Frenet轨迹规划

可以帮我发一下Frenet坐标系下的动态轨迹规划的matlab代码吗,十分感谢。

参考GPT和自己的思路,Frenet坐标系下的动态轨迹规划需要根据具体的问题进行实现,这里提供一个基础的代码框架,供参考:

% Frenet Trajectory Planning

% Define the reference path
refPath = [0 0; 20 20; 40 10; 60 25; 80 10; 100 0];
s = linspace(0, 1, size(refPath, 1));
splineX = spline(s, refPath(:, 1));
splineY = spline(s, refPath(:, 2));

% Define the initial conditions
x0 = [0, 0, 0, 0, 0, 0];
tspan = [0, 5];

% Define the cost function
costFunction = @(x) frenetCost(x, splineX, splineY, s);

% Define the constraints
constraintFunction = @(x) frenetConstraints(x, splineX, splineY, s);

% Solve the optimization problem
options = optimoptions(@fmincon, 'Algorithm', 'interior-point', 'Display', 'iter');
[x, fval, exitflag] = fmincon(costFunction, x0, [], [], [], [], [], [], constraintFunction, options);

% Plot the results
plotFrenetTrajectory(x, splineX, splineY, s);

其中,refPath表示参考路径,splineX和splineY表示参考路径的样条插值函数。x0是初始状态,tspan表示时间范围。costFunction和constraintFunction分别表示代价函数和约束条件。使用fmincon函数求解优化问题,得到最优解x。最后使用plotFrenetTrajectory函数绘制Frenet轨迹。

具体实现时,需要根据问题进行修改和扩展。需要注意的是,Frenet坐标系下的动态轨迹规划需要考虑多种因素,如车辆动力学模型、障碍物避障、速度规划等,因此实现较为复杂。建议先从基础的静态轨迹规划开始学习,逐步增加复杂度。

该回答引用GPTᴼᴾᴱᴺᴬᴵ
这里提供一个基于Frenet坐标系的路径规划MATLAB代码示例,代码包括了路径生成、平滑和路径跟踪三个模块。具体实现过程中用到了cubic-spline插值和LQR控制器。以下是代码:

% Frenet-based dynamic trajectory planning and tracking

clc;
close all;
clear;

%% Path Generation

% Define reference path in Cartesian coordinate system
waypoints = [0 0; 30 20; 60 20; 70 10; 70 -10; 60 -20; 30 -20; 0 0];

% Convert reference path to Frenet coordinate system
[FrenetPath, FrenetFrame] = Cartesian2Frenet(waypoints);

% Generate path with desired speed profile
numPoints = 400;
maxSpeed = 10;
path = GeneratePath(FrenetPath, numPoints, maxSpeed);

%% Path Smoothing

% Cubic spline interpolation
path = CubicSpline(path);

%% Path Tracking

% LQR controller parameters
Q = diag([1, 1, 1, 1, 1]);
R = 0.1;

% Define initial state
x0 = [path(1,1); 0; 0; path(1,2); 0];

% Define time step
dt = 0.1;

% Define simulation time
simTime = 20;

% Path tracking simulation
[x, u] = PathTracking(path, x0, simTime, dt, Q, R);

%% Plot Results

% Plot reference path
figure;
plot(waypoints(:,1), waypoints(:,2), 'k--');
hold on;

% Plot smoothed path
plot(path(:,1), path(:,2), 'b');

% Plot path tracking simulation
plot(x(:,1), x(:,4), 'r');

legend('Reference Path', 'Smoothed Path', 'Path Tracking');
xlabel('X [m]');
ylabel('Y [m]');


其中 Cartesian2Frenet 函数将笛卡尔坐标系的路径转换为 Frenet 坐标系的路径,GeneratePath 函数在 Frenet 坐标系下生成速度剖面匹配的路径,CubicSpline 函数对路径进行三次样条插值,PathTracking 函数利用 LQR 控制器实现路径跟踪。注意代码中的各个函数的实现需要自己编写。

该回答引用ChatGPT

当涉及到动态轨迹规划时,常常使用Frenet坐标系。下面是一个简单的Matlab代码实现,用于计算和可视化Frenet坐标系下的轨迹规划:

% 定义路线的参数化函数
s = linspace(0, 10*pi, 1000);
x = s.*cos(s);
y = s.*sin(s);

% 计算Frenet坐标系下的参数化函数
[kappa, s] = curvature(x, y);
theta = atan2(y', x');
d = zeros(size(s));

for i = 2:length(s)
    dx = x(i) - x(i-1);
    dy = y(i) - y(i-1);
    d(i) = d(i-1) + norm([dx, dy]);
end

% 定义起点和终点
start = [x(1); y(1); theta(1); kappa(1); d(1)];
goal = [x(end); y(end); theta(end); kappa(end); d(end)];

% 使用Dijkstra算法进行路径规划
path = dijkstra(start, goal, @cost);

% 绘制结果
figure
plot(x, y, 'k', 'LineWidth', 2);
hold on
plot(path(:,1), path(:,2), 'r', 'LineWidth', 2);
axis equal
xlabel('X位置');
ylabel('Y位置');
title('Frenet坐标系下的轨迹规划');

% 定义成本函数
function c = cost(x1, x2)
    c = norm(x1(5) - x2(5)) + norm(x1(4) - x2(4))*10;
end

% 计算曲率
function [kappa, s] = curvature(x, y)
    dx = gradient(x);
    ddx = gradient(dx);
    dy = gradient(y);
    ddy = gradient(dy);
    kappa = (dx.*ddy - dy.*ddx)./((dx.^2 + dy.^2).^(3/2));
    s = zeros(size(x));
    for i = 2:length(x)
        ds = norm([dx(i); dy(i)]);
        s(i) = s(i-1) + ds;
    end
end

% Dijkstra算法
function path = dijkstra(start, goal, costfun)
    openSet = PriorityQueue();
    openSet.insert(start, 0);
    cameFrom = containers.Map();
    gScore = containers.Map();
    gScore(mat2str(start)) = 0;
    while ~openSet.isEmpty()
        current = openSet.remove();
        if isequal(current, goal)
            path = reconstructPath(cameFrom, current);
            return
        end
        neighbors = getNeighbors(current);
        for i = 1:size(neighbors, 1)
            neighbor = neighbors(i, :);
            tentativeGScore = gScore(mat2str(current)) + costfun(current, neighbor);
            if ~gScore.isKey(mat2str(neighbor)) || tentativeGScore < gScore(mat2str(neighbor))
                cameFrom(mat2str(neighbor)) = current;
                gScore(mat2str(neighbor)) = tentativeGScore;
                fScore = tentativeGScore;
                if ~openSet.contains(neighbor)
                    openSet.insert(neighbor, fScore);
                else
                    openSet.updatePriority(neighbor, fScore);
                end
            end
        end
    end
end

% 重构路径
function path = reconstructPath(cameFrom, current)
    path = current;
    while
cameFrom.isKey(mat2str(current))
    current = cameFrom(mat2str(current));
    path = [current; path];
end
end

% 获取邻居节点
function neighbors = getNeighbors(node)
x = node(1);
y = node(2);
theta = node(3);
kappa = node(4);
d = node(5);
L = 2;
delta = linspace(-pi/4, pi/4, 5);
neighbors = zeros(length(delta), 5);
for i = 1:length(delta)
deltaTheta = delta(i);
nextTheta = theta + kappaLtan(deltaTheta);
nextKappa = kappa + deltaTheta/L;
nextD = d + L/cos(deltaTheta);
neighbors(i,:) = [x+Lcos(nextTheta); y+Lsin(nextTheta); nextTheta; nextKappa; nextD];
end
end

% 优先队列
classdef PriorityQueue < handle
properties (Access = private)
heap
priority
count
end
methods
    function obj = PriorityQueue()
        obj.heap = cell(16, 1);
        obj.priority = zeros(16, 1);
        obj.count = 0;
    end
    
    function insert(obj, element, priority)
        obj.count = obj.count + 1;
        if obj.count > length(obj.heap)
            obj.heap = [obj.heap; cell(16, 1)];
            obj.priority = [obj.priority; zeros(16, 1)];
        end
        obj.heap{obj.count} = element;
        obj.priority(obj.count) = priority;
        obj.bubbleUp(obj.count);
    end
    
    function element = remove(obj)
        element = obj.heap{1};
        obj.heap{1} = obj.heap{obj.count};
        obj.priority(1) = obj.priority(obj.count);
        obj.count = obj.count - 1;
        obj.bubbleDown(1);
    end
    
    function empty = isEmpty(obj)
        empty = (obj.count == 0);
    end
    
    function updatePriority(obj, element, priority)
        index = find(cellfun(@(x)isequal(x, element), obj.heap), 1);
        obj.priority(index) = priority;
        obj.bubbleUp(index);
    end
    
    function containsElement = contains(obj, element)
        containsElement = any(cellfun(@(x)isequal(x, element), obj.heap));
    end
end

methods (Access = private)
    function bubbleUp(obj, index)
        if index == 1
            return
        end
        parent = floor(index/2);
        if obj.priority(index) < obj.priority(parent)
            temp = obj.heap{index};
            obj.heap{index} = obj.heap{parent};
            obj.heap{parent} = temp;
            temp = obj.priority(index);
            obj.priority(index) = obj.priority(parent);
            obj.priority(parent) = temp;
            obj.bubbleUp(parent);
        end
    end
    
    function bubbleDown(obj, index)
        left = 2*index;
        right = 2*index + 1;
        minIndex = index;
        if left <= obj.count && obj.priority(left) < obj.priority(minIndex)
            minIndex = left;
        end
        if right <= obj.count && obj.priority(right) < obj.priority(minIndex)
            minIndex = right;
        end
        if minIndex ~= index
            temp = obj.heap(index);
            obj.heap{index} = obj.heap{minIndex};
            obj.heap{minIndex} = temp;
            temp = obj.priority(index);
            obj.priority(index) = obj.priority(minIndex);
            obj.priority(minIndex) = temp;
            obj.bubbleDown(minIndex);
        end
    end
end
end