Device with power-assisted wheel and control method of power-assisted wheel

Abstract

The invention relates to the technical field of power-assisted wheel control, in particular to a device with a power-assisted wheel and a control method of the power-assisted wheel. The method comprises the steps that the speed and the direction of a power-assisted wheel are continuously obtained, and the accelerated speed and the speed change rate are calculated according to the speed; the power assisting direction of the power assisting wheel is judged according to the speed direction, and the power assisting value of the power assisting wheel is adjusted in the power assisting direction based on the speed and the acceleration of the power assisting wheel; the steering tendency is judged based on the speed change rate and the speed direction of the power-assisted wheel, and when it is judged that the power-assisted wheel has the steering tendency, control parameters of a driving motor of the power-assisted wheel are adjusted, and steering operation of the power-assisted wheel is achieved; whether the power-assisted wheel slips or not is judged according to the speed difference between the speed of the power-assisted wheel and the speed of a preset reference object, and the output torque of the driving motor is reduced when it is judged that the power-assisted wheel slips. Through control of the power-assisted wheel, physical exhaustion of operators is reduced to a certain extent, manpower resources are saved, and the working efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of assist wheel control, and particularly to a device with an assist wheel and a control method for the assist wheel. Background Art

[0002] With the improvement of people's living standards, floor scrubbers, as an efficient floor cleaning device, have been widely used. During the use of floor scrubbers, the control of the assist wheel is crucial for the user experience and device performance. Currently, there are some problems in the control of the assist wheel of existing floor scrubbers. For example, it is impossible to accurately adjust the assistance, resulting in difficulty for users to push or excessive assistance that is difficult to control; the commutation is not smooth enough, affecting the use experience; at the same time, the detection and handling of assist wheel slipping are not timely and effective enough, easily damaging the device components and having a poor cleaning effect. Therefore, there is an urgent need for a more intelligent and accurate control method and device for the assist wheel. Summary of the Invention

[0003] To solve the above problems, the present invention provides a device with an assist wheel and a control method for the assist wheel, which can accurately control the assistance of the assist wheel, achieve a smooth speed change and commutation, effectively detect and avoid slipping, and improve the user experience and device performance.

[0004] The technical solution adopted by the present invention is: an assist wheel control method, including:

[0005] Continuously obtain the speed and direction of the assist wheel, and calculate the acceleration and the rate of change of speed according to the speed of the assist wheel;

[0006] Judge the assistance direction of the assist wheel according to the speed direction, and adjust the assistance value of the assist wheel in the assistance direction based on the speed and acceleration of the assist wheel;

[0007] Judge the steering tendency based on the rate of change of speed and the speed direction of the assist wheel, and when it is judged that the assist wheel has a steering tendency, adjust the control parameters of the drive motor of the assist wheel to achieve the steering operation of the assist wheel;

[0008] Judge whether the assist wheel slips according to the speed difference between the speed of the assist wheel and the speed of a preset reference object, and reduce the output torque of the drive motor when it is judged that slipping occurs.

[0009] A further improvement to the above solution is that the judging of the steering tendency based on the rate of change of speed and the speed direction of the assist wheel includes:

[0010] When it is judged according to the rate of change of speed of the assist wheel that the speed of the assist wheel gradually decreases from the positive direction and approaches zero, and there is a subsequent trend of increasing in the reverse direction, it is judged that the assist wheel has a steering tendency.

[0011] A further improvement to the above solution is that the continuously obtaining the speed and direction of the assisting wheel includes:

[0012] By means of two linear Hall sensors inside the drive motor built in the assisting wheel to output HALL_A and HALL_B sine wave signals, according to the characteristic that HALL_A and HALL_B have a 90° phase difference, when the assisting wheel rotates forward, the HALL_A signal leads the HALL_B signal by 90°; when rotating in reverse, the HALL_B signal leads the HALL_A signal by 90°. The drive motor internally calculates the rotational speed by regularly monitoring the change rate of the phase difference, and combines the direction judgment result to output a signed rotational speed value, so as to obtain the speed and direction of the assisting wheel.

[0013] A further improvement to the above solution is that the judging the assisting direction of the assisting wheel according to the speed direction and adjusting the assisting value of the assisting wheel in the assisting direction based on the speed and acceleration of the assisting wheel includes:

[0014] If the current speed of the assisting wheel is less than the first preset speed threshold and the acceleration is positive, then increase the assisting value by the first amplitude;

[0015] If the current speed of the assisting wheel is greater than the second preset speed threshold and the acceleration is negative, then decrease the assisting value by the second amplitude.

[0016] A further improvement to the above solution is that the assisting wheel is a single assisting wheel, and the judging whether the assisting wheel slips according to the speed difference between the speed of the assisting wheel and the speed of a preset reference object includes:

[0017] Calculate the difference between the real-time speed and the no-load speed of the assisting wheel and the difference between the actual torque and the expected torque;

[0018] When any of the following conditions occurs, it is judged that the assisting wheel slips:

[0019] The difference between the no-load speed and the real-time speed is greater than the first threshold, and the difference between the actual torque and the expected torque is greater than the second threshold; or

[0020] The difference between the no-load speed and the real-time speed is greater than the first threshold and lasts for a preset time; or

[0021] The difference between the actual torque and the expected torque is greater than the second threshold and lasts for a preset time.

[0022] A further improvement to the above solution is that the method further includes:

[0023] According to the current working mode of the floor washer, the set speed and the ground resistance, calculate the expected torque through the established torque-speed-resistance mathematical model.

[0024] A further improvement to the above solution is that the assisting wheel is a double assisting wheel, and determining whether the assisting wheel slips according to the speed difference between the speed of the assisting wheel and the speed of a preset reference object includes:

[0025] Calculating the speed difference between the two wheels of the assisting wheel;

[0026] When the speed difference is within a preset threshold range, it is determined as normal steering;

[0027] When the speed difference exceeds the preset threshold, it is determined that the speed of one or both wheels is abnormal and a slipping phenomenon occurs.

[0028] A device including an assisting wheel controls the assisting wheel by using the control method described above.

[0029] A further improvement to the above solution is that the device is a floor washer.

[0030] A further improvement to the above solution is that the assisting wheel is a single assisting wheel or a double assisting wheel.

[0031] The beneficial effects of the present invention are as follows: Compared with the existing assisting mechanism, by obtaining the speed of the assisting wheel and dynamically adjusting the assisting value in combination with information such as the speed direction and acceleration, the present invention can provide more in line with the actual needs of the user's assistance, making it easier and more labor-saving to push the floor washer, and improving the user experience; the judgment of the speed change rate and the corresponding assisting value adjustment and commutation preparation strategy ensure that the floor washer runs smoothly during speed change and commutation, avoiding phenomena such as jamming and impact; and the effective slipping detection and avoidance mechanism can timely detect and handle the slipping problem of the assisting wheel, not only protecting the equipment components, extending the service life of the equipment, but also ensuring the normal progress of the cleaning work and improving the cleaning effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A three-dimensional schematic diagram of a floor washer with a single assisting wheel provided by an embodiment of the present invention;

[0033] Figure 2 A three-dimensional schematic diagram of a floor washer with a double assisting wheel provided by another embodiment of the present invention;

[0034] Figure 3 A flowchart of an assisting wheel control method provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0035] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention.

[0037] The present invention provides a device with a booster wheel. The booster wheel is a component that provides additional power for the device. Due to its characteristics such as flexible steering, providing power assistance, and adapting to different terrains, it can be used in floor scrubbers, suitcases, and some model vehicles. In the present invention, the floor scrubber is taken as an example for illustration, that is, the device with a booster wheel described in the present invention is a floor scrubber.

[0038] Referring to Figure 1 As shown, in an embodiment of the present invention, a three-dimensional schematic diagram of a floor scrubber with a single booster wheel is provided. In the embodiment of the present invention, the floor scrubber includes a base 1, a connecting frame 2, a connecting rod 3, and a booster wheel 4. The booster wheel 4 is disposed on the base 1 or the connecting frame 2. The booster wheel 4 is internally provided with a driving motor for providing assistance when the connecting rod 3 pushes the base 1 to move. In addition, the driving motor of the booster wheel internally includes two linear Hall sensors. The two linear Hall sensors output HALL_A and HALL_B sine wave signals. According to the characteristic that HALL_A and HALL_B are 90° out of phase, when the booster wheel rotates forward, the HALL_A signal leads the HALL_B signal by 90°; when rotating backward, the HALL_B signal leads the HALL_A signal by 90°. The driving motor internally calculates the rotational speed by regularly monitoring the change rate of the phase difference, and combines the direction judgment result to finally output a signed rotational speed value. As long as the speed data fed back by the motor serial port is detected, the speed direction and speed of the booster wheel can be judged.

[0039] This embodiment is used for assisting the floor scrubber during use. When the connecting rod 3 pushes the base 1 to move, the driving motor in the booster wheel 4 is started to drive the booster wheel 4 to rotate to provide assistance. In the above embodiment, when the connecting rod 3 pushes the base 1 to move, the booster wheel 4 can provide additional assistance, thereby reducing the burden on the operator and improving the operation efficiency.

[0040] Further, referring to Figure 2As shown in the figure, in another embodiment of the present invention, a floor washer with double assist wheels is further provided. In the floor washer with double assist wheels, two assist wheels 4 are provided, and the two assist wheels 4 are respectively arranged on the outer side surface of the connecting frame 2. At least one of the two assist wheels 4 is internally provided with a driving motor.

[0041] In the above embodiment, through the design of the assist wheels, the physical exertion of the operator can be reduced to a certain extent, thereby saving human resources and improving the working efficiency of the floor washer.

[0042] Further, referring to Figure 3 As shown in the figure, it is a flowchart of the assist wheel control method provided by an embodiment of the present invention. In the embodiment of the present invention, the assist wheel control method includes:

[0043] S1. Continuously obtain the speed and direction of the assist wheel, and calculate the acceleration and the rate of change of speed according to the speed of the assist wheel.

[0044] Further, in the embodiment of the present invention, two-channel linear Hall sensors inside the driving motor built in the assist wheel output HALL_A and HALL_B sine wave signals. According to the characteristic that HALL_A and HALL_B have a 90° phase difference, when the assist wheel rotates forward, the HALL_A signal leads the HALL_B signal by 90°; when rotating backward, the HALL_B signal leads the HALL_A signal by 90°. The driving motor internally calculates the rotational speed by regularly monitoring the rate of change of the phase difference, and combines the direction judgment result to finally output a signed rotational speed value; as long as the speed data fed back by the motor serial port is detected, the speed direction and speed of the assist wheel can be judged.

[0045] Further, in the embodiment of the present invention, based on the continuously collected speed data, the method of numerical differentiation is used to calculate the acceleration, that is, assuming that at two adjacent sampling times t1 and t2 (the sampling interval is Δt = t2 - t1), the measured speeds are v1 and v2 respectively, then the acceleration a = Δt(v2 - v1).

[0046] In addition, in the embodiment of the present invention, the speed data of the assist wheel is continuously collected at a very short time interval (such as 10 ms), and the speed value collected each time is compared with the previous speed value to track the change of the speed in real time and obtain the rate of change of speed.

[0047] S2. Judge the assist direction of the assist wheel according to the speed direction, and adjust the assist value of the assist wheel in the assist direction based on the speed and acceleration of the assist wheel;

[0048] In an embodiment of the present invention, if the current speed of the assist wheel is less than the first preset speed threshold and the acceleration is positive, the assist value is increased by the first amplitude; if the current speed of the assist wheel is greater than the second preset speed threshold and the acceleration is negative, the assist value is decreased by the second amplitude. Wherein, the first amplitude and the second amplitude may be the same or different.

[0049] Adjust the assist value according to the speed magnitude and acceleration conditions, in combination with a preset assist control algorithm. If the current speed is low and the acceleration is positive, appropriately increase the assist value according to the algorithm rules; if the speed is high and the acceleration is negative, decrease the assist value. Provide forward push assist or backward pull assist according to the speed direction.

[0050] S3. Judge the steering tendency based on the speed change rate and speed direction of the assist wheel, and when it is judged that the assist wheel has a steering tendency, adjust the control parameters of the drive motor of the assist wheel to realize the steering operation of the assist wheel;

[0051] In an embodiment of the present invention, when it is judged according to the speed change rate of the assist wheel that the speed of the assist wheel gradually decreases from positive to close to zero and there is a subsequent trend of increasing in the reverse direction, it is judged that the assist wheel has a steering tendency.

[0052] Further, when it is judged that the assist wheel has a steering tendency, the embodiment of the present invention adjusts the control parameters of the drive motor of the assist wheel, such as changing the current direction of the motor, adjusting the drive voltage of the motor, etc., to realize the steering operation of the assist wheel.

[0053] S4. Judge whether the assist wheel slips according to the speed difference between the speed of the assist wheel and the speed of a preset reference object, and reduce the output torque of the drive motor when it is judged that slipping occurs.

[0054] In an embodiment of the present invention, the assist wheel may be a single assist wheel or a double assist wheel.

[0055] When the assist wheel is a single assist wheel, the speed of the preset reference object may be the no-load speed of the assist wheel. In the initial stage of starting the floor washer or during a specific no-load detection stage, record the speed of the assist wheel under no-load conditions as the no-load speed. During normal operation, monitor the actual running speed in real time and calculate the difference between the two; according to factors such as the current working mode of the floor washer, the set speed, and the ground resistance, calculate the expected torque through the established torque-speed-resistance mathematical model, and at the same time use a torque sensor to measure the actual torque output by the assist wheel motor in real time, and compare the actual torque with the expected torque.

[0056] Different floor washing machine working modes may have different characteristics and parameters. For example, standard mode, strong mode, energy-saving mode, etc. Each mode may correspond to different motor powers, speed ranges, and coefficients related to torque. The embodiments of the present invention first clarify the working mode of the current floor washing machine and determine the relevant parameter values in this mode. Ground resistance is an important factor affecting the torque requirement of the floor washing machine. The embodiments of the present invention can determine the ground resistance through various methods such as direct measurement, empirical data, and calculation models.

[0057] When determining the ground resistance using a calculation model, the following method can be adopted: Based on factors such as the material, roughness, humidity of the ground, and the weight of the floor washing machine, the contact area between the cleaning component and the ground, etc., a theoretical ground resistance calculation model is established. For example, according to Coulomb's law of friction, the ground resistance Ff = μ × FN, where μ is the friction coefficient, related to the ground material and state, and FN is the normal pressure of the floor washing machine on the ground, equal to the weight of the floor washing machine.

[0058] Generally speaking, there is a complex relationship between the motor torque T of the floor washing machine, the speed n, and the load resistance (here mainly the ground resistance Ff). Common models can be established based on the characteristic curve of the motor and the mechanical transmission principle. Among them, the torque-speed relationship of the motor can usually be expressed by an approximate quadratic function. For example, T = a × n 2 + b × n + c, where a, b, and c are coefficients related to the motor type and characteristics. These coefficients can be determined through the technical specification of the motor or experimental measurement. The ground resistance will generate an additional load on the motor torque. When the floor washing machine runs at a certain speed, the ground resistance will cause the motor to output a greater torque to overcome the resistance. Assuming the radius of the driving wheel of the floor washing machine is r, the resistance torque Tf generated by the ground resistance is Tf = Ff × r. Therefore, the total torque Ttotal considering the ground resistance is the sum of the motor torque T and the resistance torque Tf, that is, T total = T + Tf. There is a certain transmission relationship between the set speed v of the floor washing machine and the motor speed n. If the diameter d of the driving wheel of the floor washing machine and the transmission ratio i of the transmission system are known, the set speed v can be converted into the motor speed n through the formula n = π × d v × i. Substitute the determined speed n into the motor characteristic equation T = a × n 2 + b × n + c to calculate the torque T of the motor at this speed. Then, according to the measured or estimated ground resistance Ff and the driving wheel radius r, calculate the resistance torque Tf = Ff × r. Finally, add the motor torque T and the resistance torque Tf to obtain the expected torque T total = T + Tf.

[0059] In practical applications, it may be necessary to experimentally verify and correct the established mathematical model to ensure the accuracy of the calculation results. At the same time, other factors of the floor washer, such as battery power, motor heating, mechanical wear, etc., which affect the torque, also need to be considered to calculate the expected torque more accurately.

[0060] Specifically, judging whether the assist wheel slips according to the speed difference between the speed of the assist wheel and the speed of a preset reference object includes:

[0061] Calculating the difference between the real-time speed and the no-load speed of the assist wheel, and the difference between the actual torque and the expected torque;

[0062] When any of the following conditions occurs, it is determined that the assist wheel slips:

[0063] The difference between the no-load speed and the real-time speed is greater than the first threshold, and the difference between the actual torque and the expected torque is greater than the second threshold; or

[0064] When the difference between the no-load speed and the real-time speed is greater than the first threshold and lasts for a preset time, such as 0.5 s; or

[0065] The difference between the actual torque and the expected torque is greater than the second threshold and lasts for a preset time.

[0066] In another embodiment of the present invention, when the assist wheel is a double assist wheel, the speed of the preset reference object can be the speed of the other assist wheel.

[0067] Specifically, judging whether the assist wheel slips according to the speed difference between the speed of the assist wheel and the speed of a preset reference object includes:

[0068] Calculating the speed difference between the two wheels of the assist wheel;

[0069] When the speed difference is within the preset threshold range, it is determined as normal steering;

[0070] When the speed difference exceeds the preset threshold, it is determined that the speed of a single wheel or both wheels is abnormal and a slipping phenomenon occurs.

[0071] Once it is determined that the assist wheel slips, the embodiment of the present invention immediately reduces the current input to the drive motor, reduces the output torque of the drive motor, and at the same time sets a lower maximum torque limit value. When it is detected that the slipping phenomenon is alleviated or eliminated, the torque output of the drive motor is gradually restored to the normal level.

[0072] By obtaining the speed of the assist wheel and dynamically adjusting the assist value in combination with information such as the speed direction and acceleration, the present invention can provide assistance that better meets the actual needs of users, making it easier and more labor-saving to push the floor washer and improving the user experience. The judgment of the rate of change of speed and the corresponding strategies for adjusting the assist value and preparing for commutation ensure that the floor washer operates smoothly during speed changes and commutation, avoiding phenomena such as jamming and impact. In addition, the effective slip detection and avoidance mechanism can timely detect and handle the problem of assist wheel slip, which not only protects the equipment components and extends the service life of the equipment, but also ensures the normal progress of the cleaning work and improves the cleaning effect.

[0073] The above embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims

1. A method for controlling a booster wheel, characterized in that, The method includes: Continuously obtaining the speed and direction of the assist wheel, and calculating the acceleration and the rate of change of speed according to the speed of the assist wheel; Judging the assist direction of the assist wheel according to the speed direction, and adjusting the assist value of the assist wheel in the assist direction based on the speed and acceleration of the assist wheel; Judging the steering tendency based on the rate of change of speed and the speed direction of the assist wheel, and when it is judged that the assist wheel has a steering tendency, adjusting the control parameters of the drive motor of the assist wheel to realize the steering operation of the assist wheel; Judging whether the assist wheel slips according to the speed difference between the speed of the assist wheel and the speed of a preset reference object, and reducing the output torque of the drive motor when it is judged that slipping occurs.

2. The assist wheel control method according to claim 1, wherein The judging the steering tendency based on the rate of change of speed and the speed direction of the assist wheel includes: When it is judged according to the rate of change of speed of the assist wheel that the speed of the assist wheel gradually decreases from positive to near zero and has a tendency to increase in the reverse direction subsequently, it is judged that the assist wheel has a steering tendency.

3. The assist wheel control method according to claim 1, wherein The continuously obtaining the speed and direction of the assist wheel includes: By means of two linear Hall sensor output HALL_A and HALL_B sine wave signals built into the drive motor inside the assist wheel, according to the characteristic that HALL_A and HALL_B have a 90° phase difference, when the assist wheel rotates forward, the HALL_A signal leads the HALL_B signal by 90°; when rotating in the reverse direction, the HALL_B signal leads the HALL_A signal by 90°. The drive motor internally calculates the rotational speed by regularly monitoring the change rate of the phase difference, and combines the direction judgment result to output a signed rotational speed value to obtain the speed and direction of the assist wheel.

4. The assisting wheel control method according to claim 3, wherein The judging the assist direction of the assist wheel according to the speed direction, and adjusting the assist value of the assist wheel in the assist direction based on the speed and acceleration of the assist wheel includes: If the current speed of the assist wheel is less than the first preset speed threshold and the acceleration is positive, increase the assist value by the first amplitude; If the current speed of the assist wheel is greater than the second preset speed threshold and the acceleration is negative, reduce the assist value by the second amplitude.

5. The assist wheel control method according to claim 4, wherein The assist wheel is a single assist wheel, and the judging whether the assist wheel slips according to the speed difference between the speed of the assist wheel and the speed of a preset reference object includes: Calculating the difference between the real-time speed and the no-load speed of the assist wheel and the difference between the actual torque and the expected torque; When any one of the following conditions occurs, it is judged that the assist wheel slips: The difference between the no-load speed and the real-time speed is greater than the first threshold, and the difference between the actual torque and the expected torque is greater than the second threshold; or The difference between the no-load speed and the real-time speed is greater than the first threshold and lasts for a preset time; or The difference between the actual torque and the expected torque is greater than the second threshold and lasts for a preset time.

6. The assist wheel control method according to claim 5, characterized in that The method further includes: Calculating the expected torque according to the current working mode of the floor washer, the set speed and the ground resistance through the established torque-speed-resistance mathematical model.

7. The assist wheel control method according to claim 1, wherein The assist wheel is a double assist wheel, and the judging whether the assist wheel slips according to the speed difference between the speed of the assist wheel and the speed of a preset reference object includes: Calculate the speed difference between the two wheels of the assist wheel; When the speed difference is within the preset threshold range, it is determined as a normal turn; When the speed difference exceeds the preset threshold, it is determined that the speed of one or both wheels is abnormal and a slipping phenomenon occurs.

8. A device comprising an assisting wheel, characterized in that, Control the assist wheel by using the control method according to any one of claims 1 to 7.

9. The device comprising an assisting wheel according to claim 8, characterized in that, The device is a floor washer.

10. The device comprising a booster wheel according to claim 8, characterized in that, The assist wheel is a single assist wheel or a double assist wheel.

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