ABSTRACT
An actuator is an output device for the conversion of supply energy into useful work. The output signal is controlled by the control system, and the actuator responds to the control signals via the final control element. The fluid power actuator can be described under two groups, linear or rotary: linear motion, rotary motion, air motor and hydraulic motor, and rotary actuator. The compact rotary actuator is suited to robotics and materials handling applications where there is limited space. Salient design features of rotary actuators are: small and robust, precision machined and hence very efficient, available with contactless sensing, adjustable for angular displacement, constructed from lightweight material, and easy to install. A number of different types of hydraulic motor exist, this chapter discusses the following two types of hydraulic motor: hydraulic gear motor and hydraulic high torque, low speed motor.
