ArtBot

ODOI Artistic Design

I did not post since I finished the first version of the robot in January. It is because I am focusing on the gait algorithm – with the goal to release a video in June - as well as debugging the mechanical part of the robot.

I will post a note on the things I am learning – to share my experience with other robot makers. For instance all the frames are made of Resin and I noticed that some frames were bending, stressed by mechanical efforts – especially at the hip. So I had to reinforce them with brackets in Aluminum.  It is quite a frustrating period because I need to understand how the structure of the robot is working in the real world and how to deal with “unexpected” (I did not think about them before) issues. Although it is frustrating it is also a necessary (sometimes exciting) learning period.

In this note, I want to talk about Design. I think that Artistic Design is really very important:

• To introduce robots in the human environment that can be accepted and/or tolerated by the population;
• To make them appealing so that somebody is considering purchase one of them.

Robot finally assembled

After months of hard working, the robot is finally assembled. It is 65cm tall and here are some pics of the whole robot and details about the torso, the foot and the back.

Lower part of the body assembled and tested - new design of the foot

I finished to built the lower part of the body of the robot. Here are some pictures of how it looks like with a focus on the foot and the silicon layer under the foot.

Lower part of the body almost done

These days I am building the robot. Most of the frames have been created by a 3D printer, namely the FORM 1+, which really fantastic. If I have enough time I will write a note about it.

Software architecture overview

In this document, we will provide a brief overview of the software architecture developed to generate and run ODOI gaits.

We focus on Gait simulation and execution only. Another step will be the description of the software that will be able to trigger specific behaviors based on sensory inputs.

The objective is to generate, test and validate a set of “standard” robot gaits and to observe, by changing the stride length for instance, if we can notice some “patterns”.

Human gait cycle : importance of the stride length

So far we did not speak about the stride length, which is defined as the distance between two successive placements of the same foot, but it is the parameter that will determine whether the gait is slow, medium or fast.

In our study we will consider that stride length will be determine by the following parameters:

• Rotation of the pelvic in the Horizontal plane ;
• Thigh/Hip flexion in the Sagittal plane;

Human gait cycle : some graphs

Here are some graphics in the different planes in order to illustrate what have been discussed in the note “A study of the human gait cycle in order to design a biped robot”.

 

Description of the ODOI platform : mechanical part

In this note, we will overview the main features of the ODOI platform. Finally I completed the whole design and one can see below how it looks like.

A study of the human gait cycle in order to design a biped robot

To make a biped walking machine, it seems to me essential to understand as we walk. This is precisely the aim of the study. It differs from other studies because the pelvis and chest (pectoral girdle and arm) are taken into account.

1      Take a closer look at human gait

1.1    Introduction

Biomechanics defines walking a form of bipedal locomotion as there is an alternating action between lower extremities. One leg is in touch with the ground for restraining, supporting and propulsion.

The other leg is in swing phase for creating a new step forward. So gait is the result of a series of rhythmic alternating movement of arms, legs, and trunk which create forward movement of the body.

By convention, the gait cycle begins with the initial placement off the right heel and ends when the same heel contacts the ground.

La marche c'est aussi raconter une histoire

Quand on observe déambuler quelqu’un dans la rue, nous avons souvent de nombreuses images qui nous viennent, cette personne est-elle heureuse /malheureuse, riche/pauvre, exerce une profession manuelle/intellectuelle, jeune/moins jeune/vieille, agréable/acariâtre … car quand on marche, l’ensemble du corps raconte une histoire.

Pour le démontrer on va s’inspirer des animateurs. Ceux sont d’excellents observateurs dont l’une des tâches est d’exagérer certaine expressions des caractères qu’ils animent dans le but justement de susciter une réaction.

Dans le cadre de ce travail, nous sommes exactement dans la même perspective. Ce qui nous différencie des animateurs, c’est la réalité.  Les animateurs ne sont pas soumis aux lois de la physique, ils en jouent même souvent pour créer des situations qui nous feront rire en général.