Absolute digital position encoder with multiple sensors per track
AssigneeBouens, Inc.
InventorMarco Brandestini
Life of this patent
Estimating the term…
Abstract
A method and apparatus to convert absolute angular or linear position to digital information utilizes a ternary coding scheme. The code is arranged along a single track. Sensors placed at essentially equal intervals distinguish three states per position. The sensor outputs are converted from ternary to binary data by combinatorial logic. The sensors may be mechanical contacts, optical detectors, magnetic detectors, or capacitive detectors. Such an encoder may be used as a potentiometer, multiposition switch replacement, shaft encoder, or length measurement device.
Claims47
A method of generating a numerical value representing an absolute position of a first member with respect to a second member where said first and second members are supported for relative movement, comprising the steps of:
- providing on said first member an elongate track having a code extending therealong;
- sensing said code with a plurality of sensors at a plurality of respective locations on said second member, said sensors adjacent said track at spaced locations therealong, said track moving past each said sensor during relative movement of said first and second members;
- and
- for each of N different relative positions of said first and second members, generating a set of digital values, each digital value of said set corresponding to a respective sensor of said plurality of sensors, a code word formed by said set of digital values being unique for each of said N relative positions, wherein N is greater than four times the number of sensors in said plurality of sensors.
An apparatus, comprising:
- a first member having thereon an elongate track with a code extending therealong;
- and
- a second member supported for movement relative to said first member and having thereon a plurality of sensors which are each adjacent said track at spaced locations therealong and which are each configured to sense said code, said sensors each moving along said track in response to relative movement of said first and second members, each of said sensors generating a respective digit of a multi-digit code word representative of an absolute position of said first member relative to said second member, said multi-digit code word having N possible values wherein N is greater than four times the number of said sensors, each of said N values uniquely corresponding to a respective relative position of said first and second members.
A method of generating a multi-digit number representing an absolute position of a first member with respect to a second member where said first and second members are supported for relative movement, comprising the steps of:
- providing on said first member an elongate code track comprised of a plurality of information elements of a code, each of said information elements occupying a respective segment of said track, said segments corresponding to a detectable absolute relative positions of said first and second members;
- sensing said code at a plurality of locations on said second member which are adjacent said track at spaced locations therealong, said track moving past each said location during relative movement of said first and second members;
- and
- for each of said locations, generating a respective digit of said multi-digit number, each said digit having one of a predetermined number of states, said predetermined number being greater than or equal to three, said step of generating responsive to said step of sensing.
An absolute Gray coded position encoder, comprising:
- a first member having a plurality of sensor-detectable elements thereon, said sensor-detectable elements positioned along a common track;
- and
- a second member movably mounted with respect to said first member to define N discrete relative positions of said first and second members, said second member having a set of sensors thereon for detecting said sensor-detectable elements, said sensors spaced apart from one another and positioned in alignment with said track such that said sensor-detectable elements pass adjacent to said sensors, each sensor of said set having an output that corresponds to a respective digit of a code word generated by said encoder, adjacent values of said code word differing in exactly one digit;
- said sensor-detectable elements and said sensors positioned relative to one another so that the value of said code word is unique for each of said N positions, where N is greater than four times the number of sensors in said set.
A 60-position binary absolute position encoder, comprising:
- a first member having a plurality of sensor-detectable elements thereon, said sensor-detectable elements positioned along a common track;
- and
- a second member movably mounted with respect to said first member to define 60 discrete relative positions of said first and second members, said second member having six binary sensors thereon for detecting said sensor-detectable elements, said binary sensors spaced apart from one another and positioned in alignment with said track such that said sensor-detectable elements pass adjacent to said binary sensors, each of said binary sensors having a respective binary output that corresponds to a respective bit of a six-bit code word generated by said encoder, the value of said code word being unique tier each of said 60 relative positions.
A ternary absolute Gray coded position encoder, comprising:
- a first member having a plurality of sensor-detectable elements thereon, said sensor-detectable elements positioned along a common track;
- and
- a second member movably mounted with respect to said first member, said second member having a set of sensors thereon for detecting said sensor-detectable elements, said sensors spaced apart from one another and positioned in alignment with said track such that said sensor-detectable elements pass adjacent to said sensors, each sensor of said set having a respective ternary output that corresponds to a respective ternary digit of a code word generated by said encoder;
- wherein said sensor-detectable elements and said sensors are arranged such that individual values of said code word correspond uniquely to respective relative positions of said first and second members, and such that only one of said ternary digits of said code word can change at-a-time during relative movement of said first and second members.
Dependencies are inferred from the claim text.