A Low-Cost Three-Degree-of-Freedom Position Measurement Method of the Y-Type Maglev Planar Motor Based on Hall Sensor

Maglev planar motors are critical transportation equipment in the industrial field. The existing positioning methods of magnetic levitation planar motors are costly and complex, which makes it difficult to meet the requirements of equipment development and testing in the laboratory environment. This article presents a three-degree-of-freedom (DOF) (translation along the x-axis and y-axis and rotation about the z-axis) position measurement method for the mover of Y-type magnetic levitation planar motor based on Hall sensors. The position-solving algorithm of the proposed method calculates the position by decoupling three DOF by measuring three 1-D-phase angles. Compared with optical methods, such as laser interferometers or planar gratings, this method has a simpler device structure and lower cost. Motion simulations and experiments were presented, and the three-DOF position [<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\alpha $ </tex-math></inline-formula>, x, y] was solved by the proposed method. The results of the experiments show that the resolutions of translational and rotational motions are 5-<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> m scale and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10'$ </tex-math></inline-formula> scale, respectively. The absolute maximum errors of [<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\alpha $ </tex-math></inline-formula>, x, y] are <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10'$ </tex-math></inline-formula>, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5~\mu $ </tex-math></inline-formula> m, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5~\mu $ </tex-math></inline-formula> m with the comparison of reference eddy current sensors.