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HDVIO: Improving Localization and Disturbance Estimation with Hybrid Dynamics VIO

Author: Cioffi

Year: 2023

Notes:

  • hybrid dynamics model: point mass vehicle model + learned component to model aerodynamics effect
  • estimates external forces + robot state
  • history of thrust and IMU to predict dynamics
  • soa VIMO only consider drône as a point mass without aerodynamics effects
  • IMU + thrust commands -> temporal NN
  • the TNN needs only position and velocity signals for training (no gt needed)
  • dynamic equation: $$ \dot{\boldsymbol{v}}{\mathcal{B}k}^{\mathcal{W}}=\boldsymbol{R}{\mathcal{B}k}^{\mathcal{W}}\left(\boldsymbol{f}{t_k}^{\mathcal{B}}+\boldsymbol{f}{\text {res } s_k}^{\mathcal{B}}+\boldsymbol{f}_{e_k}^{\mathcal{B}}\right)+\boldsymbol{g}^w $$
  • $\boldsymbol{f}{t_k}^{\mathcal{B}}$ is the mass normalized thrust, $\boldsymbol{f}{e_k}^{\mathcal{B}}$ is the external force acting on the platform, $\boldsymbol{f}_{\text {res } s_k}^{\mathcal{B}}$ is a residual term that takes into account aerodynamic effects
  • use only the gyro for rotation
  • sliding window MAP estimation with vision, pre integ, dynamics and marginalization
  • the dynamic residual is the difference between the actual delta position and velocity and the one obtained by integrating dynamic equations with estimated forces using discrete time Euler numerical integration
  • TCN = as powerfull as RNN but with less computations
  • the loss of the CNN is the same as in the factor graph but opitimising on $\boldsymbol{f}_{e_k}^{\mathcal{B}}$
  • Similar perfo of the TCN wrt methods using full state
  • TCN exhibits good generalization to situations unseen while training