CN114088418B - Multifunctional intelligent detection and diagnosis integrated equipment for automobile chassis - Google Patents

Abstract

The invention discloses multifunctional intelligent detection and diagnosis integrated equipment for an automobile chassis, which comprises the following contents: A. a weight identification method is adopted to confirm whether wheels reach or leave a detection position, B, a method of self-moving a vehicle body at a low speed without driving and correcting is adopted, C, a separated remote control pedal switch for brake detection is adopted; D. the method comprises the following steps of (1) adopting a device and a method for quickly stopping wheels from laterally striking an upright post back and forth, E adopting a low-speed indirect detection method for measuring deceleration to detect parking braking force, F adopting a method for obtaining braking coordination time and confirming whether the braking coordination time is emergency braking or point braking according to the change characteristics of a braking deceleration curve: the invention has the advantages of large cost performance, double reduction of detection workshops and occupied areas of automobile detection enterprises, land resource saving, great investment saving, contribution to reduction of detection charge, less occupied automobile detection area and more convenience in handling automobile detection business by an automobile owner.

Description

Multifunctional intelligent detection and diagnosis integrated equipment for automobile chassis

Technical Field

The invention relates to automobile chassis detection equipment, in particular to a counter-force type roller braking inspection bench, an axle weight instrument, a speedometer inspection bench, an inertial type roller braking inspection bench and a remote control pedal switch special for automobile braking.

Background

The existing professional automobile detection line is generally provided with three detection devices, namely a counter-force type roller brake inspection bench (hereinafter referred to as a counter-force bench), a shaft weight instrument and a speedometer inspection bench, wherein the counter-force type roller brake inspection bench is used for detecting the maximum braking force of each wheel of an automobile, and judging whether the braking force reaches the standard or not according to the load of each axle; the axle weight instrument is used for weighing the load of each axle of the automobile and providing data matching for the counter-force table; the speedometer inspection bench is used for detecting whether the automobile speedometer meets the standard.

1. The volume and the weight of the three devices are large, but the detection content is very small, because the detection technology is too late, for example, a counter-force table is used for detecting the maximum braking force of the wheels theoretically, but the wheels slide on the roller, so that only the approaching value of the maximum braking force can be actually detected, and the value is obviously smaller than the maximum braking force; the speed of the counter-force table drum is more than 2km/h, such as the same speed as the scattering speed, and the difference between the speed and the running braking speed of the automobile and the working condition of the counter-force table drum is too large, so that the braking effect is not real, the existing automobile is provided with an ABS system for improving the braking efficiency and the braking safety, the ABS system does not work at all in the state that the speed is less than 20 km/h, and if the counter-force table is used for detecting the braking performance of the automobile, the brake detection is neither real nor significant, and the brake detection is that the weight of the automobile is the same, so that the authenticity, the rationality and the necessity of the whole automobile detection are indistinct.

2. The inertial roller braking inspection bench (hereinafter referred to as inertial bench) can detect the braking distance of the automobile at any speed, the working principle is that the rotational kinetic energy of the load roller and the flywheel simulates the running kinetic energy of the automobile on the road, and if the automobiles with different weights can realize the simulation, the braking inspection (including ABS braking) reproduces the braking process of the automobile on the road, so that the automobile is very vivid. Since the last sixties of the century, the inertial table has many problems restricting the use of the inertial table, and has not been popularized yet, and the inertial table has the main problems of (1) serious noise generated by high-speed detection, (2) easy lateral sliding of wheels on a roller rotating at high speed; (3) no remote pedal switch adapted for brake detection; (4) and the field safety problem of high-speed detection.

3. The special automobile detection line is provided with a computer for controlling each detection device, instrument and detection process, so that digital display and automatic detection of a single flow are realized, but no intelligent detection concept exists so far, and the three devices are not more than four detection contents in total because of the lag of detection technology and few detection contents, so that the detection line can not become a reference for basic technical performance of an automobile chassis, and can not become a diagnosis basis for analyzing and judging technical faults of the chassis. In addition, the diagnosis of the automobile chassis is a matter of the automobile maintenance industry, is not related to the automobile detection industry, the current automobile chassis diagnosis technology level is behind the engine diagnosis, the chassis is not disassembled to be checked, analyzed and judged by virtue of the traditional diagnosis instrument and the technical experience of people, the whole process is manually operated, and the diagnosis conclusion is determined by people, namely, the diagnosis accuracy is poor and the working efficiency is low.

Disclosure of Invention

Aiming at the problems existing in the prior art, the invention comprehensively upgrades the technical performance of the purchased inertia platform, improves some hardware structures, adopts new detection and control technology and computer software, increases a large amount of detection contents, and increases the detection contents from the braking force, wheel weighing, speedometer and other detection contents of the three devices to twenty-two items, thereby obtaining a large amount of and abundant detection data, and the inertia platform becomes multifunctional intelligent detection and diagnosis integrated equipment for the automobile chassis by adding a carefully developed computer software system.

The invention is realized in the following way:

the multifunctional intelligent automobile detection and diagnosis integrated equipment comprises the following contents: A. a weight identification method is adopted to automatically confirm whether the wheels arrive or leave the detection position, and the front wheels and the rear wheels are distinguished automatically so as not to be afraid of interference; B. c, adopting a separated remote control pedal switch for brake detection, wherein a steel plate is fixed on a long tail clamp, a bakelite plate and a movable contact piece are riveted on the steel plate, a fixed contact is riveted on the bakelite plate, the movable contact piece is not contacted with the fixed contact at ordinary times, namely, the switch is switched off, the fixed contact is pressed after being stepped on, the pedal switch is connected with a remote control transmitter by a wire, the pedal switch is clamped on the brake pedal before the brake pedal is stepped on, the remote control transmitter is held on the hand or placed above an instrument board, the pedal switch is stepped on firstly when the brake pedal is stepped on, so that the brake pedal is electrically connected, a signal is transmitted by the remote control transmitter through the wire, and the original button of the remote control transmitter can be used for speedometer detection; d. A device and a method for quickly stopping wheels from laterally striking the upright posts are adopted, wherein the middle section of four cross beams for installing a large roller is respectively provided with an upright post, a raised upright small roller is arranged on the upright post, the pin hole of a pin seat on the small roller is a slightly tapered round hole, the pin hole of the lower pin seat is a waist round hole, the hole wall of the pin seat is provided with a transverse spring hole provided with a spring, the side of the pin head below the small roller is provided with a micro switch, the spring is pressed against the pin head below the small roller outwards at ordinary times, the lower part of the small roller protrudes outwards than the upper part of the small roller, the wheels strike the pin head below the small roller against the waist round hole wall on the side of the spring, meanwhile, the micro switch is pressed to send out signals, no matter which upright post is firstly struck by the wheels, the motor is controlled to be immediately powered off and the flywheel is completely plucked, the large roller loses power and most of rotational kinetic energy can be stopped very quickly, at the moment, the large roller is allowed to be stopped immediately, thereby the wheels are rapidly struck against the upright post, the small roller is pressed against the side, a measured and the upright post is struck, a low-speed indirect detection method is used for detecting braking force, and a self-coordination braking time and a parking braking point are obtained according to the change characteristic of a braking curve: the speed reducing curve difference between emergency braking and point braking is large, the computer counts and stores the encoder pulse with a counting period of 0.03s per unit time before braking, which is the initial speed of braking, and simultaneously numbers and stores the period numbers sequentially for each counting period, the computer starts timing when the brake pedal is pressed, which is a remote control pedal switch, and simultaneously captures that the counting of the counting period is continuously performed twice before x pulses are less than the previous period, which is equivalent to the speed reducing rate of more than 4m/ss, and takes the time of the period with the first x pulses as the inflection point and stores the inflection point and the code; the time from the depression of the brake pedal to the inflection point is the brake coordination time, if the point brake is performed, the rapid deceleration of which the counting period is less than the previous period by more than x pulses does not occur continuously, the inflection point code and the brake coordination time are not generated, and the computer can automatically confirm whether the emergency brake or the point brake is performed according to the existence of the inflection point code.

The invention aims to solve the technical problems:

1. first solve the problem that inertial table exists: 1. the serious noise of high-speed detection is caused by using a sleeve roller chain for transmission, and the noise is small after the sleeve roller chain is changed into a tooth-shaped chain; 2. when the vehicle body is detected at a high speed, as long as the longitudinal axis of the vehicle body is not parallel to the longitudinal axis of the detection equipment, the wheels can easily slide laterally on the roller rotating at the high speed, so that the detection cannot be performed; 3. a separated remote control pedal switch for brake detection is adopted, wherein a steel plate is fixed on a long tail clamp, a bakelite plate and a movable contact are riveted on the steel plate, a fixed contact is riveted on the bakelite plate, the movable contact is not contacted with the fixed contact at ordinary times, namely, the switch is disconnected, the switch is connected after being stepped on and pressed against the fixed contact, the pedal switch is connected with a remote control transmitter through a wire, before the brake pedal is stepped on, the pedal switch is clamped on the brake pedal, the remote control transmitter is held on the hand or placed above an instrument board, when the brake pedal is stepped on, the pedal switch is firstly stepped on to form electric connection, a signal is transmitted through the wire connection remote control transmitter, and the original button of the remote control transmitter can be used for speedometer detection; 4. the invention adopts a device and a method for quickly stopping wheels from laterally striking the upright posts back and forth, wherein the middle section of four cross beams for installing a large roller is respectively provided with an upright post, the upright post is provided with a raised upright small roller, the pin hole of a pin seat on the small roller is a slightly tapered round hole, the pin hole of the lower pin seat is a waist round hole, the hole wall is provided with a transverse spring hole for installing a spring, the side of the pin head below the small roller is provided with a micro switch, the spring is propped against the pin head below the small roller outwards at ordinary times, so that the lower part of the small roller protrudes outwards than the upper part, the wheels strike the pin head below the small roller against the waist round hole wall on the side of the spring, meanwhile, the micro switch is pressed to send out a signal, no matter which upright post is firstly struck by the wheels, the motor is controlled to be powered off immediately, all flywheels are taken off, the large roller loses power and most of rotational kinetic energy can stop immediately, and the large roller is allowed to step on the brake to stop immediately, so that the wheels are quickly stopped from striking the upright posts back and forth.

2. The detection content of the invention is increased to twenty two items, namely wheel weighing, braking distance, braking deceleration curve graph, braking force, parking braking force, braking coordination time, braking duration time, braking force balance, braking gap rate, braking initial speed, braking rolling distance, braking sliding rate, point braking deceleration, point braking gap rate, point braking deceleration curve graph, vehicle speed, speedometer, sliding distance, sliding time and acceleration time, wherein a low-speed indirect detection method for measuring deceleration is adopted to detect the parking braking force. The braking in the twenty-two terms is emergency braking as long as no point of care braking or parking braking exists.

3. The invention relies on software technology to embody intelligent detection: (1) all detection contents can be detected singly, and a plurality of common detection contents can be optimally combined to form full-automatic running water detection; (2) the weight recognition method is adopted to automatically confirm whether the wheels arrive or leave the detection position or not, and the front wheels and the rear wheels are automatically distinguished so as not to be afraid of interference; (4) in one detection operation, detection of a plurality of detection contents can be finished at the same time, so that the working efficiency is improved; (5) completing one detection content, and obtaining several detection results simultaneously; (6) the method for obtaining the braking coordination time and self-confirming whether emergency braking or point braking is carried out according to the change characteristics of a braking deceleration curve is adopted: the speed reducing curve difference between emergency braking and point braking is large, the computer counts and stores the encoder pulse with a counting period of 0.03s per unit time before braking, which is the initial speed of braking, and simultaneously numbers and stores the period numbers sequentially for each counting period, the computer starts timing when the brake pedal is pressed, which is a remote control pedal switch, and simultaneously captures that the counting of the counting period is continuously performed twice before x pulses are less than the previous period, which is equivalent to the speed reducing rate of more than 4m/ss, and takes the time of the period with the first x pulses as the inflection point and stores the inflection point and the code; the time from the depression of the brake pedal to the inflection point is the brake coordination time, if the point brake is performed, the rapid deceleration of which the counting period is less than the previous period by more than x pulses does not occur continuously, the inflection point code and the brake coordination time are not generated, and the computer can automatically confirm whether the emergency brake or the point brake is performed according to the existence of the inflection point code.

4. The invention forms a large amount of detection data with abundant detection content, provides enough data support for a computer expert diagnosis system, thereby having the capability of intelligent diagnosis of the chassis and completing detection and diagnosis once, and provides a chassis diagnosis report for a vehicle owner while submitting a vehicle inspection report for a vehicle management department, thereby realizing multifunctional intelligent detection and diagnosis integration of the chassis of the vehicle.

The beneficial effects of the invention are as follows: the vehicle is detected on the intelligent detection and diagnosis integrated equipment of the automobile chassis, namely the road test detection of the vehicle is reproduced, so that all detection data are more true and accurate; the invention has advanced detection technology, more detection content and intelligent detection, and some practical detection items such as sliding, point braking and the like can be easily completed without relying on road test detection; the intelligent detection and diagnosis of the chassis are integrated and completed at one time, so that the operation efficiency of the chassis diagnosis can be greatly improved, the chassis diagnosis becomes quick, accurate and convenient, and the high-level technical service of 'chassis diagnosis report' can be provided during annual inspection of the vehicle, so that a vehicle owner can know the condition of the vehicle, and the vehicle is beneficial to reducing the running of the vehicle with diseases; the multifunctional automobile inspection system can replace a plurality of traditional inspection devices, has great cost performance advantage, reduces the inspection workshops and occupied area of the automobile inspection enterprises in multiple times, reduces the land used outside the inspection workshops, saves land resources, saves a large amount of investment for the automobile inspection enterprises, is beneficial to reducing inspection charges, is beneficial to people and attracts automobile sources, and is more convenient for car owners to transact automobile inspection services because the automobile inspection enterprises occupy less land and are not far away from urban areas. In a word, the invention has good popularization prospect.

Drawings

FIG. 1 is a schematic diagram of a separate remote pedal switch;

FIG. 2 is a schematic diagram of a device for quickly stopping a person on a wheel from striking a column back and forth sideways;

fig. 3 is a deceleration graph for emergency braking and point braking.

In the figure: 1. the steel plate 2, the bakelite plate 3, the movable contact 4, the fixed contact 5, the copper rivet 6, the long tail clamp 7, the small roller 8, the upper pin seat 9, the lower pin seat 10, the spring hole 11, the micro switch 12, the emergency braking deceleration curve 13, the point braking deceleration curve 14, the emergency braking deceleration inflection point 15, the upright post 16, the spring 17, the wire 18 and the remote control transmitter.

Detailed Description

The invention is described in detail below with reference to the attached drawings and embodiments:

1. first solve the problem that inertial table exists: 1. the serious noise of high-speed detection is caused by using a sleeve roller chain for transmission, the rotating speed of a chain wheel exceeds 1500rpm to generate harsher noise similar to an anti-air alarm, and the noise is larger when the rotating speed is higher, so that the noise is very small after the sleeve roller chain is changed into a tooth-shaped chain (silent chain); 2. when the vehicle body is detected at high speed, the wheels are easy to slide laterally on a roller rotating at high speed as long as the longitudinal axis of the vehicle body is not parallel to the longitudinal axis of the detection equipment, the swinging vehicle is inclined or the rotating speed is higher, the lateral sliding speed and inertia are higher, so that the detection cannot be carried out; 3. the automobile brake pedal for detecting the inertia type emergency brake or point brake needs to be provided with a remote control pedal switch, and signals are emitted when the automobile brake pedal is stepped on, the pedal switch is required to be thin and light without influencing the foot feeling of stepping on the brake, cannot be sensitive to avoid misemission, is convenient to use and is firm and durable, because the emergency brake requires to step on the brake pedal to the bottom in a fierce way, the pedaling force of the foot is more than 200N, the remote control pedal switch which can be used only by buying is damaged in a plurality of times, hundreds of yuan is not available, and aiming at the situation, the invention self-creates the separated remote control pedal switch: A steel plate 1 serving as a switch base is fixed on a long tail clamp 6, as shown in fig. 1, the steel plate 1, a bakelite plate 2 and a movable contact piece 3 are riveted together by copper rivets 5, the movable contact piece 3 is a thicker and well-elastic 201 stainless steel plate, a row of copper rivets are riveted on the bakelite plate to serve as a fixed contact 4, the movable contact piece 3 is not contacted with the fixed contact 4, namely, a switch is turned off, the fixed contact 4 is pressed after being stepped on, the movable contact piece 3 is uniformly stressed and is not easy to deform when being pressed on a row of fixed contacts 4 with the same height, thus the pedal is firm and resistant to being stepped on, the pedal switch is clamped on a brake pedal by a wire 17 for connecting a remote control emitter 18, the remote control emitter 18 is held on a hand or placed above an instrument board, the brake pedal is stepped on necessarily to be first on to form an electric connection, a signal is transmitted by a wire 17, and an original button of the remote control emitter 18 can be used for detecting a speedometer or other detecting, and the remote control pedal switch is thin and light. The use is very convenient, the service life is longer than thousands times, and the cost is only tens of yuan; 4. In case of accident. The stable state of the vehicle body after the vehicle body is righted is damaged, and the coaxial wheels can quickly sideslip to a certain side on the large roller rotating at a high speed. After striking the upright post on the side, the elastic force of the tire adds rebound inertia, and slides to the other side rapidly, namely continuously strikes the upright post back and forth, so that the detection site becomes very dangerous, and the motor is overloaded when stepping on the brake, because all detection except the brake do not need to remotely control a pedal switch, the motor can not be controlled to be powered off when stepping on the brake by transmitting a signal, the power supply of the motor can be cut off by only needing to get up to the shout, then the rotary kinetic energy of the roller and the flywheel is consumed when stepping on the brake to finish the back and forth striking, and the workers on the site are busy. Some detection devices such as chassis dynamometer, insert spacing post outside the wheel that targets in place manually, pull out after detecting again, be used for limiting the range of striking back and forth, but can't solve the cause of striking back and forth of wheel and stop the problem as soon as possible, on the contrary because more manual intervention becomes the technology and backs up, to this situation, the invention has self-created device and method of stopping wheel side direction striking back and forth fast: the invention installs a column 15 in the middle section of four crossbeams of the big cylinder, can prevent the wheel from sliding out of big cylinder laterally, install a vertical small cylinder 7 protruding from column 15 in the trough of every column 15, as shown in figure 2, the wheel rotated bumps up and will be blocked by small cylinder 7 and rotates with it, the pin hole of the pin seat 8 on small cylinder 7 is a slightly tapered round hole, the pin hole of the pin seat 9 is a waist round hole and there is a transverse spring hole 10 loading the spring 16 on the hole wall, small cylinder 7 is located between upper, lower pin seat, the lower pin head of small cylinder 7 is equipped with the micro-gap switch 11, the spring 16 is propped against the lower pin head of small cylinder 7 outwards at ordinary times, make small cylinder 7 incline somewhat, namely the lower side is more protruding outwards than the upper side, the wheel bumps up and hits down under small cylinder 7, make the round hole wall of the lower pin head compression spring 16 lean against this side of spring namely small cylinder 7 become vertical by tilting, at the same time micro-gap switch 11 sends out the signal, no matter which column 15 has automatic signal to bump up and off the motor, the flywheel is stopped rapidly and lost the big cylinder is stopped rapidly, the high-speed and the rotation of the column is stopped immediately, the high-speed and the high-speed brake is stopped, the method is favorable for the field safety of high-speed detection.

2. Solves the problems existing in the inertial table, and opens the door for the application of inertial detection: the inertial table is provided with a lifting weighing mechanism, so that a shaft weight instrument can be omitted; if a new detection technology is adopted, not only the speedometer inspection bench can be replaced, but also the braking coordination time, the braking duration, the initial speed and the final speed of braking, the braking deceleration curve of braking and a coordinate diagram (see figure 3) can be drawn, the braking deceleration can be obtained, and the braking force can be obtained by the deceleration and the axle weight obtained by weighing the previous wheels; the sliding is a free deceleration process without stepping on the brake, and the addition of the sliding detection content is very useful for chassis diagnosis; the inertia table is provided with a third roller for measuring the rolling distance during braking, and the sliding distance and the braking slip rate can be obtained by the braking distance and the rolling distance, which are main technical indexes for evaluating the ABS braking performance; the traditional parking braking force detection is carried out under a parking state (static state), the inertia type detection is carried out except weighing, all detection contents can be carried out in wheel rotation (dynamic state), and aiming at the problem, the invention self-creates a low-speed indirect detection method for measuring deceleration to detect the parking braking force, namely, when a motor is automatically powered off after a roller is accelerated to a rated rotation speed, the roller and wheels are freely decelerated to a lower vehicle speed of 15-14.5 km/h by inertia, a driver rapidly pulls a hand brake rod to the bottom to generate hand brake deceleration according to a large screen image prompt, the hand brake rod is decelerated to a 12km/h computer to start timing, the vehicle speed is just zero to stop timing, the timing time is the deceleration time, then the operation is 12/3.6 = the axle deceleration, and the axle parking braking force = the axle load is multiplied by the axle deceleration according to Newton's law F = ma; the twenty-two items of detection content of the invention are as follows: wheel weighing, braking distance, braking deceleration graph, braking force, parking braking force, braking coordination time, braking duration, braking force balance, braking gap rate, braking initial speed, braking rolling distance, braking sliding rate, point braking deceleration, point braking gap rate, point braking deceleration graph, vehicle speed, speedometer, sliding distance, sliding time and acceleration time.

3. The intelligent detection is embodied by means of software technology: (1) all detection contents can be detected singly, and a plurality of common detection contents can be optimally combined to form full-automatic running water detection, namely, the whole process is controlled by a computer to form self-compensation and self-correction capability of sampling signals, a large-screen image displays the in-place and out-of-place of a vehicle wheel, dynamically displays the speed and various prompts of the vehicle, and each node of detection operation has the prompt; if the weight of the front wheel is larger than y but smaller than 2 seconds, the front wheel is driven to pass through and is not stopped, the computer memorizes the front wheel load q, the next perceived weight=q+/-2%, if the weight of the front wheel is still the front wheel, otherwise, the rear wheel is the rear wheel, and the condition that the perceived weight is larger than y for 2 seconds continuously is confirmed, so that the vehicle wheel can be confirmed to be in place and the front wheel and the rear wheel can be distinguished; (3) the vehicle body can be righted while the vehicle in place can be automatically moved by the vehicle body when the image is prompted without driving and righting, so that the high-speed detection operation is more efficient and safer; (4) in one detection operation, detection of a plurality of detection contents can be finished simultaneously, so that the working efficiency is improved, for example, detection of sliding and parking braking can be finished simultaneously; (5) and (6) a method for obtaining the braking coordination time and self-confirming whether the emergency braking or the point braking is carried out according to the change characteristics of a braking deceleration curve is self-created, and the detection operation effect which is wanted by people is obtained: the emergency braking is to stop as soon as possible, the point braking is to run at a reduced speed, the driving can be influenced by the phenomenon that the emergency braking is not deviated and the point braking is deviated, the driving safety is influenced, the number of times of using the point braking is much more than that of the emergency braking, and the point braking detection is necessary; the emergency braking is to suddenly apply the maximum braking force to the wheels to rapidly decelerate the wheels after stepping on the feet, the feet are loosened after stopping, the slope of the braking overall process is about 2s, as shown in fig. 3, the braking deceleration curve of the emergency braking is obviously changed from the flat-inclined emergency braking deceleration inflection point 14 to the action starting point of the maximum braking force, the point braking is to step on the braking pedal, the feet are loosened after the vehicle is decelerated, the vehicle continues to run, the slope of the deceleration curve is smaller, and the difference between the emergency braking deceleration curve 12 and the point braking deceleration curve 13 is very large. The invention multiplies the pulse count obtained in each unit time, for example, 0.03s, by a certain coefficient to represent the speed of the vehicle, the ordinate of figure 3 is the speed of the vehicle, the unit is 0.1 km/h, the abscissa is the time, the unit is 0.03s, the speed of each 0.03s is taken as a coordinate point on the graph, the points are connected to form a braking deceleration curve, curves with different colors represent front, back, left and right different wheels, the computer starts counting and storing the encoder pulses with a counting period of each unit time from the speed of the vehicle being slightly higher than the initial speed of the brake, namely before the brake, and sequentially numbering each counting period and storing the period numbers, the computer starts timing by pressing a brake pedal, namely, a remote control pedal switch, simultaneously captures the time when the counting period is x pulses less than the previous period, namely, the time corresponding to the deceleration is more than 4m/ss, and takes the time when the emergency period is x pulses less than the first time as the braking inflection point and the braking code; the time from the depression of the brake pedal to the inflection point is the brake coordination time, if the point brake is performed, the rapid deceleration of which the counting period is less than the previous period by more than x pulses does not occur continuously, the inflection point code and the brake coordination time are not generated, and the computer can automatically confirm whether the emergency brake or the point brake is performed according to the existence of the inflection point code.

4. The large quantity of abundant detection contents form detection big data, and enough data support is provided for a computer expert diagnosis system, so that the intelligent diagnosis capability of a chassis is provided, the detection and diagnosis are completed at one time, the multifunctional intelligent detection and diagnosis integration is realized, and the chassis diagnosis report which can be understood by a vehicle owner is automatically provided while the vehicle inspection report is automatically submitted to a vehicle management department, for example: (1) the detection data reflect that the braking distance and the braking duration of the right front wheel of the automobile are not up to the standard, and the chassis diagnosis report indicates the bad phenomenon that the automobile is biased leftwards during braking and indicates the reason that the gap between a brake friction plate of the right front wheel and a brake disc is large or the contact area is small; if the braking coordination time does not reach the standard, a reason is that the piston of the right front wheel cylinder is inflexible or the leather cup expands, the oil pipe is shrunken or air is introduced; (2) the detection data reflect that the sliding distance of the left rear wheel of the automobile does not reach the standard, and the chassis diagnosis report indicates that the left rear wheel has large wheel rotating resistance and indicates that the left rear wheel bearing has poor quality; the tire is under-inflated. The computer expert diagnosis system of the invention is to seat the unqualified detection data and the expert opinion database by itself, integrate the selected expert opinion into a chassis diagnosis report, and the expert opinion database is based on the content of the transplanted automobile maintenance professional teaching material, the present content is less, but new diagnosis content proved by a large number of experiments can be added at any time to perfect the system, so as to achieve the integration of intelligent chassis detection and diagnosis at a higher level.

Claims (1)

1. The multifunctional intelligent detection and diagnosis method for the automobile chassis is characterized by comprising the following steps of: the method comprises the following steps: a, adopting a weight identification method to automatically confirm whether the wheels arrive or leave the detection position, and distinguishing the front wheels and the rear wheels by self so as not to be afraid of interference; and B, adopting a method of self-moving and correcting the car body at a low speed without driving and correcting, so that wheels at high speed detection cannot slide laterally on the roller: before detection, the roller drives the wheels to slowly rotate for ten seconds at a speed of 2km/h, the slow-rotating lateral sliding speed and inertia are very small, when the lateral sliding acting force reaches the conditions that the left wheel and the right wheel are equal in size and opposite in direction, namely are bilaterally symmetrical, sliding is stopped, the vehicle body is also automatically moved right, and then no matter how high the rotating speed is, the axial position of the wheels on the roller is not changed, so that the high-speed detection site is safer; a separated remote control pedal switch for brake detection is adopted, wherein a steel plate (1) is fixed on a long tail clamp (6), a bakelite plate (2) and a movable contact piece (3) are riveted on the steel plate, the movable contact piece is a 201 stainless steel plate with good elasticity, a row of copper rivets are riveted on the bakelite plate to serve as a fixed contact (4), the movable contact piece is not contacted with the fixed contact at ordinary times, namely, the switch is turned off, the fixed contact is pressed after the movable contact is stepped on, the switch is connected with a remote control transmitter (18) through a wire (17), before a brake pedal is stepped on, the pedal switch is clamped on the brake pedal, the remote control transmitter is held on the hand or placed above an instrument board, the pedal switch is stepped on firstly when the brake pedal is stepped on, the pedal switch is electrically turned on, a signal is transmitted through the wire, and the original button of the remote control transmitter is used for speedometer detection; and D, adopting a method for rapidly stopping wheels from laterally striking the upright post back and forth: the middle sections of four cross beams for mounting the large roller are respectively provided with a stand column (15), the stand column is provided with a protruding vertical small roller (7), the pin hole of a pin seat (8) on the small roller is a small taper round hole, the pin hole of a lower pin seat (9) is a waist round hole, the hole wall is provided with a transverse spring hole (10) provided with a spring (16), the side of a pin head below the small roller is provided with a micro switch (11), the spring is propped against the pin head below the small roller outwards at ordinary times, so that the lower part of the small roller protrudes outwards than the upper part of the small roller, the wheel bumps against the waist round hole wall on the side of the spring, meanwhile, the micro switch is pressed to send out a signal, no matter which stand column is firstly bumped by the wheel, the motor is controlled to be immediately powered off and all flywheels are picked off, the large roller loses power and most of rotational kinetic energy can stop rapidly, and the large roller is allowed to be stepped on to stop immediately, so that the wheel is prevented from being bumped laterally and backwards and forwards; and E, detecting the parking braking force by adopting a low-speed indirect detection method for measuring the deceleration: when the motor is automatically powered off after the drum accelerates to the rated rotation speed, and the drum and wheels freely decelerate to the speed of 15-14.5 km/h by virtue of inertia, a driver rapidly pulls a hand brake rod to the bottom according to a large screen image prompt, so as to generate hand brake deceleration, the hand brake is decelerated to 12km/h, a computer starts timing, the speed is just zero, the timing is the deceleration time, then the calculation is carried out, namely 12/deceleration time/3.6 = the axle deceleration, and the axle parking braking force = the axle load x the axle deceleration according to Newton's law F = ma; F. the method for obtaining the braking coordination time and self-confirming whether the emergency braking or the point braking is carried out according to the change characteristics of the braking deceleration curve comprises the following steps: the speed reduction curve difference between emergency braking and point braking is large, the computer counts and stores the encoder pulse by taking a specified unit time as a counting period before braking, and simultaneously numbers and stores each counting period in sequence, the computer starts timing when a signal is sent out by a remote control pedal switch which is a brake pedal is pressed down, and simultaneously captures that the counting of the counting period is continuously performed twice before the counting period is more than x pulses which are more than the previous period and is more than 4m/s2 of deceleration, and takes the time of the period which is more than x pulses at the first time as an inflection point (14) and stores the inflection point; the time from the depression of the brake pedal to the inflection point is the brake coordination time, if the point brake is performed, the rapid deceleration of which the counting period is less than the previous period by more than x pulses does not occur continuously, the inflection point and the brake coordination time are not present, and the computer can automatically confirm whether the emergency brake or the point brake is performed according to the presence or absence of the inflection point.