scholarly journals Service Arms with Unconventional Robotic Parameters for Intricate Workstations: Optimal Number and Dimensional Synthesis

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Satwinder Singh ◽  
Ekta Singla
Keyword(s):  
Degrees Of Freedom ◽  
Solution Space ◽  
Bilevel Optimization ◽  
Optimal Number ◽  
Dimensional Synthesis ◽  
Cluttered Environments ◽  
Link Service ◽  
Upper Level ◽  
Feasible Solutions ◽  
Task Oriented

A task-oriented design strategy is presented in this paper for service manipulators. The tasks are normally defined in the form of working locations where the end-effector can work while avoiding the obstacles. To acquire feasible solutions in cluttered environments, the robotic parameters (D-H parameters) are allowed to take unconventional values. This enhances the solution space and it is observed that, by inducing this flexibility, the required number of degrees of freedom for fulfilling a given task can be reduced. A bilevel optimization problem is formulated with the outer layer utilizing the binary search method for minimizing the number of degrees of freedom. To enlarge the applicability domain of the proposed strategy, the upper limit of the number of joints is kept more than six. These allowable redundant joints would help in providing solution for intricate workcells. For each iteration of the upper level, a constrained nonlinear problem is solved for dimensional synthesis of the manipulator. The methodology is demonstrated through a case study of a realistic environment of a cluttered server room. A7-link service arm, synthesized using the proposed method, is able to fulfill two different tasks effectively.

Modular Manipulators for Cluttered Environments: A Task-Based Configuration Design Approach

2018 ◽  
Vol 10 (5) ◽  
Author(s):  
Satwinder Singh ◽  
Ashish Singla ◽  
Ekta Singla
Keyword(s):  
Degrees Of Freedom ◽  
Solution Space ◽  
Design Strategy ◽  
Optimal Number ◽  
Design Parameters ◽  
Modular Architecture ◽  
Cluttered Environments ◽  
Three Phase ◽  
Configuration Synthesis ◽  
Torque Values

Modular manipulators gained popularity for their implicit feature of “reconfigurability”—that is, the ability to serve multiple applications by adopting different configurations. As reported in the literature, most of the robotic arms with modular architecture used specific values of twist angles, e.g., 0 deg or 90 deg. Further, the number of degrees-of-freedom (DoF) is also kept fixed. These constraints on the design parameters lead to a smaller solution space for the configuration synthesis problems and may result as no-feasible solution in a cluttered work-cell. To work in a realistic environment, the task-based customized design of a manipulator may need a larger solution space. This work deals with the extension of the modular architecture from conventional values to unconventional values of design parameters, keeping the degrees-of-freedom also as variable. This results into an effective utilization of modular designs for highly cluttered environments. A three-phase design strategy is proposed in the current work. The design strategy starts with the decision of optimal number of modules required for the given environment in the first phase, which is followed by task-based “configuration planning” and “optimal assembly” in the second and third phase, respectively. Three types of modules are proposed with same architecture and different sizes—heavy (H), medium (M), and light (L). The configuration planning includes detailed discussion on the type-selection of the modules and their possible combinations. Comparison of all possible n-link combinations is analyzed based upon the optimized results with respect to the minimum torque values. Case studies of a power plant with two different workspaces are included to illustrate the three-phase strategy representing the importance of modularity in nonrepetitive maintenance tasks.

Maximizing safety margins in task-based design of redundant manipulators for cluttered environments

2017 ◽  
Vol 231 (3) ◽  
pp. 275-285
Author(s):  
E. Singla ◽  
S. Singh ◽  
B. Dasgupta
Keyword(s):  
Degrees Of Freedom ◽  
Solution Space ◽  
Global Solutions ◽  
Design Stage ◽  
Optimized Design ◽  
Redundant Manipulators ◽  
Large Solution ◽  
Cluttered Environments ◽  
Safety Margins ◽  
Architectural Planning

Kinematically redundant manipulators help in handling environmental constraints with extra degrees of freedom, but a large number of links may also lead to significant cumulative errors at the distal end, increasing the likelihood of collisions. The focus of this paper is to synthesize a robot with maximized tolerance to avoid potential collisions, while maneuvering in the workspace. A maximized-tolerance-based method in the design stage provides a significant margin to be utilized further during architectural planning and/or in error compensation against any joint clearance error. This is the main contribution of this paper. The strategy is applicable with even a large number of degrees of freedom. A measure, named as RoboGin, is defined both for a single configuration and for a set of configurations. Maximizing this metric over the large solution space of all robotic parameters provides an optimized design from the reliability perspective. The other requirements related to robot’s reachability at the specified task space locations (TSLs), kinematic conditioning and path connectivity are framed as constraints in the formulated optimization problem. The global solutions computed through a simulated annealing technique show significant improvements in overall safety margins even in highly cluttered environments and with a large number of links. Implementation of the proposed strategy is demonstrated through realistic cluttered environments of a power plant, for a leakage testing application.

scholarly journals Hybrid Seven-bar Press Mechanism

2018 ◽  
Vol 12 (3) ◽  
pp. 181-187
Author(s):  
M. Erkan Kütük ◽  
L. Canan Dülger
Keyword(s):  
Genetic Algorithm ◽  
Objective Function ◽  
Design Optimization ◽  
Hybrid System ◽  
Degrees Of Freedom ◽  
Dimensional Synthesis ◽  
Design Variables ◽  
Optimization Study ◽  
Metal Stamping

An optimization study with kinetostatic analysis is performed on hybrid seven-bar press mechanism. This study is based on previous studies performed on planar hybrid seven-bar linkage. Dimensional synthesis is performed, and optimum link lengths for the mechanism are found. Optimization study is performed by using genetic algorithm (GA). Genetic Algorithm Toolbox is used with Optimization Toolbox in MATLAB®. The design variables and the constraints are used during design optimization. The objective function is determined and eight precision points are used. A seven-bar linkage system with two degrees of freedom is chosen as an example. Metal stamping operation with a dwell is taken as the case study. Having completed optimization, the kinetostatic analysis is performed. All forces on the links and the crank torques are calculated on the hybrid system with the optimized link lengths

Workspace, dexterity and dimensional optimization of microhexapod

2015 ◽  
Vol 35 (4) ◽  
pp. 341-347 ◽  
Author(s):  
E. Rouhani ◽  
M. J. Nategh
Keyword(s):  
Degrees Of Freedom ◽  
Optimization Problem ◽  
Screw Theory ◽  
Design Parameters ◽  
Dimensional Synthesis ◽  
Content Type ◽  
Workspace Analysis ◽  
The Difference ◽  
Flexure Joints ◽  
6 Degrees Of Freedom

Purpose – The purpose of this paper is to study the workspace and dexterity of a microhexapod which is a 6-degrees of freedom (DOF) parallel compliant manipulator, and also to investigate its dimensional synthesis to maximize the workspace and the global dexterity index at the same time. Microassembly is so essential in the current industry for manufacturing complicated structures. Most of the micromanipulators suffer from their restricted workspace because of using flexure joints compared to the conventional ones. In addition, the controllability of micromanipulators inside the whole workspace is very vital. Thus, it is very important to select the design parameters in a way that not only maximize the workspace but also its global dexterity index. Design/methodology/approach – Microassembly is so essential in the current industry for manufacturing complicated structures. Most of the micromanipulators suffer from their restricted workspace because of using flexure joints compared to the conventional ones. In addition, the controllability of micromanipulators inside the whole workspace is very vital. Thus, it is very important to select the design parameters in a way that not only maximize the workspace but also its global dexterity index. Findings – It has been shown that the proposed procedure for the workspace calculation can considerably speed the required calculations. The optimization results show that a converged-diverged configuration of pods and an increase in the difference between the moving and the stationary platforms’ radii cause the global dexterity index to increase and the workspace to decrease. Originality/value – The proposed algorithm for the workspace analysis is very important, especially when it is an objective function of an optimization problem based on the search method. In addition, using screw theory can simply construct the homogeneous Jacobian matrix. The proposed methodology can be used for any other micromanipulator.

Optimization in Trajectory Planning of Multi-Jointed Fingers in Dextrous Hand Designs

1991 ◽  
Author(s):  
A. Meghdari ◽  
H. Sayyaadi
Keyword(s):  
Dynamic Programming ◽  
Motion Control ◽  
Trajectory Planning ◽  
Degrees Of Freedom ◽  
Optimization Technique ◽  
Dynamic Programming Algorithm ◽  
Programming Algorithm ◽  
Kinematics And Dynamics ◽  
Feasible Solutions ◽  
Dextrous Hand

Abstract An optimization technique based on the well known Dynamic Programming Algorithm is applied to the motion control trajectories and path planning of multi-jointed fingers in dextrous hand designs. A three fingered hand with each finger containing four degrees of freedom is considered for analysis. After generating the kinematics and dynamics equations of such a hand, optimum values of the joints torques and velocities are computed such that the finger-tips of the hand are moved through their prescribed trajectories with the least time or/and energy to reach the object being grasped. Finally, optimal as well as feasible solutions for the multi-jointed fingers are identified and the results are presented.

Reduction of the Dimension of the Upper Level Problem in a Bilevel Optimization Model

2015 ◽  
pp. 289-308
Author(s):  
Stephan Dempe ◽  
Vyacheslav Kalashnikov ◽  
Gerardo A. Pérez-Valdés ◽  
Nataliya Kalashnykova
Keyword(s):  
Optimization Model ◽  
Bilevel Optimization ◽  
Level Problem ◽  
Upper Level

Identification of Structural Systems With Limited Number of Sensors and Actuators

2004 ◽  
Author(s):  
Jun Yu ◽  
Maura Imbimbo ◽  
Raimondo Betti
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Models ◽  
Solution Space ◽  
Order Model ◽  
Sensors And Actuators ◽  
Common Assumption ◽  
Reduced Order ◽  
Different Types ◽  
The Common ◽  
Inverse Vibration

The common assumption in the so-called linear inverse vibration problem, which provides the mass/stiffness/damping matrices of second order dynamic models, is the availability of a full set of sensors and actuators. In “reduced-order” problems (with limited number of instrumentation), only the components of the eigenvector matrix regarding the measured degrees of freedom can be successfully identified while nothing can be said about the components connected to the unmeasured degrees of freedom. This paper presents a recently developed “reduced-order” model and expands such a model to a “full-order” one that is quite useful in damage detection. The five representative categories of “reduced-order” problems, defined by considering different types of geometrical conditions, are analyzed and a discussion on their solution space has been performed. The effectiveness and robustness of this approach is shown by means of a numerical example.

scholarly journals Design of a Two-DOFs Driving Mechanism for a Motion-Assisted Finger Exoskeleton

2020 ◽  
Vol 10 (7) ◽  
pp. 2619 ◽  
Author(s):  
Giuseppe Carbone ◽  
Eike Christian Gerding ◽  
Burkard Corves ◽  
Daniele Cafolla ◽  
Matteo Russo ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Experimental Tests ◽  
Design Solution ◽  
Driving Mechanism ◽  
Dimensional Synthesis ◽  
Linkage Mechanism ◽  
Healthy Human ◽  
Wide Range ◽  
Finger Motion ◽  
Human Finger

This paper presents a novel exoskeleton mechanism for finger motion assistance. The exoskeleton is designed as a serial 2-degrees-of-freedom wearable mechanism that is able to guide human finger motion. The design process starts by analyzing the motion of healthy human fingers by video motion tracking. The experimental data are used to obtain the kinematics of a human finger. Then, a graphic/geometric synthesis procedure is implemented for achieving the dimensional synthesis of the proposed novel 2 degrees of freedom linkage mechanism for the finger exoskeleton. The proposed linkage mechanism can drive the three finger phalanxes by using two independent actuators that are both installed on the back of the hand palm. A prototype is designed based on the proposed design by using additive manufacturing. Results of numerical simulations and experimental tests are reported and discussed to prove the feasibility and the operational effectiveness of the proposed design solution that can assist a wide range of finger motions with proper adaptability to a variety of human fingers.

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