tailieunhanh - Components of Servos

From a basic hardware point of view it is important to understand the steady-state equations of a hydraulic and electric actuator. The majority of hydraulic positioning or machine feed drives use a rotary actuator with a servo valve attached to the motor to minimize the amount of trapped oil under compression. By minimizing the volume of oil that is trapped between the servo motor and servo valve, the hydraulic resonance will be increased and the drive made more stable. | 3 Components of Servos HYDRAULIC ELECTRIC CIRCUIT EQUATIONS From a basic hardware point of view it is important to understand the steady-state equations of a hydraulic and electric actuator. The majority of hydraulic positioning or machine feed drives use a rotary actuator with a servo valve attached to the motor to minimize the amount of trapped oil under compression. By minimizing the volume of oil that is trapped between the servo motor and servo valve the hydraulic resonance will be increased and the drive made more stable. The hydraulic flow equations for a fixed displacement servo motor are shown in Figure 1. The steady-state direct current DC motor equations are also shown in Figure 1. The voltage and torque equations include the motor back emf constant Ke and the torque constant KT . These motor constants are used throughout the basic and advanced portions of this book. Therefore it is important to know where to find them and how they are used in the forthcoming servo calculations. ACTUATORS ELECTRIC It is important from the hardware point of view to be familiar with manufacturers motor specifications to find the design parameters such as Copyright 2003 by Marcel Dekker Inc. All Rights Reserved Fig. 1 Hydraulic and electric motor circuits. the voltage constant and torque constants that are required for servo drive calculations. Sample electric drive manufacturer specifications are included for DC and alternating current AC servo drives. DC motor specifications for Gettys motors are shown in Figure 2. AC brushless DC Allen-Bradley motor specifications are shown in Figure 3. The motor voltage and torque constants are included in these specifications. For all drive calculations the torque constants for a hot motor 408 C should be used wherever possible. Copyright 2003 by Marcel Dekker Inc. All Rights Reserved MOTOR DATA TYPICAL AT 25 c PARAMETER SYMBOL UNIT 3Ơ-1 30-2 OPERATING PARAMETERS Continuous Rated Torque at Stall TENV T. lb-in 299 335 Continuous

• Cơ sở dữ liệu
• steady state equations
• hardware point
• Hydraulic
• electric motor circuits
• Hydraulic
• actuator