Hydraulic and Pneumatic Actuators and their Application Areas

Hydraulic and Pneumatic Actuators and their Application Areas

Abstract

Modern robotic systems are difficult. drives are a mechanical part of this systems. Three types of drives are basically used now: electric, pneumatic and hydraulic. Each type has its own advantages and disadvantages.

In this paper I’m going to tell you about pneumatic and hydraulic actuators, about their advantages and disadvantages, about their types and variants of design.

Introduction

Modern robotic systems are difficult. drives are a mechanical part of this systems. Three types of drives are basically used now: electric, pneumatic and hydraulic. Each type has its own advantages and disadvantages.

In this paper I’m going to tell you about pneumatic and hydraulic actuators, about their advantages and disadvantages, about their types and variants of design. Functional schemes of pneumatic and hydraulic drives are similar. We’ll discuss one of them.

Automatic pneumatic drive, its function scheme is shown in the fig. A, generally represents a complex of devices and consists of a source of gas energy, units of gas networks and mains (UGM), pneumatic amplifiers (PA), pneumatic engines (PE), the mechanism of transfer (MT) and directors, converting and summing device (CSD), amplifiers of capacity of electric signals (ACE), electromechanical converters (EMC), devices of feedbacks (DF), adjusting circuits (AC) and internal feedbacks (IF).

All complex of these devices is intended for amplification and transformation of a low-power input signal into mechanical moving of the target shaft of the executive mechanism.

The initial drive size of a drive is electric signal Uip of low power Nip which is corrected and amplifies with the help of additional feed energy of the capacity amplifier in the con-verting and summing device (CSD). The amplified control signal moves on electromechanical converter (EMC) that accordingly moves the managing body of pneumoamplifier (PA) on the size value z. The angle of the turn of electromechanical converter’s (EMC) axis in direct ratio corresponds to the size value z. Due to rigid mechanical connection of the axis of the torque motor with the axis of pneumatic amplifier (PA) jet tube of or with the motion of the choke, the valve or the rod of PA valve, control of the gas stream proceeding from a source of gas energy (GG), through UGM and PA in pneumatic engine (PE) is occurred. Proportinally to the value of the main signal Uip, the gas stream N0 is moved into the engine that transforms this stream into mechanical displacement of the X enging output link. For connection of the engine with loading capacity Nc stipulates the mechanism of transfer (MT) which rigidly connects the moving of the rod of the engine with the movement of the loading Yop of the working mechanism.

To increase dynamic properties and accuracy of reproduction of the input signal the au- tomated drive has feedbacks EF and DF and adjusting circuits (AC) on speed, acceleration 3and loading.

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