A Novel Method for Determining Angular Speed and Acceleration Using Sin-Cos Encoders

Precise motor control requires high accuracy of the rotor position through the incremental encoder. The speed and accuracy of the acquisition equipment (microcontroller) play an important element in terms of cost and efficiency. In this paper, the author presents alternative methods for speed acquisition from an incremental encoder. In the first stage of research, the main performances of the STM32 microcontroller, connected with an incremental encoder, will be analyzed and compared with two different acquisition systems, i.e., ELVIS II and a Unidrive M701 power inverter. Using the LabVIEW graphical programming language, a user-friendly, convenient, and flexible human–machine interface is designed. Due to the advantages provided by the STM32 microcontroller in terms of processing power, cost, and programming interface, the obtained results are accurate and consistent. Through experimental testing and analysis, the speed acquisition is stable for both developed software algorithms used for ELVIS II and STM32 platforms. It is the aim of the paper to propose a useful speed acquisition tool in low-cost, high-accuracy prototyping applications.

“…The authors of [ 15 ] proposed an angular speed estimation for different calculation frequencies. The encoder’s digital signal is sampled at 1 MHz.…”

Section: Frequency and Time-period Measurementmentioning

confidence: 99%

Incremental Encoder Speed Acquisition Using an STM32 Microcontroller and NI ELVIS

Pop

2022

“…In this case the observer includes an automated routine to compensate the misalignment of Hall sensors based on computing the time between Hall-Effect transitions and compare this value with the ideal values stored in a lookup table. Similarly, Ortiz et al [ 10 ] simulated a method for high resolution position estimation of a BLDC motor based on the measurement of the pulses obtained from three Hall Effect sensors providing 12 rising and falling edges or 12 pulses per revolution while Alcázar et al [ 11 ] avoids possible asymmetries originated by the Hall Effect sensor by using only the rising edges of the output signal.…”

Section: Introductionmentioning

confidence: 99%

Improving the Angular Velocity Measured with a Low-Cost Magnetic Rotary Encoder Attached to a Brushed DC Motor by Compensating Magnet and Hall-Effect Sensor Misalignments

Palacín

Martínez

2021

This paper proposes a method to improve the angular velocity measured by a low-cost magnetic rotary encoder attached to a brushed direct current (DC) motor. The low-cost magnetic rotary encoder used in brushed DC motors use to have a small magnetic ring attached to the rotational axis and one or more fixed Hall-effect sensors next to the magnet. Then, the Hall-effect sensors provide digital pulses with a duration and frequency proportional to the angular rotational velocity of the shaft of the encoder. The drawback of this mass produced rotary encoder is that any structural misalignment between the rotating magnetic field and the Hall-effect sensors produces asymmetric pulses that reduces the precision of the estimation of the angular velocity. The hypothesis of this paper is that the information provided by this low-cost magnetic rotary encoder can be processed and improved in order to obtain an accurate and precise estimation of the angular rotational velocity. The methodology proposed has been validated in four compact motorizations obtaining a reduction in the ripple of the estimation of the angular rotational velocity of: 4.93%, 59.43%, 76.49%, and 86.75%. This improvement has the advantage that it does not add time delays and does not increases the overall cost of the rotary encoder. These results showed the real dimension of this structural misalignment problem and the great improvement in precision that can be achieved.

“…A new method to obtain the wheel speed by using Sin-Cos encoders is presented in [ 2 ]. The methodology is based on the use of Savitzky–Golay filters to optimally determine the coefficients of the polynomials that best fit the measured signals and their time derivatives.…”

mentioning

confidence: 99%

Sensors for Road Vehicles of the Future

Jiménez

2022