Achieving High-Quality Haptic Feedback in Robot-Assisted Surgery With a Model-Based Approach

One of the major disadvantages of robot-assisted surgery is the absence of haptic feedback. A haptic user interface (HUI), which is part of a telemanipulation system addressing this issue, is described. To generate high-quality haptic feedback using the HUI, it is necessary to have a precise understanding of the system's behavior. The capstan drive of the HUI is modeled as a rotational two-mass system. The mechanical parameters are determined by minimizing the error between the mechanical transfer function, defined by motor torque as input and velocity as output, and measured frequency responses. The relationship between motor current and torque is approximated as Fourier series depending on the motor angle. Friction is modeled as Coulomb and viscous friction, Stribeck curve, and continuous approximation of the Stribeck curve. The model is utilized to enhance the precision of the generated feedback force. The described system enables the generation of haptic feedback with a maximum force of 6 N, a force resolution of 0.05 N, and a usable frequency bandwidth of 31 Hz.