Actuators are devices that convert energy into a driving force to move the robot. They include devices such as hydraulic pistons, AC and DC Motors, Servo Motors, and Stepper Motors. They consist of a piston, which applies the force, and a stator, which houses the piston and whatever other mechanisms are used to drive the piston. There are three main types of actuators:


Hydraulic Actuators use a hydraulic system to achieve the force needed. The advantage of hydraulic actuators is that the direction of force can be reversed under full load with no damage and very quickly. Of course, a hydraulic system requires a hydraulic pump and that takes space and another motor to power it.


Pneumatic Actuators are similar to hydraulic, but instead use air to power the actuator. Also, a pressure sensor is used to regulate the air pressure to prevent damage to the system.


Electric Actuators use a solenoid to produce an electromagnetic field that drives the piston.  When voltage is applied, the solenoid generates an electromagnetic field that repels an opposing field placed on the piston.  A spring is used so that the piston will return to its original position after power is cut off.

The Rhino Robot uses an electric actuator for two reasons: space in the lab is limited and hydraulic and pneumatic tanks would make it cramped; and also we don't need the strength of hydraulic and pneumatic. Plus, they would be harder and more expensive to service.

Constructed by Charles Rodes (2001)