Regularized Deep Signed Distance Fields for Reactive Motion Generation

Puze Liu, Kuo Zhang, Davide Tateo, Snehal Jauhri, Jan Peters, and Georgia Chalvatzaki
Techinal University Darmstadt

Robots in Factory

Robot in Daily Life

  • Safety

Robot in Daily Life

  • Safety
  • Unstructured Environments
  • Delicate Manipulation
  • Dynamical Human Behavior
How can we achieve dexterous
manipulation task in dynamic
environments without collisions?

Distance-based Constraints

Primitives approximation

Spheres, Cylinders

  • Simple Computation
  • Globally Well-Defined
  • Poor Scalibility for Complex Geometries
Function approximation

Neural Network

  • Powerful Local Representation
  • Handle Complex Shapes
  • Poor Extrapolating Ability

ReDSDF: Regularized Deep Signed Distance Field

  • Simple Computation
  • Globally Well-Defined
  • Powerful Local Representation
  • Handle Complex Shapes
  • Poor Scalibility for Complex Geometries
  • Poor Extrapolating Ability
  • Articulated Objects

$$ d_{\vq}(\vx) = \left[1-\sigma_{\vtheta}(\vx, \vq)\right]\textcolor{YellowGreen}{\underbrace{f_{\vtheta}(\vx, \vq)}_{\mathrm{NN}}} + \sigma_{\vtheta}(\vx, \vq)\textcolor{orange}{\underbrace{\lVert \vx - \vx_c \rVert_2}_{\mathrm{Point\,Dist.}}}$$

ReDSDF: Regularized Deep Signed Distance Field

$$ d_{\vq}(\vx) = \left[1-\sigma_{\vtheta}(\vx, \vq)\right]\textcolor{YellowGreen}{\underbrace{f_{\vtheta}(\vx, \vq)}_{\mathrm{NN}}} + \sigma_{\vtheta}(\vx, \vq)\textcolor{orange}{\underbrace{\lVert \vx - \vx_c \rVert_2}_{\mathrm{Point\,Dist.}}}$$

$ \sigma_{\vtheta}(\vx, \vq) = \sigmoid\left(\textcolor{OrangeRed}{\alpha_{\vtheta}}\left( \lVert\vx - \vx_c\rVert_2 - \textcolor{OrangeRed}{\rho_{\vtheta}} \right)\right) $

Data Augmentation and Training

Obtain Point
Cloud


Obtain Point
Cloud


Estimate Normal
Directions


Obtain Point
Cloud


Estimate Normal
Directions


Filter Out
Outliers


Obtain Point
Cloud


Estimate Normal
Directions


Filter Out
Outliers


Augment Data
Point


Obtain Point
Cloud


Estimate Normal
Directions


Filter Out
Outliers


Augment Data Point


Down Sampling


$$ \mathcal{L}(\mathcal{D}) = \sum_{\mathcal{D}} \underbrace{\omega_{\vq}(\vx)\left(\bar{d}_{\vq}(\vx) -d_{\vq}(\vx)\right)^2}_{\mathrm{Weighted\,MSE}} + \underbrace{\left( \lVert D_{\vq}(\vx)\bar{\vn}_{\vq}(\vx)\rVert^2_2 + \lVert N_{\vq}(\vx)\nabla_{\vx} d_{\vq}(\vx)\rVert^2_2 \right)}_{\mathrm{Normal\, Direction\; Alignment}} + \underbrace{\gamma\rho_{\vtheta}(\vx,\vq)^2}_{\mathrm{Regularizer\,\\Switching\,Radius}} $$

Obtain Point
Cloud


Estimate Normal
Directions


Filter Out
Outliers


Augment Data Point


Down Sampling


ReDSDF Reconstruction


Table


Shelf

ReDSDF Reconstruction

Table

Shelf

Tiago

Human

ReDSDF Extrapolation Results

Ground Truth

ReDSDF

DeepSDF

ECMNN

Reactive Motion Generation: Distance Computation

ReDSDF: Points of Interest

Sphere Approximation

Reactive Motion Generation: Bi-Manipulation

No Avoidance

Collision

Sphere Based

Oscillation

ReDSDF

Smooth Motion

Human Robot Interaction

Distance Field:
$\;\frac{1}{3} \vd_{\mathrm{human,robot}} - 0.25$

Human Robot Interaction

Distance Field:
$\;\frac{1}{3} \vd_{\mathrm{human,robot}} - 0.25$

Distance Field at 0.1m

Take Home Message

Regularized Deep
Signed Distance Fields Provides A Smooth, Fine-Grained Distance Function at Any Scale for Articulated Objects