scholarly journals Walking Without Impacts as a Motion/Force Control Problem

1992 ◽  
Vol 114 (4) ◽  
pp. 660-665 ◽  
Author(s):  
W. Blajer ◽  
W. Schiehlen
Keyword(s):  
Control Problem ◽  
Force Control ◽  
Numerical Results ◽  
Bipedal Walking ◽  
Motion Simulation ◽  
Bipedal Robot ◽  
Combined Motion ◽  
Ground Reactions

The paper deals with the synthesis of control for impactless bipedal walking. In order to avoid impacts, both the specified motion of the biped and its ground reactions are controlled, yielding a combined motion and force control problem. A method for modeling and solving such problems is proposed, and then illustrated by the example of an impactless planar walk of a seven-link bipedal robot. Some numerical results of the motion simulation are reported.

Very Large Eddy Simulation of Passive Drag Control for a D-Shaped Cylinder

2013 ◽  
Vol 135 (10) ◽  
Author(s):  
Xingsi Han ◽  
Siniša Krajnović
Keyword(s):  
Large Eddy Simulation ◽  
Flow Control ◽  
Control Problem ◽  
Bluff Body ◽  
Numerical Study ◽  
Numerical Results ◽  
Complex Flow ◽  
Local Disturbance ◽  
Eddy Simulation ◽  
Large Eddy

The numerical study reported here deals with the passive flow control around a two-dimensional D-shaped bluff body at a Reynolds number of Re=3.6×104. A small circular control cylinder located in the near wake behind the main bluff body is employed as a local disturbance of the shear layer and the wake. 3D simulations are carried out using a newly developed very large eddy simulation (VLES) method, based on the standard k − ε turbulence model. The aim of this study is to validate the performance of this method for the complex flow control problem. Numerical results are compared with available experimental data, including global flow parameters and velocity profiles. Good agreements are observed. Numerical results suggest that the bubble recirculation length is increased by about 36% by the local disturbance of the small cylinder, which compares well to the experimental observations in which the length is increased by about 38%. A drag reduction of about 18% is observed in the VLES simulation, which is quite close to the experimental value of 17.5%. It is found that the VLES method is able to predict the flow control problem quite well.

scholarly journals A Dai–Yuan conjugate gradient algorithm of linear equation constrained optimization approach for optimal robust controller of bipedal robots

2020 ◽  
Vol 17 (1) ◽  
pp. 172988141989017
Author(s):  
M Wang ◽  
ZB Sun ◽  
BC Zhang ◽  
ZX Pang ◽  
DW Jiang
Keyword(s):  
Robust Control ◽  
Constrained Optimization ◽  
Linear Equation ◽  
Hybrid System ◽  
Optimization Problem ◽  
Numerical Results ◽  
Control Technique ◽  
Bipedal Robots ◽  
Robust Controller ◽  
Bipedal Robot

In this article, combined rapidly exponential control Lyapunov function with hybrid zero dynamics, a sufficiently descent projected Dai–Yuan approach is proposed, investigated, and analyzed for online solving optimal robust control problems with linear equation constraints of bipedal robots. Moreover, a new approach is developed for designing optimal robust controller. To demonstrate the effectiveness and feasibility of the proposed method, we will conduct numerical simulations on the model of three-link robot with nonlinear, impulsive, and under-actuated dynamics. Numerical results show that the bipedal robot can walk effectively and stability on the ground though the optimal robust controller when the parameters of the hybrid system model are disturbed three times. Furthermore, under the random noise condition, the bipedal robot can walk stably and effectively through online computing the nonlinear optimization problem for optimal robust controller. In addition, some classical control methods are compared with the developed approach in this article, numerical results are reported and analyzed to substantiate the feasibility and superiority of the proposed method for linear equation constrained optimization problem. Last, this article develops a systematic approach on exploiting optimal robust control technique to design hybrid system models for robustly and accurately via online solving linear equation constrained optimization problems.

YAW MOMENT COMPENSATION FOR BIPEDAL ROBOTS VIA INTRINSIC ANGULAR MOMENTUM CONSTRAINT

2012 ◽  
Vol 09 (04) ◽  
pp. 1250033 ◽  
Author(s):  
BARKAN UGURLU ◽  
JODY A. SAGLIA ◽  
NIKOS G. TSAGARAKIS ◽  
DARWIN G. CALDWELL
Keyword(s):  
Angular Momentum ◽  
Bipedal Walking ◽  
Upper Body ◽  
Rotational Inertia ◽  
Bipedal Robots ◽  
Bipedal Robot ◽  
Crucial Component ◽  
Intrinsic Angular Momentum ◽  
Momentum Constraint ◽  
Yaw Moment

This paper is aimed at describing a technique to compensate undesired yaw moment, which is inevitably induced about the support foot during single support phases while a bipedal robot is in motion. The main strategy in this method is to rotate the upper body in a way to exert a secondary moment that counteracts to the factors which create the undesired moment. In order to compute the yaw moment by considering all the factors, we utilized Eulerian ZMP Resolution, as it is capable of characterizing the robot's rotational inertia, a crucial component of its dynamics. In doing so, intrinsic angular momentum rate changes are smoothly included in yaw moment equations. Applying the proposed technique, we conducted several bipedal walking experiments using the actual bipedal robot CoMan. As the result, we obtained 61% decrease in undesired yaw moment and 82% regulation in yaw-axis deviation, which satisfactorily verify the efficiency of the proposed approach, in comparison to off-the-shelf techniques.

Ant Colony Optimization for Optimal Control in Manufacturing Engineering

2013 ◽  
Vol 340 ◽  
pp. 273-276
Author(s):  
Jie Bai ◽  
Li Zu ◽  
Wei Liu
Keyword(s):  
Optimal Control ◽  
Optimal Control Problem ◽  
Control Problem ◽  
Ant Colony Optimization ◽  
Heuristic Algorithm ◽  
Numerical Results ◽  
Ant Colony ◽  
Control Input ◽  
Algorithm Optimization ◽  
And Control

A meta-heuristic algorithm optimization, Ant Colony Optimization, is used to solve a general optimal control problem. Ant Colony Optimization is introduced briefly in this paper. The disc resection of the control time and control input is investigated. A piece wise interval is considered in the converting. And the simulation in numerical results show this strategy is feasible and effective.

Design and Control of the Planar Bipedal Robot ERNIE

2007 ◽  
Author(s):  
T. Yang ◽  
E. R. Westervelt ◽  
J. P. Schmiedeler ◽  
R. A. Bockbrader
Keyword(s):  
Sagittal Plane ◽  
Control Strategies ◽  
Frontal Plane ◽  
High Gain ◽  
Bipedal Walking ◽  
Knee Joints ◽  
Confined Space ◽  
Bipedal Robot ◽  
Hybrid Zero Dynamics ◽  
And Control

This paper presents the development of the planar bipedal robot ERNIE. ERNIE has 5 links: a torso, two femurs and two tibias without feet. ERNIE was designed and constructed to serve as a testbed for the development of novel control strategies for bipedal walking. A boom provides frontal plane stability, restricting walking motions to the sagittal plane, and ERNIE is configured to walk on a treadmill so that it can walk indefinitely in a confined space. ERNIE’s legs are modular so that morphological asymmetries and the use of feet may be explored more in future studies. Springs can be attached across the knee joints in parallel with the knee actuators to enable gaits that are more energetically efficient. ERNIE is currently controlled using the hybrid zero dynamics framework in which a function of the robot’s configuration that monotonically increases over a step is used to parameterize holonomic constraints on the robot’s motion. The constraints are designed via parameter optimization to minimize an objective function, such as the energy consumed over a step, and, at the same time, ensure gait stability. The constraints are enforced using decoupled high-gain PD control.

Study of Symmetric Solutions of an Underactuated Bipedal Robot

2018 ◽  
Author(s):  
Prachi Shah ◽  
Vivek Sangwan
Keyword(s):  
Energy Efficiency ◽  
Walking Speed ◽  
Solution Space ◽  
Bipedal Walking ◽  
Walking Robot ◽  
Bipedal Robot ◽  
The Past ◽  
The Family ◽  
Two Parameter ◽  
Selection Of

Underactuated bipedal walking has been intensively studied for the past few decades and several methods have been proposed to design trajectories; however, quickly generating trajectories with varying speeds remains a challenge. One solution is to have a library of trajectories precomputed from which a new one can be picked or constructed quickly based on specific requirements. For this to become feasible one needs to develop a good understanding of the solution space. This is non-trivial for a non-linear hybrid system such as a walking robot. The goal of this study is to explore a two parameter solution space of simple underactuated biped, under a specific virtual constraint, used in literature, to enforce a symmetric gait. The family of feasible walking solutions identified is further evaluated for performance and energy efficiency. This analysis can potentially facilitate quick selection of walking trajectories for meeting specific walking speed and efficiency requirements.

scholarly journals Simulation and Experimental Walking Pattern Generation for Two Types of Degrees of Freedom Bipedal Locomotion Robot

2020 ◽  
Vol 26 (12) ◽  
pp. 1-20
Author(s):  
Ali Fawzi Abdul Kareem ◽  
Ahmed Abdul Hussein Ali
Keyword(s):  
Degrees Of Freedom ◽  
Pattern Generation ◽  
Driver Model ◽  
Bipedal Walking ◽  
Time Interval ◽  
Bipedal Robot ◽  
Walking Pattern ◽  
Walking Pattern Generation ◽  
Arduino Microcontroller ◽  
Support Phase

Humanoids or bipedal robots are other kinds of robots that have legs. The balance of humanoids is the general problem in these types when the other in the support phase and the leg in the swing phase. In this work, the walking pattern generation is studied by MATLAB for two types of degrees of freedom, 10 and 17 degrees of freedom. Besides, the KHR-2HV simulation model is used to simulate the experimental results by Webots. Similarly, Arduino and LOBOT LSC microcontrollers are used to program the bipedal robot. After the several methods for programming the bipedal robot by Arduino microcontroller, LOBOT LSC-32 driver model is the better than PCA 96685 Driver-16 channel servo driver for programming the bipedal walking robot. The results showed that this driver confirms the faster response than the Arduino microcontroller in walking the bipedal robot. The walking pattern generation results showed that the step height for 17 degrees of freedom bipedal robot increases approximately (20%) than 10 degrees of freedom bipedal robot, which decreases the step period by about (7%). Also, the time interval of the double support phase for 17 degrees of freedom bipedal robot increases approximately (11%) with decreases step length approximately (33% on X-axis) and (16% on Z-axis).  

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