Novel Measurement Method for Determining Mass Characteristics of Pico-Satellites

Abstract

Abstract:The centroid and moment of inertia directly affect the dynamic characteristics of aircraft, and accurate mass characteristic measurements are crucial to adequately control aircraft attitude. This paper proposes a new measurement method for determining aircraft mass characteristics that can improve measurement precision when used in regard to pico-satellites. The measurement system is designed according to the principles of three-point measure and constant torque. The feasibility of the test method of this study for determining the mass characteristics is proved by using a dynamic simulation and an experimental analysis method. Through a number of standard workpiece tests, the deviation of the measurement system and effective compensation methods of the mass characteristics are obtained. The measurement system and compensation methods are applied to measure the mass characteristics of a pico-satellite, which can be detected by only one time clamping. The measurement system proposed herein can effectively improve measurement precision, as it was found that the accuracy of the centroid and the moment of inertia of the pico-satellite are less than 1 mm and 1.5 × 10 −2 kgm 2 , respectively. The proposed measurement system also has many advantages, such as a simple operation, high efficiency, small volume, and low cost.

A demodulation algorithm for processing rotational inertia signals using a torsion pendulum method based on differentiation and resonance frequency analysis

“…No matter which kind of oscillation method is adopted, oscillation movement is detected by displacement sensors, and the rotational inertia of a test object is calculated based on the fact that the rotational inertia about the center axis of a pendulum is proportional to the square of the oscillation period. Nowadays, the research in inertia property measurement technologies mainly focuses on the damping effect of oscillation movement and measurement error compensation technology [16,17], the integrated mass characteristics (properties) measurement method [18,19], the inertia measurement method for large and heavy objects [20,21], and in-orbit identification technology of inertia parameters for spacecraft [22,23]. For example, Zhao [16] et al presented a method to estimate instantaneous undamped natural frequency and a nonlinear damping coefficient for determining rotational inertia accurately.…”

“…For example, Zhao [16] et al presented a method to estimate instantaneous undamped natural frequency and a nonlinear damping coefficient for determining rotational inertia accurately. Teng [18] et al developed a measurement system that combined the multipoint weighing method and the torsion pendulum method to determine all the pertinent mass characteristics of a pico-satellite. Brancati [20] et al developed a system equipped with three incremental encoders and an inertial measurement unit to statically or dynamically determine the inertia parameters of large-sized objects, and a case of inertia property measurement for a car was presented.…”

Inertia property determination by spectrum analysis of damped oscillation detection signal

“…Nowadays, most of the research works on inertia measurement technology focus on the measurement method of inertia properties for large size objects and the integrated measurement method of mass characteristics. For example, Teng et al [29] developed a measurement system based on the principles of three-point measurement and constant torque (torsion pendulum method). This measurement system can determine all mass characteristics of an aircraft.…”

“…For example, Teng et al. [29] developed a measurement system based on the principles of three‐point measurement and constant torque (torsion pendulum method). This measurement system can determine all mass characteristics of an aircraft.…”

Collaborative robot zero moment control for direct teaching based on self-measured gravity and friction

“…Traditional industrial robots cannot satisfy this requirement, however this study presents a zero moment control 1 technology based on moment compensation. 2 It can be applied to the direct teaching of the robot, 3,4 which can eliminate the need for a high-cost multidimensional moment sensor 5 and make the teaching easy and accurate.…”