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SUMMARY:Principles of lossless adjustable one-ports - Malcolm Smith\, Univ
 ersity of Cambridge
DTSTART:20200206T140000Z
DTEND:20200206T150000Z
UID:TALK134389@talks.cam.ac.uk
CONTACT:Alberto Padoan
DESCRIPTION:This talk explores the possibility to construct two-terminal m
 echanical devices (one-ports) which are lossless and adjustable.  To be lo
 ssless\, the device must be passive (i.e. not requiring a power supply) an
 d non-dissipative.  To be adjustable\, a parameter of the device should be
  freely variable in real time as a control input.  For the simplest lossle
 ss one ports\, the spring and inerter\, the question is whether the stiffn
 ess and inertance may be varied freely in a lossless manner.  It will be s
 hown that the typical laws which have been proposed for adjustable springs
  and inerters are necessarily active and that it is not straightforward to
  modify them to achieve losslessness\, or indeed passivity.  By means of a
  physical construction using a lever with movable fulcrum device laws will
  be derived for adjustable springs and inerters which satisfy a formal def
 inition of losslessness.  A construction method will be described which do
 es not require a power supply for physically realisable translational and 
 rotary springs and inerters.  The analogous questions for lossless adjusta
 ble electrical devices will be discussed.
LOCATION:Cambridge University Engineering Department\, Seminar Room JDB
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