On Inverse Inertia Matrix and Contact-Force Model for Robotic Manipulators at Normal Impacts

State-of-the-art impact dynamics models either apply for free-flying objects or do not account that a robotic manipulator is commonly high-stiffness controlled. Thus, we lack tailor-made manipulators mounted on fixed base. Focusing orthogonal point-to-surface impacts (no tangential velocities), revisit two main elements of an model: the contact-force model and inverse inertia matrix. We collect measurements by impacting 7 DOF Panda robot against sensorized rigid environment with various joint configurations velocities. Evaluating from 150 trials, best model-to-data matching suggests viscoelastic computing matrix assuming composite-rigid body.