Encoder and method for determining a rotational relative position between two components and robot having such an encoder

A method for determining a rotational position of a first component relative to a second component by an encoder, the encoder comprising at least one first reading head arranged on the second component, and a drive unit having a drive element driven in rotation relative to the first component and to which at least one first magnetic disk is fastened and which is arranged on the first component, wherein the at least first magnetic disk has, on an end face facing the first reading head, at least one circumferential first track having a plurality of magnetic regions which are formed one behind the other in the circumferential direction of the first magnetic disk and which have alternating magnetization directions the method comprising:

• during rotation of the at least first magnetic disk relative to the first component. measuring, at the first reading head, the magnetization directions along the first track;
• detecting, at the first reading head, at least a first periodic pulse sequence based on the measured magnetization directions along the first track, and
• comparing the respective detected periodic pulse sequence with a reference pulse sequence with the same periodicity;
• determining at least a first phase difference between the respective detected periodic pulse sequence and the reference pulse sequence based on the comparison;
• and
• determining a rotational position of the first component relative to the second component based on the at least first phase difference.