Manipulator Performance Criteria Based on Kinematic, Dynamic, and Compliance Models

1999 ◽  
Author(s):  
Mitch Pryor ◽  
Matthew Van Doren ◽  
Delbert Tesar
Keyword(s):  
Design Optimization ◽  
Trajectory Optimization ◽  
Optimal Configuration ◽  
Performance Criteria ◽  
Control Algorithms ◽  
Redundant Manipulators ◽  
Computationally Efficient ◽  
Computer Performance ◽  
Optimal Configurations ◽  
New Criteria

Abstract Currently, few criteria are available that identify a redundant robot’s ‘optimal’ configuration. Criteria developers have been compelled to design computationally efficient metrics in order to maintain necessary control cycle rates this requirement is diminishing in importance with increasing computer performance, allowing designers to implement more complex and effective criteria into the manipulator’s control algorithms. This paper presents a wide variety of criteria that will aid in pinpointing optimal configurations in redundant manipulators. In developing these criteria, the counterproductive (but often necessary) requirement of minimizing the computation rate per criterion is largely ignored. These new criteria are intended for two purposes: (1) the trajectory optimization of redundant manipulators and (2) design optimization for configuring link and joint modules in any manipulator. The criteria presented are derived from the geometric (both 1st and 2nd order), dynamic, and compliance models of a manipulator. All criteria are simulated on a 7DOF serial manipulator, and several results are presented here.

Fractional Order Dynamics in the Trajectory Planning of Redundant and Hyper-Redundant Manipulators

2003 ◽  
Author(s):  
Fernando B. M. Duarte ◽  
J. A. Tenreiro Machado
Keyword(s):  
Fractional Calculus ◽  
Fractional Order ◽  
Trajectory Planning ◽  
Free Space ◽  
Trajectory Optimization ◽  
Generalized Inverse ◽  
Resolution Of Singularities ◽  
Control Algorithms ◽  
Redundant Manipulators ◽  
Kinematic Control

Redundant manipulators have some advantages when compared with classical arms because they allow the trajectory optimization, both on the free space and on the presence of obstacles, and the resolution of singularities. For this type of arms the proposed kinematic control algorithms adopt generalized inverse matrices but, in general, the corresponding trajectory planning schemes show important limitations. Motivated by these problems this paper studies the pseudoinverse-based trajectory planning algorithms, using the theory of fractional calculus.

Geometric, Spatial Path Tracking Using Non-Redundant Manipulators via Speed-Ratio Control

2010 ◽  
Author(s):  
Satyajit Ambike ◽  
James P. Schmiedeler ◽  
Michael M. Stanisˇic´
Keyword(s):  
Path Tracking ◽  
Speed Ratio ◽  
Redundant Manipulators ◽  
Computationally Efficient ◽  
Third Order ◽  
Practical Advantage ◽  
First Order ◽  
Canonical Frame ◽  
Special Cases ◽  
Six Degree Of Freedom

Path tracking can be accomplished by separating the control of the desired trajectory geometry and the control of the path variable. Existing methods accomplish tracking of up to third-order geometric properties of planar paths and up to second-order properties of spatial paths using non-redundant manipulators, but only in special cases. This paper presents a novel methodology that enables the geometric tracking of a desired planar or spatial path to any order with any non-redundant regional manipulator. The governing first-order coordination equation for a spatial path-tracking problem is developed, the repeated differentiation of which generates the coordination equation of the desired order. In contrast to previous work, the equations are developed in a fixed global frame rather than a configuration-dependent canonical frame, providing a significant practical advantage. The equations are shown to be linear, and therefore, computationally efficient. As an example, the results are applied to a spatial 3-revolute mechanism that tracks a spatial path. Spatial, rigid-body guidance is achieved by applying the technique to three points on the end-effector of a six degree-of-freedom robot. A spatial 6-revolute robot is used as an illustration.

Efficient Robust Design Optimization of a Stacker–Reclaimer Structure Under Uncertainty

2019 ◽  
Vol 26 (02) ◽  
pp. 1950009
Author(s):  
Soumya Bhattacharjya ◽  
Mithun Sarkar ◽  
Gaurav Datta ◽  
Saibal Kumar Ghosh
Keyword(s):  
Design Optimization ◽  
Robust Design ◽  
Least Squares Method ◽  
Bulk Material ◽  
Robust Design Optimization ◽  
Computational Time ◽  
Computationally Efficient ◽  
Massive Structure ◽  
Accurate Design ◽  
Design Solutions

A stacker–reclaimer structure (SRS) is a massive structure used for bulk material exploration. Performance of SRS is sensitive to the effect of uncertainty which may lead to catastrophic failure consequences. Thus, in this paper a comparatively new robust design optimization (RDO) approach for design of SRS is explored. The involved parameter of SRS e.g., material loading, incrustation, normal digging, etc., may not have well-defined probability density functions and can be expressed as uncertain but bounded (UBB) type parameters. Hence, RDO is explored for probabilistic as well as UBB cases. Solution of such RDO problem in full simulation approach would require extensive computational time. Hence, response surface method (RSM) based metamodeling approach has been adopted here to alleviate computational burden. Also, as conventional least squares method (LSM) based RSM may be a source of error, this study adopts a comparatively new moving LSM (MLSM) based adaptive RSM in RDO. The RDO results depict that UBB type uncertainty is more critical than the probabilistic case. The proposed MLSM based RDO approach yields reasonably accurate design solutions in a computationally efficient way. The proposed MLSM based RDO approach yields design solutions which ensures safe performance of SRS even in the presence of uncertainty.

Comparison of Damped Velocity and Acceleration Control for Non-Redundant Manipulators

2000 ◽  
Author(s):  
Yu-Che Chen ◽  
Kevin A. O’Neil
Keyword(s):  
Path Tracking ◽  
Least Square ◽  
Dynamics Simulation ◽  
Control Algorithms ◽  
Redundant Manipulators ◽  
Velocity Control ◽  
Redundant Manipulator ◽  
Singular Configurations ◽  
On Line ◽  
Simulation Results

Abstract Damped Least Square (DLS) method has been widely used as an on-line algorithm for manipulator path tracking near and at singular configurations. Wampler (1986) formulated the framework of DLS method applied to velocity control and addressed the applicability of DLS method to acceleration control. The purpose of this paper is to demonstrate the differences in the joint paths generated by damped velocity and damped acceleration control algorithms in non-redundant manipulators. We examine these joint paths, find the cause of the differences, and demonstrate the features of damped acceleration control in non-redundant manipulator dynamics. Simulation results on a planar 2R and a spatial 6R manipulator moving through and near singular configurations verify the phenomena analyzed.

Optimal Design of Hybrid Electric Fuel Cell Vehicles Under Uncertainty and Enterprise Considerations

2008 ◽  
Author(s):  
Jeongwoo Han ◽  
Panos Papalambros
Keyword(s):  
Fuel Cell ◽  
Design Optimization ◽  
Consumer Preferences ◽  
New Technology ◽  
Fuel Cell Vehicles ◽  
Optimization Strategy ◽  
Computationally Efficient ◽  
Fuel Price ◽  
Efficient Manner ◽  
Hybrid Electric

System research on Hybrid Electric Fuel Cell Vehicles (HEFCV) explores the tradeoffs among safety, fuel economy, acceleration, and other vehicle attributes. In addition to engineering considerations, inclusion of business aspects is important in a preliminary vehicle design optimization study. For a new technology, such as fuel cells, it is also important to include uncertainties stemming from manufacturing variability to market response to fuel price fluctuations. This paper applies a decomposition-based multidisciplinary design optimization strategy to an HEFCV. Uncertainty propagated throughout the system is accounted for in a computationally efficient manner. The latter is achieved with a new coordination strategy based on sequential linearizations. The hierarchically partitioned HEFCV design model includes enterprise, powertrain, fuel cell, and battery subsystem models. In addition to engineering uncertainties, the model takes into account uncertain behavior by consumers, and the expected maximum profit is calculated using probabilistic consumer preferences while satisfying engineering feasibility constraints.

Design Optimization of Compound Cylinders Subjected to Autofrettage and Shrink-Fitting Processes

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Ossama R. Abdelsalam ◽  
Ramin Sedaghati
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Finite Element Model ◽  
Design Optimization ◽  
Element Model ◽  
Pressure Vessels ◽  
Stress Profile ◽  
Shrink Fitting ◽  
Shrink Fit ◽  
Optimal Configurations

The autofrettage and shrink-fit processes are used to increase the load bearing capacity and fatigue life of the pressure vessels under thermomechanical loads. In this paper, a design optimization methodology has been proposed to identify optimal configurations of a two-layer cylinder subjected to different combinations of shrink-fit and autofrettage processes. The objective is to find the optimal thickness of each layer, autofrettage pressure and radial interference for each shrink-fit, and autofrettage combination in order to increase the fatigue life of the compound cylinder by maximizing the beneficial and minimizing the detrimental residual stresses induced by these processes. A finite element model has been developed in ansys environment to accurately evaluate the tangential stress profile through the thickness of the cylinder. The finite element model is then utilized in combination with design of experiment (DOE) and the response surface method (RSM) to develop a smooth response function which can be effectively used in the design optimization formulation. Finally, genetic algorithm (GA) combined with sequential quadratic programming (SQP) has been used to find global optimum configuration for each combination of autofrettage and shrink-fit processes. The residual stress distributions and the mechanical fatigue life based on the ASME code for high pressure vessels have been calculated for the optimal configurations and then compared. It is found that the combination of shrink-fitting of two base layers then performing double autofrettage (exterior autofrettage prior to interior autofrettage) on the whole assembly can provide higher fatigue life time for both inner and outer layers of the cylinder.

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