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HANOI UNIVERSITY OF SCIENCE AND TECHNOLOGY SCHOOL OF TRANSPORTATION ENGINEERING -o0o - REPORT Topic: Yaw rate sensor Course name: SENSORS FOR AUTOMOTIVE APPLICATIONS Instructor: Dr Le Van Nghia Class: Automotive Engineering – Elitech K63 Members: Group I Name ID Nguyen Duy Anh 20186094 Nguyen Vu Tuan Anh 20186095 Pham Duc Anh 20186096 Nguyen Duc Bang 20186097 Hanoi, 2022 Table of contents Preface……………………………………………………………………… PART I: Overview……………………………………………………… Functions………………………………………………………………… Positions of yaw rate sensor in automobile…………………………… Classifications…………………………………………… The growth rate and market size of yaw rate sensors.…………………… Yaw rate sensor of some vehicles……………………………………… PART II: Forming and Operation……………………………………… Linear Vibrating System Based on Quartz Technology………………… 1.1 Forming……………………………………………………………… 1.2 Operation…………………………………………………………… Linear Vibrating System in Silicon Bulk- and Surface Micromachining 2.1 Forming……………………………………………………………… 2.2 Operation…………………………………………………………… Linear Vibrating System in Silicon Surface Micromachining…………… 3.1 Forming……………………………………………………………… 3.2 Operation…………………………………………………………… Rotational Vibrating System in Silicon Micromachining……………… 4.1 Forming ……………………………………………………………… 4.2 Operation…………………………………………………………… Vibrating Shell Yaw-Rate Sensor……………………………………… 5.1 Forming……………………………………………………………… 5.2 Operation …………………………………………………………… PART III: Output signal, use, and problems…………………………… Layout and output……………………………………………………… Processing……………………………………………………………… Specifications, using and fault of yaw rate sensor……………………… 3.1 Technical specifications……………………………………………… 3.1.1 Mechanical data………………………………………………… 3.1.2 Electrical data…………………………………………………… 3.1.3 CAN……………………………………………………………… 3.1.4 Characteristics…………………………………………………… 3.1.5 Connectors and Wires…………………………………………… 2 2 5 8 10 10 11 12 12 13 14 14 15 15 15 18 18 18 18 19 19 19 19 3.2 Using………………………………………………………………… 3.3 Symptoms of a faulty or damaged car yaw rate sensor……………… Checking and replacement……………………………………………… 4.1 Checking…………………………………………………………… 4.2 Replacement………………………………………………………… PART IV: Applications and attentions………………………………… Applications……………………………………………………………… Attentions………………………………………………………………… References………………………………………………………………… 20 21 23 23 23 24 24 26 28 Preface In recent years, along with the development of the economy, science and technology, and human needs Transportation has become an integral part Today, the automotive industry plays a huge role Cars help people a lot in the process of commuting, working and saving time The world automotive industry is evolving day by day, with more and more new models and types of cars appearing on the market The quality and convenience of each brand Toyota, Honda, Ford, BMW, Hyundai, Vinfast are increasingly enhanced to serve a large number of users Generations of automobiles were born one after another, marking increasingly complete development stages to achieve economic goals, dynamics, and environmental standards Many old equipment systems on cars are gradually replaced by modern structural systems to improve safety, efficiency and comfort for users Today, when the electrical systems on vehicles are more and more modern, the introduction and development of sensors have made the process of using cars easier and more convenient Besides comfort, the stability of the vehicle is also an important issue for the driver to operate the vehicle and the yaw rate sensor plays an important role in affecting this factor Realizing the importance of the yaw rate sensor, our team decided to research this sensor In the process of implementation, it is inevitable that mistakes will be made, we look forward to receiving suggestions from teachers to improve Many thanks! PART I: Overview Functions Yaw – Rate sensor is one of the extremely important sensors in the utility technologies in cars, it gives the driver comfort, safety and good control when the vehicle is operating In simpler terms, the yaw rate sensor is a key component in a vehicle’s stability control or electronic stability control system It can be defined as the movement of an object turning on its vertical axis The yaw rate sensor determines how far off-axis a car is "tilting" in a turn using gyroscopes to monitor the slip angle, the angle between the vehicle’s heading and actual movement direction By comparing the vehicle’s actual yaw rate to the target yaw rate, the on-board computer can identify to what degree the vehicle may be under- or over-steering, and what corrective action, if any, is required Corrective action may include reducing engine power as well as applying the brake on one or more wheels to realign the vehicle Positions of yaw rate sensor in automobile The yaw rate sensor is typically located under the driver or passenger seat, mounted on the level floorboard in order to access the vehicle’s center of gravity After installation, a reset/recalibration procedure is generally required Classifications We can classify Yaw-Rate sensors according to specifications as shown in the table below: Table 1: Typical specifications of the Yaw - Rate sensor Measurement principles based on mechanical gyroscopes or fiber-optic gyroscopes have been known for a long time These measurement principles provide large signal values Sensors of this kind are used, for example, in military and space travel applications However, their use in cars is impractical for reasons of cost As the accuracy requirements in cars are somewhat lower, vibration gyroscopes are used in automotive applications These sensors measure the Coriolis acceleration occurring during a rotation in connection with an oscillation movement The oscillation movement must be actively produced by the sensor These sensors therefore have two components: the drive unit and the detection unit Therefore, to classify Yaw-Rate sensors, we can classify them according to the technology of the detection unit:      Linear Vibrating System Based on Quartz Technology Linear Vibrating System in Silicon Bulk- and Surface Micromachining Linear Vibrating System in Silicon Surface Micromachining Rotational Vibrating System in Silicon Micromachining Vibrating Shell Yaw-Rate Sensor The growth rate and market size of yaw rate sensors Yaw-rate sensors are relatively new in automotive applications They were first used in 1995 in vehicle dynamics control systems More recent applications include ESP, navigation systems and rollover systems Since all these systems are still in a growth phase, these sensors have a large market potential in coming years For the year 2000, the market is estimated to be approximately $250 million, growing to more than $700 million in 2005 According to Verified Market Research, the Yaw-Rate sensor market will grow at a significant growth rate especially during the forecast period from 2018 to 2026 The market increases year by year as shown in figure Currently, there are several major yaw rate sensor manufacturers such as Bosch, ZF, Continental, Baumer, DIS sensors, Electrovac, Epson electronic Figure Global automotive yaw rate sensor market Yaw rate sensor of some vehicles  Toyota Yaw Rate Sensor 89183-50010 for Lexus LS400, RX300, Toyota Highlander, Hiace Cost: 1.570.000 VND Figure Toyota Yaw rate sensor  BMW Series E Series Mini Yaw Rate Esp Sensor 34526764018 – 6764018 Cost: 2.800.000 VND Figure BMW Yaw rate sensor PART II: Forming and Operation Linear Vibrating System Based on Quartz Technology 1.1 Forming In Figure you can see that the quartz Yaw rate sensor is essentially divided into two sections: drive and pickup A tuning fork made of quartz is stimulated in such a way that the ends oscillate in opposite directions to each other Figure Quartz Yaw rate sensor 1.2 Operation When a yaw rate occurs, the Coriolis force leads to a deflection of the ends of the tuning fork out of the oscillating plane This sensor element consists of a metal tuning fork, on which four piezo elements are located: two for the drive in the lower area and two for detection in the upper area By making the sensor element completely out of quartz, the tuning fork body itself is used both for the drive and for detection because of the piezoelectrical properties of the quartz material Suitable electrode structures supply the drive voltages and pick up the acceleration voltages Sensors such as this show very high resolution and are therefore theoretically suitable for all applications The favorable properties of the sensor element keep the evaluation electronics simple The fundamental advantages of the tuning fork structure are as follows:  Low driving voltages  The Coriolis acceleration is directly available as a voltage signal  Inherent frequency is very stable with a high Q-factor  Inherent frequencies in the range 10–40 kHz can be achieved  High level of sensitivity, resolution < 0.01/s possible  Simple electronic evaluation circuit The fundamental disadvantages are the following:  Costly mechanical manufacturing process, in some cases individual processes  Manufacturing tolerances of the sensor element often require a mechanical alignment, by laser trimming of the element for example, in order to minimize the quadrature signal  Complicated mounting technique Viewing the structure in the direction of the sensitive axis, one can recognize a principle similar to Fig 7.2.1 Owing to the paddle structure, the Coriolis forces cause torsion in the suspension, which is detected by implanted resistors These resistors change their value with mechanical stress, due to the piezoresistive effect The drive is produced by deposed and structured piezo layers This principle effectively decouples the drive and detection The divided piezo actuators allow a test signal to be applied, which causes torsion of the paddles and can be detected as yaw rate to check the functionality, even in operation Owing to the sensing axis ‘in plane’, the sensor is used in applications in which an assembly on a horizontal printed circuit board is desirable, for example in airbag control units for roll-over detection Vibrating Shell Yaw-Rate Sensor 5.1 Forming: The sensor element of this gyroscope consists of a hollow, axial symmetrical resonator, such as a ring or a cylinder It is possible to stimulate radial oscillations, which form a kind of standing wave on the wall of the cylinder 14 5.2 Operation: If the cylinder rotates around its axis, the nodes of the oscillation waves remain at rest, similar to Foucault’s pendulum In reality, the nodes move as well, but with a distance factor to the turning of the cylinder This distance factor is called the Bryan factor The moving of the nodes can be detected and is a measure for the yaw rate This principle, when produced by precision mechanics, gives an excellent resolution (about 0.01/s) and is used in the aircraft industry The following yaw-rate sensor for automotive application works on this basis (Fig 7.2.17) A hollow cylinder is stimulated to radial resonance oscillations by piezoelements located on it As the cylinder is turned around its axis, the nodes of the standing waves start to move on the cylinder wall This movement is detected by piezoelements and a closed loop system forces the nodes back, so that the waves stay constant relative to the cylinder The regulation voltage of the closed loop is a measure of the yaw rate All together eight piezoceramic elements are attached to the cylinder symmetrically and equidistant They operate as: drive, amplitude control of the drive, detectors for the oscillation nodes, and as actuators to keep the nodes in place The principle enables a complete self-test by simulating a yaw rate via the piezoactuators of the closed loop A yaw-rate sensor based on the principle of a vibrating cylinder is used in VDC systems (Fig 7.2.18) This principle has been used in a similar way in silicon micromachining and is used in a yaw-rate sensor for VDC PART III: Output signal, use, and problems Layout and output The yaw rate sensor's pin arrangement has six pins that display different information as the data passes through the sensor These details can be found in 15 the table below 16 The output signal of yaw rate sensor is in pin  DC signal  In the figure above, the output signal is in interval from 2-3V; however, the output signal of yaw rate is between 0-5V in generally  Signal voltage proportional to rate of rotation  Temperature 17 Processing Processing:  The output is ratiometric with respect to a provided reference supply A single external resistor can be used to lower the scale factor An external capacitor is used to set the bandwidth Other external capacitors are required for operation  A temperature output is provided for compensation techniques Two digital self-test inputs electromechanically excite the sensor to test proper operation of both the sensor and the signal conditioning circuits  When the output signal is processed, it is transferred to ESP and ECU to control the vehicle Specifications, using and fault of yaw rate sensor 3.1 Technical specifications 3.1.1 Mechanical data  Weight w/o wire: 65g  Size: 34x80x84 mm 18 3.1.2 Electrical data  Power supply: 7- 18 V  Maximum input current: 130 mA  CAN speed: Mbaud/s 3.1.3 CAN  CAN_ID_01 0x70 (x-axis)  CAN_ID_02 0x70 (y-axis) 3.1.4 Characteristic a) Characteristic Application     Measuring range: ±160(0/s) Over range limit±1,000°/s Absolute resolution 0.1°/s Cut-off frequency (-3 dB) 15 Hz b) Characteristic Application     Measuring range ± 4.1 g Over range limit ± 10 g Absolute resolution 0.01 g Cut-off frequency (-3 dB) 15 Hz 3.1.5 Connectors and Wires  Connector: AMP 114-18063-076  Mating connector 4-pole DRS: F 02U B00 435-01 (connector kit) F 02U 002 460-01 (connector housing) 19 Figure The yaw rate sensor of Lexus UVF46 3.2 Using Information from the vehicle body rotation sensor will be sent to other control boxes via the car's CAN network Control boxes such as the engine control box or the ABS brake control box will record the information This information can be divided into two forms: • Information on actual vehicle conditions: wheel speed, tilt angle and vehicle acceleration • Information about the driver's desired condition: steering angle, accelerator pedal position, brake pedal position By comparing the actual deflection rate with the driver's desired condition ratio to determine whether the vehicle is understeer, oversteer or understaffed The ABS control box, ESP will determine the appropriate brake fluid pressure to be applied or the engine control box will reduce engine power accordingly 20 3.3 Symptoms of a faulty or damaged car yaw rate sensor Reduced stability control – It is important to note that if you drive safely, the yaw rate sensor should never have to turn on A broken yaw rate sensor will not protect your car from tilting or sliding excessively in dangerous situations If you notice your car is more prone to tilting, you should get the yaw rate sensor checked Traction control light is on – The traction control light will illuminate when a problem is detected in your car’s traction control system A faulty yaw rate sensor can send incorrect signals to the traction control system, resulting in the light turning on consistently, or intermittently 21 Check engine light is on – The check engine light may also illuminate if the yaw rate sensor is functioning incorrectly If your car has a more advanced diagnostics system, it may state directly that there is a problem with the yaw rate sensor via the car fault codes and live data 22 Checking and replacement 4.1 Checking As mentioned above, when the yaw sensor has a problem, the vehicle's stability will decrease Therefore, to detect sensor failure, the driver can feel the stability of the vehicle, especially when cornering to check if the sensor is having problems or not In addition, we can use a dedicated device with OBD connection standards such as a G-scan device to read the fault codes of the yaw sensor:  C1280: Yaw Rate Sensor Signal Fault  C1282: Yaw Rate & Lateral G Sensor-Electrical  C1283: Yaw Rate & Lateral G Sensor-Signal 4.2 Replacement When the yaw sensor is damaged, we need to replace it to ensure the other systems work properly and the vehicle can operate stably Steps to replace a yaw rate sensor:  Step 1: Prepare materials needed 23  Step 2: Remove the old yaw rate sensor First thing you need to is disconnect your battery before dealing with electrical products  Step 3: Install the new yaw rate sensor  Step 4: Programming new yaw rate sensor  Step 5: Installing interior  Step 6: Test driving the vehicle after repairs PART IV: Applications and attentions Applications Yaw-rate sensors measure the rotation of a body along a selected axis or the change in angle per unit of time, independent of the reference system The unit of measurement is degrees per second (/s) ‘Angular rate sensor’ and ‘gyroscope’ are synonyms for ‘yaw-rate sensor’ Typical applications in the automotive sector include the following - Electronic stability program (ESP) or vehicle dynamics control (VDC)  The turning movement of a vehicle around the vertical axis is permanently monitored, for example, changes in direction due to driving through curves or skid movements The actual value is compared with that expected from the angle of the steering wheel and the vehicle’s speed If there is a difference, a computercontrolled intervention re-stabilizes the vehicle by braking one or more wheels individually In future, more sensitive systems will even be able to correct automatically for side winds (enhanced VDC), and for such purposes yaw rate sensors with a particularly 24 high resolution are required Figure Electronic stability program (ESP) - Roll-over protection  Yaw-rate sensors recognize roll-over accidents and activate safety equipment, such as head airbags, to protect the passengers - Navigation systems  Navigation systems record the position of a vehicle using satellitebased location systems (GPS) and match the determined position with the navigation system’s digital street map Yaw-rate sensors, in combination with wheel-speed sensors, permit interpolation in situations where no satellite reception is possible, such as when driving through tunnels or if the GPS signals cannot be clearly interpreted due to multiple reception as a result of reflections from houses in urban situations, for example Figure Automotive Dead-Reckoning Navigation System Based on Vehicle Speed and YAW rate 25 - Automatic distance control  A distance sensor (e.g., a radar sensor) records the distance to vehicles ahead and automatically reduces the speed if the distance to the vehicle in front is not sufficient Using a yaw-rate sensor, it is possible to pivot the recording area of the sensor when driving through curves Knowing the steering angle alone is not sufficient because of the flotation angle of the tires At present automatic distance control systems use the yaw-rate sensor of the VDC via a bus system Attentions - The application of yaw-rate sensors in vehicles requires particular attention The dynamic requirements for the sensors are high: Coriolis accelerations in the range of milli-g must be detected correctly, and at the same time the accelerations occurring in the range of several g must not interfere with the sensor function (such as when driving over potholes) In the case of the roll-over sensor this even applies for accelerations > 30 g, such as in a crash - External accelerations superimpose the sensor element’s acceleration due to the Coriolis force, that is, the desired signal By means of a symmetrical construction, it is possible to eliminate errors by subtracting the Coriolis signals of the oscillating masses; the external acceleration forces affect these masses in the same direction, the Coriolis forces, in contrast, act out-of-phase - Measurement errors occur if the linear range of the Coriolis detectors is exceeded It is therefore recommended that yaw-rate sensors, especially when permanent availability is required as in the case of vehicle dynamics control, are placed as centrally as possible inside the vehicle to reduce the influence of disturbing accelerations - Yaw-rate sensors are spring/mass systems that can be stimulated by external influences in an undesired way on one of the operating frequencies, that is on the drive frequency, the detection resonance, and (depending on the sensor system) also on the difference and summation frequencies 26 - Impacts (stones hitting against the base of the vehicle when driving on unpaved roads, potholes, accidents) cause mechanical frequencies with a broad spectrum Resonant properties of the mounting location in the car amplify these disturbances If the frequencies match with the sensor frequencies, this can lead to malfunction of the sensor, even at nominally slight external accelerations - The remedy to this is to place the resonance frequencies of the bodywork and the sensor as far apart as possible, and to make sensors with high working frequencies The mounting of mechanical dampers to prevent transfer of the bodywork resonance frequencies to the sensor is common practice Mechanical dampers within the sensor itself are also used Typical working frequencies for yaw rate sensors are 2–40 kHz, bodywork and printed circuit board resonance frequencies are typically below kHz, or for very stiff light metal bodywork, up to 20 kHz - The sensitivity of the sensors should also be taken into consideration in the car assembly The shock resistance level for typical sensors allows shock acceleration in the range of 5000 g, even for the typical fragile structures of yaw-rate sensors Undamped impacts, from assembly tooling for example, however, reach accelerations of over 10 000 g and thus can destroy the sensors or cause preliminary damage A more robust layout of the sensor is basically in conflict with the desired high sensitivity 27 References: [1] H Bolandhemmat, M Fakharzadeh, P Mousavi, “Active Stabilization of Vehicle-MountedPhased-Array Antennas,” IEEE Transactions on Vehicular Technology, 58(6):2638 – 2650 DOI: 10.1109/TVT.2008.2012159 [2] P Kim, “The Yaw Rate Sensor,” [Online] Available: http://coecsl.ece.illinois.edu/ge423/datasheets/segway/the%20yaw%20rate%20se nsor.pdf [3] A Wikstrom, “Yaw Rate and Lateral Acceleration Sensor Plausibilisation in an Active Front Steering Vehicle,” Master’s thesis, Linkopings universitet, Linkoping, 2006 [4] Huyndai, “Huyndai service training,” [Online] Available: https://en.pptonline.org/193498 [5] Mümin Tolga Emirler, Kerim Kahraman, Mutlu Şentürk, Bilin Aksun Gỹvenỗ, Levent Gỹvenỗ, Bar Efendiolu, "Vehicle Yaw Rate Estimation Using a Virtual Sensor", International Journal of Vehicular Technology, vol 2013, Article ID 582691, 13 pages, 2013 https://doi.org/10.1155/2013/582691 28