Near-Optimal Trajectory Generation of a Two-Legged Robot with Soft Sole on Staircase using PSO and ABC

2015 ◽  
Vol 3 (2) ◽  
pp. 1-19
Author(s):  
Naga Sudha Rani B ◽  
Vundavilli Pandu Ranga
Keyword(s):  
Dynamic Balance ◽  
Reaction Force ◽  
Biped Robot ◽  
Legged Robot ◽  
Walking Machine ◽  
Bee Colony ◽  
Zero Moment ◽  
Lumped Masses ◽  
Least Energy ◽  
Generation Problem

During biped locomotion the foot ground interaction plays an important role, as it takes the reaction force acting on the foot and allows stable walking of the biped robot. Generally, the foot is considered to be hard to solve the gait generation problem and dynamic balance aspects of the two-legged robot. However, a layer of rubber is placed on the sole of the robot to act as a shock absorber for all practical purposes. It is important to note that the soft sole gets deformed during walking of the robot and allows the limbs of the robot to bend that influences the dynamic balance of the walking machine. The aim of this study is to use two different non-traditional optimization algorithms, such as particle swarm optimization (PSO) and artificial bee colony (ABC) algorithms to obtain the optimal hip trajectory, damping coefficient and position of the lumped masses for a 7-DOF biped robot ascending the staircase. The dynamic balance of the gaits generated with soft sole is verified using the concept of zero moment point (ZMP). Further, the energy consumed in ascending the staircase with and without soft sole has been computed. The results of this study proved that, least energy is consumed with soft sole having correction for the deformation.

ONLINE DYNAMICALLY BALANCED ASCENDING AND DESCENDING GAIT GENERATIONS OF A BIPED ROBOT USING SOFT COMPUTING

2007 ◽  
Vol 04 (04) ◽  
pp. 777-814 ◽  
Author(s):  
PANDU RANGA VUNDAVILLI ◽  
SAMBIT KUMAR SAHU ◽  
DILIP KUMAR PRATIHAR
Keyword(s):  
Soft Computing ◽  
Large Scale ◽  
Fuzzy Logic Controller ◽  
Dynamic Balance ◽  
Biped Robot ◽  
Legged Robot ◽  
Gait Generation ◽  
Natural Choice ◽  
Rule Bases ◽  
Generation Problem

In the present paper, two algorithms based on soft computing have been developed for dynamically balanced gait generations of a biped robot ascending and descending a staircase. The utility of the soft computing tools is best justified, when the data available for the problem to be solved are imprecise in nature, difficult to model and exhibit large-scale solution spaces. The problem of online gait generation of a biped robot exhibits such a complex phenomenon, and ultimately soft computing has become a natural choice for solving it. The gait generation problems of a biped robot have been solved using two different approaches, namely genetic-neural (GA-NN) and genetic-fuzzy (GA-FLC) systems. In GA-NN, the gait generation problem of a two-legged robot has been modeled using two modules of Neural Network (NN), whose weights are optimized offline using a Genetic Algorithm (GA), whereas in GA-FLC, the above problem is modeled utilizing two modules of Fuzzy Logic Controller (FLC) and their rule bases are optimized offline using a GA. Once optimized, the GA-NN and GA-FLC systems will be able to generate dynamically balanced gaits of the biped robot online. The performances of the two approaches are compared with respect to the Dynamic Balance Margin (DBM).

DYNAMICALLY BALANCED ASCENDING AND DESCENDING GAITS OF A TWO-LEGGED ROBOT

2007 ◽  
Vol 04 (04) ◽  
pp. 717-751 ◽  
Author(s):  
PANDU RANGA VUNDAVILLI ◽  
SAMBIT KUMAR SAHU ◽  
DILIP KUMAR PRATIHAR
Keyword(s):  
Power Consumption ◽  
Inverse Method ◽  
Dynamic Balance ◽  
Average Power ◽  
Biped Robot ◽  
Motion Generation ◽  
Joint Torques ◽  
Trunk Motion ◽  
Average Power Consumption ◽  
Zero Moment

The present paper deals with dynamically balanced ascending and descending gait generations of a 7 DOF biped robot negotiating a staircase. During navigation, the foot of the swing leg is assumed to follow a trajectory, after ensuring its kinematic constraints. Dynamic balance margin of the gaits are calculated by using the concept of zero-moment point (ZMP). In the present work, an approach different from the well-known semi-inverse method has been developed for trunk motion generation, in which it is initially generated based on static balance and then checked for its dynamic balance. The joint torques are determined utilizing the Lagrange–Euler formulation, and the average power consumption at each joint is calculated. Moreover, variations of the dynamic balance margin are studied for both the ascending as well as descending gaits of the biped robot. Average dynamic balance margin and average power consumption in the ascending gait are found to be more than that of the descending gait. The effect of trunk mass on the dynamic balance margin and average power consumption for both the ascending and descending gaits are studied. The dynamic balance margin and average power consumption are found to decrease and increase, respectively with the increase in the trunk mass.

Switching Control Method for Stable Landing by Legged Robot Based on Zero Moment Point

2013 ◽  
Vol 25 (5) ◽  
pp. 831-839 ◽  
Author(s):  
Naoki Motoi ◽  
◽  
Kenta Sasahara ◽  
Atsuo Kawamura
Keyword(s):  
Control Method ◽  
Biped Robot ◽  
Switching Control ◽  
Contact Condition ◽  
Smooth Transition ◽  
Switching Function ◽  
Legged Robot ◽  
Position Controller ◽  
Zero Moment ◽  
The Moment

This paper proposes a switching control method to achieve a smooth transition from an edge landing to a sole landing for a legged robot. When a biped robot walks, an undesirable condition at the moment of landing, such as hunting between the ground and the foot, may occur for several reasons. To avoid this condition, this paper focuses on a method that uses simple controllers to ensure a smooth transition from an edge landing to a sole landing. In the event of an edge landing, a force controller should be implemented for a smooth transition to a sole landing. This is because the force controller enables the foot to contact the ground softly. After the landing state is shifted to the sole landing, the control method should be changed to the position controller. Therefore, it is necessary to switch the control method according to the contact condition between the foot and the ground. To avoid the chattering of the controller switching, several hysteresis values are used for the zeromoment point (ZMP) position and ZMP velocity in the switching function. Simulations and experimental results confirmed the validity of the proposed method.

ZMP: A REVIEW OF SOME BASIC MISUNDERSTANDINGS

2006 ◽  
Vol 03 (02) ◽  
pp. 153-175 ◽  
Author(s):  
MIOMIR VUKOBRATOVIĆ ◽  
BRANISLAV BOROVAC ◽  
VELJKO POTKONJAK
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Balance ◽  
Decisive Role ◽  
Humanoid Robots ◽  
Ground Contact ◽  
Science And Engineering ◽  
Theoretical Assumptions ◽  
Zero Moment ◽  
Basic Characteristics

One of basic characteristics of the regular bipedal walk of humanoid robots is the maintenance of their dynamic balance during the walk, whereby a decisive role is played by the unpowered degrees of freedom arising at the foot–ground contact. Hence, the role of the Zero-Moment Point (ZMP) as an indicator of dynamic balance is indispensable. This paper gives a detailed discussion of some basic theoretical assumptions related to the ZMP in the light of imprecise, and even incorrect, interpretations that have recently appeared, and which have led to some erroneous conclusions. Examples are given to show some erroneous basic attitudes and the genesis of some of them is indicated. It is also pointed out that in the domain of bipedal walk there are still notions that are not clearly defined and their meanings differentiated in some related branches of science and engineering. One of the examples is dynamic balance and stability, which are often used interchangeably.

Generating real-time trajectories for a planar biped robot crossing a wide ditch with landing uncertainties

Robotica ◽  
2018 ◽  
Vol 37 (1) ◽  
pp. 109-140 ◽  
Author(s):  
V. Janardhan ◽  
R. Prasanth Kumar
Keyword(s):  
Real Time ◽  
Degrees Of Freedom ◽  
Dynamic Balance ◽  
Surface Friction ◽  
Biped Robot ◽  
Net Energy ◽  
Leg Length ◽  
Uncertain Environments ◽  
Novel Concept ◽  
Time Planning

SUMMARYDitch crossing is one of the essential capabilities required for a biped robot in disaster management and search and rescue operations. Present work focuses on crossing a wide ditch with landing uncertainties by an under-actuated planar biped robot with five degrees of freedom. We consider a ditch as wide for a robot when the ankle to ankle stretch required to cross it is at least equal to the leg length of the robot. Since locomotion in uncertain environments requires real-time planning, in this paper, we present a new approach for generating real-time joint trajectories using control constraints not explicitly dependent on time, considering impact, dynamic balance, and friction. As part of the approach, we introduce a novel concept called the point of feasibility for bringing the biped robot to complete rest at the end of ditch crossing. We present a study on the influence of initial posture on landing impact and net energy consumption. Through simulations, we found the best initial postures to efficiently cross a wide ditch of width 1.05 m, with less impact and without singularities. Finally, we demonstrate the advantage of the proposed approach to cross a wide ditch when the surface friction is not same on both sides of the ditch.

scholarly journals Dynamic Walking of a Legged Robot in Underwater Environments

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3588 ◽  
Author(s):  
Portilla ◽  
Saltarén ◽  
Espinosa ◽  
Barroso ◽  
Cely ◽  
...  
Keyword(s):  
Legged Robot ◽  
Dynamic Walking ◽  
Zero Moment Point ◽  
Hydraulic Actuators ◽  
External Perturbations ◽  
Underwater Environment ◽  
Zero Moment

In this research, the dynamic walking of a legged robot in underwater environments is proposed. For this goal, the underwater zero moment point (Uzmp) is proposed in order to generate the trajectory of the centre of the mass of the robot. Also, the underwater zero moment point auxiliary (Uzmp aux.) is employed to stabilize the balance of the robot before it undergoes any external perturbations. The concept demonstration of a legged robot with hydraulic actuators is developed. Moreover, the control that was used is described and the hydrodynamic variables of the robot are determined. The results demonstrate the validity of the concepts that are proposed in this article, and the dynamic walking of the legged robot in an underwater environment is successfully demonstrated.

A force-resisting balance control strategy for a walking biped robot under an unknown, continuous force

Robotica ◽  
2014 ◽  
Vol 34 (7) ◽  
pp. 1495-1516
Author(s):  
Yeoun-Jae Kim ◽  
Joon-Yong Lee ◽  
Ju-Jang Lee
Keyword(s):  
External Force ◽  
Control Strategy ◽  
Balance Control ◽  
Biped Robot ◽  
Second Step ◽  
Double Support ◽  
Zero Moment ◽  
External Forces ◽  
Single Support Phase ◽  
Support Phase

SUMMARYIn this paper, we propose and examine a force-resisting balance control strategy for a walking biped robot under the application of a sudden unknown, continuous force. We assume that the external force is acting on the pelvis of a walking biped robot and that the external force in the z-direction is negligible compared to the external forces in the x- and y-directions. The main control strategy involves moving the zero moment point (ZMP) of the walking robot to the center of the robot's sole resisting the externally applied force. This strategy is divided into three steps. The first step is to detect an abnormal situation in which an unknown continuous force is applied by examining the position of the ZMP. The second step is to move the ZMP of the robot to the center of the sole resisting the external force. The third step is to have the biped robot convert from single support phase (SSP) to double support phase (DSP) for an increased force-resisting capability. Computer simulations and experiments of the proposed methods are performed to benchmark the suggested control strategy.

scholarly journals The Effect of Teeth Clenching on Dynamic Balance at Jump-Landing: A Pilot Study

2017 ◽  
Vol 33 (3) ◽  
pp. 211-215
Author(s):  
Tomomasa Nakamura ◽  
Yuriko Yoshida ◽  
Hiroshi Churei ◽  
Junya Aizawa ◽  
Kenji Hirohata ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Masseter Muscle ◽  
Center Of Pressure ◽  
Dynamic Balance ◽  
Reaction Force ◽  
Force Plate ◽  
Vertical Ground Reaction Force ◽  
Jump Landing ◽  
Teeth Clenching ◽  
Vertical Ground

The aim of this study was to analyze the effect of teeth clenching on dynamic balance at jump landing. Twenty-five healthy subjects performed jump-landing tasks with or without teeth clenching. The first 3 trials were performed with no instruction; subsequently, subjects were ordered to clench at the time of landing in the following 3 trials. We collected the data of masseter muscle activity by electromyogram, the maximum vertical ground reaction force (vGRFmax) and center of pressure (CoP) parameters by force plate during jump-landing. According to the clenching status of control jump-landing, all participants were categorized into a spontaneous clenching group and no clenching group, and the CoP data were compared. The masseter muscle activity was correlated with vGRFmax during anterior jump-landing, while it was not correlated with CoP. In comparisons between the spontaneous clenching and the no clenching group during anterior jump-landing, the spontaneous clenching group showed harder landing and the CoP area became larger than the no clenching group. There were no significant differences between pre- and postintervention in both spontaneous clenching and no clenching groups. The effect of teeth clenching on dynamic balance during jump-landing was limited.

Sign in / Sign up

Export Citation Format

Share Document