Cubic poly trajectory function

I am using matlab2018b and I can't use cubicpolytraj function. please what's the alternative function I can use. Thanks

Answer 1

[Sam Chak]

Hi @Odesanmi Gbenga Abiodun

One practical alternative and a mearning way to learn how to generate 3rd-order trajectories is to mathematically derive the 3rd-order polynomical function yourself:

or to use the formula directly:

Say you to get from Point A to Point B in 4 seconds:

t = linspace(0, 4, 401);
A = [2, 3];
B = [5, 7];
x = 2 + (3*(t/4).^2 - 2*(t/4).^3)*(5 - 2);
y = 3 + (3*(t/4).^2 - 2*(t/4).^3)*(7 - 3);
plot(t, [x; y]), ylim([1 8]), grid on, 
xlabel('t'), ylabel('Positions'), legend('X-positions','Y-positions')

Or get a 3rd-party MATLAB code from File Exchange.

https://www.mathworks.com/matlabcentral/fileexchange/66326-3rd-trajectory-planning

plot([A(1), B(1)], [A(2), B(2)], 'o'), hold on
plot(x, y), xlim([1 6]), ylim([2 8]), grid on, 
xlabel('x'), ylabel('y'),

[Odesanmi Gbenga Abiodun]

Thanks for your help, please in my case I am having 3x5 points of this example： wapoints = [-0.525;-0.2;0.9],[-0.025;-0.6;0.5], [0.425;-0.3;0.7],[-0.025;-0.55;1.1],[-0.525;-0.2;0.9]]; please can I have a similar example? Thanks

[Sam Chak]

You are welcome, @Odesanmi Gbenga Abiodun. Yes, you can apply exactly the same formula to find the 4 sets of 3rd-order polynomial functions for the five (5) waypoints in 3D {x, y, z} coordinates.

If you find the formula, example, MATLAB code helpful, please consider accepting ✔ and voting 👍 the Answer. Thanks!