scholarly journals Robust Object Grasping using Force Compliant Motion Primitives

2012 ◽  
Author(s):  
Moslem Kazemi ◽  
Jean-Sebastien Valois ◽  
J. Andrew Bagnell ◽  
Nancy Pollard
Keyword(s):  
Motion Primitives ◽  
Compliant Motion

scholarly journals Incorporation of Potential Fields and Motion Primitives for the Collision Avoidance of Unmanned Aircraft

2021 ◽  
Vol 11 (7) ◽  
pp. 3103
Author(s):  
Kyuman Lee ◽  
Daegyun Choi ◽  
Donghoon Kim
Keyword(s):  
Collision Avoidance ◽  
Search Algorithm ◽  
Unmanned Aircraft ◽  
Artificial Potential Field ◽  
Tree Search ◽  
Local Minima ◽  
Collision Risk ◽  
Motion Primitives ◽  
Multiple Uavs ◽  
Tree Search Algorithm

Collision avoidance (CA) using the artificial potential field (APF) usually faces several known issues such as local minima and dynamically infeasible problems, so unmanned aerial vehicles’ (UAVs) paths planned based on the APF are safe only in a certain environment. This research proposes a CA approach that combines the APF and motion primitives (MPs) to tackle the known problems associated with the APF. Since MPs solve for a locally optimal trajectory with respect to allocated time, the trajectory obtained by the MPs is verified as dynamically feasible. When a collision checker based on the k-d tree search algorithm detects collision risk on extracted sample points from the planned trajectory, generating re-planned path candidates to avoid obstacles is performed. After rejecting unsafe route candidates, one applies the APF to select the best route among the remaining safe-path candidates. To validate the proposed approach, we simulated two meaningful scenario cases—the presence of static obstacles situation with local minima and dynamic environments with multiple UAVs present. The simulation results show that the proposed approach provides smooth, efficient, and dynamically feasible pathing compared to the APF.

scholarly journals Towards Time-Optimal CACD Motion Primitives with Smooth Transitions

2020 ◽  
Vol 53 (2) ◽  
pp. 15544-15549
Author(s):  
Gregor Klančar ◽  
Martina Loknar ◽  
Sašo Blažič
Keyword(s):  
Motion Primitives ◽  
Time Optimal ◽  
Smooth Transitions

scholarly journals Purcell’s Three-Link Swimmer: Assessment of Geometry and Gaits for Optimal Displacement and Efficiency

Mathematics ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1088
Author(s):  
Cristina Nuevo-Gallardo ◽  
José Emilio Traver ◽  
Inés Tejado ◽  
Blas M. Vinagre
Keyword(s):  
Reynolds Number ◽  
Multiobjective Optimization ◽  
The Other ◽  
Optimal Method ◽  
Optimal Velocity ◽  
Motion Primitives ◽  
Motion Primitive ◽  
Control Objective ◽  
Optimal Efficiency ◽  
The One

This paper studies the displacement and efficiency of a Purcell’s three-link microswimmer in low Reynolds number regime, capable of moving by the implementation of a motion primitive or gait. An optimization is accomplished attending to the geometry of the swimmer and the motion primitives, considering the shape of the gait and its amplitude. The objective is to find the geometry of the swimmer, amplitude and shape of the gaits which make optimal the displacement and efficiency, in both an individual way and combined (the last case will be referred to as multiobjective optimization). Three traditional gaits are compared with two primitives proposed by the authors and other three gaits recently defined in the literature. Results demonstrate that the highest displacement is obtained by the Tam and Hosoi optimal velocity gait, which also achieves the best efficiency in terms of energy consumption. The rectilinear and Tam and Hosoi optimal efficiency gaits are the second optimum primitives. Regarding the multiobjective optimization and considering the two criteria with the same weight, the optimum gaits turn out to be the rectilinear and Tam and Hosoi optimal efficiency gaits. Thus, the conclusions of this study can help designers to select, on the one hand, the best swimmer geometry for a desired motion primitive and, on the other, the optimal method of motion for trajectory tracking for such a kind of Purcell’s swimmers depending on the desired control objective.

Risk assessment in mission planning of uninhabited aerial vehicles

2019 ◽  
Vol 233 (10) ◽  
pp. 3499-3518 ◽  
Author(s):  
Giulio Avanzini ◽  
David S Martínez
Keyword(s):  
Initial Conditions ◽  
Mission Planning ◽  
Unmanned Aerial Systems ◽  
Steady State Condition ◽  
Motion Primitives ◽  
Uninhabited Aerial Vehicles ◽  
Aerial Systems ◽  
The Impact ◽  
Navigation Errors ◽  
Time Of Failure

A procedure for evaluating the risk related to the use of unmanned aerial systems over populated areas is proposed. A nominal trajectory, planned for performing a given mission, is represented by means of motion primitives, that is segments and arcs flown in a steady-state condition. The risk of hitting a person on the ground after catastrophic failure is evaluated as a function of vehicle reliability and population density (assumed known), and position of the impact point (which depends on initial conditions at the time of failure and trajectory flown afterwards). In the deterministic case, a lethal area is introduced and the risk at each point on the ground is proportional to the amount of time spent by the point inside the lethal area. Under the assumptions of a ballistic fall, the position of the lethal area with respect to the nominal trajectory depends only on altitude and velocity at the time of failure. When the effect of navigation errors is introduced, impact points are described by a statistical impact footprint, assuming that position and velocity errors at time of failure are normally distributed with known standard deviations. The two approaches are compared for a fictitious, yet realistic, mission scenario.

Biped walking and stairs climbing using reconfigurable adaptive motion primitives

2016 ◽  
Author(s):  
Mirko Rakovic ◽  
Branislav Borovac ◽  
Jose Santos-Victor ◽  
Aleksandar Batinica ◽  
Milutin Nikolic ◽  
...  
Keyword(s):  
Biped Walking ◽  
Motion Primitives ◽  
Adaptive Motion
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