Human walking is quite stereotypical and is composed mainly by two phases: the swing phase, in which the foot advances in a step, and the stance phase in which the foot contacts the ground. It has been observed that a trip during the swing phase (of the right leg in the drawing) triggers one of two types of initial recovery strategies (or more precisely reactions):1) an elevating strategy which is characterized by an immediate rise of the foot following the trip, a longer step and more time for next foot contact2) a lowering strategy, characterized by quick lowering of foot and contact with the ground with realization of a short stepThe elevating strategy is usually observed when trip occurs in the beginning of the swing phase whereas the lowering strategy is commonly observed when trip occurs in mid or late swing.Parameters like walking speed, trunk inclination and positioning and timing of next foot contact after trip have been associated with the success of the recovery attempt. One of the main goals is avoiding a critical trunk inclination which could cause a fall. This is achieved by applying a counteracting external moment to decelerate forward inclination of the body. Because external moment is due exclusively to foot-ground interaction and this contact is unilateral, positioning of frontal foot is essential for the ability of applying a counteracting moment and decelerate forward inclination of trunk. An insufficient distance between front foot and CM of the body will either lead to a fall or require further steps in a multiples step recovery strategy.
Biomechatronics lab. Escola Politecnica. University of São Paulo. Brazil
• Models of the human motor control system
from a control engineering perspective
Members• Prof. Tarcisio H. Coelho
• Prof. Oswaldo Horikawa
• Luis Filipe Rossi
• Reinaldo de Bernardi
• Prof. Liu
• Aline Arcanjo
• Carlos Noriega
• Virginia H. Quadrado
• Andrey Bugarin
• Milton Cortez Junior
• Masanori Ishizawa
• Gabriel Reis
• Mateus Dias
• Marcelo Slyzt
• Rafael S. Souza
• Rodrigo M. Carnier
• Rodrigo M. Otake
Prof. Hermano I. Krebs. MIT (EUA)
Prof T. Komeda . Shibaura Inst.
Juan Alvaro Gallego CSIC (Spain)
Prof. Sergio T. Rodrigues UNESP.
Prof. Marko Ackermann, FEI.
Prof. Linamara R. Battistella
Prof. Adriano Siqueira
Prof. Glauco Caurin
Prof. Gustavo Goroso
Prof. Michele Schultz
Prof. Mario Pedrazzolli
• Human gait on irregular environments
Technique to analyse biped robot stability (Basin of Attraction)
– Biped gait stability
– Human motor control models
Forner-Cordero A; van der Helm FCT;
Koopman B. (2006) Describing gait as a
sequence of states.
Journal of Biomechanics 39:948-957
MSc R. de Bernardi,
Prof. J.J. Da Cruz
Biped robot stability
L.F. Rossi (PhD)
Normal Gait and Reactions to Perturbations
Eng et al, 1994 Exp Brain Res, 102.
Forner Cordero et al, 2004. Biol. Cyb. 91(4):212-22
Trip in the swing phase triggers either:
1) an elevating strategy (long step + longer time)
2) a lowering strategy (short step + shorter time)
Click for video
FORNER-CORDERO, A; ACKERMANN, M.; FREITAS, M. L. A Method to Simulate Motor
Control Strategies to Recover from Perturbations: Application to a Stumble Recovery
During Gait. Proc. of the 33rd Annual Intl IEEE EMBS Conf, 2011.
Bioinspired Mechanical Design of an Upper
Limb Exoskeleton for Rehabilitation
MIRANDA, A.B.W.; YASUTOMI, A.Y.; SOUIT, C.; FORNER-CORDERO, A . Bioinspired Mechanical
Design of an Upper Limb Exoskeleton for Rehabilitation and MotorControl Assessment.
BioRob2012. 4th IEEE RAS & EMBS International Conference on Biomedical Robotics and
Bioinspired elbow exoskeleton