Position detection apparatus and position control apparatus
View Patent ↗The invention provides a position detection apparatus comprising: a base part, a moving part movable relatively with respect to the base part, a position detection part that detects a position of the moving part relative to the base part on the basis of a magnetic flux change to produce position data, a temperature detection part that detects an ambient temperature, a position correction part that calculates a correction value on the basis of a difference between the position data and a given reference value and the ambient temperature, and corrects the position data on the basis of the calculated correction value to produce a first corrected position data, and a linearity correction part that corrects the first corrected position data on the basis of the correction value for nonlinearity of the position detection part to produce a second corrected position data, wherein: the position detection part is capable of detecting position value as far as a position area where, within a position range of relative movement of the moving part to the base part, the magnetic flux change in association with a change in an amount of the relative movement is nonlinear.
1. A position detection apparatus, comprising:
a fixed base,
a moving part movable relatively with respect to the fixed base,
a position detector that detects a position of the moving part relative to the fixed base on the basis of a magnetic flux change to produce first position data,
a temperature detector that detects an ambient temperature,
a controller configured to:
apply a correction computation to the first position data on the basis of the ambient temperature and a difference between the first position data and a given value based on a reference voltage of the position detector to produce second position data on the basis of the following equation (1); and
apply a computation to the second position data to make a correction for nonlinearity of the position detector to produce third position data,
wherein:
the position detector detects position data as far as a position area where, within a position range of relative movement of the moving part to the fixed base, the magnetic flux change in association with a change in an amount of the relative movement is nonlinear:
Y=X−A* ( X−B )*( T−C ) Equation (1)
where X is the first position data produced out of the position detector,
A is a coefficient based on temperature characteristics,
B is a value based on the reference voltage of the position detector,
C is a value based on a reference temperature,
T is the ambient temperature, and
Y is the second position data.
2. The position detection apparatus according to claim 1 , wherein: the position detector is configured to produce the first position data by using a Hall element.
3. A position control apparatus, comprising:
the position detection apparatus according to claim 1 , and
a driving actuator that applies a driving force to the moving part to move the moving part,
wherein the controller further controls the driving force of the driving actuator on the basis of target position data and the third position data.