Abstract: A controller for a permanent magnet synchronous motor which includes a D-axis current command section and a Q-axis current command section. The D-axis current command section increases the command value of the D-axis current so as to set a judged value to be zero by leading the current phase when the judged value is positive. In addition, the D-axis current command section decreases the command value of the D-axis current when the judged value is negative. Moreover, the D-axis current command section holds the command value of the D-axis current at a predetermined minimum value when the decreasing command value of the D-axis current becomes smaller than the predetermined minimum value. The Q-axis current command section is responsible for supplying a command value of the Q-axis current.

Abstract: A constant travel speed control apparatus is for use in a vehicle and utilizes time delay control which is a kind of adaptive control for estimating an unknown term. A plurality of targeted paths, each having a certain waveform, for causing the actual speed of the vehicle to converge on a target speed are provided and an error vector is defined on the basis of the paths. The actual speed of the vehicle can be made to converge on the target speed thereof with a constant convergence performance along a target path in spite of the fluctuation of vehicle dynamic characteristics.

Abstract: Qualitative relations between changes in a charge voltage, a developer bias voltage and an exposure light intensity control voltage and change in an image density are investigated in advance, and a density error is derived by a difference between the density of the image of a reference mark and a target density. Respective variations of the charge voltage, developer bias voltage and exposure light intensity control voltage are derived on the basis of the qualitative relations and the density error, and thereby the charge voltage, developer bias voltage and exposure light intensity voltage are changed so as to decrease the density error.

Abstract: A control system for a physical plant has a state output detector for detecting operating conditions of the physical plant. A trajectory production unit produces desired operating conditions of the physical plant, and an error production unit produces error signals based on the detected operating conditions and the desired operating conditions. A control signal generator generates a control signal based on the detected operating conditions, the error signals, a control signal generated a predetermined time period ago, an error dynamics adjustment signal, and a control input signal. The control signal generator includes a control input signal generator and an error dynamics signal generator. The control input signal generator generates the control input signal based on a predetermined control relationship. The error dynamics adjustment signal generator generates the error dynamics adjustment signal and the predetermined time period based on a plurality of predetermined error dynamics relationships.

Abstract: An adaptive control system for vehicles using a time delay control method which applies a reference model for giving desired response characteristics, assumes that terms of an unknown section such as for variations of plant dynamics are constant for a minute time period, and estimates this variation of the unknown section to calculate a control input that follows said reference model.