Electric seat motor absolute sensor diagnostics

A seat suspension system, comprising:

• a suspension mechanism coupling a vehicle seat to a vehicle body;
• an output shaft coupled to the suspension mechanism to move the vehicle seat relative to the vehicle body;
• a motor shaft coupled to a gear box and to drive the output shaft;
• a first rotational position sensor configured to measure a rotational position of the motor shaft and to generate a motor position signal representing the rotational position of a motor shaft;
• a second rotational position sensor configured to measure a rotational position of the output shaft and to generate an output signal representing the rotational position of the output shaft;
• and
• a controller configured to:
• determine a diagnostic indicator value as a function of the motor position signal and the output signal;
• and
• determine, based on the diagnostic indicator value, an accuracy of the output signal to represent the rotational position of the output shaft.

A controller for a seat suspension system comprising:

• a processor;
• and
• a memory including instructions that, when executed by the processor, cause the processor to:
• receive, from a first rotational position sensor, a motor position signal representing a rotational position of a motor shaft, the motor shaft being coupled to an output shaft, such that rotation of the motor shaft causes rotation of the output shaft;
• receive, from a second rotational position sensor, an output signal representing a rotational position of the output shaft coupled to a suspension mechanism to move a vehicle seat relative to a vehicle body;
• determine a diagnostic indicator value as a function of the motor position signal and the output signal;
• determine, based on the diagnostic indicator value, an accuracy of the output signal to represent the rotational position of the output shaft;
• determine the diagnostic indicator value indicating an unhealthy or faulted condition;
• and
• automatically perform, in response to determining the diagnostic indicator value indicating an unhealthy or faulted condition, a responsive action including at least one of:
• producing a warning, or operating the seat suspension system in a mode that does not use the second rotational position sensor.