Automation basics: The term automation is derived from the Greek root words of ‘Auto’, meaning “self”, and ‘Matos’, meaning “moving”. So, automation can be described as a mechanism that has the ability to move by itself. Automated systems tend to achieve significantly superior performance to manual systems, specifically in terms of power, precision and speed.
Automation, the application of machines to tasks once performed by human beings or, increasingly, to tasks that would otherwise be impossible. Although the term mechanization is often used to refer to the simple replacement of human labor by machines, automation generally implies the integration of machines into a self-governing system
Encyclopedia Britannica, Mikell P. Groover
Automation can also be defined as the use of technology for performing a process with the help of programming commands in combination with a ‘feedback control system’, ensuring an error-free execution of the given commands. The resulting system would have the ability to operate without any human participation.
Automation basics – 3 different types of Automation
Automation can be classified into three forms:
- Fixed Automation – To automate a fixed sequence of operations with the help of special purpose equipment. The product design is inflexible and the production rates are high. (Mass Production)
- Programmable Automation – The equipment is designed to accommodate some specific changes, meaning the product design is somewhat flexible. Production is done in batches and the production volume is medium. (Batch Production)
- Flexible Automation – General purpose equipment is used in order to accommodate variety in product design. The production rate is low and so is the volume. (Job-shop Production)
The control system is considered the kernel of automation. It is a system of devices that manages, commands, directs and regulates the behavior of all the other systems and devices.
The main feature of a control system is a mathematical relationship between the input and output. If the relationship between the input and output is linear, the resulting system is a linear-control system. Similarly, if the relationship is non-linear, the resulting system is called a non-linear control system.
Requirements of a Good Control System
Like any system, a control system has its defined KPIs (Key Performance Indicators). These KPIs are commonly related to the following metrics:
- Sensitivity: The parameters of a system are subject to continuous change because of the influence of surrounding environments, internal conditions, and other influences. Such a change is determined in terms of sensitivity. A system should be sensitive to changes in input signal.
- Noise: Any undesired signal is referred to as noise. A good control system should have the ability to ignore noise in order to focus on the desired signal.
- Accuracy: This can be defined as the tolerance of the instrument and limits of error in the equipment under standard operating conditions. Feedback elements can be incorporated in the system to increase the accuracy of the output.
Types of Control Systems
There are different types of control systems, but all are intended to control the output. These following types are the most common:
- Discrete Control: This is the simplest form of control system and can be seen in most household appliances in the form of on/off A good example is a thermostat used in household appliances, which makes use of sensors to turn the heating/cooling mechanism on and off when the desired temperature is reached.
- Continuous Control: This is a kind of control system in which change in one variable is translated into a change in another variable. For example; if variable A is related proportionally to variable B, then an incremental change in A would be translated in an subsequent change in B and vice versa.
- Open/Closed Loop: If a control system makes use of the output signal, compares it with a set-point, calculates error, and makes re-adjustments then the system is called closed loop. But if the system makes no such comparisons and gives the output signal straightaway without any re-adjustments then such a system is called open loop.
Advantages and Disadvantages
|Increased productivity||Susceptible to errors outside immediate scope of knowledge|
|Increased quality and predictability||Large research & development costs|
|Reduced labor costs and human participation||High setup/initial costs|
Limitations to Automation
Despite advances in automation technology there are still some limitations:
- Not all processes and tasks can be automated. Some are simply too complex or variable for a machine to handle.
- Automation often requires high capital costs, surpassing the monetary benefit resulting from automation.
- Malfunctions in automated systems can be extremely hazardous, so the need for human supervision cannot be eliminated altogether.
- As more processes continue to be automated, fewer non-automated processes remain which results in opportunity-exhaustion.
If an automated system has an error, it will multiply that error until it’s fixed or shut down. This is where human operators come in.
Josh Kaufman – The Personal MBA on the Paradox of Automation
Reasons for Automation
There are several common motivations behind automating a process:
- Reduced MLT (Manufacturing Lead Time).
- Lower expenses, lower scrap rates, superior quality and low WIP (Work in Process).
- Increased Productivity.
- Reduced Labor and labor cost.
Reasons for not Automating
There are also several reasons that lead companies to not automate:
- Labor resistance (labor unions, strikes, etc.)
- Highly-skilled labor requirements (re-training time and cost).
- Initial capital investment is high.
Automation has clear benefits in many situations…lower production costs and higher productivity and quality. However, it’s not a solution for every situation. A company must investigate the financial costs and trade-offs, the impact to the workforce, and the technical requirements for an automated process to pay off.