
Jansen's linkage is a planar
leg mechanism
A leg mechanism (walking mechanism) is a mechanical system designed to provide a propulsive force by intermittent frictional contact with the ground. This is in contrast with wheels or continuous tracks which are intended to maintain continuous ...
designed by the kinetic sculptor
Theo Jansen
Theodorus Gerardus Jozef Jansen (; born 14 March 1948) is a Dutch artist. In 1990, he began building large mechanisms out of PVC that are able to move on their own and, collectively, are titled ''Strandbeest''. The kinetic sculptures appear to ...
to generate a smooth walking motion.
Jansen has used his mechanism in a variety of
kinetic sculptures which are known as (
Dutch
Dutch commonly refers to:
* Something of, from, or related to the Netherlands
* Dutch people ()
* Dutch language ()
Dutch may also refer to:
Places
* Dutch, West Virginia, a community in the United States
* Pennsylvania Dutch Country
People E ...
for "beach beasts"). Jansen's linkage bears artistic as well as mechanical merit for its simulation of organic walking motion using a simple rotary input. These leg mechanisms have applications in
mobile robotics and in
gait analysis
Gait analysis is the systematic study of animal locomotion, more specifically the study of human motion, using the eye and the brain of observers, augmented by instrumentation for measuring body movements, body mechanics, and the activity of the ...
.
The central '
crank
Crank may refer to:
Mechanisms
* Crank (mechanism), in mechanical engineering, a bent portion of an axle or shaft, or an arm keyed at right angles to the end of a shaft, by which motion is imparted to or received from it
* Crankset, the compone ...
' link moves in circles as it is actuated by a rotary actuator such as an electric motor. All other links and
pin joints are unactuated and move because of the motion imparted by the crank. Their positions and orientations are uniquely defined by specifying the crank angle and hence the mechanism has only one
degree of freedom
Degrees of freedom (often abbreviated df or DOF) refers to the number of independent variables or parameters of a thermodynamic system. In various scientific fields, the word "freedom" is used to describe the limits to which physical movement or ...
(1-DoF). The kinematics and dynamics of the Jansen mechanism have been exhaustively modeled using circle intersection method and bond graphs (Newton–Euler mechanics).
These models can be used to rate the actuator torque and in design of the hardware and controller for such a system.
Illustrations
File:Strandbeest-Walking-Animation.gif, Animation of one leg
File:Strandbeest Leg Proportions.svg, Length of the rods
File:Strandbeest--Full-Walking-Animation.gif, Animation of six legs
References
External links