Effects of head and tail as swinging appendages on the dynamic walking performance of a quadruped robot

Robotica ◽  
2016 ◽  
Vol 34 (12) ◽  
pp. 2878-2891 ◽  
Author(s):  
Xiuli Zhang ◽  
Jiaqing Gong ◽  
Yanan Yao
Keyword(s):  
Stride Length ◽  
Pattern Generator ◽  
Flight Time ◽  
Quadruped Robot ◽  
Ground Reaction Forces ◽  
Reaction Forces ◽  
Fixed Phase ◽  
Walking Performance ◽  
Hopf Oscillator ◽  
Phase Differences

SUMMARYWe designed a quadruped robot with a one-degree-of-freedom (1-DOF)-pitch head, a 1-DOF-roll tail, and 14 active DOFs in total, which are controlled via a central pattern generator (CPG) based on a Hopf oscillator. Head and tail movements are coupled to the leg movements with fixed phase differences. Experiments show that tail swinging in roll can equilibrate feet–ground reaction forces (GRF), reducing yaw errors and enabling the robot to maintain its direction when trotting. Head swing in pitch has the potential to increase flight time and stride length of the swinging legs and increase the robot's forward velocity when running in bounds.

Sex and stride length impact leg stiffness and ground reaction forces when running with body borne load

2019 ◽  
Vol 86 ◽  
pp. 96-101 ◽  
Author(s):  
Nicholas J. Lobb ◽  
AuraLea C. Fain ◽  
Kayla D. Seymore ◽  
Tyler N. Brown
Keyword(s):  
Stride Length ◽  
Ground Reaction Forces ◽  
Leg Stiffness ◽  
Reaction Forces

An Instrument That Simultaneously Measures Spatiotemporal Gait Parameters and Ground Reaction Forces of Locomoting Rats

2008 ◽  
Author(s):  
U. Tasch ◽  
P. Moubarak ◽  
W. Tang ◽  
L. Zhu ◽  
R. M. Lovering ◽  
...  
Keyword(s):  
Stride Length ◽  
Vertical Direction ◽  
Ground Reaction Forces ◽  
Gait Parameters ◽  
Load Cells ◽  
Floor Vibrations ◽  
Reaction Forces ◽  
Models Of Injury ◽  
Vertical Ground

We describe an instrument that assesses two features of the gait of rats, spatiotemporal paw movement variables (SPMV) and ground reaction forces (GRF) in the vertical direction. The GRF and the SPMV variables are measured electrically by eight single axis load-cells that support two floor plates. We can derive four gait parameters from the SPMV and GRF measured by the instrument: the stride length of individual limbs, the maximum and mean vertical ground forces, and the intensity of the vibrations created by each paw during locomotion. Measurements of the vertical GRF show errors of less than 3.5%; errors in the determination of the paw positions, used to derive stride lengths, are less than 9 mm. Here we report the stride length, maximum and mean GRF values, and the intensity of the floor vibrations of healthy adult mature rats. Our instrument is capable of evaluating changes in these gait parameters in rat models of injury and disease.

A Dynamic Analysis Based on MBD ADAMS Program for a Variant of Quadruped Robot

2016 ◽  
Vol 823 ◽  
pp. 429-434 ◽  
Author(s):  
Florina Pop ◽  
Erwin Christian Lovasz ◽  
Valer Dolga ◽  
Marco Ceccarelli ◽  
Dan Mărgineanu ◽  
...  
Keyword(s):  
Dynamic Analysis ◽  
3D Model ◽  
Quadruped Robot ◽  
Moment Of Inertia ◽  
Ground Reaction Forces ◽  
Generalized Coordinates ◽  
Mass Moment ◽  
Adams Software ◽  
Mass Moment Of Inertia ◽  
Reaction Forces

For stability and impact reaction forces assessment of a quadruped robot during walking, a dynamic analysis is considered. For this purpose, a variant of a quadruped robot based on Jansen mechanism is presented. For interpreting the influence of the reaction forces from the ground during walking, the analysis was conducted with help of ADAMS software using a 3D model of the robot. Material specifications, forces and moments acting in the robot structure were considered. Graphical results obtained regarding the ground reaction forces are displayed. Also a reduced mass moment of inertia at the crankshaft is taken into consideration based on Lagrange motion equation and generalized coordinates.

scholarly journals Gait Disturbances in Dystrophic Hamsters

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Thomas G. Hampton ◽  
Ajit Kale ◽  
Ivo Amende ◽  
Wenlong Tang ◽  
Scott McCue ◽  
...  
Keyword(s):  
Animal Model ◽  
Muscular Dystrophy ◽  
Stride Length ◽  
Ground Reaction Forces ◽  
Functional Aspects ◽  
Reaction Forces ◽  
Gait Abnormalities ◽  
Gait Disturbances ◽  
Quantitative Gait Analysis ◽  
Treadmill Belt

The delta-sarcoglycan-deficient hamster is an excellent model to study muscular dystrophy. Gait disturbances, important clinically, have not been described in this animal model. We applied ventral plane videography (DigiGait) to analyze gait in BIO TO-2 dystrophic and BIO F1B control hamsters walking on a transparent treadmill belt. Stride length was~13% shorter () in TO-2 hamsters at 9 months of age compared to F1B hamsters. Hindlimb propulsion duration, an indicator of muscle strength, was shorter in 9-month-old TO-2 ( ms) compared to F1B hamsters ( ms; ). Braking duration, reflecting generation of ground reaction forces, was delayed in 9-month-old TO-2 ( ms) compared to F1B hamsters ( ms; ). Hindpaw eversion, evidence of muscle weakness, was greater in 9-month-old TO-2 than in F1B hamsters ( versus ; ). Incline and decline walking aggravated gait disturbances in TO-2 hamsters at 3 months of age. Several gait deficits were apparent in TO-2 hamsters at 1 month of age. Quantitative gait analysis demonstrates that dystrophic TO-2 hamsters recapitulate functional aspects of human muscular dystrophy. Early detection of gait abnormalities in a convenient animal model may accelerate the development of therapies for muscular dystrophy.

scholarly journals Low strength is related to diminished ground reaction forces and walking performance in older women

2011 ◽  
Vol 33 (4) ◽  
pp. 668-672 ◽  
Author(s):  
Dain P. LaRoche ◽  
Erica D. Millett ◽  
Rachel J. Kralian
Keyword(s):  
Older Women ◽  
Ground Reaction Forces ◽  
Reaction Forces ◽  
Walking Performance ◽  
Low Strength

scholarly journals The compliant effect of controlled spine on interaction with the ground in quadruped trotting

2019 ◽  
Vol 234 (1) ◽  
pp. 27-45 ◽  
Author(s):  
Zhang Li ◽  
Yuegang Tan ◽  
Ping Wu ◽  
Shun Zeng
Keyword(s):  
High Speed ◽  
Lumbar Vertebra ◽  
Quadruped Robot ◽  
Ground Reaction Forces ◽  
Gait Simulation ◽  
Compliant Control ◽  
Reaction Forces ◽  
Motion Performance ◽  
The Stability ◽  
Flat Ground

The spine plays important roles in the quadruped locomotion. These effects not only stand out in high-speed gait but also function in low-speed gait, especially the transition gait – trotting gait. In order to investigate the effects of the spine on the motion performance of the quadruped trotting, the spine with two joints is applied into the structure of the quadruped robot. This structure is inspired from the analyses for the canine, which imitates the configuration of thoracic vertebra, front lumbar vertebra and hind lumbar vertebra. Different from the quadruped robot with the passive spine or the active spine by inputting position, a compliant control is applied to the spinal joints. The feature of force control not only possesses the soft feature of the passive spine but also has the advantage of enlarging the motion ability. In the simulation process, a large amount of analyses are carried out including the influence of the control parameters of the controlled spine, the comparison with the quadruped robot with rigid torso and the gait simulation when the robot moves on the flat ground and across an obstacle. The results reveal that the controlled spine has an excellent compliant effect on the interaction with the ground. It contributes to reducing the ground reaction forces; meanwhile, the compliant effect is beneficial for improving the stability. By establishing the prototype robot and performing the motion experiment, the compliant effect of the spine is proven effective.

Kinematic and dynamic simulation of an octopod robot controlled by different central pattern generators

2018 ◽  
Vol 233 (4) ◽  
pp. 400-417 ◽  
Author(s):  
Dariusz Grzelczyk ◽  
Olga Szymanowska ◽  
Jan Awrejcewicz
Keyword(s):  
Dynamic Simulation ◽  
Central Pattern Generators ◽  
Pattern Generator ◽  
Ground Reaction Forces ◽  
Walking Robot ◽  
Centre Of Gravity ◽  
Reaction Forces ◽  
Mechanical Oscillators ◽  
Pattern Generators ◽  
Central Pattern Generator Model

The goal of the study was to perform both kinematic and dynamic simulation of an octopod robot walking on a flat and hard surface. To drive robot legs, different non-linear mechanical oscillators were employed as central pattern generators. Aside from using some well-known oscillators, a new model was proposed. Time series of robot’s kinematic and dynamic locomotion parameters were computed and discussed. Displacement and velocity of the centre of gravity of the robot, ground reaction forces acting on the robot legs, as well as some aspects of energy consumption of a walking robot were analysed to assess the central pattern generators. The obtained kinematic and dynamic parameters showed some advantages of the applied generator. In particular, the gait of the robot was most stable when the robot was driven by the proposed central pattern generator model.

scholarly journals Running ground reaction forces across footwear conditions are predicted from the motion of two body mass components

2019 ◽  
Vol 126 (5) ◽  
pp. 1315-1325 ◽  
Author(s):  
Andrew B. Udofa ◽  
Kenneth P. Clark ◽  
Laurence J. Ryan ◽  
Peter G. Weyand
Keyword(s):  
Ground Reaction Force ◽  
Lower Limb ◽  
Reaction Force ◽  
Ground Reaction Forces ◽  
Vertical Ground Reaction Force ◽  
Time Patterns ◽  
Foot Strike ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Force Time

Although running shoes alter foot-ground reaction forces, particularly during impact, how they do so is incompletely understood. Here, we hypothesized that footwear effects on running ground reaction force-time patterns can be accurately predicted from the motion of two components of the body’s mass (mb): the contacting lower-limb (m1 = 0.08mb) and the remainder (m2 = 0.92mb). Simultaneous motion and vertical ground reaction force-time data were acquired at 1,000 Hz from eight uninstructed subjects running on a force-instrumented treadmill at 4.0 and 7.0 m/s under four footwear conditions: barefoot, minimal sole, thin sole, and thick sole. Vertical ground reaction force-time patterns were generated from the two-mass model using body mass and footfall-specific measures of contact time, aerial time, and lower-limb impact deceleration. Model force-time patterns generated using the empirical inputs acquired for each footfall matched the measured patterns closely across the four footwear conditions at both protocol speeds ( r2 = 0.96 ± 0.004; root mean squared error  = 0.17 ± 0.01 body-weight units; n = 275 total footfalls). Foot landing angles (θF) were inversely related to footwear thickness; more positive or plantar-flexed landing angles coincided with longer-impact durations and force-time patterns lacking distinct rising-edge force peaks. Our results support three conclusions: 1) running ground reaction force-time patterns across footwear conditions can be accurately predicted using our two-mass, two-impulse model, 2) impact forces, regardless of foot strike mechanics, can be accurately quantified from lower-limb motion and a fixed anatomical mass (0.08mb), and 3) runners maintain similar loading rates (ΔFvertical/Δtime) across footwear conditions by altering foot strike angle to regulate the duration of impact. NEW & NOTEWORTHY Here, we validate a two-mass, two-impulse model of running vertical ground reaction forces across four footwear thickness conditions (barefoot, minimal, thin, thick). Our model allows the impact portion of the impulse to be extracted from measured total ground reaction force-time patterns using motion data from the ankle. The gait adjustments observed across footwear conditions revealed that runners maintained similar loading rates across footwear conditions by altering foot strike angles to regulate the duration of impact.

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