(Georgia Institute of Technology, 2013-08-20)
MacNair, David Luke
This work explores the representations and mathematical modeling of biologically-inspired robotic muscles called Cellular Actuator Arrays. These actuator arrays are made of many small interconnected actuation units which work together to provide force, displacement, robustness and other properties beyond the original actuator's capability. The arrays can also exhibit properties generally associated with biological muscle and can thus provide test bed for research into the interrelated nature of the nervous system and muscles, kinematics/dynamics experiments to understand balance and synergies, and building full-strength, safe muscles for prosthesis, rehabilitation, human force amplification, and humanoid robotics.
This thesis focuses on the mathematical tools needed bridge the gap between the conceptual idea of the cellular actuator array and the engineering design processes needed to build physical robotic muscles. The work explores the representation and notation needed to express complex actuator array typologies, the mathematical modeling needed to represent the complex dynamics of the arrays, and properties to guide the selection of arrays for engineering purposes. The approach is designed to aid automation and simulation of actuator arrays and provide an intuitive base for future controls and physiology work. The work is validated through numerical results using MatLab's SimMechanics dynamic modeling system and with three physical actuator arrays built using solenoids and shape memory alloy actuators.
(Georgia Institute of Technology, 2012-04-06)
Henderson, Gregory Clark
A control method is proposed for exercising specific muscles of a human's lower body. This is accomplished using an exoskeleton that imposes active force feedback control. The proposed method involves a combined dynamic model of the musculoskeletal system of the lower-body with the dynamics of pneumatic actuators. The exoskeleton is designed to allow for individual control of mono-articular or bi-articular muscles to be exercised while not inhibiting the subject's range of motion.
The control method has been implemented in a 1-Degree of Freedom (DOF) exoskeleton that is designed to resist the motion of the human knee by applying actuator forces in opposition to a specified muscle force profile. In this research, there is a discussion on the model of the human's lower body and how muscles are affected as a function of joint positions. Then it is discussed how to calculate for the forces needed by a pneumatic actuator to oppose the muscles to create the desired muscle force profile at a given joint angles. The proposed exoskeleton could be utilized either for rehabilitation purposes, to prevent muscle atrophy and bone loss of astronauts, or for muscle training in general.