Position Acquisition for Long Primary Linear Drives with Passive Vehicles

In order to implement magnetic guidance in a long primary linear motor, the measurement of the airgap and yaw angle is required. Usual gap sensors deliver the signal and require power supply in the moving part. In this case, a power and data transmission system is necessary between the mover and the stationary controller. In addition to the magnetic guidance, a new type of capacitive sensor system was developed to eliminate the power and data transmission for the measurement of the air gap widths and yaw angle. Calculation and experimental results show the feasibility of the proposed system.

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“…It becomes even more complex when the track is non-straight as e.g. in curvilinear conveyor systems [10].…”

Section: Introductionmentioning

confidence: 99%

Magnetic guiding and capacitive sensing for a passive vehicle of a long-primary linear motor

Khong

Leidhold

Mutschler

2010

Proceedings of 14th International Power Electronics and Motion Control Conference EPE-PEMC 2010

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“…The developments of precise measurement and positioning devices have been applied to manufacture processing and testing equipment in the fields of electronic and semiconductor industries. In these devices, linear scale encoders are widely used to detect angular and/or translational positions of the moving part in high-precision machines and robots as the most common position sensors [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ]. However, the frequency response of the conventional encoders is limited; thus, they cannot be used in the case of high-speed motions.…”

Section: Introductionmentioning

confidence: 99%

“…This problem can be mitigated with a high-resolution linear scale equipped with a high-speed front-end readout and signal processing chip, which can output harmonic signals to obtain greater accuracy and higher resolution. Among different scales, it is known that magneto-resistance (MR) scales, as compared to other scales, especially optical scales [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ], have the advantages of low cost, high speed, accuracy and adequate precision. In comparison of the accuracies offered by MR and optical scales, the optical scale using the reflection principle could achieve a resolution higher than the MR scale, but the MR scale requires much lower costs for components and manufacturing.…”

Section: Introductionmentioning

confidence: 99%

“…The electrodes are designed in a particular way, as shown in Figure 2 b, to generate sinusoids and co-sinusoids at outputs A± and B± that are proportional to the resistance variations through a Wheatstone bridge, as shown in Figure 2 a. The resulted sinusoids and co-sinusoids in Figure 2 b can next be deciphered by a succeeding readout chip to acquire the moving distance of the reader [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. In fact, in addition to the design of MR electrodes, another critical technology involved in magnetic scales is the readout IC, which needs to be capable of converting the resistance variations of MR electrodes to digits in a high signal-to-noise ratio and then deciphering the resulting digital harmonics to reader positions.…”

Section: Introductionmentioning

confidence: 99%

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The Front-End Readout as an Encoder IC for Magneto-Resistive Linear Scale Sensors

Tran

Chao

Chien

2016

Sensors

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This study proposes a front-end readout circuit as an encoder chip for magneto-resistance (MR) linear scales. A typical MR sensor consists of two major parts: one is its base structure, also called the magnetic scale, which is embedded with multiple grid MR electrodes, while another is an “MR reader” stage with magnets inside and moving on the rails of the base. As the stage is in motion, the magnetic interaction between the moving stage and the base causes the variation of the magneto-resistances of the grid electrodes. In this study, a front-end readout IC chip is successfully designed and realized to acquire temporally-varying resistances in electrical signals as the stage is in motions. The acquired signals are in fact sinusoids and co-sinusoids, which are further deciphered by the front-end readout circuit via newly-designed programmable gain amplifiers (PGAs) and analog-to-digital converters (ADCs). The PGA is particularly designed to amplify the signals up to full dynamic ranges and up to 1 MHz. A 12-bit successive approximation register (SAR) ADC for analog-to-digital conversion is designed with linearity performance of ±1 in the least significant bit (LSB) over the input range of 0.5–2.5 V from peak to peak. The chip was fabricated by the Taiwan Semiconductor Manufacturing Company (TSMC) 0.35-micron complementary metal oxide semiconductor (CMOS) technology for verification with a chip size of 6.61 mm2, while the power consumption is 56 mW from a 5-V power supply. The measured integral non-linearity (INL) is −0.79–0.95 LSB while the differential non-linearity (DNL) is −0.68–0.72 LSB. The effective number of bits (ENOB) of the designed ADC is validated as 10.86 for converting the input analog signal to digital counterparts. Experimental validation was conducted. A digital decoder is orchestrated to decipher the harmonic outputs from the ADC via interpolation to the position of the moving stage. It was found that the displacement measurement error is within ±15 µm for a measuring range of 10 mm.

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“…With the increase in the application of linear motors, the position estimation method has captured a lot of attention. In conventional methods, linear encoders are used as the most common position sensors [ 1 , 2 , 3 ]. A linear encoder gives precise position information, but for a long track application, the use of linear encoders is very expensive and difficult to implement due to the size of the encoder.…”

Section: Introductionmentioning

confidence: 99%

A New Approach to Detect Mover Position in Linear Motors Using Magnetic Sensors

Paul

Chang

2015

Sensors

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A new method to detect the mover position of a linear motor is proposed in this paper. This method employs a simple cheap Hall Effect sensor-based magnetic sensor unit to detect the mover position of the linear motor. With the movement of the linear motor, Hall Effect sensor modules electrically separated 120° along with the idea of three phase balanced condition (va + vb + vc = 0) are used to produce three phase signals. The amplitude of the sensor output voltage signals are adjusted to unit amplitude to minimize the amplitude errors. With the unit amplitude signals three to two phase transformation is done to reduce the three multiples of harmonic components. The final output thus obtained is converted to position data by the use of arctangent function. The measurement accuracy of the new method is analyzed by experiments and compared with the conventional two phase method. Using the same number of sensor modules as the conventional two phase method, the proposed method gives more accurate position information compared to the conventional system where sensors are separated by 90° electrical angles.

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Position Acquisition for Long Primary Linear Drives with Passive Vehicles

Cited by 7 publications

References 1 publication

Magnetic guiding and capacitive sensing for a passive vehicle of a long-primary linear motor

Magnetic guiding and capacitive sensing for a passive vehicle of a long-primary linear motor

The Front-End Readout as an Encoder IC for Magneto-Resistive Linear Scale Sensors

A New Approach to Detect Mover Position in Linear Motors Using Magnetic Sensors

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