302 research outputs found
Autonomy Infused Teleoperation with Application to BCI Manipulation
Robot teleoperation systems face a common set of challenges including
latency, low-dimensional user commands, and asymmetric control inputs. User
control with Brain-Computer Interfaces (BCIs) exacerbates these problems
through especially noisy and erratic low-dimensional motion commands due to the
difficulty in decoding neural activity. We introduce a general framework to
address these challenges through a combination of computer vision, user intent
inference, and arbitration between the human input and autonomous control
schemes. Adjustable levels of assistance allow the system to balance the
operator's capabilities and feelings of comfort and control while compensating
for a task's difficulty. We present experimental results demonstrating
significant performance improvement using the shared-control assistance
framework on adapted rehabilitation benchmarks with two subjects implanted with
intracortical brain-computer interfaces controlling a seven degree-of-freedom
robotic manipulator as a prosthetic. Our results further indicate that shared
assistance mitigates perceived user difficulty and even enables successful
performance on previously infeasible tasks. We showcase the extensibility of
our architecture with applications to quality-of-life tasks such as opening a
door, pouring liquids from containers, and manipulation with novel objects in
densely cluttered environments
Reinforcement Learning-based Virtual Fixtures for Teleoperation of Hydraulic Construction Machine
The utilization of teleoperation is a crucial aspect of the construction
industry, as it enables operators to control machines safely from a distance.
However, remote operation of these machines at a joint level using individual
joysticks necessitates extensive training for operators to achieve proficiency
due to their multiple degrees of freedom. Additionally, verifying the machine
resulting motion is only possible after execution, making optimal control
challenging. In addressing this issue, this study proposes a reinforcement
learning-based approach to optimize task performance. The control policy
acquired through learning is used to provide instructions on efficiently
controlling and coordinating multiple joints. To evaluate the effectiveness of
the proposed framework, a user study is conducted with a Brokk 170 construction
machine by assessing its performance in a typical construction task involving
inserting a chisel into a borehole. The effectiveness of the proposed framework
is evaluated by comparing the performance of participants in the presence and
absence of virtual fixtures. This study results demonstrate the proposed
framework potential in enhancing the teleoperation process in the construction
industry
Evaluation of haptic guidance virtual fixtures and 3D visualization methods in telemanipulationâa user study
© 2019, The Author(s). This work presents a user-study evaluation of various visual and haptic feedback modes on a real telemanipulation platform. Of particular interest is the potential for haptic guidance virtual fixtures and 3D-mapping techniques to enhance efficiency and awareness in a simple teleoperated valve turn task. An RGB-Depth camera is used to gather real-time color and geometric data of the remote scene, and the operator is presented with either a monocular color video stream, a 3D-mapping voxel representation of the remote scene, or the ability to place a haptic guidance virtual fixture to help complete the telemanipulation task. The efficacy of the feedback modes is then explored experimentally through a user study, and the different modes are compared on the basis of objective and subjective metrics. Despite the simplistic task and numerous evaluation metrics, results show that the haptic virtual fixture resulted in significantly better collision avoidance compared to 3D visualization alone. Anticipated performance enhancements were also observed moving from 2D to 3D visualization. Remaining comparisons lead to exploratory inferences that inform future direction for focused and statistically significant studies
Decision-making model for adaptive impedance control of teleoperation systems
© 2008-2011 IEEE. This paper presents a haptic assistance strategy for teleoperation that makes a task and situation-specific compromise between improving tracking performance or human-machine interaction in partially structured environments via the scheduling of the parameters of an admittance controller. The proposed assistance strategy builds on decision-making models and combines one of them with impedance control techniques that are standard in bilateral teleoperation systems. Even though several decision-making models have been proposed in cognitive science, their application to assisted teleoperation and assisted robotics has hardly been explored yet. Experimental data supports the Drift-Diffusion model as a suitable scheduling strategy for haptic shared control, in which the assistance mechanism can be adapted via the parameters of reward functions. Guidelines to tune the decision making model are presented. The influence of the reward structure on the realized haptic assistances is evaluated in a user study and results are compared to the no assistance and human assistance case
Comparing Alternate Modes of Teleoperation for Constrained Tasks
Teleoperation of heavy machinery in industry often requires operators to be
in close proximity to the plant and issue commands on a per-actuator level
using joystick input devices. However, this is non-intuitive and makes
achieving desired job properties a challenging task requiring operators to
complete extensive and costly training. Despite this, operator fatigue is
common with implications for personal safety, project timeliness, cost, and
quality. While full automation is not yet achievable due to unpredictability
and the dynamic nature of the environment and task, shared control paradigms
allow operators to issue high-level commands in an intuitive, task-informed
control space while having the robot optimize for achieving desired job
properties.
In this paper, we compare a number of modes of teleoperation, exploring both
the number of dimensions of the control input as well as the most intuitive
control spaces. Our experimental evaluations of the performance metrics were
based on quantifying the difficulty of tasks based on the well known Fitts' law
as well as a measure of how well constraints affecting the task performance
were met. Our experiments show that higher performance is achieved when humans
submit commands in low-dimensional task spaces as opposed to joint space
manipulations
Cutaneous Force Feedback as a Sensory Subtraction Technique in Haptics
A novel sensory substitution technique is presented. Kinesthetic and
cutaneous force feedback are substituted by cutaneous feedback (CF) only,
provided by two wearable devices able to apply forces to the index finger and
the thumb, while holding a handle during a teleoperation task. The force
pattern, fed back to the user while using the cutaneous devices, is similar, in
terms of intensity and area of application, to the cutaneous force pattern
applied to the finger pad while interacting with a haptic device providing both
cutaneous and kinesthetic force feedback. The pattern generated using the
cutaneous devices can be thought as a subtraction between the complete haptic
feedback (HF) and the kinesthetic part of it. For this reason, we refer to this
approach as sensory subtraction instead of sensory substitution. A needle
insertion scenario is considered to validate the approach. The haptic device is
connected to a virtual environment simulating a needle insertion task.
Experiments show that the perception of inserting a needle using the
cutaneous-only force feedback is nearly indistinguishable from the one felt by
the user while using both cutaneous and kinesthetic feedback. As most of the
sensory substitution approaches, the proposed sensory subtraction technique
also has the advantage of not suffering from stability issues of teleoperation
systems due, for instance, to communication delays. Moreover, experiments show
that the sensory subtraction technique outperforms sensory substitution with
more conventional visual feedback (VF)
- âŠ