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1. Feedback Control System :
Feedback control system is basically a control system where the output depends on the generated feedback
signal. Feedback control system is responsible for processing the feedback signals which further act as an input to the system. Feedback control system consist of different components such as resistors, transistors and other electrical appliances which do the basic functioning. The feedback can further be divided into positive feedback and negative feedback.
2. Feed forward Control System :
Feed forward control system is a system which passes the signal to some external load. It
rejects the disturbances before they affect the controlled variable. It controls the major disturbances and is many times used with the combination of a feedback system. Feed forward systems are sensitive to modelling errors. It does direct measurement of the disturbances in the system.
Difference between Feedback and Feed Forward Control Systems :
| 1. | In feedback system output depends on the generated feedback signal. | In feed forward system the signal is passed to some external load. |
| 2. | Measure of disturbances in the system is not needed by feedback system. | Measure of disturbances in the system is needed by feedback system. |
| 3. | All the disturbances are detected in feedback system. | All the disturbances are not detected in feedback system. |
| 4. | The loop in a feedback system is a closed loop. | The loop in a feedback system is a open loop. |
| 5. | It focuses on the output of the system. | It focuses on the input of the system. |
| 6. | The variables are adjusted on the basis of errors. | The variables are adjusted on the basis of knowledge. |
Feed-forward, concurrent and feedback types of control
Controlling is the basic management function of establishing benchmarks, comparing actual performance against established standards and taking corrective action, if required. Controlling is the responsibility of managers at all levels in an organization. Controlling is needed because of the changing environment, complexity of tasks, mistakes and problem delegation.
The three types of controlling [feed-forward, concurrent and feedback] can be explained as follow;
i- Feed-forward control is also called preventive control. It is done at the input level of production. It set off before the beginning of production or service activity. The rationale of feed-forward control is to foresee potential problems and prevent them from occurring. Its main objective is to prevent problems at the input levels before going through the transformation process. The example of feed-forward control is the specifications of qualification as investor of Lembaga Tabung Haji. Differ from any other financial institution, Lembaga Tabung Haji declared that only Muslim investors are allowed to open a saving account or participate in share investment activities. This is to ensure the share and returns obtained are halal and toyyiban.
ii- Concurrent Control is also known as steering control as it focus on what arises during the work process. Concurrent control can identify problems as they develop and take immediate corrective action before final results are attained. As an example, product manufacturing departments are responsible to measure the items being produced meet quality standards. If there are wrecked products or the products being produced doesn’t meet the standards acquired, the manufacturing staff will report to the manager to let the manager know that a problem is occurring.
iii- Feedback Control is the act of controlling takes place after a process is complete. It is also known as Post Action Control. It attempts to measure the result of certain actions. If problems exist, corrective action is undertaken. The example of feed-back control is when customer service department obtained complaints on the poor services provided by the customer service officers, the manager will study the cause and draw new service delivery plan to ensure better customer service in the future.