2 research outputs found
Comfort-Centered Design of a Lightweight and Backdrivable Knee Exoskeleton
This paper presents design principles for comfort-centered wearable robots
and their application in a lightweight and backdrivable knee exoskeleton. The
mitigation of discomfort is treated as mechanical design and control issues and
three solutions are proposed in this paper: 1) a new wearable structure
optimizes the strap attachment configuration and suit layout to ameliorate
excessive shear forces of conventional wearable structure design; 2) rolling
knee joint and double-hinge mechanisms reduce the misalignment in the sagittal
and frontal plane, without increasing the mechanical complexity and inertia,
respectively; 3) a low impedance mechanical transmission reduces the reflected
inertia and damping of the actuator to human, thus the exoskeleton is
highly-backdrivable. Kinematic simulations demonstrate that misalignment
between the robot joint and knee joint can be reduced by 74% at maximum knee
flexion. In experiments, the exoskeleton in the unpowered mode exhibits 1.03 Nm
root mean square (RMS) low resistive torque. The torque control experiments
demonstrate 0.31 Nm RMS torque tracking error in three human subjects.Comment: 8 pages, 16figures, Journa
Mechanism design and analysis of a proposed wheelchair-exoskeleton hybrid robot for assisting human movement
As a conventional mobile assistance device, a wheelchair makes people suffer
from skin injuries such as bed sores and ulcer, owing to sitting on a
wheelchair for a long period. And the wheelchair is barely able to adapt to
complex terrains, such as stairs. With the development of robotic technology,
the rise of lower-limb exoskeleton robotics provides a new means of motion
assistance, and provides training of motor ability. However, it can't support
a user to compete long-distance movement because a user need consume much
energy to keep balance. Considering the merits and demerits of wheelchairs
and exoskeletons, we propose a novel hybrid motion assistant robot that
combines both. The biggest challenge is the design of a mechanism that can
transform the robot from a wheelchair into an exoskeleton, as well as the
reverse transformation. To achieve this goal, the mechanism must be able to
achieve three configurations: the wheelchair configuration, the support
configuration, and the exoskeleton configuration. To reduce the weight of the
robot and make it more compact, the linkages and actuators in the mechanism
are designed to be reusable when the configuration changes. The mechanism is
designed based on the analysis of functional requirements, and distributed
synthesis of the mechanism is adopted. The kinematics and statics of every
configuration are discussed in detail, to obtain the most reasonable
dimensions using the particle swarm optimization algorithm. The mechanism
performance is simulated and verified using ADAMS software. Finally, an
experimental prototype is constructed for preliminary tests.</p