704 research outputs found
Arthrobots
This paper describes a class of robotsââarthrobotsââ inspired, in part, by the musculoskeletal system of arthropods (spiders and insects, inter alia). An exoskeleton, constructed from thin organic polymeric tubes, provides lightweight structural support. Pneumatic joints modeled after the hydrostatic joints of spiders provide actuation and inherent mechanical compliance to external forces. An inflatable elastomeric tube (a âballoonâ) enables active extension of a limb; an opposing elastic tendon enables passive retraction. A variety of robots constructed from these structural elements demonstrate i) crawling with one or two limbs, ii) walking with four or six limbs (including an insect-like triangular gait), iii) walking with eight limbs, or iv) floating and rowing on the surface of water. Arthrobots are simple to fabricate, inexpensive, light-weight, and able to operate safely in contact with humans.Chemistry and Chemical Biolog
Effective Viscous Damping Enables Morphological Computation in Legged Locomotion
Muscle models and animal observations suggest that physical damping is
beneficial for stabilization. Still, only a few implementations of mechanical
damping exist in compliant robotic legged locomotion. It remains unclear how
physical damping can be exploited for locomotion tasks, while its advantages as
sensor-free, adaptive force- and negative work-producing actuators are
promising. In a simplified numerical leg model, we studied the energy
dissipation from viscous and Coulomb damping during vertical drops with
ground-level perturbations. A parallel spring-damper is engaged between
touch-down and mid-stance, and its damper auto-disengages during mid-stance and
takeoff. Our simulations indicate that an adjustable and viscous damper is
desired. In hardware we explored effective viscous damping and adjustability
and quantified the dissipated energy. We tested two mechanical, leg-mounted
damping mechanisms; a commercial hydraulic damper, and a custom-made pneumatic
damper. The pneumatic damper exploits a rolling diaphragm with an adjustable
orifice, minimizing Coulomb damping effects while permitting adjustable
resistance. Experimental results show that the leg-mounted, hydraulic damper
exhibits the most effective viscous damping. Adjusting the orifice setting did
not result in substantial changes of dissipated energy per drop, unlike
adjusting damping parameters in the numerical model. Consequently, we also
emphasize the importance of characterizing physical dampers during real legged
impacts to evaluate their effectiveness for compliant legged locomotion
HydroDog: A Quadruped Robot Actuated by Soft, Fluidic Muscles
This report presents the very first effort aimed to develop a legged terrestrial robot actuated by Hydro Muscles, which are elastic tubes actuated by fluid, constrained by fabric that extend and contract emulating life-like performance of biological muscles. The team designed and manufactured a 30-pound quadruped âdogâ using versatile aluminum extrusions and minimally machined components. The team tested and observed a variety of bounding gaits that resulted from different skeletal/muscular geometries and actuation times. These tests yielded varying jump heights and robot forward velocities. Future projects should extensively research optimal leg kinematics to maximize the mechanical power the muscles apply on the robot
Design of Soft, Modular Appendages for a Bio-inspired Multi-Legged Terrestrial Robot
Soft robots have the ability to adapt to their environment, which makes them
suitable for use in disaster areas and agricultural fields, where their
mobility is constrained by complex terrain. One of the main challenges in
developing soft terrestrial robots is that the robot must be soft enough to
adapt to its environment, but also rigid enough to exert the required force on
the ground to locomote. In this paper, we report a pneumatically driven, soft
modular appendage made of silicone for a terrestrial robot capable of
generating specific mechanical movement to locomote and transport loads in the
desired direction. This two-segmented soft appendage uses actuation in between
the joint and the lower segment of the appendage to ensure adequate rigidity to
exert the required force to locomote. A prototype of a soft-rigid-bodied
tethered physical robot was developed and two sets of experiments were carried
out in both air and underwater environments to assess its performance. The
experimental results address the effectiveness of the soft appendage to
generate adequate force to navigate through various environments and our design
method offers a simple, low-cost, and efficient way to develop terradynamically
capable soft appendages that can be used in a variety of locomotion
applications
HydroDog: A Quadruped Robot Actuated by Soft Fluidic Muscles
This report presents the very first effort aimed to develop a legged terrestrial robot actuated by Hydro Muscles, which are elastic tubes actuated by fluid, constrained by fabric that extend and contract emulating life-like performance of biological muscles. The team designed and manufactured a 30-pound quadruped âdogâ using versatile aluminum extrusions and minimally machined components. The team tested and observed a variety of bounding gaits that resulted from different skeletal/muscular geometries and actuation times. These tests yielded varying jump heights and robot forward velocities. Future projects should extensively research optimal leg kinematics to maximize the mechanical power the muscles apply on the robot
An Overview of Legged Robots
The objective of this paper is to present the evolution and the state-of-theart in the area of legged locomotion systems. In a first phase different possibilities for mobile robots are discussed, namely the case of artificial legged locomotion systems, while emphasizing their advantages and limitations. In a second phase an historical overview of the evolution of these systems is presented, bearing in mind several particular cases often considered as milestones on the technological and scientific progress. After this historical timeline, some of the present day systems are examined and their performance is analyzed. In a third phase are pointed out the major areas for research and development that are presently being followed in the construction of legged robots. Finally, some of the problems still unsolved, that remain defying robotics research, are also addressed.N/
HydroDog: A Quadruped Robot Actuated by Soft Fluidic Muscles
This report presents the very first effort aimed to develop a legged terrestrial robot actuated by Hydro Muscles, which are elastic tubes actuated by fluid, constrained by fabric that extend and contract emulating life-like performance of biological muscles. The team designed and manufactured a 30-pound quadruped âdogâ using versatile aluminum extrusions and minimally machined components. The team tested and observed a variety of bounding gaits that resulted from different skeletal/muscular geometries and actuation times. These tests yielded varying jump heights and robot forward velocities. Future projects should extensively research optimal leg kinematics to maximize the mechanical power the muscles apply on the robot
- âŠ