Magnetic moment orientation compensation of a magnetic navigated underactuated spherical capsule robot for all-around observation.

All-around disease screening in any appointed position in 3D regions of the gastrointestinal (GI) tract such as esophagus, stomach and colon is still a pending issue. Based on the rotating magnetic coaxial effect of a suspended magnet actuated by the spatial universal rotating magnetic field (SURMF), a novel underactuated spherical capsule robot(USCR) with fully suspended magnetic ring in term of the gyroscope dynamic balance, along with its lateral drive method using rotating coaxial magnetic moment, are proposed to address orthogonal decoupling of magnetic moments, flexible and efficient posture control with good stability. The underactuated structure facilitates the all around observation mode at a fixed-point and the rolling locomotion mode by the space universal rotating magnetic field (SURMF) axis manipulation, however, magnetic moment orientation deviation and motion path deviation are caused by the slip angle, thus deviation model of the decoupled rotating coaxial magnetic moment is derived, corrected and verified, which lays a foundation for the precise and stable control of the motion path by the slip angle compensation and the application of the rotating coaxial driving theory of the novel capsule.