Takuya Kanzawa

Centrifuge rotor integrated analysis

The Centrifuge Rotor (CR) is a large life science experiment facility which will be installed in the International Space Station (ISS). It will provide artificial gravity of 2g or less by rotating up to 4 science habitats, and it will be the first such machinery to be used in space. To prevent vibration disturbance exchanges between the CR and the ISS, a soft 5 dof vibration isolation mechanism is used which cannot support the CR weight on the ground. Therefore, the CR on-orbit performance must be predicted by integrated analysis which must model all of the equipment including sensors, actuators, flexible structure, gyroscopic effects, and controllers. Here, we introduce the CR mechatronics, a verification procedure, and examples of the application of the integrated analysis which is based on the general-purpose mechanism analysis software ADAMS.

Fault-Tolerant Attitude Control System for a Spacecraft with Control Moment Gyros Using Multi-Objective Optimization

Recent years have seen a growing requirement for accurate and agile attitude control of spacecraft. To both quickly and accurately control the attitude of a spacecraft, Control Moment Gyros (CMGs) which can generate much higher torque than conventional spacecraft actuators are used as actuators of the spacecraft. The drive on the motors is needed for rapid maneuverability, negatively affecting their life. Thus, in designing spacecraft the conflicting requirements are rapid maneuverability and reduced the drive on motors. Furthermore, the attitude control system needs to be fault-tolerant. The dominant requirement is different for each spacecraft mission, and therefore the relationship between the requirements should be shown. In this study, a design method is proposed for the attitude control system, using multi objective optimization of the skew angle and parameters of the control system. Pareto solutions that can show the relationship between the requirements are obtained by optimizing the parameters. Through numerical analysis, the effect with fault-tolerance and parameter differences for the dominant requirement are confirmed and the method to guide for determining parameters of the attitude control system is established.

Fault-tolerant attitude control systems using multi-objective optimization for a spacecraft equipped with control moment gyros

In recent years, there has been a requirement for accurate and agile attitude control of spacecraft. To meet this demand there has been an increasing use of Control Moment Gyros (CMGs), which can generate much higher torque than reaction wheels that are used as conventional spacecraft actuators. The drive on the motors is needed for rapid maneuverability, negatively affecting their life. Thus, in designing spacecraft the conflicting requirements are rapid maneuverability and reduced the drive on motors for long operation life. Furthermore, the attitude control system needs to be fault-tolerant. The dominant requirement is different for each spacecraft mission, and therefore the relationship between the requirements should be shown. In this study, a design method is proposed for the attitude control system, using multi objective optimization of the skew angle and parameters of the control system. Pareto solutions that can show the relationship between the requirements are obtained by optimizing the parameters. Using numerical analysis, it is shown that an attitude control system appropriate to the dominant situation can be designed and the appropriate skew angle and parameters of the control system, which correspond to the considered requirements, can be confirmed by the proposed method.