Technology has beenadvanced from swords to bows and arrows through the discovery of riffles andthe invention of the aircraft and now to the presence of unmanned laser guidedaerial drones and various robots. The military is now hoping for the new classof warrior –Exoskeleton envisions dreams to come into reality and procreates adismounted soldiers into a faster robust and empowered exoskeleton suits suchas “iron man”. Exoskeletons are external skeleton structuresthat are used to protect animal’s body.
Military Exoskeletons orexo-suits have been in development since early 1960’s, often known as wearablerobotics for military designed to boost soldier’s strength and endurance. Theseare devices which is put on a human and is intended for humans’ augmentation inparticular to increase the efforts that a person may apply .They help soldiersto carry heavy loads both in and out of combat, run at faster speeds and defendthemselves from enemy attacks. These systems are anthromorphic (ascribing humancharacteristics to nonhuman things) devices that work in conjunction with our body’snatural architecture. There are several factors driving the demand for theseexoskeletons globally. The most basicexoskeleton is more or less a pair of legs taking the weight of an equipmentrack .Current programmer’s,such as Raytheon’s XOS exoskeleton and Lockheed Martin’s human universal loadcarrier (HULC) have demonstrated greatly improved strength, allowing soldier tocarry loads of up to 200lbs for extended periods of time. They arehydraulic-powered, anthropomorphic exoskeleton designed specifically to fitaround the body of a dismounted soldier.
There is no control mechanism, instead sensors detectmovement and, using an micro-computer, make the suit to move in time with thebody. The system’s titanium structure and hydraulic power augments thesoldier’s ability, strength and performance, whereas its modularity allowscomponents to be switched and replaced with ease.One big problem was that theseinitial exoskeletons forced wearers to walk in an unfamiliar way.Thatdifficulty was compounded by a lack of coordination between human and machine. Further inventions involved in eliminating themain reason of former failures through the uses of different approaches. Latestexoskeletons has been developed to reduce the weight that impact on the wearerand also various exo-frames were introduced in both military and medical fieldsfor rehabilitation purposes such as restoring lost limb functions. OurExoskeleton is specifically designed for soldiers and acts as a coalescence oftechnologies.
We have proposed aexoskeleton which helps to carry load without causing an effect for wearer.Former powered exoskeletons uses some mechanical movement as a single powersource and batteries or fuel cells as power storage which acted as a mainreason for weight of the exoskeleton. Our exo suit consists of distributedpower sources of three types (1)power generated from backpack.(2)powergenerated from the wearers knee and (3) power generated from the wearers shoe.These sources produce power enough to allow the exoskeleton produce the wearerstrength and endurance to move along with a load of approximated weight. Linearactuators have been used to create more compact design with bettercharacteristics. BACKPACK POWER GENERATOR The linkages were attached to the back frame andwere located on either side of the body.
They acted as a first class lever withthe pivot at the centre. The load and the actuating force wereon either ends ofthe link. The lengths of the links and the forces acting on them can becalculated.The law of moments was applied to obtain the force that the actuatormust provide in order to lift the weight.
The back frame consists of two vertical structureswith two cross links in order to set them apart. L links projecting backwardswere used to attach the actuator.They were welded to the back frame.
Theactuators were fixed rigidly at the end to the back frame. Hence the stressinduced in the L link and the strength of the welds must to bedetermined. The material used was cold rolled steel. The axial stress,maximum normal stress were calculated for each link and they were within theyield strength of the material chosen.
As shown in the figure a load isattached to a load plate which is placed on the L links. Due to the walkingmovement of the wearer, a force is applied on the linear actuators placed onthe hip section which makes the spring attached to the back frame move whichinstead provides vertical movement to the load plate. This in turn generate powerwhich is stored in the battery situated beneath the L linkages. The powerstored in the battery used by the exoskeleton for the mechanical movements.
