I have heard that LQR and MCP have common similarities. The difference is that MPC is using QP-programming and LQR using Riccati Equations. With QP-programming, constraints can be applied.
If we compare non constrained MPC and LQR, the difference is that LQR is optimal for a infinity time window and MPC is optimal for just a specific time window. I think it called time window. I hope you understand what word I want to use.
But is LQR obsolete compared to non constrained MPC? I mean, in practice, it would be better to have a basic non constrained MPC than LQR because an optimal state space model does not exist in reallity? Basic non constrained MPC uses simple least square to compute the future input signals for the system.
Are there situations there LQR is better in use than MPC?