Apparatus adapted to provide an indication of an angular position of an input member over multiple turns

Apparatus adapted to provide an indication of an angular position of an input member over multiple turns, the apparatus comprising:

• at least two rotatable members configured, in use, to rotate in accordance with rotation of an input member,
• at least one sensing device configured to measure and output an angular position of at least one of the rotatable members, and
• a device configured to use the angular position measurements from the at least one sensing device to produce an indication of an angular position of the input member over multiple turns,
• wherein the rotatable members are configured to rotate simultaneously but at different rates, and
• wherein the plurality of rotatable members each has a notional zero position and the device is configured to produce the position indication by computing how far the rotatable members have passed through from their zero positions.

Apparatus adapted to provide an indication of an angular position of an input member over multiple turns, the apparatus comprising:

• at least two rotatable members configured, in use, to rotate in accordance with rotation of an input member,
• at least one sensing device configured to measure and output an angular position of at least one of the rotatable members, and
• a device configured to use the angular position measurements from the at least one sensing device to produce an indication of an angular position of the input member over multiple turns,
• wherein the rotatable members are configured to rotate simultaneously but at different rates, and
• wherein a set comprising more than one said sensing device is provided for measuring the position of a single said rotatable member, such that if one of the sensing devices in the set develops a fault then another said sensing device in the set is used instead.

A method of providing an indication of an angular position of an input member over multiple turns, the method comprising:

• measuring an angular position of a set of rotatable members configured, in use, to rotate in accordance with rotation of an input member, the rotatable embers being configured to rotate simultaneously but at a different rates, and
• producing an indication of an angular position of the input member over multiple turns sing the angular position measurements received from by a set of sensing devices,
• the method characterized in that the set of rotatable members comprises at least three said rotatable members, and the set of sensing devices comprises at least three said sensing devices configured to measure and output an angular position of a respective one of the at least three rotatable members, and
• wherein each of the rotatable members has any unique ratio of revolution with respect to the other rotatable members, and
• wherein one of the set of rotatable members directly drives all remaining said rotatable members.

A method of providing an indication of an angular position of an input member over multiple turns, the method comprising:

• measuring an angular position of at least two rotatable members configured, in use, to rotate in accordance with rotation of an input member, the rotatable members being configured to rotate simultaneously but at a different rates,
• producing an indication of an angular position of the input member over multiple turns using the angular position measurements,
• taking position measurements of a first one of the rotatable members over a period of time,
• taking position measurements of another of the rotatable members over the period of time,
• comparing the measured position of the other rotatable member with an expected position of the other member, given the measured positions of the first member and a known relationship between rotations of the members, and
• if the measured position of the other rotatable member does not correspond with the expected position then flagging a possible read error state.

A method of providing an indication of an angular position of an input member over multiple turns, the method comprising:

• measuring an angular position of at least two rotatable members configured, in use, to rotate in accordance with rotation of an input member, the rotatable members being configured to rotate simultaneously but at a different rates, and
• producing an indication of an angular position of the input member over multiple turns using the angular position measurements;
• and
• checking for read errors by detecting lack of angular rotation of at least one of the rotatable members.

A method of providing an indication of an angular position of an input member over multiple turns, the method comprising:

• measuring an angular position of at least two rotatable members configured, in use, to rotate in accordance with rotation of an input member, the rotatable members being configured to rotate simultaneously but at a different rates, and
• producing an indication of an angular position of the input member over multiple turns using the angular position measurements;
• wherein the method includes, upon detecting failure of one (or more) of the rotatable members;
• measuring an angular position of non-failed said rotatable member(s), and
• producing an indication of an angular position of the input member over a reduced range of multiple turns using the angular position measurements of the non-failed rotatable member(s).

Apparatus adapted to provide an indication of an angular position of an input member over multiple turns, the apparatus comprising:

• at least two rotatable members configured, in use, to rotate in accordance with rotation of an input member,
• at least one sensing device configured to measure and output an angular position of at least one of the rotatable members, and
• a device configured to use the angular position measurements from the at least one sensing device to produce an indication of an angular position of the input member over multiple turns,
• wherein the rotatable members are configured to rotate simultaneously but at different rates,
• wherein each of the rotatable members has a ratio of revolution with respect to the other rotatable member(s), the rotatable members being arranged so that there is no common factor (other than one) amongst the ratios of revolution, and
• wherein the rotatable members comprise gears each having a different/unique number of teeth.

Apparatus adapted to provide an indication of an angular position of an input member over multiple turns, the apparatus comprising:

• at least two rotatable members configured, in use, to rotate in accordance with rotation of an input member,
• at least one sensing device configured to measure and output an angular position of at least one of the rotatable members, and
• a device configured to use the angular position measurements from the at least one sensing device to produce an indication of an angular position of the input member over multiple turns,
• wherein the rotatable members are configured to rotate simultaneously but at different rates,
• wherein the apparatus includes four said rotatable members.