Robotic device and method for artistic pen drawing on arbitrary surfaces

Robotic arm for curved-surface pen drawing using stroke-based control points and pen-pressure-based virtual surface recalibration

This technology is a device and method where an input device saves drawings stroke-by-stroke and transmits them wirelessly to a processor, which predicts the drawing surface and directs a robotic arm equipped with a pen to draw on arbitrary surfaces. Each stroke is represented by a set of control points—comprising start, middle, and end points—along with pen pressure and color data.

Previously, if the drawing surface was not flat or lacked geometric model information, the robotic arm could not accurately determine the surface shape. This led to inconsistent pen pressure or gaps in strokes caused by the pen losing contact with the surface.

This technology applies impedance control to the pen tip to detect the force applied to the surface in real time. If the force falls outside the 0.8N–3.2N range, it recalibrates the virtual surface by a preset distance to restore proper pen pressure. Before drawing, the robotic arm moves along pre-programmed curves to map the surface, and it can be equipped with multiple pens to switch colors as needed. Applicable to decorating ceramics and crafts, drawing on store windows and interior walls, and use in robot art exhibitions and educational kits, it can seamlessly reproduce the pressure and color of human-drawn strokes even on curved surfaces without prior geometric data.

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Key Features:

• An input device comprising a first wireless communication module that communicates with a processor and a storage unit that saves input drawings as individual stroke data
• A robotic arm with a pen attached to its end, which draws on an arbitrary surface based on information received from the processor
• A calculation unit that recalibrates the virtual surface by a preset distance when the pen's pressure exceeds or falls below a specified range
• A set of control points consisting of start, middle, and end points, along with pen pressure and color data transmitted from the input device

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This invention was developed with support from the Ministry of Science, ICT and Future Planning for research on stable simulation-based computer animation using differentiable distance operators.

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