Unable to understand the IPOPT output(IMODE=6)

[Sushanth B Mullangi]

Respected Sir,

I am using gekko optimization tool to control a self -driving-car(level 2 autonomous) using Model Predictive Control(MPC) which is IMODE=6.

Firstly,

I am unable to understand the outputs(which i get when i give "Disp=True")

I have attached a screenshot for your reference.

Secondly after the optimization ,The value of the Manipulated Variable(MV) which is input to the car in my case(throttle and steering angle ) remains zero .

Thus the car is not moving !  I dont why this is happening

Sir please help me resolve this issue.

I would be very grateful to you if you could help me .

Note:

I have used Kinematic Bicycle Model to model the vehicle

Thank you,

Sushanth BM

[John Hedengren]

Here is an explanation of IPOPT solver columns: https://apmonitor.com/wiki/index.php/Main/OptionApmSolver and a more detailed explanation in the IPOPT documentation: https://coin-or.github.io/Ipopt/OUTPUT.html  If the solver does not converge to a solution then you should not trust the predictions (such as throttle=0 and steering_angle=0).

Here are suggestions for dealing with an unsuccessful solution:

1. https://stackoverflow.com/questions/65329321/optimal-control-problem-using-gekko-solution-not-found

2. https://stackoverflow.com/questions/66977417/solution-not-found-error-using-gekko-optimization-suite-when-changing-paramete

3. https://stackoverflow.com/questions/56942615/how-to-fix-solution-not-found-error-in-python-gekko-optimal-control-code

Please search or post to StackOverflow for future questions so that questions and responses are easier to find for others.

Thanks,

John Hedengren

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Best regards,

John Hedengren

GEKKO Optimization Suite

https://machinelearning.byu.edu

[wcottee]

I had a similar problem where the MV’s were zero. I changed their status to “1” and that fixed it. The default value is zero so the solver won’t change them.

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