67 research outputs found
Modelling Social Interaction between Humans and Service Robots in Large Public Spaces
With the advent of service robots in public places (e.g., in airports and shopping malls), understanding socio-psychological interactions between humans and robots is of paramount importance. On the one hand, traditional robotic navigation systems consider humans and robots as moving obstacles and focus on the problem of real-time collision avoidance in Human-Robot Interaction (HRI) using mathematical models. On the other hand, the behavior of a robot has been determined with respect to a human. Parameters for human-human interaction have been assumed and applied to interactions involving robots. One major limitation is the lack of sufficient data for calibration and validation procedures. This paper models, calibrates and validates the socio-psychological interaction of the human in HRIs among crowds. The mathematical model is an extension of the Social Force Model for crowd modelling. The proposed model is calibrated and validated using open source datasets (including uninstructed human trajectories) from the Asia and Pacific Trade Center shopping mall in Osaka (Japan).In summary, the results of the calibration and validation on the multiple HRIs encountered in the datasets show that humans react to a service robot to a higher extend within a larger distance compared to the interaction range towards another human. This microscopic model, calibration and validation framework can be used to simulate HRI between service robots and humans, predict humans' behavior, conduct comparative studies, and gain insights into safe and comfortable human-robot relationships from the human's perspective
Adaptive Underactuated Finger with Active Rolling Surface
This paper presents the design, prototype and kinematic model of a new adaptive underactuated finger with an
articulated skin/surface that is able to bend and, at the same
time, provides active rolling motion along its central axis while
keeping the finger configuration. The design is based on a planar
chain of overlapping spherical phalanxes that are tendon-driven.
The finger has an articulated surface made of an external chain
of hollow universal joints that can rotate via its central axis
on the surface of the internal structure. The outer surface
provides a second active Degree of Freedom (DoF). The two
actuators, driving the bending and/or rolling motion, can be
used independently. A set of experiments have been included to
validate and measure the performance of the prototype for the
grasping and rolling actions. The proposed finger can be built
with a different number of phalanxes and sizes. A number of
these fingers can be arranged along a palm structure resulting
in a multi-finger robotic grasper for applications that require
adaptation and in-hand manipulation capabilities such as pHRI
A Caging Inspired Gripper using Flexible Fingers and a Movable Palm
This paper proposes the design of a robotic
gripper motivated by the bin-picking problem, where a variety
of objects need to be picked from cluttered bins. The presented
gripper design focuses on an enveloping cage-like approach,
which surrounds the object with three hooked fingers, and
then presses into the object with a movable palm. The fingers
are flexible and imbue grasps with some elasticity, helping to
conform to objects and, crucially, adding friction to cases where
an object cannot be caged. This approach proved effective on
a set of basic shapes, such as cuboids and cylinders, in which
every object could be grasped. In particular, flat bottom parts
could be grasped in a very stable manner, as demonstrated by
testing grasps with multiple 5N and 10N disturbances. A set
of supermarket items were also tested, highlighting promising
features such as effective grasping of fruits and vegetables, as
well as some limitations in the current embodiment, which is
not always able to slip the fingers underneath objects
Soft fluidic rotary actuator with improved actuation properties
The constantly increasing amount of machines operating in the vicinity of humans makes it necessary to rethink the design approach for such machines to ensure that they are safe when interacting with humans. Traditional mechanisms are rigid and heavy and as such considered unsuitable, even dangerous when a controlled physical contact with humans is desired. A huge improvement in terms of safe human-robot interaction has been achieved by a radically new approach to robotics - soft material robotics. These new robots are made of compliant materials that render them safe when compared to the conventional rigid-link robots. This undeniable advantage of compliance and softness is paired with a number of drawbacks. One of them is that a complex and sophisticated controller is required to move a soft robot into the desired positions or along a desired trajectory, especially with external forces being present. In this paper we propose an improved soft fluidic rotary actuator composed of silicone rubber and fiber-based reinforcement. The actuator is cheap and easily manufactured providing near linear actuation properties when compared to pneumatic actuators presented elsewhere. The paper presents the actuator design, manufacturing process and a mathematical model of the actuator behavior as well as an experimental validation of the model. Four different actuator types are compared including a square-shaped and three differently reinforced cylindrical actuators
Correlation between Situational Awareness and EEG signals
An important aspect in safety–critical domains is Situational Awareness (SA) where operators consolidate
data into an understanding of the situation that needs to be updated dynamically as the situation changes
over time. Among existing measures of SA, only physiological measures can assess the cognitive processes associated with SA in real-time. Some studies showed promise in detecting cognitive states associated with SA in complex tasks using brain signals (e.g. electroencephalogram/EEG). In this paper, an
analytical methodology is proposed to identify EEG signatures associated with SA on various regions of
the brain. A new data set from 32 participants completing the SA test in the PEBL is collected using a
32-channel dry-EEG headset. The proposed method is tested on the new data set and a correlation is
identified between the frequency bands of b (12 - 30 Hz) and c (30 - 45 Hz) and SA. Also, activation of
neurons in the left and right hemisphere of the parietal and temporal lobe is observed. These regions
are responsible for the visuo-spatial ability and memory and reasoning tasks. Among the presented
results, the highest achieved accuracy on test data is 67%
Dynamic modelling and visco-elastic parameter identification of a fibre-reinforced soft fluidic elastomer manipulator
A dynamic model of a soft fibre-reinforced fluidic elastomer is presented and experimentally verified, which
can be used for model-based controller design. Due to the
inherent visco-(hyper)elastic characteristics and nonlinear timedependent behaviour of soft fluidic elastomer robots, analytic
dynamic modelling is challenging. The fibre reinforced noninflatable soft fluidic elastomer robot used in this paper can produce both planar and spatial movements. Dynamic equations
are developed for both cases. Parameters, related to the viscoelastic behaviour of the robot during elongation and bending
motion, are identified experimentally and incorporated into
our model. The modified dynamic model is then validated in
experiments comparing the time responses of the physical robot
with the corresponding outputs of the simulation model. The
results validate the accuracy of the proposed dynamic model
A model for in vitro evaluation of overlapping connections between devices used in the endovascular repair of popliteal aneurysms
This work proposes a new methodology to investigate the potential for disconnection (Type III
endoleak) of pairs of overlapped endoprostheses in a popliteal model vessel after a cyclic
physiologic load, for three different overlap lengths. A multiaxial fatigue accelerated testing
was designed to mimic the physiological loads and movements to which the peripheral arteries
are submitted during gait. The experiment design was based on principles from technical
standards ASTM F2477-07 and ASTM F2942-13. Migration and disconnection were
monitored by DIC (Digital Image Correlation) for three different overlap lengths (20, 30 and
40mm). The testing method proposed in this work was efficient to provide a simulated
environment to evaluate the influence of gait biomechanics on overlapped endoprosthesis
disconnection. Obtained results demonstrated minimal or absence of relevant migration
between the endoprosthesis, range -0.06 to 0,34 millimeters. The proposed methodology was
verified as a valuable tool to investigate the influence of the biomechanical environment which
the devices are subjected to on the migration of overlapped endoprosthesis. It may become a
new alternative to study the pre-clinical in vitro performance of single endoprosthesis or
multiple connected devices with different overlapped regions
Real-Time Pose Esti ation and Obstacle Avoidance for Multi-segment Continuum Manipulator in Dynamic Environments
In this paper, we present a novel pose estimation and obstacle avoidance approach for tendon-driven multi-segment continuum manipulators moving in dynamic environments. A novel multi-stage implementation of an Extended Kalman Filter is used to estimate the pose of every point along the manipulator's body using only the position information of each segment tip. Combined with a potential field, the overall algorithm will guide the manipulator tip to a desired target location and, at the same time, keep the manipulator body safe from collisions with obstacles. The results show that the approach works well in a real-time simulation environment that contains moving obstacles in the vicinity of the manipulator
Three-Axis Fiber-Optic Body Force Sensor for Flexible Manipulators
This paper proposes a force/torque sensor structure that can be easily integrated into a flexible manipulator structure. The sensor's ring-like structure with its hollow inner section provides ample space for auxiliary components, such as cables and tubes, to be passed through and, hence, is very suitable for integration with tendon-driven and fluid-actuated manipulators. The sensor structure can also accommodate the wiring for a distributed sensor system as well as for diagnostic instruments that may be incorporated in the manipulator. Employing a sensing approach based on optical fibers as done here allows for the creation of sensors that are free of electrical currents at the point of sensing and immune to magnetic fields. These sensors are inherently safe when used in the close vicinity of humans and their measuring performance is not impaired when they are operated in or nearby machines, such as magnetic resonance imaging scanners. This type of sensor concept is particularly suitable for inclusion in instruments and robotic tools for minimally invasive surgery. This paper summarizes the design, integration challenges, and calibration of the proposed optical three-axis force sensor. The experimental results confirm the effectiveness of our optical sensing approach and show that after calibrating its stiffness matrix, force and momentum components can be determined accurately
Control Design for Interval Type-2 Fuzzy Systems Under Imperfect Premise Matching
Abstract—This paper focuses on designing interval type-2 (IT2)
control for nonlinear systems subject to parameter uncertainties.
To facilitate the stability analysis and control synthesis, an IT2 TS
fuzzy model is employed to represent the dynamics of nonlinear
systems of which the parameter uncertainties are captured by
IT2 membership functions characterized by the lower and upper
membership functions. A novel IT2 fuzzy controller is proposed
to perform the control process, where the membership functions
and number of rules can be freely chosen and different from
those of the IT2 T-S fuzzy model. Consequently, the IT2 fuzzymodel-
based (FMB) control system is with imperfectly matched
membership functions, which hinders the stability analysis. To
relax the stability analysis for this class of IT2 FMB control
systems, the information of footprint of uncertainties, and the
lower and upper membership functions are taken into account
for the stability analysis. Based on the Lyapunov stability theory,
some stability conditions in terms of linear matrix inequalities
are obtained to determine the system stability and achieve the
control design. Finally, simulation and experimental examples
are provided to demonstrate the effectiveness and the merit of
the proposed approach
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