Dynamics and control of a parallel mechanism for active vibration isolation in space station

Abstract

Vibration in the microgravity environment is with the characteristics of low frequency, small amplitude, and randomness. Control method of an active vibration isolation system with parallel mechanism applied to space application, which is effective for disturbance suppression, is proposed. The dynamics model of active vibration isolation system with payload is represented via Kane's method, thereafter the description in state-space linearization is introduced. System properties and step responses of the systems in open loop are evaluated in detail. Controllability and observability of the system are checked by state-space equations of the system. The state feedback decoupling with double-loop proportionalintegral-derivative (PID) control method is adopted as the system controller to design the decoupling matrix

Free-flying dynamics and control of an astronaut assistant robot based on fuzzy sliding mode algorithm

“…When using traditional sliding mode control law formula (20) and formula (21), we choose c ¼ 10, 2 ; we consider that the maximal trust of one ducted fan is 2.7 N, and each degree of freedom has two ducted fans to drive the robot at most. So, in order to guarantee the exploitativeness of the designing scheme, we set the maximal output thrust of each degree of freedom to be 5 N. Through simulation, the 3D curves diagram that the AAR-2 tracks the space circular trajectory is shown in Fig.…”

“…It can greatly reduce the workload of astronauts and improve their work efficiency. In addition, if the robot can realize free flight in-cabin, it would also have the capacity to take advantage of the high level microgravity environment to complete some scientific experiments such as vibration isolation experiments [2], small satellites formation experiments and spacecraft rendezvous and docking experiments [3]. Therefore, this kind of in-cabin space robot has a high application value.…”

Modeling and Dynamics of a MDOF Isolation System

“…[6][7][8]. In most cases in vibration isolation, better isolation effectiveness can be obtained by using elements with smaller restoring forces which result in smaller natural frequency of the system, especially for microgravity environment in aerospace engineering [9][10][11].…”

“…For the MDOF vibration isolation platform, active controllers are the chief method [9][10][11][21][22][23][24][25][26][27]. The key point of the mechanism of active control in MDOF isolator is to generate anti-vibration forces in different directions by actuators and sensors in the designed system.…”

Attitude control for astronaut assisted robot in the space station

“…(b) Isolating vibration effectively to carry scientific experimental loads. Compared to the traditional isolation platform currently used in ISS [7], the cabin floating platform does not need complex technology to create a high-level microgravity environment, and the experimental device is convenient and flexible.…”