An auxiliary device for radio frequency electromagnetic field immunity test of electric wheelchair

Abstract

The application discloses a kind of technical solutions, provide a kind of auxiliary device for electric wheelchair radio frequency electromagnetic field immunity test, it is characterized in that, including for fixing the front wheel of electric wheelchair and for carrying the front wheel weight front wheel carrying unit and for installing electric wheelchair rear wheel rear wheel position fixed unit.Another technical solution of the application is to provide a kind of application of the above-mentioned auxiliary device for electric wheelchair radio frequency electromagnetic field immunity test.The application can be applicable to different specifications of electric wheelchair;Rear drive wheel fixed unit can be adjusted according to the actual size of electric wheelchair;Rear drive wheel is equipped with rear drive wheel fixed unit respectively, eliminates the potential safety hazard that wheel speed difference can cause;It is convenient to monitor wheel speed and differential in test;The influence of the device on radio frequency electromagnetic field uniformity is small, and the increment of radio frequency electromagnetic field uniformity index in the uniform plane caused by the device within 80MHz-2.5GHz is less than 1dB;The influence of the device on radio frequency electromagnetic field is small.

Description

Technical Field

[0001] This invention relates to an auxiliary device for testing the radio frequency electromagnetic field immunity of electric wheelchairs, belonging to the field of electromagnetic compatibility. Background Technology

[0002] The purpose of electromagnetic compatibility (EMC) testing is to assess whether systems and equipment can operate normally and without interference in a specific electromagnetic environment. Radio frequency (RF) electromagnetic field immunity testing is one of the key EMC tests, primarily assessing whether equipment can meet expected operational and safety requirements under specific electromagnetic field strength conditions within a certain frequency range. Technical details are mainly specified using GB / T 17626.3-2016. GB / T 17626.3-2016 specifies that the uniform field strength surface of the test area is a 1.5m x 1.5m vertical uniform surface with a horizontal line 0.8m above the ground as the lower baseline, located 3m vertically from the antenna reference point. The allowable range for field strength deviation within the uniform electromagnetic field area is 0 to +6dB, with typical verification results between +3.0 and +4.5dB. Any auxiliary devices placed in the test area will affect the uniformity of the electromagnetic field strength through effects such as reflection and absorption of electromagnetic waves (especially widely used metal support structures), thus leading to deviations in the test results. The core controller unit of an electric wheelchair is located under the seat, making it more susceptible to electromagnetic wave reflections from the supporting structure. To improve the accuracy of the detection data, it is necessary to minimize the reflection of electromagnetic waves by the support device and reduce its impact on the uniformity of the electromagnetic field.

[0003] GB / T 18029.21-2012 specifies that in the radio frequency electromagnetic field test of electric wheelchairs, the electric wheelchair must be placed in the electromagnetic field test area and in normal operating condition, with real-time monitoring of wheel speed changes and differential speed. The test frequency is 26MHz-2500MHz. The weight of the electric wheelchairs ranges from approximately 20 kg to over 100 kg. The test lacks structurally reliable and electromagnetically insensitive auxiliary support devices. All actions of the electric wheelchair (such as starting, stopping, steering, and emergency stopping) are executed by the controller. External interference to the controller (electromagnetic interference or vibration, etc.) can cause malfunctions, failures, or even accidents. The test requires separate monitoring of the rotational speed and wheel speed deviation of the rear drive wheels. To improve the safety of auxiliary equipment operation and improve wheel speed monitoring measures, the rear wheels need to be equipped with independent passive load-bearing transmission units. Therefore, reducing the influence of electric wheelchair auxiliary devices on the electromagnetic field, improving the safety of auxiliary equipment operation, and improving wheel speed monitoring measures are essential to achieving the goal of reducing deviations in the radio frequency electromagnetic field immunity test of electric wheelchairs. Summary of the Invention

[0004] The purpose of this invention is to provide an auxiliary device for testing the radio frequency electromagnetic field of an electric wheelchair, which has less impact on the uniformity of the radio frequency electromagnetic field, is safer and more convenient to operate, and has more comprehensive monitoring measures.

[0005] To achieve the above objectives, the technical solution of the present invention provides an auxiliary device for radio frequency electromagnetic field immunity testing of electric wheelchairs, characterized in that it includes a front wheel bearing unit for fixing the front wheels of the electric wheelchair and bearing the weight of the front wheels, and a rear wheel position fixing unit for mounting the rear wheels of the electric wheelchair, wherein:

[0006] The front wheel bearing unit is equipped with a front wheel position fixing unit for mounting the front wheel of the electric wheelchair and preventing the front wheel from slipping;

[0007] The rear wheel position fixing unit further includes:

[0008] Two sets of rear drive wheel fixing units, each set of rear drive wheel fixing units is used to lock the left or right rear drive wheel of the electric wheelchair from the front;

[0009] Two sets of rear drive wheel fixing units II, each set of rear drive wheel fixing units II is used to lock the left or right rear drive wheel of the electric wheelchair from the rear;

[0010] Two sets of rear drive wheel support units, each set of rear drive wheel support units is used to support the left or right rear drive wheel of the electric wheelchair;

[0011] Two sets of rear drive wheel fixing units are respectively connected to the front wheel bearing unit and the two sets of rear drive wheel bearing units;

[0012] Two sets of rear drive wheel bearing units are connected to two sets of rear drive wheel fixing units.

[0013] Each rear drive wheel bearing unit is equipped with a wheel speed sensor access channel. The wheel speed sensor can monitor the wheel speed in real time after being connected through this wheel speed sensor access channel.

[0014] Preferably, the cross section between the front wheel bearing unit and the rear drive wheel fixing unit is an adjustable telescopic cross section to accommodate the front and rear wheelbases of different electric wheelchairs.

[0015] Preferably, the cross section between the rear drive wheel fixing unit one and the rear drive wheel bearing unit one is a telescopic cross section two with adjustable spacing;

[0016] The cross section between the rear drive wheel fixing unit 2 and the rear drive wheel bearing unit 1 is a telescopic cross section 3 with adjustable spacing;

[0017] The size of the rear wheel position fixing unit can be adjusted by adjusting the telescopic section two and the telescopic section three to suit different wheel hub specifications.

[0018] Preferably, the front wheel position fixing unit is a trapezoidal groove provided on the front wheel bearing unit.

[0019] Preferably, fixing straps are used at the front and rear of the front wheel position fixing unit, so that the front wheel of the electric wheelchair is tangent to the plane of the front wheel position fixing unit.

[0020] Another technical solution of the present invention is to provide an application of the above-mentioned auxiliary device for radio frequency electromagnetic field immunity testing of electric wheelchairs, characterized in that the above-mentioned auxiliary device carrying the electric wheelchair is placed on a test bench, the test surface of the electric wheelchair is placed in the electromagnetic field uniform surface, and a wave-absorbing material is provided between the test bench and the radiating antenna for generating the electromagnetic field.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1) The front and rear wheelbases are adjustable, making it suitable for electric wheelchairs of different sizes;

[0023] 2) The rear drive wheel fixing unit can be adjusted according to the actual size of the electric wheelchair;

[0024] 3) Each rear drive wheel is equipped with a rear drive wheel fixing unit, eliminating potential safety hazards caused by wheel speed differences;

[0025] 4) It integrates a wheel speed sensor access channel, which facilitates the monitoring of wheel speed and differential speed during the test;

[0026] 5) The device has little impact on the uniformity of the radio frequency electromagnetic field, and causes an increase of less than 1dB in the in-surface uniformity index of the radio frequency electromagnetic field within the range of 80MHz-2.5GHz.

[0027] 6) The device has little impact on radio frequency electromagnetic fields, and the voltage standing wave increment of the detection system caused in the frequency range of 80MHz-2.5GHz is less than 1. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of an electromagnetic compatibility testing device for an electric wheelchair.

[0029] Figure 2 This is a schematic diagram of the device's wheelbase adjustment.

[0030] Figure 3 This is a diagram showing the wheel positions of an electric wheelchair.

[0031] Figure 4 This is a schematic diagram of the device's application.

[0032] Figure 5 This is a schematic diagram of the radio frequency electromagnetic field immunity test for an electric wheelchair. Detailed Implementation

[0033] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0034] This embodiment discloses an auxiliary device for testing the radio frequency electromagnetic field immunity of a wheelchair, including a front wheel (swivel wheel) support unit 1, a front wheel (swivel wheel) position fixing unit 2, a rear wheel position fixing unit 3, a rear drive wheel fixing unit one (two sets) 4, a rear drive wheel support unit one (two sets) 5, a rear drive wheel fixing unit two (two sets) 6, a wheel speed sensor access channel D, and three cross-sectional positions AA'A”, BB'B”, and CC'C” that can be adjusted in size.

[0035] This invention uses a front wheel (swivel wheel) support unit 1 to fix the front wheel of an electric wheelchair and bear its weight. The front wheel (swivel wheel) support unit 1 is equipped with a front wheel (swivel wheel) position fixing unit 2, which is firmly connected to the front wheel (swivel wheel) support unit 1 and is used to install the front wheel (swivel wheel) of the electric wheelchair and prevent it from slipping. Preferably, fixing straps are used at the front and rear of the front wheel (swivel wheel) position fixing unit 2, so that the front wheel is tangentially tangent to the plane of the front wheel (swivel wheel) position fixing unit 2.

[0036] The rear wheel position fixing unit 3 is used to install the rear wheels of an electric wheelchair and prevent the front wheels from sliding. It includes two sets of rear drive wheel fixing units one 4, rear drive wheel bearing units one 5, and rear drive wheel fixing units two 6. The rear drive wheel fixing units one 4 are respectively connected to the front wheel (universal wheel) bearing unit 1 and the rear drive wheel bearing units one 5, and the rear drive wheel fixing units two 6 are connected to the rear drive wheel bearing units one 5. One set of rear drive wheel fixing units one 4, rear drive wheel bearing units one 5, and rear drive wheel fixing units two 6 are used to independently bear the support and passive driving functions of the left rear wheel, and the other set of rear drive wheel fixing units one 4, rear drive wheel bearing units one 5, and rear drive wheel fixing units two 6 are used to independently bear the support and passive driving functions of the right rear wheel, meeting the operation requirements of the electric wheelchair. The rear drive wheel fixing units one 4 and the rear drive wheel fixing units two 6 are used to fix the left rear wheel or the right rear wheel in the front-back direction, serving as passive wheel units, achieving the front and rear clamping of the rear drive wheels of the electric wheelchair, and preventing safety risks such as slipping, deviation, and emergency steering caused by wheel speed differences. The rear drive wheel bearing units one 5 are used to bear the weight of the left rear wheel or the right rear wheel load.

[0037] The wheelbase can be adjusted at the three cross-sections of AA’A”, BB’B”, and CC’C”. Among them, the adjustment of the cross-section position AA’A” is mainly based on the front-back wheelbase of the wheelchair, and BB’B” and CC’C” mainly adjust the spacing to adapt to the size of the rear wheels.

[0038] The wheelbase adjustment of the three cross-sections of AA’A”, BB’B”, and CC’C” can be achieved by using conventional structures well-known to those skilled in the art. In this embodiment, the specific structures for achieving the wheelbase adjustment of the three cross-sections of AA’A”, BB’B”, and CC’C” Figure 2 , according to the front-back wheelbase of the electric wheelchair, adjust the internal connecting pins at the cross-sections of AA’A”, BB’B”, and CC’C” to achieve the adjustment of the front-back wheelbase. At the same time, insert a single or multiple insertion block combinations with a thickness of 5 mm - 10 cm at the cross-section. The insertion blocks have the same size as the cross-section of the device, and the connection with the internal connecting pins of the device is a U-shaped groove structure from bottom to top, facilitating insertion from top to bottom into the three cross-sections of AA’A”, BB’B”, and CC’C” for wheelbase adjustment. At the external connection of the device, a flexible connection fastening belt is used for connection to ensure the stability of the device structure. When applied to an electric wheelchair with a weight of more than 100 kg, preferably, a flexible connection fixing belt can be added around the vertical plane outside the device.

[0039] See Figure 3 , the front and rear wheels of the electric wheelchair are respectively placed on the auxiliary device. The left front wheel and the right front wheel are placed in the front wheel (universal wheel) bearing unit 1, and by adjusting the cross-section position AA’A”, the left rear wheel and the right rear wheel are placed in the rear wheel position fixing unit 3. See Figure 3 and Figure 4 By adjusting the cross-sectional positions BB'B” and CC'C”, the left rear wheel, right rear wheel, support wheel, and driven wheel are respectively brought into contact to prevent slippage.

[0040] Between the two rear drive wheel bearing units 5 is the wheel speed sensor access channel D, which is used to connect the wheel speed sensor to realize real-time wheel speed monitoring. The position can be adjusted within a certain range to adapt to different wheel spacing.

[0041] The dielectric constant of the base, rolling shaft, connecting parts, etc. of the front wheel (universal wheel) bearing unit 1, rear drive wheel fixing unit 1 4, rear drive wheel bearing unit 1 5 and rear drive wheel fixing unit 2 6 is <1.4.

[0042] The aforementioned device, placed within a uniform surface of the test area, causes less than 1 dB of field uniformity increment and less than 1 dB of field voltage standing wave increment within the frequency range of 80 MHz to 2500 MHz, thereby achieving stable operation of the electric wheelchair and minimizing its impact on the test. (See reference...) Figure 5 The auxiliary device and wheelchair were placed on a test platform with a height of 0.8m. The test surface of the electric wheelchair was placed in a uniform electromagnetic field, and the antenna reference point was 3m away.

[0043] A preferred embodiment is to fix two sets of safety belts (one set for each of the left and right wheel positions, with one belt on each of the left and right sides of each wheel) on the left and right sides of the front wheel (swivel wheel) support unit 1, respectively, to fix the front wheel of the electric wheelchair placed at the front wheel (swivel wheel) position fixing unit 2, keep the wheels and the electric wheelchair facing the same direction, and prevent the electric wheelchair from swaying back and forth.

[0044] Example 2

[0045] refer to Figure 5 Remove the auxiliary device and wheelchair from the test bench and conduct the test at a test level of 20V / m, recording the voltage standing wave of the detection system. (Reference) Figure 5 The auxiliary device of this invention was placed on a 0.8m test bench and tested at a test level of 20V / m. The voltage standing wave of the detection system was recorded. The difference between the two values ​​was compared and found to be less than 1.

Claims

1. An auxiliary device for testing the radio frequency electromagnetic field immunity of an electric wheelchair, characterized in that, It includes a front wheel support unit for securing the front wheels of an electric wheelchair and bearing their weight, and a rear wheel positioning unit for mounting the rear wheels of the electric wheelchair, wherein: The front wheel bearing unit is equipped with a front wheel position fixing unit for mounting the front wheel of the electric wheelchair and preventing the front wheel from slipping; The rear wheel position fixing unit further includes: Two sets of rear drive wheel fixing units, each set of rear drive wheel fixing units is used to lock the left or right rear drive wheel of the electric wheelchair from the front; Two sets of rear drive wheel fixing units II, each set of rear drive wheel fixing units II is used to lock the left or right rear drive wheel of the electric wheelchair from the rear; Two sets of rear drive wheel support units, each set of rear drive wheel support units is used to support the left or right rear drive wheel of the electric wheelchair; Two sets of rear drive wheel fixing units are respectively connected to the front wheel bearing unit and the two sets of rear drive wheel bearing units; Two sets of rear drive wheel bearing units are connected to two sets of rear drive wheel fixing units. Each rear drive wheel bearing unit is equipped with a wheel speed sensor access channel. The wheel speed sensor can be connected through this wheel speed sensor access channel to realize real-time monitoring of wheel speed. The cross section between the front wheel bearing unit and the rear drive wheel fixing unit is an adjustable telescopic cross section to accommodate the front and rear wheelbases of different electric wheelchairs. The cross section between the rear drive wheel fixing unit one and the rear drive wheel bearing unit one is a telescopic cross section two with adjustable spacing; The cross section between the rear drive wheel fixing unit 2 and the rear drive wheel bearing unit 1 is a telescopic cross section 3 with adjustable spacing; The size of the rear wheel position fixing unit can be adjusted by adjusting the telescopic section two and the telescopic section three to suit different wheel hub specifications.

2. The auxiliary device for radio frequency electromagnetic field immunity testing of electric wheelchairs as described in claim 1, characterized in that, The front wheel position fixing unit is a trapezoidal groove provided on the front wheel bearing unit.

3. The auxiliary device for radio frequency electromagnetic field immunity testing of electric wheelchairs as described in claim 1, characterized in that, Fixing straps are used at the front and rear of the front wheel position fixing unit so that the front wheel of the electric wheelchair is tangent to the plane of the front wheel position fixing unit.

4. The application of the auxiliary device for radio frequency electromagnetic field immunity testing of electric wheelchairs as described in claim 1, characterized in that, The auxiliary device as described in claim 1, carrying an electric wheelchair, is placed on a test bench. The test surface of the electric wheelchair is placed within a uniform electromagnetic field surface. An absorbing material is provided between the test bench and the radiating antenna used to generate the electromagnetic field.

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