Automatic power-assisted control method, system and equipment for electric wheelchair

Abstract

The invention relates to the technical field of electric wheelchair control, and discloses an automatic power-assisted control method, system and equipment for an electric wheelchair, and the method comprises the steps: responding to a power-assisted starting instruction sent by a power-assisted switch module, and obtaining the back electromotive force of a motor and the position information of a motor rotor; according to the back electromotive force of the motor and the position information of the motor rotor, the thrust direction of the electric wheelchair is determined; the actual output power of the motor is obtained, the actual output power of the motor is adjusted by combining the thrust direction of the electric wheelchair and the counter electromotive force of the motor, and the preset assistance strength requirement is met. Power is started through the power-assisted switch module, the thrust direction is judged by combining the positions of the motor and the motor rotor, high-price sensors for torque, angle and the like do not need to be additionally arranged, the control structure is simplified, the cost is reduced, and the actual output power is dynamically adjusted by obtaining the actual output power of the motor and combining the thrust direction and the counter electromotive force of the motor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric wheelchair control, in particular to an automatic power-assisted control method, system and device for electric wheelchair. BACKGROUND

[0002] Electric wheelchairs and scooters provide great help for users with difficulty in moving in daily life, however, in some cases, wheelchair users cannot control the wheelchair by themselves and need others to push it. In this case, the pusher needs to maintain the pushing action for a long time, especially when driving on a long distance or steep slope, which is often very tiring and increases the physical burden of the pusher, affecting the use experience of the electric wheelchair or scooter. Traditional power-assisted systems mostly rely on additional sensing devices or complex motor control, increasing the cost of the device and the complexity of the system. SUMMARY

[0003] Therefore, the present application provides an automatic power-assisted control method, system and device for electric wheelchair to solve the problem of high cost and complex control caused by relying on additional sensing devices in the prior art.

[0004] In a first aspect, the present application provides an automatic power-assisted control method for electric wheelchair, the electric wheelchair comprising a motor and a power-assisted switch module, the method comprising: in response to the start power-assisted instruction issued by the power-assisted switch module, acquiring the back electromotive force of the motor and the position information of the motor rotor; determining the pushing direction of the electric wheelchair according to the back electromotive force of the motor and / or the position information of the motor rotor; acquiring the actual output power of the motor, and combining the pushing direction of the electric wheelchair and the back electromotive force of the motor to adjust the actual output power of the motor so that the actual output power meets the preset power-assisted intensity requirement.

[0005] The automatic power-assisted control method for electric wheelchair provided by the present application relies on the power-assisted switch module to start power assistance, combines the motor and the motor rotor position to determine the pushing direction, does not need to additionally install high-priced torque, angle and other sensors, simplifies the control structure and reduces the cost, acquires the actual output power of the motor, combines the pushing direction and the back electromotive force of the motor, dynamically adjusts the actual output power to match the preset power-assisted intensity, can adaptively match the pushing demand, effectively reduces the physical burden of the pusher, and is especially suitable for long-time pushing or slope scenarios.

[0006] In an optional embodiment, if it is detected that the start power-assisted instruction disappears or the back electromotive force of the motor is suddenly changed, the direction of the actual output current of the motor is changed so that the electric wheelchair is braked urgently; if the start power-assisted instruction is detected and the back electromotive force of the motor is not suddenly changed, the actual output power of the motor does not need to be adjusted.

[0007] The application provides an automatic power-assisted control method for an electric wheelchair, which can quickly respond to unexpected situations and ensure safety by detecting a starting power-assisted instruction and a motor back electromotive force condition, and changing a motor output current direction to realize emergency braking when the starting power-assisted instruction disappears or the back electromotive force suddenly changes; and the method can avoid unnecessary power adjustment operations, save energy consumption, simplify a control process, and improve the safety and control convenience of the electric wheelchair when there is a starting power-assisted instruction but no back electromotive force change is detected.

[0008] In an optional embodiment, the motor includes three Hall elements, and the thrust direction of the electric wheelchair is determined according to the back electromotive force of the motor and the position information of the motor rotor, including: the voltage change of the three Hall elements is continuously obtained, and the position information of the motor rotor is determined according to the voltage change of the three Hall elements; if the voltage change of the three Hall elements cannot be obtained, the back electromotive force change of the motor is obtained; the rotation direction of the motor is determined according to the position information of the motor rotor and / or the back electromotive force change of the motor, and then the thrust direction of the electric wheelchair is determined according to the rotation direction of the motor.

[0009] The application provides an automatic power-assisted control method for an electric wheelchair, which determines the rotation direction of the motor by the back electromotive force change of the three Hall elements, and then determines the thrust direction of the electric wheelchair, accurately and in real time, controls the thrust direction, determines the rotation direction and the thrust direction by the position information of the motor rotor when the back electromotive force change of the Hall element cannot be obtained, guarantees the continuity and reliability of the determination of the thrust direction, and effectively improves the power accuracy and stability of the electric wheelchair in complex or special situations.

[0010] In an optional embodiment, the actual output power of the motor is obtained, and the actual output power of the motor is adjusted in combination with the thrust direction of the electric wheelchair and the back electromotive force of the motor, including: if it is determined that the rotation direction of the motor is the same as the thrust direction of the electric wheelchair according to the thrust direction of the electric wheelchair and the back electromotive force of the motor, but the actual output power of the motor does not meet the preset power-assisted intensity requirement, the actual output power of the motor is increased; if it is determined that the rotation direction of the motor is opposite to the thrust direction of the electric wheelchair according to the thrust direction of the electric wheelchair and the back electromotive force of the motor, the actual output power of the motor is increased after the rotation direction of the motor is changed, until the actual output power of the motor meets the preset power-assisted intensity requirement.

[0011] The application provides an automatic power-assisted control method for an electric wheelchair, which flexibly controls the electric wheelchair based on the thrust direction of the electric wheelchair, the back electromotive force of the motor and the actual output power of the motor, when the rotating direction of the motor is consistent with the thrust direction but the power is insufficient, the output power is increased to provide sufficient power in time, when the directions of the two are opposite, the rotating direction is changed and then the power is increased, the power assistance can be accurately adjusted, the actual output power meets the preset power assistance intensity requirement, the adaptability and stability of the power assistance of the electric wheelchair are effectively improved, the power assistance that meets the requirement of the user is provided, and the burden of pushing is reduced.

[0012] In an optional implementation, the actual output power meets the preset power assistance intensity requirement, including: The external thrust received by the electric wheelchair is determined according to the back electromotive force of the motor; The driving speed of the electric wheelchair is obtained, and the relationship between the thrust and the driving speed is determined according to the external thrust and the driving speed; The power assistance power required by the motor to generate the thrust is determined according to the relationship between the thrust and the driving speed, and the actual output power is equal to the power assistance power by adjusting the actual output current of the motor.

[0013] The application provides an automatic power-assisted control method for an electric wheelchair, which flexibly controls the electric wheelchair based on the thrust direction of the electric wheelchair, the back electromotive force of the motor and the actual output power of the motor, when the rotating direction of the motor is consistent with the thrust direction but the power is insufficient, the output power is increased to provide sufficient power in time, when the directions of the two are opposite, the rotating direction is changed and then the power is increased, the power assistance can be accurately adjusted, the actual output power meets the preset power assistance intensity requirement, the adaptability and stability of the power assistance of the electric wheelchair are effectively improved, the power assistance that meets the requirement of the user is provided, and the burden of pushing is reduced.

[0014] In an optional implementation, the electric wheelchair further includes an inertial measurement unit, which adjusts the actual output power of the motor in combination with the thrust direction of the electric wheelchair and the back electromotive force of the motor, and further includes: The slope angle of the position of the electric wheelchair is detected by the inertial measurement unit, and the electric wheelchair is determined to be in an uphill state or a downhill state according to the slope angle and the thrust direction of the electric wheelchair; If the electric wheelchair is in the uphill state, the actual output power of the motor is increased; If the electric wheelchair is in the downhill state, the actual output power of the motor is reduced or the motor is reversed.

[0015] The application provides an automatic power assisting control method for an electric wheelchair, which detects a slope angle by using an inertial measurement unit, judges an uphill or downhill state of the electric wheelchair in combination with a thrust direction, increases actual output power of a motor when uphill, can provide more sufficient power assistance, reduces a pushing burden, reduces power or reversely rotates the motor when downhill, can reasonably control a wheelchair speed, guarantees safety, accurately adjusts power assistance according to different slope scenes, and improves comfort, safety and power assistance adaptability of the electric wheelchair when driving on a slope.

[0016] In an alternative embodiment, the motor comprises a first motor and a second motor, and the method further comprises: acquiring a first rotating speed of the first motor and a second rotating speed of the second motor at the same time, and calculating a rotating speed difference between the first rotating speed and the second rotating speed; when the rotating speed difference is greater than an upper limit of a preset rotating speed deviation range, it is determined that the electric wheelchair has a path deviation trend, and then the average output power of the first motor and the second motor is adjusted according to the rotating speed difference, so that the rotating speed difference is within the preset rotating speed deviation range.

[0017] The application provides an automatic power assisting control method for an electric wheelchair, which acquires rotating speeds of two motors and calculates a rotating speed difference, when the rotating speed difference exceeds an upper limit of a preset range, it is determined that the electric wheelchair has a path deviation trend, and then the average output power of the two motors is adjusted, so that the rotating speed difference returns to the preset range, the path deviation of the wheelchair is detected and corrected in time, and the driving stability and direction control accuracy are improved.

[0018] In a second aspect, the application provides an automatic power assisting control system for an electric wheelchair, the electric wheelchair comprising a motor and a power assisting switch module, and the system comprising: a power assisting starting module, configured to acquire back electromotive force of the motor and position information of a motor rotor in response to a starting power assisting instruction issued by the power assisting switch module; a direction determining module, configured to determine a thrust direction of the electric wheelchair according to the back electromotive force of the motor and the position information of the motor rotor; a power assisting adjusting module, configured to acquire actual output power of the motor, and adjust the actual output power of the motor in combination with the thrust direction of the electric wheelchair and the back electromotive force of the motor, so that the actual output power meets a preset power assisting intensity requirement.

[0019] In a third aspect, the application provides an electronic device, comprising a memory and a processor, which are communicatively connected with each other, the memory stores computer instructions, and the processor executes the computer instructions to perform the method of the first aspect or any of the corresponding embodiments thereof.

[0020] In a fourth aspect, the present application provides a computer readable storage medium having stored thereon computer instructions for causing a computer to execute the method of the first aspect or any of the corresponding embodiments thereof. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0022] Figure 1 is a flowchart of an automatic power assistance control method for an electric wheelchair according to an embodiment of the present application; Figure 2 is a flowchart of another automatic power assistance control method for an electric wheelchair according to an embodiment of the present application; Figure 3 is a structural block diagram of an automatic power assistance control system for an electric wheelchair according to an embodiment of the present application; Figure 4 is a hardware structure schematic diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0024] The embodiments of the present application provide an automatic power assistance control method for an electric wheelchair, which judges the thrust direction through the electromotive force and motor rotor position monitored by the motor, so as to achieve the effects of simplifying the power assistance control structure and reducing the cost.

[0025] According to the embodiments of the present application, an automatic power assistance control method for an electric wheelchair is provided. It should be noted that the steps shown in the flowchart of the drawings can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that here.

[0026] An automatic power-assisted control method for an electric wheelchair is provided in the embodiment, which can be used in the computer system mentioned above, and the electric wheelchair comprises a motor, a power-assisted switch module, Figure 1 is a flowchart of the automatic power-assisted control method for an electric wheelchair according to an embodiment of the present application, as shown in the figure, the flowchart comprises the following steps: Figure 1 Step S101: in response to a start power-assisted instruction sent by the power-assisted switch module, acquiring back electromotive force of the motor and position information of a rotor of the motor.

[0027] Specifically, the power-assisted switch module of the electric wheelchair is a power-assisted handle, which is arranged on a pushing handrail at the rear of the electric wheelchair, and is used to sense the operation intention of a pusher. The power-assisted handle is internally provided with a switch. When the switch is pressed (the pusher holds the handle), the start power-assisted instruction is sent, the internal motor controller is triggered, and the power-assisted mode is entered. At this time, the pusher does not need to operate a rocker or other control device, and the power-assisted force is automatically sensed according to the pushing force and provided according to the pushing force. The design of the handle is similar to that of the brake handle of an electric bicycle. When the handle is held, the power-assisted state is entered, and when the handle is released, the power-assisted system is automatically stopped.

[0028] When the motor generates back electromotive force, it indicates that the motor is passively rotating, and the wheelchair is pushed by external force. At this time, the pushing force direction and the pushing force size are further determined according to the position information of the rotor of the motor. The back electromotive force is used to determine whether the pushing force exists or not, and the position information of the rotor is used to determine the speed and direction.

[0029] The motor serves as a driving unit of the electric wheelchair, can provide power support in the power-assisted mode, has reversibility of the electric motor and the generator, can serve as the electric motor to drive power assistance in different working states, can detect voltage changes by using the internal Hall element to determine the rotating direction and the position information of the rotor of the motor, and further determine the pushing force direction.

[0030] The Hall element can sense changes in the magnetic field. When the permanent magnet on the rotor of the motor rotates with the rotor, the magnetic field strength around the Hall element changes. The Hall element outputs corresponding voltage according to the change in the magnetic field. By continuously acquiring the voltage change, the rotating direction of the rotor of the motor can be determined, and the position information of the rotor can be calculated.

[0031] Step S102: determining the pushing force direction of the electric wheelchair according to the back electromotive force of the motor and / or the position information of the rotor of the motor.

[0032] ​Specifically, when the pusher pushes the electric wheelchair, the presence of the pushing force can be determined by whether the back electromotive force of the motor exists, and it is determined whether the electric wheelchair is in a pushed state. Even when the electric wheelchair is running at a low speed or very slowly, the direction of the pushing force of the electric wheelchair can be accurately determined according to the back electromotive force and / or the position information of the motor rotor, and the power assistance function is automatically activated when the electric wheelchair is in the pushed state. Without additional sensing devices, the system can provide consistent power assistance effect under various terrains, and this process does not require the user to operate through a joystick or other control device, and the power assistance is automatically performed according to the force applied by the pusher.

[0033] In step S103, the actual output power of the motor is obtained, and the actual output power of the motor is adjusted in combination with the pushing force direction of the electric wheelchair and the back electromotive force of the motor, so that the actual output power meets the preset power assistance intensity requirement.

[0034] Specifically, the electric wheelchair precisely controls the current of the motor by using a vector control module to realize dynamic adjustment of the power assistance, and the vector control is also called field-oriented control (FOC). According to the pushing force applied by the pusher, the FOC module is used to control the motor for dynamic adjustment to provide appropriate power assistance to the wheels, thereby effectively assisting the pusher.

[0035] The actual output power of the motor before power assistance is detected, and the output power of the motor is precisely adjusted by controlling the size of the current to ensure the naturalness and continuity during the pushing process and reduce the physical exertion of the pusher. After receiving the start power assistance instruction, the FOC control module combines the back electromotive force, the motor rotor position and the speed information fed back by the motor, applies appropriate current and voltage, and ensures the smoothness and comfort of the power assistance during the pushing process. The power assistance intensity can be dynamically adjusted according to the pushing force of the pusher and the real-time back electromotive force feedback to realize smooth user experience. The power assistance intensity is adjusted in real time according to the pushing force of the pusher to ensure that appropriate power assistance is provided, and unnatural acceleration or deceleration does not occur during the pushing process.

[0036] The automatic power assistance control method for the electric wheelchair provided in the embodiment starts power assistance by relying on the power assistance switch module, determines the pushing force direction in combination with the motor and the motor rotor position, does not need to additionally install high-priced torque, angle and other sensors, simplifies the control structure and reduces the cost. By obtaining the actual output power of the motor, combining the pushing force direction and the back electromotive force of the motor, and dynamically adjusting the actual output power to match the preset power assistance intensity, the pushing demand can be adaptively matched, the physical burden of the pusher can be effectively reduced, and the method is especially suitable for long-time pushing or slope scenarios.

[0037] In the embodiment, an automatic power assistance control method for an electric wheelchair is provided, which can be used in the computer system described above, Figure 2is a flow chart of an automatic power-assisted control method for an electric wheelchair according to an embodiment of the present application, as shown in Figure 2 The flow chart includes the following steps: In step S201, the back electromotive force of the motor and the position information of the motor rotor are acquired in response to the start power-assisted instruction issued by the power-assisted switch module. The detailed content has been described in step S101 shown in Figure 1

[0038] In some optional embodiments, to ensure that the electric wheelchair automatically stops in the case of accidental hand release, the pusher falling down, or crowded environment, an emergency braking module is configured for the electric wheelchair to control the emergency situation. During the power-assisted pushing process, if it is detected that the start power-assisted instruction disappears (the handle is released) or the back electromotive force of the motor suddenly changes (the motor speed abnormally rises) or other emergency situations require braking, the FOC control motor enters the emergency braking mode to immediately stop the power assistance and change the actual output current direction of the motor (for example, reverse for 200-400 ms) to make the electric wheelchair emergency brake and ensure that the electric wheelchair stops in the shortest distance. The emergency braking is suitable for unexpected situations, such as sudden obstacles or the pusher losing control of the electric wheelchair, which can effectively protect the safety of the pusher and the passenger. A double-redundancy protection circuit, such as a relay hard cutoff and an MCU low-power IO switch, can be designed to ensure that the drive circuit is forcibly cut off in an abnormal state, and the physical layer ensures that the electric wheelchair stops.

[0039] If the start power-assisted instruction is detected and the back electromotive force of the motor is not detected to change, the actual output power of the motor does not need to be adjusted.

[0040] Specifically, in contrast to the emergency braking situation, if the start power-assisted instruction is detected, it means that the pusher is controlling the electric wheelchair, and the back electromotive force of the motor is not detected to change, which means that the speed of the electric wheelchair does not change, and the electric wheelchair is in a controllable state, so the emergency braking does not need to be triggered, and the existing state of the electric wheelchair can be maintained.

[0041] The automatic power-assisted control method for an electric wheelchair provided in the embodiment can quickly respond to unexpected situations and protect safety by detecting the start power-assisted instruction and the back electromotive force of the motor and taking corresponding measures, such as changing the output current direction of the motor to achieve emergency braking when the start power-assisted instruction disappears or the back electromotive force changes. When the start power-assisted instruction is detected but the back electromotive force is not detected to change, the output power of the motor does not need to be adjusted, which can avoid unnecessary power adjustment operations, save energy consumption, simplify the control process, and improve the safety and control convenience of the electric wheelchair.

[0042] In step S202, the thrust direction of the electric wheelchair is determined according to the back electromotive force of the motor and / or the position information of the motor rotor.

[0043] ​Specifically, the motor includes three Hall elements, and the step S202 includes: In step S2021, the voltage changes of the three Hall elements are continuously acquired, and the position information of the motor rotor is determined according to the voltage changes of the three Hall elements.

[0044] Specifically, as the motor rotor rotates, the magnetic field around the three Hall elements of the motor changes to generate corresponding voltage changes. The voltage signals of the three Hall elements are continuously collected and monitored. By analyzing the combination rules of the three voltage changes (such as the high and low of the voltages of different Hall elements, phase difference, etc.), the rotation direction of the motor, clockwise or counterclockwise, is determined.

[0045] In some special cases, when the voltage changes of the three Hall elements cannot be normally acquired, a specific position detection device (for example, an encoder) can be used to acquire the position information of the motor rotor at the previous sampling time and the position information at the current sampling time, and by comparing the position information at the two adjacent sampling times, the position change of the motor rotor is determined, including but not limited to the offset of the motor rotor position and the angle of change.

[0046] In step S2022, if the voltage changes of the three Hall elements cannot be acquired, the back electromotive force change of the motor is acquired.

[0047] Specifically, the back electromotive force change of the motor determines the rotation direction of the motor as an auxiliary means. If the voltage changes of the three Hall elements cannot be acquired, it means that the Hall elements may have failed, resulting in loss or abnormality of the Hall sensor signal. At this time, the backup scheme is started: the back electromotive force change of the motor is acquired, and the thrust direction of the electric wheelchair is determined by the back electromotive force change.

[0048] In step S2023, the rotation direction of the motor is determined according to the position information of the motor rotor and / or the back electromotive force change of the motor, and then the thrust direction of the electric wheelchair is determined according to the rotation direction of the motor.

[0049] Specifically, the motor is a core component for providing thrust to the electric wheelchair, and the rotation direction of the motor directly determines the thrust direction of the electric wheelchair. After the rotation direction of the brushless motor is determined, the thrust direction of the electric wheelchair can be determined accordingly, for example, when the motor rotates clockwise, the wheelchair obtains forward thrust; when the motor rotates counterclockwise, the wheelchair obtains backward thrust, which is only an example, but is not limited thereto.

[0050] According to the position change of the motor rotor, the rotation direction of the motor is determined, for example, the rotor position moves from point A to point B. If the moving direction is clockwise, it is determined that the motor rotates clockwise; if it is counterclockwise, it is determined that the motor rotates counterclockwise. After the rotation direction of the motor is determined, the thrust direction of the electric wheelchair is determined according to the rotation direction of the motor according to the above logic.

[0051] The automatic power-assisted control method for the electric wheelchair provided by the embodiment determines the rotation direction of the motor by using the back electromotive force change of the three Hall elements, and then determines the thrust direction of the electric wheelchair, so as to accurately and timely control the thrust direction. When the back electromotive force change of the Hall element cannot be obtained, the rotation direction and the thrust direction are determined by means of the motor rotor position information, so as to ensure the continuity and reliability of the determination of the thrust direction and effectively improve the power-assisted accuracy and stability of the electric wheelchair in complex or special situations.

[0052] In step S203, the actual output power of the motor is obtained, and the actual output power of the motor is adjusted in combination with the thrust direction of the electric wheelchair and the back electromotive force of the motor, so that the actual output power meets the preset power-assisted intensity requirement.

[0053] Specifically, the above step S203 includes: In step S2031, if it is determined according to the thrust direction of the electric wheelchair and the back electromotive force of the motor that the rotation direction of the motor is the same as the thrust direction, but the actual output power of the motor does not meet the preset power-assisted intensity requirement, the actual output power of the motor is increased.

[0054] Specifically, the rotation direction of the motor and the thrust direction are determined in combination with the thrust direction of the electric wheelchair and the back electromotive force of the motor. When it is determined that the directions of the two are the same, but the actual output power of the motor does not meet the preset power-assisted intensity requirement at this time, the actual output power of the motor is increased to improve the power-assisted effect.

[0055] In step S2032, if it is determined according to the thrust direction of the electric wheelchair and the back electromotive force of the motor that the rotation direction of the motor is opposite to the thrust direction, the actual output power of the motor is increased after the rotation direction of the motor is changed until the actual output power of the motor meets the preset power-assisted intensity requirement.

[0056] Specifically, if the rotation direction of the motor is opposite to the thrust direction, the rotation direction of the motor is first changed to be consistent with the thrust direction, and then the actual output power of the motor is increased, and the adjustment is continued until the actual output power of the motor meets the preset power-assisted intensity requirement, so as to ensure that the power-assisted direction is correct and the intensity is sufficient.

[0057] In step S2033, the external thrust received by the electric wheelchair is determined according to the back electromotive force of the motor.

[0058] Specifically, the back electromotive force of the motor and the external thrust received by the electric wheelchair are related. By detecting and analyzing the back electromotive force of the motor, the external thrust received by the electric wheelchair can be determined, which provides a basis for subsequent power adjustment.

[0059] Step S2034, the driving speed of the electric wheelchair is acquired, and the relationship between the pushing force and the driving speed is determined according to the external pushing force and the driving speed.

[0060] Specifically, the driving speed of the electric wheelchair is acquired by using a speed detection device (such as an encoder), and then the relationship between the pushing force and the driving speed, such as the law of the change of the pushing force with the speed, is analyzed and determined in combination with the external pushing force determined in step S2033, which is helpful for more accurate adjustment of the assist power subsequently.

[0061] Step S2035, the assist power required for the motor to generate the pushing force is determined according to the relationship between the pushing force and the driving speed, and the actual output power is made equal to the assist power by adjusting the actual output current of the motor.

[0062] Specifically, the assist power required for the motor to generate the corresponding pushing force is calculated according to the relationship between the pushing force and the driving speed. Then, the actual output power of the motor is made equal to the calculated assist power by adjusting the actual output current of the motor, so as to realize accurate assist control and make the assist of the electric wheelchair highly match the actual demand.

[0063] For the adjustment of the actual output power of the electric wheelchair, the target current value and the actual current value can be closed-loop controlled by using a PID controller, so as to make the actual output current value quickly converge to the target current value. The PID control is a mature prior art, which will not be described here.

[0064] The automatic assist control method for the electric wheelchair provided in the embodiment can flexibly control the electric wheelchair based on the pushing force direction of the electric wheelchair, the back electromotive force of the motor and the actual output power. When the rotating direction of the motor is consistent with the pushing force direction but the power is insufficient, the output power is increased, so as to provide sufficient assist in time. When the two directions are opposite, the rotating direction is changed first and then the power is increased, so as to accurately adjust the assist and ensure that the actual output power meets the preset assist intensity requirement, thereby effectively improving the adaptability and stability of the assist of the electric wheelchair, providing more suitable assist for the user and reducing the pushing burden. The external pushing force of the electric wheelchair is determined according to the back electromotive force of the motor, and then the relationship between the pushing force and the speed is determined in combination with the driving speed, so as to determine the assist power of the motor and adjust the output current, so that the actual power is equal to the assist power. In this way, the assist demand under different external pushing forces and driving speeds can be accurately matched, the assist of the electric wheelchair is more suitable for the actual use scene, the pushing burden is effectively reduced, the comfort and convenience of use are improved, and the working state of the motor is also optimized, thereby improving the energy efficiency of the whole system.

[0065] In some optional embodiments, the electric wheelchair further comprises an inertia measurement unit, which adjusts the actual output power of the motor in combination with the pushing force direction of the electric wheelchair and the back electromotive force of the motor, and further comprises: Step S2036, the slope angle of the position where the electric wheelchair is located is detected by using the inertial measurement unit, and the electric wheelchair is determined to be in an uphill state or a downhill state according to the slope angle and the thrust direction of the electric wheelchair.

[0066] Specifically, the inertial measurement unit (IMU) is built in, the inclination angle of the electric wheelchair can be detected by using the IMU, and then the slope angle of the position where the electric wheelchair is located is determined, the change of the back electromotive force and the change of the motor rotor are combined with the feedback of the Hall element, and the motion state of the electric wheelchair under different slopes and different terrains is recognized.

[0067] Step S2037, if the electric wheelchair is in an uphill state, the actual output power of the motor is increased.

[0068] Specifically, the IMU detects the slope angle through a three-axis acceleration sensor, when the slope angle is greater than an uphill angle threshold (for example, 5°), it indicates that the electric wheelchair is in an uphill state. When the electric wheelchair is detected to be in an uphill state, the FOC controller actively enhances the output current and increases the thrust of the uphill to provide stronger assistance.

[0069] Step S2038, if the electric wheelchair is in a downhill state, the actual output power of the motor is reduced or the motor is reversed.

[0070] Specifically, when the slope angle is less than a downhill angle threshold (for example, -5°), it indicates that the electric wheelchair is in a downhill state. When the electric wheelchair is detected to be in a downhill state or an inertial sliding state, the output torque is reduced or even a reverse current is applied for speed control, realizing a function similar to "light braking", thereby improving the overall comfort and safety of the pusher and the passenger. In addition, the angle of the vehicle body and the change of the environment can be perceived by combining external sensors (such as an accelerometer or a gyroscope), and the assistance control is further optimized.

[0071] The system is not only suitable for assisting in pushing on flat ground, but also has good adaptability on complex terrains such as slopes and grasslands. The FOC controller obtains real-time motion information of the vehicle through the Hall element and other auxiliary sensors, and judges and adjusts different terrain conditions. When uphill, the system increases the assistance of pushing, and when downhill, it applies a slight braking force to prevent the vehicle from losing control, thereby improving the intelligent level of the assisted pushing.

[0072] The automatic power assisting control method for the electric wheelchair provided by the embodiment detects the slope angle by using an inertial measurement unit, judges the uphill or downhill state of the electric wheelchair in combination with the thrust direction, increases the actual output power of the motor when uphill, can provide more sufficient power assistance, and reduces the pushing burden; reduces the power or reverses the rotation of the motor when downhill, can reasonably control the speed of the wheelchair, ensures safety, accurately adjusts the power assistance according to different slope scenarios, and improves the comfort, safety and power assistance adaptability of the electric wheelchair when driving on a slope.

[0073] In an optional embodiment, the motor includes a first motor and a second motor, and the method further includes: In step a1, the first speed of the first motor and the second speed of the second motor at the same time are obtained, and the speed difference between the first speed and the second speed is calculated.

[0074] Specifically, the speed difference and the yaw trajectory of the left and right wheels of the electric wheelchair are calculated by using the Hall element and the IMU direction sensing module, the path is corrected when the wheels are slightly inclined or skid, the vehicle is always kept running in the straight pushing direction, and the method is particularly suitable for the scenes with high requirements for path stability, such as hospital corridors, shopping mall passages and other flat or long walkways, and the direction deviation caused by power assistance is avoided.

[0075] Since the wheels of the electric wheelchair are driven by the motor, the corresponding relationship between the wheel speed and the corresponding motor speed can be determined according to the parameters of the wheel and the parameters of the motor, and this method is a mature existing technology, which will not be described here. In the actual detection process, the first speed R_L of the first motor (corresponding to the motor of the left wheel) and the second speed R_R of the second motor (corresponding to the motor of the right wheel) are obtained in real time by using the Hall element, and the difference between the first speed and the second speed at the same time is calculated: |R_L - R_R|.

[0076] When the speed difference is greater than the upper limit of the preset speed deviation range, it is determined that the electric wheelchair has a path deviation trend, and then the average output power of the first motor and the second motor is adjusted according to the speed difference, so that the speed difference is within the preset speed deviation range.

[0077] Specifically, when the speed difference is greater than the upper limit of the preset speed deviation range, |R_L - R_R|>Δr, it is determined that the electric wheelchair has a path deviation trend; when determining whether there is a path deviation trend, the left wheel linear speed v_L and the right wheel linear speed v_R of the electric wheelchair can also be determined based on the first speed of the first motor and the second speed of the second brushless motor, and the speed difference Δv=|v_L - v_R| between the two wheels is determined based on the left wheel linear speed and the right wheel linear speed. When the speed difference is greater than the speed threshold, it indicates that there is a path deviation trend.

[0078] After determining the path deviation trend, the average output power of the first motor and the second motor needs to be adjusted according to the speed difference, and the speed of the two wheels is adjusted by fine-tuning the PWM duty cycle: , wherein K represents the adjustment gain, and the speed symmetry of the left and right wheels is ensured by the PWM duty cycle adjustment, thereby maintaining the stability of the direction.

[0079] The automatic power assisting control method for the electric wheelchair provided in the embodiment is to obtain the speeds of the two motors and calculate the speed difference, determine that the electric wheelchair has a path deviation trend when the speed difference exceeds the upper limit of the preset range, and then adjust the average output power of the two motors to make the speed difference return to the preset range, so as to timely perceive and correct the path deviation of the wheelchair, and improve the driving stability and the accuracy of direction control.

[0080] In a specific embodiment, the power assisting switch module is installed at the pushing handle position of the electric wheelchair, and the structure is similar to the brake handle of an electric bicycle. A normally closed Hall switch or a photoelectric switch is built-in, and a signal is triggered when the handle is gripped, and the FOC enters the standby power assisting mode.

[0081] When the vehicle is not started and the rear wheels are rotating, the brushless motor works as a generator, and the rotor cuts the magnetic lines to induce a back electromotive force at both ends of the coil. Whether the back electromotive force voltage exceeds the set threshold (for example, ±2.5V) is detected to determine whether it is pushed by external force.

[0082] Pushing recognition and resultant force determination logic: ① handle pressed + back electromotive force changed Start FOC power assisting; ② if the handle is not pressed + back electromotive force suddenly increases Start the warning logic, and do not enter the power assisting; ③ if the handle is pressed + no back electromotive force The motor is on standby, and no force is output to prevent idling. This logic avoids false triggering and ensures that effective power assisting is provided only when the wheelchair is pushed by a person and the handle is gripped, thereby improving safety and experience.

[0083] In the embodiment, an automatic power assisting control system for an electric wheelchair is also provided, which is used to implement the above-mentioned embodiments and preferred embodiments, and will not be described again. As used below, the term "module" can be a combination of software and / or hardware that implements a predetermined function. Although the system described in the following embodiments is preferably implemented in software, hardware, or a combination of software and hardware is also possible and contemplated.

[0084] The embodiment provides an automatic power assisting control system for an electric wheelchair, and the electric wheelchair comprises a motor and a power assisting switch module. Figure 3 As shown in the figure, the system comprises: The power-assisted start module 301 is used to respond to the power-assisted start command issued by the power-assisted switch module and obtain the back electromotive force of the motor and the position information of the motor rotor.

[0085] The direction determination module 302 is used to determine the thrust direction of the electric wheelchair based on the back electromotive force of the motor and / or the position information of the motor rotor.

[0086] The assist adjustment module 303 is used to obtain the actual output power of the motor and adjust the actual output power of the motor in combination with the thrust direction of the electric wheelchair and the back electromotive force of the motor so that the actual output power meets the preset assist intensity requirements.

[0087] Further functional descriptions of the above modules are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0088] In this embodiment, the automatic power assist control system for electric wheelchairs is presented in the form of functional units. Here, a unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that execute one or more software or fixed programs, and / or other devices that can provide the above functions.

[0089] This invention also provides an electronic device having the above-described features. Figure 3 The diagram shows an automatic power assist control system for an electric wheelchair.

[0090] Please see Figure 4 , Figure 4 This is a schematic diagram of the structure of an electronic device provided in an optional embodiment of the present invention, such as... Figure 4 As shown, the electronic device includes one or more processors 10, memory 20, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. The components communicate with each other via different buses and can be mounted on a common motherboard or otherwise as required. The processors can process instructions executed within the electronic device, including instructions stored in or on memory to display graphical information of a GUI on external input / output devices (such as display devices coupled to the interfaces). In some alternative implementations, multiple processors and / or multiple buses can be used with multiple memories and multiple memory modules, if desired. Similarly, multiple electronic devices can be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system). Figure 4 Take a processor 10 as an example.

[0091] The processor 10 can be a central processing unit, a network processing unit, or a combination thereof. The processor 10 can further include a hardware chip. The hardware chip can be an application specific integrated circuit, a programmable logic device, or a combination thereof. The programmable logic device can be a complex programmable logic device, a field programmable logic device, a general array logic, or any combination thereof.

[0092] The memory 20 stores instructions executable by the at least one processor 10 to cause the at least one processor 10 to perform the methods illustrated in the above embodiments.

[0093] The memory 20 can include a program storage area and a data storage area. The program storage area can store an operating system and application programs required by at least one function. The data storage area can store data created according to the use of the electronic device, etc. In addition, the memory 20 can include a high-speed random access memory, and can further include a non-transitory memory such as at least one disk storage device, a flash memory device, or other non-transitory solid-state memory device. In some alternative embodiments, the memory 20 can optionally include a memory disposed remotely with respect to the processor 10, and these remote memories can be connected to the electronic device through a network. Examples of the network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof.

[0094] The memory 20 can include a volatile memory such as a random access memory, and can further include a non-volatile memory such as a flash memory, a hard disk, or a solid state disk. The memory 20 can further include a combination of the above-mentioned types of memories.

[0095] The electronic device further includes a communication interface 30 for communication of the electronic device with other devices or communication networks.

[0096] The embodiments of the present application also provide a computer readable storage medium. The above-mentioned methods according to the embodiments of the present application can be implemented in hardware, firmware, or recorded in a storage medium, or stored in a remote storage medium or a non-transitory machine readable storage medium originally downloaded through a network and stored in a local storage medium, so that the methods described herein can be processed by such software on a storage medium using a general purpose computer, a special purpose processor, or programmable or special purpose hardware. The storage medium can be a disk, an optical disk, a read-only memory, a random access memory, a flash memory, a hard disk, or a solid state disk, etc. Further, the storage medium can further include a combination of the above-mentioned types of memories. It can be understood that the computer, the processor, the microprocessor controller, or the programmable hardware includes a storage component that can store or receive software or computer code, when the software or computer code is accessed and executed by the computer, the processor, or the hardware, the methods illustrated in the above embodiments are implemented.

[0097] While embodiments of the present application have been described in conjunction with the appended drawings, various modifications and changes are possible within the spirit and scope of the present application, and such modifications and changes are intended to fall within the scope of the appended claims.

Claims

1. An automatic power assist control method for an electric wheelchair, characterized in that, The electric wheelchair includes: a motor and an assist switch module; the method includes: In response to the start assist command issued by the assist switch module, the back electromotive force of the motor and the position information of the motor rotor are obtained. The direction of the thrust of the electric wheelchair is determined based on the back electromotive force of the motor and / or the position information of the motor rotor. The actual output power of the motor is obtained, and the actual output power of the motor is adjusted in combination with the thrust direction of the electric wheelchair and the back electromotive force of the motor so that the actual output power meets the preset assist strength requirements.

2. The method according to claim 1, characterized in that, If the start-up assist command is detected to have disappeared or the back electromotive force of the motor is suddenly changed, the actual output current direction of the motor is changed to enable the electric wheelchair to brake in an emergency. If the start-up assist command is detected and no sudden change in the back electromotive force of the motor is detected, then there is no need to adjust the actual output power of the motor.

3. The method according to claim 1 or 2, characterized in that, The motor includes three Hall elements, which determine the thrust direction of the electric wheelchair based on the back electromotive force of the motor and / or the position information of the motor rotor, including: The voltage changes of the three Hall elements are continuously acquired, and the position information of the motor rotor is determined based on the voltage changes of the three Hall elements. If the voltage changes of the three Hall elements cannot be obtained, then the back electromotive force change of the motor is obtained; Based on the position information of the motor rotor and / or the change in the back electromotive force of the motor, the rotation direction of the motor is determined, and then the thrust direction of the electric wheelchair is determined based on the rotation direction of the motor.

4. The method according to claim 1, characterized in that, Obtaining the actual output power of the motor and adjusting the actual output power of the motor in conjunction with the thrust direction of the electric wheelchair and the back electromotive force of the motor includes: If the direction of motor rotation is determined to be the same as the direction of thrust based on the direction of thrust of the electric wheelchair and the back electromotive force of the motor, but the actual output power of the motor does not meet the preset assist strength requirement, then the actual output power of the motor is increased. If the direction of motor rotation is determined to be opposite to the direction of thrust based on the direction of thrust of the electric wheelchair and the back electromotive force of the motor, then the actual output power of the motor is increased after changing the direction of motor rotation until the actual output power of the motor meets the preset assist strength requirement.

5. The method according to claim 1, characterized in that, To ensure that the actual output power meets the preset assist strength requirement, the following measures are taken: The external thrust on the electric wheelchair is determined based on the back electromotive force of the motor. The driving speed of the electric wheelchair is obtained, and the relationship between the thrust and the driving speed is determined based on the external thrust and the driving speed. Based on the relationship between the thrust and the travel speed, the required power output of the motor to generate the thrust is determined, and the actual output current of the motor is adjusted to make the actual output power equal to the power output.

6. The method according to claim 1 or 4, characterized in that, The electric wheelchair also includes: an inertial measurement unit, which adjusts the actual output power of the motor based on the thrust direction of the electric wheelchair and the back electromotive force of the motor; and further includes: The inertial measurement unit is used to detect the slope angle of the electric wheelchair's location, and the electric wheelchair is determined to be in an uphill or downhill state based on the slope angle and the direction of the electric wheelchair's thrust. If the electric wheelchair is going uphill, the actual output power of the motor is increased; If the electric wheelchair is going downhill, reduce the actual output power of the motor or make the motor rotate in the opposite direction.

7. The method according to claim 1, characterized in that, The motor includes: a first motor and a second motor; the method further includes: Obtain the first speed of the first motor and the second speed of the second motor at the same moment, and calculate the speed difference between the first speed and the second speed; When the speed difference is greater than the upper limit of the preset speed deviation range, it is determined that the electric wheelchair has a path deviation trend. Then, the average output power of the first motor and the second motor is adjusted according to the speed difference so that the speed difference is within the preset speed deviation range.

8. An automatic power assist control system for an electric wheelchair, characterized in that, The electric wheelchair includes: a motor and an assist switch module; the system includes: The power-assisted start module is used to respond to the start-assisted command issued by the power-assisted switch module and obtain the back electromotive force of the motor and the position information of the motor rotor. The direction determination module is used to determine the thrust direction of the electric wheelchair based on the back electromotive force of the motor and the position information of the motor rotor. The assist adjustment module is used to obtain the actual output power of the motor and adjust the actual output power of the motor in combination with the thrust direction of the electric wheelchair and the back electromotive force of the motor so that the actual output power meets the preset assist intensity requirements.

9. An electronic device, characterized in that, include: A memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, the processor executing the computer instructions to perform the method of any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing the computer to perform the method of any one of claims 1 to 7.

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