A1.3 · Computer fundamentals · HL
A1.3 · 计算机基础 · HL
Control System Components
控制系统的组成部件
A thermostat, a cruise control and an automatic door all work the same way: measure the current state, compare it with a target, and act to close the gap, then measure again. That loop is a control system.
恒温器、定速巡航和自动门的工作方式都一样:测量当前状态,与目标比较,采取行动弥合差距,然后再次测量。这个回路就是一个控制系统。
Explainer
讲解
The input, process, output, feedback model
输入、处理、输出、反馈模型
A control system is a set of components that manages or regulates the behaviour of a device or process. It is built around the input, process, output model with a feedback mechanism.
控制系统是一组管理或调节某个设备或过程行为的部件。它围绕输入、处理、输出模型,并带有一个反馈机制。
Input is the target the system should reach (a set temperature, a desired speed) together with readings from sensors about the current state. Process is the controller comparing the target with the readings, finding the error, and running its control algorithm to decide what to do. Output is the physical action an actuator takes, and the change that action makes to what the system is doing.
输入是系统应达到的目标(设定的温度、期望的速度),连同传感器给出的关于当前状态的读数。处理是控制器把目标与读数相比较,求出误差,并运行其控制算法来决定该做什么。输出是执行器采取的物理动作,以及这个动作让系统状态发生的改变。
Explainer
讲解
Open-loop and closed-loop
开环与闭环
| Open-loop | Closed-loop | |
|---|---|---|
| Feedback | None: the system acts on the input alone | The output is measured and fed back to adjust the process |
| Behaviour | Runs a fixed sequence regardless of the result | Continuously corrects the error between target and actual state |
| Suits | Simple, predictable tasks (a timer-controlled toaster, sprinklers on a clock) | Tasks needing accuracy under changing conditions (a thermostat, cruise control) |
| 开环 | 闭环 | |
|---|---|---|
| 反馈 | 没有:系统只依据输入行动 | 测量输出并反馈,以调整处理过程 |
| 行为 | 无论结果如何都运行一个固定的序列 | 持续修正目标与实际状态之间的误差 |
| 适合 | 简单、可预测的任务(定时控制的烤面包机、按时钟运行的喷灌) | 在变化条件下需要精度的任务(恒温器、定速巡航) |
Closed-loop control works because the output is measured and compared back against the target. The difference is the error, and the controller keeps acting to drive that error towards zero.
闭环控制之所以有效,是因为输出会被测量并与目标相比较。两者之差就是误差,控制器不断行动,把这个误差驱向零。
Explore
探索
The five components
五个组成部件
Click each component to see what it does and a concrete example in a real control system.
点击每个部件,看看它做什么,以及在真实控制系统中的一个具体例子。
Check your understanding
检验你的理解
In a control system, which component converts the controller’s signal into a physical action?
在控制系统中,哪个部件把控制器的信号转换成物理动作?
Common mistake
常见错误
RecurringWeak answers list the components (“a control system has sensors, a controller and actuators”) and stop. Describe here means say how they work together in the feedback loop: the sensor measures the current state, the controller compares it with the target and runs the control algorithm to find the correction, the actuator applies that correction, and the sensor measures again, closing the loop. Also keep sensor and transducer distinct: a sensor detects a physical quantity; a transducer changes a signal from one form into another.
反复出现薄弱的答案罗列部件(“控制系统有传感器、控制器和执行器”)就停了。这里的 describe(描述) 指的是说明它们在反馈回路中如何协同:传感器测量当前状态,控制器把它与目标比较并运行控制算法求出修正量,执行器施加这个修正,然后传感器再次测量,闭合回路。另外要把传感器和换能器区分开:传感器检测某个物理量;换能器把信号从一种形式改成另一种形式。
List, no interaction: “A control system is made of sensors, a controller, actuators and a control algorithm.” Names the parts but never says how one feeds the next.
只罗列,无互动: “控制系统由传感器、控制器、执行器和控制算法组成。”点出了部件,却从没说一个如何馈送给下一个。
Components in the loop: “A temperature sensor reports the current room temperature to the controller. The controller compares it with the set point, and its control algorithm calculates how much heating is needed to close the gap. It signals the actuator, a relay that switches the heater on. As the room warms, the sensor keeps reporting, so when the temperature reaches the target the controller switches the heater off. This closed loop keeps correcting the error.”
回路中的部件: “温度传感器把当前室温报告给控制器。控制器把它与设定值比较,其控制算法算出需要多少加热才能弥合差距。它给执行器发信号,执行器是一个把加热器接通的继电器。随着房间变暖,传感器持续报告,于是当温度达到目标时,控制器把加热器关闭。这个闭环不断修正误差。”
Revision questions
复习题
Specimen-paper style. Write an answer, then reveal the marking points and mark yourself.
采用样卷风格。写下答案,然后展开评分要点给自己打分。
[4]Describe the input, process, output and feedback stages of a control system.
[4]描述控制系统的输入、处理、输出和反馈各阶段。
Marking points
评分要点
- Input: the target/desired value (a set temperature or speed) plus sensor readings of the current state.
- Process: the controller compares target with reading, finds the error, and runs the control algorithm to decide the correction.
- Output: the actuator performs a physical action, changing the system's actual state.
- Feedback: the new output is measured and sent back to the controller to compare again.
- 输入:目标 / 期望值(设定的温度或速度)加上传感器对当前状态的读数。
- 处理:控制器把目标与读数比较,求出误差,并运行控制算法决定修正量。
- 输出:执行器执行物理动作,改变系统的实际状态。
- 反馈:新的输出被测量并送回控制器再次比较。
[4]Describe the difference between an open-loop and a closed-loop control system, with an example of each.
[4]描述开环控制系统与闭环控制系统的区别,并各举一个例子。
Marking points
评分要点
- Open-loop: acts on the input alone, no feedback; runs a fixed sequence regardless of the result. Example: a timer-controlled toaster or sprinklers on a clock.
- Closed-loop: measures the output and feeds it back to correct the error between target and actual. Example: a thermostat or cruise control.
- One example of each is required.
- 开环:只依据输入行动,没有反馈;无论结果如何都运行固定序列。例子:定时控制的烤面包机或按时钟运行的喷灌。
- 闭环:测量输出并反馈,以修正目标与实际之间的误差。例子:恒温器或定速巡航。
- 每种需要一个例子。
[4]Describe what the controller, the sensors and the actuators each do, and how one hands work to the next.
[4]描述控制器、传感器和执行器各自做什么,以及一个如何把工作交给下一个。
Marking points
评分要点
- Sensor: measures a physical quantity (temperature, position) and sends it to the controller as feedback.
- Controller: compares the reading with the target, runs the control algorithm to find the correction, and commands the actuator.
- Actuator: carries out the physical action the controller commands.
- Interaction: sensor -> controller -> actuator, then the sensor measures the new state, closing the loop.
- 传感器:测量物理量(温度、位置)并作为反馈发给控制器。
- 控制器:把读数与目标比较,运行控制算法求出修正量,并命令执行器。
- 执行器:执行控制器命令的物理动作。
- 相互作用:传感器 -> 控制器 -> 执行器,然后传感器测量新的状态,闭合回路。
[3]Describe what a transducer is for, with an example from a real control system.
[3]描述换能器的用途,并举一个来自真实控制系统的例子。
Marking points
评分要点
- A transducer converts one form of energy or signal into another.
- It sits between a sensor/actuator and the controller when their signal forms do not match.
- Example: a pressure transducer converts mechanical water pressure into an electrical signal the controller can read.
- 换能器把一种能量或信号形式转换成另一种。
- 当传感器 / 执行器与控制器的信号形式不匹配时,它位于两者之间。
- 例子:压力换能器把机械的水压转换成控制器能读取的电信号。
[3]Describe what job the control algorithm does inside a controller.
[3]描述控制算法在控制器内部承担什么工作。
Marking points
评分要点
- The control algorithm is the set of rules the controller uses to turn the error into an output.
- It can be simple on/off logic, or a method like PID that weighs the error now, its build-up over time and its rate of change.
- It determines how accurately and stably the system reaches the target.
- 控制算法是控制器把误差转化为输出所使用的一组规则。
- 它可以是简单的开 / 关逻辑,或像 PID 那样综合考虑当前误差、随时间的累积和变化率的方法。
- 它决定系统达到目标的精度和稳定性。
Flashcards
记忆卡片
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