Through studying these areas I have gained invaluable knowledge into how robots walk and the complexity of actually moving each leg and keeping the robot upright. In robotics a major stumbling point in design is how to maximise the time it takes for a robot to reposition itself after a stride has taken place. The duty factor as it is called is one of the areas I hope to improve on the robot. I have been looking a great deal into the size of the legs involved in the construction of the robot. I have read a lot of information on the internet and in journals, that have shown the advantages that an insect design has in robotics.
One of the main areas I have looked into this term is the effect of tractive effort. I want to be able to know what the forces acting on the leg of the robot as it moves. As there will be a vertical and a horizontal force associated with a step I want to know exactly what kind of range of forces are involved.. Therefore the test rig that I have designed is aimed at finding out the forces involved. The test rig is fully moveable , that is to say, that it can be moved up and down and side to side to see exactly what differences will be involved in a single stride of the robot. I have had to work out theoretically what the forces involved are and to then implement it to a working model. The way I am going to measure the forces is with a set-up of strain gauges, which I have also needed to work out which range of gauges are needed.
One of the other areas of my project I have investigated is the sensors that I will be attaching to the end of the leg on my test rig. I have looked at a great deal of different ideas that could be attached to the leg that will be on the test rig. I have looked at photoelectric sensors ( which are sensitive to light). Ultrasonics (which is the science of inaudible sounds ), but one of the better ideas is that of PVDF. This is a thin plastic sheet which gives out a short burst of current when it is put under pressure. This can be amplified through transducers and resistors so that a trace on an oscilloscope can be noted. This burst of current can then be used in the design to tell me when the leg has touched down on the surface I am testing. One problem arising is the burst only happens at contact and not through the entire process of the leg being in contact with the ground however as the leg moves off another burst is seen so there would be: Blip - gap - blip. As I want to know when the leg contacts the ground so that I can improve the duty factor so that I can make the leg push more when it is in transit.