On-line diagnosis and compensation for parametric failures in linear state variable circuits and systems using time-domain checksum observers

A large class of real-time circuits and systems can be expressed in linear state variable form. Of particular interest are systems with sensors and actuators that can degrade over time or circuits that can suffer from parametric deviations due to electrical degradation. In the past, multiple checksum codes have been used for error detection and correction in linear systems. In this research, it is shown for the first time that under multi-parameter failures (variations), the transient checksum response (single checksum) to a system contains multi-parameter diagnostic information about the parametric failure. In other words, when a single checksum transient response is time-sampled, the resulting sampled values can be mapped to the critical parameters of the system that affect its performance under multi-parameter variations. The resulting information can be used to rapidly actuate adaption of relevant linear control mechanisms for the system (e.g. PID control) in order to restore system performance with very low correction latency. We make a case for this new “checksum observer” paradigm using motors, generators and a simple biquadratic filter. Preliminary results are presented and demonstrate the viability of the proposed ideas.