Chebyshev's Lambda Mechanism


The Chebyshev's Lambda Mechanism is a four-bar mechanism that converts rotational motion to approximate straight-line motion with approximate constant velocity. The precise design trades off straightness, lack of acceleration, and the proportion of the driving rotation that is spent in the linear portion of the full curve.
The example to the right spends over half of the cycle in the near straight portion. Coupler point stays within 1% positional tolerance with intersecting the ideal straight line 6 times.
The Chebyshev's Lambda Mechanism is a cognate linkage of the Chebyshev linkage.
The linkage was first shown in Paris on the Exposition Universelle as "The Plantigrade Machine".
The Chebyshev's Lambda Mechanism looks like the Greek letter lambda, therefore the linkage is also known as Lambda Mechanism.
Chebyshev's Lambda Mechanism used in vehicle suspension mechanisms, walking robots and rover wheel mechanisms. In 2004, a study completed as a Master of Science Thesis at Izmir Institute of Technology, a new mechanism design introduced by combining two symmetrical Lambda Mechanism to distribute the force evenly on to ground with providing the straight vertical wheel motion.
Double Lambda Chebyshev Mechanism rover suspension design manufactured and tested in Earth Rover Project of Los Angeles City College Electronics Club