Tactile Sensing for the PR2
Joe Romano, a PhD student from the Penn Haptics Group, spent the summer at Willow Garage enabling the PR2 to perform fine motor control with its grippers using tactile information, as well as understand a variety of other tactile cues. Joe's approach attempts to recreate the same sensory information that humans use when completing similar tasks. This information has already been used to allow the robot to quickly stop after contact before damaging itself or the environment, naturally pass objects to a person, or detect when an object has been set down on a tabletop.
The goal of this work was to allow the robot to understand the sensory information that arises from contact with the environment, intelligently reason about what is happening in the world, and decide what the appropriate robot response should be. Using this tactile approach, the PR2 can delicately grasp a wide range of unknown objects, such as raw fruit, eggs, and heavy liquid-filled containers, all without crushing or dropping them. The PR2 can also quickly detect contacts between its arms and objects in the world, as well as contact between hand-held objects and the world.
The sensory-signals that people receive can be mimicked by processing information from pressure-sensors in the fingertips of the PR2 and accelerometers mounted in the palm of the robot. These signals can then be used to do tactile-event-driven control of the robot, such as pushing a button until it clicks, or grasping an object tightly enough until it stops slipping out of the gripper.
To learn more about Joe's work, click here. For more technical information, please see Joe's presentation slides below.