Electric power steering system having fail-safe control module operation

摘要

An electric power steering system is provided. It comprises a steering assist assembly and a motor assembly that actuates the steering assist assembly. A control module that provides steering assist commands to the motor assembly, the control module including a circuit board having a first portion having circuits thereon and a second portion that includes at least one sensor circuit that receives signals from at least one sensor subsystem. A potting material coats only the first portion of the circuit board.

主权项

1. An electric power steering system comprising:
a steering assist assembly; a motor assembly that actuates said steering assist assembly; a control module that provides steering assist commands to said motor assembly, said control module including a circuit board having a first portion having at least one protected circuit thereon and a second portion that includes at least one exposed sensor circuit that receives signals from at least one sensor subsystem; and a potting material coating only said first portion of said circuit board; the at least one exposed sensor circuit being unprotected from exposure to contamination; the at least one exposed sensor circuit connected to the at least one protected circuit so as to provide, together with the protected circuit, a primary function of the electric power steering system; the at least one exposed sensor circuit connected to the at least one protected circuit and configured to operate, together with the protected circuit, in a fail-safe mode following impairment of the at least one exposed sensor circuit; the fail-safe mode characterized in that, following impairment of the at least one exposed sensor circuit, the at least one exposed sensor circuit and the at least one protected circuit continue to provide said primary function and a warning is issued indicative of the at least one exposed sensor circuit being exposed to contamination.