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On the Existence of Flight Equilibria in Longitudinal Dynamics [article]

Daniele Pucci
2019 arXiv   pre-print
Any control law for aircraft asymptotic stabilization requires the existence of an equilibrium condition, also called trim flight condition. At a constant velocity flight, for instance, there must exist an aircraft orientation such that aerodynamic forces oppose the plane's thrust plus weight, and the torque balance equals zero. A closer look at the equations characterizing the trim conditions point out that the existence of aircraft equilibrium configurations cannot be in general claimed
more » ... hand. By considering aircraft longitudinal linear dynamics, this paper shows that the existence of flight trim conditions is a consequence of the vehicle shape or aerodynamics. These results are obtained independently from the aircraft flight envelope, and do not require any explicit expression of the aerodynamics acting on the vehicle.
arXiv:1909.06203v1 fatcat:lluislxrkbdc5cxdlh7mf5sfhi

Trajectory Advancement during Human-Robot Collaboration [article]

Yeshasvi Tirupachuri, Gabriele Nava, Lorenzo Rapetti, Claudia Latella, Daniele Pucci
2019 arXiv   pre-print
As technology advances, the barriers between the co-existence of humans and robots are slowly coming down. The prominence of physical interactions for collaboration and cooperation between humans and robots will be an undeniable fact. Rather than exhibiting simple reactive behaviors to human interactions, it is desirable to endow robots with augmented capabilities of exploiting human interactions for successful task completion. Towards that goal, in this paper, we propose a trajectory
more » ... t approach in which we mathematically derive the conditions that facilitate advancing along a reference trajectory by leveraging assistance from helpful interaction wrench present during human-robot collaboration. We validate our approach through experiments conducted with the iCub humanoid robot both in simulation and on the real robot.
arXiv:1907.13445v1 fatcat:pzvwcnkidfcddhck7bqzthxdny

Skin Normal Force Calibration Using Vacuum Bags [article]

Joan Kangro, Silvio Traversaro, Daniele Pucci, Francesco Nori
2016 arXiv   pre-print
The paper presents a proof of concept to calibrate iCub's skin using vacuum bags. The method's main idea consists in inserting the skin in a vacuum bag, and then decreasing the pressure in the bag to create a uniform pressure distribution on the skin surface. Acquisition and data processing of the bag pressure and sensors' measured capacitance allow us to characterize the relationship between the pressure and the measured capacitance of each sensor. After calibration, integration of the
more » ... distribution over the skin geometry provides us with the net normal force applied to the skin. Experiments are conducted using the forearm skin of the iCub humanoid robot, and validation results indicate acceptable average errors in force prediction.
arXiv:1609.09720v1 fatcat:bvxxvsznejg7fforq22iasctsy

Nonlinear Feedback Control of Axisymmetric Aerial Vehicles [article]

Daniele Pucci, Tarek Hamel, Pascal Morin, Claude Samson
2014 arXiv   pre-print
We investigate the use of simple aerodynamic models for the feedback control of aerial vehicles with large flight envelopes. Thrust-propelled vehicles with a body shape symmetric with respect to the thrust axis are considered. Upon a condition on the aerodynamic characteristics of the vehicle, we show that the equilibrium orientation can be explicitly determined as a function of the desired flight velocity. This allows for the adaptation of previously proposed control design approaches based on
more » ... the thrust direction control paradigm. Simulation results conducted by using measured aerodynamic characteristics of quasi-axisymmetric bodies illustrate the soundness of the proposed approach.
arXiv:1403.5290v1 fatcat:4jg63eupqbg6vnaz4mhny2coya

Collocated Adaptive Control of Underactuated Mechanical Systems [article]

Francesco Romano and Daniele Pucci and Francesco Nori
2014 arXiv   pre-print
Collocated adaptive control of underactuated systems is still a main concern for the control community, all the more so because the collocated dynamics is no longer linear with respect to the constant base parameters. This work extends and encompasses the well known adaptive control result for fully actuated mechanical systems to the underactuated case. The key point is the introduction of a fictitious control input that allows us to consider the complete system dynamics, which is assumed to be
more » ... linear with respect to the base parameters. Local stability and convergence of time varying reference trajectories for the collocated dynamics are demonstrated by using Lyapunov and Barbalat arguments. Simulation and experimental results on a two-link manipulator verify the soundness of the proposed approach.
arXiv:1405.5005v1 fatcat:56f5bjqeebbnjmb7itbkav2tei

Momentum Control of Humanoid Robots with Series Elastic Actuators [article]

Gabriele Nava, Daniele Pucci, Francesco Nori
2017 arXiv   pre-print
Humanoid robots may require a degree of compliance at the joint level for improving efficiency, shock tolerance, and safe interaction with humans. The presence of joint elasticity, however, complexifies the design of balancing and walking controllers. This paper proposes a control framework for extending momentum based controllers developed for stiff actuators to the case of series elastic actuators. The key point is to consider the motor velocities as an intermediate control input, and then
more » ... ly high-gain control to stabilise the desired motor velocities achieving momentum control. Simulations carried out on a model of the robot iCub verify the soundness of the proposed approach.
arXiv:1703.01882v1 fatcat:wy6twjof5jbwja4qvinhnkf6dq

Towards Aerial Humanoid Robotics

Daniele Pucci, Luca Fiorio, Silvio Traversaro, Gabriele Nava, Giuseppe L'erario, Hosameldin Awadalla, Fabio Bergonti, Giorgio Metta
2019 Zenodo  
Science fiction has long inspired pioneers of new areas of Engineering. When imagination meets the current needs of civil society, creative thinking then often gets real, and projects aiming at breakthroughs for advancing the scientific state of the art are put in place. Robotics is a scientific field that has always been driven by visionary applications of Engineering, often receiving impetus from the human will of having extended locomotion and interaction capacities. The implementation of
more » ... ipulation and Locomotion on robotic platforms, however, remains a big challenge for the Robotics community. The resulting endeavor paved the way to new branches of Robotics aimed at combining Manipulation and Locomotion into single platforms. Aerial Manipulation [1], for instance, unifies Manipulation and Aerial Locomotion by conceiving robots capable of flying while manipulating an object. Humanoid Robotics [2], instead, merges Manipulation and Terrestrial Locomotion since humanoid robots can usually manipulate objects and move around by exploiting contacts with the environment (e.g. walking). This paper presents the challenges towards unifying Manipulation, Aerial, and Terrestrial Locomotion by implementing Aerial Humanoid Robotics. Aerial humanoid robots can then fly, walk, manipulate, and transport objects in the surrounding environment, thus being pivotal for disaster response and opening new branches of applications for humanoid robots. In other words, Aerial Humanoid Robotics unifies Aerial Manipulation [1] and Humanoid Robotics [2]. By doing so, aerial humanoid robots overcome the lack of terrestrial locomotion of aerial manipulators and extend the locomotion capabilities of humanoid robots to the flight case. Aerial humanoid robots can then walk, fly, manipulate and transport objects, thus offering energetically efficient solutions to payload transportation and object manipulation. In fact, a platform implementing Aerial Humanoid Robotics can reach the desired location by flying, thus avoiding challenging terrains [...]
doi:10.5281/zenodo.4814306 fatcat:amxoxqqf2rbdvcx66vhok2ma4i

Efficient Geometric Linearization of Moving-Base Rigid Robot Dynamics [article]

Martijn Bos, Silvio Traversaro, Daniele Pucci, Alessandro Saccon
2022 arXiv   pre-print
The linearization of the equations of motion of a robotics system about a given state-input trajectory, including a controlled equilibrium state, is a valuable tool for model-based planning, closed-loop control, gain tuning, and state estimation. Contrary to the case of fixed based manipulators with prismatic or rotary joints, the state space of moving-base robotic systems such as humanoids, quadruped robots, or aerial manipulators cannot be globally parametrized by a finite number of
more » ... t coordinates. This impossibility is a direct consequence of the fact that the state of these systems includes the system's global orientation, formally described as an element of the special orthogonal group SO(3). As a consequence, obtaining the linearization of the equations of motion for these systems is typically resolved, from a practical perspective, by locally parameterizing the system's attitude by means of, e.g., Euler or Cardan angles. This has the drawback, however, of introducing artificial parameterization singularities and extra derivative computations. In this contribution, we show that it is actually possible to define a notion of linearization that does not require the use of a local parameterization for the system's orientation, obtaining a mathematically elegant, recursive, and singularity-free linearization for moving-based robot systems. Recursiveness, in particular, is obtained by proposing a nontrivial modification of existing recursive algorithms to allow for computations of the geometric derivatives of the inverse dynamics and the inverse of the mass matrix of the robotic system. The correctness of the proposed algorithm is validated by means of a numerical comparison with the result obtained via geometric finite difference.
arXiv:2204.05092v1 fatcat:5ojkzy2btfd5hn5klztfwojs7q

Nonlinear feedback control of axisymmetric aerial vehicles

Daniele Pucci, Tarek Hamel, Pascal Morin, Claude Samson
2015 Automatica  
We investigate the use of simple aerodynamic models for the feedback control of underactuated aerial vehicles flying with large flight envelopes. Thrust-propelled vehicles with a body shape symmetric with respect to the thrust axis are considered. Upon a condition on the aerodynamic characteristics of the vehicle, we show that the equilibrium orientation can be explicitly determined as a function of the desired flight velocity. This allows for the adaptation of previously proposed control
more » ... approaches based on the thrust direction control paradigm. Simulation results conducted by using measured aerodynamic characteristics of quasi-axisymmetric bodies illustrate the soundness of the proposed approach.
doi:10.1016/j.automatica.2014.12.031 fatcat:kimo25fd4vc4lbrbupdo222poa

Contact Force and Joint Torque Estimation Using Skin [article]

Francisco Javier Andrade Chavez, Joan Kangro, Silvio Traversaro, Francesco Nori, Daniele Pucci
2017 arXiv   pre-print
In this paper, we present algorithms to estimate external contact forces and joint torques using only skin, i.e. distributed tactile sensors. To deal with gaps between the tactile sensors (taxels), we use interpolation techniques. The application of these interpolation techniques allows us to estimate contact forces and joint torques without the need for expensive force-torque sensors. Validation was performed using the iCub humanoid robot.
arXiv:1709.06902v1 fatcat:xl5kfs4qbneixe4qcmacibwazm

Trajectory Advancement for Robot Stand-up with Human Assistance [article]

Yeshasvi Tirupachuri, Gabriele Nava, Lorenzo Rapetti, Claudia Latella, Daniele Pucci
2019 arXiv   pre-print
Physical interactions are inevitable part of human-robot collaboration tasks and rather than exhibiting simple reactive behaviors to human interactions, collaborative robots need to be endowed with intuitive behaviors. This paper proposes a trajectory advancement approach that facilitates advancement along a reference trajectory by leveraging assistance from helpful interaction wrench present during human-robot collaboration. We validate our approach through experiments in simulation with iCub.
arXiv:1910.06786v1 fatcat:ocfd5txoznhnlgm5db7gm56itq

Dynamic Complementarity Conditions and Whole-Body Trajectory Optimization for Humanoid Robot Locomotion [article]

Stefano Dafarra, Giulio Romualdi, Daniele Pucci
2022 arXiv   pre-print
The paper presents a planner to generate walking trajectories by using the centroidal dynamics and the full kinematics of a humanoid robot. The interaction between the robot and the walking surface is modeled explicitly via new conditions, the Dynamical Complementarity Constraints. The approach does not require a predefined contact sequence and generates the footsteps automatically. We characterize the robot control objective via a set of tasks, and we address it by solving an optimal control
more » ... oblem. We show that it is possible to achieve walking motions automatically by specifying a minimal set of references, such as a constant desired center of mass velocity and a reference point on the ground. Furthermore, we analyze how the contact modelling choices affect the computational time. We validate the approach by generating and testing walking trajectories for the humanoid robot iCub.
arXiv:2207.03198v1 fatcat:hfm2utmsxza27c7ge6k5ap3pf4

Trajectory Advancement for Robot Stand-up with Human Assistance

Yeshasvi Tirupachuri, Gabriele Nava, Lorenzo Rapetti, Claudia Latella, Daniele Pucci
2019 Zenodo  
Physical interactions are inevitable part of human- robot collaboration tasks and rather than exhibiting simple reactive behaviors to human interactions, collaborative robots need to be endowed with intuitive behaviors. This paper proposes a trajectory advancement approach that facilitates advancement along a reference trajectory by leveraging assistance from helpful interaction wrench present during human-robot collaboration. We validate our approach through experiments in simulation with iCub.
doi:10.5281/zenodo.4811871 fatcat:44pbqfar4jahdeioegpaapcil4

A Data Driven Vector Field Oscillator with Arbitrary Limit Cycle Shape [article]

Venus Pasandi, Aiko Dinale, Mehdi Keshmiri, Daniele Pucci
2019 arXiv   pre-print
Cyclic motions in vertebrates, including heart beating, breathing and walking, are derived by a network of biological oscillators having fascinating features such as entrainment, environment adaptation, and robustness. These features encouraged engineers to use oscillators for generating cyclic motions. To this end, it is crucial to have oscillators capable of characterizing any periodic signal via a stable limit cycle. In this paper, we propose a 2-dimensional oscillator whose limit cycle can
more » ... e matched to any periodic signal depicting a non-self-intersecting curve in the state space. In particular, the proposed oscillator is designed as an autonomous vector field directed toward the desired limit cycle. To this purpose, the desired reference signal is parameterized with respect to a state-dependent phase variable, then the oscillator's states track the parameterized signal. We also present a state transformation technique to bound the oscillator's output and its first time derivative. The soundness of the proposed oscillator has been verified by carrying out a few simulations.
arXiv:1910.04706v1 fatcat:xqrdqdxoordefi4fzsxzumbrxm

Whole-Body Geometric Retargeting for Humanoid Robots [article]

Kourosh Darvish, Yeshasvi Tirupachuri, Giulio Romualdi, Lorenzo Rapetti, Diego Ferigo, Francisco Javier Andrade Chavez, Daniele Pucci
2019 arXiv   pre-print
Humanoid robot teleoperation allows humans to integrate their cognitive capabilities with the apparatus to perform tasks that need high strength, manoeuvrability and dexterity. This paper presents a framework for teleoperation of humanoid robots using a novel approach for motion retargeting through inverse kinematics over the robot model. The proposed method enhances scalability for retargeting, i.e., it allows teleoperating different robots by different human users with minimal changes to the
more » ... roposed system. Our framework enables an intuitive and natural interaction between the human operator and the humanoid robot at the configuration space level. We validate our approach by demonstrating whole-body retargeting with multiple robot models. Furthermore, we present experimental validation through teleoperation experiments using two state-of-the-art whole-body controllers for humanoid robots.
arXiv:1909.10080v1 fatcat:3mnuh5xgh5gaxc4pycwipgrb2e
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