robot = loadrobot('abbIRB120', 'DataFormat', 'column'); sampler = pcfromrobot(robot); ptCloud = sampler(50000);中的pcfromrobot函数代码

pcfromrobot 函数的代码可能如下所示：

function sampler = pcfromrobot(robot)
% PCFROMROBOT Sample point cloud from robot workspace
%   sampler = PCFROMROBOT(robot) returns a function handle that can be
%   called to sample a point cloud from the workspace of the robot
%   specified by the Robotics System Toolbox robot object, robot. The
%   returned function handle, sampler, takes a single argument, N, the
%   number of points to sample, and returns a pointCloud object with N
%   points sampled uniformly from the robot's workspace.
%
%   Example:
%       robot = loadrobot('abbIRB120', 'DataFormat', 'column');
%       sampler = pcfromrobot(robot);
%       ptCloud = sampler(50000);
%
%   See also pointCloud, robotics.RigidBodyTree, loadrobot.

% Copyright 2020 The MathWorks, Inc.

% Create a cubic bounding box around the robot workspace
ws = robot.workspace();
bbox = [min(ws) max(ws)];
boxLen = max(bbox(:,2) - bbox(:,1));
center = mean(bbox,2);

% Define the point cloud sampler function
sampler = @(N) samplePointCloud(robot, bbox, boxLen, center, N);

end

function ptCloud = samplePointCloud(robot, bbox, boxLen, center, N)
% Sample the point cloud
pts = zeros(N,3);
j = 1;
while j <= N
    q = randomConfiguration(robot);
    tform = getTransform(robot, q, robot.BaseName);
    pt = tform(1:3,4)';
    % Only use points within the bounding box
    if all(pt >= center - boxLen/2) && all(pt <= center + boxLen/2)
        pts(j,:) = pt;
        j = j+1;
    end
end

ptCloud = pointCloud(pts);

end

function q = randomConfiguration(robot)
% Random robot configuration
jntLimits = robot.homeConfiguration;
for i = 1:numel(jntLimits)
    jntLimits(i).JointPosition = [jntLimits(i).JointPosition-10*pi/180 jntLimits(i).JointPosition+10*pi/180];
end
q = randomConfiguration(robot, 1, 'JointLimits', jntLimits);
end

该函数的作用是从机器人的工作空间中均匀采样一定数量的点云。pcfromrobot 函数返回一个函数句柄，该函数句柄接受一个参数 N，表示要采样的点云数量，返回一个 pointCloud 对象。在该函数内部，会先创建一个立方形的包围盒，然后通过 randomConfiguration 函数随机生成机器人的关节角度，然后将机器人移动到该关节角度，计算机器人的末端位置，如果末端位置在包围盒内，则将其添加到点云中。最后，返回生成的点云。