Controller:Control System Control a device using actuator,based on sampled sensor data Control loop compares measured value y(t)and reference r(t) Depends on correct control law computation,reference input,accuracy of measurements - Time between measurements of y(t),r(t)is the sampling period,T Small T better approximates analogue control but large T needs less processor time; if T is too large,oscillation will result as the system fails to keep up with changes in the input Control-law Vertical axis Left Aileron Reference computation Rudder nput:r间明 Elevator Right Aileron Longitudinal axis y() Lateral axis Sensor Device ActuatorController: Control System • Control a device using actuator, based on sampled sensor data – Control loop compares measured value y(t) and reference r(t) • Depends on correct control law computation, reference input, accuracy of measurements – Time between measurements of y(t), r(t) is the sampling period, T • Small T better approximates analogue control but large T needs less processor time; • if T is too large, oscillation will result as the system fails to keep up with changes in the input !