Model-based control of remote actuation based on cable-conduit transmissions
Date
2018
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Delaware
Abstract
In the field of rehabilitation robotics, wearable systems need to optimize mass
distribution to reduce dynamic loading on distal joints. When this optimization requires
actuators be placed at locations distant from the joint they actuate, a cableconduit
transmission can be used to transmit forces to where they are needed. While
desirable for their low mass and flexibility, cable-conduit transmissions introduce large
frictional forces into the system that may result in the non-natural motion of the interacting
individual. Model based controllers can reduce the dynamic loading introduced
by cable-conduit transmissions, but presently there exists no model suitable for controller
use when the environment is non-passive. ☐ This work presents a new dynamic model of a cable-conduit transmission designed
to model interactions with non-passive environments, such as a human physically
interacting with a cable-conduit actuated robot. This non-linear model features
bi-directional propagation of motion within the transmission and captures the associated
frictional phenomena. The model is validated in a physical prototype through
experiments involving interaction with a human subject. To enable use in a real-time
controller application, a novel solution method, that operates 2 orders of magnitude
faster than traditional methods, is described and proven. ☐ The proposed model is evaluated for use as a tool to estimate states and mechanical
parameters during system operation, combining information from redundant
noisy sensors. Finally, designs for control schemes utilizing the model are discussed,
and several simulations are conducted to demonstrate improved system performance
when using a model-based controller. Development of this model will allow for future
researchers to include model-based low level control in their devices, improving
performance.
Description
Keywords
Applied sciences