Design and construction of the magnetic driving vehicle in a two-dimensional testbed

Abstract

A two-dimensional testbed that aims to demonstrate the feasibility of magnetically driving several spacecrafts was successfully constructed. The testbed has two vehicles, each of which consists of two Bi2223 coils placed in an orthogonal way. The magnetic force between the two vehicles with a 1 m separation distance is less than 1 N, which is big enough to attract, repel and rotate two 50 kg vehicles in a 1.2 m × 2 m platform. The hardware for the testbed, which includes the coils, a cryostat and an air pressured system, is introduced. A parallel power supply circuit was specifically designed for the high temperature superconductor (HTS) coil operating in space, for the purpose of reducing the Joule heat and providing redundancy. Two key questions relating to the HTS coil used in the magnetic driving are discussed. First, the magnetic force between the two coils, a preliminary index directing the coil parameters, is concisely expressed as an arithmetical equation. The accuracy of the equation is checked by a more accurate model based on the Biot–Savart law and a FEA calculation. Second, the interaction between the orthogonal coils with respect to the Ic(B) characteristic of the Bi2223 tape is discussed. A minimum safe distance between the two coils is defined and numerically calculated. Two coils whose separation distance is larger than the minimum safe distance can be regarded as having no magnetic interaction.

Design of HTS Coil for Magnetic Driving Spacecraft

“…A more accurate model for force calculation is also available in [5]. The total mass is contributed from three parts: the satellite dry mass which is independent of propulsion system; the mass of HTS coils ; and the mass of cryocooler which depends on specific cryocooler type and coil size.…”

“…As reported in [12], long decay measurement has been carried out for a closed Bi2223 coil for more than two months. Solving the (4) gets the current in each turn of the coil as: (5) Multiplying the to both sides of the (5) gets the total Ampereturn of the coil as: (6) It is found that the total Ampere-turn which is responsible for generating local fields is independent to the number of the turn but only a function of the coil radius. The field generated by an Helmholtz coil at the center is (7) Substituting (6) to (7) and imposing the background field, we immediately get the field shielded by a single-stage APSC at the center.…”

“…The most intensive interaction occurs at the cross points. Referring to characteristic of Bi2223 tapes, a minimum safe distance is defined and solved in [5]. One 220 V line and four control lines connect the vehicle from the outside.…”

“…Although very thin, they are the only disturbing sources, but approved to be negligible compared with magnetic force. More specific designs and construction procedures are given in the previous publication [5].…”

Design and analysis of a hybrid magnetic shielding system: application for the magnetic non-destructive testing of circuits

“…With the rapid development of weak magnetic signal detection, high-precision magnetic sensors, such as superconducting quantum interference devices (SQUIDs), have been widely used. With the use of these detectors, the accuracy of magnetic field detection has been highly improved and they are applied in various domains, including encephalography [1], spacecraft [2] and crack detection [3]. In these areas, magnetic non-destructive testing is a core concept and has been a popular concern for its research value and business prospects.…”