Andreas Völz

Dear Karthik, was thinking whether the same will be applicable for a rocket example with depleting mass ?. So GRAMPC is not applicable here too ? Sorry for the confusion. If the dynamics can be formulated as ordinary differential equation or index-1 differential algebraic equation, GRAMPC should be applicable. For most systems this is probably the case. However, I can't tell for sure without more details about the actual system. Also even if we use ABA, GRAMPC software may be of less help for the...

Dear Karthik, for this paper I had reimplemented the core algorithm of GRAMPC in C++ in order to keep it as simple as possible and to tailor it to the special case of rigid body dynamics. In principle it would also be possible to implement the same algorithm within GRAMPC but it would be quite a lot of effort and I doubt that enough people would use this special variant to justify the effort. However, GRAMPC can still be used for MPC of systems with rigid body dynamics. It just requires using forward...

Dear Karthik, I guess that you can ignore the warnings. After all, this file is only relevant for the RODAS integrator and it is not very likely that you will use RODAS in an embedded MPC application. Best regards, Andreas Völz

Dear Ethan, In my model, Thor=6, Nhor=61, dt=0.02 In this case GRAMPC discretizes the horizon Thor=6 with Nhor=61 sampling points, which means they have a spacing of 6/(61-1) = 0.1, that is, grampc.rws.t is the vector [0, 0.1, 0.2, 0.3, ..., 5.7, 5.8, 5.9, 6.0] Now, it would be sufficient to pass the predicted disturbances at these 61 sampling points to GRAMPC, in which case you would need (t-t0)/0.1 to compute the index into the userparam array. On the other hand, your MPC is running with the sampling...

Dear Ethan, (1): I would expect Thor/(Nhor-1) but you have programmed it. What are the specific values of Thor, Nhor and dt in your case? The MHE example in GRAMPC chooses them in such a way that the sampling time along the prediction horizon corresponds to the sampling time of the controller. This definitely simplifies such tasks where you want to take predicted values into account. Otherwise, setting the values in userparam before calling grampc_run is just a little bit more complex. (2): You can...

Dear Karthik, since there exist so many different microcontrollers, it is impossible for us to provide examples or tutorials for each of them. The manufacturer of your controller probably provides some minimal examples for running own programs on the controller. I would take these as starting points and then integrate GRAMPC. If you need more help, then you should at least share such a minimal example. Best regards, Andreas Völz

Hi, I am a PhD student in optimization based control and would like to evaluate GRAMPC for implementing NMPC. I had setup the tool in my PC and able to run few examples. I had gone through documentation and some published papers also and tried PYGRAMPC also. I would like to know the compilation steps of GRAMPC for a RISC-V micro-controller. I understand its already implemented for dSpace, RH850 etc. Is there any tutorial for implementation on embedded controller (similar to the PC implementation...

Dear Krysten, I don't think I have ever seen the penalties explode so fast to PenaltyMax. Maybe the error is related to wrong gradients of the constraint, but this is really just a guess. I am now on vacation during the next weeks and won't have time to look into this problem. Maybe you can reduce it to a minimal working example (probfct,c, initData.m and startMPC.m) that still shows the behaviour and then share it with me? Best regards, Andreas Völz