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.