控制术语表
- bang-bang control
A very simple, no-tuning-required closed-loop control technique. It simply “turns on” the control effort when the process variable is too small, and “turns off” the control effort when the process variable is too big. It works well in some cases, but not all. See “Bang-bang” control on Wikipedia for more info.
- Cartesian coordinate system
A set of points in space where each point is described by a set of numbers, indicating its coordinates within that space. These coordinates are an expression of the orthogonal distance of each point from a set of fixed, orthogonal axes (IE, a “rectangular” system). 2-dimension and 3-dimension spaces are most common in FRC (and likely what was learned in algebra 1), but any number of dimensions is theoretically possible. See Cartesian coordinate system on Wikipedia for more info.
- churning losses
Complex friction-like forces arising from the fact that when gears and bearings rotate, they must displace liquid lubricant. This reduces the efficiency of rotating mechanisms.
- control signal
The driving signal sent to a plant by a controller, usually quantified as a voltage.
- 控制工作
- 控制律
一种数学公式，在给定当前状态的情况下，产生 inputs 1 来驱动 system`达到期望的 :term:`state。一个常见的例子是控制律:math:mathbf{u} = mathbf{K(r - x)}
- controller
与:术语:“装置”一起用于位置或负反馈，通过驱动:术语:“参考”信号和:术语:“输出”之间的差值到零，从而达到所期望的:术语:“系统状态”。
- convolution
A mathematical operation that calculates a weighted moving average of one function, with the weights assigned by a second function. A common way to “filter” sensor input is to apply a convolution to it, using a carefully-chosen filtering function. See convolution on Wikipedia for more info.
- counter-electromotive force
A voltage generated in a spinning motor. The voltage is a result of the fact that has a coil of wire rotating near a magnet. See Counter-electromotive_force on Wikipedia for more info.
- current
The flow of electrons through a conductor. Current is described with a unit of “Amps” (or simply “A”), and is measured at a single point in a circuit. One amp is equal to \(6241509074000000000\) electrons moving past the measurement point in one second.
- 动力学
物理学的一个分支，涉及在力作用下物体的运动。在现代控制中，系统根据其动态发展。
- derivative
A mathematical operation which evaluates the “rate-of-change” of a function at a given point. See derivative on Wikipedia for more info.
- 错误
Reference 1 减去: term:output`或 :term:`state.
- exponential search
An iterative process of finding a specific value within a wide search range by applying a multiplicative factor to the search value. See exponential search on Wikipedia for more info.
- exponential smoothing
A very common way to implement a simple low-pass filter, using an exponential window function in a convolution with an input signal. The convolution operation simplifies down to a very simple set of math operations on the current input and previous output. See exponential smoothing on Wikipedia for more info.
- 增益
A scalar value that relates the magnitude of an input signal to the magnitude of an output signal. For example,
gaininoutput = gain * input. A gain greater than one would amplify an input signal, while a gain less than one would dampen an input signal. A negative gain would negate the input signal.- Gaussian distribution
A special mathematical function that describes distributions of averages. The graph of a Gaussian function is a “bell curve” shape. This function is described by its mean (the location of the “peak” of the bell curve) and variance (a measure of how “spread out” the bell curve is). See Gaussian distribution on Wikipedia for more info.
- gradient
The derivative, but applied to a function with multiple inputs. As a result, the output is both the magnitude of the rate of change, and the vector direction along which it occurs.
- 输入
- An input to the plant (hence the name) that can be used to change the plant’s state.
例如：飞轮有1个输入：驱动它的电动机电压。
例如：动力传动系统可能有2个输入：左右电动机的电压。
输入通常用变量 \(\mathbf{u}\), 表示，这是一个列向量，每个输入对system都具有一个输入。
- least-squares regression
A curve-fitting technique which picks a curve to minimize the square of the error between the fitted curve and the actual measured data. See ordinary least-squares regression on Wikipedia for more info.
- LQR
Linear-Quadratic Regulator - A feedback control scheme which seeks to operate a system in a “most optimal” or “lowest cost” manner, in the sense of minimizing the square of some “cost function” that represents a combination of system error and control effort. This requires an accurate mathematical model of the system being controlled, and function describing the “cost” of any given system state. See LQR on Wikipedia for more info.
- 测量
测量是用传感器从 plant`或物理系统测量的:term:`outputs 1 。
- 模型
A set of mathematical equations that reflects some aspect of a physical system's behavior.
- 观察者
在控制理论中，一种系统，通过测量一个给定实体的“输入”和“输出”来估计其内部的状态。WPILib包括一个用于观察线性系统的卡尔曼滤波器类，以及用于非线性系统的扩展卡尔曼滤波器类和非scentedkalmanfilter类。
- orthogonal
Having the property of being independent, or lacking mutual influence. For example, two lines are orthogonal if moving any number of units along one line causes zero displacement along the other line. In a cartesian coordinate system, orthogonal lines are often said to have 90-degree angles between each other.
- output
- Measurements from sensors. There can be more measurements than states. These outputs are used in the “correct” step of Kalman Filters.
例如：飞轮可能用:term:`output`输出1来表示其速度。
例如：动力传动系统可能使用solvePNP和V-SLAM在野外找到其x / y /航向位置。可以进行6种测量（solvePNP x / y / heading和V-SLAM x / y / heading）和3种状态（robot x / y / heading）。
Outputs of a system are often represented using the variable \(\mathbf{y}\), a column vector with one entry per output (or thing we can measure). For example, if our system had states for velocity and acceleration but our sensor could only measure velocity, our output vector would only include the system's velocity.
- phase portrait
A graph of a function’s value and its derivative as they change in time, given some initial starting conditions. They are useful for analyzing system behavior (stable/unstable operating points, limit cycles, etc.) given a certain set of parameters or starting conditions. See phase portrait on Wikipedia for more info.
- PID
Proportional-Integral-Derivative - A feedback controller which calculates a control signal from a weighted sum of the error, the rate of change of the error, and an accumulated sum of previous errors. See PID controller on Wikipedia for more info.
- 设备
术语:被控制的执行机构的“系统”或集合。
- 过程变量
该术语用于描述PID控制环境下的 plant 的输出。
- r-squared
A statistical measurement of how well a model predicts a set of data, representing the fraction of the observed variation in the independent variable that is accurately predicted by the model. The value typically runs from 0.0 (a terrible fit, equivalent to just guessing the average value of your independent variable) to 1.0 (a perfect fit). See Coefficient_of_determination on Wikipedia for more info.
- 参考
期望的状态。这个值用作控制器误差计算的参考点。
- 上升时间
在应用:term:step input`后，:term:`system 最初到达 reference 所需的时间。
- RMSE
Root Mean Squared Error - Statistical measurement of how well a curve is fit to a set of data. It is calculated as the square root of the average (mean) of the squares of all the errors between the actual sample and the curve fit. It has units of the original input data. See Root Mean Squared Error on Wikipedia for more info.
- 设定点
该术语用于描述PID控制器的 reference 。
- 沉淀时间
:term:`system`在:term:`step input`后的:term:`reference`处设置所需的时间。
- signum function
A non-continuous function that expresses the “sign” of its input. It is equal to -1 for all negative input numbers, 0 for an input of 0, and 1 for all positive input numbers. See signum function on Wikipedia for more info.
- 状态
- A characteristic of a system (e.g., velocity) that can be used to determine the system's future behavior. In state-space notation, the state of a system is written as a column vector describing its position in state-space.
Ex. A drivetrain system might have the states \(\begin{bmatrix}x \\ y \\ \theta \end{bmatrix}\) to describe its position on the field.
例如：抬升系统可能具有以下状态： \(\begin{bmatrix} \text{position} \\ \text{velocity} \end{bmatrix}\) 来描述其当前的高度和速度。
A system's state is often represented by the variable \(\mathbf{x}\), a column vector with one entry per state.
- statistically robust
The property of a data processing algorithm which makes it resilient to a noisy or outlier-prone data set. Designing statistically robust algorithms on robots is important because real-world sensor data can often be unpredictable, but unexpected robot behavior is never desirable. See Robust Statistics on Wikipedia for more info.
- 稳态误差
- 阶跃输入
A:term: ‘ system ‘:term: ‘ input ‘即:math: ‘ 0 ‘ for:math: ‘ t <和一个大于:math: ‘ 0 ‘的常数:math: ‘ t geq 0 ‘。对于:math: ‘ t geq 0 ‘， step input为:math: ‘ 1 ‘，称为单位阶跃输入。
- 阶跃响应
The response of a system to a step input.
- 系统
A term encompassing a plant and its interaction with a controller and observer, which are treated as a single entity. Mathematically speaking, a system maps inputs to outputs through a linear combination of states.
- 系统识别
The process of capturing a system's dynamics in a mathematical model using measured data. The SysId toolsuite uses system identification to find kS, kV, and kA terms.
- 系统反应
对于给定的：term：input，：term：`system`随时间的行为。
- voltage
The measurement of how much an electric field is “pushing” electrons through a circuit. It is sometimes called “Electromotive Force”, or “EMF”. It is measured in units of “Volts”. It always is defined between two points in a circuit. If one electron travels between two points that have one volt of EMF between them, it will have been accelerated to the point of having \(\frac{1}{6241509074000000000}\) joules of energy.
- viscous drag
The force generated from an object moving relatively slowly through non-turbulent fluid. In this region, the force is roughly proportional to the velocity of the object. It describes the most common type of “air resistance” an FRC robot would encounter, as well as losses in a gearbox from displacing grease. See Drag (physics) on Wikipedia for more info.
- x-dot
\(\dot{\mathbf{x}}\), 或者x-dot: state`向量 :math:mathbf{x}`的导数，如果term:system 只有一个速度:term:state，那么:math:`dot{mathbf{x}}`表示系统的加速度。
- x-hat
\(\hat{\mathbf{x}}\), 或者 x-hat: 由:term:observer`估计的系统估计 :term:`state 。