Automobile Chassis Electronic Control Technology Paper 1: Automobile Chassis Structure and Maintenance Technology
Abstract: Chassis, as an important part of vehicles, is a powerful guarantee for normal and safe driving of vehicles. It includes four parts: transmission system, driving system, steering system and braking system, and each sound B has its special function. With the increasing popularity of automobiles and frequent accidents caused by untimely and inadequate vehicle maintenance, it is necessary for car owners to understand the structure of automobile chassis and master the necessary maintenance techniques to ensure safe and stable driving.
introduce
With the development of social economy and the improvement of people's living standards, the popularity of automobiles is getting higher and higher, which plays an increasingly prominent role in social production and life. However, in the process of using their own cars, many car owners lack the corresponding knowledge and skills of car construction and maintenance, which leads many car owners to have various faults easily due to improper use on the one hand, and unable to carry out necessary and capable maintenance on the other hand. In addition, although some car owners have certain maintenance skills and experience, they mainly focus on the engine and the car itself, but they know little about the maintenance of the chassis, even the basic structure is not clear. With the emergence of road accidents caused by more and more frequent vehicle chassis failures, it is necessary to introduce and summarize the structure of vehicle chassis and related maintenance technologies in order to provide some useful reference for the majority of car owners.
1 Structure of automobile chassis
The structure of automobile chassis can be divided into four parts: transmission system, driving system, steering system and braking system. They are described in detail one by one below.
1. 1 drive train
Automobile transmission refers to all power transmission devices from the engine to the driving wheels. Its types include mechanical transmission, hydraulic tradition and so on, which can meet the needs of different types of cars with different functional positioning. The structure of the transmission system includes a clutch for cutting off or transmitting the power input from the engine to the transmission, a transmission for changing the running speed and traction, and a main reducer for changing the transmission direction. Its basic function is to transfer the torque of the engine to the driving wheels, and at the same time, it is necessary to adapt to the needs of the situation and change the torque. Taking the common mechanical transmission system as an example, the power generated by the engine passes through the universal transmission device composed of clutch, transmission, universal joint and transmission shaft, the main reducer, differential and the half shaft installed in the drive axle in turn, and finally is transmitted to the driving wheel. Transmission system has many functions in automobile running, including the most commonly used deceleration, speed change, reversing, power interruption and so on. At the same time, it can also effectively cooperate with the engine to perform various tasks, effectively ensuring the driving safety of the car.
1.2 drive system
The driving system mainly consists of four parts: frame, axle, wheel and suspension. Its main function is to receive power from the transmission system, and then form traction force on the vehicle through the interaction between the driving wheel and the road surface, so that the vehicle has the power to run normally. In addition, the driving system also bears the reaction force of the total weight of the car and the ground [2]; When driving on the highway, it can also effectively alleviate the impact of the road on the car body, reduce the vibration of the car, keep the car running smoothly and ensure the handling stability of the car.
1.3 steering system
Automobile steering system refers to a special mechanism used to adjust the driving direction on the automobile. It is mainly composed of steering control mechanism, steering gear and steering transmission mechanism. Automobile steering is generally realized by the driver by manipulating the parts of the steering system to change the steering angle. Its function is to ensure that the car can drive in the direction chosen by the driver and keep the car running steadily in a straight line. Automobile steering system includes two categories: one is the steering system that depends entirely on the driver's operation, that is, the mechanical steering system; The other is the power steering system. At present, more and more cars begin to use power steering system. Power steering system can be further subdivided into hydraulic power steering system, electric power steering system and pneumatic power steering system.
1.4 Brake system
The braking system is a special device used to make the road surface exert a certain pressure on the automobile wheels, so as to achieve a certain degree of braking. Its main functions include: when driving at different speeds, forcing the car to slow down and stop according to the driver's needs, making the stopped car park stably under various road conditions, including ramps, and keeping the car running at a stable speed on downhill sections. Only the external force acting on the car in the opposite direction to the direction of the car can make the car brake. Because the magnitude and timing of these external forces are random and the driver can't control them, in order to realize the above functions, the car must be equipped with some special devices. Nowadays, many car owners are aware of the important role of braking system in driving safety. Therefore, the braking system of their vehicles is generally equipped with anti-lock braking system (ABS), which can effectively control the slip rate and keep the wheels rotating at the maximum braking torque, thus providing a strong guarantee for the maneuverability and stability of the vehicle when braking.
2 car chassis maintenance
2. 1 Inspection and adjustment of clutch pedal
First, measure the free stroke of the clutch pedal. Gently step on the clutch pedal with your hand, and measure the descending distance of the pedal with a ruler when there is resistance. Secondly, adjust the free stroke of the clutch pedal. Loosen the lock nut and turn the push rod, and tighten the lock nut after adjustment. Measure the clutch pedal stroke again. Press the clutch pedal to the bottom and measure the distance between the starting position and the ending position with a ruler. Finally, adjust the stroke of the clutch pedal. Loosen the lock nut and turn the bolt. Tighten the lock nut after adjusting the clutch pedal stroke.
2.2 Replacement of the ball joint of the tie rod (it is recommended to replace both sides at the same time)
First, remove the outer ball joint of the tie rod. Remove the wheel, mark the tie rod, then remove the outer ball nut, and disconnect the outer ball joint from the steering knuckle with the ball joint removal tool KM-507-B. Loosen the tie rod adjusting nut and remove the outer ball joint from the tie rod by twisting. Secondly, the installation of the steering tie rod. Align the mark on the tie rod and reposition the adjusting nut. Twist to install the outer ball joint on the tie rod, and then connect the outer ball joint to the steering knuckle. Then adjust the toe-in of the front wheel and tighten the adjusting nut of the outer ball joint of the tie rod. Third, remove the ball head in the tie rod. Disassemble the wheel, tie rod outer ball joint, dust sleeve fixing clip, dust sleeve and tie rod inner ball joint in turn. Finally, install the ball joint on the tie rod. The first step is to install and tighten the ball joint in the tie rod. Then install the steering gear dust cover, dust cover fixing clip, steering tie rod outer ball joint and wheel in turn.
2.3 Inspection and adjustment of neutral start switch
2.3. 1 neutral start switch inspection
The first step is to use the parking brake and turn on the ignition switch. Step 2: Press the brake pedal and check that the engine can be started when the shift lever is in N or P position, but it cannot be started in other positions. Finally, check and make sure that when the shift lever is in the R position, the backup lamp lights up and the backup warning buzzer sounds, but it doesn't work in other positions. If a fault is found, check the continuity of the neutral start switch.
2.3.2 Adjustment of neutral start switch The first step is to loosen the bolt of neutral start switch and put the gear lever in the N position. Then align the groove with the neutral reference line, fix the switch in place, and then tighten the two bolts. The torque is 5.4 N-m. After adjustment, check the operation of the switch.
2.4 Replacement of Front Shock Absorber
The replacement of the front shock absorber is divided into four parts.
2.4. 1 Disassembly of front pillar assembly
Remove the pillar upper cover and nut, lift and properly support the vehicle, and then remove the tire. On vehicles equipped with anti-lock braking system (ABS), disconnect the ABS sensor line from the pillar assembly; After removing the brake oil pipe from the strut assembly bracket, remove the nut from the stabilizer link to the strut assembly and disconnect the stabilizer link. Remove the nuts and bolts of the steering knuckle to strut assembly and disconnect the steering knuckle. Finally, you can remove the pillars. Always like this.
2.4.2 Removal of front shock absorber
After removing the strut assembly, fix the strut assembly to the spring compression tool to ensure that the hook is properly supported on the strut spring. Then use the spring compression tool to compress the front spring, hold the threaded piston rod with an open-ended wrench, and remove the piston nut and washer with a double-ring wrench, which is faster. Next, remove the upper column seat, seat bearing, upper spring seat, upper ring damping pad and hollow bumper. After removing these, loosen the spring and remove the spring and the lower ring damping pad.
2.4.3 Assembly of front shock absorber
Install the lower ring damping pad and spring. Use the spring compression tool KM-329-A to compress the spring. Then install the hollow bumper, upper ring damping pad, front spring seat, upper spring seat, upper column seat and seat bearing to ensure that the upper spring seat is stuck on the front spring seat. After completing the above steps, start to install and tighten the piston rod nut, and finally loosen the spring compression tool.
2.4.4 Install the front column assembly.
The first step is to install the strut assembly, and then install the nuts and bolts from the steering knuckle to the strut assembly to connect the strut assembly to the steering knuckle. Tighten the nuts and bolts of the steering knuckle to strut assembly. Then connect the stabilizer bar to the strut assembly nut, connect the stabilizer bar to the strut assembly, and fasten the stabilizer bar to the strut nut. When this is done, install the brake oil pipe on the strut assembly bracket. If ABS is installed on a vehicle, connect the line of ABS sensor to the pillar assembly. Then install the wheels and lower the vehicle. Finally, install the fixing nut of the column assembly on the vehicle body and fasten the column assembly to the vehicle body nut.
3 Conclusion
With the more and more extensive application of cars in people's lives, it plays an increasingly important role. In order to play its role better, it is necessary to master certain automobile maintenance technology. Especially the chassis, which is called the second heart of the car, needs to strengthen the understanding of its structure and master certain maintenance skills.
References:
[1] Xiaole. The chassis supports a moving sky [J]. Automobile and safety, 2012 (07):1315.
[2] Lin. Discussion on the Maintenance and Repair of Automobile Chassis [J]. Guide to Getting Rich by Science and Technology, 20 13 (18): 33 37.
Ma Guochen. Research on Integrated Control of Automobile Chassis System Based on Hierarchical Structure [D]. Zhejiang University 20 1 1: 3339.
Electronic control technology of automobile chassis Part II: New technology of automobile chassis control
With the development of automobile technology, there are various controllers designed for different functions of automobile, and the development of new control of automobile chassis is advancing by leaps and bounds, which greatly improves the overall performance of automobile and ensures the stability and durability of automobile. Through the analysis of new control technologies of automobile chassis, it is pointed out that these new control technologies play an important role in the safety, power and handling stability of automobile, and it is hoped that the application of these new control technologies of automobile chassis can further promote the strengthening and improvement of automobile performance.
Keywords: automobile chassis; Control technology; Wire control technology; electronic technique
With the rapid development of automobile industry, more and more new technologies are applied to automobiles, and the control technology of automobile chassis is constantly being renovated to continuously improve the performance of automobiles. At present, the new technologies of automobile chassis mainly include brake-by-wire system and active suspension control system. These latest research and development trends are to use high-speed network to connect various control systems into a whole to form an integrated control system, which greatly improves the safety initiative, maneuverability and comfort of automobiles.
1 Automotive Chassis Electronic Technology
1. 1 Electronic Stability Control System (ESP)
Electronic Stability Program (ESP) is mainly composed of steering sensor, wheel sensor, sideslip sensor, lateral acceleration sensor, steering wheel and brake pedal sensor.
ESP system belongs to the automobile active safety control system, which uses various sensors to monitor the shape and state of the automobile and the driver's manipulation, so that the computer can accurately calculate the instability degree of the automobile and get the adjustment parameters for restoring stable driving. When the car is unstable due to abnormal changes in road adhesion or improper driver control, it can be adjusted by ESP system, which can effectively restrain the side slip of front and rear wheels and solve the instability problem caused by understeer and oversteer. ESP system is actually the highest form of intelligent active anti-skid stability system, which can make the car always run and run under the condition of consistent inertial force and driving direction, restrain the car from slipping out of control in time, reduce the probability of side collision and avoid accidents.
1.2 full-circuit braking system (BBW)
BBW system is a brand-new braking mode, and its system structure includes electric brake, control unit, electronic brake pedal, connecting wire and so on. Full-loop braking system is a new type of intelligent braking system. By adopting embedded bus technology, it can work in cooperation with anti-lock braking system, traction control system and other automobile active safety systems. By optimizing the control algorithm in the microprocessor, the working process of the braking system can be accurately adjusted, thus improving the braking effect of the vehicle and enhancing the braking safety performance of the vehicle. BBW system is a new thing, which has many incomparable advantages compared with traditional braking system, and can greatly improve the performance of automobile safety. Although the application of BBW system is still limited at present, with the increasing interest of the automobile industry in BBW system, BBW system will be rapidly popularized in automobiles and eventually replace the traditional hydraulic braking system in small and medium-sized vehicles.
1.3 automobile suspension control system
Car wash suspension control system mainly includes active suspension damper control system (ADC) and active lateral stabilizer (ARC). ADC consists of electronic control unit, CAN and four vertical acceleration sensors. It can adjust the damping proportional valve accordingly, automatically adjust the height of the vehicle and restrain the change of the vehicle. So that the suspension system of the vehicle can better ensure the comfort, safety and stability of the vehicle. ARC mainly makes the left and right ends of the active stabilizer bar move relatively in the vertical direction, so that the roll angle of the car body is close to zero, thus improving the comfort of the car. Because the front and rear active stabilizers can adjust the distribution ratio of automobile sound roll torque, it can effectively adjust the dynamic characteristics of the automobile and improve the safety and maneuverability of the automobile.
2 car chassis wire control technology
The so-called by-wire control refers to replacing the components connected by mechanical, hydraulic or pneumatic systems in the past with the transmission of electronic signals, such as shift linkage and steering gear transmission mechanism. It not only replaces the connection, but also changes the control mechanism and control mode. The application of this technology will change the traditional structure of cars. The by-wire control technology has simple structure, which not only reduces the manufacturing cost, but also reduces the space required by the chassis, increases the seating space and is sensitive to control. Because the drive-by-wire technology is driven by a motor, the motor turns into a generator, so in the braking process, part of the energy will be converted into electric energy and stored, and the control signal can be directly provided by the satellite through GPS processing. This not only provides security for car theft, but also provides technical support for unmanned driving. At present, the application of by-wire technology is not very extensive, but its development space is very broad. With the improvement of the reliability of electronic equipment and the development of corresponding technology, the application of wire control technology will be more extensive in the future.
3 automobile chassis integration technology
Integration 3. 1 ABS/ASR/ESP
The integration of ABS/ASR device has successfully solved the problem of directional stability when braking and driving, but the directional stability when turning is still not guaranteed. ESP sensors can be used to monitor the shape and state of the car and the driver's control actions, so as to brake the wheels, correct the driving direction for the car and ensure that the car can remain stable when turning. Therefore, the application of ABS/ASR/ESP integrated system greatly meets the driver's stability requirements in braking, acceleration and steering, and makes great contributions to the active driving safety of automobiles.
3.2 integration of ABS/ASP/ACC
Based on the hardware of ABS/ASR electronic control device, the electronic circuit for receiving the signal from the distance sensor and the electronic drive circuit of ACC normally closed and normally driven oil solenoid valve can be effectively added. Based on the existing ABS control module and ASR control module, ACC control module is added, which can be integrated with ABS/ASR electronic control module to process, calculate and determine the formal state of the car and the rotating state of the wheel in real time. The integration of the three has the function of giving priority to the driver's operation and giving priority to the work.
4 automobile chassis networking technology
In the current automobile development process, almost every automobile is a comprehensive device of machinery, electronics and information, and the distribution of electronics and information department in the system plays an increasingly important role. With the increasing number of automotive electronic equipment, reducing wiring harness is a key issue, and the weight and space occupied by lines will reduce efficiency, so the network structure based on serial communication transmission will inevitably become a trend choice. At present, CAN bus is a mature application of automobile chassis networking, and the application of WLAN in automobile chassis is also being further explored. As a new technical standard of short-distance wireless communication, Bluetooth technology has great market potential in the application of automobile chassis control system, and it has been unanimously recognized by the automobile industry because of its relatively low cost and simple use mode, and its application in the future development of the automobile industry is limitless.
5 concluding remarks
With the application of new chassis control technology in automobiles, the development of automobile industry is becoming more and more prosperous, the performance of automobiles is constantly improved, and the safety and stability are greatly improved. The application of new technology of automobile chassis has greatly promoted the development of automobile industry and brought great economic and social benefits.
refer to
[1] Chen. Present situation and development trend of automobile chassis control technology [J]. Automotive Engineering, 2007,02.
Zong Changfu, Liu Kai. Development of automotive by-wire technology [J]. Automotive Technology, 2007,03.
Qiu, man. New Technology of Automobile Safety Chassis [J]. Silicon Valley, 20 10, 17.
Automobile Chassis Electronic Control Technology Paper III: Integrated Control Strategy of Automobile Chassis Electronic Control System
Abstract: The electronic control system of automobile chassis plays an extremely important role in the safety and stability of automobile operation, and the realization of integrated control is conducive to improving its performance. This paper introduces the electronic control system of automobile chassis from three aspects: anti-lock braking system, electronic stability program and active suspension system, and then expounds the specific strategies of integrated control of automobile chassis electronic control system from three aspects: distributed integrated control, general decision-making mechanism and control model, hoping to provide some reference for related research work.
Keywords: automobile chassis; Electronic control system; integrated control
Introduction to 0
In recent years, automobile safety accidents that frequently appear in newspapers have caused great impact on society, some of which are caused by human factors and the other by automobile quality problems. Therefore, it is necessary to improve the quality of the car itself, and at the same time strengthen its integration and intelligence in the design of the chassis system to avoid the interference of human factors.
1 electronic control system of automobile chassis
1. 1 ABS anti-lock braking system
In the process of automobile driving, it is very important to control the wheel transmission state. In an emergency, if the wheel drive cannot be controlled in time, it may lead to safety problems. ABS anti-lock braking system can play a very important role in wheel drive control. It transmits the wheel locking signal in time through the sensor installed on the wheel, and the corresponding controller can reduce the oil pressure of the wheel brake cylinder in time after receiving the signal, thus reducing the braking torque. After a period of time, the signal operation is completed and the braking torque can be gradually restored. Controlling the wheels of the car in this way can effectively avoid the problem of uncontrollable or sideslip of the car and ensure the safety of the car.
1.2 ESP electronic stability program
As far as the basic composition of electronic stability program is concerned, it is mainly composed of three systems: accelerated anti-skid control, brake assist and anti-lock braking, which shows obvious comprehensive characteristics. The system mainly transmits and analyzes the information of each part through sensors, and then calculates and issues correct instructions with the help of the internal system to realize the adjustment of the vehicle state and ensure that the vehicle can maintain a balanced motion state. Generally speaking, wheel sensor, steering sensor, lateral throttle and sideslip sensor together form ESP, which can comprehensively monitor the state of each part of the vehicle and control the vehicle according to the corresponding information. This can ensure that the driving process of the car can be kept stable to the greatest extent, and there will be no problems such as rollover, tail flick and deviation.
1.3 ASS active suspension system
The main purpose of suspension system is to achieve shock absorption and ensure the smooth operation of the car. Generally speaking, as a direct generator, active suspension can effectively feedback and control input and output information, and achieve high-quality shock absorption. Its basic requirement is to make the force formed by the actuator consistent with the control signals of other forces, so as to realize better information collection and tracking and provide guarantee for the smooth operation of the automobile. ASS active suspension system has certain control complexity and needs comprehensive judgment in many aspects, mainly involving spring stiffness, tire stiffness, suspension power, suspension quality and road smoothness. Collect and analyze these information, and then get reasonable control instructions. According to the calculation results, the control instructions can be divided into optimal control, predictive control and adaptive control.
2 integrated control of electronic control system of automobile chassis
2. 1 distributed integrated control
Distributed integrated control, according to the situation, is to realize hierarchical control. At the high level, advanced methods and imprecise methods are combined to form a hierarchical control mode, which can realize the separate control and unified management of multiple subsystems. On the one hand, distributed integrated control can maximize the rationality and comprehensiveness of resource integration. On the other hand, distributed integrated control can also realize the communication between different subsystems, and avoid the contradiction or conflict between different subsystems from affecting the overall operation control of the automobile. For the integrated control of electronic control system of automobile chassis, the integrated control of braking and steering is more critical, and it is also directly related to the core control of automobile operation. Through the in-depth study of vehicle braking and steering, it is found that optimal control technology will increase the linear complexity of the system, which is not conducive to the stability and efficiency of the system. In this regard, the author thinks that the corresponding integrated controller can be designed on the basis of MPC through predictive model control, and the AFS system and ESC system can be integrated to achieve the purpose of integrated control. Predictive model control can effectively overcome the interference of uncertain environment and the error of the model itself, and can show very good linearity.
2.2 General judgment mechanism
For the vehicle itself, there are many different systems, and there are some differences between them. The existence of this difference may lead to certain control contradictions when controlling different subsystems, which will have a serious impact on the control of the whole system. Therefore, it is necessary to construct a general judgment mechanism of overall control to straighten out the control relationship of different systems and avoid control conflicts. In the construction of the overall decision-making mechanism, it is necessary to coordinate the control systems according to the actual situation of the automobile, so as to ensure the overall control of the automobile and realize the stable and safe operation control.
2.3 Establish the integrated model of automobile chassis electronic control system.
To realize integrated control, it is necessary to establish an integrated control model first. In the process of establishing a model, it can generally be divided into three steps. First, select and set the model parameters reasonably. Due to the complexity of automotive systems, each microsystem contains many components. In order to make the integrated control model play a practical and efficient control role, it is necessary to set the parameters of each subsystem reasonably to ensure its rationality and reliability and make the integrated control model meet the control requirements. Secondly, according to the determined system parameters, the model simulation can be carried out by collecting and transmitting the relevant operation data of different parts of the automobile system and inputting them into the model for simulation. The corresponding results can be obtained through calculation, and then the calculation results can be judged. If the result exceeds the allowable range, the control measures need to be adjusted to return to the normal range. If the structure is within the allowable range, the control measures are reasonable and can be further optimized. Finally, some real scenes need to be simulated. The integration of electronic control system of automobile chassis is to show good control performance when the automobile encounters actual situation. Therefore, we can preset some actual scenes, convert them into relevant parameters, input them into the model for simulation, and get specific results, so as to judge the actual control performance of the integrated system.
3 Conclusion
The construction of integrated control of automobile chassis electronic control system needs to realize the specific application of integrated control in automobile chassis electronic control system one by one through the definition of automobile chassis electronic control system, the establishment of general judgment mechanism and model simulation, so as to realize the integration of automobile chassis electronic control system and ensure the stability and safety of automobile control.
References:
Yuan Yu, Chen Lin. Research on integrated control strategy of automobile chassis for active safety [J]. Hebei Agricultural Machinery, 20 15 (0 1): 52-53.
[2] Zhang Jinsheng. On integrated control strategy of electric control system of automobile chassis [J]. Southern Agricultural Machinery, 20 15 (08): 37-38.
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