A calibrator includes: a position calculator which calculates a relative position between a first detector and a second detector on the basis of detection signals acquired respectively from the first detector, the second detector, and a third detector positioned with respect to a scale attached to a rotating body; and an error calculator which calculates error information on rotational position information of the rotating body on the basis of the relative position calculated by the position calculator as well as the detection signals.

A calibrator includes: a position calculator which calculates a relative position between a first detector and a second detector on the basis of detection signals acquired respectively from the first detector, the second detector, and a third detector positioned with respect to a scale attached to a rotating body; and an error calculator which calculates error information on rotational position information of the rotating body on the basis of the relative position calculated by the position calculator as well as the detection signals.

There is provided an optical encoder including a photodiode array and a code disk opposite to each other. The photodiode array includes at least three sets of position photodiodes and two index photodiodes arranged transversally. The two index photodiodes are adjacently arranged at the same side of the at least three sets of position photodiodes. A first set of position photodiodes and a last set of position photodiodes of the at least three sets of position photodiodes are partially covered to alleviate the total harmonic distortion. The rest position photodiodes of the at least three sets of position photodiodes other than the first and last sets of position photodiodes are not covered.

An encoder, comprising a first element, a second element, and a plurality of components, in which the first element is movable among a plurality of positions relative to the second element, each position is adjacent to at least one other position, each component generates a signal at each of said positions, and movement of the first element from any position to any adjacent position results in a change in a signal from only one of said components. Also, an encoder that comprises a multi-detector element which comprises two or more sub-detectors that generate sub-signals, the sub-detectors spaced from each other a distance (rotational and/or translational) that is smaller than a distance between two positions of a first element. Also, a method of detecting a position of a first element relative to a second element, comprising moving a first element relative to a second element from a first position to a second position.

A control knob assembly for a consumer appliance is provided. The control knob assembly provides a compact means for determining the angular position of the control knob and illuminating a plurality of indicators to communicate that angular position to a user of the appliance. More specifically, the control knob assembly includes an optical encoder disc that defines a plurality of teeth that are in operable communication with a plurality of optical sensors. The position of the sensors and the spacing of the plurality of teeth are configured to generate signals as the control knob is rotated that allow for the precise determination of the angular position of the control knob. Moreover, the optical encoder disc may fit inside a lighting assembly and may have a low profile, resulting in a compact control knob assembly that may easily fit within the area underneath the control knob and control panel.

Disclosed is a method for estimating angular errors of coders for a looped system including a rotating actuator and an angle coder producing a position measurement signal, and including a calculation device controlling the actuator, the calculation device receiving a setpoint signal, as well as the measurement signal, for looping, the calculation device calculating in a corrector a control signal. In a test phase, a specific corrector C.sub.ω.sub.rj(q) is synthesised for constant rotation speed ω.sub.rj, the corrector having substantially zero gain at the frequency and harmonics, resulting in opening the loop at the frequencies, a matrix relation is established between position measurements and a function of parameters characterizing the coder errors and the torque ripples, the test phase repeats with different speeds, the matrix relations are concatenated producing an identifiable global matrix relation, the encoder error and torque ripple parameters are estimated by resolution of the global matrix relation.

A rotary scale apparatus for an encoder apparatus including a planar disc on which at least one track including scale features is provided, in which the planar disc includes a hole through its centre for receiving a cylindrical shaft, and in which the rotary scale member includes at least three cantilevered spring members which are provided substantially in plane with the planar disc and spaced around the edge of the hole, for engaging with, and radially locating the disc on, a cylindrical shaft inserted therethrough.

There is provided an optical encoder including an encoding medium and a substrate. The encoding medium has a relative movement with respect to the substrate in a predetermined direction. The substrate includes an index photodiode and two control photodiodes. The index photodiode is arranged between the two control photodiodes along the predetermined direction. The output signals of the two control photodiodes are for controlling ON/OFF of gain regulation on an output signal of the index photodiode so as to turn on the gain regulation within an interval during which the index photodiode does not generate an index pulse but to turn off the gain regulation within an interval during which the index photodiode generates the index pulse.

An encoder includes a scale and a sensor. The scale has first and second absolute patterns. The sensor includes a light source, and first and second absolute light receivers. The first and second absolute light receivers receive light from the first and second absolute patterns, respectively. The first absolute light receiver receives light from the first pattern and includes first and second light receiving elements. Each first light receiving elements outputs a first signal with a first phase. Each second light receiving elements outputs a first signal with a second phase. The first and second light receiving elements are arranged alternately. The second absolute light receiver includes third and fourth light receiving elements. Each third light receiving element outputs a second signal with the first phase. The third and fourth light receiving elements are arranged alternately. Each fourth light receiving element outputs a second signal with the second phase.

There is provided an optical encoder with alignable relative positions between elements including an encoding medium, a sensor package and a memory. The sensor package includes a photodiode array and two alignment photodiodes opposite to the encoding medium. The memory records an alignment pattern associated with output signals of the two alignment photodiodes when the encoding medium and the sensor package are at nominal operating positions. When the encoding medium and the sensor package are not at the nominal operating positions, the relative position alignment is performed by adjusting current relative positions between the encoding medium and the sensor package to cause a current pattern associated with output signals of the two alignment photodiodes to be identical to the alignment pattern.