3-DOF Micro Research Articles

3-DoF zero power micro vibration isolation via linear matrix inequalities based on [formula omitted] and [formula omitted] control approaches

Zero-power micro vibration isolators based on hybrid electromagnets, consisting of coils and permanent magnets, have potential usage in many industrial and academic fields, such as space laboratory operations in orbit, micro-nano assembly, clean room design, bio-engineering, stewart platforms, transportation, semiconductor manufacturing, suspension system design, and robotic surgery platforms etc. due to providing mechanical contact free micro vibration isolation with comparatively low energy consumption. Classical controllers optimized in time-domain do not show satisfying disturbance rejection performance for multi-directional mechanical disturbances varying at different frequencies. To tackle this problem, optimization techniques in frequency-domain are needed. In recent years, linear matrix inequality (LMI) based controllers have received lots of attention and become very popular due to their ability to satisfy multi-objective frequency-domain requirements. However, an experimental research including LMI based H∞ and H2 feedback controllers for a zero-power 3-DoF micro vibration isolator has not been conducted so far. In this study, H∞ and H2 controller types are employed to minimize the H∞ and H2 norms of both ground and direct disturbances for 3-DoF micro-scale vibration isolation with zero-power objective. Moreover, the experimental setup has been designed and manufactured to meet aforementioned goals. The design parameters of the experimental setup are explicitly given. The effectiveness of the proposed LMI structures for 3-DoF micro vibration isolation with zero-power problem is shown with the experimental results.

Autonomous Control Agents for Adaptive MAV Mission Profiles

When a mission profile of an unmanned micro air vehicle is known a priori, one of the strategies adopted in autonomous control is to first generate a compatible trajectory in off-line and then implement a controller to track the trajectory. However, in decision rich intelligent aerial robots and in 6DOF operations of unmanned aerial vehicles, the mission profiles are usually known during an operation. Hence the trajectories are instantaneously inferred. Here an adaptive controller with capabilities to track these trajectories is required. In this paper, it is shown that an extended Kalman filter is an excellent tool to design such a controller which accepts the trajectory generation module as an input and then reconstructs its trajectories. To illustrate this feature, a 3DOF micro air vehicle in pitch plane is considered and an adaptive controller (referred as autonomous control agent) using an extended Kalman filter is applied to infer typical adaptive mission profiles.

Gain-scheduled robust control of a novel 3-DOF micro parallel positioning platform via a dual stage servo system

This paper presents a gain-scheduled robust control of a micro positioning platform using a dual stage servo system, which recently has been developed to achieve the 3-DOF motions ( x- and y-translations and α-tilting) with the accuracy to the sub-micrometer. The proposed platform consists of three sets of two-stage actuators: AC servo motors with ball screw for rough positioning and piezo actuators for fine positioning. Unlike existing parallel mechanisms using dual servo systems, the proposed platform is unique due to the fact that the actuation directions of the coarse and fine actuators are vertical with respect to each other, which enables them to effectively increase the mobility and resolution of the platform. While a well-known PI controller was adopted to establish the coarse control system due to its simplicity and reasonable performance, a gain-scheduled H ∞ controller was also employed to robustly ensure the desired accuracy of the fine control system. Since the coarse actuator is relatively slow and the mass of the proposed platform is negligible, the PI controller design for the coarse system is based on the kinematics of the proposed platform. Conversely, a physics-based dynamic model for the fine system is derived from a non-parametric system identification in order to match the experimental data well. Based on the combination of coarse and fine controllers, a dual servo control system is proposed, which sequentially selects the controller according to the pose of the proposed platform such as rotational angle, vertical and horizontal position. The successful performance of the synthesized controllers was verified through extensive experiments.

F-1220 薄板折り曲げ加工による並進3自由度マイクロパラレルメカニズム : 第1報 : 基本概念とプロトタイプ(S46-1 マイクロ・ナノ作業(1))(S46 マイクロ・ナノ作業)

F-1220 薄板折り曲げ加工による並進3自由度マイクロパラレルメカニズム : 第1報 : 基本概念とプロトタイプ(S46-1 マイクロ・ナノ作業(1))(S46 マイクロ・ナノ作業)