Providing haptic perception to telerobotic systems via tactile acceleration signals

Touching a real physical object with a hand-held tool causes the tool to experience high-frequency (tactile) accelerations that reflect the mechanical characteristics of the contact. These haptic signals provide salient cues about changes in tool-surface contact state and enable effortless identification of material and surface properties. While humans make extensive use of these cues, robots almost universally cannot sense them, and they are seldom provided to the operators of telerobotic systems. Fortunately, the recent availability of low-cost high-bandwidth accelerometers makes it practical to give telerobotic systems the capability of sensing and using these cues. This dissertation presents a suite of methods we have developed for enabling operators of telerobotic systems to use tactile accelerations to be more aware of their physical interactions with the remote environment. The focus is on the modeling, design and control of a haptic system capable of accurately recreating tactile acceleration signals experienced by a teleoperated robot in real time. This system has been implemented on multiple robotic systems, including the Intuitive Surgical da Vinci Surgical System, an FDA-approved telerobotic system that natively provides no haptic feedback. Building on prior work, we use MEMS-based accelerometers to provide real-time measurement of the high frequency accelerations experienced by the robot as a result of environmental contact. We use a dedicated linear voice coil actuator to generate high fidelity recreations of the tactile acceleration signals for the user to feel at the operator interface. This approach involves signal processing methods to enhance the measured accelerations and dynamic modeling to carefully control the acceleration output of the voice coil actuator. The provided feedback feels natural and promises to reduce the operator\u27s cognitive load and increase their situational awareness. A number of experiments confirm the feasibility and performance qualities of these systems. Additionally, we have preliminary evidence that tactile acceleration measurements can be a useful objective measure of the operator\u27s technical skill in telerobotic surgery