Position sensor, position measuring device and method for the operation thereof

Abstract

A position signal generator for an electronic position measuring device is disclosed. In an embodiment, the position signal generator includes a signal generation device for generating a periodic magnetic signal, and an electric power supply device for supplying the signal generation device with electric energy. The position of the position signal generator is determined via the position measuring device.

1 . A position measuring device for detecting a position of a position signal generator that can be moved along a measuring path, wherein the position measuring device comprises at least a first conductor loop that is arranged along the measuring path for detecting a magnetic signal, generated by the position signal generator, wherein the first conductor loop is embodied such that a magnetic coupling between a signal generation device of the position signal generator and the first conductor loop changes in dependence on the position of the position signal generator, and wherein it comprises an evaluation unit for detecting the position in dependence on a first signal, generated by the magnetic signal in the first conductor loop, wherein said position measuring device comprises at least one induction coil and is configured to generate, by means of said at least one induction coil, an induction field for supplying said position signal generator with energy. 
     
     
         2 . The position measuring device according to  claim 1 , wherein furthermore a second conductor loop, arranged at least sectionally along the measuring path, is provided for detecting the magnetic signal generated by the position signal generator, wherein the evaluation unit is designed for detecting the position in dependence on the first signal and a second signal generated by the magnetic signal in the second conductor loop, and wherein preferably at least one segment of the first conductor loop is essentially approximately sine-shaped, relative to a reference position of the measuring path, and at least one segment of the second conductor loop is essentially approximately cosine-shaped, relative to the reference position of the measuring path. 
     
     
         3 . The position measuring device according to  claim 1 , wherein at least one conductor loop is embodied such that the size of a differential surface element of the at least one conductor loop changes along a coordinate axis of the measuring path in accordance with a specifiable function. 
     
     
         4 . The position measuring device according to  claim 3 , wherein at least three conductor loops are provided, wherein a function assigned to the first conductor loop is a sine function, wherein a function assigned to the second conductor loop is a cosine function, and wherein a function assigned to the third conductor loop is a constant. 
     
     
         5 . The position measuring device according to  claim 1 , wherein said at least one induction coil is arranged around said at least first conductor loop. 
     
     
         6 . The position measuring device according to  claim 1 , wherein said at least one induction coil is operated with a frequency of approximately 1 MHz or more. 
     
     
         7 . The position measuring device according to  claim 1 , wherein said at least one induction coil is operated within a frequency range between approximately 1 MHz to approximately 4 MHz. 
     
     
         8 . The position measuring device according to  claim 1 , wherein said magnetic signal is a periodic magnetic signal. 
     
     
         9 . The position measuring device according to  claim 1 , wherein said magnetic signal has a frequency component in the range of approximately one kilohertz to approximately 200 kilohertz. 
     
     
         10 . The position measuring device according to  claim 1 , wherein said magnetic signal has a frequency component in the range of approximately 10 kilohertz to approximately 20 kilohertz. 
     
     
         11 . The position measuring device according to  claim 1 , wherein a distance between the position signal generator and a plane comprising said first conductor loop ranges between about 0.1 mm and 10 mm. 
     
     
         12 . The position measuring device according to  claim 1 , wherein the position signal generator is arranged sliding directly on a surface of the first conductor loop or a support element carrying said first conductor loop or a sliding layer provided on said first conductor loop. 
     
     
         13 . The position measuring device according to  claim 1 , wherein said induction coil comprises a field balancing topology that causes a reduction of magnetic fields around the induction coil. 
     
     
         14 . The position measuring device according to  claim 1 , wherein at least one further conductor loop is provided which comprises a sine-shaped geometry along a coordinate axis of the measuring path, said at least one further conductor loop having a longer wavelength than said first conductor loop. 
     
     
         15 . The position measuring device according to  claim 2 , wherein said evaluation unit comprises a phase shifter, an adder, and a phase comparator, wherein said evaluation unit is configured to, by means of the phase shifter, apply a phase shift of 90° to said second signal to obtain a phase-displaced signal, to add, by means of the adder, the first signal to the phase-displaced signal to obtain a sum signal, to determine, by means of the phase comparator, a phase difference between a reference signal and the sum signal, and to determine the position of the position signal generator based on said phase difference between said reference signal and said sum signal. 
     
     
         16 . The position measuring device according to  claim 15 , wherein said position measuring device is configured to convert the sum signal to a first digital signal, and to convert the reference signal to a second digital signal, wherein at least one of comparators or Schmitt triggers are used, wherein said position measuring device is configured to perform a comparison between the phases of the first and the second digital signal by means of a time measurement. 
     
     
         17 . The position measuring device according to  claim 1 , wherein said position measuring device is configured to at least temporarily provide said at least first conductor loop with a periodic signal by means of the evaluation unit or a separate signal generator to effect a reliable startup of an oscillator of said position signal generator, wherein said periodic signal essentially has the same frequency as said oscillator of the position signal generator. 
     
     
         18 . The position measuring device according to  claim 1 , wherein said measuring path is curved, having a two-dimensional or three-dimensional course. 
     
     
         19 . A method for operating a position measuring device for detecting a position of a position signal generator, which can be moved along a measuring path, wherein the position measuring device is provided with at least a first conductor loop, arranged along the measuring path for detecting a magnetic signal that is generated by the position signal generator, wherein the first conductor loop is embodied such that a magnetic coupling between a signal generation device of the position signal generator and the first conductor loop changes in dependence on the position of the position signal generator, and wherein an evaluation unit detects the position in dependence of a first signal generated in the first conductor loop by the magnetic signal, wherein said position measuring device comprises at least one induction coil and generates, by means of said at least one induction coil, an induction field for supplying said position signal generator with energy. 
     
     
         20 . The method according to  claim 19 , wherein furthermore a second conductor loop which is arranged at least sectionally along the measuring path is provided for detecting the magnetic signal, generated by the position signal generator, wherein the evaluation unit detects the position in dependence on the first signal and a second signal, generated by the magnetic signal in the second conductor loop, wherein preferably at least one segment of the first conductor loop is essentially approximately sine-shaped, relative to a reference position of the measuring path, and at least one segment of the second conductor loop is essentially cosine-shaped, relative to the reference position of the measuring path. 
     
     
         21 . The method according to  claim 19 , wherein at least three conductor loops are provided, wherein a function assigned to the first conductor loop is a sine function, wherein a function assigned to the second conductor loop is a cosine function, and wherein a function assigned to the third conductor loop is a constant, and wherein the evaluation unit detects the position in dependence on the first signal and a second signal, generated by the magnetic signal in the second conductor loop, as well as a third signal generated by the magnetic signal in the third conductor loop. 
     
     
         22 . The method according to  claim 20 , wherein the second signal is phase displaced by 90 degrees to obtain a phase-displaced second signal, wherein the first signal is added to the phase-displaced second signal to obtain a sum signal, and wherein a phase comparison is realized between the sum signal and the third signal to detect the position. 
     
     
         23 . The method according to  claim 22 , wherein the phase comparison includes the following steps: converting the sum signal to a first digital signal; converting the third signal to a second digital signal; comparing the phases of the first and the second digital signal with the aid of a time measurement, so as to determine the position.