% 定义机器人参数 du = pi/180; L1(1) = Link('theta', 90du+0.02, 'a', 0.001, 'alpha', 0.003, 'qlim', [180du, 365du], 'modified'); L1(2) = Link('d', 0.001, 'a', 185+0.0079, 'alpha', 0.001, 'qlim', [3du, 63du], 'modified'); L1(3) = Link('d', 90/du+0.005, 'a', 0.005, 'alpha', pi/2+0.005, 'qlim', [60du, 120du], 'modified'); L1(4) = Link('theta', 0, 'a', 120+0.12, 'alpha', pi/2, 'qlim', [230du, 326du], 'modified'); L1(3).theta = L1(3).theta + 0.023; L1(4).theta = L1(4).theta + 0.08; Needle = SerialLink(L1, 'name', 'Needle'); % 定义误差量 delta_a = 0.001; % 长度误差 delta_q = 0.01du; % 关节角度误差 delta_alpha = 0.0001; % 关节轴线误差 % 计算末端执行器的初始位姿 q = [0 0 0 0]; % 初始关节角度 T = Needle.fkine(q); % 正运动学 % 添加误差量并计算末端执行器的位姿 for i = 1:100 % 添加长度误差 L1(2).a = L1(2).a + delta_a; Needle = SerialLink(L1, 'name', 'Needle'); T1 = Needle.fkine(q); err1 = tr2delta(T, T1); % 添加关节角度误差 L1(1).theta = L1(1).theta + delta_q; Needle = SerialLink(L1, 'name', 'Needle'); T2 = Needle.fkine(q); err2 = tr2delta(T, T2); % 添加关节轴线误差 L1(3).alpha = L1(3).alpha + delta_alpha; Needle = SerialLink(L1, 'name', 'Needle'); T3 = Needle.fkine(q); err3 = tr2delta(T, T3); % 计算误差的欧氏距离 err(i) = norm([err1, err2, err3]); end % 绘制误差曲线 plot(err); xlabel('Number of iterations'); ylabel('Euclidean error'); title('Geometric error model');这段代码怎么修改我可以输入一组关节角度值然后得到误差值

你可以将代码封装为一个函数，输入参数为关节角度值，输出为误差值。具体修改如下：

function [err] = calculate_error(q)
% 定义机器人参数
du = pi/180;
L1(1) = Link('theta', 90du+0.02, 'a', 0.001, 'alpha', 0.003, 'qlim', [180du, 365du], 'modified');
L1(2) = Link('d', 0.001, 'a', 185+0.0079, 'alpha', 0.001, 'qlim', [3du, 63du], 'modified');
L1(3) = Link('d', 90/du+0.005, 'a', 0.005, 'alpha', pi/2+0.005, 'qlim', [60du, 120du], 'modified');
L1(4) = Link('theta', 0, 'a', 120+0.12, 'alpha', pi/2, 'qlim', [230du, 326du], 'modified');
L1(3).theta = L1(3).theta + 0.023;
L1(4).theta = L1(4).theta + 0.08;
Needle = SerialLink(L1, 'name', 'Needle');

% 定义误差量
delta_a = 0.001; % 长度误差
delta_q = 0.01du; % 关节角度误差
delta_alpha = 0.0001; % 关节轴线误差

% 计算末端执行器的初始位姿
T = Needle.fkine(q); % 正运动学

% 添加误差量并计算末端执行器的位姿
for i = 1:100
    % 添加长度误差
    L1(2).a = L1(2).a + delta_a;
    Needle = SerialLink(L1, 'name', 'Needle');
    T1 = Needle.fkine(q);
    err1 = tr2delta(T, T1);
    
    % 添加关节角度误差
    L1(1).theta = L1(1).theta + delta_q;
    Needle = SerialLink(L1, 'name', 'Needle');
    T2 = Needle.fkine(q);
    err2 = tr2delta(T, T2);
    
    % 添加关节轴线误差
    L1(3).alpha = L1(3).alpha + delta_alpha;
    Needle = SerialLink(L1, 'name', 'Needle');
    T3 = Needle.fkine(q);
    err3 = tr2delta(T, T3);
    
    % 计算误差的欧氏距离
    err(i) = norm([err1, err2, err3]);
end
end

然后，你可以调用这个函数，输入关节角度值，得到误差值：

q = [0, 0, 0, 0]; % 输入关节角度值
err = calculate_error(q); % 得到误差值