With the improvement of the degree of automation of various industries, the importance of exercise control is increasingly prominent.In order to effectively drive the motor, it is essential to describe the control input of speed and position.However, there are many technologies that realize this sensing, and each technology has different characteristics and application scenarios.

This article will be more differently rotating sensing technology and discuss the reasons for choosing them.We will then understand some of the latest devices in the market.

Position sensing application

In order to improve accuracy, improve yields and reduce operating costs, many processes that needed manual operation have been automated, which has rapidly increased location sensing applications.In fact, as long as there is a certain form of exercise, there is a need for a sensor to provide location information to the controller.

Industrial 4.0 has made many progress in the field of automation.Robot technology is becoming more and more popular, and the "unmanned" operation is achieved all -weather, and it will not be fatigue or make mistakes -this requires that each motion shaft is equipped with a sensor.The same is true of "collaborative robots" working with humans in traditional factories.

Today, many parts are manufactured by machine -some use CNC (CNC) machine tools, some use laser cutting machines, and some use 3D printers.These machines all have activity components, which require accurate location control to meet the quality goals.After the parts are processed, it is usually transported by automated material handling or conveyor belt, which also requires position sensing function.

In occasions outside the factory, many places also need position control, such as those large medical equipment that can move patients or scanners.In addition, robots can perform surgery now, which also requires very precise control.

In the field of transportation, each application involves exercise.Whether it is traditional transportation such as trains, agricultural machinery, construction machinery, or emerging applications such as autonomous mobile robots (AMR) and thousands of drones in warehousing, position sensing is required.

With all driving methods (ICE), pure electric drive (EV), and hybrid power), all driving cars are developing in the direction of electrification. The mechanical control scheme is being "line -controlled" and "line control steering". Replaced.In order to make these systems operate normally, the location information of the throttle pedal (accelerator) must be transmitted to the electronic control unit (ECU), or the location information of the steering wheel to the steering control system.

As the electronic control expands to almost all aspects of the vehicle operation, the location sensing technology is also widely used in suspension components (for flattening/driving control), power assembly, and electric windows, sunroof, door locks and other aspects.

Position sensing technology comparison

The rotating position sensing mainly uses three technologies -optics, magnetism and inductance technology. Each technology has different working modes, advantages, disadvantages, and application scenarios.

The optical encoder is usually considered the most accurate (although not in all cases). The working principle is to allow the light to pass through the discs with a hole with a hole. When turning around, the light pulse is used to detect the motion.

Figure 1: The main methods of rotating position sensing include optical, magnetic and inductive technology

Generally, this kind of device is used to need high -precision applications, such as precision robots and machine tools such as CNC lathes or laser cutting machines.Although they are highly accurate and are not sensitive to magnetic fields, they are easily affected by vibration and dirt on the disc, which may cause them to fail.

Magnetic encoders are often low -accuracy and are mainly used to apply very sensitive costs.They perform well in the absence of vibration and pollution, but the external magnetic field will have a significant impact on it, which limits their scope of application.

The accuracy of the inductor encoder is better than the magnetic encoder, which can withstand high degrees of vibration and pollution, and is not sensitive to the magnetic field.Other advantages include: good repetitiveness, not sensitive to temperature, small number of devices, small size, and no need for rare earth materials (that is, magnet).

NCS32100 dual inductive position sensor

ONSEMI's NCS32100 dual inductive position sensor achieves excellent non -contact position accuracy through two simple and innovative PCB disks, with an accuracy of +50 cents or a mechanical rotation of 0.0138 degrees.One PCB is fixed on the motor stator (static part), while another single -layer PCB is fixed on a rotor or shaft.Two PCB placed in parallel, separated from 0.1mm to 2.5mm in the middle.NCS32100 is located on the stator PCB.

Thickness (dual) conductive wiring or coil printing on two disks.Article 3 The conductive trace line is called an excitation coil, printed on the stator PCB.NCS32100 sends a 4MHz sine wave to the excitation coil to generate electromagnetic fields around the stator excitation coil.According to the law of Faraday's interaction, the coarse coil of the rotor intersects the electromagnetic field, and the energy is coupled into the rotor coil to form a vortex.

At the same time, the thickness coil of the stator connects up to eight NCS32100 receivers input.When the rotor rotates, the vortex of the rotor will interfere with the stator to receive the coil.The NCS32100 processs these interference through its internal DSP (digital signal processor) proprietary algorithm, thereby measuring the position of the rotor.

Figure 2: Dual inductive technology provides high performance through simple solutions

With a 40mm PCB sensor, the NCS32100 can achieve the position accuracy of ± 50 cents at a speed of 6,000 RPM. In the case of sacrificing some precision, the speed is as high as 45,000 RPM.Based on a larger PCB sensor or accurate the rotor and the stator, it can achieve higher accuracy within +/-10 corners.

This simple solution only needs to use a small amount of electronic devices to ensure small size and low cost.In addition, it is completely sensitive to temperature fluctuations, pollution, and external magnetic fields.

Dual inductive technology integration solution

Ansonami's NCS32100 supports high -precision rotation position sensors designed for industrial applications and environment.It is an absolute position device that can determine the location without exercise.NCS32100 can also calculate the speed at a speed of 45,000 RPM.

At a speed of up to 6,000 RPM, the NCS32100 provides a complete accuracy of ± 50 cents, which is comparable to the performance of many optical encoders.This device also integrates ARM? Cortex? M0+ MCU, which provides high configurable and internal temperature sensors.

The built -in calibration of NCS32100 allows the sensor to achieve self -calibration through a single command. This process only takes two seconds.It does not need to refer to the encoder. As long as the rotor speed is between 100 and 1000 RPM, the program can run at any time.All calibration coefficients are stored in non -easy -to -loss memory (NVM).

Typical optical solutions require a total of three PCB -optical discs, stator PCB, and LED drive PCB, and all functions require about 100 devices.

Figure 3: Dual inductive technology is comparable to optical technology in accuracy, and the complexity and cost are lower than the latter

In contrast, only two PCBs based on the NC32100 solution: rotor is a single -layer PCB that does not contain any device, and the linked PCB contains only 12 devices.

In automotive applications, although cost and reliability are important, safety is even more important, especially in applications such as steering or braking.Ansonmi's car -level absolute position sensor NCV77320 meets the ISO26262 standard and is designed specifically for these key application scenarios.The position accuracy of the NCV77320 is 194.3 corners or a mechanical rotation of 0.0539 degrees (specifically depends on the PCB geometric shape), mainly because it has only 3 receivers input, and the NCS32100 has 8 receivers input, and the NCV77320 does not support the PCB configuration of the coarse fine coil PCB configuration EssenceBoth NCV77320 and NCS32100 can be run as rotary encoder or linear encoder.

The applications of NCV77320 include brake pedal sensors, throttle pedal sensors, motor location sensors, brake system sensors, vehicle horizontal sensors, gearbox gear sensors, throttle position sensors and exhaust gas reinforcement valve sensors.

Like NCS32100, NCV77320 is not sensitive to pollution, temperature changes, and magnetic field interference, and can be used in the automotive environment of -40oc to +150OC.

The NCV77320 can run at a speed of up to 10,800 RPM and communicate with the supporting MCU through the Sent, SPI or analog interface.