A team of researchers led by the Computational Robotics Laboratory of the Computer Science Department of ETH Zurich and the University of Haifa have used a two-armed robot to create complex 3D models.
Technology has produced a range of 3D prototypes with doubly curved surfaces, which are difficult to achieve with conventional straight wire cutting methods such as CNC machining and wire frame fabrication.
The idea of this project is to sculpt styrofoam with hot wire. The idea is to pass current through a cable to heat it enough to melt a path while guiding it through a block of Styrofoam. The hot wire cuts are smooth as silk.
A YuMi IRB 14000 robot was used for this process, equipped with two arms to make the process more efficient. Configuring the robot parameters so that they work together effectively.
The researchers were able to create 3D designs with precision. With the goal clear, the robot software produces a series of trajectories and drags one of its rods through the workpiece to create a cut.
The method of making controlled curved cuts through the foam. used a 1mm thick deformable rod that gave flexibility to the cutting tool. The robot has seven degrees of freedom in each arm, and the rod can deform long before sustaining permanent damage. Heating of the cable caused the material to melt just before contact. The researchers attributed this to the lack of rigidity in the robot’s arms and the use of the tripod mount, which restricted the precision with which it could be placed. The researchers also recognized other design limits, such as the rod used to manipulate the material, which can only bend and deform up to a certain amount until it is replaced.
YuMi IRB 14000, with double arms, can move with 7 degrees of freedom. The arm clips are attached to the ends of an inextensible elastic metal bar, which means the bar can deform and bend, but not stretch. This is important because for the idea to work, the researchers had to calculate and model the shape of the cable exactly how the robot rams move, and unplanned stretching will prevent them from predicting the shape.
Each test through the foam was evaluated to remove as much material as possible, and multiple tests are needed to slowly advance the final design.
The software used to program the robot only allows a series of cuts to be made with the robot arms, rather than allowing the creation of a masterpiece in one go. Although not tested, the Swiss researchers recognized that an increase in cable temperature could lead to higher cutting speeds, albeit with lower cutting quality.
Although this technique is in the early stages it could be applicable to other materials in the future. It would be great to see these three-dimensional sculptural works made by a double-arm YuMi robot meeting the required quality standards.