Electric wheelchair silent test

Electric wheelchair silent test

1. Introduction
In today’s society, with the continuous advancement of science and technology, people’s requirements for the performance and quality of electric wheelchairs are getting higher and higher. In addition to the basic mobility assistance function, the silent performance of electric wheelchairs has also become one of the focuses of users. A quiet operating environment is of great significance to the user’s comfort and privacy protection. Therefore, the silent test of electric wheelchairs has become a key link in ensuring product quality and user experience.

2. The importance of silent testing of electric wheelchairs
Improve user comfort
For users who use electric wheelchairs for a long time, wheelchairs with too much noise can make them feel irritable and may even cause discomfort symptoms such as headaches. Electric wheelchairs with good silent performance can provide users with a quiet and comfortable riding environment, help reduce their physical and mental fatigue, and improve the overall user experience.
Protect user privacy
In some places that require quietness, such as hospitals, libraries, offices, etc., the noise of electric wheelchairs may attract the attention of people around, making users feel embarrassed and feel that they are “exposed”. By silent testing and optimizing the silent performance of wheelchairs, users can move more freely in these places without worrying about noise problems affecting their privacy.
Meeting the needs of the international market
In the international market, different countries and regions may have different noise standards for electric wheelchairs. In order to meet the needs of international wholesale buyers and enable products to meet the access conditions of various markets, electric wheelchair manufacturers must attach importance to quiet testing to ensure that the products meet international standards in terms of noise.

3. Methods for quiet testing of electric wheelchairs
Subjective evaluation method
Definition: The subjective evaluation method is to use professional testers or potential users to subjectively feel and evaluate the noise of electric wheelchairs under different driving conditions. Testers can score and describe the noise from multiple dimensions such as volume, sound quality, and whether it is harsh.
Testing process: First, select a group of representative testers, who can be professional acoustic assessors, rehabilitation assistive device assessors, or long-term users of electric wheelchairs. Then, in a relatively quiet test site with a stable acoustic environment, let the testers ride or approach the electric wheelchair to be tested to simulate different driving scenarios, such as starting, accelerating, driving at a constant speed, turning, climbing, etc. In each scenario, the tester listens carefully to the noise emitted by the wheelchair, and scores and records it according to his subjective feelings. Usually, a scoring system of 1-10 points can be used, and the characteristics of the noise can be described in detail.
Advantages and limitations: The advantage of the subjective evaluation method is that it can directly obtain the real feelings of humans about noise, taking into account the psychological and physiological factors of the user. However, its limitations are also obvious, because subjective evaluation is easily affected by personal differences, emotional state, environmental factors, etc. of the tester, resulting in certain inconsistencies in the evaluation results.
Sound level meter measurement method
Definition: A sound level meter is a commonly used instrument for measuring the loudness of sound. It can accurately measure the decibel value of sound. In the electric wheelchair silent test, the use of a sound level meter can objectively quantify the noise generated by the wheelchair at different positions and distances.
Test process: Place the electric wheelchair on a flat, open test site with low background noise. Select multiple measurement points around the wheelchair, generally including the front, back, sides and near the seat of the wheelchair. The distance of each measurement point can be set according to the actual situation, such as 1 meter, 2 meters from the wheelchair surface, etc. Then, the electric wheelchair is started and operated at different speeds and driving modes, and the decibel value of the noise is recorded at each measurement point using a sound level meter. During the measurement process, it is necessary to ensure that the sound level meter is accurately calibrated and record the environmental conditions at the time, such as temperature and humidity, so as to analyze and compare the measurement results.
Advantages and limitations : The sound level meter measurement method can provide objective and accurate noise data, which is convenient for manufacturers to compare and control the quality of electric wheelchairs of different models and batches. Moreover, as an internationally accepted acoustic indicator, the decibel value is conducive to docking with international standards and regulations. However, this method can only measure the loudness of the sound, and cannot directly reflect the sound quality of the noise and its subjective impact on people. Therefore, it needs to be combined with the subjective evaluation method to comprehensively evaluate the quiet performance of the electric wheelchair.
Noise spectrum analysis method
Definition : The noise spectrum analysis method uses a professional spectrum analysis instrument to decompose the noise generated by the electric wheelchair into different frequency components, so as to gain an in-depth understanding of the spectral characteristics of the noise. Sounds of different frequencies have different effects on human hearing. For example, low-frequency noise may give people a stuffy feeling, while high-frequency noise may be more harsh.
Test process: Use a noise spectrum analyzer to collect and analyze the noise of the electric wheelchair in various driving conditions in real time according to a certain sampling frequency and measurement time. The analyzer converts the noise signal into a spectrum diagram to display the sound pressure level of different frequency components. By analyzing the spectrum diagram, the main frequency range and peak frequency of the noise can be determined, and the key components and causes of the noise can be found, such as the specific frequency noise of the motor, gearbox, tire and other parts.
Advantages and limitations: The noise spectrum analysis method can deeply analyze the inherent characteristics of the noise and provide a detailed basis for the silent design and optimization of the electric wheelchair. Manufacturers can take targeted measures to reduce the noise of specific frequencies based on the results of the spectrum analysis, such as improving the design of the motor, optimizing the gear ratio, and using low-noise tires. However, this method requires professional instruments and technicians with acoustic knowledge to operate and analyze, the test cost is relatively high, and the requirements for the test environment are also relatively strict to ensure the accuracy and reliability of the measurement data.

4. Factors affecting the silent performance of electric wheelchairs and optimization measures
Motor
Impact: The motor is the core power component of the electric wheelchair, and its noise during operation has an important impact on the overall silent performance. During the operation of the brushed motor, the friction between the brush and the commutator will generate sparks and noise, and the noise may gradually increase as the motor wears and ages. In contrast, the brushless motor has a lower noise level and runs more smoothly and quietly because there is no mechanical contact between the brush and the commutator.
Optimization measures: Brushless motors are preferred as the power source of electric wheelchairs. During the design and manufacturing process of the motor, the assembly accuracy of the motor is improved, and the winding structure and magnetic circuit design of the motor are optimized to reduce the electromagnetic noise inside the motor and the noise caused by mechanical vibration. In addition, some motor noise reduction technologies can be used, such as installing motor shock pads and using low-noise bearings, to further reduce the noise transmission during motor operation.
Gearbox
Impact: During the power transmission process of the gearbox, the meshing between the gears will generate noise. If the machining accuracy of the gear is not high, the meshing is poor, or the lubricating oil in the gearbox is insufficient, the gearbox noise will increase, which will affect the quiet performance of the entire electric wheelchair.
Optimization measures: Improve the processing accuracy and assembly quality of the gears, ensure that the gear tooth shape, pitch and other parameters meet the design requirements, and make the gears more stable and smooth during the meshing process. Select suitable gear materials and heat treatment processes to enhance the wear resistance and fatigue resistance of the gears, reduce the wear and deformation of the gears during long-term operation, and thus reduce noise. Regularly check and maintain the gearbox, add or replace lubricating oil in time, maintain a good lubrication state in the gearbox, and reduce friction and impact noise between gears.
Tire
Impact: The rolling noise generated when the tire contacts the ground and the vibration noise of the tire during driving are one of the main sources of noise in electric wheelchairs. Factors such as tire material, pattern design, and air pressure will affect the noise. For example, tires with higher hardness will produce greater rolling noise when driving on rough roads, and tires with too deep or too shallow patterns may also cause noise problems.
Optimization measures: Choose tire materials with good shock absorption performance and low rolling resistance, such as some new environmentally friendly rubber materials or inflatable shock-absorbing tires. Optimize the tire pattern design. Under the premise of ensuring the tire’s grip and drainage performance, minimize the gap between the pattern blocks and the sharpness of the edges to reduce the noise generated when the tire contacts the ground. Ensure that the tire pressure meets the manufacturer’s requirements. Too high or too low pressure will affect the tire’s driving performance and noise level. In addition, you can also consider installing a shock-absorbing pad or using other shock-absorbing devices between the tire and the wheel hub to further absorb the vibration and noise generated by the tire.
Body structure and materials
Impact: The body structure design and materials used in the electric wheelchair will also affect its quiet performance. If the body structure is not strong enough, it is easy to vibrate and make abnormal noises during driving; while the use of some high-density and high-rigidity materials can enhance the strength of the body, but it may increase the weight of the body and increase the noise during driving. On the contrary, if some lightweight materials have poor performance in sound insulation and sound absorption, it will also affect the quiet effect in the car.
Optimization measures: In terms of body structure design, adopt a reasonable frame structure and connection method to increase the rigidity and stability of the body and reduce vibration during driving. Selecting materials with good sound insulation and sound absorption properties to manufacture body parts, such as some new composite materials, foam plastics, etc., can effectively reduce the noise level in the car without significantly increasing the weight of the car body. At the same time, sound insulation strips or sound insulation pads are installed in key parts of the car body, such as the bottom of the seat, the door, the window, etc., to block the introduction of external noise and improve the quiet effect in the car.

5. Development trend of electric wheelchair quiet test equipment and technology
Intelligent test equipment
With the continuous advancement of science and technology, electric wheelchair quiet test equipment is becoming more and more intelligent. Some advanced test equipment can not only automatically collect and analyze noise data, but also automatically evaluate and grade the quiet performance of electric wheelchairs according to preset test standards and procedures. These devices are usually equipped with high-precision sensors, data acquisition systems and intelligent analysis software, which can realize real-time monitoring and online analysis, greatly improving the test efficiency and accuracy.
Virtual simulation technology
The application of virtual simulation technology in electric wheelchair quiet testing has also gradually attracted attention. By establishing a virtual model of the electric wheelchair and using a computer to simulate different driving conditions and noise propagation paths, the quiet performance can be predicted and evaluated in advance during the product design stage. This helps manufacturers to find problems and make optimization improvements in a timely manner during product development, reduce the cost and time of actual testing, and improve the market competitiveness of products.
Multi-physics field coupling analysis
The quiet performance of electric wheelchairs is not only related to acoustic factors, but also coupled with multiple physical fields such as mechanics and thermals. For example, the vibration of the car body will directly affect the generation and propagation of noise, and the heating of the motor may also change its operating state and noise characteristics. Therefore, in the future, the quiet test technology will pay more attention to multi-physics field coupling analysis, comprehensively consider the interaction between various factors, and more comprehensively and accurately evaluate and optimize the quiet performance of electric wheelchairs.

6. Conclusion
The quiet test of electric wheelchairs is an important link to ensure its product quality and user experience. By adopting a variety of quiet test methods, deeply analyzing the factors affecting the quiet performance, and taking corresponding optimization measures, manufacturers can continuously improve the quiet level of electric wheelchairs to meet the needs of wholesale buyers and users in the international market. With the continuous development of testing equipment and technology, the quiet performance of electric wheelchairs will be more effectively evaluated and improved, creating a quieter and more comfortable travel environment for users, and also injecting new vitality into the development of the electric wheelchair industry.