3d block printing: additive manufacturing by assemblymaeda/research/iros2019ws-poster.pdf · 3d...
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3D Block Printing: Additive Manufacturing by Assembly
This paper overviews a robotic 3D block printer. It can fabricate 3D forms from their CAD models by assembling toy blocks as digital materials. It can achievemass customization through the combination of mass-produced building blocks and automatic assembly planning for customized shapes. In this paper, wepresent mechanical analysis for assembly planning of toy blocks and ROS-based implementation of the system for high interoperability with various robots.
3D Block Printing [Maeda 2016 IROS] [Sugimoto 2017 CASE]
Mechanical Analysis of Block Assembly
ROS-based Implementation of Block Printer
Yusuke MAEDA, Mikiya KOHAMA and Chiharu SUGIMOTO(Yokohama National University)
Maeda Lab, Dept. of Mech. Eng., Yokohama National University https://www.iir.me.ynu.ac.jp/
Additive manufacturing by assembly of digital materials
• Mass customization using mass-produced building blocks• Multiple colors and materials• High repeatability by using precision digital materials and their
self-alignment• Material reuse through disassembly• Fabrication of shapes with function using functional blocks
(e.g., electric circuits)
Potential Advantages
Block assemblability test is necessary for assembly planning
A new implementation of block printerbased on ROS and MoveIt
Experimental Setup
System Architecture
Interoperability with Various Robots
• For higher interoperability with various robots• Motion planning for collision avoidance
Our 3D Block Printer
• Using nanoblocks (LEGO-like, but smaller)• Layer-by-layer assembly from bottom to top• Automatic assembly planning from a CAD model
Dealing with unprintable shapes
• e.g., overhang
☹ Place A before B
☺ Place B before A
Block modelCAD model Subassemblies with support blocks
Final assembly
manual assembly
Assembly Example
6-axis CartesianSCARA
• Our previous study: empirical assemblability test• Using variously-sized blocks was difficult
Assemblability test for block placement
Capacity [Luo 2015]
• A force margin of inter-block connection• Applicable to evaluation of the physical stability of LEGO-like block sculptures• Only for assembled block sculptures
Must be extended for the physical stability of block sculptures during the placement of each block
Check whether the minimum capacity is positive by solving the following linear programming problem:
Normal Force ℱ
Friction Force ℱ
Normal Force ℱ
𝑥
𝑧
𝑥
𝑦
𝑥
𝑦
𝑥
𝑧
Normal Force ℱ
Friction Force ℱ
Normal Force ℱ
Front view (1x1)Top view (1x1) Front view (2x2)Top view (2x2)
minimum capacity
capacity at the i-th connection
external wrench exerted to thej-th block including insertion force
auto-conversion auto-assembly
using support blocks
decomposing into subassemblies
AB
A B
Manipulator
Assembly Pad
Block Feeder
Gripper
Model Reader
Interface
PickPlanner
PlacePlanner
MotionCommander
Core
Robot Control Package
Block ModelPick
Calibration
PlaceCalibration
MoveIt!Interface
MoveIt!
ObjectSpawner
Robot Model(URDF)
Hardware
RobotController
Robot
ROS Parameter
ROS Node
… Command FlowGripper
GripperController Hardware
GripperCalibration
Block Feeder
Manipulator(VP‐6242‐G)
Gripper(ESG1‐FS‐2840)
Assembly Pad