Development of a Hexapod Laser-based Metrology System for Finer Optical Beam Pointing Control

Chen, Hong-Jen; Agrawal, Brij N.

doi:10.2514/6.2004-3146

Cited by 7 publications

(3 citation statements)

References 2 publications

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“…A spring is added to each driving column to isolate some high-frequency vibration, and the positive feedback of force is used to improve the closed-loop robustness and reduce the system sensitivity so as to further improve the vibration isolation effect. The Naval Postgraduate School (NPS) designed the NPS flexible Stewart platform with an electro-magnetic soft actuator to isolate micro-vibration on spacecraft (Figure 14i) [121]. This platform has the characteristics of large driving displacement and perfect vibration isolation effect but requires additional support structure during launch.…”

Section: Future Development Prospectsmentioning

confidence: 99%

Progress of Stewart Vibration Platform in Aerospace Micro–Vibration Control

Feng

Zhu

et al. 2022

Aerospace

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In order to support the development of high–precision spacecraft, the current state of the Stewart vibration isolation platform in the field of aerospace micro–vibration was surveyed. First, based on analyses of the causes and characteristics of spacecraft micro–vibration, the principles, characteristics, advantages and disadvantages of four vibration isolation technologies are summarized. Second, the development process of the Stewart vibration isolation platform, from structural proposal and theoretical calculation to application in various fields, is introduced. Then, the current state of kinematics, dynamics and braking control algorithms of the Stewart platform is investigated, and related work on rigid/flexible platforms in the field of aerospace micro–vibration is introduced in detail. Finally, the idea that the Stewart platform can be fabricated by 4D printing technology is proposed. The novel Stewart platform can be combined with artificial intelligence algorithms and advanced control strategies, allowing for further development in the direction of an integrated omnidirectional, full–frequency and multi–function platform with variable stiffness.

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Section: Future Development Prospectsmentioning

confidence: 99%

Progress of Stewart Vibration Platform in Aerospace Micro–Vibration Control

Feng

Zhu

et al. 2022

Aerospace

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“…Such a setup can also be extended to stereo vision, where both cameras need to be moved parallel to each other around their centers [104]. Gough-Stewart platforms (Figure 3c) and variations thereof feature more than the two or three DoFs required for a typical pointing mechanism but are equally often used for this purpose [105][106][107][108][109][110][111]. Piezo-actuators in the legs of this type of platform can provide high accuracy, but only a limited range of motion.…”

Section: Pointing Mechanismsmentioning

confidence: 99%

High-Precision Low-Cost Gimballing Platform for Long-Range Railway Obstacle Detection

Assaf

Cornelius

Cadena

et al. 2022

Sensors

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Increasing demand for rail transportation results transportation by rail, resulting in denser and more high-speed usage of the existing railway network, making makes new and more advanced vehicle safety systems necessary. Furthermore, high traveling speeds and the greatlarge weights of trains lead to long braking distances—all of which necessitates Long braking distances, due to high travelling speeds and the massive weight of trains, necessitate a Long-Range Obstacle Detection (LROD) system, capable of detecting humans and other objects more than 1000 m in advance. According to current research, only a few sensor modalities are capable of reaching this far and recording sufficiently accurate enoughdata to distinguish individual objects. The limitation of these sensors, such as a 1D-Light Detection and Ranging (LiDAR), is however a very narrow Field of View (FoV), making it necessary to use ahigh-precision means of orienting to target them at possible areas of interest. To close this research gap, this paper presents a novel approach to detecting railway obstacles by developinga high-precision pointing mechanism, for the use in a future novel railway obstacle detection system In this work such a high-precision pointing mechanism is developed, capable of targeting aiming a 1D-LiDAR at humans or objects at the required distance. This approach addresses To address the challenges of a low target pricelimited budget, restricted access to high-precision machinery and equipment as well as unique requirements of our target application., a novel pointing mechanism has been designed and developed. By combining established elements from 3D printers and Computer Numerical Control (CNC) machines with a double-hinged lever system, simple and cheaplow-cost components are capable of precisely orienting an arbitrary sensor platform. The system’s actual pointing accuracy has been evaluated using a controlled, in-door, long-range experiment. The device was able to demonstrate a precision of 6.179 mdeg, which is at the limit of the measurable precision of the designed experiment.

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“…The James Webb space telescope, terrestrial planet finder, space based laser, space-based interferometer and deep-space laser communication are such examples where the micro-radian pointing and nanometer level of motion stability are required by (Ford, et al, 2005), (Chen, et al, 2004) and (Winthrop, et al 2003). On the other hand, the space systems may contains many vibration sources.…”

Section: Introductionmentioning

confidence: 99%