Non-Linear Trajectory Control of Tensegrity Prosthetic (ProTense) Leg
Abstract
There has been a continuous rise in the number of amputees over the past decades and estimates
put the number of amputees in the US alone at over 3 million by 2050. With the rising amputee
population, the development of better prosthesis is needed to return quality of life to millions.
The field of prosthetic development is active, with improved prosthesis entering the market owing
to the advent of new materials and control strategies. The improvement in sensor technology and
understanding of the bio-mechanics of the limbs have further bolstered the confidence of engineers
to provide prosthetic legs with added power and degrees of freedom allowing the amputees to run
faster, trek steeper and scale new heights.
Tensegrity, a word coined by Buckminster Fuller in the 1960s, is an amalgam of the words
tension and integrity. A tensegrity structure is a prestressable network of bars and strings with
specific boundary conditions and external forces applied at the nodes. Tensegrity structures were
introduced as an art form by Kenneth Snelson. Civil engineers paid little attention to the Tensegrity
due to absence of a full dynamical model to define it which people like Skelton provided. More
recently, the concept of tensegrity became popular with roboticists and control theorists for making
complex robots manipulated by strings as actuators. The shape control capability of tensegrity
structures without change in stiffness and the capability to provide minimal mass solutions to many
engineering problems can be exploited for various applications. In the last 25 years tensegrity
has come to be associated with various inquiries into the nature of living structure by Professors
like Donald E. Ingber, who has claimed tensegrity to be the best explanation of the working of a
cytoskeleton of the cell in his journal, ‘The Architecture of life’.
This work describes an initial effort aimed at applying the huge potential of tensegrity structures
into the field of leg prosthetics. The objective is to provide a stable and comfortable prosthetic leg
for above/below knee amputees with both strong and weak residual leg for motion in the sagittal
plane while they walk on level ground.
Citation
Vishala, FNU N/A (2018). Non-Linear Trajectory Control of Tensegrity Prosthetic (ProTense) Leg. Master's thesis, Texas A & M University. Available electronically from https : / /hdl .handle .net /1969 .1 /174368.