Periodic robust robotic rock chop via virtual model control

2025-08-04

AI Summary

Robotic cutting faces significant challenges including unknown object mechanics, high contact forces, and stringent motion accuracy requirements. This paper proposes a planning-free, periodic control framework based on a virtual dynamic model: an equivalent mechanical system—comprising interconnected virtual springs, dampers, and masses—is constructed, and Virtual Model Control (VMC) is employed to autonomously generate adaptive tool rocking motions without predefined trajectories or environmental priors. The method exhibits strong robustness, naturally accommodating variations in tool geometry, cutting board height, and physical properties across diverse vegetables. Implemented on a Franka Emika Panda robot, it achieves an average cutting frequency of 1 Hz, with slice thickness errors maintained within ±0.5 mm (target range: 1–6 mm). The approach successfully cuts five vegetable types and demonstrates cross-platform transferability to other robotic systems.

Technology Category

• Intelligent Robots: Motion and Path Planning
• Computer Vision: Vision for Robotics & Autonomous Driving
• Planning, Routing, and Scheduling: Mixed Discrete/Continuous Planning

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Virtualization and resource management in Web systems and infrastructures
• Responsible Web: Machine-in-the-loop, human agency and autonomy
• User Modeling, Personalization and Recommendation: User modeling and simulation for interactive and conversational systems

Abstract

Robotic cutting is a challenging contact-rich manipulation task where the robot must simultaneously negotiate unknown object mechanics, large contact forces, and precise motion requirements. We introduce a new virtual-model control scheme that enables knife rocking motion for robot manipulators, without pre-planned trajectories or precise information of the environment. Motion is generated through interconnection with virtual mechanisms, given by virtual springs, dampers, and masses arranged in a suitable way. Through analysis and experiments, we demonstrate that the controlled robot behavior settles into a periodic motion. Experiments with a Franka manipulator demonstrate robust cuts with five different vegetables, and sub-millimeter slice accuracy from 1 mm to 6 mm at nearly one cut per second. The same controller survives changes in knife shape and cutting board height, and adaptation to a different humanoid manipulator, demonstrating robustness and platform independence.

Problem

• Enables robotic knife rocking without pre-planned trajectories
• Handles unknown object mechanics and large contact forces
• Achieves robust cuts with sub-millimeter slice accuracy

Innovation

• Virtual-model control for robotic cutting
• Interconnection with virtual mechanisms
• Periodic motion without pre-planned trajectories