Design Parameters Of Manipulator Research Articles

Design methodology of functionally graded cellular materials: Manipulating design parameters of triply periodic minimal surfaces through three-dimensional density distributions

Functionally Graded Cellular Materials (FGCM) with variable volume fractions have demonstrated significant advantages, including weight reduction, improved stiffness, and enhanced load distribution, when compared to uniform density counterparts. Their design is often characterized by the application of a density distribution to locally modify Representative Volume Elements (RVEs). Current studies have explored the application of Triply Periodic Minimal Surfaces (TPMS) topologies, given their capability to create seamless and interconnected structures, thus avoiding stress concentration issues commonly encountered in traditional lattice configurations. Consequently, this paper introduces a design methodology tailored to TPMS-based FGCM allowing for independent or simultaneous adjustments of RVE thickness and size. Models for predicting relative density as a function of the RVE design parameters of Primitive and Gyroid topologies are presented and discussed. These models are employed to adapt the topologies to three-dimensional density distributions. The proposed method is implemented as a set of design tools and is illustrated for the studied TPMS topologies.

Task-Specific Manipulator Design and Trajectory Synthesis

This letter addresses the challenge of determining the optimal design of a customizable robot for a given task. We present a motion planner that not only prescribes a path, but also synthesizes the robot design to follow that path. Our approach treats design variables as part of an inverse kinematics problem to jointly optimize manipulator design parameters and trajectory. We apply our method to two distinct problems where rapid prototyping and customization are desirable: an arm prototyped for a future Mars mission, and a wearable backpack-mounted arm. We then propose a novel method to minimize the number of joints in the mechanism while maintaining its ability to reach workspace task poses. We combine these methods into a framework in which we iteratively optimize and simplify task-specialized manipulator designs.

An optimization procedure based on kinematics analysis for the design parameters of a 4-UPU parallel manipulator

The paper presents the kinematics analysis of a 4-UPU fully parallel manipulator and a numerical procedure for its optimization. The 4-UPU kinematics is featured by four UPU legs, moreover the prismatic joint of each leg is supposed to be actuated. The end-effector has 4 degrees of freedom (Dofs), the three translations and the rotation along the direction perpendicular to the base platform. Singularity configurations have been analytically determined and the analysis of both actuation and constraint Jacobian by screw theory has been performed. Finally, a numerical procedure for the optimization of the design parameters of the manipulator is presented. The optimization procedure has been carried out using adimensional parameters in order to generalize the obtained results. The presented optimization procedure allows to define the ratios between the geometrical features of the manipulator which maximize a generic performance parameter in a designed workspace by avoiding all the possible singularity conditions. The obtained results are useful for the design of all the manipulators based on the 4-UPU kinematics. In particular, the case study of the design of a wearable fingertip haptic device is presented and discussed.

A new exergoeconomic optimisation methodology applied to an industrial distillation system

In this work, we simulate and optimise an industrial distillation system to produce bioethanol manipulating design parameters to reduce the total exergy loss inside the columns and taking into account the economic parameters. The operational parameters are validated using Aspen Plus through the analysis of the exergy loss profile. However, the variation of the number of stages is not straightforward in processes simulators because requires to evaluate the optimal position to insert the stage in the column (i. e., stripping or rectification section). It is demonstrated that the number of stages tightly impacts the energy efficiency of the columns. The optimisation is realised in Matlab to relate the total exergy loss inside the columns with its cost identifying the sections with greater exergy loss, inserting new stages (defined by the user) and calculating the capital cost associated. The results show that is possible thermodynamically optimise the industrial distillation system.

Optimal design of manipulator parameter using evolutionary optimization techniques

SUMMARYA robot must have high positioning accuracy and repeatability for precise applications. However, variations in performance are observed due to the effect of uncertainty in design and process parameters. So far, there has been no attempt to optimize the design parameters of manipulator by which performance variations will be minimum. A modification in differential evolution optimization technique is proposed to incorporate the effect of noises in the optimization process and obtain the optimal design of manipulator, which is insensitive to noises. This approach has been illustrated by selecting optimal parameter of 2-DOF RR planar manipulator and 4-DOF SCARA manipulator. The performance of proposed approach has been compared with genetic algorithm with similar modifications. It is observed that the optimal results are obtained with lesser computations in case of differential evolution technique. This approach is a viable alternative for costly prototype testing, where only kinematic and dynamic models of manipulator are dealt with.

Design Strategy of Serial Manipulators With Certified Constraint Satisfaction

This paper presents the design strategy of serial manipulators with constraint satisfaction. The algorithm provides certified solutions to the range of values of the manipulator design parameters that satisfy the given constraints for all points inside a desired workspace. Alternatively, it can also be used to obtain the achievable workspace of a particular manipulator topology within which a set of given constraints are satisfied. This strategy can therefore be applied to the general case of a serial manipulator design problem, robots of adjustable parameters, or even reconfigurable robot strategy to obtain a suitable topology. The interval-based algorithm was implemented on an example serial anthropomorphic manipulator with joint displacement constraints and obtains the possible variations to the manipulator topology that allow the required workspace to be achievable under the given joint displacement constraints. Results are presented and discussed.

Topology optimisation and singularity analysis of a 3-SPS parallel manipulator with a passive constraining spherical joint

This study focuses on topology optimisation and singularity analysis of a 3-SPS parallel manipulator with three identical limbs made of spherical + prismatic + spherical joints, and a passive spherical joint connecting a moving platform to a fixed base. First, the number synthesis for spatial parallel manipulators with three limbs is reviewed and the existence conditions for the parallel manipulator considered in this study are presented. Second, the inverse position formulation is established; a constrained optimisation algorithm based on the condition number of the manipulator Jacobian matrix over the entire workspace of the manipulator is employed to determine design parameters. A set of optimisation trials is accomplished to prove that the algorithm is valid for determining the optimum values of the manipulator design parameters. Third, forward and inverse Jacobian matrices are derived, and then the singularity loci of the manipulator with different values of the design parameters are generated using a methodology not requiring the explicit expressions for the roots of the determinant of the Jacobians. The singularity loci have been presented to show that this methodology is an efficient and versatile technique in the singularity determination of manipulators, and that a well-conditioned workspace has the least number of singular configurations.

Graphical representation of nutrient removal in constructed wetlands

A simple steady state model that is conceptually similar to those of Vollenweider and Dillon was developed to predict phosphorus retention in a wetland treatment system. The proposed model calculates wetland TP outflow concentration (TPout) as a function of TP mass loading rate (L), hydraulic loading rate (qs), and phosphorus settling velocity (νs). A phosphorus-removal diagram was developed, based on this simple model, and plots L, qs, νs against TPout on a three-axis graph. Comparisons between predicted and observed TPout in operating wetlands were in good agreement and indicated that a simple relationship governing phosphorus retention in wetlands exists and this relationship can be used to predict and evaluate wetland treatment performance. The proposed diagram can also be used to answer management questions by manipulating design parameters, such as mass loading and hydraulic loading rate, to evaluate economic impacts due to alternatives such as increasing the size of a wetland surface area, changing water depth, or reducing mass loading rates with pre-treatment options.

Decentralized Adaptive Control of a Directly Driven Hydraulic Manipulator: Part 1: Theory

A new approach to adaptive control of manipulators is presented in this paper. The proposed controller for each individual axis is of the model reference type, designed through the use of variable structure systems theory. A novel feature of the controller is the introduction of a series-parallel model of the model-following error. The use of this model ensures system stability even if the manipulator design parameters or payload bounds are exceeded. Chattering of the system, associated with variable structure systems, is eliminated by arranging for the control objective to be physically achievable.

Computer-aided design of manipulation robots via multi-parameter optimization

In the paper are presented the basic ideas of computer-aided design of manipulation robots based on adopted optimizational criteria and on set constraints of strengths, as well as on actuator capabilities. Using complete models of manipulator dynamics, a simulation programme was derived, giving at its output the optimal design parameters of manipulator. An algorithm was formed, optimizing simultaneously two of the several significant manipulator parameters. In one case these are two diameters of circular cross-section segments, in another, one is a diameter and the other the reducing ratio of the DC motor type actuator.