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These are questions asked by uomcsg

I computed A and B matrices, now I want to write it in state space reperentation.

diff(x(t), t) = A*x(t)+B*u


diff(x(t), t) = (Vector(6, {(1) = diff(alpha(t), t), (2) = diff(alpha(t), t, t), (3) = diff(y(t), t), (4) = diff(y(t), t, t), (5) = diff(theta(t), t), (6) = diff(theta(t), t, t)}))

So I calculated A*x(t)+B*u and got this:

(Vector(6, {(1) = diff(alpha(t), t), (2) = diff(alpha(t), t, t), (3) = diff(y(t), t), (4) = diff(y(t), t, t), (5) = diff(theta(t), t), (6) = diff(theta(t), t, t)})) = (Vector(6, {(1) = 0, (2) = k/(J*R), (3) = 0, (4) = k/(M*R*r), (5) = 0, (6) = -k/(M*R*r*l)})).e+(Vector(6, {(1) = diff(alpha(t), t), (2) = -k^2*(diff(alpha(t), t))/(J*R), (3) = diff(y(t), t), (4) = -k^2*(diff(y(t), t))/(M*R*r^2)-m*g*theta(t)/M, (5) = diff(theta(t), t), (6) = k^2*(diff(y(t), t))/(M*R*r^2*l)+(M+m)*g*theta(t)/(M*l)}))

where u=e but the formation is not A*x(t)+B*u anymore. How can I enforce Maple to output the result in the form of A*x(t)+B*u?

Hi all,

I have the following expression,

Typesetting[delayDotProduct](b, K[P], true)+k*K[D]-(Typesetting[delayDotProduct](b, m[1], true)+Typesetting[delayDotProduct](b, m[2], true)+K[D]*m[2])*k*K[P]/(Typesetting[delayDotProduct](b, K[D], true)+k*m[1]+k*m[2]+K[P]*m[2]-m[1]*m[2]*(Typesetting[delayDotProduct](b, K[P], true)+k*K[D])/(Typesetting[delayDotProduct](b, m[1], true)+Typesetting[delayDotProduct](b, m[2], true)+K[D]*m[2]))

where K and K_P are the controller gains, k is the stiffness, b is the damper, m1 and m2 are masses.

How can I find the condition on variables such that the numerator of this expression is greater that zero?

The conditions should appear as inequalities.







Download Routh-Hurwitz_stability.mw


Hello everyone,

I am experiencing a strange result. The Theta_double_dot got equated to zero in line 1.7. Please see the red arrow.

(I am using the Physics package)

How can I solve this issue?


I used the interface(typesetting = extended) command to change the notation used for time derivative of o variable.

But it doesn't seem to be working well when the variable is in the supercript form (check the last line).

How can I solve this issue?



I have modeled a delta type parallel manipulator for performing CPR operation.

The model does 100 compressions per minute with a vertical displacement of 4-5 cm, which is the requirement of the CPR.

A rigid body is attached to the end effector and I need to model a human chest using a spring damper system.

The exists a spring-damper block in the 1D Mechanical translation category. I have previosly modeled a spring damper mechanical system using these blocks but I have never tried connecting these to a Multibody.

The spring and damper coefficients of a human chest are k=8350 N/m and c=500 Ns/m.

My model is here:

Can you help me model the human chest?



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