US 12,015,398 B2
Robust ‘hands on steering wheel’ classification based on a relative measurement system
Thomas Faber, Schweich (DE); Frank Althaus, Saarbrücken (DE); Thomas Meyers, Wiersdorf (DE); Oliver Lion, Merzig (DE); Laurent Lamesch, Reichlange (LU); Michael Pütz, Trier (DE); and Alan Koehler, Igel (DE)
Assigned to IEE INTERNATIONAL ELECTRONICS & ENGINEERING S.A., Echternach (LU)
Appl. No. 18/038,739
Filed by IEE INTERNATIONAL ELECTRONICS & ENGINEERING S.A., Echternach (LU)
PCT Filed Nov. 24, 2021, PCT No. PCT/EP2021/082823
§ 371(c)(1), (2) Date May 25, 2023,
PCT Pub. No. WO2022/112330, PCT Pub. Date Jun. 2, 2022.
Claims priority of application No. LU102243 (LU), filed on Nov. 25, 2020; and application No. LU102444 (LU), filed on Jan. 21, 2021.
Prior Publication US 2023/0403007 A1, Dec. 14, 2023
Int. Cl. H03K 17/96 (2006.01); B62D 1/04 (2006.01)
CPC H03K 17/962 (2013.01) [B62D 1/046 (2013.01); H03K 2217/96071 (2013.01); H03K 2217/960735 (2013.01); H03K 2217/96078 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A method of operating a capacitive sensing device that includes:
at least one capacitive sensor having at least one sense electrode,
a measurement signal source configured to provide an alternating electric measurement signal comprising at least three fixed predefined signal frequencies at least to the at least one sense electrode,
an impedance measurement circuit configured to determine an unknown complex impedance of the at least one sense electrode from a response to the provided electric measurement signal,
the method comprising at least the following steps:
operating the measurement signal source to provide an alternating electric measurement signal comprising at least three fixed predefined signal frequencies to the at least one sense electrode,
by the impedance measurement circuit, measuring a response to the alternating electric measurement signal to determine an unknown complex impedance of the at least one sense electrode,
the method further comprising at least the following steps that are to be executed for each of the at least three fixed predefined signal frequencies:
determining a predefined number of momentary values of the unknown complex impedance,
determining statistical quantities and signal parameters regarding the determined momentary values,
eliminating from the determined momentary values a frequency portion up to a predefined hand touch movement lower limit frequency,
eliminating from the determined momentary values a frequency portion from a predefined high-frequency limit down to a predefined hand touch movement upper limit frequency for obtaining remaining determined momentary values,
excluding the respective determined momentary values if at least one determined statistical quantity exceeds a predefined critical threshold value,
using the eliminated frequency portion up to the lower limit frequency of the determined momentary values for calculating a momentary reference value for the unknown complex impedance,
and further comprises the steps of
using the remaining determined momentary values for determining a signal classification by checking a fulfillment of at least one predefined condition that includes the momentary reference value for the unknown complex impedance, and
generating an output signal that is representative of the result of the step of checking the fulfillment of the at least one predefined condition.