Optimal Load Distribution for Two Industrial Robots Handling a Single Object

1989 ◽  
Vol 111 (2) ◽  
pp. 232-237 ◽  
Author(s):  
Y. F. Zheng ◽  
J. Y. S. Luh
Keyword(s):  
Real Time ◽  
Load Distribution ◽  
Degrees Of Freedom ◽  
Optimization Criterion ◽  
Industrial Robots ◽  
Computational Time ◽  
Optimal Algorithms ◽  
Single Object ◽  
Joint Torques ◽  
Real Time Applications

The load distribution problem for two coordinating industrial robots handling a single object is studied in this paper. When two industrial robots grasp a single object, the total number of applied torques is usually greater than six. Thus the joint torques of two robots for a required motion of the object is not unique. The redundant degrees of freedom may be used to optimize certain kind of performance. We first select the least energy consumption as the optimization criterion. Optimal algorithms without and with a bound on the joint torques are investigated. The results show that the algorithms are computationally complicated which are not suitable for real-time applications. Alternatively, optimal algorithms are then proposed for load distribution with minimum exerted forces on the object. The algorithms are obtained with much less computational time, which makes it attractive for real-time applications. The algorithms are applied to two PUMA 560 type robots as an illustration.

scholarly journals Finite-Horizon Kinetic Energy Optimization of a Redundant Space Manipulator

2021 ◽  
Vol 11 (5) ◽  
pp. 2346
Author(s):  
Alessandro Tringali ◽  
Silvio Cocuzza
Keyword(s):  
Kinetic Energy ◽  
Real Time ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Computational Time ◽  
Redundant Manipulators ◽  
Space Robotics ◽  
Optimal Method ◽  
End Effector ◽  
Global Optimal

The minimization of energy consumption is of the utmost importance in space robotics. For redundant manipulators tracking a desired end-effector trajectory, most of the proposed solutions are based on locally optimal inverse kinematics methods. On the one hand, these methods are suitable for real-time implementation; nevertheless, on the other hand, they often provide solutions quite far from the globally optimal one and, moreover, are prone to singularities. In this paper, a novel inverse kinematics method for redundant manipulators is presented, which overcomes the above mentioned issues and is suitable for real-time implementation. The proposed method is based on the optimization of the kinetic energy integral on a limited subset of future end-effector path points, making the manipulator joints to move in the direction of minimum kinetic energy. The proposed method is tested by simulation of a three degrees of freedom (DOF) planar manipulator in a number of test cases, and its performance is compared to the classical pseudoinverse solution and to a global optimal method. The proposed method outperforms the pseudoinverse-based one and proves to be able to avoid singularities. Furthermore, it provides a solution very close to the global optimal one with a much lower computational time, which is compatible for real-time implementation.

scholarly journals A host–parasite structural analysis of industrial robots

2020 ◽  
Vol 17 (5) ◽  
pp. 172988142095404
Author(s):  
Wei Wei ◽  
Ganwei Cai ◽  
Junjie Gong ◽  
Caixia Ban
Keyword(s):  
Degrees Of Freedom ◽  
Optimization Method ◽  
Industrial Robots ◽  
Joint Torques ◽  
Maximum Deformation ◽  
Overall Performance ◽  
Representation Method ◽  
Branched Chains ◽  
Host Parasite ◽  
Positive Factor

Most driving torques in serial industrial robots are used to overcome the weight of the robot. Although actuators account for a large proportion of the total mass of a robot, they have yet to become a positive factor that enables the robot to achieve gravity balance. This study presents a host–parasite structure to reconstruct the distribution of actuators and achieve gravity balance in robots. First, based on the characteristics of tree–rattan mechanisms, a method for calculating the degrees of freedom and a symbolic representation method for the distribution of branched chains are formulated for host–parasite mechanisms. Second, a configuration analysis and optimization method for host–parasite structure-based robots and a robot prototype are presented. Finally, four host–parasite mechanisms/robots (A, B, C, and D) are compared. The results are as follows. If more parasitic branched chains are added to the yz plane, the loads along axes 2 and 3 become more balanced, which significantly increases the stiffnesses of the mechanism in the y- and z-directions ( Ky and Kz, respectively). If the additional branched chains are closer to the site of maximum deformation, the stiffness of the mechanism in the z-direction ( Kz) increases more significantly. Of the four mechanisms, mechanism D has the best overall performance. The joint torques of mechanism D along axes 2 and 3 are lower than those of mechanism A by 99.78% and 99.18%, respectively. In addition, Kx, Ky, and Kz of mechanism D are 100.56%, 336.19%, and 385.02% of those of mechanism A, respectively. Moreover, the first-order natural frequency of mechanism D is 135.94% of that of mechanism A. Host–parasitic structure is conducive to improving the performance of industrial robots.

scholarly journals Design Combinational Circuit of Reversible Circuits in Emerging Technologies for HCI

2019 ◽  
Vol 8 (4) ◽  
pp. 8570-8573
Keyword(s):  
Real Time ◽  
Control Strategies ◽  
Design Feature ◽  
Mental States ◽  
Computational Time ◽  
Classification Algorithms ◽  
Main Concern ◽  
Combinational Circuit ◽  
Thought Control ◽  
Real Time Applications

The first aim of the thesis is to design feature selection and classification algorithms to distinguish between binary and multiple mental states. These algorithms must produce an optimal performance in terms of accuracy and computational time so that it can be used in real-time applications. Secondly, to design BCI control strategies using reversible combinational ckt like multiplexer, multiplier, adder/sub-tractor for real-time thought control of a human computer interaction (HCI). Reversible logic has emerged as one of the most important approaches and more prominent technology nowadays. Power is the main concern for development and growth of modern VLSI designs.

scholarly journals Real-Time Laser Tracker Compensation of Robotic Drilling and Machining

2020 ◽  
Vol 4 (3) ◽  
pp. 79 ◽  
Author(s):  
Zheng Wang ◽  
Runan Zhang ◽  
Patrick Keogh
Keyword(s):  
Real Time ◽  
Degrees Of Freedom ◽  
Low Cost ◽  
Industrial Robots ◽  
Laser Tracker ◽  
Positional Accuracy ◽  
Working Volume ◽  
Machining Test ◽  
Critical Components ◽  
Aluminum Part

Due to their flexibility, low cost and large working volume, 6-axis articulated industrial robots are increasingly being used for drilling, trimming and machining operations, especially in aerospace manufacturing. However, producing high quality components has demonstrated to be difficult, as a result of the inherent problems of robots, including low structural stiffness and low positional accuracy. These limit robotic machining to non-critical components and parts with low accuracy and surface finish requirements. Studies have been carried out to improve robotic machine capability, specifically positioning accuracy and vibration reduction. This study includes the description of the hardware, software and methodologies developed to compensate robot path errors in real time using a single three-degrees-of-freedom (DOF) laser tracker, as well as the experimental results with and without compensation. Performance tests conducted include ballbar dynamic path accuracy test, a series of drilling case studies and a machining test. The results demonstrate major improvements in path accuracy, hole position accuracy and hole quality, as well as increases in accuracy of a machined aluminum part.

scholarly journals GMS: Grid-Based Motion Statistics for Fast, Ultra-robust Feature Correspondence

2019 ◽  
Vol 128 (6) ◽  
pp. 1580-1593 ◽  
Author(s):  
Jia-Wang Bian ◽  
Wen-Yan Lin ◽  
Yun Liu ◽  
Le Zhang ◽  
Sai-Kit Yeung ◽  
...  
Keyword(s):  
Real Time ◽  
High Speed ◽  
Feature Matching ◽  
Computational Time ◽  
Feature Correspondence ◽  
Fast Calculation ◽  
Geometry Estimation ◽  
Overall Performance ◽  
Real Time Applications ◽  
Grid Based

AbstractFeature matching aims at generating correspondences across images, which is widely used in many computer vision tasks. Although considerable progress has been made on feature descriptors and fast matching for initial correspondence hypotheses, selecting good ones from them is still challenging and critical to the overall performance. More importantly, existing methods often take a long computational time, limiting their use in real-time applications. This paper attempts to separate true correspondences from false ones at high speed. We term the proposed method (GMS) grid-based motion Statistics, which incorporates the smoothness constraint into a statistic framework for separation and uses a grid-based implementation for fast calculation. GMS is robust to various challenging image changes, involving in viewpoint, scale, and rotation. It is also fast, e.g., take only 1 or 2 ms in a single CPU thread, even when 50K correspondences are processed. This has important implications for real-time applications. What’s more, we show that incorporating GMS into the classic feature matching and epipolar geometry estimation pipeline can significantly boost the overall performance. Finally, we integrate GMS into the well-known ORB-SLAM system for monocular initialization, resulting in a significant improvement.

Maintaining Consistency Over A Network in Real-Time Applications

1989 ◽  
Author(s):  
Insup Lee ◽  
Susan Davidson ◽  
Victor Wolfe
Keyword(s):  
Real Time ◽  
Real Time Applications
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