videoed, and simultaneously, the time histories of the impact force, the reaction force, and the mid-span deflection were recorded. Moreover, the influences of stirrup ratio and volume fraction of steel fibers on the impact resistant behavior of the SFRC beams were preliminarily analyzed and discussed. The results indicate that the impact resistant performance of SFRC beams, such as crack pattern, ductility, energy consumption capacity, and deformation recovery capacity can be improved by the addition of steel fibers and stirrups. The required static capacity of these beams were calculated based on the analysis of reaction force vs. displacement loop and impact force vs. displacement loop as well as absorbed energy ratio. For further understanding the experimental results, finite element simulation of SFRC beams subjected to impact loading were carried out. The rationality and accuracy of the finite element model was illustrated by the good agreement between the test observations and the numerical results.

Experimental Study on Dynamic Amplification Factor of Simple-Supported Reinforced Concrete Beams Under Impact Loading Generated by an Impulse Hammer

2020 ◽  
pp. 2150036
Author(s):  
Xue-Qian Wu ◽  
Bo Zhong ◽  
Yang Lv ◽  
Zhong-Xian Li ◽  
Nawawi Chouw
Keyword(s):  
Experimental Study ◽  
Amplification Factor ◽  
Impact Force ◽  
Reaction Force ◽  
Static Force ◽  
Rc Beams ◽  
Dynamic Amplification Factor ◽  
Impact Tests ◽  
Dynamic Amplification ◽  
The Impact

The empirical formulas of dynamic amplification factor (DAF) specified in current bridge codes only consider the span or fundamental frequency of reinforced concrete (RC) girders in highway. Although investigations have been carried out on different bridges with considering the road roughness, vehicle–bridge interactions and travelling velocity, but most of them have been done numerically. In this study, experimental study of DAF was carried out on three simple-supported RC beams with different fundamental frequencies and different damage stages, i.e. without damage, cracked and yielded. Impulse hammer with four hammer heads of different hardness, i.e. black, red, green and brown, were used to generate impact forces with increasing duration. The impact tests were first carried out on the RC beams without any damage by impact hammer with different hammer heads. Then the RC beams were loaded by a concentrated static force at the mid-span to crack. Impact tests with different hammer heads were repeated on the cracked RC beams. Finally, the cracked beams were further loaded by a concentrated static force to yield of the longitudinal reinforcement. The impact tests were repeated on the yielded beams again. Load cells installed at the supports of the RC beams were used to measure the reaction force generated by the hammer, then DAF was calculated directly by dividing the peak reaction force with the peak impact force. Data obtained from tests, theoretical analysis and specification in codes were compared to examine the DAFs. Results show that the ratio of duration of the impact force and the period of the beams performed a significant effect on the DAFs of the beams.

Within-Day Accommodation Effects on Vertical Reaction Forces for Treadmill Running

2002 ◽  
Vol 18 (1) ◽  
pp. 74-82 ◽  
Author(s):  
Scott C. White ◽  
Louise A. Gilchrist ◽  
Kathryn A. Christina
Keyword(s):  
Impact Force ◽  
Statistical Significance ◽  
Reaction Force ◽  
Dependent Measure ◽  
Treadmill Running ◽  
Repeated Measure ◽  
Vertical Force ◽  
Adaptation Period ◽  
Reaction Forces ◽  
The Impact

Prescribing an appropriate adaptation period is an important consideration when using treadmills for locomotion studies. The present study investigated within-trial accommodation to running on a force measuring treadmill. Force measures were derived from vertical reaction force records of 16 runners; 8 were experienced in running on a treadmill. Three dependent measures, the peak impact force (F1), the loading rate of the impact force (LR), and the peak active force (F2) were tested for significant differences (p < 0.05) every 2 minutes of a continuous 20-min run using a two-factor ANOVA (group × time) with one repeated measure (time). Coefficients of variation (CV) for each dependent measure were tested for statistical significance in the same way. There were no significant differences in F1, LR, or F2 over any samples for the 20-min running trials. There were no significant changes in CV values for the duration of the run. The results from the present study suggest that after 30 seconds of treadmill running, there were no significant within-day accommodation effects on vertical force measures over a 20-min treadmill run. Variability between individuals in the consistency of force measures, however, could be a confounding factor. This lack of consistent response for individuals should be considered when exposing participants to experimental designs involving treadmill locomotion.

Biomechanical Factors Affecting the Peak Hand Reaction Force During the Bimanual Arrest of a Moving Mass

2001 ◽  
Vol 124 (1) ◽  
pp. 107-112 ◽  
Author(s):  
Kurt M. DeGoede ◽  
James A. Ashton-Miller ◽  
Albert B. Schultz ◽  
Neil B. Alexander
Keyword(s):  
Sagittal Plane ◽  
Impact Force ◽  
Reaction Force ◽  
Biomechanical Model ◽  
Factors Affecting ◽  
Impact Forces ◽  
Ballistic Pendulum ◽  
Stiffness And Damping ◽  
Biomechanical Factors ◽  
The Impact

Fall-related wrist fractures are among the most common fractures at any age. In order to learn more about the biomechanical factors influencing the impact response of the upper extremities, we studied peak hand reaction force during the bimanual arrest of a 3.4 kg ballistic pendulum moving toward the subject in the sagittal plane at shoulder height. Twenty healthy young and 20 older adults, with equal gender representation, arrested the pendulum after impact at one of three initial speeds: 1.8, 2.3, or 3.0 m/sec. Subjects were asked to employ one of three initial elbow angles: 130, 150, or 170 deg. An analysis of variance showed that hand impact force decreased significantly as impact velocity decreased (50 percent/m/s) and as elbow angle decreased (0.9 percent/degree). A two segment sagittally-symmetric biomechanical model demonstrated that two additional factors affected impact forces: hand-impactor surface stiffness and damping properties, and arm segment mass. We conclude that hand impact force can be reduced by more than 40 percent by decreasing the amount of initial elbow extension and by decreasing the velocity of the hands and arms relative to the impacting surface.

EFFECTS OF WRIST GUARD AND ELBOW ARREST STRATEGY ON IMPACT FORCE IN FORWARD FALLS

2021 ◽  
pp. 2150046
Author(s):  
Yan-Ren Lin ◽  
Chiung-Ling Chen ◽  
Yu-Chi Chen ◽  
Min-Hsien Cho ◽  
Shu-Zon Lou
Keyword(s):  
Loading Rate ◽  
Impact Force ◽  
Reaction Force ◽  
Previous History ◽  
Force Plate ◽  
Wrist Guard ◽  
The Impact ◽  
Forward Falls ◽  
Fall Height ◽  
Peak Impact Force

Wrist guards are widely used for preventing distal radius fracture during in-line skating and snowboard-related activities. However, more than half of people wearing wrist guards nonetheless sustain a fracture of the wrist in forward falls. Accordingly, this study evaluates the effects of three factors, namely the wrist guard design, the fall height and the arrest strategy, on the impact force during a forward fall onto a single outstretched hand. Fifteen physically healthy male participants volunteered for the biomechanical investigation. None of the participants had a previous history of upper extremity injuries or disorders. A 1000[Formula: see text]Hz AMTI force plate was used to measure the ground reaction force (GRF) in forward falls performed using a self-built release system onto a single hand. The GRF and impact time were analyzed in terms of three factors, namely (1) the wrist guard design, including bare hand (BH), conventional wrist guard (WG), wrist guard pad on palm (WG+), and WG+ with no lower splint (WG[Formula: see text]; (2) the elbow arrest strategy, including elbow extended and elbow flexed; and (3) the fall height, including 4[Formula: see text]cm and 8[Formula: see text]cm. The impact force and loading rate significantly increased with an increasing fall height. However, the elbow flexed strategy attenuated the GRF peak force and delayed the point of peak impact force. The GRF in the WG, WG+ and WG− conditions was significantly lower than that in the BH condition. Overall, a lower fall height, a wrist guard with a compliant pad (WG+ or WG[Formula: see text], and an elbow flexed strategy reduced the impact force, delayed the peak impact force, and reduced the loading rate in forward falls.

scholarly journals THE EFFECT OF KNEE POSTURES AND CUSHIONS IN THE LOAD TRANSMISSION OF IMPACT LOADING - AN IN VITRO BIOMECHANICAL PORCINE MODEL

2004 ◽  
Vol 16 (04) ◽  
pp. 165-172
Author(s):  
JAW-LIN WANG ◽  
YEN-LIN LEE
Keyword(s):  
Knee Joint ◽  
Impact Loading ◽  
Shear Force ◽  
Mechanical Response ◽  
Impact Force ◽  
Reaction Force ◽  
Bending Moment ◽  
Shock Attenuation ◽  
Neutral Posture ◽  
The Impact

Degenerative osteoarthritis is the consequence of impact force applied to articular cartilage that results in surface fissuring. Soft cushions and flexed posture are two important factors to reduce the impact force; however, no quantitative information of how soft should the cushion be to prevent the injury and the mechanism of force attenuation of knee joint at neutral and flexed posture was not well documented yet. The objective of current study is hence to find the quantitative shock attenuation of knee joint using different stiffness of cushions when the knee is at neutral posture and flexed posture. A “drop-tower type” impact apparatus was used for testing. Nineteen fresh porcine knee joints were divided into two posture groups, i.e. neutral and flexed posture. All specimens were tested using stiff, medium, and soft cushions. The axial reaction force, anteroposterior shear force, and flexion bending moment were recorded for analysis. We found the flexed posture decreased the axial reaction force and anterior shear force but increased the flexion bending moment. The effect of stiffness of cushions on the mechanical response of knee joint during impact loading was significant for neutral posture but not for flexed posture.

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