18 research outputs found
Robotic grasping via dexterous in-hand manipulation : approaches to effective bin picking
No full textDexterous in-hand manipulation refers to that the relative configuration between the object and the end-effector changes over time. Despite some significant advancements in this field, it remains a relatively understudied topic, especially for bin picking of thin objects. In this work, we propose three novel dexterous manipulation techniques for grasping thin objects: scooping, dig-grasping, and tilt-and-pivot manipulation. Scooping manipulation is executed via motion control with a minimalist rigid hardware design: a two-fingered parallel-jaw gripper with a fixed-length finger and a variable-length thumb; underactuated control or a compliant mechanism is not required. The manipulation relies on mobility analysis and requires the coordination of the entire manipulation system: the base gripper, the variable-length thumb, and a six-DOF manipulator. It suits both object picking from a flat surface and bin picking from a clutter. To circumvent the limitations of the model-based method such as the requirement for instance segmentation and pose estimation, we devise an instance-agnostic learning framework to directly predict the optimal pre-scoop gripper configuration with the RGB-D information of the bin scenario. The framework is hierarchical and triple-tiered, and is evaluated on heterogeneous clusters of both seen and unseen objects. As a novel technique complementary to scooping with regard to complete bin picking tasks, dig-grasping only suits malleable cluster, but takes less executing time. The manipulation is realized through a two-fingered gripper with asymmetric finger lengths. For picking rigid polygonal objects with large width, and those with width greater than the maximum gripper opening in particular, tilt-and-pivot manipulation was proved to be effective in achieving this. It requires the coordination of two manipulators: one is attached with a parallel-jaw gripper and the other with a fixture. We discuss the kinematics and planning of tilt-and-pivot, end-effector shape design, and the overall practicality of the manipulation technique.</p
Corrections to “Scooping Manipulation via Motion Control With a Two-Fingered Gripper and Its Application to Bin Picking†[Oct 21 6394-6401]
No full text1) Equations 1-4 on Page 6397 in [1] were incorrectly printed. The following presents the correct form of the equations: find x (1) subject to {eutation presented} (2) find x (3) subject to {eutation presented} (4) 2) The corresponding author details in [1] need correction.</p
Corrections to “Dig-Grasping via Direct Quasistatic Interaction Using Asymmetric Fingers: An Approach to Effective Bin Picking†[Apr 21 3033-3040]
No full text1) The authors of [1] would like to gratefully acknowledge the support of Hong KongRGC26209319, in addition to HongKong ITF ITS/240/17FX, ITS/018/17FP, and ITS/104/19FP already acknowledged in [1]. 2) The corresponding author details in [1] need correction. The correct corresponding author is Jungwon Seo (email: [email protected]).</p
Scooping Manipulation Via Motion Control with a Two-Fingered Gripper and Its Application to Bin Picking
No full textThis letter introduces a new method for scooping manipulation in constrained environments. The presented technique lends itself to relatively thin objects, with a large width-to-thickness ratio, which are commonly seen in many domestic and industrial tasks yet can cause considerable difficulty in handling. We present a novel approach to scooping based on a mobility analysis that leads to a new way to perform the operation via motion control with a two-fingered gripper. Our method thus expands the ways in which the manipulation of scooping can be performed, without necessitating underactuated control or a compliant mechanism. Our variable-length digit is suggested as a key facilitator for realizing the motion-controlled scooping maneuver. We present an extensive set of experiments showing the effectiveness of our approach in various scenarios featuring a constrained workspace, including bin picking from clutter.</p
Dig-Grasping via Direct Quasistatic Interaction Using Asymmetric Fingers: An Approach to Effective Bin Picking
No full textThis letter introduces a new method for simultaneously singulating and picking objects from clutter. The method can lead to effective robotic bin picking, which still remains elusive despite its importance in many industrial and domestic applications, especially for objects with a thin profile. We leverage planar quasistatic pushing manipulation as a way of standardized physical interaction between a robot and the object to pick. A gripper designed with digit asymmetry, realized as a two-fingered gripper with different finger lengths, is suggested as the key to successful singulating and picking through the controlled pushing maneuver. A detailed account of the manipulation process and design principles will be presented. An extensive set of experiments validate the effectiveness of our approach in three-dimensional bin picking tasks. Beyond picking, more complex manipulation capabilities such as autonomous pick-and-place/pack will also be presented.</p
Holographic MIMO Communications with Arbitrary Surface Placements: Near-Field LoS Channel Model and Capacity Limit
No full textEnvisioned as one of the most promising technologies, holographic
multiple-input multiple-output (H-MIMO) recently attracts notable research
interests for its great potential in expanding wireless possibilities and
achieving fundamental wireless limits. Empowered by the nearly continuous,
large and energy-efficient surfaces with powerful electromagnetic (EM) wave
control capabilities, H-MIMO opens up the opportunity for signal processing in
a more fundamental EM-domain, paving the way for realizing holographic imaging
level communications in supporting the extremely high spectral efficiency and
energy efficiency in future networks. In this article, we try to implement a
generalized EM-domain near-field channel modeling and study its capacity limit
of point-to-point H-MIMO systems that equips arbitrarily placed surfaces in a
line-of-sight (LoS) environment. Two effective and computational-efficient
channel models are established from their integral counterpart, where one is
with a sophisticated formula but showcases more accurate, and another is
concise with a slight precision sacrifice. Furthermore, we unveil the capacity
limit using our channel model, and derive a tight upper bound based upon an
elaborately built analytical framework. Our result reveals that the capacity
limit grows logarithmically with the product of transmit element area, receive
element area, and the combined effects of , ,
and over all transmit and receive antenna elements, where
indicates the distance between each transmit and receive elements.
Numerical evaluations validate the effectiveness of our channel models, and
showcase the slight disparity between the upper bound and the exact capacity,
which is beneficial for predicting practical system performance.Comment: double column, 17 pages, 13 figures, accepted by IEEE Journal on
Selected Areas in Communication
A Transmit-Receive Parameter Separable Electromagnetic Channel Model for LoS Holographic MIMO
No full textInternational audienceTo support the extremely high spectral efficiency and energy efficiency requirements, and emerging applications of future wireless communications, holographic multiple-input multiple-output (H-MIMO) technology is envisioned as one of the most promising enablers. It can potentially bring extra degrees-of-freedom for communications and signal processing, including spatial multiplexing in line-of-sight (LoS) channels and electromagnetic (EM) field processing performed using specialized devices, to attain the fundamental limits of wireless communications. In this context, EM-domain channel modeling is critical to harvest the benefits offered by H-MIMO. Existing EM-domain channel models are built based on the tensor Green function, which require prior knowledge of the global position and/or the relative distances and directions of the transmit/receive antenna elements. Such knowledge may be difficult to acquire in real-world applications due to extensive measurements needed for obtaining this data. To overcome this limitation, we propose a transmit-receive parameter separable channel model method-ology in which the EM-domain (or holographic) channel can be simply acquired from the distance/direction measured between the center-points between the transmit and receive surfaces, and the local positions between the transmit and receive elements, thus avoiding extensive global parameter measurements. Analysis and numerical results showcase the effectiveness of the proposed channel modeling approach in approximating the H-MIMO channel, and achieving the theoretical channel capacity
Picking Thin Objects by Tilt-and-Pivot Manipulation and Its Application to Bin Picking
No full textThis paper introduces the technique of tilt-andpivot manipulation, a new method for picking thin, rigid objects lying on a flat surface through robotic dexterous in-hand manipulation. During the manipulation process, the gripper is controlled to reorient about the contact with the object such that its finger can get in the space between the object and the supporting surface, which is formed by tilting up the object, with no relative sliding motion at the contact. As a result, a pinch grasp can be obtained on the faces of the thin object with ease. We discuss issues regarding the kinematics and planning of tilt-and-pivot, effector shape design, and the overall practicality of the manipulation technique, which is general enough to be applicable to any rigid convex polygonal objects. We also present a set of experiments in a range of bin picking scenarios.</p
A Transmit-Receive Parameter Separable Electromagnetic Channel Model for LoS Holographic MIMO
No full textTo support the extremely high spectral efficiency and energy efficiency
requirements, and emerging applications of future wireless communications,
holographic multiple-input multiple-output (H-MIMO) technology is envisioned as
one of the most promising enablers. It can potentially bring extra
degrees-of-freedom for communications and signal processing, including spatial
multiplexing in line-of-sight (LoS) channels and electromagnetic (EM) field
processing performed using specialized devices, to attain the fundamental
limits of wireless communications. In this context, EM-domain channel modeling
is critical to harvest the benefits offered by H-MIMO. Existing EM-domain
channel models are built based on the tensor Green function, which require
prior knowledge of the global position and/or the relative distances and
directions of the transmit/receive antenna elements. Such knowledge may be
difficult to acquire in real-world applications due to extensive measurements
needed for obtaining this data. To overcome this limitation, we propose a
transmit-receive parameter separable channel model methodology in which the
EM-domain (or holographic) channel can be simply acquired from the
distance/direction measured between the center-points between the transmit and
receive surfaces, and the local positions between the transmit and receive
elements, thus avoiding extensive global parameter measurements. Analysis and
numerical results showcase the effectiveness of the proposed channel modeling
approach in approximating the H-MIMO channel, and achieving the theoretical
channel capacity.Comment: Double column, 6 pages, 3 figures, 1 table, accepted by 2023 IEEE
Global Communications Conference (GLOBECOM 2023
