What are the specific steps for testing the brake system of an electric wheelchair?

What are the specific steps for testing the brake system of an electric wheelchair?

1. Preparation before testing

1.1 Check the integrity of the brake system
Before testing the brake system of an electric wheelchair, the brake system must be fully inspected to ensure its integrity. The inspection includes whether the various components of the brake are intact, such as the brake disc, brake pad, brake lever, etc., to ensure that there is no looseness, excessive wear or damage. At the same time, check whether the connection lines and pipes of the brake system are unobstructed and there is no leakage. According to the ISO 7176-3 standard, all components of the brake system must be in good condition to ensure the accuracy and reliability of the test results.

1.2 Confirm the safety of the test environment
The safety of the test environment is crucial. The test site should be a flat, dry, and debris-free ground to ensure that the ground friction coefficient meets the test requirements. According to the GB/T 18029.3-2021 standard, the friction coefficient of the test site should be no less than 0.5 to simulate common road conditions in actual use. In addition, the test site should have enough space for the wheelchair to accelerate, brake and turn to avoid collisions with surrounding obstacles. During the test, obvious warning signs should be set up to ensure the safety of the tester and surrounding personnel.

2. Functional inspection

2.1 Manual operation test
The manual operation test is to test the performance of the electric wheelchair braking system under human intervention.
Operation process: The tester sits on the electric wheelchair and manually operates the brake lever or brake button to feel the sensitivity and strength of the brake. According to the ISO 7176-3 standard, the time from operating the brake device to the start of the wheelchair deceleration should not exceed 0.5 seconds to ensure the timeliness of braking.
Test result evaluation: Record the reaction speed and braking distance of the wheelchair during braking. On a flat and dry road, driving at a speed of 5 km/h, after manual operation of the brake, the braking distance of the indoor electric wheelchair should not exceed 0.5 meters, and the braking distance of the outdoor electric wheelchair should not exceed 0.8 meters.

2.2 Automatic braking function inspection
The automatic braking function is that the electric wheelchair automatically starts the braking system under certain circumstances to ensure the safety of the user.
Slope braking test: Place the electric wheelchair on a 10-degree slope, release the brake, and let the wheelchair slide freely. When the wheelchair speed reaches 3 km/h, the automatic braking system should be activated immediately to stop the wheelchair within 2 meters. This test is carried out in accordance with ISO 7176-10 standard to ensure the safety of the wheelchair on the ramp.
Emergency braking test: When the electric wheelchair is traveling at a speed of 10 km/h, simulate an emergency situation and trigger the automatic braking function. Record the braking distance and braking time. According to GB/T 12996-2023 standard, the emergency braking distance should not exceed 1.5 meters and the braking time should not exceed 1 second.
Parking brake test: After the electric wheelchair stops, start the parking brake function. On a 20-degree slope, the parking brake should ensure that the wheelchair does not slide within 5 minutes. This test refers to ISO 7176-6 standard to verify the reliability of the parking brake.

3. Performance test

3.1 Braking distance measurement
Braking distance is one of the key indicators to measure the performance of the electric wheelchair braking system, which is directly related to the safety of the user. According to the GB/T 18029.3-2021 standard, the specific steps for braking distance measurement are as follows:
Test environment preparation: Select a flat, dry, and debris-free test site to ensure that the ground friction coefficient is not less than 0.5. The test site should have enough straight-line distance for the wheelchair to accelerate and brake.
Test equipment calibration: Use high-precision distance measuring equipment and speed sensors to ensure the accuracy of the measurement data. The accuracy of the distance measuring equipment should reach the millimeter level, and the accuracy of the speed sensor should be not less than 0.1 km/h.
Test process:
Place the electric wheelchair at the test starting point and ensure that it is stationary.
Start the electric wheelchair and make it travel at a constant speed of 5 km/h.
When the wheelchair reaches the specified position, manually or automatically trigger the braking system, and start the timer and distance measuring equipment at the same time.
Record the distance from the start of braking to complete stop of the wheelchair, which is the braking distance.
Data recording and analysis: Repeat the test at least 3 times and take the average value as the final braking distance. According to the standard, the braking distance of indoor electric wheelchairs should not exceed 0.5 meters, and the braking distance of outdoor electric wheelchairs should not exceed 0.8 meters.

3.2 Braking stability evaluation
The braking stability evaluation aims to ensure that the electric wheelchair remains stable during braking to prevent dangerous situations such as rollover and slippage. According to ISO 7176-3 standard, the specific steps of braking stability evaluation are as follows:
Test environment preparation: Select a flat, dry, and debris-free test site to ensure that the ground friction coefficient is not less than 0.5. The test site should have enough space for the wheelchair to perform straight-line braking and turning braking.
Test equipment calibration: Use high-precision inclination sensors and displacement sensors to ensure the accuracy of the measurement data. The accuracy of the inclination sensor should reach 0.1 degrees, and the accuracy of the displacement sensor should not be less than 1 mm.
Linear braking stability test:
Place the electric wheelchair at the test starting point and ensure that it is stationary.
Start the electric wheelchair and make it travel at a constant speed of 10 km/h.
When the wheelchair reaches the specified position, the braking system is triggered manually or automatically, and the inclination sensor and displacement sensor are started at the same time.
Record the inclination change and displacement of the wheelchair during braking to ensure that the wheelchair does not roll over or slip during braking.
Turning brake stability test:
Place the electric wheelchair at the starting point of the test and ensure that it is stationary.
Start the electric wheelchair and make it turn at a speed of 5 km/h with a turning radius of 2 meters.
When the wheelchair reaches the specified position, the braking system is triggered manually or automatically, and the inclination sensor and displacement sensor are started at the same time.
Record the inclination change and displacement of the wheelchair during braking to ensure that the wheelchair does not roll over or slip during turning and braking.
Data recording and analysis: Repeat the test at least 3 times, and record the inclination change and displacement data of each test. According to the standard, the maximum inclination of the wheelchair during braking should not exceed 10 degrees, and the displacement deviation should not exceed 50 mm.

4. Durability test

4.1 Simulated repeated braking
Simulated repeated braking is a key step in evaluating the durability of the electric wheelchair brake system. By simulating the frequent braking scenarios in actual use, the stability and reliability of the brake system in long-term use can be tested.
Test equipment preparation: Use an electric wheelchair brake fatigue tester, such as the ZJ-158 wheelchair parking brake fatigue tester of Dongguan Zhengjie Instrument Co., Ltd. This equipment can simulate the action of repeated manual operation of the brake to ensure the standardization and repeatability of the test process.
Test condition setting: According to GB/T 18029.8-2008 standard, set the test speed to 1-30 times/minute, which is adjustable; set the test number to 1-99999987 times, and the specific number can be adjusted according to actual needs and standard requirements.
Test process:
Fix the electric wheelchair on the brake fatigue tester to ensure that it is in normal working condition.
Start the tester and simulate repeated braking operations according to the set test speed and number. During the test, the performance changes of the braking system are monitored in real time, including key indicators such as braking force and braking distance.
The test is paused at certain intervals (such as 1,000 times), the braking system is checked, and data such as the temperature change of the brake and the wear of components are recorded.
Data recording and analysis: After the test is completed, the collected data is analyzed. Focus on whether the performance of the braking system has significantly decreased with the increase in the number of tests, such as whether the braking force is weakened, whether the braking distance is increased, etc. According to the ISO 7176-8 standard, the performance decline of the braking system after repeated braking tests should be controlled within a certain range to ensure that its durability meets the requirements.

4.2 Checking component wear
Checking component wear is an important part of durability testing. By evaluating the degree of wear of each component of the braking system in long-term use, its service life and reliability can be judged.
Appearance inspection: Perform an appearance inspection on key components such as brake discs, brake pads, and brake rods to check whether there are obvious signs of wear, cracks or deformation. According to ISO 7176-3, the wear depth of the brake disc should not exceed 0.5 mm, and the remaining thickness of the brake pad should not be less than 2 mm, otherwise the parts need to be replaced.
Dimension measurement: Use high-precision measuring tools such as micrometers and calipers to accurately measure the dimensions of the brake system components. Focus on measuring key dimensions such as the thickness of the brake disc, the thickness of the brake pad, and the length of the brake rod. Compare with the initial dimensions and calculate the wear. According to GB/T 12996-2023, the thickness wear of the brake disc should not exceed 10%, and the thickness wear of the brake pad should not exceed 30%.
Performance test: In addition to appearance and dimensional inspection, the brake system needs to be performance tested to evaluate its actual braking effect after long-term use. By simulating actual use scenarios, key indicators such as braking distance and braking force are tested. Compare with the initial performance data to analyze the degree of performance degradation. According to ISO 7176-6, the braking distance should not increase by more than 20% after long-term use, and the braking force should not decrease by more than 15%.
Data recording and analysis: Record the wear and performance test data of each component in detail and establish a durability test database. Through data analysis, evaluate the overall durability of the brake system and determine whether it meets the relevant standard requirements. For components with severe wear, analyze the reasons and propose improvement measures to improve the service life and reliability of the brake system.

5. Environmental adaptability test

5.1 Wet road braking test
The wet road braking test is to evaluate the performance of the electric wheelchair braking system on low friction coefficient roads to ensure that it can still brake safely under bad road conditions.
Test environment preparation: Select or simulate a wet road, such as splashing an appropriate amount of water on the test site to ensure that the ground friction coefficient is between 0.2-0.3. The test site should be flat and without obvious water accumulation to ensure the uniformity of the test conditions.
Test equipment calibration: Use high-precision distance measuring equipment and speed sensors to ensure the accuracy of the measurement data. The accuracy of the distance measuring equipment should reach the millimeter level, and the accuracy of the speed sensor should not be less than 0.1 km/h.
Test process:
Place the electric wheelchair at the test starting point on the wet road and ensure that it is stationary.
Start the electric wheelchair and make it travel at a constant speed of 5 km/h.
When the wheelchair reaches the specified position, manually or automatically trigger the braking system, and start the timer and distance measuring equipment at the same time.
Record the distance from the start of braking to complete stop of the wheelchair, which is the braking distance on wet roads.
Data recording and analysis: Repeat the test at least 3 times and take the average value as the final braking distance on a slippery road. According to ISO 7176-3, the braking distance on a slippery road should not exceed 1.2 meters to ensure that the electric wheelchair still has good braking performance on a low friction coefficient road.

5.2 Slope braking test
The slope braking test is designed to evaluate the braking performance of the electric wheelchair on a slope to ensure its safety when going up and downhill.
Test environment preparation: Select or build slopes with different slopes, such as 10, 15 and 20 degrees. The slope surface should be flat and have a certain friction coefficient to simulate common road conditions in actual use.
Test equipment calibration: Use high-precision distance measuring equipment, speed sensors and inclination sensors to ensure the accuracy of the measurement data. The accuracy of the distance measuring equipment should reach the millimeter level, the accuracy of the speed sensor should not be less than 0.1 km/h, and the accuracy of the inclination sensor should reach 0.1 degrees.
Test process:
Uphill braking test:
Place the electric wheelchair at the bottom of the slope and ensure that it is stationary.
Start the electric wheelchair and make it go uphill at a constant speed of 5 km/h.
When the wheelchair reaches the middle of the slope, manually or automatically trigger the braking system, and start the timer and distance measuring device at the same time.
Record the distance and time of the wheelchair from the start of braking to complete stop.
Downhill braking test:
Place the electric wheelchair at the top of the slope and make sure it is stationary.
Start the electric wheelchair and make it go downhill at a constant speed of 5 km/h.
When the wheelchair reaches the middle of the slope, manually or automatically trigger the braking system, and start the timer and distance measuring device at the same time.
Record the distance and time of the wheelchair from the start of braking to complete stop.
Data recording and analysis: Repeat the test at least 3 times, and take the average value as the final braking distance and time. According to ISO 7176-10 standard, on a 10-degree slope, the braking distance for both uphill and downhill should not exceed 1.5 meters; on a 15-degree slope, the braking distance should not exceed 2 meters; on a 20-degree slope, the braking distance should not exceed 2.5 meters. At the same time, the braking time should not exceed 1.5 seconds to ensure that the braking performance of the electric wheelchair on the slope meets the safety requirements.

6. Emergency Braking Test

6.1 Emergency Braking Response

The emergency braking test is to evaluate the braking response ability of the electric wheelchair in emergency situations to ensure that it can quickly decelerate and stop in a short time to ensure the safety of the user.

Test environment preparation: Select a flat, dry, and debris-free test site to ensure that the ground friction coefficient is not less than 0.5. The test site should have enough straight-line distance for the wheelchair to accelerate and brake.

Test equipment calibration: Use high-precision distance measuring equipment and speed sensors to ensure the accuracy of the measurement data. The accuracy of the distance measuring equipment should reach the millimeter level, and the accuracy of the speed sensor should be not less than 0.1 km/h.

Test process:
Place the electric wheelchair at the test starting point and ensure that it is stationary.

Start the electric wheelchair and make it travel at a constant speed of 10 km/h.

During the wheelchair driving, simulate emergencies (such as sudden obstacles), trigger the emergency braking function manually or automatically, and start the timer and distance measuring equipment at the same time.
Record the time and distance from when the wheelchair triggers the emergency brake to when it stops completely.
Data recording and analysis: Repeat the test at least 3 times and take the average value as the final emergency braking time and distance. According to GB/T 12996-2023 standard, the emergency braking distance should not exceed 1.5 meters and the braking time should not exceed 1 second.

6.2 Stability after emergency braking
The stability test after emergency braking is designed to ensure that the electric wheelchair can remain stable after emergency braking to prevent dangerous situations such as rollover and slippage.
Test environment preparation: Select a flat, dry, and debris-free test site to ensure that the ground friction coefficient is not less than 0.5. The test site should have enough space for the wheelchair to perform straight-line braking and turning braking.
Test equipment calibration: Use high-precision inclination sensors and displacement sensors to ensure the accuracy of the measurement data. The accuracy of the inclination sensor should reach 0.1 degrees, and the accuracy of the displacement sensor should not be less than 1 mm.
Test process:
Place the electric wheelchair at the test starting point and ensure that it is stationary.
Start the electric wheelchair and make it travel at a constant speed of 10 km/h.
During the movement of the wheelchair, the emergency brake function is triggered manually or automatically, and the inclination sensor and displacement sensor are activated at the same time.
Record the inclination change and displacement of the wheelchair after emergency braking to ensure that the wheelchair does not roll over or slip during braking.

7. Data Recording and Analysis

7.1 Recording Test Data
During the test of the electric wheelchair brake system, data recording is a key link to ensure the accuracy and traceability of the test results. The following are the specific steps and requirements for recording test data:
Choose a suitable recording tool: Use professional data recording software or paper recording forms to ensure the completeness and accuracy of data recording. The recording tool should have sufficient space and format to record the parameters and results of each test in detail.
Record test parameters: Before each test, record the parameters of the test environment in detail, including the ground friction coefficient, test site temperature, humidity, etc. At the same time, record the initial state of the wheelchair, such as speed, battery power, etc. According to the GB/T 18029.3-2021 standard, the ground friction coefficient should not be less than 0.5, the test site temperature should be between 15℃-30℃, and the humidity should be controlled between 30%-70% to ensure the consistency of test conditions.
Record test results: During each test, record key data such as braking distance, braking time, inclination change, displacement deviation, etc. in real time. For repeated braking tests, the temperature change and component wear of the brakes after each test should also be recorded. According to the ISO 7176-3 standard, braking distance and braking time are the core indicators for evaluating braking performance, while inclination change and displacement deviation are used to evaluate braking stability.
Data backup and storage: Test data should be backed up in a timely manner and stored in a secure server or cloud storage. The data storage format should be unified to facilitate subsequent data analysis and reference. It is recommended to use CSV or Excel format for data storage to ensure data compatibility and readability.

7.2 Analysis of braking performance
After the data recording is completed, the collected data is analyzed in depth to evaluate the performance of the electric wheelchair braking system. The following are the specific steps and methods for analyzing braking performance:
Data collation and cleaning: Sort the recorded data and remove outliers and duplicate data. Check the integrity and consistency of the data to ensure data quality. For missing data, reasonable estimates or retests should be made based on actual conditions.
Braking distance analysis: Calculate the average and standard deviation of the braking distance for each test to evaluate the stability and consistency of the braking distance. According to the GB/T 18029.3-2021 standard, the braking distance of indoor electric wheelchairs should not exceed 0.5 meters, and the braking distance of outdoor electric wheelchairs should not exceed 0.8 meters. If the braking distance exceeds the standard range, the reasons should be analyzed, such as brake wear, insufficient ground friction coefficient, etc.
Braking time analysis: Calculate the average and standard deviation of the braking time for each test to evaluate the rapidity and stability of the braking time. According to the GB/T 12996-2023 standard, the emergency braking time should not exceed 1 second. If the braking time is too long, the response speed and braking force output of the braking system should be checked.
Braking stability analysis: Evaluate the inclination change and displacement deviation of the wheelchair during braking. According to the ISO 7176-3 standard, the maximum inclination angle of the wheelchair during braking should not exceed 10 degrees, and the displacement deviation should not exceed 50 mm. If the braking stability does not meet the standard, it may be related to the center of gravity distribution of the wheelchair and the design of the braking system, which needs further optimization.
Durability analysis: For the data of repeated braking tests, analyze the performance changes of the braking system after multiple braking. According to ISO 7176-8, after repeated braking tests, the performance degradation of the braking system should be controlled within a certain range, such as a braking force reduction of no more than 15% and a braking distance increase of no more than 20%. If the performance degradation is obvious, the material and structure of the brake should be checked and improvement measures should be proposed.
Environmental adaptability analysis: For the data of wet and slippery road and slope braking tests, analyze the performance of the braking system under different environmental conditions. According to ISO 7176-3, the braking distance on wet and slippery roads should not exceed 1.2 meters; according to ISO 7176-10, on slopes of different slopes, the braking distance and time should meet the corresponding safety requirements. If the braking performance does not meet the standard under specific conditions, consider adding anti-skid devices or optimizing the design of the braking system.