Reliable redundancy resolution strategies for kinematically redundant parallel manipulators

2022 ◽  
Vol 167 ◽  
pp. 104531
Author(s):  
Hiparco Lins Vieira ◽  
João Vitor de Carvalho Fontes ◽  
Maíra Martins da Silva
Keyword(s):  
Parallel Manipulators ◽  
Redundancy Resolution ◽  
Resolution Strategies

Trajectory Planning and Impact Reduction in Wire-Actuated Parallel Manipulators With Elastic Wires

2010 ◽  
Author(s):  
Maryam Agahi ◽  
Leila Notash
Keyword(s):  
Trajectory Planning ◽  
Parallel Manipulator ◽  
Optimal Trajectory ◽  
Parallel Manipulators ◽  
Mobile Platform ◽  
Kinematics And Dynamics ◽  
Redundancy Resolution ◽  
Impact Reduction ◽  
Optimization Routine ◽  
Optimal Trajectory Planning

In the work presented, the optimal trajectory planning in wire-actuated parallel manipulators in the presence of an obstacle is investigated. The kinematics and dynamics of a wire-actuated parallel manipulator considering the elasticity and damping effects of wires are described. The redundancy resolution of planar wire-actuated parallel manipulators is investigated at the torque level in order to perform desirable tasks to minimize the effect of impact, while maintaining positive tension in each wire. A local optimization routine is used in the simulation to minimize the tension in the wires while modifying the trajectory of the mobile platform and maintaining positive wire tensions. During collision, the tension in the wires is optimized to reduce the effect of impact, and after collision, the trajectory is modified and the wire tensions are minimized in order to avoid collision for the remainder of the trajectory. The effectiveness of the presented approach is studied through a simulation of an example planar wire-actuated manipulator.

Redundancy Resolution of Kinematically Redundant Parallel Manipulators Via Differential Dynamic Programing

2017 ◽  
Vol 9 (4) ◽  
Author(s):  
João Cavacanti Santos ◽  
Maíra Martins da Silva
Keyword(s):  
Parallel Manipulators ◽  
Projection Methods ◽  
Inverse Kinematic ◽  
Gradient Projection ◽  
Redundancy Resolution ◽  
Inverse Kinematic Problem ◽  
Serial Manipulators ◽  
Optimal Inputs ◽  
Dynamic Programing ◽  
Gradient Projection Methods

Kinematic redundancy may be an efficient way to improve the performance of parallel manipulators. Nevertheless, the inverse kinematic problem of this kind of manipulator presents infinite solutions. The selection of a single kinematic configuration among a set of many possible ones is denoted as redundancy resolution. While several redundancy resolution strategies have been proposed for planning the motion of redundant serial manipulators, suitable proposals for parallel manipulators are seldom. Redundancy resolution can be treated as an optimization problem that can be solved locally or globally. Gradient projection methods have been successfully employed to solve it locally. For global strategies, these methods may be computationally demanding and mathematically complex. The main objective of this work is to exploit the use of differential dynamic programing (DDP) for decreasing the computational demand and mathematical complexity of a global optimization based on the gradient projection method for redundancy resolution. The outcome of the proposed method is the optimal inputs for the active joints for a given trajectory of the end-effector considering the input limitations and different cost functions. Using the proposed method, the performance of a redundant 3PRRR manipulator is investigated numerically and experimentally. The results demonstrate the capability and versatility of the strategy.

On redundancy resolution and energy consumption of kinematically redundant planar parallel manipulators

Robotica ◽  
2018 ◽  
Vol 36 (6) ◽  
pp. 809-821 ◽  
Author(s):  
Andrés Gómez Ruiz ◽  
João Cavalcanti Santos ◽  
Jan Croes ◽  
Wim Desmet ◽  
Maíra Martins da Silva
Keyword(s):  
Energy Consumption ◽  
Predictive Control ◽  
Energy Efficient ◽  
Parallel Manipulators ◽  
Inverse Kinematic ◽  
Control Technique ◽  
Redundancy Resolution ◽  
Inverse Kinematic Problem ◽  
Resolution Scheme ◽  
The Impact

SUMMARYNovel kinematic architectures can be alternatives for designing energy efficient robotic systems. In this work, the impact of kinematic redundancies in the energy consumption of a planar PKM, the 3PRRR manipulator, is experimentally verified. Because of the presence of the kinematic redundancies, the inverse kinematic problem presents infinity solutions. In this way, a redundancy resolution scheme based on the Model Predictive Control technique is proposed and exploited. It can be concluded that the energy consumption of the non-redundant parallel manipulator 3RRR for executing predefined tasks can be considerably reduced by the inclusion of kinematic redundancies.

Model-based joint and task space control strategies for a kinematically redundant parallel manipulator

Robotica ◽  
2021 ◽  
pp. 1-17
Author(s):  
João Vitor de Carvalho Fontes ◽  
Fernanda Thaís Colombo ◽  
Natássya Barlate Floro da Silva ◽  
Maíra Martins da Silva
Keyword(s):  
Parallel Manipulator ◽  
Control Strategies ◽  
Parallel Manipulators ◽  
Torque Control ◽  
Redundancy Resolution ◽  
Task Space ◽  
Kinematic Redundancy ◽  
Model Based ◽  
The Impact ◽  
Computed Torque

Abstract One alternative to overcome the presence of singularities within Parallel Manipulators’ workspace is kinematic redundancy. This design alternative can be realized by adding an extra active joint to a kinematic chain. Due to this addition, the IKM presents an infinite number of solutions requiring a redundancy resolution scheme. Moreover, Parallel Manipulators’ control may require complex strategies due to their coupled and complex dynamic and kinematic relations. In this work, a model-free, a joint space computed torque, and a hybrid joint-task-space computed torque control strategies are experimentally compared for a kinematically redundant parallel manipulator. The latter is a novel strategy that requires the measurement of the end-effector’s pose, which is performed by an eye-to-hand limited frame rate camera. The impact of up to three kinematic redundancy levels is also experimentally evaluated using prepositioning and ongoing positioning redundancy resolution schemes. The data are assessed by evaluating a prescribed trajectory executed using a planar kinematically redundant parallel manipulator. These results indicate that kinematic redundancy can not only be used as an alternative design for reducing the presence of singular regions, as claimed in the literature, but also be used along with model-based control strategies for improving dynamic performance and accuracy of parallel manipulators.

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