scholarly journals The walking robots critical position of the kinematics or dynamic systems applied on the environment model

2018 ◽  
Vol 7 (2.28) ◽  
pp. 134
Author(s):  
Marcel Migdalovici ◽  
L Vladareanu ◽  
Hongnian Yu ◽  
N Pop ◽  
M Iliescu ◽  
...  

The exposure is dedicated in the first to mathematical modeling of the environment where the aspects on the walking robots evolution models are described. The environment’s mathematical model is defined through the models of kinematics or dynamic systems in the general case of systems that depend on parameters. The important property of the dynamic system evolution models that approach the phenomenon from the environment is property of separation between stable and unstable regions from the free parameters domain of the system. Some mathematical conditions that imply the separation of stable regions from the free parameters domain of the system are formulated.  In the second part is described our idea on walking robot kinematics and dynamic models with aspects exemplified on walking robot leg. An inverse method for identification of possible critical positions of the walking robot leg is established.  

Author(s):  
M. Migdalovici ◽  
L. Vladareanu ◽  
N. Pop ◽  
H. Yu ◽  
H. Yu ◽  
...  

The technological advancements at the global level have put in a large demand for walking robots in various industrial and domestic applications. The aim of the paper is to develop a Hexapod (robot with six legs) walking robot that is capable of performing basic movement, such as walking forward and backward, carry payloads and used as a surveillance device. A novel robot leg design has been created with Autodesk Fusion 360, linkage mechanisms of the robot leg is determined by using Linkage 2.0 software. Stress and displacement analysis was done in Autodesk fusion360 software in order to determine whether it can hold the self-weight of the robot and the desired payload to carry the surveillance purpose (i.e. medicine, water, blood etc.). Considering all the possibilities final optimized Hexapod robot design is created using Autodesk Fusion 360 software. Mainly, the undertaken design outline takes into account the fundamental features, such as basic structure, motion planning, payload and walking gait. Fabrication of Hexapod robot parts was completed using additive manufacturing technology FDM process.


Author(s):  
Yueh-Jaw Lin ◽  
Aaron Tegland

Abstract In recent years, walking robot research has become an important robotic research topic because walking robots possess mobility, as oppose to stationary robots. However, current walking robot research has only concentrated on even numbered legged robots. Walking robots with odd numbered legs are still lack of attention. This paper presents the study on an odd numbered legged (three-legged) walking robot — Tribot. The feasibility of three-legged walking is first investigated using computer simulation based on a scaled down tribot model. The computer display of motion simulation shows that a walking robot with three legs is feasible with a periodic gait. During the course of the feasibility study, the general design of the three-legged robot is also analyzed for various weights, weight distributions, and link lengths. In addition, the optimized design parameters and limitations are found for certain knee arrangements. These design considerations and feasibility study using computer display can serve as a general guideline for designing odd numbered legged robots.


Author(s):  
Peter V. Nagy ◽  
Subhas Desa ◽  
William L. Whittaker

Abstract A large number of walking robots walk with a statically-stable gait. A statically-stable walker has at least three feet that are in ground contact at any time. If there are more than three feet in ground contact, the normal (vertical) forces exerted by the ground on the feet of the walker are indeterminate, unless they are measured. Some walking robots may walk with more than three legs in ground contact in order to achieve greater stability. To ensure this stability it is desirable to predict how vertical forces passively redistribute underneath the feet during walker motions. Predictions of future foot forces can be used as a basis for accepting or rejecting any planned walker motion. Two methods — the least-squares method and the compliance method — for predicting this redistribution of forces in the face of static indeterminacy are presented in this work. Both methods are computationally efficient, and give reasonably accurate predictions, as verified by experiments on a walking robot.


Author(s):  
Sayat Ibrayev ◽  
Nutpulla Jamalov ◽  
Amandyk Tuleshov ◽  
Assylbek Jomartov ◽  
Aidos Ibrayev ◽  
...  

2010 ◽  
Vol 166-167 ◽  
pp. 297-302 ◽  
Author(s):  
Florina Moldovan ◽  
Valer Dolga

In this article is presented a short classification for walking robots that are based on leg locomotion and the main objectives that walking robots designers must achieve. The leg configuration of the walking robot is essential for obtaining a stable motion. Computer aided design process offers certain advantages for designers who attend to realize competitive products with fewer errors and in a short term. The aim of this article is to present the graphical results of the kinematic analysis of a new type of walking mechanism designed by Dutch physicist and sculptor Theo Jansen using Pro Engineer program and SAM, in order to compare the results.


Author(s):  
ChiHyo Kim ◽  
KunWoo Park ◽  
TaeSung Kim ◽  
MinKi Lee

This paper designs a four legged parallel mechanism to improve the dexterity of three layered parallel walking robot. Topology design is conducted for a leg mechanism composed of four legs, base and ground, which constitute a redundant parallel mechanism. This mechanism is subdivided into four sub-mechanism composed of three legs. A motor vector is adopted to determine the 6×8 Jacobian of the redundant parallel mechanism and the 6×6 Jacobian of the sub-mechanisms, respectively. The condition number of the Jacobian matrix is used as an index to measure a dexterity. We analyze the condition numbers of the Jacobian over the positional and orientational walking space. The analytical results show that a sub-mechanism has lots of singularities within workspace but they are removed by a redundant parallel mechanism improving the dexterity. This paper presents a parallel typed walking robot to enlarge walking space and stability region. Seven types of three layered walking robots are designed by inserting an intermediate mechanism between the upper and the lower legged parallel mechanisms. They provide various types of gaits to walk rough terrain and climb over a wall with small degrees of freedom.


2018 ◽  
Vol 7 (2.28) ◽  
pp. 123
Author(s):  
N Pop ◽  
L Vladareanu ◽  
H Wang ◽  
M Ungureanu ◽  
M Migdalovici ◽  
...  

Recovering and maintaining the balance of the biped walking robots play an important role in their operation. In this article we will analyze some strategies for balancing in the sagittal plane, in the presence of external disturbances and changing the proportions between leg’s length and trunk’s length (golden section), and/or adding weights (boot type) between the ankle and the knee so that the center of gravity is as low as possible. For equilibrium recovery, we suggest that the biped walking model be equipped with actuator that provides a torque at the hip. or/and at the ankle. The strategy of balance has a goal to move the disturbed system to the desired equilibrium state. We chose to study, the model of a double linear pendulum inverted under-actuated, with one passive and one active joint. Each case study and usage of these strategies is validated by Webots and is applied for NAO robot. 


2019 ◽  
Vol 16 (6) ◽  
pp. 172988141989132
Author(s):  
Ivan Chavdarov ◽  
Bozhidar Naydenov

The proposed study presents an original concept for the design of a walking robot with a minimum number of motors. The robot has a simple design and control system, successfully moves by walking, avoids or overcomes obstacles using only two independently controlled motors. Described are basic geometric and kinematic dependencies related to its movement. It is proposed optimization of basic dimensions of the robot in order to reduce energy losses when moving on flat terrain. Developed and produced is a 3-D printed prototype of the robot. Simulation and experiments for overcoming an obstacle are presented. Trajectories and instantaneous velocities centers of links from the robot are experimentally determined. The phases of walking and the stages of overcoming an obstacle are described. The theoretical and experimental results are compared. The suggested dimensional optimization approaches to reduce energy loss and experimental determination of the instant center of rotation are also applicable to other walking robots.


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