A technique for inversely identifying joint stiffnesses of robot arms via two-way TubeNets

Many kinds of robot arms with five degrees of freedom are widely used in industry for arc welding, spray painting, assembling etc. It is necessary to be able to compute joint displacements when such devices are computer controlled. A solution to this problem is presented and the analysis is illustrated by a numerical example using the most common industrial robot with five axes. Further, special cases are discussed using screw theory.

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Planning a minimum-time trajectories for robot arms

10.1109/robot.1985.1087233 ◽

2005 ◽

Cited By ~ 46

Author(s):

G. Sahar ◽

J. Hollerbach

Keyword(s):

Minimum Time ◽

Robot Arms

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Structural Optimization of Cantilever Mechanical Elements

Journal of Vibration and Acoustics ◽

10.1115/1.3269366 ◽

1986 ◽

Vol 108 (4) ◽

pp. 427-433 ◽

Cited By ~ 5

Author(s):

Eugene I. Rivin

Keyword(s):

Structural Optimization ◽

Natural Frequencies ◽

Superior Performance ◽

Vibration Absorbers ◽

Stability Margins ◽

Dynamic Vibration ◽

Robot Arms ◽

Limited Effectiveness ◽

Mass Ratios ◽

Dynamic Vibration Absorbers

Naturally limited stiffness of cantilever elements due to lack of constraint from other structural components, together with low structural damping, causes intensive and slow-decaying transient vibrations as well as low stability margins for self-excited vibrations. In cases of dimensional limitations (e.g., boring bars), such common antivibration means as dynamic vibration absorbers have limited effectiveness due to low mass ratios. This paper describes novel concepts of structural optimization of cantilever components by using combinations of rigid and light materials for their design. Two examples are given: tool holders (boring bars) and robot arms. Optimized boring bars demonstrate substantially increased natural frequencies, together with the possibility of greatly enhanced mass ratios for dynamic vibration absorbers. Machining tests with combination boring bars have been performed in comparison with conventional boring bars showing superior performance of the former. Computer optimization of combination-type robot arms has shown a potential of 10–60 percent reduction in tip-of-arm deflection, together with a commensurate reduction of driving torque for a given acceleration, and a higher natural frequencies (i.e., shorter transients). Optimization has been performed for various ratios of bending and joint compliance and various payloads.

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Dual scope method: A novel application of a simultaneous multi-image display system for a thoracoscopic robotic lobectomy

10.1510/mmcts.2021.049 ◽

2021 ◽

Keyword(s):

Thoracic Surgery ◽

Image Display ◽

The Novel ◽

Thoracic Cavity ◽

Display System ◽

Operative Field ◽

Robot Arms ◽

Simultaneous Visualization

The advantages of a multi-input display system platform in robotic thoracic surgery have not been well described. We report the novel application of a multi-display system for simultaneous visualization of an additional thoracoscopic image during a robotic lobectomy, which we have named the dual scope method. An additional thoracoscope is inserted from the bottom of the thoracic cavity. This thoracoscope visualizes the whole operative field, including the robot arms, from a bystander’s viewpoint. By providing an integrated image from the robot scope and the thoracoscope, various problems, such as arm collision, inappropriate instrument direction, excessive traction, and injury, can be solved or avoided much more easily and safely than with the use of the robotic image alone. The dual scope method facilitates the safety and efficiency of robotic lobectomy.

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