Neck movement operated wheel chair for People affected with Quadriplegia.

The crux of our paper is to design a feasible method for the locomotion of the people

affected by the disease called QUADRIPLEGIA. The field, robotics has drawn our mutual interest

and it is because of this field we were both able to think of such an idea. Within this enormous

subject there is a classification of robots which are known as autonomous robots. These are

machines which are capable of performing the task without any human intervention. The whole

system here has a brain of its own and it can take particular feed back from the environment and

act according to the circumstances. This kind of an efficient closed loop feedback system is pretty

difficult to fabricate, the errors involved are numerous. However, with a little knowledge from a

workshop in the IIT(Bombay) we were able to think of a prototype and work on it as of now. The

wheelchair we are proposing is almost autonomous. It just requires a mere bend of the neck form

the affected patient in order to activate and perform the task according to the signals generated

by the accelerometer which is the major component of this wheelchair, the fact that an

accelerometer can be used as a sensor which has the capability to measure and generate signals

according to the tilt it is given is considered in this paper. Quadriplegia is a condition in which the

victims have lost sensation and mobility in their both lower and upper parts of the body. As it

affects all the four extremities, this condition can also be called as TETRAPLEGIA. The

accelerometer used is AS7260KB31003. It is fixed in the neck of the quadriplegia patient. The

angle of the neck movement is measured and transmitted to the microcontroller. The

microcontroller has an inbuilt ADC which converts the analog output voltage of the accelerator to

digital signal. For every angle, the microcontroller is programmed to perform certain specific

operations. The DC motor is fixed to the wheel chair. Based on the signal from the microcontroller,

the wheel chair moves in four directions namely, forward, reverse, left, right. An IR sensor is also

fixed to the wheel chair in order to avoid accidents with the obstacles it meets in its way during

locomotion.

The photos shown are the photos of the mother board, the main sensor(accelerometer) and the complete prototype.

By,
Harini Sekar & Kunal Bajaj

Hot-SPOT robotics!!!

Wondering what I am talking about?? well, the topic for discussion is resistance spot welding which is used by many aeronautic and automobile industries as one of the major processes for joining workpieces(metal of course!)... There have been proposals of a lot of ideas for welding and the joining of sheet metals but resistance spot welding by far remains the most cost effective and efficient among them.

In the current time period it has become common to use welding guns which are driven by a servo motor since their performance and output quality are a hell lot better than their predecessors the pneumatically driven welding guns. The accurate control of the servo motors position and torque is what makes these guns a lot more easy to use in the field of work. The position and velocity of the welding guns are determined by the frequency of the pulses which are being sent to the servo motor.

In addition to all these advantages the welding time cycle is reduced when the electric servo is used instead of the pneumatically driven welding guns. The time saved would be less relatively when compared with the pneumatically driven mechanism but when it comes to welding a huge number of spots in a car or another work object then the time saved is tremendous!! Just multiply the time with the number of spots you need to weld you will be amazed.. lets say the time saved is 0.4 seconds for a spot and there are thousands of spots in an automobile, I think you will now get my drift.. As we all know life is always equally balanced if there is something positive about something there has to be a negative!! Nobody is perfect you know!!.. So, the servo mechanism has its own disadvantages, the output force accuracy of the servo gun may be higher than that of the pneumatic gun but it is affected by certain factors like temperature, wear and tear, stiffness etc... I hope this was quite informative .. try going through the block diagrams to get a clear idea of what I was talking about...

By,
Kunal.K.Bajaj & S.Karthik Priyadarshan