It works control system and its composition
Works 1.1
Control system, also called the system a given amount of input , the control amount is also known as the system output .
Output return process is called feedback , which indicates the amount of output by the measuring device to return all or a portion of the input terminal, and compared with the input signal, the comparison result is called bias .
Works control system are summarized as follows:
- The actual value of the detection output.
- The actual value obtained is compared with the given deviation value (input).
- Generating a control value by regulation to eliminate bias deviation.
Based on this feedback principle, the "re-correct the deviation detecting deviation" of the system is called a feedback control system .
Visual feedback control system should have at least the measurement , comparing (or calculated), and performs three basic functions.
1.2 open-loop control and closed-loop control
The actual control system, feedback can be divided according to whether the open-loop control , closed-loop control system and a semi-closed loop control system categories.
1. The open loop control system
The system only based on input and control the amount of interference, and between the output and the input of the absence of a feedback loop , the control output of the system does not have any impact on the overall control process.
If for some interference of the output deviation amount of the original value, it does not automatically correcting capability , to compensate, then the aid must be changed manually input.
Open-loop system of low control precision , the advantage of a simple system .
2. closed loop control system
Between the system output and the input of the presence of a feedback loop , the output of a direct impact on the control process.
The role of feedback loop is applied to reduce bias, and therefore, the feedback control system must be a closed loop control system .
The advantage of high precision control , but since the entire control process there is always a deviation due to the inertia element, if the configuration parameters properly, it is easy to cause turbulence , to make the system unstable , does not work, i.e., must coordinate accuracy and stability.
3. The semi-closed loop control system
The feedback signal is not drawn directly from the output end of the system, but indirectly from the middle of the measuring element.
Between the control accuracy in front of the two control systems, a closed loop system is more than easy to implement the system stable .
Closed loop control system consisting of 1.3
2 basic types of control systems
2.1 classified according to characteristics of the input amounts
2.2 Properties of classification signal transmitted by the system
Continuous control system differential equations to describe the system in motion, and is Laplace transform method for solving differential equations;
Discrete control system differential equations to describe the motion state of the system, using Z transform extraction pulse transfer function to study the dynamics of the system.
The basic control system of claim 3
