Biomechancal analysis of rising to standing from sitting

BIOMECHANICAL ANALYSIS

Sit to stand movement is one of the most important human activities.

1. Sit to stand Analysis
We can divide this movement in three phases. Each phase is differentiated in terms of momentum and stability characteristics.

Phase 1: Inititation or Acceleration phase

In this phase, the center of gravity is accelerated onto the horizontal direction until to acquire its maximum speed, Some scientist also call it, acceleration phase.

Is a flexion-momentum phase used to generate the initial momentum for rising.

Phase 2 or Transition phase.

This phase begins when the center of gravity is in its maximal horizontal speed, and ends when CG reachs its maximal vertical speed.

Begins as the individual leaves the chair seat and ends at maximal ankle dorsiflexion. Forward momentum of the upper body is transferred to forward and upward momentum of the total body.

Phase 3 or Descceleration or Stabilitation phase

It begins when CoG is on its maximal speed and the full body begins to elevate itself, moving vertically its center of gravity until to stabilize its base of sustentation rising its full upright position. As speed is decreasing in this phase, it's also normally called desacceleration phase.

2 Muscles actions at standing

The extensor muscles that support erect posture are called posturals or antigravitatores. Theses muscles have red fibers that are highly resistent to fatigue, Its energy comsumption is low and show a kind of contractions that's called tonic contraction.

3 Antigravitatories muscles at erect posture

· Neck Extensor muscles
· Erector spinae muscles
· Gluteal muscles
· Quadriceps muscles.
· Tríceps sureal muscle (gemellus y soleus).

XQ PROJECT

1. INTRODUCTION

One of the newest important research trends in these days about robotics is, without a doubt, Biomechatronics. This line is about robotics applications into the medicine, In fact, there are lots of Universities around the world developing projects in this area.

Well, from my point of view, two mains areas are oriented to, #Exoskeletots and #BCI's.. Currently, people around the world search the best way to build the most efficiently, robust, and economic prototype of exoskeleton, and, on the other hand, the advances onto Brain Computer Interfaces' performance are really amazing... and getting better.

Asia is, I'm pretty sure, the continent with more amazing advances in Exoskeletons, however, Europe and United States are getting really interesting results in BCI's.

In SouthAmérica, Brasil is who is investing more resources in these lines of research, and Colombia and Argentina, the next ones.

In Perú, there is no yet a strongh orientation to this area, however, there are isolated cases as PUCP, UNI, UNT and UdeP, who have begun some year before to develop interesting projects presented in national Congress and some Internationals.

Well, the aim of this project was born under the necessity of people who have pathologies of muscle weakness in their lower limbs, so, it's due as for neurological problems as for rehabilitation process after a traumatism or post operatory

This design search to cooperate with the lower limb movement rehabilitation process of the user/patient

Electromyography analysis and signal processing are essential parts of this project, so, we will be able to identify the movement that the patient/user wants to do.

Kinematics and dynamics analysis are been made powered by SimMechanics from Matlab and Solid Works

The controller is a PID with gravity compensation, It's a old algorithm, but is always efficient.

Furthermore, the Exoskeleton is able to use in some industrial aplications as packaging, building industry, mechanic maintenance, etc. Definitely, there is a world of applications related to human gait improvements.