Optimal Reference Motions With Rotation of the Feet for a Biped

2008 ◽  
Author(s):  
D. Tlalolini ◽  
C. Chevallereau ◽  
Y. Aoustin
Keyword(s):  
Biped Robot ◽  
Humanoid Robots ◽  
Optimization Process ◽  
Human Walking ◽  
Flat Foot ◽  
Double Support ◽  
Rotation Phase ◽  
Support Phase ◽  
Fast Motions ◽  
Double Support Phase

Fast human walking includes a phase where the stance heel rises from the ground and the stance foot rotates about the stance toe. This phase where the biped becomes under-actuated is not present during the walk of humanoid robots. The objective of this study is to determine if the introduction of this phase for a biped robot is useful to reduce the energy consumed in the walking. For simplicity only a planar biped is considered. In order to study the efficiency of this phase, four cyclic gaits are presented. For these gaits optimal motions with respect to the torque cost are defined for given performances of actuators. It is shown that for fast motions a foot rotation sub-phase is useful to reduce the criteria cost. In the optimization process, under-actuated phase (foot rotation phase), fully-actuated phase (flat foot phase) and over-actuated phase (double support phase) are considered.

Development of multi-phase dynamic equations for a seven-link biped robot with improved foot rotation in the double support phase

2014 ◽  
Vol 229 (1) ◽  
pp. 3-17 ◽  
Author(s):  
Farsam Farzadpour ◽  
Mohammad Danesh ◽  
Seyed M TorkLarki
Keyword(s):  
Power Consumption ◽  
Trajectory Generation ◽  
Biped Robot ◽  
Dynamic Equations ◽  
Total Power ◽  
Phase Dynamic ◽  
Double Support ◽  
Multi Phase ◽  
Support Phase ◽  
Double Support Phase

Gait generation plays a significant role in the quality of locomotion of legged robots. This paper presents the development of multi-phase dynamic equations and optimal trajectory generation for a seven-link planar-biped robot walking on the ground level with consideration of feet rotation in the double support phase. The main contribution of this paper is to increase the stability margin at the phase transition time for simultaneous feet rotation in double support phase by introducing a new style of feet rotation. First, the derivation of the dynamics equations, which is a challenging problem due to the existence of the holonomic constraints, is performed using the Lagrangian formulation. Then, an analytical solution to inverse kinematics is proposed to determine the angles of each joint. A multi-objective genetic algorithm-based optimization technique is proposed to obtain the key parameters in trajectory generation so that the zero moment point tracks a predefined stable trajectory and additionally minimizes the power consumption, which is subjected to actuators’ powers limitations. The effect of the hip height on the total power consumption is also investigated. The numerical simulations demonstrate the effectiveness of the proposed method.

GA Based Trajectory Generation for a 7-DOF Biped Robot by Considering Feet Rotation during Double Support Phase

2012 ◽  
Vol 463-464 ◽  
pp. 1252-1255 ◽  
Author(s):  
Farsam Farzadpour ◽  
Mohammad Danesh
Keyword(s):  
High Speed ◽  
Trajectory Generation ◽  
Biped Robot ◽  
Bipedal Walking ◽  
Double Support ◽  
Straight Line ◽  
Zero Moment ◽  
The Stability ◽  
Support Phase ◽  
Double Support Phase

This paper presents a trajectory generation approach for a 7-DOF biped robot on level ground. Simultaneously rotation of feet in double support phase is considered which leads to high-speed and more similar to human being walking. The zero moment point (ZMP) stability criterion is used to ensure the stability of the bipedal walking robot. Since ZMP trajectory in human walking does not stay fixed, it needs to be a straight line shaped forward ZMP trajectory to have a natural walk. A genetic algorithm based method is proposed to obtain key parameters in trajectory generation such that the ZMP follows a predefined trajectory while minimizing power consumption. Simulation results demonstrate the effectiveness of the proposed method.

scholarly journals Effects of Torso Pitch Motion on Energy Efficiency of Biped Robot Walking

2021 ◽  
Vol 11 (5) ◽  
pp. 2342
Author(s):  
Long Li ◽  
Zhongqu Xie ◽  
Xiang Luo ◽  
Juanjuan Li
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Biped Robot ◽  
Gait Pattern ◽  
Pattern Generation ◽  
Biped Robots ◽  
Pitch Motion ◽  
Double Support ◽  
Gait Parameters ◽  
Support Phase

Gait pattern generation has an important influence on the walking quality of biped robots. In most gait pattern generation methods, it is usually assumed that the torso keeps vertical during walking. It is very intuitive and simple. However, it may not be the most efficient. In this paper, we propose a gait pattern with torso pitch motion (TPM) during walking. We also present a gait pattern with torso keeping vertical (TKV) to study the effects of TPM on energy efficiency of biped robots. We define the cyclic gait of a five-link biped robot with several gait parameters. The gait parameters are determined by optimization. The optimization criterion is chosen to minimize the energy consumption per unit distance of the biped robot. Under this criterion, the optimal gait performances of TPM and TKV are compared over different step lengths and different gait periods. It is observed that (1) TPM saves more than 12% energy on average compared with TKV, and the main factor of energy-saving in TPM is the reduction of energy consumption of the swing knee in the double support phase and (2) the overall trend of torso motion is leaning forward in double support phase and leaning backward in single support phase, and the amplitude of the torso pitch motion increases as gait period or step length increases.

Effect of Heel to Toe Walking on Time Optimal Walking of a Biped During Single Support Phase

2014 ◽  
Author(s):  
Tara Farizeh ◽  
Mohammad Jafar Sadigh
Keyword(s):  
Whole Body ◽  
Maximum Speed ◽  
Flat Foot ◽  
Double Support ◽  
Time Optimal ◽  
Foot Model ◽  
Two Phases ◽  
Single Support Phase ◽  
Toe Walking ◽  
Support Phase

Dynamic modeling of a biped has gained lots of attention during past few decades. While stability and energy consumption were among the first issues which were considered by researchers, nowadays achieving maximum speed and improving pattern of motion to reach that speed are the important targets in this field. Walking model of bipeds usually includes two phases, single support phase (SSP), in which only the stance foot is in contact with the ground while the opposite leg is swinging; and double support phase (DSP) in which the swing leg is in contact with the ground in addition to the rear foot. It is common in the simplified model of walking to assume the stance leg foot, flat during the entire SSP; but one may know that for human walking, there is also a sub-phase during SSP in which the heel of stance foot leaves the ground while the whole body is supported by toe link. Actually in this sub phase the stance leg foot rotates around the toe joint. This paper is trying to study the effect of toe-link and heel to toe walking model on dynamic and specially speed of walking compare to flat foot model.

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