Differential capacitive sensor applicable to torque detection

Abstract

The invention discloses a differential capacitive sensor applicable to torque detection. The differential capacitive sensor at least comprises a torque input disc, a torque output disc, a plurality of trapezoidal beams, moving electrodes of a pair of induction capacitors, static electrodes of a pair of induction capacitors, and a substrate, the moving electrodes of the pair of the induction capacitors are respectively located between an outer ring of the torque input disc and an inner ring of the torque output disc and are fixedly connected with the outer ring of the torque input ring to form an integral body, the static electrodes of the pair of the induction capacitors are respectively located at the same sides of the moving electrodes of the corresponding induction capacitors, certain gaps are reserved between the static electrodes and the moving electrodes of the corresponding capacitors, and the moving electrodes of the induction capacitors and the static electrodes of the induction capacitors form a differential-structure vertical electrode type capacitor. According to the differential capacitive sensor, the sensitivity is good, linear errors are small, the anti-interference capability is good, and the linearity of the sensor is greatly improved; and the differential capacitive sensor is realized by employing conventional mechanical machining, the manufacture is simple, and the differential capacitive sensor is applicable to detection of the torque of joint transfer of a series-connection type robot.

Description

technical field [0001] The invention belongs to the field of automatic instrument sensor technology and robot control, and relates to a capacitance sensor, in particular to a differential capacitance sensor suitable for torque detection. Background technique [0002] At present, torque detection sensors are widely used in torque measurement, and can be divided into optical type, photoelectric type, magnetoelectric type, resistance strain type, etc. according to the way of torque signal generation. For example, the essence of the output signal of a magnetoelectric torque sensor is two angular displacement signals with a phase difference. The torque information is obtained after the signals are combined. In the field of robotics, it measures the torque transmitted by the robot joints, and it is not easy to install; the resistance strain torque sensor uses the voltage signal generated by the resistance change as the detection signal to obtain the torque information, and its str...

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Problems solved by technology

For example, the essence of the output signal of a magnetoelectric torque sensor is two angular displacement signals with a phase difference. The torque information is obtained after the signals are combined. In the field of robotics, it measures the torque transmitted by the robot joints, and it is not easy to install; the resistance strain torque sensor uses the voltage signal generated by the resistance change as the detection signal to obtain the torque information, and its structure is complex, requiring additional signal amplification circuits and A / D converters etc. At present, such sensors are more expensive

[0003] At present, for capacitive torque sensors, such as a dynamic torque sensor based on capacitance proposed by Chinese patent CN201344846Y, if the relative position of the shaft and the housing changes, the capacitance signals at both ends of the shaft will have a phase difference. By detecting this capacitance difference, a The relationship between capacitance difference and torque is realized to measure torque. This capacitive torque sensor has a large structure size and can only be used in specific occasions. It is not easy to detect torque in the field of serial robots.

Compared with the traditional parallel electrode capacitive sensor, the sensitivity of the variable pole pitch vertical electrode capacitive sensor based on the capacitive edge effect is less affected by the electrode spacing, but the variable pole pitch vertical electrode capacitive sensor has serious nonlinearity, and Highly affected by noise

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