(1) Actuators are classified into pneumatic, electric and hydraulic actuators according to the driving energy used.
(2) According to the form of output displacement, the actuator has two types: angular type and linear type.
(3) According to the law of action, the actuator can be divided into three types: switch type, integral type and proportional type.
(4) According to the input control signal, the actuator can be divided into several categories such as air pressure signal, DC current signal, electrical contact on-off signal, pulse signal and so on.
