need help for robotics sliding mode control execution in matlab

i am doing research in the topic of Distrubance observer control of robotic manipuator in healthcare applications. for this i need a code / diagram and exection in the control methods of robotics in matlab / phyton. if anyone have an idea about this, its helpful for me.

Answer 1

[Sam Chak]

Hi @saravanapandian

I am not familiar with your robotic research. But here is a code snippet for a simple Disturbance Observer that you can apply to your robotic sliding mode control work.

%% Disturbance Observer-based Control for Double Integrator systems
function dx = simpleDOBC(t, x)		
	dx      = zeros(3, 1);
    
    % parameters
    xd      = 0.2;  % desired position
    m       = 3;    % mass
    d       = 0.5;  % disturbance load
    k1      = 1;    % proportional gain
    k2      = 1;    % derivative gain
    k3      = 1;    % observer gain
    
    % controller
    u       = - x(3) - m*k1*x(2) - x(1) + xd - k2*x(2) - k1*k2*x(1) + k1*k2*xd;
    
    % most mechanical systems can be expressed as a Double Integrator system
	dx(1)   = x(2);
	dx(2)   = (u + d)/m;
    
    % disturbance observer
	dx(3)   = k3*(x(2) + k1*x(1) - k1*xd);
end
		
x0      = [1; 0; 0];    % initial values
tspan   = linspace(0, 25, 2501);
[t, x]  = ode45(@simpleDOBC, tspan, x0);
plot(t, x(:, 1)), grid on
xlabel('Time, t')
title('System''s Position')

●

plot(t, x(:, 3)), grid on
yline(0.5, '--')
xlabel('Time, t')
title('Disturbance estimated by the Observer')