A brake control system and method for trailer RV based on pressure sensor

Abstract

The present invention relates to the field of vehicle safety control technology, and discloses a brake control system and control method for a trailer-type RV based on a pressure sensor. The system includes: a tractor brake signal transmission module, a synchronizer module, and a RV body stability monitoring module. The tractor brake signal transmission module includes pressure sensors arranged in multiple directions and installed at the ball joint connection between the tractor and the RV. The RV body stability monitoring module includes a variety of body state detection sensors distributed on the RV. The present invention flexibly adjusts and distributes the braking force of each wheel of the RV through a synchronizer based on the size and direction of the force felt by the pressure sensor installed in the ball joint connection, which can improve the rollover, swaying, etc. that occur during the braking process of the RV. At the same time, it improves the complicated circuit layout compared to the traditional electric brake method and saves costs.

Description

Technical Field

[0001] The present invention belongs to the field of vehicle engineering and safety control technology, and relates to a brake system for a trailer-type caravan, and in particular to a brake control system and method for a trailer-type caravan based on a pressure sensor. Background Art

[0002] A trailer RV is a vehicle that combines a car and an RV, which can greatly improve people's comfort during the journey. During the driving process of a trailer RV, the braking system is one of the keys to ensure driving safety. Compared with ordinary vehicles, trailer RVs have many safety hazards. The length, height, and weight of a trailer RV are greater than ordinary vehicles, and the inertia when driving is also greater. The braking distance in an emergency is longer, which can easily lead to loss of control or rollover. Therefore, this type of RV has a higher demand for the braking system. The braking system of a trailer RV is mainly a collision brake or an electric brake. The collision brake transmits the braking signal of the tractor through a mechanical connection. The form is traditional and there are certain safety hazards; the electric brake transmits the braking signal of the tractor to the RV through an electrical signal, which strengthens the control of the braking performance but is complex and costly.

[0003] The collision brake system refers to: a hydraulic device is installed at the ball joint connection position connecting the chassis of the two vehicles. When the tractor brakes, the RV hits and squeezes the ball joint connection connected to the front vehicle under the action of inertia, so as to distribute brake fluid to the RV's braking system to achieve the purpose of braking and deceleration.

[0004] The electric brake system needs to be installed between the RV and the tractor and is controlled by a controller on the tractor. When the tractor driver steps on the brake pedal, the controller sends a signal to the electronic brake system, triggering the RV brakes to brake the RV.

[0005] When the trailer RV with the collision brake system brakes the tractor, the RV will hit the ball joint connection due to inertia, resulting in a large braking force for the RV instantly. The RV quickly brakes and slows down and generates a horizontal backward pulling force on the front vehicle. At this time, the front and rear vehicles move back and forth like a spring. When the vehicle with the collision brake system is turning, driving on an S road, or receiving lateral force interference, it is easy to slip, swing, roll over, etc. due to the lack of independent control of each tire. In addition, when this type of RV is driving uphill or reversing downhill, the ball joint is not in place, resulting in unsatisfactory braking effect, which increases the danger of the car during driving. The braking performance of the trailer RV with the electric brake system has good linearity and synchronization, but a synchronizer needs to be installed on the tractor, and there are also major circuit changes and layouts, which are usually more complicated and expensive. Summary of the invention

[0006] Technical purpose: In response to the above technical problems, the present invention proposes a braking control system and method for a trailer RV based on a pressure sensor, which flexibly adjusts and distributes the braking force of each wheel of the RV through a synchronizer according to the size and direction of the force felt by the pressure sensor installed in the ball joint connection, and has certain improvements for rollover, yaw and other situations that occur during braking. At the same time, compared with electric brakes, it improves the complicated circuit layout and saves costs.

[0007] Technical solution: To achieve the above technical objectives, the present invention adopts the following technical solution:

[0008] A brake control system for a trailer-type RV based on a pressure sensor, characterized in that it includes a tractor brake signal transmission module, a synchronizer module and a RV body stability monitoring module, wherein:

[0009] The tractor brake signal transmission module includes multi-positioned pressure sensors installed at the ball joint connection between the tractor and the RV, and the pressure sensors are used to monitor the pressure value between the tractor and the RV;

[0010] The motorhome body stability monitoring module includes a plurality of body state detection sensors distributed on the motorhome, including a yaw angular velocity sensor, a lateral acceleration sensor, a wheel speed sensor and a horizontal gyroscope sensor. The yaw angular velocity sensor is used to measure the yaw angular velocity of the motorhome. The lateral acceleration sensor is used to measure the acceleration of the motorhome in the lateral direction. The wheel speed sensor measures the speed and acceleration of the motorhome by detecting the speed and direction of rotation of the wheels of the motorhome. The horizontal gyroscope sensor measures the posture and rotation angular velocity of the motorhome in the horizontal direction.

[0011] The synchronizer is installed on the RV and is used to calculate the relative movement speed and direction between the tractor and the RV based on the pressure values ​​transmitted by all pressure sensors in the tractor brake signal transmission module and the RV status data measured by the RV body stability monitoring module, and generate an RV brake control signal for controlling the braking of the electromagnetic brakes installed on each wheel of the RV.

[0012] Preferably, the multi-directionally arranged pressure sensors specifically include: a left pressure sensor, a left front pressure sensor, a front pressure sensor, a right front pressure sensor and a right pressure sensor arranged in sequence, the heights of the pressure sensors being consistent and all perpendicular to the ground, the front pressure sensor being perpendicular to the direction in which the vehicle is moving straight ahead, i.e., the X-axis of the vehicle's driving coordinate system, the left pressure sensor and the right pressure sensor being perpendicular to the lateral direction when the vehicle is moving straight ahead, i.e., the Y-axis of the vehicle's driving coordinate system, and adjacent pressure sensors being arranged at an angle of 135°.

[0013] Preferably, the synchronizer includes a pulse width modulator, a microprocessor, a power supply and a relay, wherein the microprocessor is used to receive the braking signal of the tractor and control the output voltage and frequency of the pulse width modulator, thereby controlling the operation of the electromagnetic brake, and is used to detect the working status of the electronic brake through a diagnostic system, find faults and issue an alarm; the power supply is used to provide the electrical energy required by the system, and the relay is used to control the switch of the braking system to realize the opening and closing of the circuit between the brake, the power supply and the PWM.

[0014] A braking control method for a trailer RV based on a pressure sensor includes the following braking process:

[0015] When the tractor driver steps on the brake pedal, the tractor speed decreases, and the RV hits and squeezes the ball joint connection structure connected to the tractor under the action of inertia. At this time, the pressure sensors arranged in multiple positions at the ball joint connection structure judge the relative movement of the two vehicles based on the detected pressure size and direction, generate corresponding pressure signals and transmit them to the synchronizer;

[0016] The RV body stability monitoring module detects the real-time running status of the RV through various body status detection sensors arranged on the RV, and transmits the detected various body status signals to the synchronizer;

[0017] The synchronizer generates a RV brake control signal based on the signals transmitted by the pressure sensor and the RV body stability monitoring module, controls the electromagnetic brakes installed on each wheel of the RV, and realizes electronically controlled braking of the RV wheels.

[0018] Beneficial effects: Due to the adoption of the above technical solution, the present invention has the following beneficial effects:

[0019] The present invention combines the characteristics of both impact brake and electric brake for trailer RVs, overcomes the problem of non-linear motion of traditional impact brakes, and ensures the stability of the trailer RV during braking and S-road driving by monitoring the motion state of the RV, which improves the braking performance and handling stability of the RV to a certain extent. At the same time, compared with electric brakes, the circuit layout is simplified and costs are saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of signal transmission of each module;

[0021] Figure 2 This is a schematic diagram of the general layout;

[0022] Figure 3 It is a schematic diagram of the brake signal transmission module of the tractor;

[0023] Among them, 1-pressure sensor, 2-yaw angular velocity sensor, 3-lateral acceleration sensor, 4-horizontal gyroscope sensor, 5-wheel speed sensor, 6-brake light, 7-brake, 8-synchronizer. DETAILED DESCRIPTION

[0024] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0025] The present invention provides a trailer-type recreational vehicle braking control system based on multi-directionally arranged pressure sensors, comprising a tractor braking signal transmission module, a synchronizer module and a recreational vehicle body stability monitoring module.

[0026] Among them, the tractor brake signal transmission module includes multi-directional pressure sensors, which are installed at the ball joint connection between the two vehicles and connected to the synchronizer installed at the RV end; the pressure sensor is responsible for monitoring the pressure value between the front and rear vehicles. The pressure sensor includes a metal film / elastomer, a resistance strain gauge, a support structure and an output circuit. When the measured pressure acts on the elastomer, the elastomer will undergo a slight deformation, which will cause the resistance value of the resistance strain gauge installed on it to change. This change in resistance value can be detected and measured by the output circuit to obtain the magnitude of the measured pressure. According to the multi-directional arrangement of the pressure sensors at different angles and different positions, the direction of the measured pressure can be obtained. The synchronizer calculates the relative movement speed and direction of movement based on the measured pressure magnitude and direction and generates a RV brake control signal to flexibly control the braking of each wheel of the RV.

[0027] The RV body stability monitoring module includes a yaw rate sensor, a lateral acceleration sensor, a wheel speed sensor, and a horizontal gyroscope sensor, etc., which are connected to the RV end synchronizer through wires to monitor whether the RV body has dangerous conditions such as yaw, side slip, and roll, so as to make subsequent control. The yaw rate sensor calculates the vehicle's yaw rate by measuring the rotation speed of the vehicle around the vertical axis. It usually contains a gyroscope sensor and a microprocessor. The gyroscope sensor will sense the rotation speed of the vehicle around the vertical axis and convert these rotation speeds into electrical signals, and then the microprocessor calculates the vehicle's yaw rate. The lateral acceleration sensor is used to measure the acceleration of the vehicle in the lateral direction. It usually contains an accelerometer sensor and a microprocessor. The accelerometer sensor will sense the acceleration of the vehicle in the lateral direction and convert these accelerations into electrical signals, and then the microprocessor calculates the vehicle's lateral acceleration. The wheel speed sensor measures the speed and acceleration of the vehicle by detecting the speed and direction of wheel rotation. It is usually installed on the wheel and can detect whether the wheel is slipping or skidding. The horizontal gyro sensor can measure the vehicle's attitude and angular velocity in the horizontal direction. It can provide more accurate attitude and angular velocity data to help control vehicle driving. These sensors can provide key monitoring and control functions for vehicle driving safety. By using these sensors, the vehicle's on-board computer can more accurately understand the vehicle's status and take measures to protect the safety of the vehicle and passengers when necessary.

[0028] The synchronizer module includes a pulse width modulator (PWM), a microprocessor, a power supply, a relay, etc. The microprocessor in the synchronizer receives the braking signal of the tractor and controls the output voltage and frequency of the PWM, thereby controlling the operation of the electronic brake / electromagnetic brake. The microprocessor can also detect the working status of the electronic brake through the diagnostic system, find faults and issue an alarm. The power supply in the synchronizer provides the power required by the system. The relay in the synchronizer is used to control the switch of the braking system so that the circuit between the brake, the power supply and the PWM can be opened and closed. The specific braking process is as follows: the driver of the tractor presses the brake pedal, and the pressure size and direction detected by the pressure sensor determine the relative movement of the two vehicles, generate a corresponding tractor braking signal and transmit it to the synchronizer. The synchronizer's microprocessor receives the tractor braking signal and controls the voltage and frequency of the PWM output according to the set braking force and time. The PWM sends a pulse signal to the electronic brake to trigger the operation of the brake. The brake outputs the corresponding current according to the frequency and voltage of its signal, so that the electromagnet generates magnetic force, so that the brake works to achieve braking. When the tractor braking signal at the pressure sensor disappears, the synchronizer will send a release RV brake control signal, and the RV wheels will resume free rotation. Compared with the mechanical-hydraulic control method of the traditional impact brake system, this control method adopts a more flexible mechanical-electrical control method, the braking performance is more reliable, the braking force is easier to adjust, and after connecting to the RV body stability module, the electronic control system can achieve dual control of the RV braking and driving stability, and the braking stability is greatly enhanced. The tractor braking signal of the traditional electric brake system comes from the tractor, and a lengthy circuit is required to connect the tractor and the RV, and the frame and circuit need to be significantly modified. The tractor braking signal of the method of the present invention comes from the ball joint connection, which saves the modification of the tractor frame and the circuit layout between the two vehicles, saving costs.

[0029] like Figure 1 As shown, the system includes a tractor brake signal transmission module, a motorhome body stability monitoring module and a synchronizer, which work together with the braking system to achieve stable and efficient braking of the trailer motorhome. The present invention installs a pressure sensor at the ball joint connection between the tractor and the motorhome, and uses an electromagnetic brake at the motorhome end. The working principle is:

[0030] (1) When the driver of the tractor vehicle steps on the brake pedal, the speed of the tractor vehicle decreases, and the RV hits and squeezes the connecting parts of the two vehicles under the action of inertia. The RV hits and squeezes the ball joint connection structure connected to the tractor vehicle under the action of inertia;

[0031] At this time, the pressure sensors arranged in various positions at the connection point judge the relative movement of the two vehicles based on the detected pressure size and direction, generate corresponding electrical signals, i.e. the tractor braking signal / pressure signal, and transmit them to the synchronizer;

[0032] (2) The RV body stability monitoring module determines whether the RV has rolled over or skidded based on the yaw rate sensor, lateral acceleration sensor, wheel speed sensor, and horizontal gyroscope sensor, and transmits the signal to the synchronizer;

[0033] (3) The synchronizer generates a RV brake control signal based on the signals of (1) and (2), and independently controls the electromagnetic brakes installed on the left and right wheels of the RV, thereby realizing the electric control braking of the RV wheels and maintaining the stability of the RV body.

[0034] (4) When the tractor brake signal at the pressure sensor disappears, the synchronizer sends a control signal to release the RV brake, and the RV wheels resume free rotation.

[0035] The present invention sets multi-directionally arranged pressure sensors at the ball joint connection to detect the relative movement between the tractor and the RV in real time. The synchronizer comprehensively controls the braking force of the electromagnetic brake installed on each wheel of the RV by measuring the size and direction of the pressure, the size of the lateral acceleration and the slip rate, so that the braking process is smoother and more stable.

[0036] like Figure 2 The general layout diagram shown includes a pressure sensor 1 installed at the ball joint connection between the two vehicles, a yaw rate sensor 2, a lateral acceleration sensor 3, a horizontal gyroscope sensor 4, a brake light 6, a synchronizer 8 installed on the RV body, and a wheel speed sensor 5 and an electromagnetic brake 7 installed on the wheels of the RV.

[0037] The synchronizer includes PWM, microprocessor, power supply, relay and other components. Among them, the relay acts as a brake switch. Generally speaking, during the normal driving of the vehicle, the pressure sensor will produce slight vibration and accidental collision; and when the acceleration of the car exceeds 0.2g, people will feel a slight push back. Therefore, in order to ensure the generation of accurate RV brake control signals, ensure braking safety and the comfort of the tractor passengers, the switching threshold of the relay is set to 0.1 times the vehicle weight. When the pressure sensor senses the pressure of 0.1 times the weight of the front vehicle, the relay will connect the brake system to start braking.

[0038] The microprocessor is responsible for processing and analyzing the digital signal received by the synchronizer, calculating the parameters such as the braking force of each wheel through the internal program algorithm, and transmitting it to the brake system through PWM to control the braking:

[0039] Assume that the mass of the tractor is M and the mass of the RV is m. When the braking force of the tractor is F q When The target deceleration is used for braking; after the RV hits the trailer due to inertia, the deceleration of the two vehicles is According to Newton's second law, the pressure at the pressure sensor (i.e. the pressure of the RV on the pressure sensor)

[0040]

[0041] To ensure that the RV is under pressure F ya With its own target braking force Ff, The target deceleration is

[0042]

[0043] Assume that K is the initial default braking coefficient of the synchronizer. ya And K to obtain the target braking force Ff value of the RV.

[0044] KF ya =Ff (3)

[0045] The initial default value of K obtained by solving the above three equations is: At this time, in theory, the tractor will brake at the same target braking deceleration as the RV. On this basis, the synchronizer corrects the target braking force Ff of the left and right wheels of the RV according to parameters such as pressure direction, lateral acceleration and slip rate to obtain the actual braking force value.

[0046] In addition, the synchronizer can manually adjust the braking force and switch threshold. It sets multiple braking force gears (or adopts non-discrete continuously adjustable gears) inside. The user sends an adjustment signal to the synchronizer through the control element (such as a knob or button), and the synchronizer adjusts the output signal according to the signal, thereby adjusting the braking force.

[0047] Pressure sensors arranged in various directions such as Figure 3 As shown, it includes five parts: left, left front, front, right front, and right. The heights of each sensor are consistent and are all perpendicular to the ground. The front pressure sensor is perpendicular to the X-axis of the vehicle's driving coordinate system, the left and right sensors are perpendicular to the Y-axis of the vehicle's driving coordinate system, and adjacent sensors are arranged at an angle of 135°. When the tractor brakes during straight-line driving, it is mainly the front pressure sensor that is under pressure. At this time, the synchronizer generates a RV brake control signal to control the left and right wheels of the RV to brake at the same time and the braking forces on both sides are equal; when the tractor brakes during left turning, it is mainly the right and right front pressure sensors that are under pressure. At this time, the synchronizer generates a RV brake control signal to control the RV to brake, and the left braking force is larger and the right braking force is smaller, and a wheel speed difference occurs between the left and right wheels of the RV, and the right wheel speed is greater than the left wheel speed, so as to realize the left turn of the RV; when the tractor brakes during left turning, it is mainly the right and right front pressure sensors that are under pressure. At this time, the synchronizer generates a RV brake control signal to control the RV to brake, and the right braking force is larger and the left braking force is smaller, and a wheel speed difference occurs between the left and right wheels of the RV, and the left wheel speed is greater than the right wheel speed, so as to realize the right turn of the RV.

[0048] In the RV body stability monitoring module, the center speed v and wheel angular velocity w of the RV wheel are known through sensors such as wheel speed. w and the wheel rolling radius r when there is no ground braking force r0 Under the condition of , the sliding rate formula (1) shows that the sliding rate s of the RV can be calculated to determine whether the RV has slipped; the lateral acceleration sensor is responsible for measuring the rollover of the RV, and the measured value is compared with 0.76g (the rollover threshold of the RV) to determine whether the RV has rolled over.

[0049]

[0050] Whether it is rollover or slip, when the controller detects this condition, the longitudinal power of each wheel can be independently controlled by the synchronizer to ensure the driving stability of the RV.

[0051] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any form, and any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. A brake control system for a trailer RV based on a pressure sensor, characterized in that: It includes a tractor brake signal transmission module, a synchronizer module and a motorhome body stability monitoring module, among which: The tractor brake signal transmission module includes multi-positioned pressure sensors installed at the ball joint connection between the tractor and the RV, and the pressure sensors are used to monitor the pressure value between the tractor and the RV; the multi-positioned pressure sensors specifically include: a left pressure sensor, a left front pressure sensor, a front pressure sensor, a right front pressure sensor and a right pressure sensor arranged in sequence, the heights of the pressure sensors are consistent and all perpendicular to the ground, the front pressure sensor is perpendicular to the direction of the vehicle going straight, that is, the X-axis of the vehicle driving coordinate system, the left pressure sensor and the right pressure sensor are perpendicular to the lateral direction of the vehicle when it is going straight, that is, the Y-axis of the vehicle driving coordinate system, and adjacent pressure sensors are arranged at an angle of 135°; the pressure sensor includes an elastic body, a resistance strain gauge, a support structure and an output circuit, and the change in the resistance value of the resistance strain gauge is detected and measured by the output circuit; The motorhome body stability monitoring module includes a plurality of body state detection sensors distributed on the motorhome, including a yaw angular velocity sensor, a lateral acceleration sensor, a wheel speed sensor and a horizontal gyroscope sensor. The yaw angular velocity sensor is used to measure the yaw angular velocity of the motorhome. The lateral acceleration sensor is used to measure the acceleration of the motorhome in the lateral direction. The wheel speed sensor measures the speed and acceleration of the motorhome by detecting the speed and direction of rotation of the wheels of the motorhome. The horizontal gyroscope sensor measures the posture and rotation angular velocity of the motorhome in the horizontal direction. The synchronizer is installed on the RV and is used to calculate the relative movement speed and movement direction between the tractor and the RV according to the pressure values ​​transmitted by all pressure sensors in the tractor brake signal transmission module and the RV state data measured by the RV body stability monitoring module, and generate a RV brake control signal for controlling the electromagnetic brake installed on each wheel of the RV. The synchronizer includes a pulse width modulator, a microprocessor, a power supply and a relay. The microprocessor processes and analyzes the digital signal received by the synchronizer, calculates the magnitude of the braking force of each wheel, and transmits the pulse width modulator to the brake system to control the braking. The relay is used to control the switch of the brake system to realize the opening and closing of the circuit between the brake and the power supply and the pulse width modulator. The switch threshold of the relay is set to 0.1 times the vehicle weight. The target braking force Ff of the wheels of the RV is determined according to formula (3): Ff=KF ya (3) K represents the initial default braking coefficient of the synchronizer, F ya Indicates the pressure at the pressure sensor; The synchronizer corrects the target braking force of the RV's wheels to obtain an actual braking force value based on the pressure direction, lateral acceleration and slip rate. The slip rate is calculated based on the center speed of the RV's wheels, the wheel angular velocity and the wheel rolling radius when there is no ground braking force.

2. A brake control method for a trailer RV based on a pressure sensor, applied to the system of claim 1, characterized in that: The braking process includes the following: When the tractor driver steps on the brake pedal, the tractor speed decreases, and the RV hits and squeezes the ball joint connection structure connected to the tractor under the action of inertia. At this time, the pressure sensors arranged in multiple positions at the ball joint connection structure judge the relative movement of the two vehicles based on the detected pressure size and direction, generate corresponding pressure signals and transmit them to the synchronizer; The RV body stability monitoring module detects the real-time running status of the RV through various body status detection sensors arranged on the RV, and transmits the detected various body status signals to the synchronizer; The synchronizer generates a RV brake control signal based on the signals transmitted by the pressure sensor and the RV body stability monitoring module, controls the electromagnetic brakes installed on each wheel of the RV, and realizes electronically controlled braking of the RV wheels.

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