Parking safety control method of brushless hub motor based on reverse torque

Abstract

The present invention relates to a brushless hub motor parking safety control method based on reverse torque. The present invention adopts a brushless hub motor parking safety control method based on reverse torque, comprising the following steps: S1. Sending a parking signal to a controller; S2. The controller records the parking start speed V 始 , calculate the estimated longest braking time T 最长 and the estimated longest braking distance S 最长 ; S3. Adjust the output torque of the motor n times to make the output torque of the motor approach 0; if the actual speed of the motor is greater than the set value V1 after reducing the output torque n times, the controller sends a control signal to make the motor provide a reverse torque F1, thereby achieving deceleration, and finally making the actual speed of the motor lower than the set value V1. The present invention has the advantage of enabling equipment with a brushless hub motor to park safely without the need to set an electromagnetic brake.

Description

Technical Field

[0001] The invention relates to a brushless hub motor parking safety control method based on reverse torque. Background Art

[0002] Slow-speed mobility tools such as scooters and wheelchairs with brushless hub motors are usually equipped with brakes, which are electromagnetic brakes or mechanical brakes. Whether electromagnetic brakes or mechanical brakes are installed, the overall weight of the equipment with brushless hub motors will increase, which is not conducive to lightweighting.

[0003] At the same time, when a scooter / wheelchair using electromagnetic brakes is in normal driving, the electromagnetic brakes are always powered on, which will cause the scooter / wheelchair to consume a lot of energy during driving, requiring the use of a larger battery, or limiting its driving range; while a scooter / wheelchair using mechanical brakes requires manual braking to stop. Summary of the invention

[0004] The object of the present invention is to provide a brushless hub motor parking safety control method based on reverse torque which can ensure parking safety and does not require the installation of mechanical brakes or electromagnetic brakes.

[0005] To achieve the above object, the present invention adopts a brushless hub motor parking safety control method based on reverse torque, comprising the following steps:

[0006] S1. Send a parking signal to the controller;

[0007] S2. The controller records the parking start speed V 始 , according to the parking starting speed V 始 Calculate the estimated maximum braking time T 最长 and the estimated longest braking distance S 最长 ;

[0008] S3. The controller sends a control signal to the motor to adjust the output torque of the motor n times so that the output torque of the motor approaches 0;

[0009] If the actual speed of the motor is greater than the set value V1 after reducing the output torque n times, the controller sends a control signal to make the motor provide a reverse torque F1, thereby achieving deceleration, and finally making the actual speed of the motor lower than the set value V1;

[0010] In step S3, when the actual braking time T 实 Greater than T 最长 Or actual braking distance S 实 Greater than S 最长 When the motor is in a state of braking, the controller sends a signal to increase the reverse torque F2 generated by the motor to force braking, F2>F1.

[0011] In step S1, the movement of the scooter throttle lever or the wheelchair controller joystick can be canceled by releasing the throttle lever or the wheelchair controller joystick to achieve the sending of the parking signal. In step S3, the output torque of the motor is reduced multiple times to achieve slow descent, making the deceleration smoother so that the motor speed reaches the parking setting value V1 to improve user comfort. Among them, the setting value V1 can be a lower speed or 0; when the setting value V1 is a lower speed close to 0, parking is achieved by self-weight friction. When the actual braking time and braking distance exceed the estimated time and estimated distance, the motor is forced to brake by generating a reverse torque to change the slow braking into an emergency braking to achieve braking. Among them, n is a specific value set according to the equipment model.

[0012] In the scheme of the present invention, electromagnetic brakes and mechanical brakes are not used to achieve speed reduction and parking, and there is no need to set corresponding brakes on the equipment with the brushless hub motor of the present invention, which can make the equipment as a whole lighter, with fewer assembly steps and more convenient storage and transportation management of parts.

[0013] Preferably, in step S2, the estimated maximum braking time T 最长 =T 基础 +V 始 *T 最快 , T 基础 Set the duration as the basis, T 最快 It is the fastest time for the device using this motor to brake to 0 output speed when the speed gear is the lowest.

[0014] The basic setting time can be based on the time taken for various types of equipment equipped with the motor to brake to a working speed of 0 when the equipment is in the lowest speed gear on a horizontal road.

[0015] Preferably, in step S2, the estimated longest braking distance S 最长 =S 基础 +V 始 *S1,S 基础 The braking distance is set as the basis, and S1 is the additional braking distance for every 1 km / h increase in the motor speed of the device using this motor.

[0016] By determining the shortest braking distance, it is possible to avoid braking too quickly, to avoid the device with the motor having a large inertia during the braking process, and to reduce the back-pushing feeling and the risk of tipping forward during use. At the same time, by setting the longest braking distance, it is possible to prevent the reverse torque from being ineffective over a long distance, resulting in the device with the motor of the present invention having a too long braking distance (such as parking on a downhill section), so that the device with the motor of the present invention meets the requirements of the corresponding specifications.

[0017] Preferably, in step S3, the output torque of the motor is reduced in equal proportion each time.

[0018] The output torque of the motor is reduced in the same proportion each time, which can achieve linear speed reduction and make the speed reduction smoother.

[0019] Preferably, in step S3, 10≤n≤100.

[0020] The output torque is reduced at least 10 times to ensure linear deceleration; by making n less than 100, it is possible to avoid the motor output torque reduction taking too long and to avoid overly complex program settings. At the same time, different motors have different output torques, and motors with large output torques should require longer braking time to prevent the output torque from decreasing too quickly and braking too hastily.

[0021] Preferably, in step S3, as the time of the reverse torque F provided by the motor increases, the reverse torque F1 provided by the motor gradually increases. 1后 =F 1后 +(-dir*F 定 ), F 定 is a fixed torque value. When the motor rotates in the forward direction, dir is 1, otherwise dir is -1. 定 The specific value is set according to the equipment model; the corresponding model of equipment is braked before leaving the factory to obtain the specific value of the corresponding model.

[0022] As a preferred embodiment, in step S2, the stop start time T is recorded. 始 .

[0023] As a preferred method, F2=-Kp*Pos+SumI, SumI 后 =SumI 前 +(-Spd*ki); where Kp is the moving distance adjustment parameter, Pos is the moving distance, which is positive when moving forward and negative when moving backward; SumI is the speed adjustment integral value, Spd is the rotation speed, which is positive when moving forward and negative when moving backward, and ki is the adjustment ratio; if Spd*SumI>0, SumI is cleared and SumI is recalculated. 后 .

[0024] The present invention has the advantages of enabling equipment with a brushless hub motor to be safely parked without the need to provide an electromagnetic brake or a mechanical brake. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention is a method control flow chart. DETAILED DESCRIPTION

[0026] The present invention will be further described below based on the accompanying drawings and specific embodiments.

[0027] Depend on Figure 1As shown, this embodiment discloses a brushless hub motor parking safety control method based on reverse torque. This embodiment is used for a wheelchair and includes the following steps S1, S2 and S3.

[0028] S1. Reset the joystick of the wheelchair controller to send a parking signal to the controller.

[0029] S2. Record the initial speed V 始 and the dwell start time T 始 , according to the parking starting speed V 始 and the dwell start time T 始 Calculate the estimated maximum braking time T 最长 and the estimated longest braking distance S 最长 ; Estimated maximum braking time T 最长 =T 基础 +V 始 *T 最快 , T 基础 Set the duration as the basis, T 最快 The fastest time it takes for a wheelchair using this motor to brake to 0 when the motor output speed is at the lowest speed gear; the estimated longest braking distance S 最长 =S 基础 +V 始 *S1,S 基础 The braking distance is set as the basis, and S1 is the additional braking distance for every additional 1 km / h of the motor speed of the wheelchair using this motor.

[0030] Among them, T of this embodiment 基础 is 600 milliseconds, T 最快 is 220 milliseconds, S 基础 is 0.6 m, S1 is 0.1 m.

[0031] S3. Reduce the output torque of the motor in proportion to n times, so that the working speed of the motor gradually decreases; 10≤n≤100;

[0032] If the motor speed is greater than the set value V1 after reducing the output torque n times, the motor will provide a reverse torque to achieve deceleration and eventually stop the wheel from rotating. As the time of the reverse torque F1 provided by the motor increases, the reverse torque F1 provided by the motor gradually increases, and F 1后 =F 1后 +(-dir*F 定 ), F 1定 is a fixed torque value. When the motor rotates in the forward direction, dir is 1, otherwise dir is -1. The set value V1 in this embodiment is 1 kilometer per hour.

[0033] In step S3, when the actual braking time T 实Greater than T 最长 Or actual braking distance S 实 Greater than S 最长 When the motor generates reverse torque F2, it brakes forcefully.

[0034] Among them, by detecting the magnitude of the current generated by the motor rotor cutting the magnetic field when the wheelchair wheels rotate, it is evaluated whether the wheelchair of this embodiment is on a ramp. Compare the magnitude relationship between the current I of the two motors of the wheelchair and the minimum current I_limit when the motors are working. If I>I_limit, it means that the wheelchair is on a ramp. The larger the current I, the greater the external force on the wheelchair when it is parked on the slope. It is further deduced that the larger the slope, the greater the reverse torque of the motor.

[0035] At the same time, compare the relationship between the braking torque output value PWM of the wheelchair motor on the slope and Pwm_limit. Pwm_limit is the minimum braking torque output value of the motor when judging whether the wheelchair is on a slope; when PWM<-pwm_limit, it is judged that the wheelchair is on a downhill slope, and when PWM>pwm_limit, it is judged that the scooter / wheelchair is on an uphill slope, thereby determining whether the motor rotation direction is forward or reverse, thereby determining the direction of the motor's reverse torque.

[0036] F2=-Kp*Pos+SumI,SumI 后 =SumI 前 +(-Spd*ki); where Kp is the moving distance adjustment parameter, Pos is the moving distance, which is positive when moving forward and negative when moving backward; SumI is the speed adjustment integral value, Spd is the rotation speed, which is positive when moving forward and negative when moving backward, and ki is the adjustment ratio; if Spd*SumI>0, SumI is cleared and SumI is recalculated. 后。

Claims

1. A brushless hub motor parking safety control method based on reverse torque, characterized in that The following steps are involved: S1. Send a parking signal to the controller; S2. The controller records the parking start speed V 始 , according to the parking starting speed V 始 Calculate the estimated maximum braking time T 最长 and the estimated longest braking distance S 最长； S3. The controller sends a control signal to the motor to adjust the output torque of the motor n times so that the output torque of the motor approaches 0; If the actual speed of the motor is greater than the set value V1 after reducing the output torque n times, the controller sends a control signal to make the motor provide a reverse torque F1, thereby achieving deceleration, and finally making the actual speed of the motor lower than the set value V1; In step S3, when the actual braking time T 实 Greater than T 最长 Or actual braking distance S 实 Greater than S 最长 When the load is stopped, the controller sends a signal to increase the reverse torque F2 generated by the motor to force braking, F2>F1.

2. The method for safely controlling the parking of a brushless hub motor based on reverse torque according to claim 1, characterized in that: In step S2, the estimated maximum braking time T 最长 =T 基础 +V 始 *T 最快 , T 基础 Set the duration as the basis, T 最快 It is the fastest time for the device using this motor to brake to the motor output speed of 0 when the speed gear is the lowest.

3. The parking safety control method of the brushless hub motor based on reverse torque according to claim 1 is characterized in that: In step S2, the estimated longest braking distance S 最长 =S 基础 +V 始 *S1,S 基础 The braking distance is set as the basis, and S1 is the additional braking distance for every 1 km / h increase in the motor speed of the device using this motor.

4. The parking safety control method of a brushless hub motor based on reverse torque according to claim 1, characterized in that: In step S3, the output torque of the motor is reduced proportionally each time.

5. The parking safety control method of a brushless hub motor based on reverse torque according to claim 1 or 4, characterized in that: In step S3, 10≤n≤100.

6. The parking safety control method of a brushless hub motor based on reverse torque according to claim 1, characterized in that: In step S3, as the time of the reverse torque F provided by the motor increases, the reverse torque F1 provided by the motor gradually increases. 1后 =F 1前 +(-dir*F 定 ), F 定 It is a fixed torque value. When the motor rotates in the forward direction, dir is 1, otherwise dir is -1.

7. The parking safety control method of a brushless hub motor based on reverse torque according to claim 1, characterized in that: In step S2, record the stop start time T 始 .

8. The method for safely controlling the parking of a brushless hub motor based on reverse torque according to claim 1, characterized in that: F2=-Kp*Pos+SumI,SumI 后 =SumI 前 +(-Spd*ki); where Kp is the moving distance adjustment parameter, Pos is the moving distance, which is positive when moving forward and negative when moving backward; SumI is the speed adjustment integral value, Spd is the rotation speed, which is positive when moving forward and negative when moving backward, and ki is the adjustment ratio; if Spd*SumI>0, SumI is cleared and SumI is recalculated. 后 .

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