Minimum Energy Control of Redundant Manipulators With Axes Coupling and Compounded Path

2014 ◽  
Author(s):  
Lior Alpert ◽  
Yoram Halevi
Keyword(s):  
Energy Consumption ◽  
Degrees Of Freedom ◽  
Minimum Energy ◽  
Joint Motion ◽  
Redundant Manipulators ◽  
End Effector ◽  
Minimum Energy Control ◽  
Optimization Simulation ◽  
Simulation Results ◽  
The Individual

In redundant manipulation systems the end-effector path does not completely determine the trajectories of all the individual degrees of freedom and this freedom can be used to enhance the performance in some sense. The paper deals with utilizing the redundancy to minimize energy consumption. It extends previous results by considering more general cases of possible coupling between the axes, e.g. three axes for planar motion, and more general paths comprising of several primitive motions connected dynamically. The solution is based on projections into lower subspaces that separate the system and the input into two parts. One that is completely determined by the end-effector path and the other that is free for optimization. Simulation results show that redundancy, even with limited joint motion, can lead to a considerable reduction in energy consumption.

Minimum Energy Control of Redundant Linear Manipulators

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Yoram Halevi ◽  
Emanuele Carpanzano ◽  
Giuseppe Montalbano
Keyword(s):  
Energy Consumption ◽  
Degrees Of Freedom ◽  
Minimum Energy ◽  
Input Voltage ◽  
Joint Motion ◽  
End Effector ◽  
Minimum Energy Control ◽  
The Individual ◽  
The Cost ◽  
Exact Energy

In redundant manipulation systems, the end-effector path does not completely determine the trajectories of all the individual degrees of freedom (dof) and the additional dofs can be used to enhance the performance in some sense. The paper deals with utilizing the redundancy to minimize energy consumption. A full linear electromechanical model is used, and the exact energy consumption is calculated. The optimization includes also displacement limits via penalty functions that are included in the cost function. The optimal trajectory is feasible in the sense that it can be obtained by a finite input voltage and all the velocities are continuous. The solution is based on projections that separate the system and the input into two parts. One that is completely determined by the end-effector path and the other that is free for optimization. The important and delicate issue of boundary conditions is resolved accordingly. Simulation results show that redundancy, even with limited joint motion, can lead to a considerable reduction in energy consumption.

Minimum Energy Control of Redundant Cartesian Manipulators

2012 ◽  
Author(s):  
Yoram Halevi ◽  
Emanuele Carpanzano ◽  
Giuseppe Montalbano
Keyword(s):  
Degrees Of Freedom ◽  
Minimum Energy ◽  
Joint Motion ◽  
Energy Control ◽  
End Effector ◽  
Considerable Saving ◽  
Minimum Energy Control ◽  
Simulation Results ◽  
The Individual ◽  
The Cost

In redundant manipulation systems the end-effector path does not completely determine the trajectories of all the individual degrees of freedom (dof). The redundancy is used in this paper to minimize energy consumption. A full electromechanical model is used, and the invested energy is calculated explicitly. The optimization includes also displacement limits via penalty functions that are included in the cost function. The solution is based on separating the system and the input into two parts. One that is completely determined by the end-effector path and the other that is driven by it, yet free for optimization. The boundary conditions are resolved in a similar manner, where the physical values are translated to the scaled down system by using a specific projection. Simulation results show that even with limited joint motion, the redundancy can lead to a considerable saving in energy.

Gateway Configuration for Rapid Pick-and-Place Operations of 2-Degrees-of-Freedom Parallel Robots

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Andrea Martin-Parra ◽  
David Rodriguez-Rosa ◽  
Sergio Juarez-Perez ◽  
Guillermo Rubio-Gomez ◽  
Antonio Gonzalez-Rodriguez ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Degrees Of Freedom ◽  
Jacobian Matrix ◽  
Parallel Robots ◽  
End Effector ◽  
Joint Coordinates ◽  
Pick And Place ◽  
Low Energy Consumption ◽  
Simulation Results ◽  
The Difference

Abstract This article presents a new assembling for 2 degrees-of-freedom (DOFs) parallel robots for executing rapid pick-and-place operations with low energy consumption. A conventional design of 2-DOF parallel robots is based on five-bar mechanisms. Collisions between links are highly possible, restricting the end-effector workspace and/or increasing the trajectory time to avoid collisions. In this article, an alternative assembling for preventing collisions is presented. This novel assembling allows exploring the difference between the four five-bar mechanism configurations for the same position of the end-effector. Some of these configurations yield to lower time and/or lower energy consumption for the same motorization. First, a dynamic model of the robot has been developed using matlab® and simulink® and validated by comparison with the results obtained by adams® software. A robust cascade PD regulator for controlling joint coordinates has been tuned providing a high accurate end-effector positioning. Finally, simulation results of four configurations are presented for executing controlled maneuvers. The obtained results demonstrate that the conventional configuration is the worst one in terms of trajectory time or energy consumption and, conversely, the best one corresponds to an uncommonly used configuration. A workspace map where all configurations provide faster maneuvers has been obtained in terms of Jacobian matrix and mechanism elbows distance. The results presented here allow designing a rapid manipulator for pick-and-place operations.

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 self-aligning end-effector robot for individual joint training of the human arm

2021 ◽  
Vol 8 ◽  
pp. 205566832110198
Author(s):  
Sivakumar Balasubramanian ◽  
Sandeep Guguloth ◽  
Javeed Shaikh Mohammed ◽  
S Sujatha
Keyword(s):  
Degrees Of Freedom ◽  
Simple Algorithm ◽  
Optimization Procedure ◽  
Estimation Procedure ◽  
Compact Structure ◽  
End Effector ◽  
Human Arm ◽  
Robotic Devices ◽  
The Individual ◽  
Human Limb

Aim: Intense training of arm movements using robotic devices can help reduce impairments in stroke. Recent evidence indicates that independent training of individual joints of the arm with robots can be as effective as coordinated multi-joint arm training. This makes a case for designing and developing robots made for training individual joints, which can be simpler and more compact than the ones for coordinate multi-joint arm training. The design of such a robot is the aim of the work presented in this paper. Methods: An end-effector robot kinematic design was developed and the optimal robot link lengths were estimated using an optimization procedure. A simple algorithm for automatically detecting human limb parameters is proposed and its performance was evaluated through a simulation study. Results: A six-degrees-of-freedom end-effector robot with three actuated degrees-of-freedom and three non-actuated self-aligning degrees-of-freedom for safe assisted training of the individual joints (shoulder or elbow) of the human arm was conceived. The proposed robot has relaxed constraints on the relative positioning of the human limb with respect to the robot. The optimized link lengths chosen for the robot allow it to cover about 80% of the human limb’s workspace, and possess good overall manipulability. The simple estimation procedure was demonstrated to estimate human limb parameters with low bias and variance. Discussion: The proposed robot with three actuated and three non-actuated degrees-of-freedom has a compact structure suitable for both the left and right arms without any change to its structure. The proposed automatic estimation procedure allows the robot to safely apply forces and impose movements to the human limb, without the need for any manual measurements. Such compact robots have the highest potential for clinical translation

An Emergency Tracking Controller Design for a Manipulator After its Actuator Failure

2015 ◽  
Author(s):  
Elżbieta Jarzębowska ◽  
Adam Szewczyk
Keyword(s):  
Degrees Of Freedom ◽  
Controller Design ◽  
Actuator Failure ◽  
End Effector ◽  
Model Based ◽  
Rest Position ◽  
Control Goal ◽  
Tracking Controllers ◽  
Tracking Controller ◽  
Simulation Results

This paper presents a development of two model-based emergency tracking controllers which can be turned on when one of actuators of a system fails during motion. The system is represented by a manipulator possessing 3 degrees of freedom, which may work in horizontal or vertical planes. The control goal is to enable an end effector of a broken manipulator completing tracking a predefined task as good as possible and then get back to its rest position. Simulation results confirm good performance of the designed emergency tracking controllers.

Geometric Work of Manipulators and Path Planning Based on Minimum Energy Consumption

1992 ◽  
Vol 114 (3) ◽  
pp. 414-421 ◽  
Author(s):  
Li-Shan Chou ◽  
Shin-Min Song
Keyword(s):  
Energy Consumption ◽  
Path Planning ◽  
Minimum Energy ◽  
Dynamic Programming Method ◽  
Continuous Path ◽  
End Effector ◽  
Minimum Energy Consumption ◽  
Special Geometry ◽  
Pick And Place ◽  
Regular Open

The energy efficiency of the robots of today’s generation is in general very poor due to the existence of “geometric work.” The geometric work is geometry dependent and can be eliminate by adopting a special geometry which decouples the gravitational motion from the horizontal motions. Instead of adopting a special geometry, this paper studies the geometric work of a regular open-chained manipulator and applies it to the path planning for minimum energy consumption. For a given manipulator geometry and end-effector position, the zones of velocity with zero geometric work are determined analytically. A map which describes these zones of zero geometric work at various positions in workspace is then constructed for path planning with zero geometric work. The path planning for minimum energy consumption is generated by the dynamic programming method and the results are compared with the map of zero geometric work. It is found that the end-effector tends to move within the zones of zero geometric work as much as possible. If the end-effector has to cross the boundary of a zone at some point, it again moves within the zones after crossing the boundary. The presented method can also be used to arrange the pick and place positions for minimum travel energy consumption. That is, the two positions should be selected so that a continuous path which connects them with zero geometric work and with monotonously ascending or descending features is available.

scholarly journals A discrete path/trajectory planner for robotic arms

1989 ◽  
Vol 31 (1) ◽  
pp. 1-28 ◽  
Author(s):  
H. H. Tan ◽  
R. B. Potts
Keyword(s):  
Degrees Of Freedom ◽  
Minimum Cost ◽  
Challenging Problem ◽  
Final State ◽  
End Effector ◽  
Joint Torques ◽  
Robotic Arms ◽  
Joint Coordinates ◽  
Simulation Results

AbstractAn interesting and challenging problem in robotics is the off-line determination of the minimum cost path along which an end effector should move from a given initial to a given final state. This paper presents a discrete minimum cost path/trajectory planner which provides a general solution and allows for a range of constraints such as bounds on joint coordinates, joint velocities, joint torques and joint jerks. To demonstrate the practicability and feasibility of the planner, simulation results are presented for the Stanford manipulator using three and then the full six of its degrees of freedom. Simulation runs with two-link planar arms are also presented to enable a comparison with previously published results.

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