AC Servo Drives

Mechanisms belonging to the range of motion electronic products, AC servo drives operate on alternate voltage patterns. As electronic amplifiers, they serve to power electric servo motors that similarly operate on alternate voltage pattern.

As special electronic amplifiers they A) monitor control feedback signals received from motors. B) According to feedback signals received they make necessary adjustments. C) They form a part of a dynamical system.

The function of AC servo drives is guided by the ‘control theory’, which is a sub part of Physics and Mathematics. According to this theory, A) A controller, manipulates the input to a system. B) This manipulation is geared to achieving the desired effect on the output. C) Output variables follow a reference of time. A.C servo drives act as controllers or A.C electrical amplifiers.


"Motion theory" also controls the functioning of servo drives. As special electronic mechanisms, they control the velocity of mechanisms. After receiving a command signal from a control system geared to A.C voltage, they amplify such signals and after due amplification, they transmit electric current to a system. Automatically, the electric current transmitted will be proportionate to the received command signal.

The servo motor with an attached velocity sensor does the needful work of reporting the motor’s actual velocity back to servo drive. After a due comparison of motor’s actual velocity with the command velocity, AC servo drives contribute to altering the due voltage frequency. Thus any error in voltage frequency is corrected by A.C servo drives. Usually servo motors rotate at a velocity matching the control signal. Servo motor control ensures the due matching leading to the establishment with proper configuration and tuning- which is a combination of proportional and derivative gain.

A.C servo drives are not only easily available, but they are also compatible with different variety of motors. Use of A.C servo drives has manifold advantages. Forming an integral part of the servo system their additional feedback serves to detect unwanted motion. They usually accurately assess the commanded motion. Moreover they are better adjusted to changing speed, with a better life span; giving effective durability to a system.

Servo drives are generally of two types. 1) Digital servo deals with discreet tracking of signals. 2) Analog deals with continuous tracking of signals.  Servo drives which form an integral part of the servo system have an enormous role to play in industries involved with robotics, automation and any other kind reliant on motion theory.

Custom Servo drives - an Overview

Custom servo drives are a kind of cost effective and optimized servo drive which are designed according to the customers applications to meet their needs of form, cost, fit and function specifications. Mostly known as the “special electronic amplifiers”, a custom or standard servo drive is commonly used to control the motors of the electric servo.

Over the decades, the technology of servo controls has changed a lot with its size, rotational speed, and torque. Custom servo drives are one of the major developments in the world of servo drives. The custom servo is almost similar to its digital counterparts. They have the same gears, motors and cases and most importantly they have a “Feedback potentiometer or Pot” like the digitals.

Designs of the custom servo drives:

• Optimized packaging- form factors, special connectors
• Multi Axis- two and three axis packages and systems based on racks
• Power Ratings-voltage and custom current ratings
• Java Beans-“fill in the blanks” standard indexer functions
• Enhanced Firmware-standard compensation filters
• Performance Edge-temperature compensation, low noise
• Feedback-special encoders

Classification of custom servo drives:

Custom servo drives can be classified based on the shapes, electric circuitry, sizes, type of feedback, input power variations, command and performance signal. Every factor has a great value in making the decision of the actual price of the custom servo drive.

Usage of custom servo drives:

Nowadays, custom servo drives are usually used in various industries like packaging, robotics, textile, factories of CNC machining and printing. With the increasing usage, the need of custom servo controls has increased a lot.

Advantages of using custom servo drives:

• Power saving ability:  In a custom servo drive, no power is sent to the servo motor when the car is idle. When the signal of moving the car is received, the power is sent to the servo motor up to a maximum voltage and then the servo responses. The servo doesn’t responses until the power reaches the maximum. This helps to save the excess power from being wasted. 
• Immense Standing Torque: The quotients of the standing torques of the custom servo drives are very high.
•  Monitoring: The custom servo drive is able to monitor the feedback signals from the motors by making some subsequent adjustments.

It is a fact that custom servo drives are very essential for the industry which totally depends on the motion control. So, to grow your industry, switch on to custom servo drives.

Servo Drives – Facts and Features

Servo drives have revolutionized the way key industrial applications run today. Digital servo has taken the mechanism of motion control to a new height where it amplifies the signals and makes mechanical output faster and more effective.

Benefits of servo drives -

• Higher and more dynamic response
• Reliable
• Cost effective
• Higher productivity and performance
• Accurate output
• Flexibility that can share technologies across diverse types of machines
• Higher safety and hygiene protocols
• User friendly interface that is easily PC adapted for fluid control
• Comprehensive programmed software for easier manipulation
• Higher feedback and report system makes for stronger output functions
• Super speed internal and external communication system enabled across multiple platforms
• Regular and quick updates of speed, position and current status leading to machine precision
• Reduced errors in tracking
• High precision supply of current while saving energy
• Interface for analog reading to use older machines

Digital servo drives function across servomotors like torque, asynchronous and linear motors and the brushless PM AC motors due to high end modular design. Based on 32- bit 400MHz microprocessor, it can used as effectively as a singular product as in a comprehensive system. It can ease the way your machine performs this providing higher output or aid in the machine design. Effective servo drive functions offer complete digital control and manipulation of brushless servo motors, delivers increased current and velocity leading to high precision performance that is the need of the hour across industries. Multi level interfaces, effective feedback system and superior controllers.

Leading vendors design and offer different kinds of servo drives –

• Servo drives that can control low power application for smaller machines requiring less than 1.5 kw. This effectively reduces design time and commission time, as well as provide layouts and CAD drawings.
• Digital servo drives that can handle multiple applications through single-axis motion control. They have inherent dynamic brakes, velocity observer, tuner and suppression algorithms to provide more cost effective motion control output.
• A multi-axis servo drive can helps in decreasing engineering time by helping effectively in networking, programming and operations. Adds greater flexibility and handles global voltage volume needs.
• Some come with high end safety options and flexible designs that can function on multiple levels and interfaces.
• EtherNet Servo Drives standardize the entire communication network leading to faster commissioning and startups, precise and easier configuration. Allows effective control integration with high speed connectivity.
• Some have troubleshooting options built in them, with automatic capacity of motor recognition.

Important Facts behind Servo Motion Controller

Servo drives have been an integral part of efficient output ever since they came into being. The servo motion controller has further enhanced the way industries can work, with precision management of position, velocity and movement and therefore aligning the entire process uniformly. 

The key industries benefiting from servo control system include:

• Assembly line units
• Industrial Machines
• Packaging industries
• Semiconductor production facilities
• Textile mills
• Printing houses
• High end video game industries
• Robot manufacturing
• Medical Equipments

The various servo drive products range from the simple servo motors, DC motors, servo drives, gears, linear motion components and actuators, linear ball and lead screws, linear and rotary brushless servo motors among others. The servo motion controller enhances velocity and position of these machines and their electric motors for effective and efficient output. 

The wires in servo motion control:  The 3 wire connector –

1. One supplies five to six volts of positive charge (DC)
2. The second one serves as voltage ground
3. The third wire acts as the signal wire through which the receiver responds

Servo motion controller not only enhances machine performance but also anticipates mishaps. The in-built mechanism can read slightest of the errors thus acting as a checkpoint for your machine’s efficiency. 

Benefits of servo motion control –

•             Accelerate system development

•             Increase system bandwidth

•             Control velocity, forces and pressures

•             Monitor feedback signals

•             Adjust motion to avoid deviations

•             Managing point-to-point positions

•             Quicker response times leading to higher machine output

•             Electronic gearing

•             Address mechanical needs of improving the transient response timings

•             Reduce steady-state errors

•             Diminish loading parameters sensitivity

•             Decrease voltage fluctuations.

•             True asset utilization

•             Lower total production costs

The most commonly referred role of the servo drive is that of the mediator. The control system sends specific signals to the drive which they amplify from their end. Then they transmit the current to the motor to create and incite a motion and torque that is in sync with the original signal, thereby brining in a balance of power and output in the device. This improves performance by adjusting and anticipating change. 

The key functions of the servo motion controller include command tracking and addressing all disturbance rejection traits that lie in the system. Together they track, mange and streamline processes. It includes the drive or the amplifier, motion controller, sensors for tracking feedback along with a hydraulic pump or air cylinder acting as a linear actuator.