This paper presents the results of a series of experimental tests carried out on the Space Robot Simulator assembly, in order to minimize vibrations of a flexible manipulator for space applications which has been set up at the Department of Structural Mechanics of Università di Pavia, Italy. In particular, the task of the experiments was to test the effectiveness of the command input shaping technique on the vibration reduction, for the open loop control of a flexible manipulator. Input shaping is a method for reducing residual vibrations in high-performance controlled machines. This method requires a simple system model consisting of estimates of the first natural frequencies and damping ratios. Input shaping generates vibration-reducing shaped commands through convolution of a pulse sequence with the desired command. In other words, through the knowledge of the vibrating system, this approach is intended to reduce the final vibration by suitably modifying the actuator inputs. The performance of the input shaper is measured by comparing the residual vibration obtained by the shaped command with the residual vibration obtained by the unshaped command. The aim of this new research is to highlight the effectiveness of the motion input pre-shaping techniques with experimental comparisons between traditionally designed input shapers (IS) and extra-insensitive input shapers (EI), in terms of insensitivity. The technique results in command profiles that are significantly more insensitive to modelling errors or parameter variations than those previously reported. The control technique is verified both with computer simulations and hardware experiments. This work is part of an ASI (Agenzia Spaziale Italiana) multi-objective research project with the aim to design and realize experimental devices for the on orbit validation of control techniques applied to flexible articulated systems.

Vibration Reduction in Robotic Arm Dynamics: Theoretical and Experimental Comparison of Input Shapers

MIMMI, GIOVANNI;ROTTENBACHER, CARLO EUGENIO ALESSANDRO;REGAZZONI, MANUEL
2006-01-01

Abstract

This paper presents the results of a series of experimental tests carried out on the Space Robot Simulator assembly, in order to minimize vibrations of a flexible manipulator for space applications which has been set up at the Department of Structural Mechanics of Università di Pavia, Italy. In particular, the task of the experiments was to test the effectiveness of the command input shaping technique on the vibration reduction, for the open loop control of a flexible manipulator. Input shaping is a method for reducing residual vibrations in high-performance controlled machines. This method requires a simple system model consisting of estimates of the first natural frequencies and damping ratios. Input shaping generates vibration-reducing shaped commands through convolution of a pulse sequence with the desired command. In other words, through the knowledge of the vibrating system, this approach is intended to reduce the final vibration by suitably modifying the actuator inputs. The performance of the input shaper is measured by comparing the residual vibration obtained by the shaped command with the residual vibration obtained by the unshaped command. The aim of this new research is to highlight the effectiveness of the motion input pre-shaping techniques with experimental comparisons between traditionally designed input shapers (IS) and extra-insensitive input shapers (EI), in terms of insensitivity. The technique results in command profiles that are significantly more insensitive to modelling errors or parameter variations than those previously reported. The control technique is verified both with computer simulations and hardware experiments. This work is part of an ASI (Agenzia Spaziale Italiana) multi-objective research project with the aim to design and realize experimental devices for the on orbit validation of control techniques applied to flexible articulated systems.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11571/31499
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