1,980 research outputs found
Trajectory Deformations from Physical Human-Robot Interaction
Robots are finding new applications where physical interaction with a human
is necessary: manufacturing, healthcare, and social tasks. Accordingly, the
field of physical human-robot interaction (pHRI) has leveraged impedance
control approaches, which support compliant interactions between human and
robot. However, a limitation of traditional impedance control is that---despite
provisions for the human to modify the robot's current trajectory---the human
cannot affect the robot's future desired trajectory through pHRI. In this
paper, we present an algorithm for physically interactive trajectory
deformations which, when combined with impedance control, allows the human to
modulate both the actual and desired trajectories of the robot. Unlike related
works, our method explicitly deforms the future desired trajectory based on
forces applied during pHRI, but does not require constant human guidance. We
present our approach and verify that this method is compatible with traditional
impedance control. Next, we use constrained optimization to derive the
deformation shape. Finally, we describe an algorithm for real time
implementation, and perform simulations to test the arbitration parameters.
Experimental results demonstrate reduction in the human's effort and
improvement in the movement quality when compared to pHRI with impedance
control alone
On inferring intentions in shared tasks for industrial collaborative robots
Inferring human operators' actions in shared collaborative tasks, plays a crucial role in enhancing the cognitive capabilities of industrial robots. In all these incipient collaborative robotic applications, humans and robots not only should share space but also forces and the execution of a task. In this article, we present a robotic system which is able to identify different human's intentions and to adapt its behavior consequently, only by means of force data. In order to accomplish this aim, three major contributions are presented: (a) force-based operator's intent recognition, (b) force-based dataset of physical human-robot interaction and (c) validation of the whole system in a scenario inspired by a realistic industrial application. This work is an important step towards a more natural and user-friendly manner of physical human-robot interaction in scenarios where humans and robots collaborate in the accomplishment of a task.Peer ReviewedPostprint (published version
Collision Detection and Reaction: A Contribution to Safe Physical Human-Robot Interaction
In the framework of physical Human-Robot Interaction
(pHRI), methodologies and experimental tests are
presented for the problem of detecting and reacting to collisions
between a robot manipulator and a human being. Using a
lightweight robot that was especially designed for interactive
and cooperative tasks, we show how reactive control strategies
can significantly contribute to ensuring safety to the human
during physical interaction. Several collision tests were carried
out, illustrating the feasibility and effectiveness of the proposed
approach. While a subjective “safety” feeling is experienced by
users when being able to naturally stop the robot in autonomous
motion, a quantitative analysis of different reaction strategies
was lacking. In order to compare these strategies on an objective
basis, a mechanical verification platform has been built. The
proposed collision detection and reactions methods prove to
work very reliably and are effective in reducing contact forces
far below any level which is dangerous to humans. Evaluations
of impacts between robot and human arm or chest up to a
maximum robot velocity of 2.7 m/s are presented
Sensorless Physical Human-robot Interaction Using Deep-Learning
Physical human-robot interaction has been an area of interest for decades.
Collaborative tasks, such as joint compliance, demand high-quality joint torque
sensing. While external torque sensors are reliable, they come with the
drawbacks of being expensive and vulnerable to impacts. To address these
issues, studies have been conducted to estimate external torques using only
internal signals, such as joint states and current measurements. However,
insufficient attention has been given to friction hysteresis approximation,
which is crucial for tasks involving extensive dynamic to static state
transitions. In this paper, we propose a deep-learning-based method that
leverages a novel long-term memory scheme to achieve dynamics identification,
accurately approximating the static hysteresis. We also introduce modifications
to the well-known Residual Learning architecture, retaining high accuracy while
reducing inference time. The robustness of the proposed method is illustrated
through a joint compliance and task compliance experiment.Comment: 7 pages, ICRA 2024 Submissio
Adaptive Optimal Control in Physical Human-Robot Interaction
abstract: What if there is a way to integrate prosthetics seamlessly with the human body and robots could help improve the lives of children with disabilities? With physical human-robot interaction being seen in multiple aspects of life, including industry, medical, and social, how these robots are interacting with human becomes even more important. Therefore, how smoothly the robot can interact with a person will determine how safe and efficient this relationship will be. This thesis investigates adaptive control method that allows a robot to adapt to the human's actions based on the interaction force. Allowing the relationship to become more effortless and less strained when the robot has a different goal than the human, as seen in Game Theory, using multiple techniques that adapts the system. Few applications this could be used for include robots in physical therapy, manufacturing robots that can adapt to a changing environment, and robots teaching people something new like dancing or learning how to walk after surgery.
The experience gained is the understanding of how a cost function of a system works, including the tracking error, speed of the system, the robot’s effort, and the human’s effort. Also, this two-agent system, results into a two-agent adaptive impedance model with an input for each agent of the system. This leads to a nontraditional linear quadratic regulator (LQR), that must be separated and then added together. Thus, creating a traditional LQR. This new experience can be used in the future to help build better safety protocols on manufacturing robots. In the future the knowledge learned from this research could be used to develop technologies for a robot to allow to adapt to help counteract human error.Dissertation/ThesisMasters Thesis Engineering 201
Differential game theory for versatile physical human-robot interaction
The last decades have seen a surge of robots working in contact with humans. However, until now these contact robots have made little use of the opportunities offered by physical interaction and lack a systematic methodology to produce versatile behaviours. Here, we develop an interactive robot controller able to understand the control strategy of the human user and react optimally to their movements. We demonstrate that combining an observer with a differential game theory controller can induce a stable interaction between the two partners, precisely identify each other’s control law, and allow them to successfully perform the task with minimum effort. Simulations and experiments with human subjects demonstrate these properties and illustrate how this controller can induce different representative interaction strategies
Toward Effective Physical Human-Robot Interaction
With the fast advancement of technology, in recent years, robotics technology has significantly matured and produced robots that are able to operate in unstructured environments such as domestic environments, offices, hospitals and other human-inhabited locations. In this context, the interaction and cooperation between humans and robots has become an important and challenging aspect of robot development. Among the various kinds of possible interactions, in this Ph.D. thesis I am particularly interested in physical human-robot interaction (pHRI). In order to study how a robot can successfully engage in physical interaction with people and which factors are crucial during this kind of interaction, I investigated how humans and robots can hand over objects to each other. To study this specific interactive task I developed two robotic prototypes and conducted human-robot user studies. Although various aspects of human-robot handovers have been deeply investigated in the state of the art, during my studies I focused on three issues that have been rarely investigated so far: Human presence and motion analysis during the interaction in order to infer non-verbal communication cues and to synchronize the robot actions with the human motion; Development and evaluation of human-aware pro-active robot behaviors that enable robots to behave actively in the proximity of the human body in order to negotiate the handover location and to perform the transfer of the object; Consideration of objects grasp affordances during the handover in order to make the interaction more comfortable for the human
- …