Dynamic estimation of an object's center-of-mass direction: a novel control method for robotic interaction in uncertain environments

To operate in uncertain environments, robots must dynamically interact with and recognize objects. This paper proposes a novel control method to dynamically estimate the center-of-mass of an uncertain object. In this method, a robot finger moves an object, and the moving direction of the finger is dynamically adjusted to estimate the direction of the object's center-of-mass (friction center). The primary advantage of this method is its capacity to rapidly estimate the center-of-mass direction utilizing a single contact. Once the direction of the center-of-mass is determined, this information can be used, for example, for the robot hand to grasp the object securely by surrounding its center-of-mass, ensuring stable handling without unexpected movements. Moreover, determining the center-of-mass can aid in automatically producing training data for machine learning applications. Both simulation and experimental results validate the proposed control method's efficacy, demonstrating its ability to quickly converge to the desired state. This control problem poses a significant challenge as the system has fewer actuators than degrees of freedom, indicating that this controlled system is underactuated. Nonetheless, the proposed control method operated successfully.