d1: DISTANCE ATOMS=1,3
d2: DISTANCE ATOMS=2,3
# moving restraint
MOVINGRESTRAINT ...
  ARG=d2
  STEP0=0    AT0=0.308439  KAPPA0=200000.0
  STEP1=5000 AT1=0.180000
  LABEL=steer
... MOVINGRESTRAINT
PRINT FILE=COLVAR ARG=d2,steer.d2_cntr,steer.d2_work STRIDE=1
ENDPLUMED
