Control of Bimanual Impedance in Reaching and Object manipulation

• Applicant: Professor Dr. David Franklin
• Subject Area: Human Factors, Ergonomics, Human-Machine Systems
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 521011355

Using cutlery, buttoning up a shirt, or cooking a meal requires precise coordination between two hands. Bimanual movements are fundamental components in activities of daily living. However, they can be heavily impaired in individuals suffering from neurodegenerative diseases and until now, can be hardly substituted by robotic devices.Stabilization of any interaction with the environment or objects is a requirement for any further manipulation. Our previous work extensively investigated this stabilization by measuring impedance control (regulation of stiffness) in unimanual tasks, and explained how humans adapt their motor commands to counteract unstable and unpredictable environments.However, we still have little understanding of how coordination between the two arms is implemented for impedance control and stability. We aim to fill this knowledge gap by investigating bimanual impedance control in three major task settings: posture, movement, and object manipulation. First, we will investigate the distribution of impedance tuning across the two arms during shared control of an object in a postural task. The goal is to examine to what degree the two arms share and coordinate their action to ensure stability. Second, we will examine how individuals adapt, generalize and transfer impedance tuning in a bimanual reaching task. This will enable us to identify signals which drive the formation of the internal model and if this model can be transferred to different contexts. Third, we will merge the findings from the previous research questions and will explore impedance tuning in bimanual object manipulation within the 3D environment, involving both static stabilization as well as dynamic movement. Here, the influence of accuracy demands and handedness on impedance strategies, and the temporal evolution of impedance tuning will be assessed. Taken together, our basic research approach enables us to provide crucial insights into neural processes governing the bimanual stabilization of interaction with objects. This will create an impact on neurodegenerative rehabilitation regimes, the control of robotic devices and upper-limb prostheses as well as human-robot interaction.

• DFG Programme: Research Grants
• Major Instrumentation: 2 x Phantom 1.5 High Force Robots and Structure