OmniTact: A Multi-Directional High Resolution Touch Sensor (2003.06965v1)

Abstract: Incorporating touch as a sensing modality for robots can enable finer and more robust manipulation skills. Existing tactile sensors are either flat, have small sensitive fields or only provide low-resolution signals. In this paper, we introduce OmniTact, a multi-directional high-resolution tactile sensor. OmniTact is designed to be used as a fingertip for robotic manipulation with robotic hands, and uses multiple micro-cameras to detect multi-directional deformations of a gel-based skin. This provides a rich signal from which a variety of different contact state variables can be inferred using modern image processing and computer vision methods. We evaluate the capabilities of OmniTact on a challenging robotic control task that requires inserting an electrical connector into an outlet, as well as a state estimation problem that is representative of those typically encountered in dexterous robotic manipulation, where the goal is to infer the angle of contact of a curved finger pressing against an object. Both tasks are performed using only touch sensing and deep convolutional neural networks to process images from the sensor's cameras. We compare with a state-of-the-art tactile sensor that is only sensitive on one side, as well as a state-of-the-art multi-directional tactile sensor, and find that OmniTact's combination of high-resolution and multi-directional sensing is crucial for reliably inserting the electrical connector and allows for higher accuracy in the state estimation task. Videos and supplementary material can be found at https://sites.google.com/berkeley.edu/omnitact

• The paper introduces OmniTact, a novel tactile sensor that uses multi-camera gel imaging to enable multi-directional, high-resolution touch sensing on robotic fingertips.
• The paper's experimental evaluation shows OmniTact outperforms traditional sensors, achieving an 80% success rate in an electrical connector insertion task.
• The paper highlights future advancements in scalable manufacturing and refined signal processing to further enhance robotic manipulation capabilities.

Overview of OmniTact Sensor for Robotic Manipulation

The paper "OmniTact: A Multi-Directional High-Resolution Touch Sensor" introduces a novel tactile sensor designed to enhance robotic manipulation capabilities through multi-directional high-resolution touch sensing. Named OmniTact, this sensor utilizes multiple micro-cameras to detect deformations within a gel-based skin, offering significant advancements over existing tactile sensors by providing comprehensive contact state data from a robot's fingertip.

OmniTact addresses critical limitations present in contemporary tactile sensors, which either have restricted sensitive fields or deliver low spatial resolution. Unlike flat GelSight sensors, OmniTact achieves multi-directionality and high resolution by arranging multiple micro-cameras around a thumb-shaped gel coating, enabling sensory input from various angles and axes. This configuration not only retains a compact form factor suitable for robotic fingertips but also facilitates detailed and versatile task execution in robotic systems.

Experimental Evaluation and Results

The researchers evaluate OmniTact's effectiveness through two distinct tasks: estimating the angle of contact and achieving tactile control in an electrical connector insertion task. Both tasks demonstrate the sensor's advanced capabilities compared to state-of-the-art alternatives.

For angle estimation, OmniTact outperforms a flat GelSight sensor in ranges where contact with the surface occurs at oblique angles, thanks to its ability to perceive tactile information across multiple surfaces. In the electrical connector insertion task, the sensor delivers a remarkably high success rate of 80%, outperforming a multi-directional OptoForce sensor which only achieves 17% success.

Implications for Robotic Manipulation

The paper underscores OmniTact's potential to revolutionize how robots perceive and interact with their environment during manipulation tasks. The sensor’s capacity for high-resolution, multi-directional data acquisition enables robots to perform delicate and complex manipulation tasks with increased precision and reliability. This advancement is particularly crucial for applications requiring nuanced tactile feedback, such as assembly, packaging, and cautious object handling.

Furthermore, OmniTact’s design reveals promising pathways for future tactile sensor development, suggesting the integration of high-resolution optical sensing with multi-directional capabilities as key aspects of versatile tactile sensors.

Future Directions

The OmniTact sensor shifts the landscape for tactile sensing in robotics, hinting at extensive possibilities for integrating similar configurations into robotic hands and grippers. To fully leverage its potential, future research could explore scalable manufacturing techniques to reduce production costs, enabling widespread adoption of high-resolution tactile sensors in various robotic systems.

Additionally, further algorithmic developments could refine signal processing from OmniTact’s multi-camera array, augmenting the tactile perception capabilities of robots. By focusing on these areas, future advancements can continue enhancing robot manipulation precision, accommodating a widening array of real-world scenarios and tasks.

Ultimately, OmniTact offers a promising model for advanced tactile sensing, paving the way for more refined robotic manipulation capabilities in dynamic environments.