Electronic assembly of printed circuit board

Here you can see the example of the process of drilling a printed circuit board (PCB) by a spindle CNC Drill Machine.

This is a step of PCB electronic assembly process.

Products that Servotronix provides include off-the-shelf products, custom servo drives for placement head mechanisms, and fully-custom drive systems for overall machine control.

Brushless Servo Drives-An Overview

Brushless servo drives are a kind of all digital, précised and DSP based servo drives, which are able to supply up to “32 A peak current” continuous. These servo drives are specially designed to control the velocity, torque or the position of the servo motors as well as for motion control. Often a Low voltage drive is used with the brushless servo drives to save energy by controlling the motion of the servo. Energy saving with the variable torque is an easy process, which only needs a little payment.

Brushless servo drives are specially designed for the brushless servo motors and these drives are completely suitable for the speed, torque, position, and applications of electronic line shafting. The brushless servo drives are commonly made to control the brushless servo motors, but they are also able to handle the brushed servo motors as well.

The brushless servo motor drives are a compact and completely housed unit with all front panel connection through the typical pluggable connectors. This feature has made this servo drives easier to service as well as easier to integrate.

Features and benefits of the Brushless servo drives are mentioned below:

• The brushless servo drives are generally available in three models, which cover the major part of the servo application including the motion control and low voltage drive
• Line-operated, 50/60 Hz, 115 - 240 VAC, available in single or three phase
• The “all digital design” simplifies the process of tuning and drive setup and also eliminates the chance of analog drift.
• Fast step power interface

·        Sinusoidal fluctuation vector power algorithm

• Step multiplier
• Typical placing of PID with anti-windup and feedforward technology
• Support for BLAC, Brush DC and BLDC servos

·        PC based modification through serial port

·        Disparity encoder input

How do the brushless servos help in motion control?

Motion control is a kind of automation in which the velocity or the position of a machine is controlled by using some kind of device like an electric motor, hydraulic pump, or a servo. This process is commonly used in the CNC machines or in the robotics.

These are the basics of Brushless servo motors. With the usage of low voltage drive technology, the servo drives are capable of consuming 25% more power at a speed of 63%.

Benefits of Pick and Place Servo Drives

 In an age of rapid industrialization and intense competition, manufacturers simply cannot afford to compromise on the speed and accuracy of the machines and assembly lines in their production units. Prudence thus lies in investing in servo systems that speed up the functions on the assembly line front and also add to the precision of the operations. Herein stems the importance of pick and place robots in an assembly process. These systems are commonly found in industrial automation processes and are used to sort components and place them in their appropriate slots in the line.

Pick and place servo drives systems are some of the most expensive components in an industrial assembly line but manufacturers usually do not hesitate to invest in these because of the advantages that installing one such system affords. The following are some of the benefits of pick and place systems:

• Speed: Pick and place robotic systems, by automating processes, speed up cycle times. This in turn, leads to faster production, a key requirement for businesses to prosper in a 24X7 world. A servo controlled pick and place system is especially considered matchless on this front.

• Precision: Pick and place systems are almost 100% accurate in their operations, much more than a human being can ever be. When quality is the key to retaining customers, this feature ensures that manufacturing units engaging pick and place systems are consistently able to outsmart competition.

• Reliability: Powered by servo control, pick and place systems, when in top-notch shape, can work round the clock on all days of the week. This enables a manufacturing unit to churn out products in almost no time at all. This in turn, leads to considerable revenues.

• Flexibility: A slight tweak in the programming controls or a few twists and turns of the tools are all that is needed to equip a pick and place system with the capability to deal with multiple applications. This flexibility makes installing such a system extremely cost-effective.

• Cost-Effectiveness: The afore-mentioned features combine to lend a high degree of cost-effectiveness to such systems. Cost effectiveness also accrues from the fact that pick and place systems empower businesses to take up orders in bulk and thus aid business expansion and also reap the benefits of large-scale production.

Advances in technology in recent times complemented by a drop in prices, have made pick and place systems more affordable. It is thus possible for even small-scale production unit owners to own such a servo control system and reap its benefits.

What Are Brushless servo drives?

Brushless servo drives are DSP based all-digital, precision servo drive amplifiers, which are able of supplying “16 A peak” current constant, as well as “32 A peak” up to 230 VAC. The brushless servo drives are designed to perfectly control the position or velocity and torque of a number of brushless torque and servo motors. The design of this servo drive simplifies the commissioning and set up of the brushless servo motors, as the system software of brushless servo drives needs little more than the ordinary ones.

Features of brushless servo drives:

• Several models which cover the major parts of the requirements of the servo application
• Line operated, 50/60 Hz, 115-240 VAC, single or three phase
• The complete digital design of brushless servo drives simplifies the drive tuning and drive set up and removes the analog drift
• Complete fault protection and “optically isolated I/O”
• PWM, ±10VDC, encoder-follower and step-direction control inputs accommodated
• Internal regenerative power control circuit, which requires an external resistor
• Graphical client interface based on PC for motion control, monitoring and commissioning. This interface is attached with the drive through an “optically isolated USB port”.

Benefits of brushless servo drives:

• High efficiency or power saving- The original drive technology of brushless servo drives use low power and offer a high efficiency. It represents a great money saving technique on the 24/7 application than the ordinary servo drives
• High inertial loads- The brushless servo drives use “sophisticated motion control algorithms” to take the advantage of high-torque capacity, offering direct-drive of high inertia loads such as the belt drives and flywheels. It is much more than the traditional servos. This servo drive also provides a smooth responsive pointing control.
• More torque in a lesser price- Brushless servo drives provides 2-4 times more constant torque in lesser price ($300-400 less) than the conventional servo motors.

AC Servo Drives – The Present Industrial Requirement

Servo drives are specially made electronic amplifier that is used to boost or run electric servo mechanisms. All the feedback signals that come from the servo mechanisms are actually monitored by the servo drives. A servo drive continuously adjusts even the smallest deviation from the normal behavior.

It should be known that the main function of a servo drive is to receive the command signals from the control system and then amplify it so as to transmit the electric current to the servo motor. This is done to produce motion that is proportional to command signal. In general, the command signal signifies a preferred velocity but it can also signify a desired torque if and when required. 

The servo drive gets the feedback of the actual status of servo motor control from the servo motor’s attached sensor. The actual status of the motor is then compared with the commanded motor status by the servo drive. The servo drive alters the voltage frequency of the motor in order to correct any small deviation from the desired commanded status. 

The servo motor control rotates at a speed which closely matches the velocity signal that is being received from the control system by the servo drive. There are several parameters like derivative gain, proportional gain and feedback requires proper adjustment so as to achieve the desired performance. This process of adjusting of the parameters is known as performance tuning.   
     

With the advancement in the technology of the microprocessor units there has been a constant growth of cost effective solution and development of a permanent magnet manufacturing technology for the servo motors. There has been a great improvement in the technological development of the high performance and high power semi conductor power devices. Thus, AC servo drives, AC servo motor has now become the basic technology for achieving automation control system in the present industrial scenario. 

AC servo drivers bring in the newest high speed DSP in order to meet the varied requirements of your high speed and high precision control system. The latest AC servo drives have a lot better dynamic feature and stability that the convention PI controls systems of yester years.  

Today’s AC Servo drives includes analogue apparatus within the control loop of a servo motor that helps to minimize the energy consumption and ensures maximum output. They assist in changing frequency of the AC voltage which is received by the motor with the use of electronic devices.

Functions of motion control

Motion control can be said as one of the sub categories in the field of automation. When we work with machines in the field of automation we need to control a lot of parameters of the pump in order to get the desired results so the motion control can be done with the connection of some kind of pump in the motor which can also be a servo. Motion control is a simple thing when we work with simple machines. These are also used in the robotics and the CNC systems were the operation of the same thing is very complex. This is because of the kind of machines involved in both the processes. When we talk about the packaging industries and the textile industries and the assembly industries we understand how wide the scope of the same thing is. The motion control systems are gaining importance today.

The function of the motion control is vast and is not limited. Hence most of the people want to go with the motion control of the machines in order to be satisfied with the result it gives. The first and the most important and the well known function are the control of velocity by the motion control. There after it also can control the velocity and the pressure in other words. So if the motion control is attached to the machines getting the desired results is very important. These are particularly effective when the experiments are carried on. The reason is that one cannot have several different types of machines at the very initial stage. The motion control mechanism proves to be very effective and non expensive way to control motion of the machines in order to get the results as desired. The motion control is also used to control the position also. The position control of the motion control is mainly used in the control of the profiles like the trajectory ones.

The overview of the motion control is very complex. But it’s not very difficult to operate. People find these options very convenient and hence opt for the motion control when they have to control the output. If the input signal is good then the output is the best one can accept and this is the reason that people go for the motion control. The functions are vast and in many kinds of industry too. So the people can get one as per the desire of the people as such.

Working of the servo system

When we talk about the servo system and there functions we know that it is to convert the mechanical motion into a higher and an amplified version of the same kind of motion or the energy. When there is a need to enhance the frequency or the velocity which is again a type of the mechanical motion the work of the servo systems come into being and it is to amplify it. The servo systems are used a lot these days because these have a list of advantages linked to it. The servo systems are known to give high performance rates and also work with a high precision which is great. These are some of the reasons that man today prefers to use the servo systems. Today there are much different kind of models available in the market. The best of the servo systems look the best. These are very small and compact in size but when we talk about the performance of these there is nothing which can beat these. These prove themselves to be very efficient in the work of amplification.

Most of the servo systems these days are the choice of the customers. These are made just the way the customers want it. The basic and the common work of the servo system are kept the same and there are changes which are incorporated in the system as per the needs of the customers. The best feature of the servo system is that these are very friendly to the user and the desired performance can be achieved just by tuning the system well as per the need of the people. These have high efficiency also. There are synchronizations and the gearing option which is also inbuilt makes the efficiency of the output even more. There are temperature control sensors which are mounted on the servo systems. It regulates the temperature. If there is a rise in temperature above the standard point, then it should be controlled because it affects the optimum efficiency of the servo systems.

The servo system is insulated and hence people are happy because the chances of accidents are also less. Some of the features are so great that the servo systems are must wanted by the customers. A servo system is the one people prefer over the other kinds of amplification unit. The standard features are very good and some of the additional features are built by the makers as and when the user demands.

Importance of Motion Control in Industrial Applications

In industrial applications, machines are the most important part. The efficiency of the machines lies on its control and the administration of the motion control system. The man function of the motion control system is to control the machines movement. WE can otherwise represent the importance of the control system by saying that they are responsible for controlling the heart beat of the motors. This is the reason why the motion controls for various machines vary as per their applications. For example the motion control system of a ball screw machine system will not produce accurate and precise results when applied to a motor driven tool.

In the normal working of the conventional servo drive system, the motion controller sends electrical pulse signals to the motor. The Servo motor uses a glass scale or rotary encoder to verify the motion and catch error signals. In case no error signals are identified, the encoder placed in the servo system sends back confirmation pulse signals to the motion controller to confirm the utilization of the motion command. In case the tool has glass scales incorporated in to the axis then positioning of the axis in the scale also needs to be verified. For this a signal is again sent from the motion control to the glass scale for the proper positioning of the axis. This is how a motion control system offers extensive accuracy without the backlash of the components of the servo system.

When a machine tool gets calibrated, the motion control checks the value that is entered to check the pitch errors as depicted by the encoders and the amplifiers. These errors occur when the input signals sent do not match the existing processing or motion of the unit. The motion controller has to play a major role in rectifying the error and check the value of the parameters to ensure the production of accurate movement. This is the reason why overshoot or undershoot of the tool is prevented from happening when the machine is moved to a high speed rate. 

A motion control system remains incorporated in almost all servo systems. They not only play an important role in controlling the motion of the machine tools but also prevent damage due to excessive load. By working on the action signals sent to it by the encoder, the controller works on it to ascertain if any error has taken place and accordingly commands the movement of the servo motor. In short it helps in decreasing the power consumption of the machine while increasing its efficiency.

Servo Amplifier

A servo amplifier is a part of the closed loop servo control drive system is designed to primarily control the performance of a mechanism. Basically they are four-quadrant, power amplifiers with regenerative features and equipped to supply power according to the control voltage to the overall motor. These servo amplifiers can supply energy to the load, as well as absorb energy from the load. They are also designed to convert the kinetic energy of the combined motor load into electrical energy while the load is decelerating.

The output of a servo amplifier is an analogue circuit. The circuit enables the current and voltage of the motor to be adjusted to control position, torque and velocity. The feedback and comparator stages though can have a mixture of analog and digital devices.

Few ideal characteristics that are desired in a servo amplifier are as follows:

• Constant Velocity – ability to maintain the commanded velocity. Tachometers are used to record the aberrations between the commanded and actual motor speed.

·         Infinite Acceleration – an ideal amplifier must be able to provide infinite acceleration which can be observed by abruptly starting and stopping the motor.

·         Linear response – the amplifier need to respond proportionally to the changes in the velocity input command.

·         Hold Position – the amplifier should drive the motor in such a way that the latter holds its position irrespective of any external force or disturbance.

·         Overload protection – a low resistance circuit should be there to protect the amplifier from excessive current.

There are a host of servo amplifiers in the market but one should be careful while choosing an amplifier. The compatibility of the servo amplifier with its servo is to be ensured. Some notable types of servo amplifiers are as follows:

• Push Pull amplifiers – one of the earliest designs of amplifiers designed primarily for two transistors to get switched on/off to share the current load for the motor.
• Chopper amplifier – another primitive DC-motor based amplifier that finds limited usage today.
• L Type (Linear Motion) Servo Amplifier – it is fitted with linear positioning function you can basically construct a linear positioning system using such amplifiers as a ball screw or rack & pinion.
• Digital Amplifier – it is usually used for higher machine performance as it promises improved reliability and repeatability through digital technology.
• R Type (Rotation) Servo Amplifier – it provides an additional rotation angle indexing function. Rotation angle index system can be constructed using this amplifier.
• DC servo amplifier – both brush and brushless amplifiers can be found in simple DC motors

Brushless Servo Drives

Brushless servo drives are automatic instruments that monitor the performance of any mechanism based on the continuous feedback that it receives. Basically, it is a closed loop mechanism that sends rectification signals if the performance of the machine / instrument is deviating from the commanded data. Now, the instrument that really monitors the performance is called the servo drive. It is just an electronic amplifier that gets linked to a servo mechanism to monitor its performance. Servo drives can be brushed or brushless. While brushed motors provide exchange via physical contacts, brushless motors provide electronic exchange without physical contact, with the help of sinusoidal or the trapezoidal drives. These trapezoidal drives can energize two motor windings simultaneously before proceeding to the next pair of windings. Sinusoidal servo drives, on the other hand, can provide do this to three motor windings simultaneously with the sinusoidal signals.

Brushless motors work quite like AC motors where the rotor movement is caused by a dynamic magnet field. Brushless motors are known to have predicable linear characteristics. Brushless servo drives are AC or DC types. It is basically the way the motor is powered gives it the name AC or DC.

Read more about ac servo drives.

Torque developed by brushless servo drives depends on the control technology used. Type of control is determined by the feedback scheme exercised. DC motors use Hall sensors for feedback, whereas AC motors use resolver or encoder for feedback. Speed accuracy is very high in fact with the more popular brushless drive, almost close to 0%. This is due to the presence of a digital encoder and the drive controller regulation of position. High torque to inertia ratios provides high acceleration and deceleration rates with dynamic response.  Controller bandwidth is almost 8 times higher than the Brush DC drive. The Brushless DC motors have good thermal characteristics too. Motor efficiencies range anywhere around 90-96 % and controller efficiency around 97% giving overall efficiencies far superior than brush DC systems.

The benefits of brushless servo drives are:

• Very precise average speed control over a very wide speed range
• High dynamic response ensuring precise instantaneous speed control
• Constant power factor meaning lowest possible input current
• Smaller in size than the brush type
• No regular motor maintenance is needed
• Feedback device (encoder) is fitted internally and thereby less subject to errors
• Higher overall efficiency

Brushless servo drives find their usage in CNC machines, blowmolding and a host of other industrial applications -

Understanding Motion Control Drives

Motion control is a term that describes a range of applications that involve movement in specific routes designed to precision performance. Earlier motion control applications require only an object to be moved from one place to another without paying too much heed to speed or change of motion. On the other hand, there are machine tool applications which require the exact coordination of all aspects of motion, including a high degree of synchronization for multiple simultaneous movements.

Motion control drives finds heavy usage in the robotics industry. Motion control drives are known to monitor the motion performance of the mechanism. The feedback and the subsequent rectification, if needed, makes it ideally placed to be used in the robotics field. These drives are connected to motors that can be AC or DC. Further categorization can be made of DC brushed, DC brushless, AC Induction, AC synchronization and Stepper.

The motor amplifier or servo drive is designed to takes commands from the motion controller. These signals are incorporated in the analogue version where the voltage with low current is converted to high current signals in order to drive the motor. Motor drives come in many various types and makes and are fitted when matched to a specific motor they need to run. Along with matching the motor technology, the drive needs to ensure a balance of voltage, a continuous current and the balanced correct peak current.

The feedback of the mechanism’s performance can be taken of different parameters like back EMF, current, velocity, acceleration, position and many more. It’s because the control of these parameters will ensure the overall control of the motion of the object. Some of the sources for these feedbacks are:

• Hall effect sensors
• Encoder
• Potentiometer
• Tachometer
• Acceleration specific sensor

A motion control drive’s range of applications is far more specialized than any other manufacturing applications. Motion control drives must be capable of:

• Zero-speed holding torque
• Quick start/stop cycles
• Repeatable velocity and torque profiles
• High accelerating torque
• Synchronization
• Precise speed control
• Positioning capabilities

Motion control can operate two levels – the linear or the rotational axis. A linear axis application like a vehicle in motion has a pre-defined traversing range with predefined end stops. The rotational axis has a vast and almost never-ending traversing range when applied. A rotary table on the other hand travels a pre-defined yet short distance. They have a selected path or direction for moving point to point.