/Lie-MPC-AMVs

Convex Geometric Trajectory Tracking using Lie Algebraic MPC for Autonomous Marine Vehicles

Primary LanguageRoff

Lie MPC for AMVs

Convex Geometric Trajectory Tracking using Lie Algebraic MPC for Autonomous Marine Vehicles

We propose a computationally-efficient Convex geometric error-state MPC for marine vehicles. The proposed algorithm is compared with Nonlinear MPC.

Used packages

1) OSQP : QP solver

Folder : osqp

Installation is required to run the code.

2) CasADi : NMPC solver

Folder : casadi-linux-matlabR2014b-v3.5.5

3) MPC-tools for CasADi

Folder : octave-mpctools

Tool for easy implementation of NMPC with CasADi by autonomously transforming the given dynamics model into the proper format.

4) USV Otter model from MSS

Folder : GNC, HYDRO

Control input of the otter model is changed from motor speed to thrust force.

Demonstration

Run main.m in MATLAB

Parameters

  • Reference trajectory, ocean currents, prediction horizon, simulation parameters are defined in main.m
  • MPC cost weights (P, Q, R) are defined in sim.m
  • For calculating dynamics of USV Otter, NMPC uses otter.m and NMPC-simple uses otter-simple.m. They regard ocean current as 0 m/s. True simulation is processed using otter_true.m with ocean currents.

Results

Trajectory tracking results

Computation time (sec)

Ocean Current Proposed MPC NMPC NMPC-simple
0 m/s 58 917 574
0.5 m/s 60 1143 552