- Email: [email protected]
Microsystems for Transportation: An Overview of the Different Applications
Copyright ~ IFAC Control in Transportation Systems, Braunschweig, Germany, 2000
MICROSYSTEMS FOR TRANSPORTATION: AN OVERVIEW OF THE DIFFERENT APPLICATIONS
Dr. Eric MouDier
Yole Developpement 45 rue Sainte Genevieve 69006 Lyon FRANCE Tel: + 33472 83 01 81 Fax: + 33472 83 01 83 Email: [email protected]
Abslract: The total world market for microsystems is expected to grow from $ 14 billion to $ 38 billion by the year 2002 according to the Nexus market survey. One of the reasons for this increase is a broad diffusion of microsystems in all the aspects of our every-day life. From the IT/peripherals industry to medical and automotive industry (which are at the moment the largest identified markets). The sensing function of microsystems is particularly well adapted to transportation for navigation and guiding systems, security applications or engine control in automotive and aeronautics applications. Copyright ~ 2000 IFAC Keywords: Microsystems, transportation
1. IN1RODUcnON Navigalion Air Data. IflSlflllMnlS. Flight COnlrol, GPS "c.i",r ,{ anu/IIUU
In this article, rnicrosystems for transportation are defined as microsystems which are used in transport systems (cars, airplanes ... ) for security, engine / vehicle control and guidance. Fig. I and 2 show the main applications in automotive and aeronautics.
IMrtioJ M~asurtme1W Uniu
Antiskid. active slISfHnsion..
Air conditioning GtMrarion monitorin,
Prusurt Humidity..
air pressure injection. gas exhaust COn/To', oiJqualiJ)', automatic gear bo~ cOnlrol...
FADEC Hydraulics
~
Clulssis stabilisation
Engine and gear box
Engine and retl£tors
I
L4nding systems Hydraulic p"snu< , Tyre prusurt. ttc..
Stnuhln monitoring Vibrations
StabilisaJion SInIaU" farig~
Fig. 2: Aeronautics applications of Microsystems (Nexus, 1999)
lnstrununtation air condiJioning 0nJi·/"'ft sysum. gwdanc. sySl
Thus, main rnicrosystems used in transportation are pressure sensors, accelerometers (one and dual axis), inclinometers (which are also accelerometers) and inertial sensors.
Fig. I: Automotive applications of microsystems (Nexus, 1999)
51
The following table shows the world sensors market in evolution for the microsystems used transportation.
I
Table I Evolution of the world sensors market for transportation (Nexus source) 1996 Pressure sensors for automotive applications Pressure sensors for aerospace applications I-axis accelerometer for automotive applications (airbag active suspension) I-axis accelerometer for aerospace applications Inenial sensor for automotive applications (angular rate. gyroscope) Inertial sensor for aerospace applications Inclinometers
16 M units. 65 M $
2002 95 M units. 490 M $
1 M units. 50 M $
1.3 M units. 52 M $
12 M units. 78 M $
66 M units. 190 M $
2 M units. 30 M $
3 M units. 40 M $
530 k units. 10.6 M
17 M units. 60 M $
• • •
Accelerometer Yaw rate sensor RoIl-over sensor Child seat presence
•
Occupant Classification System
• •
Radar sensor Image sensor
SAFETY
Tire parameter sensors
Intelligent tail lights
Airbag
H
On board ,
lntilrl:atnr
$
200 k units. 40 M $
400 k units. 60 M $
I M units. 10 M $
20 M units. 70 M $
Fig. 3: Safety parameters in automotive applications and used microsystems
I
In 1996, pressure sensors for automotive were mainly for air pressure injection application (MAPIBAP). In 2002, new applications will cover gear box, tire monitoring, fuel tank monitoring, engine oil monitoring, turbo monitoring, exhaust fume pressure.
•
2. MAIN FUNCTIONS OF MICROSYSTEMS USED IN TRANSPORTATION IN AUTOMOTIVE: SAFETY, TRAFFIC MANAGEMENT, ENGINE OPTIMIZATION AND COMFORT
TRAFFIC MANAGEMENT
•
Electromagnetic waves communication Gyroscope
•
Accelerometer
Display
Fig. 4: Traffic management parameters
I
The safety-related microsystems market is widely encouraged thanks to both the integration of airbags in all categories of cars and the people being more sensitive about the safety aspect in their cars. New developments of accelerometers, yaw rate and rollover sensors, child seat presence and occupant classification systems make it necessary to improve the airbag's ability to detect external events. The next safety system generation will certainly include radar systems and telemetry (Fig. 3).
• • •
Pressure sensor How sensor Temperature sensor
•
I
Traffic management systems are, for the moment, only available in the most expensive cars due to their price. They are expensive because of the complex gyroscope technology and GPS communication system (Fig.4).
ENGINE OPTfMlZAnON
Rotary position sensor
Oil quality sensor
~
Engine parameters
On board indicator ~----
Fig. 5: Engine optimization parameters and used microsystems
Smart engine management will be the next step for the intelligent car concept thanks to the versatile development of new sensors dedicated to engine parameters like pressure, flow, temperature, rotary position or oil quality sensor (Fig. 5).
A new market for microtechnology is emerging to optimize in-car comfort. It includes air quality
52
sensors for air damper and hands-free microphone systems for mobile phones (Fig. 6).
I • •
•
Some companies already deliver gyroscopes. They are Murata for navigation systems, British Aerospace for ACC, Motorola for GPS (the Motorola's microsystem will integrate both a gyroscope and an accelerometer on the same chip) and Analog Devices.
COMFORT
Air qualily sensor Air damper Hands- free microphone
.
3.2. Pressures sensors On board parameters
Main applications of pressure sensors for transportation in automotive are automatic gearboxes, hydraulic suspensions, braking systems
Pressures to be measured are high (more than 100 atm) and the automatic gearboxes market is expected to reach 25% in 2005 from 10% today in Europe.
Fig. 6: In-car comfort parameters and used microsystems
3. EXAMPLE OF TRANSPORTATION
MICROSYSTEMS
Today existing markets for pressure sensors automotive are the followings: In 1996: MAP: 15 M units, 45 M $ Fuel injection: 1 M units, 20 M $ In 2002: MAP: 30 M units, 30 M $ Fuel injection: 8 M units, 80 M $
IN
3.1. Gyroscopes
Gyroscopes are microsystems which measure an acceleration and velocity in more than one direction. Whereas ring-laser gyroscopes and fiber-optics gyroscopes range from $ 2 000 to $ 30 000, micromachined gyroscopes (quarts piezoresistive or silicon) are good candidates to enter the automotive market. The price objective for micro-machined gyroscopes to enter this market is below $ 20; in this condition, the automotive industry will become a major end-user of these sensors for applications like: • Navigation (development of the GPS has significantly affected the market for gyroscopes) • Safety: roll over and yaw rate sensing systems
In
New emerging applications for pressure sensors in 2002 will be the followings (Nexus source): Gear box: 4 M units, 20 M $ Tire monitoring: 30 M units, 90 M $ Engine oil pressure: 7 M units, 50 M $ Fuel tank monitoring: 10 M units, lOOM $ Exhaust fume pressure:5 M units, 45 M $ Turbo monitoring: 1 M units, 15 M $ 3.3. Accelerometers and inclinometers
Microsystems can also be used for shocks recording in transportation of fragile components. Usually the combination of 3 accelerometers are used (for tridirectional detection). The French company Acorvitas manufactures and sells events recording modules which can detect and record shocks but also vibration, temperature, relative humidity, pressure, electric voltage, speed ... (Fig. 7).
Producing low-cost silicon-micromachined gyroscopes for the automotive industry is thus a major objective of the European industry. In 1996, the world inertial micromachined sensor market was of 150 M$ (6 M of units) and the market share of Europe was 15 %. In automotive, angle rate sensors should allow to position the vehicle in case of lose of satellite signal for GPS applications; the operating range is +1- 80 o /s. For ACC (Adaptive Cruise Control) and stability control systems in automotive, the operating range should be higher, i.e. in the +1- 1000 ls range. In the short-term (2 to 3 years), dynamic control systems (stability control systems and ACq will be the main applications for angle rate sensor after navigation systems; low-end cars could be equipped. For roll-over applications, accelerometers might also be used but to make the difference between steering operation and roll-over, angle rate sensors seem to be preferred.
Fig. 7: Acorvitas' black box Accelerometers might also be used for others applications in transportation. The most common is 53
for air-bag but emerging applications cover dynamic control systems in car (such as the Vehicle Dynamic Control system developed by Bosch with a dual function Si-micromachining sensor: lateral acceleration sensor and yaw rate sensor).
4. CONCLUSIONS This paper presented a few examples of microsystems used in transport systems: pressure sensors, accelerometers and inclinometers, gyroscopes, anti-colliding systems. In the automotive field, microsystems has a significant impact and traffic control will be of increasing concern with distance and speed measurement or alarm systems for rain, fog or ice. Aeronautics also had a dramatic impact on microsystems as pressure sensors used today in car were first developed for aircraft. Furthermore, microsystems are diffusing technologies; therefore, they can be used in applications such as parcels tracking.
3.4. Microsystems for anti-colliding systems Anti-colliding systems are a promising applications for microsystems. The technology may be a radar (Volvo, Mercedes) or the use of a micro-laser with a scanner for telemetry. Necessity of integration leads to smaller and smaller systems. Leti in Grenoble (France) has developed a micro-optical scanner for detecting obstacles on the road.
The small size, the reliability, the improved performances, the low-cost and the new functionality of microsystems are well suitable for applications in transportations. It is forecasted that, in the future, further integration of systems will lead to more and more microsystems in vehicles (at the moment, a car contains about 80 sensors).
The instrument (Fig. 8), developed by Leti is a one Two dimensional scanner etched in silica. cylindrical microlenses, one placed in front of the other along the optical axis, are driven by a set of electrostatic combs that deflect a laser beam. The electrostatic actuator scans the beam in one direction by translating the movable microlenses at right angles to the beam propagation. As the lenses are displaced laterally relative to each other, the wave plane emerges collimated but tilted from the optical axis.
REFERENCES Nexus Task Foo:e (1999). Market analysis for microsysterns 1996-2002
Fig. 8: Electrostatic combs move the microlenses situated in the center of the device (Sensors and Actuators 73 1999) The source is a YAG microlaser at 1.06 Jlrn. pumped by a laser diode. Emission is in the visible or infrared, depending on the application. A KTP crystal frequency doubles the emission to 533 nm. More than 700 chips fit onto a 100 mm diameter silicon wafer during manufacture, making the devices cheap. Leti is now developing a two-dimensional version, where the beam is perpendicular to the plane of the device, not along it. Another project using laser telemetry is the Esprit OLMO project. CSEM has developed an innovative pre-industrial scanning range sensor based on laser radar techniques.
54
MICROSYSTEMS FOR TRANSPORTATION: AN OVERVIEW OF THE DIFFERENT APPLICATIONS
Dr. Eric MouDier
Yole Developpement 45 rue Sainte Genevieve 69006 Lyon FRANCE Tel: + 33472 83 01 81 Fax: + 33472 83 01 83 Email: [email protected]
Abslract: The total world market for microsystems is expected to grow from $ 14 billion to $ 38 billion by the year 2002 according to the Nexus market survey. One of the reasons for this increase is a broad diffusion of microsystems in all the aspects of our every-day life. From the IT/peripherals industry to medical and automotive industry (which are at the moment the largest identified markets). The sensing function of microsystems is particularly well adapted to transportation for navigation and guiding systems, security applications or engine control in automotive and aeronautics applications. Copyright ~ 2000 IFAC Keywords: Microsystems, transportation
1. IN1RODUcnON Navigalion Air Data. IflSlflllMnlS. Flight COnlrol, GPS "c.i",r ,{ anu/IIUU
In this article, rnicrosystems for transportation are defined as microsystems which are used in transport systems (cars, airplanes ... ) for security, engine / vehicle control and guidance. Fig. I and 2 show the main applications in automotive and aeronautics.
IMrtioJ M~asurtme1W Uniu
Antiskid. active slISfHnsion..
Air conditioning GtMrarion monitorin,
Prusurt Humidity..
air pressure injection. gas exhaust COn/To', oiJqualiJ)', automatic gear bo~ cOnlrol...
FADEC Hydraulics
~
Clulssis stabilisation
Engine and gear box
Engine and retl£tors
I
L4nding systems Hydraulic p"snu< , Tyre prusurt. ttc..
Stnuhln monitoring Vibrations
StabilisaJion SInIaU" farig~
Fig. 2: Aeronautics applications of Microsystems (Nexus, 1999)
lnstrununtation air condiJioning 0nJi·/"'ft sysum. gwdanc. sySl
Thus, main rnicrosystems used in transportation are pressure sensors, accelerometers (one and dual axis), inclinometers (which are also accelerometers) and inertial sensors.
Fig. I: Automotive applications of microsystems (Nexus, 1999)
51
The following table shows the world sensors market in evolution for the microsystems used transportation.
I
Table I Evolution of the world sensors market for transportation (Nexus source) 1996 Pressure sensors for automotive applications Pressure sensors for aerospace applications I-axis accelerometer for automotive applications (airbag active suspension) I-axis accelerometer for aerospace applications Inenial sensor for automotive applications (angular rate. gyroscope) Inertial sensor for aerospace applications Inclinometers
16 M units. 65 M $
2002 95 M units. 490 M $
1 M units. 50 M $
1.3 M units. 52 M $
12 M units. 78 M $
66 M units. 190 M $
2 M units. 30 M $
3 M units. 40 M $
530 k units. 10.6 M
17 M units. 60 M $
• • •
Accelerometer Yaw rate sensor RoIl-over sensor Child seat presence
•
Occupant Classification System
• •
Radar sensor Image sensor
SAFETY
Tire parameter sensors
Intelligent tail lights
Airbag
H
On board ,
lntilrl:atnr
$
200 k units. 40 M $
400 k units. 60 M $
I M units. 10 M $
20 M units. 70 M $
Fig. 3: Safety parameters in automotive applications and used microsystems
I
In 1996, pressure sensors for automotive were mainly for air pressure injection application (MAPIBAP). In 2002, new applications will cover gear box, tire monitoring, fuel tank monitoring, engine oil monitoring, turbo monitoring, exhaust fume pressure.
•
2. MAIN FUNCTIONS OF MICROSYSTEMS USED IN TRANSPORTATION IN AUTOMOTIVE: SAFETY, TRAFFIC MANAGEMENT, ENGINE OPTIMIZATION AND COMFORT
TRAFFIC MANAGEMENT
•
Electromagnetic waves communication Gyroscope
•
Accelerometer
Display
Fig. 4: Traffic management parameters
I
The safety-related microsystems market is widely encouraged thanks to both the integration of airbags in all categories of cars and the people being more sensitive about the safety aspect in their cars. New developments of accelerometers, yaw rate and rollover sensors, child seat presence and occupant classification systems make it necessary to improve the airbag's ability to detect external events. The next safety system generation will certainly include radar systems and telemetry (Fig. 3).
• • •
Pressure sensor How sensor Temperature sensor
•
I
Traffic management systems are, for the moment, only available in the most expensive cars due to their price. They are expensive because of the complex gyroscope technology and GPS communication system (Fig.4).
ENGINE OPTfMlZAnON
Rotary position sensor
Oil quality sensor
~
Engine parameters
On board indicator ~----
Fig. 5: Engine optimization parameters and used microsystems
Smart engine management will be the next step for the intelligent car concept thanks to the versatile development of new sensors dedicated to engine parameters like pressure, flow, temperature, rotary position or oil quality sensor (Fig. 5).
A new market for microtechnology is emerging to optimize in-car comfort. It includes air quality
52
sensors for air damper and hands-free microphone systems for mobile phones (Fig. 6).
I • •
•
Some companies already deliver gyroscopes. They are Murata for navigation systems, British Aerospace for ACC, Motorola for GPS (the Motorola's microsystem will integrate both a gyroscope and an accelerometer on the same chip) and Analog Devices.
COMFORT
Air qualily sensor Air damper Hands- free microphone
.
3.2. Pressures sensors On board parameters
Main applications of pressure sensors for transportation in automotive are automatic gearboxes, hydraulic suspensions, braking systems
Pressures to be measured are high (more than 100 atm) and the automatic gearboxes market is expected to reach 25% in 2005 from 10% today in Europe.
Fig. 6: In-car comfort parameters and used microsystems
3. EXAMPLE OF TRANSPORTATION
MICROSYSTEMS
Today existing markets for pressure sensors automotive are the followings: In 1996: MAP: 15 M units, 45 M $ Fuel injection: 1 M units, 20 M $ In 2002: MAP: 30 M units, 30 M $ Fuel injection: 8 M units, 80 M $
IN
3.1. Gyroscopes
Gyroscopes are microsystems which measure an acceleration and velocity in more than one direction. Whereas ring-laser gyroscopes and fiber-optics gyroscopes range from $ 2 000 to $ 30 000, micromachined gyroscopes (quarts piezoresistive or silicon) are good candidates to enter the automotive market. The price objective for micro-machined gyroscopes to enter this market is below $ 20; in this condition, the automotive industry will become a major end-user of these sensors for applications like: • Navigation (development of the GPS has significantly affected the market for gyroscopes) • Safety: roll over and yaw rate sensing systems
In
New emerging applications for pressure sensors in 2002 will be the followings (Nexus source): Gear box: 4 M units, 20 M $ Tire monitoring: 30 M units, 90 M $ Engine oil pressure: 7 M units, 50 M $ Fuel tank monitoring: 10 M units, lOOM $ Exhaust fume pressure:5 M units, 45 M $ Turbo monitoring: 1 M units, 15 M $ 3.3. Accelerometers and inclinometers
Microsystems can also be used for shocks recording in transportation of fragile components. Usually the combination of 3 accelerometers are used (for tridirectional detection). The French company Acorvitas manufactures and sells events recording modules which can detect and record shocks but also vibration, temperature, relative humidity, pressure, electric voltage, speed ... (Fig. 7).
Producing low-cost silicon-micromachined gyroscopes for the automotive industry is thus a major objective of the European industry. In 1996, the world inertial micromachined sensor market was of 150 M$ (6 M of units) and the market share of Europe was 15 %. In automotive, angle rate sensors should allow to position the vehicle in case of lose of satellite signal for GPS applications; the operating range is +1- 80 o /s. For ACC (Adaptive Cruise Control) and stability control systems in automotive, the operating range should be higher, i.e. in the +1- 1000 ls range. In the short-term (2 to 3 years), dynamic control systems (stability control systems and ACq will be the main applications for angle rate sensor after navigation systems; low-end cars could be equipped. For roll-over applications, accelerometers might also be used but to make the difference between steering operation and roll-over, angle rate sensors seem to be preferred.
Fig. 7: Acorvitas' black box Accelerometers might also be used for others applications in transportation. The most common is 53
for air-bag but emerging applications cover dynamic control systems in car (such as the Vehicle Dynamic Control system developed by Bosch with a dual function Si-micromachining sensor: lateral acceleration sensor and yaw rate sensor).
4. CONCLUSIONS This paper presented a few examples of microsystems used in transport systems: pressure sensors, accelerometers and inclinometers, gyroscopes, anti-colliding systems. In the automotive field, microsystems has a significant impact and traffic control will be of increasing concern with distance and speed measurement or alarm systems for rain, fog or ice. Aeronautics also had a dramatic impact on microsystems as pressure sensors used today in car were first developed for aircraft. Furthermore, microsystems are diffusing technologies; therefore, they can be used in applications such as parcels tracking.
3.4. Microsystems for anti-colliding systems Anti-colliding systems are a promising applications for microsystems. The technology may be a radar (Volvo, Mercedes) or the use of a micro-laser with a scanner for telemetry. Necessity of integration leads to smaller and smaller systems. Leti in Grenoble (France) has developed a micro-optical scanner for detecting obstacles on the road.
The small size, the reliability, the improved performances, the low-cost and the new functionality of microsystems are well suitable for applications in transportations. It is forecasted that, in the future, further integration of systems will lead to more and more microsystems in vehicles (at the moment, a car contains about 80 sensors).
The instrument (Fig. 8), developed by Leti is a one Two dimensional scanner etched in silica. cylindrical microlenses, one placed in front of the other along the optical axis, are driven by a set of electrostatic combs that deflect a laser beam. The electrostatic actuator scans the beam in one direction by translating the movable microlenses at right angles to the beam propagation. As the lenses are displaced laterally relative to each other, the wave plane emerges collimated but tilted from the optical axis.
REFERENCES Nexus Task Foo:e (1999). Market analysis for microsysterns 1996-2002
Fig. 8: Electrostatic combs move the microlenses situated in the center of the device (Sensors and Actuators 73 1999) The source is a YAG microlaser at 1.06 Jlrn. pumped by a laser diode. Emission is in the visible or infrared, depending on the application. A KTP crystal frequency doubles the emission to 533 nm. More than 700 chips fit onto a 100 mm diameter silicon wafer during manufacture, making the devices cheap. Leti is now developing a two-dimensional version, where the beam is perpendicular to the plane of the device, not along it. Another project using laser telemetry is the Esprit OLMO project. CSEM has developed an innovative pre-industrial scanning range sensor based on laser radar techniques.
54