Vision-based tactile sensors have recently become popular due to their combination of low cost, very high spatial resolution, and ease of integration using widely available miniature cameras. The associated field of view and focal length, however, are difficult to package in a human-sized finger. In this article we employ optical fiber bundles to achieve a form factor that, at 15 mm diameter, is smaller than an average human fingertip. The electronics and camera are also located remotely, further reducing package size. The sensor achieves a spatial resolution of 0.22 mm and a minimum force resolution 5 mN for normal and shear contact forces. With these attributes, the DIGIT Pinki sensor is suitable for applications such as robotic and teleoperated digital palpation. We demonstrate its utility for palpation of the prostate gland and show that it can achieve clinically relevant discrimination of prostate stiffness for phantom andex vivotissue.

Multi-task reinforcement learning could enable robots to scale across a wide variety of manipulation tasks in homes and workplaces. However, generalizing from one task to another and mitigating negative task interference still remains a challenge. Addressing this challenge by successfully sharing information across tasks will depend on how well the structure underlying the tasks is captured. In this work, we introduce our new architecture, Projected Task-Specific Layers (PTSL), that leverages a common policy with dense task-specific corrections through task-specific layers to better express shared and variable task information. We then show that our model outperforms the state of the art on the MT10 and MT50 benchmarks of Meta-World consisting of 10 and 50 goal-conditioned tasks for a Sawyer arm.

Tactile sensing can improve end-effector control and grasp quality, especially for free-flying robots where target approach and alignment present particular challenges. However, many current tactile sensing technologies are not suitable for the harsh environment of space. We present a tactile sensor that measures normal and biaxial shear strains in the pads of a gripper using a single optical fiber with Bragg grating (FBG) sensors. Compared to conventional wired solutions, the encapsulated optical fibers are immune to electromagnetic interference — critical in the harsh environment of space. Sampling is possible at over 1 kHz to detect dynamic events. We mount sensor pads on a custom two-fingered gripper with independent control of the distal and proximal phalanges, allowing for grip readjustment based on sensing data. Calibrated sensor data for forces match those from a commercial multiaxial load cell with an average 96.2% RMS for all taxels. We demonstrate the gripper on tasks motivated by the Astrobee free-flying robots in the International Space Station (ISS): gripping corners, detecting misaligned grasps, and improving load sharing over the contact areas in pinch grasps.