HOW INNOVATIVE SENSORS ARE REVOLUTIONIZING TORQUE AND FORCE MEASUREMENT
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HOW INNOVATIVE SENSORS ARE REVOLUTIONIZING
TORQUE AND FORCE MEASUREMENT
1
Content
1 THE CHALLENGE OF
ELEC TRIC MOBILIT Y
5 TR AINS
Safety in breaking 14
systems
Electric torque vectors 04
systems
2 ELEC TRIC C ARS 6 OUR SENSORS
Comfort and driving 06 Torque sensor 16
Steering systems 08 Force sensor 17
3 E-BIKES 7 CONCLUSION
Drive control 10 20
4 TRUCK S
Safety and efficiency 12
02 TORQUE AND FORCE SENSORS IN E- MOBILIT Y
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In almost all new cars there are power steering
• Youtube
systems that support the driver's ride. This makes them
important for driving comfort using a torque system
that determines the force applied to the steering wheel.
14 E-BIKE 18 TORQUE SENSORS
The intelligence of the
Here is a preview of The demanding driving
sensors has changed a
highlights from the fields of control of an e-bike
lot in the last 20 years.
steering systems, e-bikes is a great challenge.
In the beginning, the
and torque sensors.
main benefit of a sensor
was the conversion of
a physical amount into
an electrical signal.
TORQUE AND FORCE SENSORS IN E- MOBILIT Y 03
01
The challenge of E-mobility
E-Mobility covers a wide spectrum of topics, from electrification of motorcycles
to autonomous driving. The efficient operation of the engine of today's electric
or railway vehicles requires permanent monitoring and diagnosis of the engines
by means of intelligent sensors. In the future, the demands on sensors in terms of
measurement ranges and dynamics will increase significantly, due to technological
advances in power electronics. Today, sensor manufacturers focus heavily
on equipping vehicles with intelligence so that they can drive autonomously.
Less attention is being paid to drive efficiency and dynamic driving comfort.
Significant progress could be made with small, intelligent sensor solutions.
A major difference between means movement, in the electric motor this
of transport based on conventional impulse is instantaneous. The danger
internal combustion engines and of sudden acceleration when the wheel
electronic mobility vehicles is the way in loses contact with the asphalt in a curve
which the necessary torque is applied, is much greater in the electric motor than
which is ultimately responsible for the in the combustion engine. Measuring
actual locomotion. While the torque of pairs and their need for efficient and
an internal combustion engine depends dynamic motion is an aspect of sensor
on the range of engine speeds and the technology for electronic mobility.
speed of the turbocharger, the torque Another aspect revolves around
of an electric motor is available instanta- dynamics and driving comfort. Force
neously. This brings some advantages, and torque sensors are also used
for example, the driver of an electric in vehicle dynamics applications.
car can accelerate in a very short time, For example, the torque sensors in
but there are also dangers. In the field wank stabilizers can determine the
of e-Mobility, there are situations that position of the vehicle and intervene
have never occurred before with the by control to increase driving comfort.
combustion engine. One of these Electric mobility is also often associated
scenarios is to stop and accelerate with autonomous driving. For
in a curve. While in the combustion autonomous driving, the number of
engine it is necessary to generate a sensors used increases exponentially.
previous rotation movement, which is The trend in steering systems is
initially small, to generate the impulse clearly in the direction of "Steered
04 TORQUE AND FORCE SENSORS IN E- MOBILIT Y
"With electric torque
vector systems...
the engine torque is
specifically transmitted to
the individual wheels..."
by Wire", also to prepare the car for
them, the drive torques are specifically
use in autonomous vehicles. With
transmitted to the individual wheels in
"Steered by Wire" steering systems, the
order to be able to actively steer the
steering column is no longer directly
vehicle. This is done by correcting the
connected to the steering shaft and
angle of rotation around the vertical axis.
the signals transmitted from the driver
The driver gets an improved and more
to the steering wheel are recorded
natural driving experience. This actively
electronically (e.g. with a non-contact
prevents the vehicle from understeering
torque sensor) and the steering angle
or oversteering. Especially in electric
of the vehicle is adjusted on the basis of
vehicles that do not have a cardan shaft,
this information.
the driving torque can be controlled by
several electric motors.
Another use is real-time axle load
measurement for trucks. A new
The possibilities in sensors for electric
guideline requires that, in the future,
mobility applications are very wide.
a police officer be able to detect an
The emergence of new application
overload on a truck through a weighing
possibilities and new standards are
device that would carry the truck on
the driving force behind innovation in
board. This weighing device can be
this field. Magnetic Sense's magnetic-
implemented by means of force sensors
inductive force sensors are designed
on the axles of the truck. A connected
to meet these new requirements.
load management system can also be
used to determine the centre of gravity
of the load and issue a warning in case
of danger.
Improving steering behaviour with
E-Torque vectoring
With the electric torque vector systems
and the new torque sensors contained in
TORQUE AND FORCE SENSORS IN E- MOBILIT Y 05
02
Electric cars
Comfort and driving
An increasing demand for torque motor. These bi-directional force
information is needed not only in internal flows must be measured, monitored
combustion engines for map control, and evaluated in the functional
but also in electric vehicles. On the one safety circuits in serial applications.
hand, the torque is the power factor of With a torque sensor that can measure
the vehicle, but on the other hand it is the force directly on the drive shaft, it
also a decisive factor for driving comfort. is possible to collect this safety-rel-
evant information and transmit it to
the controller. This is still easy when
electric motors are used for the entire
In electric car drives, the power of vehicle. When wheel drives are used,
the electric motor will in future be it becomes more difficult. Each wheel
connected almost directly to the drive drive has its own performance behavior,
shaft. Therefore, in many cases there is which can be calibrated to each other,
no or only a very rudimentary gearbox but can be misaligned by aging effects.
in the middle. This direct connection The adjustment of these electric motors
results in an electric torque that acts determines the driving behaviour of the
directly on the drive shaft, i.e. a direct vehicle. Without a direct measurement
power flow. This direct power flow of the parameters at the output of the
must be taken into account in the safety electric motor, it is almost impossible
aspects. A failure of the electric motor to determine the driving behaviour
or unwanted output power has a direct of the vehicle. With the use of torque
effect on the driving behaviour of the sensors in these electric motors, the
vehicle. It is therefore necessary to install behaviour of each individual electric
many additional sensors for series use in motor can be measured instantly and
order to intercept or plausilize faults and used as a nominal value input in the
initiate appropriate emergency stops. control unit to control the motors.
Not only from the electric motor to the Not only the direct drive, but also the
drive, but also the effects of road force driving comfort can be improved by
have a direct effect on the electric means of force sensors. For example,
06 TORQUE AND FORCE SENSORS IN E- MOBILIT Y
torque sensors in the limited slip additional load has been absorbed. This
differential can be used to precisely information is important for determining
adjust the torque in the individual fuel consumption or as an input variable
wheel, resulting in optimum cornering for the acceleration and deceleration
performance for the car. The information behaviour of the vehicle. There are other
required for torque vectorisation can possible applications in the steering
not only improve driving dynamics. area for measuring steering forces.
In principle, they can also be used
to measure wheel slip and serve as a
control variable for anti-slip control.
In addition to these classic applications
for torque sensors, there are other fields
of application in the field of electric
mobility. For example, sensors can be
used to directly measure the weight of
the vehicle and determine how much
"With a torque
sensor (...) it is
possible to collect
this safety-relevant
information."
TORQUE AND FORCE SENSORS IN E- MOBILIT Y 07
02
Electric cars
Steering systems
Car steering systems consist of a large transmitted from the driver to the steering
number of subsystems, which together wheel are recorded electronically and
form a well-coordinated unit. Almost all the vehicle steering angle is adjusted
new cars have power steering systems on the basis of this information.
that support the steering power of the
driver and are therefore relevant to The trend of these systems shows the
steering comfort. To determine this need for good integration between the
force applied to the steering wheel, sensor systems, which are necessary
there is a torque system that registers to pick up the driver's signals. It is
the torques directly in the steering also necessary to record an overlay
and acts as a control variable for of driver signals with force feedback.
hydraulic or electric steering assistance. Force feedback is necessary because
the driver needs haptic feedback when
The existing torque shafts in the steering the handlebar is no longer connected
systems are designed to meet the highest and there is no torsion in the steering
safety requirements. Some of today's column. Conventional torque sensors
systems have been in use for years and are not suitable for these applications,
are based on established technologies. new solutions need to be created.
The trend in steering systems is clearly
in the direction of "Steered by Wire".
This is mainly due to the fact that future
generations of cars must be prepared
for autonomous driving. In "Steered by
Wire" steering systems, the steering
column is no longer directly connected
to the steering shaft. This means that
in these steering systems the signals
08 TORQUE AND FORCE SENSORS IN E- MOBILIT Y
"...Measure the
torque of the
non-contact
steering column
in the smallest
possible space."
Magnetic Sense's new technology
for the development of magnetic-in-
ductive torque sensors opens up new
application possibilities in this field. Our
sensors can be dimensioned in such a
way that they can even be integrated
into tight spaces to measure the steering Other applications are also emerging
column torque without making contact. in the agricultural sector, with fully
Its technology allows redundant automatic harvesting machines.
signal processing and, depending Non-contact torque measurement
on application requirements, can be can be used in all applications
used in safety-relevant applications. where motors move machines.
TORQUE AND FORCE SENSORS IN E- MOBILIT Y 09
03
E-Bike
Drive control
Bicycles with electric motor to support Until now, applications of torque
the driver are becoming increasingly sensors have been limited. The
popular among various consumer introduction of the magnetoelastic
groups. Sales of e-bikes in Germany have torque sensor opens up completely
doubled in 5 years until 2016. Bicycles new areas, such as e-Mobility.
of this type can not only withstand the
pedalling power of the cyclist, but also Magnetoelastic torque and force
allow higher speeds. These properties sensors, such as those manufactured
require reliable torque measurement. by Magnetic Sense, measures changes
in the electrical inductance and
convert these data into measurement
The driving control of an e-Bike is a results. This gives a great advantage to
great challenge. On the one hand, the non-contact torque measurement and
drive unit must support the rider when there are more and more fields where it
necessary and, on the other, it must be is possible to apply these sensors. This is
switched off as soon as the driver no also the case for applications in electric
longer needs the support. Therefore, mobility and, in this specific case, in
the transition between human pedal the motors of e-Bikes. Torque sensors
force and engine power must be can be mounted on the rear axle, on
smooth, so that people and the bicycle the drive unit or on the pedal axle.
form one unit. To do these, simple
sensors are not enough. The torque
released by the driver's pedaling force
must be determined by other means.
Torque sensors have the necessary
conditions to solve this problem.
010 TORQUE AND FORCE SENSORS IN E- MOBILIT YThe e-Bike sensor can pick up the torque as on pedals. In addition, the torque
accurately and without contact. As soon sensor can be used in a temperature
as the pilot steps on the pedals, the range of -40 °C to 85 °C and operates
forces act on the shaft and the magnetic with high measurement accuracy. This
field of this ferromagnetic material means that the torque sensor not only
changes. These changes are recorded guarantees non-contact measurement,
by the torque sensor and transmitted but also precise measurement
to the sensor electronics for evaluation. results under difficult conditions.
The Magnetic Sense's sensor can also
measure torque at low speeds, such
" The Magnetic
Sense's sensor
can also measure
torque at low
speeds (...)."
TORQUE AND FORCE SENSORS IN E- MOBILIT Y 01104
Trucks
Safety and efficiency
Time is money and that applies to In addition to these electric mobility
many services. But, above all, also in systems, there are also requirements
the transport sector. The pressure of for sensors in the truck of the future.
time and costs are external factors that For example, in addition to functional
define the future of the freight transport safety in the drive, load monitoring
sector on the railways, in the air, in the and overload protection must also be
water and on the road. The greatest developed. The motors of the future
factor of uncertainty in this interaction will be electric motors. The electric
is the state of operation of the machine motors available on the market today
and the people needed to operate it. are designed in such a way that many
interference sensors are required to
control the drive unit and thus guarantee
its functional safety. Direct control of the
The truck of the future can drive very
drive torques of truck engines (electric
efficiently and quickly from A to B and
motors and combustion engines) would
dispatchers have all the information
allow many additional systems to be
about the operating status and loading
dispensed with. Torque sensors directly
of the vehicle at all times. This is the
on the output drive can also help to
vision of many transport companies
improve the efficiency of the entire
and drivers of innovation in this field.
system and thus save energy. Torque
Sensor manufacturers are needed
sensors on the wheels or drive unit
to turn these visions into reality. The
directly in combination with an absolute
autonomous driving of cars is still in its
angular signal are also able to detect
infancy. In the case of trucks, this step
tyre slippage, allowing the control
is not far off either. Electric mobility
system to react directly to such events.
and associated autonomous drives
and steering systems are already being
tested by many original equipment
manufacturers on the road. The
market for sensors for driver assistance
systems is very competitive and is
the focus of many strategic meetings.
012 TORQUE AND FORCE SENSORS IN E- MOBILIT Y"Engines from the
future are electric"
In addition to torque sensors, force Many other possible applications
sensors are also increasingly popular for force sensors in trucks will
in the truck sector. Truck axle load enable more innovations and sensor
sensors can not only detect whether concepts in the coming years for the
the truck is overloaded or within the solution of tomorrow's applications.
normal range, they can also detect
when the truck has been loaded or
unloaded. This allows shippers to
monitor their trucks online and use the
received data for plausibility checks.
EU regulatory laws even oblige truck
manufacturers to implement such
systems on the truck to inform the
police of the direct loading status of
the truck during an inspection. This is to
prevent truck overloading from causing
traffic accidents or damage to the road.
TORQUE AND FORCE SENSORS IN E- MOBILIT Y 01305
Trains
Safety in braking systems
The train is considered one of the count how many people have boarded
safest and most comfortable travel or exited the train. If you are interested
options today. It is common for a railway in this topic, you can read our article
engineer and his suppliers to deal on a on sensors in electric cars where these
daily basis with sensors for operation topics of safety and comfort while
and safety, since in recent decades, it driving are discussed. Force sensors
has undergone significant development can also determine the weight of the
in terms of safety and efficiency. load on the axle of the wagon and
how it changes during loading. This is
Sensors in braking systems can measure especially interesting in freight transport,
the axle load and regulate the braking where the transport cost is calculated
force accordingly. Railway braking from the weight of the load and the
systems are divided into several stages. volume. In this way, the rail operator
From light braking to actual stop, can check the data of his customers.
there are several systems that support
each other. A few decades ago, it was Force transducers are also used in the
common for passengers to have to field of pantograph axis transducers.
hold on to each other in order not to The contact force of the pantograph
fall, but this went down in history when with the overhead contact line defines
multi-stage braking systems came the quality of the electrical connection.
into being. Force or torque sensors If it is too weak, it is possible that the
installed on the brakes or wheel axles electrical contact resistors are too
can measure the forces acting on the high and that a drop in power occurs.
mechanics during the braking process
and regulate the braking force according
to these forces. In this way, closed-loop
brake controls can be implemented.In
addition to the control of the braking
force, sensors are also used in the field
of load management. For example,
force sensors in the boarding area can
014 TORQUE AND FORCE SENSORS IN E- MOBILIT YIf the load is too high, axles have passed through a point. This
malfunctions may occur. information can be used, for example,
High forces and loads also occur in to make emergency stops in the event
the area of the couplings in trains. The of a wagon stopping to avoid a collision.
force transducers in these positions Some of these sensors are based on
can determine the train loads and issue optical and ultrasonic technologies. By
a warning in the event of overload integrating force sensors into the rails,
or unintentional disconnection. the signal quality and reliability of this
measurement method can be improved.
Thanks to the technology of magneto-
There are many possible applications
inductive force sensors, which can be
for torque and force sensors in the
easily integrated at any measurement
railway sector. The integration of
point, these measurement methods can
sensors into the railway infrastructure
be adapted to existing track sections.
is also an exciting topic. There are
systems that control how many trains
have crossed the rails or how many
"The application
possibilities for
torque and force
sensors in the railway
sector are very
diverse."
TORQUE AND FORCE SENSORS IN E- MOBILIT Y 01507
Our sensors
Torque sensor
Direct torque measurement: unique technology for the measurement of mechanical
forces in axes. The sensor forms a shaft-coordinated measuring system that can also
be economically produced in large quantities. Our technology creates a unique
torque sensor for serial applications.
Advantages of the torque sensor
Contactless measuring principle
Resistant to mechanical overloads
Digital literalised output signal
Robust against interference
No mechanical/magnetic treatment of the measuring point required
No specific requirements for shaft material
Resistant to deterioration
016 TORQUE AND FORCE SENSORS IN E- MOBILIT YForce sensor
Force sensors (also known as force transducers) measure the various forces acting
on an object. These include bending and axial forces (tensile and compressive
forces). Based on the principles of active magnetic torque, our sensor technology
can measure these forces accurately and without contact. The force sensor works
with any ferromagnetic test object.
Advantages of the force sensor
Contactless measurement
No treatment of the measuring point is necessary
Compact and custom design
Extremely robust under harsh conditions
Maximum long-term stability
Works with any ferromagnetic material
Resistant to overloads
TORQUE AND FORCE SENSORS IN E- MOBILIT Y 01705 Conclusion Non-contact torque and force sensors are cost-effective and are the future. With our magneto-inductive measuring principle, we have created something completely new for the measurement of torsion and forces in series applications. This is a decisive step for the development of intelligent electric mobility solutions in the future. 018 D R U CK SENSO R EN I N PR Ü FS TA N D
MagneticSenseGmbH +49 7022 40590 0 Kelterstraße 59 +49 7022 40590 29 72669Unterensingen info@magnetic-sense.de
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