Identifying Gait Patterns for Dynamically Stable Walking

2004 ◽  
Author(s):  
Abhishek Agrawal ◽  
Sunil K. Agrawal
Keyword(s):  
Dynamic Stability ◽  
Gait Cycle ◽  
Human Motion ◽  
Degree Of Freedom ◽  
Stability Criteria ◽  
Gait Patterns ◽  
Novel Approach ◽  
Periodic Property ◽  
Stable Gait ◽  
Six Degree Of Freedom

We anticipate that the motion of biped machines should be similar to human motion to achieve dynamic stability. In this paper, a novel approach to compute dynamically stable gait of a planar six degree-of-freedom biped is presented. This approach is analytical and is based on periodic property of a gait cycle. The resulting gait satisfies all dynamic stability criteria.

An Approach to Identify Joint Motions for Dynamically Stable Walking

2005 ◽  
Vol 128 (3) ◽  
pp. 649-653 ◽  
Author(s):  
Abhishek Agrawal ◽  
Sunil K. Agrawal
Keyword(s):  
Dynamic Stability ◽  
Biped Robot ◽  
Degree Of Freedom ◽  
Stability Criteria ◽  
Biped Robots ◽  
Wheeled Robots ◽  
Novel Approach ◽  
Six Degree Of Freedom ◽  
Joint Motions

Biped robots are more versatile than conventional wheeled robots, but they tend to tip over easily. The dynamic stability of a biped robot needs to be maintained during walking. In this paper, a novel approach to compute dynamically stable walking motions of a planar six degree-of-freedom biped is presented. This approach is analytical and is based on the need for periodicity of the motion. The resulting gait satisfies the dynamic stability criteria. Sets of joint motions for different step sizes and speed of walking, i.e., quasi-statically and dynamically stable walking patterns, can be obtained.

Altering Footwear Type Influences Gait During Level Walking and Downhill Transitions

2012 ◽  
Vol 28 (5) ◽  
pp. 481-490 ◽  
Author(s):  
Keith A. Stern ◽  
Jinger S. Gottschall
Keyword(s):  
Gait Cycle ◽  
Dynamic Balance ◽  
Step Length ◽  
Lower Leg ◽  
Step Width ◽  
Lateral Gastrocnemius ◽  
Gait Patterns ◽  
Level Walking ◽  
Stance Time ◽  
Stable Gait

The purpose of our study was to determine if altering the insoles within footwear or walking barefoot, as an attempt to increase or decrease cutaneous stimuli, would improve dynamic balance during a hill-walking task. We hypothesize that compared with foam insoles or iced bare feet, textured insoles or bare feet will result in greater speeds, longer step lengths, narrower step width, shorter stance time, and less tibialis anterior (TA), soleus (SOL), and lateral gastrocnemius (LG) activity during key gait cycle phases. Ten, healthy college students, 5 men and 5 women, completed the protocol that consisted of level walking and downhill transition walking in five different footwear insole or barefoot conditions. During level walking, conditions with the hypothesized greater cutaneous stimuli resulted in greater step length, which relates to a more stable gait. In detail, the texture insole condition average step length was 3% longer than the regular insole condition, which was 5% longer than the ice condition (p < .01). The same signals of increased stability were evident during the more challenging downhill transition stride. Step length during the barefoot condition was 8% longer than the ice condition (p < .05) and step width during the regular footwear condition was 5% narrower than the foam condition (p = .05). To add, during the preswing phase of level walking, TA activity of the textured insole condition was 30% less than the foam insole. Although our data show that footwear conditions alter gait patterns and lower leg muscle activity during walking, there is not enough evidence to support the hypothesis that textured insoles will improve dynamic balance as compared with other footwear types.

Parallel Computational Algorithms for the Kinematics and Dynamics of Planar and Spatial Parallel Manipulators

1996 ◽  
Vol 118 (1) ◽  
pp. 22-28 ◽  
Author(s):  
C. M. Gosselin
Keyword(s):  
Inverse Kinematics ◽  
Parallel Manipulator ◽  
Inverse Dynamics ◽  
Parallel Manipulators ◽  
Degree Of Freedom ◽  
Kinematic Chains ◽  
Novel Approach ◽  
Judicious Choice ◽  
Six Degree Of Freedom ◽  
Three Degree Of Freedom

This paper introduces a novel approach for the computation of the inverse dynamics of parallel manipulators. It is shown that, for this type of manipulator, the inverse kinematics and the inverse dynamics procedures can be easily parallelized. The result is a closed-form efficient algorithm using n processors, where n is the number of kinematic chains connecting the base to the end-effector. The dynamics computations are based on the Newton-Euler formalism. The parallel algorithm arises from a judicious choice of the coordinate frames attached to each of the legs, which allows the exploitation of the parallel nature of the mechanism itself. Examples of the application of the algorithm to a planar three-degree-of-freedom parallel manipulator and to a spatial six-degree-of-freedom parallel manipulator are presented.

DYNAMIC STABILITY OF FOILBORNE HYDROFOIL/SWATH WITH ANHEDRAL FOIL CONFIGURATION

2017 ◽  
Vol 159 (B2) ◽  
Author(s):  
S Williams ◽  
S Brizzolara
Keyword(s):  
Vehicle Dynamics ◽  
High Speed ◽  
Degree Of Freedom ◽  
Design Criteria ◽  
Vehicle Stability ◽  
Configuration Design ◽  
Stability Criteria ◽  
Preliminary Assessment ◽  
Displacement Mode ◽  
Six Degree Of Freedom

The hybrid hydrofoil/SWATH (Small Waterplane Area Twin Hull) designed and patented by Stefano Brizzolara, is a novel vehicle that is optimized to operate in both a high-speed foilborne mode and a displacement mode. The deployable hydrofoils on the vehicle take on a unique four surface piercing anhedral foil configuration. This foilborne design had previously undergone only preliminary assessment of stability characteristics. A six degree of freedom model of the foilborne vehicle dynamics is introduced as a framework to study vehicle stability and maneuvering. Stability criteria derived from multiple linearized models of the vehicle dynamics are compared to the six degree of freedom results in both the vertical and horizontal planes. Foil configuration design criteria are developed for pitch equilibrium, pitch stability, and directional stability.

Iterative feedback control based on frequency response model for a six-degree-of-freedom micro-vibration platform

2021 ◽  
pp. 107754632199731
Author(s):  
He Zhu ◽  
Shuai He ◽  
Zhenbang Xu ◽  
XiaoMing Wang ◽  
Chao Qin ◽  
...  
Keyword(s):  
Feedback Control ◽  
Frequency Response ◽  
Control Strategy ◽  
Degree Of Freedom ◽  
Small Displacement ◽  
Response Model ◽  
Parameter Uncertainties ◽  
Micro Vibration ◽  
Six Degree Of Freedom ◽  
Iterative Feedback

In this article, a six-degree-of-freedom (6-DOF) micro-vibration platform (6-MVP) based on the Gough–Stewart configuration is designed to reproduce the 6-DOF micro-vibration that occurs at the installation surfaces of sensitive space-based instruments such as large space optical loads and laser communications equipment. The platform’s dynamic model is simplified because of the small displacement characteristics of micro-vibrations. By considering the multifrequency line spectrum characteristics of micro-vibrations and the parameter uncertainties, an iterative feedback control strategy based on a frequency response model is designed, and the effectiveness of the proposed control strategy is verified by performing integrated simulations. Finally, micro-vibration experiments are performed with a 10 kg load on the platform. The results of these micro-vibration experiments show that after several iterations, the amplitude control errors are less than 3% and the phase control errors are less than 1°. The control strategy presented in this article offers the advantages of a simple algorithm and high precision and it can also be used to control other similar micro-vibration platforms.

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