Open-Loop Control of a Flexible Manipulator With Two Links: Experimental Results

Author(s):  
G. Mimmi ◽  
L. Frosini ◽  
P. Pennacchi ◽  
C. Rottenbacher

Abstract This paper describes the experimental results of an open-loop control technique applied to a flexible manipulator, specially designed for space duties, in order to reduce the residual vibrations at the end of the positioning. The experimental set-up is a system with two flexible links with rectangular section connected by rotational joints. First, the experimental identification of the system parameters has been carried out. Then, four different motion inputs have been implemented. The performances of these motion inputs are compared in terms of residual vibration at the end of the positioning. The experimental results confirm the effectiveness of the motion input pre-shaping technique in the reduction of the residual vibrations.

2004 ◽  
Vol 11 (3-4) ◽  
pp. 377-382 ◽  
Author(s):  
Paolo Pennacchi

Open-loop control techniques, such as command input preshaping, are quite sensible to modelling errors and noise. In the paper, an analysis and a discussion about the robustness of the technique with respect to the errors than can affect estimation of the values of the system parameters is presented.


2019 ◽  
Vol 34 ◽  
Author(s):  
Meng-Cheng Lau ◽  
John Anderson ◽  
Jacky Baltes

Abstract This paper presents our sketch drawing artist humanoid robot research. One of the limitations of the existing artist humanoid robot is the lack of feedback on the error that occurs during the drawing process. The contribution of this research is the development of a humanoid robot artist with drawing error correction capability. Based on our previous work with open-loop control pen-and-ink humanoid robot artist, we have implemented a closed-loop visual servoing approach to address this problem. Our experimental results show that this approach is sufficient to correct drawing errors that occur due to mechanical limitation of a robot.


Author(s):  
Jau-Liang Chen ◽  
Yan-Ming Chen

The purpose of this research is trying to design a 6 degree-of-freedom micro-precision positioning stage with monolithic mechanism. It is hoped that this stage can reach 10 μm strokes along linear axis and with rotational angle no less than 50 μrad. The dimension of this positioning stage should be less than 200 mm × 200 mm × 50 mm. By using flexure hinge and piezoelectric actuator, this stage can achieve nanometer resolution. From the experimental results, it is found that the stage can achieve a maximum displacement of 29.3 μm in X axis; 11.94 μm in Y axis; and 6.74 μm in Z axis. The stage can also achieve a maximum rotation of 405.41 μrad around Z axis; 57.18 μrad around X axis; and 63.72 μrad around Y axis. With open loop control, we have shown that the minimum step for the stage is 110 nm in X-axis; 45 nm in Y axis; and 30 nm in Z-axis.


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