Brushless motor control solution for fascia gun

As a popular muscle relaxation device, the brushless motor control scheme of fascia gun is the key to achieve efficient and stable massage function. The following is a detailed introduction to the common fascia gun brushless motor control programme content:

The main control chip: mostly 32-bit microcontroller, such as KYLIN32a, JZ32F031, based on the Cortex-M0 core chip and so on. This kind of chip has strong arithmetic ability and can quickly process complex control instructions to achieve accurate and efficient control of brushless motor. Like KYLIN32a, the main control and BLDC driver can be integrated in one chip, which greatly optimises the cost; JZ32F031 integrates P + N pre-drive, two op-amps and 5V LDO, which reduces the peripheral devices of the microcontroller and improves the overall performance.

Control Mode

Square Wave Control: Control the brushless motor by outputting a PWM square wave signal from the microcontroller. The control logic of this method is relatively simple, which allows the motor to output a larger torque, so that the fascia gun has a powerful massage effect. However, square wave control also has some shortcomings, such as running noise, and the maximum speed of the motor is more difficult to break through 100,000 revolutions.

FOC vector control: some high-end fascia gun will use FOC (magnetic field orientation control) vector control technology, the technology can achieve decoupled control of the motor torque and magnetic chain, so that the motor runs more smoothly and efficiently, significantly reducing vibration and noise, and in the speed range and control accuracy performance is better, which can bring users a more comfortable massage experience. However, the FOC control algorithm is complex and requires higher performance of the main control chip.

Non-inductive control: Many programmes adopt non-inductive control, i.e. removing the Hall sensor of traditional brushless motors, estimating the motor rotor position and speed through algorithms, getting rid of Hall devices and their wires, reducing the number of electronic components, and lowering the failure rate and cost of equipment. In order to achieve accurate non-inductive control, it is necessary for the main control chip to have high-speed ADC acquisition capability and fast data processing capability to accurately collect the motor counterpotential signal to achieve accurate phase change and ensure stable operation of the motor. For example, PY32F003, with a high main frequency of 24MHz, can quickly deal with speed regulation loop (PI) problems, and with its 12-bit ADC (1Msps sampling rate) and DMA-accelerated back-potential acquisition function, it can effectively avoid motor out-of-phase.

Functionality

Multi-speed regulation: It usually supports multi-speed vibration mode adjustment to meet the needs of different users in different scenarios of massage. For example, 3-6 speeds are set for low, medium and high, users can choose according to their muscle tolerance and massage preference. The common speed range is 1000 - 3500RPM, such as 1000RPM, 2000RPM, 2800RPM, 3500RPM and so on. Users can easily switch gears by touching the buttons or ordinary buttons, and some programmes also support long-press buttons to quickly increase or decrease gears.

Timer shutdown: In order to avoid overuse and scientifically control the massage time, the fascia gun has a timer shutdown function, and the general timer length is about 10 minutes. After arriving at the set time, the motor automatically stops running and the device enters standby mode to prevent muscle damage caused by prolonged massage.

Pressure sensing protection: Some advanced programmes are equipped with pressure sensors, which automatically adjust the motor output power or issue an alarm to remind the user when the pressure is detected to be too large, preventing the user from exerting improper force on the body, and enhancing the safety of use.

Light indicators: LED indicators are provided for prompting the status of the device, such as the power display, through different colours or the number of lights intuitively present the remaining power, which is convenient for the user to understand the power status of the device in time and recharge; there are also mode indicators, which can display the currently selected massage gear or working mode, enhancing the interactive experience of user operation. Part of the programme also supports power, mode walking light cool tips function, increase the diversity and attractiveness of product design.

Over-current, over-voltage, blocking protection: with a perfect protection mechanism, when the motor over-current, over-voltage, blocking and other abnormalities, the control board can quickly cut off the circuit or take appropriate measures to protect, avoid damage to the motor and the control board, prolong the service life of the equipment to ensure the safety and stability of the use process.

Power management

Battery selection: generally use rechargeable lithium batteries, such as common 2200MAH capacity battery, to ensure that the equipment endurance to meet the needs of users for multiple use. Different programmes can be adapted to different specifications and number of lithium batteries, such as single lithium batteries or multiple lithium batteries in series to form a battery pack, such as 6 strings of 18650 lithium battery pack (22.2V / 1600mAH).

Charge management: equipped with the appropriate charging circuit and management chip, support for traditional charging methods, while part of the programme to introduce fast charging technology, significantly reducing the charging time, such as from the original traditional charging takes more than 3.5 hours, the use of fast-charging technology can be fully charged in just half an hour, to enhance the convenience of the user. Moreover, it has over-charging and over-discharging protection functions to prevent the battery from being damaged due to over-charging or over-discharging, and prolong the service life of the battery.

Motor Driving Circuit: The BLDC motor driving circuit is specially designed to control the speed and steering of the brushless motor. The circuit works with the main control chip to convert the control signals from the main control chip into appropriate voltage and current to drive the brushless motor according to the set mode and achieve stable and efficient massage action output. The circuit design needs to take into account the power and current requirements of the motor, as well as electromagnetic compatibility and other factors, in order to ensure the stability and reliability of the motor operation