Kinematics of a Novel Single-Loop Under-Actuated Wrist

2012 ◽  
Author(s):  
Raffaele Di Gregorio
Keyword(s):  
Path Planning ◽  
Closed Form ◽  
Nonholonomic Constraint ◽  
Three Dimensional ◽  
Single Loop ◽  
Closed Form Solutions ◽  
Position Analysis ◽  
Tracking Tasks ◽  
Planning Algorithm ◽  
Path Planning Algorithm

A novel type of parallel wrist (PW) is proposed which, differently from previously presented PWs, features a single-loop architecture and only one nonholonomic constraint. Due to the presence of a nonholonomic constraint, the proposed PW type is under-actuated, that is, it is able to control the platform orientation in a three-dimensional workspace by employing only two actuated pairs, one prismatic (P) and the other revolute (R); and it cannot perform tracking tasks. Position analysis and path planning of this novel PW are studied. In particular, all the relevant position analysis problems are solved in closed form, and, based on these closed-form solutions, a path-planning algorithm is built.

On the S-(nS)PU-SPU and S-(nS)PU-2SPU Under-Actuated Wrists

2011 ◽  
Author(s):  
Raffaele Di Gregorio
Keyword(s):  
Path Planning ◽  
Closed Form ◽  
Position Analysis ◽  
Planning Algorithm ◽  
Path Planning Algorithm

In a previous work, this author showed that ten topologies for under-actuated parallel wrists can be generated from the fully-parallel wrist. Three of them are obtained by simply replacing a spherical pair (S) with a nonholonomic spherical pair (nS). The S-(nS)PU-SPU, and S-(nS)PU-2SPU wrists are two of these three. The position analysis of these two wrists is studied in this paper. In particular, all the four position-analysis problems, which are necessary for implementing their path planning, are addressed and solved in closed-form. Despite their different topology, the position-analysis of these two wrists can be practically solved by using the same formulas and algorithms. Based on the deduced formulas, a path-planning algorithm is proposed. The obtained results make the studied wrist topologies able to replace “ordinary” wrists in the manipulation tasks which do not require tracking.

Position Analysis and Path Planning of the S-(nS)PU-SPU and S-(nS)PU-2SPU Underactuated Wrists

2012 ◽  
Vol 4 (2) ◽  
Author(s):  
Raffaele Di Gregorio
Keyword(s):  
Path Planning ◽  
Closed Form ◽  
Position Analysis ◽  
Planning Algorithm ◽  
Path Planning Algorithm

In a previous work, this author showed that ten topologies for underactuated parallel wrists can be generated from a fully parallel wrist (FPW). Three of them are obtained by simply replacing a spherical pair (S) with a nonholonomic spherical pair (nS). The S-(nS)PU-SPU and S-(nS)PU-2SPU wrists are two among these three. The position analysis of these two wrists is studied here. In particular, all the four position-analysis problems, which are necessary for implementing their path planning, are addressed and solved in closed form. Despite their different topology, the position analysis of these two wrists can be practically solved by using the same formulas and algorithms. Based on the deduced formulas, a path-planning algorithm is proposed. The obtained results make the studied wrist topologies able to replace “ordinary” wrists in the manipulation tasks which do not require tracking.

Singularity Analysis of a Single-Loop Underactuated Wrist

2013 ◽  
Author(s):  
Raffaele Di Gregorio
Keyword(s):  
Path Planning ◽  
Closed Form ◽  
Nonholonomic Constraint ◽  
Singularity Analysis ◽  
The Novel ◽  
Single Loop ◽  
Position Analysis ◽  
Singular Configurations ◽  
Geometric Conditions

In a previous paper, this author proposed a novel type of underactuated parallel wrist (PW) with a single-loop architecture containing only one nonholonomic constraint. Moreover, he addressed its position analysis and path planning and showed that closed-form formulas can be used to solve all the finite-kinematics problems involved in the path planning of the novel PW. Here, the instantaneous kinematics and the singularity analysis of this PW are addressed. In particular, both the analytic and geometric conditions which identify the singular configurations are presented together with their static interpretation. The presented results are relevant for designing this type of PWs.

scholarly journals A minimum-time obstacle-avoidance path planning algorithm for unmanned aerial vehicles

2021 ◽  
Author(s):  
Arturo De Marinis ◽  
Felice Iavernaro ◽  
Francesca Mazzia
Keyword(s):  
Path Planning ◽  
Minimum Principle ◽  
Three Dimensional ◽  
Planning Problem ◽  
Pontryagin Minimum Principle ◽  
New Strategy ◽  
Planning Algorithm ◽  
Aerial Vehicle ◽  
Vehicle Trajectory ◽  
Path Planning Algorithm

AbstractIn this article, we present a new strategy to determine an unmanned aerial vehicle trajectory that minimizes its flight time in presence of avoidance areas and obstacles. The method combines classical results from optimal control theory, i.e. the Euler-Lagrange Theorem and the Pontryagin Minimum Principle, with a continuation technique that dynamically adapts the solution curve to the presence of obstacles. We initially consider the two-dimensional path planning problem and then move to the three-dimensional one, and include numerical illustrations for both cases to show the efficiency of our approach.

Collision-free motion planning of multiarm robots using evolutionary algorithms

1997 ◽  
Vol 211 (5) ◽  
pp. 373-384 ◽  
Author(s):  
A S Rana ◽  
A M S Zalzala
Keyword(s):  
Path Planning ◽  
Three Dimensional ◽  
Population Based ◽  
Operational Space ◽  
Planning Algorithm ◽  
Planning Technique ◽  
Pass Through ◽  
Population Based Search ◽  
Path Planning Algorithm ◽  
Path Modification

This paper presents an evolutionary algorithm for the collision-free path planning of multiarm robots. A global path planning technique is used where the paths are represented by a string of via-points that the robots have to pass through, connected together by cubic spline polynomials. Since the entire paths of the robots are considered for optimization, the problem of deadlock between the arms and the static obstacles does not occur. Repeated path modification is done through evolutionary techniques to find an optimized path with respect to length and collision among the robots and the obstacles and the robots themselves. The proposed algorithm departs from simple genetic algorithms in that floating point vector strings represent the chromosomes and customized operators are used to improve upon the performance of the search. Moreover, a local search is carried out on each individual in addition to the global population based search. The result is a highly efficient path-planning algorithm that can deal with complex problems easily. Simulation results are presented for collision-free paths planned for two planar arms and then for two 3 degree-of-freedom (DOF) PUMA®-like arms moving in three-dimensional operational space.

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