Time-Optimal Control of Two Robots Holding the Same Workpiece

1993 ◽  
Vol 115 (3) ◽  
pp. 441-446 ◽  
Author(s):  
J. E. Bobrow ◽  
J. M. McCarthy ◽  
V. K. Chu
Keyword(s):  
Optimal Control ◽  
Contact Force ◽  
Degrees Of Freedom ◽  
Unique Feature ◽  
Robot Arm ◽  
Robot System ◽  
Motion Constraints ◽  
Time Optimal ◽  
Internal Forces ◽  
Constrained Robot

An algorithm is given which minimizes the time for two robots holding the same workpiece to move along a given path. The unique feature of these systems is that they have more actuators than degrees of freedom. The method can be applied to any constrained robot system, including the case where one robot arm moves in contact with a surface. In addition to finding the optimum torque histories, the algorithm determines the optimum contact force between the each robot and the workpiece throughout the motion. Constraints on these internal forces are easily introduced into the algorithm.

scholarly journals Development of a Robotic Arm for Automated Harvesting of Asparagus

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Yuki Funami ◽  
Shinji Kawakura ◽  
Kotaro Tadano
Keyword(s):  
Input Data ◽  
Degrees Of Freedom ◽  
Robotic Arm ◽  
Pneumatic Cylinder ◽  
Agricultural Crops ◽  
Robot Arm ◽  
Linkage Mechanism ◽  
Robot System ◽  
Wheeled Robot ◽  
Agricultural Setting

We designed and developed an original arm-robot system that harvests asparagus in both outdoor and indoor agricultural fields. Using the system, we carried out harvesting work automatically with input data related to asparagus vegetation in restricted settings. The developed fixed-site (non-wheeled) robot can reach out its arm to a stem of asparagus from a passage between two ridges on cultivated farmland without touching non-target stems or requiring changes to the farm conditions. Additionally, the hand at the tip of the arm stably grasps, cuts, harvests, and throws the stem it into a specific bag made for the gathering of agricultural crops. In mechanical terms, our originally developed robot arm has four degrees of freedom and is driven by motors. It harvests target asparagus stems without coming into contact with other objects in an agricultural setting, and the hand using the linkage mechanism of a pneumatic cylinder driven by air pressure, can hold the stem firmly and cut it. Our repetitive verification experiments showed that the mechanism is sufficiently accurate. The present study confirmed the robot arm system could be used for automatically harvesting asparagus, and the system was endorsed by several farmers. Moreover, we carried out experiments of harvesting asparagus on actual outdoor land and successfully harvested three stems sequentially under the condition that the operator obtained the positional coordinates earlier.

scholarly journals Minimum time optimal control simulation of a GP2 race car

2017 ◽  
Vol 232 (9) ◽  
pp. 1180-1195 ◽  
Author(s):  
Nicola Dal Bianco ◽  
Roberto Lot ◽  
Marco Gadola
Keyword(s):  
Optimal Control ◽  
Degrees Of Freedom ◽  
Load Transfer ◽  
Control Method ◽  
Multibody Model ◽  
Race Car ◽  
Optimal Control Method ◽  
Time Problem ◽  
Time Optimal ◽  
The Impact

In this work, optimal control theory is applied to minimum lap time simulation of a GP2 car, using a multibody car model with enhanced load transfer dynamics. The mathematical multibody model is formulated with use of the symbolic algebra software MBSymba and it comprises 14 degrees of freedom, including full chassis motion, suspension travels and wheel spins. The kinematics of the suspension is exhaustively analysed and the impact of tyre longitudinal and lateral forces in determining vehicle trim is demonstrated. An indirect optimal control method is then used to solve the minimum lap time problem. Simulation outcomes are compared with experimental data acquired during a qualifying lap at Montmeló circuit (Barcelona) in the 2012 GP2 season. Results demonstrate the reliability of the model, suggesting it can be used to optimise car settings (such as gearing and aerodynamic setup) before executing track tests.

Time-optimal Trajectories for Robot Manipulators

Robotica ◽  
1991 ◽  
Vol 9 (2) ◽  
pp. 131-138 ◽  
Author(s):  
M. W. M. G. Dissanayake ◽  
C. J. Goh ◽  
N. Phan-Thien
Keyword(s):  
Optimal Control ◽  
Robot Manipulators ◽  
Optimal Trajectories ◽  
Computational Technique ◽  
Robot Arm ◽  
Physical Explanation ◽  
Design Constraints ◽  
Numerical Examples ◽  
Time Optimal ◽  
Planar Robot

SUMMARYA computational technique for obtaining minimum-time trajectories for robot manipulators is described in this paper. In the analysis, limitations to link movements due to design constraints are taken into consideration. Numerical examples based on a two-link planar robot arm shows the feasibility of the technique proposed. A physical explanation for the general characteristics of the observed trajectories is also presented. The importance of appreciating optimal control issues in designing robot manipulators and in planning robot workstation layouts is emphasised.

A sealing robot system with visual seam tracking

Robotica ◽  
1984 ◽  
Vol 2 (1) ◽  
pp. 41-46 ◽  
Author(s):  
Susumu Sawano ◽  
Junichi Ikeda ◽  
Noriyuki Utsumi ◽  
Yukio Ohtani ◽  
Akira Kikuchi ◽  
...  
Keyword(s):  
Solid State ◽  
Degrees Of Freedom ◽  
Seam Tracking ◽  
Robot Hand ◽  
Robot Arm ◽  
Test Results ◽  
Robot System ◽  
Car Body ◽  
Flexible Mechanism

SUMMARYA new robot system has been introduced which was designed to seal the seams of car body panels. The system has nine degrees of freedom, and includes the following features: (1) A seam tracking servo using a solid-state TV camera is mounted at the robot hand to compensate for the seam deviations. (2) The robot arm is equipped with a flexible mechanism at the wrist to provide a wide working range for the seal nozzle. (3) A two axis orthogonal robot carrier is provided to make the robot follow the work on an indexed conveyor during the sealing operation. This paper deals with the structure and operation of the system and presents test results obtained on a sealing line.

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