The document describes a high-precision load weight measurement system (WMS) for commercial vehicles. The WMS uses micromechanical sensors to measure the weight of cargo in the vehicle bed with 2.5-3% accuracy. It can provide measurements in all weather conditions. The WMS benefits various stakeholders: it helps manufacturers by monitoring vehicle usage conditions, helps logistics companies track cargo in real-time, and helps authorities efficiently measure weights. The system integrates with an onboard measurement system to further monitor vehicle parameters.

1. HIGH-PRECISION LOAD WEIGHT
MEASUREMENT SYSTEM IN THE VEHICLE
BED
Moscow, 2014

3. High-precision load weight measurement system (WMS) in the vehicle bed is based on
high-precision calibrated micromechanical sensors.
The system allows defining the weight of the load in the vehicle bed when the vehicle stops
within 30 seconds with a high accuracy (about 2.5-3%). High accuracy of weight
measurement is achieved through the use of high-precision micromechanical sensors and
specially developed algorithms for processing the results of measurements in onboard
computer. The developed algorithms take into account the design features of the vehicle
where the WMS is installed.
WMS measurement results are displayed at onboard computer or can be transmitted to the
client via a communication channel.
WMS can operate in all weather conditions as well as under the impact of external factors.
The basic configuration of WMS consists of three measurement sensors, terminal box and
onboard computer with display (if a vehicle has a computer and a data transmission
system, WMS may be connected to them). WMS design may vary individually for specific
customer requirements.
High-precision WMS sensors installed in vandal-proof casing are fixed by “cold welding” on
the load frame of the vehicle without violating its integrity and at the same time providing a
secure fit during vehicle movement on roads with poor road surface.
At the suggestion of the customer an information tank, sensor system and onboard
measurement system (OMS), designed to control the parameters of the vehicle online, may
be integrated into the WMS.
WMS and OMS are developed and protected by RF patents No. 2445586 and No. 113230
respectively.

4. 1. Purpose of high-precision weight measurement system
1. For commercial vehicle manufacturers.
Currently the commercial vehicles have no system that would provide recording of the basic
vehicle operation conditions within a warranty period: the weight of cargo
transported, speed rate, road surface condition, etc. It is well known that improper
operation of vehicles, especially during the warranty period, may lead to technical
malfunctions of the vehicle not through the fault of the manufacturer, but because of
inappropriate operation (overload, driving over the prescribed speed limit with overload on
roads with poor road surface, improperly chosen gear etc.). At the same time commercial
vehicle manufacturers have no real information about the operating conditions of the
vehicles, and so they are forced to perform or carry out warranty repairs or replacement
under warranty on a damaged vehicle. Commercial vehicle manufacturer has to bear
substantial losses due to the lack of WMS in vehicles’ composition, additionally equipped
with OMS.
To solve this problem we propose to install high-precision weight measurement systems
with integrated OMS in series-produced vehicles, which are further connected to the
required sensors (speed, gear, etc.) for the warranty period, as well as to install an
information tank.
The proposed solution will allow determining the weight of the load, which is located in the
vehicle, recording the operating conditions and the condition of the vehicle: its
speed, switched gear, the profile and condition of road surface along which the route of the
vehicle passes, recording impacts on suspension, as well as other service information.
Information recorded in the information tank at the request of the manufacturer can be
transmitted online via the remote monitoring system that will allow tracking vehicle
operation conditions online during the warranty period and identifying the main reasons
leading to the technical malfunction.
2. For leasing companies.
Installation of developed WMS together with OMS on vehicles owned by leasing companies
will also solve the problem faced by the commercial vehicle manufacturers; insure
themselves against unreasonable expenses for repair of vehicles, operated in violation of
the operating conditions, or their replacement by new ones.
In addition, the use of WMS together with OMS and on-board data transmission system
connected online to the dispatch center will allow real-time monitoring of cargo being
transported and vehicle operating conditions, and, if necessary, provide appropriate
guidance to drivers.
3. For state authorities (customs, border service, road service and other Federal Services)
The practical use of the developed WMS will significantly reduce the workload at points of
Customs and Border Federal Services, providing the opportunity to get accurate online
information about the weight of cargo actually

5. transported in the vehicle, and compare the information with the data presented in the
accompanying documentation.
The Federal Road Service, using WMS together with online data transmission system to the
weighing points will allow getting accurate online information about vehicles’ load without
stopping them, which will improve the system of control over the goods being
carried, significantly reduce the workload at weighing points, as well as provide safety of
main transportation routes especially during spring period when restrictions on the passage
of heavy trucks are imposed on separate sections of the roadway.
4. For logistics companies.
Installation of WMS with OMS and onboard data transmission system connected online to
the dispatch centers of logistics companies will allow for remote control of the cargo, will
provide a proper load in accordance with the requirements to vehicles, as well as real-time
control of freight transportation, preventing excess loading and unauthorized unloading of
vehicles. This system will significantly reduce the time of delivery, as the need to pass
multiple weighing on
fixed weighing machines along the route and the loss of time
on waiting for the turn to be weighed will be eliminated. In the long term, after equipping
all vehicles with WMS, stationary weighing points creating inconvenience to other cars on
the routes at the locations of stationary weighing points, will be eliminated.

6. 2. Main advantages of high-precision weight measurement system
The preliminary study of various technical solutions for weighing cargo in the bed of the
vehicle led to the following conclusions:
1. Strain gauge sensor sensitivity is significantly lower than that of sensors based on
micromechanical structures.
2. Strain gauges provide low accuracy (over 15%) of evaluation of load weight in the vehicle
bed and do not solve other problems mentioned in Section 1. Sensors based on
micromechanical structures provide high accuracy (about 2-3%) due to the possibility of
their high-precision calibration, and the use of original algorithms for calculating the weight
of the load according to the results of high-precision measurement of vehicle frame
deflection by three sensors mounted at the optimal points, the coordinates of which are
calculated using specially developed mathematical models.
3. In the weight measurement system based on strain gauges the sensing element is
attached directly to the vehicle body. Therefore, during vehicle operation in adverse
weather conditions the contact of the sensing element with the surface on which it is
installed breaks, which leads first to the loss of precision and then to the loss of data
accuracy. In the developed WMS based on micromechanical sensors the sensitive structure
and the electronic unit for processing measurement results are located inside vandal-proof
sealed enclosure, which is mounted on the frame of the vehicle by “cold welding” not
affecting the integrity of the vehicle load frame.
4. Service life of strain gauges’ sensitive elements is two orders of magnitude less than that
of the sensitive structure of micromechanical sensors.
5. Installation of strain gauges’ sensitive elements requires special preparation of the
vehicle body surface and the use of a special adhesive. Mounting the sensor body on the
basis of sensitive micromechanical structures is carried out using standard technology of
“cold welding”.

7. 3. Weight measurement system based on micromechanical sensitive
structures
A block diagram of WMS based on micromechanical sensitive structures is shown in Fig.
1, and the appearance of WMS sensor, mounted on the frame of the vehicle, is shown in Fig.
2.
Front
tilt gauge
Terminal box
Standard tilt
gauge
Fig. 1
Load weight
information
Front
tilt gauge
Onboard
unit
Fig. 2
The format and procedure for data transmission from sensors to the onboard computer unit
is determined by data communications protocol between the computer unit and the devices
connected to it.
Data communications protocol between the computer unit and the devices connected to it is
provided by the Customer. Data transmission interface is CAN.
The power supply of sensors is provided from the onboard vehicle network via built-in
power source (supply voltage: 9 to 36 V, absorbed current is specified at the stage of delivery
of an experimental batch).
WMS shall be provided with two modes: calibration mode and weight measurement mode.
Before performing weight measurement the system shall be calibrated.
Calibration technique is given in the instruction manual for each vehicle type and can be
adjusted according to the results of preliminary tests.

8. 4. Onboard Measurement System
A block diagram of onboard measurement system (OMS) is shown in Fig. 3 and its
appearance is shown in Fig. 4.
MPU-6000 strapdown
inertial unit
LPC2478
microcontroller
microSD memory
card
SIM908 GPS/GSM
module
USB interface
SIM
card
GPS/GSM
antennas
USB interface
Fig. 3
Fig. 4
Onboard Measurement System (OMS) is designed to control traffic parameters (efficiency
factor) of the vehicle online and is designed for:
• collection of vehicle parameters, their initial processing, long-term
storage,
analysis, and subsequent transfer of the results to a remote centralized
control panel or external storage device;
• determining the actual mileage and operating conditions of the vehicle;
• restoration of vehicle spatial course of movement by recorded data to analyze the
causes of road accidents;
• determining the current location of the vehicle in case of theft.

9. 5. Reliability and service life of WMS and OMS as well as their
resistance to external factors
Mean time between failures of WMS and OMS: at least 17,000 hours (operation mode continuous).
Mean life of WMS and OMS after the completion of preliminary bench tests: at least 15,000
hours.
WMS and OMS characteristics and values of resistance to external mechanical and
environmental factors are shown in Table 1.
Table 1.
10–70
±1
Acceleration amplitude m/s2 (g)
Sinusoidal vibration
Permissible
variation of
test modes
standards
Frequency range, Hz
Exposure factor
Value of
exposure
factor
39.2(4)
±2(0.2)
Characteristics of
exposure factor
Duration of exposure, min
Shock acceleration peak value,
(g)
During operation
90
m/s2
Impact duration, ms
Shock acceleration peak value,
(g)
During transportation
±20%
10
Number of shocks in each direction
Mechanical shocks
147 (15)
m/s2
Impact duration, ms
1000
250 (25)
±20%
6
Number of shocks in each direction
Operating temperature, °С
Reduced temperature
4000
–40
±3
Limiting temperature, °С
–55
±3
Exposure time at each temperature,
h
2
Operating temperature, °С
Elevated temperature
+55
±3
Limiting temperature, °С
+55
±3
Exposure time at each temperature,
h
Relative humidity, %
Humidity at elevated temperature in continuous mode
2
93
±3
Temperature, °С
40
±3
Exposure time at each temperature,
h
144

10. For notes
Moscow, 2014

12. Site: UITech.ch
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