Appeal 2007-3939
Application 10/448,725
We affirm.
Appellant’s invention relates to a method and apparatus for accurately
detecting the position of a rotor in an electrically commutated brushless
direct current (dc) spindle motor such as the type used in a data storage
device to rotate a data recording disc (Specification 1). According to
Appellant, the inductive rise time (RT) exhibits an approximate linear
function with respect to the rotor’s position within the commutation state
(Specification 10). This approximate linear relationship, relative to the next
commutation point the rotor will encounter during rotation, is used to
calculate a substantially accurate position for the rotor (id.). An
understanding of the invention can be derived from a reading of exemplary
independent claims 1 and 9, which are reproduced below:
1. A method comprising:
developing a model of a motor based on a response of a
winding of the motor to an application of a non-rotational inducing
current across the winding for a predetermined time period; and
determining a substantially accurate position of a rotor of the
motor within a first commutation state of an electrical revolution of
the motor in which the rotor resides based on the model.
9. An apparatus adapted to determine a first commutation state of
a motor that a rotor of the motor resides and determine a substantially
accurate position of the rotor within the first commutation state.
The Examiner relies on the following prior art reference in rejecting
the appealed claims:
Calfee US 5,982,571 Nov. 9, 1999
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