A Three Degree-of-Freedom Optical Orientation Measurement Method for Spherical Actuator Applications

Spherical Magnetic Dipole Actuator for Spacecraft Attitude Control

“…Sensing is another aspect that is not covered in this work, but is necessary for this device to function. Rotor position and orientation information is needed in the control laws and could likely be accomplished with hall effect sensors, though other sensing schemes have been examined [84][85][86][87][88][89][90]. In the end, an experimental model would be needed to validate this theoretical 38 work and bring this device closer to realization.…”

Closed-loop magnetic bearing and angular velocity control of a reaction sphere actuator

“…Conventionally, in the 3-DOF spherical actuator literature, force and torque calculations are carried out by applying a change of coordinates in the derived magnetic flux models, parametrized with a set of three Euler angles to account for the orientation of the rotor. Several non-contact based methods were proposed to measure the orientation of the spherical rotor including, for example, vision based approaches [52,16,53,54], a laser-based apparatus relaying on flat reflecting plate [55], or an artificial neural network technique, which maps distributed 2-axis and 3-axis magnetic flux density measurements to the instantaneous orientation of the rotor [56]. Computing the orientation is not an easy task and, in general, although the relation between current and force and torque is linear, the relation between the rotor orientation parameters and the rotor magnetic flux density is nonlinear.…”

Adaptive output feedback control for permanent magnet spherical motor by fuzzy approximation approach

“…In this section, to illustrate the validity of the suggested adaptive fuzzy control approach, the rotor dynamics of a PMSM, shown in (1)(2)(3)(4)(5), is simulated. According to [8][9] In this paper, an adaptive output feedback control for PMSM by fuzzy approximation approach has been suggested.…”

“…Many fruitful works have been done by many researchers in the aspects of magnetic field [1], torque model [2] and orientation measurement [3]. But so far there is no effective way to control the spherical motor precisely.…”