3D guidance for vertical impact on non-stationary targets

2012 ◽  
Author(s):  
Jinpeng Zhang ◽  
Youliang Cao ◽  
Xiaona Song ◽  
Minglian Zhang ◽  
Gongzhang Shen
Keyword(s):  
3D Guidance ◽  
Vertical Impact

scholarly journals Deep Portrait Lighting Enhancement with 3D Guidance

2021 ◽  
Vol 40 (4) ◽  
pp. 177-188
Author(s):  
Fangzhou Han ◽  
Can Wang ◽  
Hao Du ◽  
Jing Liao
Keyword(s):  
3D Guidance

Influence of Attached Masses on Impact Forces and Running Style in Heel-Toe Running

1987 ◽  
Vol 3 (3) ◽  
pp. 264-275 ◽  
Author(s):  
Alexander Bahlsen ◽  
Benno M. Nigg
Keyword(s):  
Body Mass ◽  
High Speed ◽  
Impact Force ◽  
Force Plate ◽  
The Body ◽  
Additional Mass ◽  
Impact Forces ◽  
Running Shoes ◽  
High Speed Film ◽  
Vertical Impact

Impact forces analysis in heel-toe running is often used to examine the reduction of impact forces for different running shoes and/or running techniques. Body mass is reported to be a dominant predictor of vertical impact force peaks. However, it is not evident whether this finding is only true for the real body mass or whether it is also true for additional masses attached to the body (e.g., running with additional weight or heavy shoes). The purpose of this study was to determine the effect of additional mass on vertical impact force peaks and running style. Nineteen subjects (9 males, 10 females) with a mean mass of 74.2 kg/56.2 kg (SD = 10.0 kg and 6.0 kg) volunteered to participate in this study. Additional masses were attached to the shoe (.05 and .1 kg), the tibia (.2, .4, .6 kg), and the hip (5.9 and 10.7 kg). Force plate measurements and high-speed film data were analyzed. In this study the vertical impact force peaks, Fzi, were not affected by additional masses, the vertical active force peaks, Fza, were only affected by additional masses greater than 6 kg, and the movement was only different in the knee angle at touchdown, ϵ0, for additional masses greater than .6 kg. The results of this study did not support findings reported earlier in the literature that body mass is a dominant predictor of external vertical impact force peaks.

3D Nonlinear Guidance Law for Bank-to-Turn Missile

2011 ◽  
Vol 317-319 ◽  
pp. 727-733
Author(s):  
Shuang Chun Peng ◽  
Liang Pan ◽  
Tian Jiang Hu ◽  
Lin Cheng Shen
Keyword(s):  
Three Dimensional ◽  
Lyapunov Theory ◽  
Line Of Sight ◽  
Rate Model ◽  
Guidance Law ◽  
Terminal Constraints ◽  
Guidance Laws ◽  
3D Guidance ◽  
Guidance Model ◽  
Vector Description

A new three-dimensional (3D) nonlinear guidance law is proposed and developed for bank-to-turn (BTT) with motion coupling. First of all, the 3D guidance model is established. In detail, the line-of-sight (LOS) rate model is established with the vector description method, and the kinematics model is divided into three terms of pitching, swerving and coupling, then by using the twist-based method, the LOS direction changing model is built for designing the guidance law with terminal angular constraints. Secondly, the 3D guidance laws are designed with Lyapunov theory, corresponding to no terminal constraints and terminal constraints, respectively. And finally, the simulation results show that the proposed guidance law can effectively satisfy the guidance precision requirements of BTT missile.

A nonlinear occupant-restraint system model for predicting human injuries caused by vertical impact

2021 ◽  
Author(s):  
Di Zhou ◽  
Xianhui Wang ◽  
Qichen Zheng ◽  
Tiaoqi Fu ◽  
Mengyang Wu ◽  
...  
Keyword(s):  
System Model ◽  
Restraint System ◽  
Occupant Restraint System ◽  
Vertical Impact

scholarly journals Contact Response Analysis of Vertical Impact between Elastic Sphere and Elastic Half Space

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Yang Yang ◽  
Qingliang Zeng ◽  
Lirong Wan
Keyword(s):  
Rigid Body ◽  
Half Space ◽  
Contact Process ◽  
Elastic Half Space ◽  
Metal Plate ◽  
3D Simulation ◽  
Elastic Sphere ◽  
Research Results ◽  
Contact Response ◽  
Vertical Impact

At present, the contact problem between the particle and the plane plate is generally equivalent to the rigid sphere impacting the elastic half space or the elastic sphere impacting the rigid surface. However, in the actual contact process, there will be no rigid body, and both contact and contacted object will deform and absorb energy. The research results obtained from the equivalent of the contact material to the rigid body are less accurate. In order to obtain the accurate mechanical relation and contact response, we took the research of impact between particles and the metal plate as a breakthrough in which the particle is equivalent to an elastic sphere and the metal plate is equivalent to an elastic half space and established the theory of vertical impact contact between elastic sphere and elastic half space by the Hertz contact theory. Through the dynamic simulation of an elastic sphere which has similar properties with rock impacting target in elastic half space in LS-DYNA, the correctness of the established theory and the feasibility of the contact process simulated by LS-DYNA are verified. Based on the established theory and 3D simulation, we studied the influence law of material parameters on the contact response and analyzed the differences of the collision vibration signals caused by the different contact objects. From the above research results, we obtain that the theoretical model is more accurate to predict the maximum contact force and contact displacement in this paper than traditional Hertz theory. And the sphere radius and both contact objects’ elastic modulus have larger influence on the contact response than sphere density, while the Poisson’s ratio has the smallest influence on the contact response results. Different material properties will cause the different contact response. The conclusions of this paper provide a theoretical calculation method for contact and a 3D simulation method for elastic half space and provide theoretical guidance for the differences analysis of the vibration signal.

scholarly journals Role of disc area and trabecular bone density on lumbar spinal column fracture risk curves under vertical impact

2018 ◽  
Vol 72 ◽  
pp. 90-98 ◽  
Author(s):  
Narayan Yoganandan ◽  
Jason Moore ◽  
Frank A. Pintar ◽  
Anjishnu Banerjee ◽  
Nicholas DeVogel ◽  
...  
Keyword(s):  
Bone Density ◽  
Fracture Risk ◽  
Trabecular Bone ◽  
Spinal Column ◽  
Trabecular Bone Density ◽  
Disc Area ◽  
Lumbar Spinal ◽  
Risk Curves ◽  
Vertical Impact

Miscellaneous Studies in Hard-Hammer Percussion Flaking: The Effects of Oblique Impact

1975 ◽  
Vol 40 (2Part1) ◽  
pp. 203-207 ◽  
Author(s):  
John D. Speth
Keyword(s):  
Impact Angle ◽  
Oblique Impact ◽  
Steel Balls ◽  
Vertical Impact

Steel balls were dropped on to massive glass prisms at an impact angle of 45° in order to determine the effects of oblique impact on several attributes of flake size and flake shape. The results indicate that a flake produced by oblique impact is shorter, but not significantly thinner (except in the immediate area of the cone), than a flake of comparable platform thickness produced by vertical impact.

scholarly journals Forefoot Striking Is More Effective in Reducing Loadrates than Increasing Cadence in Runners

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0005
Author(s):  
Erin Futrell ◽  
Irene Davis
Keyword(s):  
Repeated Measures ◽  
Auditory Signal ◽  
Gait Retraining ◽  
Loading Rates ◽  
Impact Forces ◽  
Running Injuries ◽  
Main Effects ◽  
Wireless Accelerometer ◽  
One Way Anova ◽  
Vertical Impact

Category: Sports Introduction/Purpose: Vertical impact forces are highly influenced by the way the foot contacts the ground. These impact forces are associated with high loading rates which have been related to running injuries. As a result, clinicians have begun to use gait retraining interventions to reduce loadrates and prevent future impact-related injuries. Two types of gait retraining techniques have been promoted to reduce excessive running impacts. The first involves increasing cadence (CAD), or number of steps per minute, by 5-10%, thereby reducing stride length. The second type of gait retraining involves landing on the ball of the foot at ground contact, or using a forefoot strike (FFS). Both of these gait-retraining styles have been reported to reduce impacts, but they have not been compared with each other. Methods: 33 healthy runners (9M, 24F), running 5-15 mpw, with a rearfoot strike pattern with cadence < 170 steps/min were recruited. Subjects were randomly allocated to either FFS or CAD retraining. All subjects underwent an 8-session gait retraining program (over 2-3 wks) with auditory feedback on a treadmill. The CAD group ran to a digital metronome to increase cadence by 7.5%. The FFS group wore a wireless accelerometer that provided an auditory signal on footstrike pattern. A gait analysis was conducted at baseline, 1 wk, 1 month, and 6 months. Variables included vertical average and instantaneous load rates (VALR, VILR). A 2 x 4 repeated measures ANOVA was used to compare differences within and between the CAD and FFS groups at baseline, 1 week, 1 month and 6 months post retraining. For variables with significant interactions, simple main effects of group, as well as time were further explored using one-way ANOVA Results: There were significant interaction effects of time*group for VALR (p= 0.001), VILR (p=0.001) and foot angle (p< 0.001), but not cadence. For the simple main effects for the CAD group, VALR reduced by 14%, 7% and 16% at 1 week, 1 month, and 6 months post gait retraining respectively, compared with baseline (Figure 1). However, these reductions were not significant. For the FFS group, VALR was significantly reduced by 50%, 51% and 51% at 1 week, 1 month, and 6 months post gait retraining respectively. Interestingly, both the CAD and FFS groups increased cadence by similar amounts. Conclusion: Transitioning to a FFS pattern is significantly more effective than increasing CAD when reducing vertical loadrate (both VALR and VILR) is the goal. These changes persisted out to 6 months post gait retraining, suggesting permanence of the new pattern.

Vertical impact increase in middle age may explain idiopathic weight-bearing joint osteoarthritis

2001 ◽  
Vol 82 (12) ◽  
pp. 1673-1677 ◽  
Author(s):  
Steven Robbins ◽  
Edward Waked ◽  
Nicholas Krouglicof
Keyword(s):  
Middle Age ◽  
Weight Bearing ◽  
Vertical Impact
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