Page 435 - Mechatronics with Experiments

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JWST499-c07
JWST499-Cetinkunt
ELECTROHYDRAULIC MOTION CONTROL SYSTEMS 421

Four-way valve Hydraulic cylinder
Engine

Hydraulic
pump

Relief
valve

Hydraulic reservoir

FIGURE 7.11: A manually operated hydraulic circuit for the cylinder motion of an excavator
linkage. The main directional valve is actuated via a mechanical pedal by an operator.

P.S
Command _ PID controller Amplifier
speed knob +
Speed sensor

Valve
Tool
Pump
I.C. engine

Hydraulic
motor
Tank
FIGURE 7.12: An electrohydraulic closed loop speed control system example for a service
truck.