418 research outputs found
Active Clothing Material Perception using Tactile Sensing and Deep Learning
Humans represent and discriminate the objects in the same category using
their properties, and an intelligent robot should be able to do the same. In
this paper, we build a robot system that can autonomously perceive the object
properties through touch. We work on the common object category of clothing.
The robot moves under the guidance of an external Kinect sensor, and squeezes
the clothes with a GelSight tactile sensor, then it recognizes the 11
properties of the clothing according to the tactile data. Those properties
include the physical properties, like thickness, fuzziness, softness and
durability, and semantic properties, like wearing season and preferred washing
methods. We collect a dataset of 153 varied pieces of clothes, and conduct 6616
robot exploring iterations on them. To extract the useful information from the
high-dimensional sensory output, we applied Convolutional Neural Networks (CNN)
on the tactile data for recognizing the clothing properties, and on the Kinect
depth images for selecting exploration locations. Experiments show that using
the trained neural networks, the robot can autonomously explore the unknown
clothes and learn their properties. This work proposes a new framework for
active tactile perception system with vision-touch system, and has potential to
enable robots to help humans with varied clothing related housework.Comment: ICRA 2018 accepte
Proprioceptive Learning with Soft Polyhedral Networks
Proprioception is the "sixth sense" that detects limb postures with motor
neurons. It requires a natural integration between the musculoskeletal systems
and sensory receptors, which is challenging among modern robots that aim for
lightweight, adaptive, and sensitive designs at a low cost. Here, we present
the Soft Polyhedral Network with an embedded vision for physical interactions,
capable of adaptive kinesthesia and viscoelastic proprioception by learning
kinetic features. This design enables passive adaptations to omni-directional
interactions, visually captured by a miniature high-speed motion tracking
system embedded inside for proprioceptive learning. The results show that the
soft network can infer real-time 6D forces and torques with accuracies of
0.25/0.24/0.35 N and 0.025/0.034/0.006 Nm in dynamic interactions. We also
incorporate viscoelasticity in proprioception during static adaptation by
adding a creep and relaxation modifier to refine the predicted results. The
proposed soft network combines simplicity in design, omni-adaptation, and
proprioceptive sensing with high accuracy, making it a versatile solution for
robotics at a low cost with more than 1 million use cycles for tasks such as
sensitive and competitive grasping, and touch-based geometry reconstruction.
This study offers new insights into vision-based proprioception for soft robots
in adaptive grasping, soft manipulation, and human-robot interaction.Comment: 20 pages, 10 figures, 2 tables, submitted to the International
Journal of Robotics Research for revie
Objekt-Manipulation und Steuerung der Greifkraft durch Verwendung von Taktilen Sensoren
This dissertation describes a new type of tactile sensor and an improved version of the dynamic tactile sensing approach that can provide a regularly updated and accurate estimate of minimum applied forces for use in the control of gripper manipulation. The pre-slip sensing algorithm is proposed and implemented into two-finger robot gripper. An algorithm that can discriminate between types of contact surface and recognize objects at the contact stage is also proposed. A technique for recognizing objects using tactile sensor arrays, and a method based on the quadric surface parameter for classifying grasped objects is described. Tactile arrays can recognize surface types on contact, making it possible for a tactile system to recognize translation, rotation, and scaling of an object independently.Diese Dissertation beschreibt eine neue Art von taktilen Sensoren und einen verbesserten Ansatz zur dynamischen Erfassung von taktilen daten, der in regelmĂ€Ăigen ZeitabstĂ€nden eine genaue Bewertung der minimalen Greifkraft liefert, die zur Steuerung des Greifers nötig ist. Ein Berechnungsverfahren zur Voraussage des Schlupfs, das in einen Zwei-Finger-Greifarm eines Roboters eingebaut wurde, wird vorgestellt. Auch ein Algorithmus zur Unterscheidung von verschiedenen OberflĂ€chenarten und zur Erkennung von Objektformen bei der BerĂŒhrung wird vorgestellt. Ein Verfahren zur Objekterkennung mit Hilfe einer Matrix aus taktilen Sensoren und eine Methode zur Klassifikation ergriffener Objekte, basierend auf den Daten einer rechteckigen OberflĂ€che, werden beschrieben. Mit Hilfe dieser Matrix können unter schiedliche Arten von OberflĂ€chen bei BerĂŒhrung erkannt werden, was es fĂŒr das Tastsystem möglich macht, Verschiebung, Drehung und GröĂe eines Objektes unabhĂ€ngig voneinander zu erkennen
Doctor of Philosophy
dissertationTactile sensors are a group of sensors that are widely being developed for transduction of touch, force and pressure in the field of robotics, contact sensing and gait analysis. These sensors are employed to measure and register interactions between contact surfaces and the surrounding environment. Since these sensors have gained usage in the field of robotics and gait analysis, there is a need for these sensors to be ultra flexible, highly reliable and capable of measuring pressure and two-axial shear simultaneously. The sensors that are currently available are not capable of achieving all the aforementioned qualities. The goal of this work is to design and develop such a flexible tactile sensor array based on a capacitive sensing scheme and we call it the flexible tactile imager (FTI). The developed design can be easily multiplexed into a high-density array of 676 multi-fingered capacitors that are capable of measuring pressure and two-axial shear simultaneously while maintaining sensor flexibility and reliability. The sensitivity of normal and shear stress for the FTI are 0.74/MPa and 79.5/GPa, respectively, and the resolvable displacement and velocity are as low as 60 ”m and 100 ”m/s, respectively. The developed FTI demonstrates the ability to detect pressure and shear contours of objects rolling on top of it and capability to measure microdisplacement and microvelocities that are desirable during gait analysis
More Than a Feeling: Learning to Grasp and Regrasp using Vision and Touch
For humans, the process of grasping an object relies heavily on rich tactile
feedback. Most recent robotic grasping work, however, has been based only on
visual input, and thus cannot easily benefit from feedback after initiating
contact. In this paper, we investigate how a robot can learn to use tactile
information to iteratively and efficiently adjust its grasp. To this end, we
propose an end-to-end action-conditional model that learns regrasping policies
from raw visuo-tactile data. This model -- a deep, multimodal convolutional
network -- predicts the outcome of a candidate grasp adjustment, and then
executes a grasp by iteratively selecting the most promising actions. Our
approach requires neither calibration of the tactile sensors, nor any
analytical modeling of contact forces, thus reducing the engineering effort
required to obtain efficient grasping policies. We train our model with data
from about 6,450 grasping trials on a two-finger gripper equipped with GelSight
high-resolution tactile sensors on each finger. Across extensive experiments,
our approach outperforms a variety of baselines at (i) estimating grasp
adjustment outcomes, (ii) selecting efficient grasp adjustments for quick
grasping, and (iii) reducing the amount of force applied at the fingers, while
maintaining competitive performance. Finally, we study the choices made by our
model and show that it has successfully acquired useful and interpretable
grasping behaviors.Comment: 8 pages. Published on IEEE Robotics and Automation Letters (RAL).
Website: https://sites.google.com/view/more-than-a-feelin
Development and Integration of Tactile Sensing System
To grasp and manipulate complex objects, robots require information about
the interaction between the end effector and the object. This work describes the
integration of a low-cost 3-axis tactile sensing system into two different robotic
systems and the measurement of some of these complex interactions. The sensor
itself is small, lightweight, and compliant so that it can be integrated within a variety
of end effectors and locations on those end effectors (e.g. wrapped around a finger).
To improve usability and data collection, a custom interface board and ROS (Robot
Operating System) package were developed to read the sensor data and interface
with the robots and grippers. Sensor data has been collected from four different
tasks: 1. pick and place of non-conductive and conductive objects, 2. wrist-based
manipulation, 3. peeling tape, and 4. human interaction with a grasped object. In
the last task, a closed loop controller is used to adjust the grip force on the grasped
object while the human interacts with it
Tactile force-sensing for dynamic gripping using piezoelectric force- sensors
Thesis (M. Tech.) -- Central University of Technology, Free State, 200
Tactile Sensing for Robotic Applications
This chapter provides an overview of tactile sensing in robotics. This chapter is an attempt
to answer three basic questions:
\u2022 What is meant by Tactile Sensing?
\u2022 Why Tactile Sensing is important?
\u2022 How Tactile Sensing is achieved?
The chapter is organized to sequentially provide the answers to above basic questions.
Tactile sensing has often been considered as force sensing, which is not wholly true. In order
to clarify such misconceptions about tactile sensing, it is defined in section 2. Why tactile
section is important for robotics and what parameters are needed to be measured by tactile
sensors to successfully perform various tasks, are discussed in section 3. An overview of
`How tactile sensing has been achieved\u2019 is given in section 4, where a number of
technologies and transduction methods, that have been used to improve the tactile sensing
capability of robotic devices, are discussed. Lack of any tactile analog to Complementary
Metal Oxide Semiconductor (CMOS) or Charge Coupled Devices (CCD) optical arrays has
often been cited as one of the reasons for the slow development of tactile sensing vis-\ue0-vis
other sense modalities like vision sensing. Our own contribution \u2013 development of tactile
sensing arrays using piezoelectric polymers and involving silicon micromachining - is an
attempt in the direction of achieving tactile analog of CMOS optical arrays. The first phase
implementation of these tactile sensing arrays is discussed in section 5. Section 6 concludes
the chapter with a brief discussion on the present status of tactile sensing and the challenges
that remain to be solved
- âŠ