The biomechanics of a grasshopper or locust's legs is fascinating, so we builtt a quick and dirty prop we built for a one off live show for the Naked Scientists
Looked up how Crickets and Grasshopper, jump so high first vid is a New York times video titled "Crickets can jump 50x there height here's how" then does nothing but show people recording them with ballet music saying "we can learn a lot about these creatures for robotics" never even explan why they can jump so high; then here's this video which is buried in the search results that not only has a great visual aid but gets to the point. Excellent Video
Wow. I don't think most folks realize what a brilliant and novel mechanism this is. I just modeled this up in software to try to understand it. There is no human designed repeating mechanism that I can think of that accomplishes storing force and releasing it kinetically with even vaguely similar linkages (ok so a trebuchet is somewhat like this, but fundamentally dissimilar). I can't think of a single wind-up toy, robo-dog, crossbow, other similar kinetic weapon, car part, throwing machine, industrial machine, walking machine etc, that uses linkages like this. I could write paragraphs on why I think this is so novel, but just try to model it yourself and you'll see what I mean, the fact that the video model is using the very specific properties of strings for some of the linkages is critical, the efficiency of force transfer is amazing, and the angles are critical.
Glad you like it. I wonder if it isn't used very often is that there aren't many places it would be useful outside scrapheap challenge (junkyard wars). Either that or it is just much better suited to muscles than rotary machines. If you scaled it up and used winches the release on the smaller winch would be difficult to achieve safely and reliably. Plus you have a system that needs two actuators with limit switches to achieve a single effect... It is very cool either way.
Good video presenting information that I haven't seen before. Just lots of fact sources mentioning they can jump high but without any actual description of why. It never gets relevant or interesting without the "why" covered.
on my quest to design and build a functional prototype "mach 5 speed racer" I would need this principle to get the vehicle to jump. it's the compression of the "spring" AND the shift of leverage that does it. thank you for amazing work. could we make a jumping strandbeest? how do bumblebees and beetles fly? if you are content with the answer, why doesn't gravity, momentum and inertia splatter them into goo with the amount of force required to do the things they clearly do easily everyday?
If you want a vehicle to jump, some kind of mechanism like this may well make sense, you definitely want to store energy in a way that is easily accessible. When you scale things down the accelerations they can' cope with are higher, because the strength of a muscle, bone etc will go as the square of its size, but the mass will increase as the cube. So if you halve its size you will double the acceleration it can cope with, and double the acceleration a muscle can produce. So a beetle or a bee at our size would rip itself apart (or not be strong enough to work), but at its scale it is fine. I think the aerodynamics are also very different from an aeroplane, but are now understood.
I am looking in nature to design the ultimate shock absorber and I wonder if you think this mechanism could be a possible candidate? Thank you in advance.
As is this wouldn't be a good shock absorber as there isn't really any mechanism for absorbing energy. In a car the shock absorber is there to stop the spring bouncing for ages when you go over a bump. I don't know enough about cars suspensions to tell you if this would be a useful geometry, my guess is that you don't want a car suspension to get less stiff the more it is compressed so no. If you wanted a car to jump in the air, it may be useful.
