| 摘要 |
An adaptive, discrete-time sliding mode controller (SMC) is disclosed which detects and adapts to gain variations in the controlled plant. The overall control effort is generated by combining a linear control effort with a discrete-time sliding mode control effort generated by switching between gains in order to drive the system's phase states toward a sliding line trajectory. A sliding mode variable sigmak defines the position of the system phase states relative to the sliding line. The SMC controller is designed such that the sliding mode variable sigmak crosses the sliding line and changes sign at every sample interval. For the nominal plant gain, the SMC controller is also designed such that the magnitude of the sliding mode variable sigmak+1=-sigmak will remain constant (sigmak+1=-sigmak) and substantially constrained towhere DELTA and lambd are predetermined design constants. The deviation in if the magnitude of sigmak from nominal is a direct measure of the deviation in the plant gain. Accordingly, the present invention measures the error between the measured magnitude of sigmak and the nominal magnitude, and uses this measured error to adapt to variations in the plant gain.
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