David Cho

9 Questions 6 Answers 0 Followers

Questions related from David Cho

How to solve an optimization problem with stability constraints using 'fmincon'?

Hi, Let us say that a plant model of the following form is given: \dot{q} = A*q + B*u, y = C*q. The output of the model (y) is its position (x) and velocity (v). Using this output, I am going to...

02 April 2019 9,369 3 View

Relative weight between two weight matrices in optimal control?

Hi, the standard form of a quadratic optimal control problem is given by J = 1/2 * integration (x'*Q*x + u'*R*u) {dt}, where Q and R are weight matrices. If we consider a second-order system with...

07 February 2018 9,142 1 View

How to improve an MPC (Model Predictive Control) performance?

Hi, I'd like to regulate an output of a second-order system using MPC. But I always get a result with a huge undershoot. Could anyone let me know how to remove this undershoot? I've changed weight...

30 January 2018 653 2 View

Why do PID controllers work well for nonlinear systems?

Hello, As far as I know, PID controllers are most widely used in the industry although all real-life systems are nonlinear. Is there any mathematical proof that PID controllers (with sufficiently...

01 March 2017 2,579 3 View

What are the uses of a Lagrangian?

Hello, If a Lagrangian is known for a given system, we can deduce its equation of motion using the Lagrange equation. Are there any other uses of a Lagrangian? One use I know is to find a...

01 March 2017 4,184 7 View

Why should mismatched uncertainties be treated separately from matched uncertainties?

Hello, I am studying sliding mode control and have found that many references distinguish mismatched uncertainties from matched ones. I know that mismatched uncertainties do not enter the input...

01 February 2017 5,996 5 View

In spite of chattering, why is sliding mode control studied so extensively?

Hi I am studying adaptive sliding mode control. In many papers, the control law is defined as u = u_nom - K(t)*sign(s), where u_nom is 'ideal control' that is continuous assuming no uncertainties...

09 April 2016 1,706 12 View

How to solve an ODE with parameters calculated in another function?

Hi I want to solve an ODE with parameters calculated in another function. For example, I have the following ODE: dy/dx = -5*y + f where f is obtained in another function with a very complicated...

16 December 2015 3,021 4 View

Sliding mode control approaches that do not need the bounds of uncertainties?

As far as I know, conventional sliding mode control technique requires the upper bounds of uncertainties to prove the Lyapunov stability. However, sometimes estimating these bounds is very hard or...

28 September 2015 9,162 7 View