nlmpc, Error using sqpInterface Nonlinear constraint function is undefined at initial point. Fmincon cannot continue. How to fix it? Help me, please, I can give you all that you want (Script,State function and so on)

The error that appear, after first launch is:

Start of Error Report ------------------------------------------------------ Error using sqpInterface Nonlinear constraint function is undefined at initial point. Fmincon cannot continue. Error in fmincon (line 843) [X,FVAL,EXITFLAG,OUTPUT,LAMBDA,GRAD,HESSIAN] = sqpInterface(funfcn,X,full(A),full(B),full(Aeq),full(Beq), ... Error in nlmpc/nlmpcmove (line 157) [z, cost, ExitFlag, Out] = fmincon(CostFcn, z0, A, B, [], [], zLB, zUB, ConFcn, fminconOpt); Error in nmpcblock_interface (line 159) [mv, ~, Info] = nlmpcmove(nlobj, x, lastmv, ref, md, Options); ------------------------------------------------------ End of Error Report ------------------------------------------------------

Error occurred when calling NLP solver "fmincon". See the error report displayed above. Error in nmpcblock_interface.m (line 161) throw(ME) Error in 'HEAVYTRUCK_linearMPC/Nonlinear_MPC_Controller/MPC/NLMPC' (line 24)

Component:Simulink | Category:Model error

An error occurred while running the simulation and the simulation was terminated

Caused by:

• Simulation stopped because of a runtime error.

I don't know how fix it, I traied more things for to fix its, but... no results!

[Cesar García Echeverry]

did you resolve it?

[世忠]

I also met this problem. Did you solve it?

[Eri Gualter dos Santos]

世忠 Can you provide more details about the issue you are facing? Please share a reproduction example if you are able too.

[曜星]

i wonder how to solve the problem

[Torsten]

@曜星

i wonder how to solve the problem

By supplying a constraint function that outputs defined values (thus not Inf or NaN) for your initial guess.

[Ibrahim]

i wonder how to solve the problem

[ahmed sayed]

add initial condition block with dimensions equal to that of your manipulated variable vector

Answer 1

[George]

Hi all,

I had the same error arrise when I was attempting to create a NMPC for a hypersonic longitudinal model. To fix the issue I had found a bug in the aerodynamic data where a value was off by a factor of 10 (one decimal place to the right). Upon fixing this, the model worked correctly.

I'm not sure why exactly this would throw this error, but this could be the root cause, an error in the dynamics of the system.