AltN research has been working with roboFold to develop a new method of sheet metal forming which does not require any forms or tooling. In this method, material is simply scored on curved fold-paths and bent into form using 6axis robots. One of the advantages of this method is that different parts can be created with the same efficiency as copies of a single one.
To begin this process we have been developing a 1:5 scale prototype. Alt-N’s role in this work has been to develop the simulation and control software for the robots. This process can also be scaled up to the next stage using industrial robots
First we take a take a target geometry that has been animated flat. For these initial tests a physical model is digitized and then mathematically calculated to its starting position. From this all of the steps in-between can be calculated. (This process has been undertaken @ TU Vienna)
Next we determine the hand positions of each robot and calculate the 3 average normals as they change during the bending
These points must then be related to the range of movements possible over the 6 axes of the robots
The hands are then attached in the digital simulation and as the surface folds, it drives the kinematics of the robots. Due to the physical limitations, each of the robots have to be solved to follow 4 points instead of a standard single end-effector. As the surface drives each of the 18 joint angles a background algorithm converts them into the pulse-width values for each individual joint which were determined when calibrating the robots.
As we are developing the process from scratch, the simulation outputs a text file which contains the raw pulse-width data for each of the 18 servos. The process is similar to Gcode with a CNC where the router is fed the 3 XYZ coordinates over time, only in this case we have to send the 18 pulse-width values to control the position of each servo.
The material is then scored and the hands are attached with the vacuum grippers. The coordinates are fed to the robots over the terminal and the material is folded.
Repeat as necessary.
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