1. CHAPTER 4: CONTROL OF ACTUACTOR

2. Learning Outcomes: Upon completion this chapter, student should be able:- 1. Explain of concept pneumatic, hydraulic and motor devices 2. Compare the three actuating systems 3. Contents 1. Basic pneumatic and hydraulic system 2. Basic electrical motor system 4. Basic pneumatic system Pneumatic drive: are generally used for smaller robots. These robots, with fewer degrees of freedom, carry out simple pick-and-place material handling operations. 5. Advantages and disadvantages of Pneumatic Actuators. Advantages: low cost; high speed of moving; ease at reversion movements; high reliability of work; explosion and fire safety; ecological purity Disadvantages: compressibility of the air ; impossibility to receive uniform and constant speed of the working bodies movement difficulties in performance at slow speed limited conditions - use of compressed air is beneficial up to the definite values of pressure compressed air requires good preparation. 6. Basic hydraulic system Hydraulic drive: gives a robot great speed and strength. These systems can be designed to actuate linear or rotational joints. The main disadvantage of a hydraulic system is that it occupies floor space in addition to that required by the robot. 7. Types of hydraulic actuator Linear actuator (hydraulic cylinder) Provides motion in straight line Linear displacement depends on stroke length (length of actuator) Usually referred to as cylinders, rams (single acting cylinders) or jacks (cylinder used for lifting) Rotary actuators (Hydraulic motors) Produces continuous rotational motion Pump shaft is rotated to generate flow, a motor shaft is caused to rotate by fluid being forced into the driving chambers 8. Semi rotary actuators Produces non-continuous rotational motion Limited to less than one revolution (