Microgravity Performance Evaluation for Zero Gravity Robot in China's Space Station gas of the air-jet thrusters comes from a gas storage cylinder, which can support the air-jet thrusters working continuously for no less than one hour and can be reinflated. The electromagnetic actuators consist ofpermanent magnets fixed on the inner body and two sets oforthogonal coils fixed on the outer body, which can generate force in two DOF. The electric unit mounted on the outer body is used for calculations related to the motion control ofthe inner body and the outer body, as well as the reception and transmission of instructions and data. The energy components include some lithium batteries mounted on the outer body and a wireless energy transfer device placed between the inner body and the outer body. The lithium batteries supply power to the outer body directly and supply power to the inner body through wireless transmission. The communication components include two sets of wireless-fidelity components mounted on the inner body and the outer body, and one set of infrared transceiver module placed between them. The sensors and actuators of ZGR is listed in Table I. The frequency responses of the sensors are the measurement frequencies, and the frequency responses of the actuators are the output frequencies. Figure 3. Main components ofZGR. accelerometers are used for high-accuracy measurement of microgravity acceleration of the inner body. The 2DPSDs measure the relative motion between the inner body and the outer body. The actuators include 24 air-jet thrusters mounted on the outer body and three sets of electromagnetic actuators placed between the inner body and the outer body. The Table 1. Sensors and Actuators of ZGR Component Sensor Cameras MEMS Three-axis electrostatic-levitation accelerometers 2D-PSDs Actuator Air-jet thrusters Electromagnetic actuators WORKING MODES There are three working modes for ZGR, including an outside-rack air-suspension mode, an inside-rack air-suspension mode, and an inside-rack magnetic-levitation mode. The outside-rack air-suspension mode is designed to operate ZGR out ofHMLR (directly inside TH) under the spatial constraints of500 mm and10. The inside-rack air-suspension mode is designed to operate ZGR by the air-jet thrusters and electromagnetic actuators in HMLR Frequency response Accuracy 10 Hz 50 Hz 20 Hz 100 Hz 4 Hz 50 Hz 0.59 mm and 0.07 inside the rack 5.15 mm and 0.23 outside the rack 0.25/h and 1.910-5 m/s2 110-6-510-7 m/s2/Hz1/2 @ 0.01-0.1 Hz 510-7-510-6 m/s2/Hz1/2 @ 0.1-5 Hz 50 mm (measurement accuracy of spot position) 50 mN 1%-1% (relative accuracy) @ 5 mN-5 N 34 IEEE A&E SYSTEMS MAGAZINE JANUARY 2022