Tensegrity Prosthetics

Prosthetic devices straddle the divide between biologic concerns and robotic ones. Tensegrity prosthetics require robust materials, as well as sophisticated components that are difficult to manufacture.

Context: Tom Flemons Archive and Advantages of Tensegrity


Motivation for building tensegrity prosthetics

(Feb 23, 2014; repeated from Emulate Biological Systems by Modeling Force Vectors, not Anatomy) Prosthetic devices, and exoskeletons based on tensegrity straddle the divide between biologic concerns and robotic ones. I use biology as the starting point but proceed without constraint from there. My first assumption is that biology is tensegrity based. My second is that Nature parsimoniously selects for optimum form and function and that tensegrity geometry qualifies as the sin qua non means to achieve least energy efficient ambulation and durability (among other things). My third assumption then follows from this – that it should be possible from close observation with a tensegrity perspective to understand somewhat how nature ‘does the trick’ and from there to abstract out key elements of design and attempt to replicate them in compliant structures which can be animated using actuator algorithms.

Challenges in building tensegrity prosthetics

(Sept 5, 2015) But I honestly don’t know where to put my energies at this point. I am in the process of trying to build yet another tensegrity leg foot this time out of more robust materials but there are a few sticking points I haven’t figured out yet. Clearly building a robust model that could actually function as a prosthetic leg would be a useful endeavor but it’s almost impossible to achieve without sophisticated components that I lack the ability to manufacture. Similarly I’m trying to come up with a gripper that would function as a hand and running into problems there as well.

(Feb 21, 2017) There are enormous advantages to utilizing tensegrity principles in the implementation of robotic and prosthetic systems but also some very substantial problems present themselves. Notably issues of decentralized (distributed) control systems, assembly algorithms, and form finding must be solved. I’m not a roboticist or a computer scientist – my contribution is form finding and suggestions as to how to assemble discrete tensegrity modules into mechanical linkages. Revolute and prismatic joints can be built in to the structures to allow for ROM and DOF and I have found a way to create bistable joints which allow for articulated segments to be controlled with minimal energy expenditure.

Four lever linkage – application to prosthetics

(July 16, 2015) The four-lever linkage may prove useful in designing complex tensegrity joints in robotics and prosthetics as well as modelling complex joints in the body.