CS245385B1 - Non-contact angle sensor - Google Patents

Abstract

The contactless angle sensor is designed to sense the position of control levers and flaps. The contactless sensor has polarizing filters placed between the light source (1) and the optoelectronic element (4). (2, 3) of which one is fixed and the other is connected to a rotatably mounted element. The contactless sensor can be used, for example, in electronically controlled combustion engines.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contactless angle sensor of a rotatably mounted component, particularly suitable for indicating the position of the operating levers.

Known angular position sensors are designed as rotary poteneiometers with a mass resistance path and a graphite movable contact. The mechanical contact between the contact and the resistance path of these sensors, however, has a negative effect on their service life, because the abrasion of the resistance layer changes not only its total resistance but also the sensor's own characteristics, ie the output electrical quantity dependence on the angle of rotation.

[0008] The aforementioned drawbacks are overcome by the contactless angle sensor of the present invention having a fixed polarizing filter and a movable polarizing filter coupled to the rotatable member between the light source and the optoelectric member. In order to achieve a linearized characteristic of the electrical quantity at the sensor output, said system comprising a light source, a movable polarizing filter, a fixed polarizing filter and an optoelectric element may be doubled, the movable polarizing filter being common, planes of fixed polarizing filters and each optoelectronic.

In order to ensure the accuracy of the sensed variable in the case of temperature fluctuations, said embodiments may be supplemented by a reference light source, two reference polarization filters having the same polarization plane, a reference optoelectric element and a light source supply circuit. with light source power circuit input.

Said non-contact sensor characterized by long-term stability of the parameters and the overall service life is shown in the attached schematic sketches, where Fig. 1 represents the basic version of the sensor, Fig. 3 the basic version with temperature compensation, Fig. 2 the sensor with linearized output characteristic.

The basic embodiment of the contactless angle sensor according to FIG. 1 consists of a light source 2 which passes through a movable polarizing filter 2 connected to a part whose angle of rotation is sensed (not shown) and a fixed polarizer 2 to an optoelectronic member 2 converting transmitted light to output electrical quantity, the value of which is proportional to its intensity. The light intensity is a trigonometric function of the angle between the polarization planes of the two polarizing filters, therefore, if a linear characteristic is needed, it is advisable to use a sensor with linearized characteristic according to Fig. 2. 2, fixed polarization filters 3, whose polarization planes are perpendicular to each other, and optoelectronic elements 2 · Outputs of optoelectronic elements i are connected to inputs of differential amplifier 9. By suitable selection of elements of differential amplifier it is possible to achieve deviation from linear characteristic + 1.6% amplitude the difference between the maximum and minimum values of the output signal). As a differential amplifier, an opamp can be advantageously used.

Another possible variant is a contactless sensor with temperature compensation (Fig. 3), again consisting of the basic design according to Fig. 1 extended by reference light sources 5, fixed reference polarizing filters 2 »reference optoelectronic element T and power supply circuit 2 of sources. If the sensitivity of the reference optoelectronic element 7 or the efficiency of the reference light source 2 changes as a result of temperature, the output of the light source supply circuit 8 changes against the influences causing it, so that the output of the reference optoelectronic element 11 maintains a constant value . Since the light source 2 and the optoelectronic element 2 have a temperature dependence identical to the reference light source 2 and the reference optoelectronic element and the light source 2 and the light reference source 2 are supplied from the same supply circuit 1, the temperature dependence of the actual angle sensor .

Said non-contact sensor can be advantageously used, for example, in electronic engine control systems as an element for sensing the position of a carburetor throttle valve, or a thrust for controlling the mixing ratio.

Claims (3)

A contactless angle sensor of a rotatably mounted component, particularly suitable for indicating the position of the control levers, characterized in that a fixed polarizing filter (3) and a movable polarizing filter (2) are connected between the light source (1) and the optoelectronic member (4) with rotatable structural element. The contactless angle sensor according to claim 1, characterized in that the system comprising the light source (1), the movable polarizing filter (2), the fixed polarizing filter (3) and the optoelectronic member (4) is doubled, the movable polarizing filter (2). ) is common, the polarization planes of the fixed polarization filters (3) are perpendicular to each other and the optoelectronic elements (4) are connected to the differential amplifier (9). 3. The contactless angle sensor according to claim 1, characterized in that the light source (1) is assigned a reference light source (5), two reference filters (6) with the same polarization plane, a reference optoelectronic element (7) and a power circuit (8). ) of light sources (1, 5), wherein the reference polarizing filters (6) are between the reference source (5) and the optoelectronic member (7) connected to the input of the supply circuit (8) of the light sources (1, 5).