Investigation into Hand Impact Force During Forward Falls on Uneven Terrain

Author(s):  
Saeed Abdolshah ◽  
Nader Rajaei ◽  
Yasuhiro Akiyama ◽  
Yoji Yamada ◽  
Shogo Okamoto
10.5772/7238 ◽  
2009 ◽  
Vol 6 (3) ◽  
pp. 25 ◽  
Author(s):  
Moyuru Yamada ◽  
Shigenori Sano ◽  
Naoki Uchiyama

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.


2003 ◽  
Vol 18 (8) ◽  
pp. 730-736 ◽  
Author(s):  
J Lo ◽  
G.N McCabe ◽  
K.M DeGoede ◽  
H Okuizumi ◽  
J.A Ashton-Miller

Author(s):  
Yan-Ren Lin ◽  
Chiung-Ling Chen ◽  
Yu-Chi Chen ◽  
Min-Hsien Cho ◽  
Shu-Zon Lou

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.


2000 ◽  
Vol 10 (PR9) ◽  
pp. Pr9-185-Pr9-190
Author(s):  
K. Ogawa ◽  
T. Yokoyama

2019 ◽  
Vol 7 (2) ◽  
pp. 205-213
Author(s):  
Yong-Doo Kim ◽  
Seung-Jae Lim ◽  
Hyun-Ung Bae ◽  
Kyoung-Ju Kim ◽  
Chin-Ok Lee ◽  
...  
Keyword(s):  

Author(s):  
Ulrich Leuthäusser

In sport climbing, a common method of belaying is to use a static rope brake attached to the belayer’s harness, but the belayer can move freely. This paper investigates the dynamics of a climbing fall with such a belayer. The dynamics are nontrivial because of the belayer’s constraint to be always at or above his initial position. An exact solution for a linear elastic rope is presented. Compared to a fix-point belay, one obtains a considerable force reduction on the belay-chain. However, there is a trade-off of a longer stopping distance of both climber and belayer. In order to calculate the stopping distance, friction between rope and the top carabiner has been taken into account. Closed-form formulas allow for calculating the maximum impact force, as well as the minimum mass of the belayer which is necessary to hold a fall from a certain height.


2022 ◽  
Vol 162 ◽  
pp. 107983
Author(s):  
Junjiang Liu ◽  
Baijie Qiao ◽  
Yuanchang Chen ◽  
Yuda Zhu ◽  
Weifeng He ◽  
...  

2021 ◽  
Vol 60 (1) ◽  
pp. 145-157
Author(s):  
Yi Luo ◽  
Ke Yuan ◽  
Lumin Shen ◽  
Jiefu Liu

Abstract In this study, a series of in-plane hexagonal honeycombs with different Poisson's ratio induced by topological diversity are studied, considering re-entrant, semi-re-entrant and convex cells, respectively. The crushing strength of honeycomb in terms of Poisson's ratio is firstly presented. In the previous research, we have studied the compression performance of honeycomb with different negative Poisson's ratio. In this study, a comparative study on the local impact resistance of different sandwich panels is conducted by considering a spherical projectile with low to medium impact speed. Some critical criteria (i.e. local indentation profile, global deflection, impact force and energy absorption) are adopted to analyze the impact resistance. Finally, an influential mechanism of Poisson's ratio on the local impact resistance of sandwich panel is studied by considering the variation of core strength and post-impact collapse behavior.


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