Control Systems
r reference valuee errorC controlleru output from controller to control PP plant, controlled systemy state of PF feedback to controller
Open loop control
Closed loop controlactuators
sensorsdigital
physical
A centrifugal governor is a specific type of governor that controls the speed of an engine by regulating the amount of fuel (or working fluid) admitted, so as to maintaina near constant speed whatever the load or fuel supplyconditions. It uses the principle of proportional control.
Controller Motor
Wheel
Rotation sensor
PowerSetpoint 0
Controller Motor
Wheel
Rotation sensor
PowerSetpoint 0
error = Setpoint - counts
Power = Pgain * error
0 countserror > 0Power > 0
error < 0Power < 0
error = Setpoint - counts
Power = Pgain * error - Dgain * velocity
0 countserror > 0Power > 0P term > 0
velocity >0D term < 0
error < 0Power < 0P term < 0
velocity <0D term > 0
Embedded Java
The leJOS API classes provide access to thehardware. Especially the i/o devices.
Battery
Button
LCD
Sound
The LCD is a 100 x 64 pixel black & white graphical display.
When the LCD class is used to output text each character or digit has a width of 6 pixelsand a height of 8 pixels. This means that there is room for 8 lines of 16 characterson the LCD.