A sensor system (10) and method for monitoring a powertrain (20) having a drive shaft (1). The sensor system (10) comprises an optical fibre (2) with a strain sensitive element (3). According to one aspect, a connection structure (4) is configured to hold at least a part of the optical fibre (2) with the strain sensitive element (3) at a radial distance (R2-R1) remote from the drive shaft (1) for amplifying the strain (S2) on the strain sensitive element (3) with respect to the strain (51) on the drive shaft (1). According to a further aspect, at least three respective lengths of one or more optical fibres follow parallel, e.g. helical, paths with respect to each other to distinguish different strain forces.

A hoist main shaft torque monitoring device based on angle measurement, constituted primarily by a first base, a second base, a light generating unit, a shutter, and a light sensing element; the light source, a first lens, and a first optical aperture arranged in the light generating unit, as well as a second optical aperture, second lens, and light sensing element on the shutter, forming a light source generation, propagation, and reception pathway; when the elevator main shaft is subjected to a certain torque, a corresponding displacement is produced between the first optical aperture and the second optical aperture, thus measuring the change in amount of light ultimately reaching the second optical aperture so as to measure the twist angle of the rotary shaft and finally calculate the magnitude of the shaft torque. Without damaging the original equipment and foundation, the device measures the torque of the shaft at different rotational speeds. The device can measure stationary torque and torque at different rotational speeds of the shaft, without the electromagnetic field interfering with wireless transmission; the device is easy to use, maintenance costs are low, and it is of interest for widespread popularization.

A hoist main shaft torque monitoring device based on angle measurement, constituted primarily by a first base, a second base, a light generating unit, a shutter, and a light sensing element; the light source, a first lens, and a first optical aperture arranged in the light generating unit, as well as a second optical aperture, second lens, and light sensing element on the shutter, forming a light source generation, propagation, and reception pathway; when the elevator main shaft is subjected to a certain torque, a corresponding displacement is produced between the first optical aperture and the second optical aperture, thus measuring the change in amount of light ultimately reaching the second optical aperture so as to measure the twist angle of the rotary shaft and finally calculate the magnitude of the shaft torque. Without damaging the original equipment and foundation, the device measures the torque of the shaft at different rotational speeds. The device can measure stationary torque and torque at different rotational speeds of the shaft, without the electromagnetic field interfering with wireless transmission; the device is easy to use, maintenance costs are low, and it is of interest for widespread popularization.

The displacement detecting apparatus acquires a quantity of a relative rotational displacement between a scale and a detecting head, based on a change of outputs of the light-receiving elements. The displacement detecting apparatus acquires the quantity of the relative rotational displacement between the scale and the detecting head, by combining a quantity of a rough relative rotational displacement between the scale and the detecting head, which has been acquired from an output of the total of light quantities that are output from each of the light-receiving elements in the detecting head, with a quantity of a fine relative rotational displacement between the scale and the detecting head, which has been acquired from an incremental displacement signal that is output from each of the light-receiving elements in the detecting head.

The displacement detecting apparatus acquires a quantity of a relative rotational displacement between a scale and a detecting head, based on a change of outputs of the light-receiving elements. The displacement detecting apparatus acquires the quantity of the relative rotational displacement between the scale and the detecting head, by combining a quantity of a rough relative rotational displacement between the scale and the detecting head, which has been acquired from an output of the total of light quantities that are output from each of the light-receiving elements in the detecting head, with a quantity of a fine relative rotational displacement between the scale and the detecting head, which has been acquired from an incremental displacement signal that is output from each of the light-receiving elements in the detecting head.

An electric power steering system includes a motor, rotation angle sensors, a determination unit, and a control unit. The determination unit determines whether each rotation angle sensor has a failure by one of determination methods depending on whether a situation is a first situation where one of the rotation angle sensors has a failure or a second situation where the rotation angle sensors have no failures. In the first situation, the control unit continues to control driving of the motor based on a rotation angle of the motor detected by a remaining rotation angle sensor having no failure. Only when determining, in the first situation, whether there is a failure in the remaining rotation angle sensor, the determination unit determines whether there is a failure based on whether a steering torque exhibits a specific behavior assumed to be detected when there is a failure in the remaining rotation angle sensor.

An electric power steering system includes a motor, rotation angle sensors, a determination unit, and a control unit. The determination unit determines whether each rotation angle sensor has a failure by one of determination methods depending on whether a situation is a first situation where one of the rotation angle sensors has a failure or a second situation where the rotation angle sensors have no failures. In the first situation, the control unit continues to control driving of the motor based on a rotation angle of the motor detected by a remaining rotation angle sensor having no failure. Only when determining, in the first situation, whether there is a failure in the remaining rotation angle sensor, the determination unit determines whether there is a failure based on whether a steering torque exhibits a specific behavior assumed to be detected when there is a failure in the remaining rotation angle sensor.

An elastic member of a torque sensor includes spring portions, a first fastening portion, and a second fastening portion. The spring portions are disposed in a radial pattern between the first and second fastening portions to connect the first and second fastening portions together. The spring portions have a dimension smaller in a direction tangential to a circle centered on an rotation axis than in a direction of the radial pattern. The distance between the first fastening portion and the second fastening portion is smaller than the dimension in the direction of the radial pattern. The optical encoders are opposed on, for example, the same diameter on a circumference of a concentric circle centered on a rotation axis of the rotational displacement of the elastic member. For example, averaging output signals from a plurality of optical encoders reduces influence of disturbance, such as cross-axis force.

An elastic member of a torque sensor includes spring portions, a first fastening portion, and a second fastening portion. The spring portions are disposed in a radial pattern between the first and second fastening portions to connect the first and second fastening portions together. The spring portions have a dimension smaller in a direction tangential to a circle centered on an rotation axis than in a direction of the radial pattern. The distance between the first fastening portion and the second fastening portion is smaller than the dimension in the direction of the radial pattern. The optical encoders are opposed on, for example, the same diameter on a circumference of a concentric circle centered on a rotation axis of the rotational displacement of the elastic member. For example, averaging output signals from a plurality of optical encoders reduces influence of disturbance, such as cross-axis force.

A system and method for monitoring bend radius and torque force exerted on a drill string. A sensor system is supported within a pipe section of the drill string and has a light source supported within the pipe section to emit a light beam within the pipe section. An optical sensing device is supported within the pipe section and spaced apart from the light source. The optical sensing device transmits a detection signal indicative of the position of the light beam on a surface of the optical sensing device to a processor that determines the bend radius and torque force exerted on the pipe section.