KR102707622B1 - 4-Point Seat Belt Active Control System for Fire Trucks - Google Patents

Abstract

The active control system for a four-point seat belt for a fire truck according to the present invention comprises a control system for controlling a four-point seat belt including a left belt section for restraining the left shoulder of a passenger seated in a seat of a fire truck, a left drive motor for providing retraction and extraction driving force of the left belt section, a right belt section for restraining the right shoulder of a passenger seated in a seat of the fire truck, and a right drive motor for providing retraction and extraction driving force of the right belt section, the control system including a vehicle information collection section for collecting operation-related information generated from operation information monitoring means equipped in a fire truck, a data analysis section for analyzing the posture of the fire truck based on the operation-related information collected by the vehicle information collection section to derive posture state information and a belt control command, and a motor control section for controlling at least one of the left drive motor and the right drive motor based on the belt control command.

Description

{4-Point Seat Belt Active Control System for Fire Trucks}

The present invention relates to an active control system for a four-point seat belt for a fire truck, and more specifically, to an active control system for a four-point seat belt for a fire truck that can improve the safety of passengers by recognizing the state of the vehicle during operation of the fire truck and controlling the tension of the four-point seat belt.

Fire trucks are driven in emergency situations by nature, so they often maintain a high-speed driving state, and the vehicle's attitude often changes drastically in situations such as sudden braking and turning.

Therefore, fire trucks need to be equipped with various safety devices to ensure the safety of passengers on board.

Seat belts, one of the safety devices installed in existing fire trucks, are generally three-point seat belts, and in some cases, a PSB (Pre-Safe Seat Belt) is applied, which is controlled so that the seat belt automatically pulls the passenger's body in the event of sudden braking, sharp turns, or collisions of the fire truck.

However, since firefighters riding in fire trucks wear a variety of equipment, it is often inconvenient to install seat belts because there is not enough extra length.

In addition, since the three-point seat belt only restrains one shoulder of the passenger, there is a problem that safety is greatly reduced because the unrestrained shoulder on the other side can come off in an unexpected situation such as sudden braking, sharp turns, or collisions.

Therefore, a method to solve these problems is required.

Korean Patent Publication No. 10-2014-0076368

The present invention has been made to solve the problems of the above-described prior art, and has the purpose of providing a four-point seat belt active control system for a fire truck, which applies a four-point seat belt to a seat of a fire truck and controls the tension of the four-point seat belt by recognizing various vehicle states during the operation of the fire truck, thereby improving the safety of the passengers.

The tasks of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the description below.

In order to achieve the above object, the present invention provides a four-point seat belt active control system for a fire truck, comprising: a left belt section for restraining the left shoulder of a passenger seated in a seat of a fire truck; a left drive motor for providing retraction and extraction driving force of the left belt section; a right belt section for restraining the right shoulder of a passenger seated in a seat of a fire truck; and a right drive motor for providing retraction and extraction driving force of the right belt section. The system comprises: a vehicle information collection section for collecting operation-related information generated from operation information monitoring means provided in a fire truck; a data analysis section for analyzing the posture of the fire truck based on the operation-related information collected by the vehicle information collection section to derive posture state information and a belt control command; and a motor control section for controlling at least one of the left drive motor and the right drive motor based on the belt control command.

At this time, the driving information monitoring means may include at least one of a vehicle speed sensor that measures the speed of the vehicle, a first pedal position sensor that measures an accelerator pedal input value of the fire truck, a second pedal position sensor that measures a brake pedal input value of the fire truck, a forward collision avoidance assistance device that detects a forward collision of the fire truck and controls the brake pedal, a body attitude control device that detects skidding of the fire truck and controls the brake pedal and engine output, and a lane departure warning device that detects that the fire truck departs from its lane.

And the vehicle information collection unit can collect the driving-related information through the steps of collecting monitoring data of a fire truck generated from the driving information monitoring means via CAN communication, verifying the reliability of the monitoring data, separating monitoring data that has passed the reliability verification among the monitoring data, and storing the separated monitoring data in memory as the driving-related information.

In addition, the data analysis unit can derive the belt control command through a step of receiving the driving-related information transmitted from the vehicle information collection unit, a step of analyzing the posture of the fire truck from the driving-related information, a step of deriving the posture state information through the analyzed posture of the fire truck, and a step of generating the belt control command based on the posture state information.

In addition, the motor control unit can perform control of at least one of the left drive motor and the right drive motor through a step of receiving the belt control command transmitted from the data analysis unit, a step of setting a target drive motor and a drive speed based on the belt control command, a step of setting a drive time interval based on the belt control command, and a step of controlling a drive motor corresponding to the setting.

Meanwhile, if the data analysis unit derives a state in which the fire truck is tilted to the left as the detailed state information, a belt control command can be derived to control the right drive motor in the forward direction so that the right belt section is retracted while stopping the left drive motor.

In addition, when the data analysis unit derives a state in which the fire truck is tilted to the right as the detailed state information, a belt control command can be derived to control the left drive motor in the forward direction so that the left belt section is retracted while stopping the right drive motor.

And, if the data analysis unit derives a state in which the fire truck is overturned as the detailed state information, a belt control command can be derived to simultaneously control the left drive motor and the right drive motor in the forward direction so that the left belt part and the right belt part are retracted and then stopped.

In addition, if the data analysis unit derives an emergency braking state of the fire truck as the detailed state information, a belt control command can be derived to simultaneously control the left drive motor and the right drive motor in the forward direction so that the left belt part and the right belt part are retracted and then stopped, and if the data analysis unit derives a stabilization state of the fire truck as the detailed state information, a belt control command can be derived to simultaneously control the left drive motor and the right drive motor in the reverse direction so that the left belt part and the right belt part are withdrawn.

In addition, when the data analysis unit derives the stopped state of the fire truck as the detailed state information, after a preset elapsed time has elapsed, a belt control command can be derived to simultaneously control the left drive motor and the right drive motor in the forward direction so that the left belt part and the right belt part are retracted for a preset duration, and then simultaneously control the left drive motor and the right drive motor in the reverse direction so that the left belt part and the right belt part are re-extracted by a preset reference length.

The active control system for a four-point seat belt for a fire truck of the present invention for solving the above-mentioned problem has the advantage of being able to easily maintain the body balance of the passenger by analyzing various postures during the operation of the fire truck, deriving posture status information and belt control commands, and then individually adjusting the tension of the left belt portion and the right belt portion of the four-point seat belt.

In addition, the present invention has the advantage of being able to quickly respond to changes in the posture of a fire truck and control a four-point seat belt to prevent occupants from leaving the fire truck when a collision accident occurs or a situation of overturning or sudden braking occurs in the fire truck, thereby reducing injuries to occupants and greatly improving safety.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

Figure 1 is a drawing showing a four-point seat belt applied to a fire truck.
FIG. 2 is a diagram conceptually illustrating each component of a four-point seat belt active control system for a fire truck according to one embodiment of the present invention.
FIG. 3 is a drawing exemplarily showing the types of driving information monitoring means in a four-point seat belt active control system for a fire truck according to one embodiment of the present invention.
FIG. 4 is a drawing sequentially showing the process of collecting driving-related information by a vehicle information collection unit in a four-point seat belt active control system for a fire truck according to one embodiment of the present invention.
FIG. 5 is a drawing sequentially showing a process of deriving a belt control command by a data analysis unit in a four-point seat belt active control system for a fire truck according to one embodiment of the present invention.
FIG. 6 is a drawing sequentially showing a drive motor control process of a motor control unit in a four-point seat belt active control system for a fire truck according to one embodiment of the present invention.

In this specification, when a component (or region, layer, portion, etc.) is referred to as being "on," "connected to," or "coupled to" another component, it means that it can be directly disposed/connected/coupled to the other component, or that a third component may be disposed between them.

Identical drawing symbols refer to identical components. Also, in the drawings, the thicknesses, proportions, and dimensions of the components are exaggerated for the purpose of effectively explaining the technical contents.

“And/or” includes any combination of one or more of the associated constructs that can be defined.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are only used to distinguish one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. The singular expression includes the plural expression unless the context clearly indicates otherwise.

Additionally, terms such as "below," "lower," "above," and "upper," are used to describe the relationships between components depicted in the drawings. These terms are relative concepts and are described based on the directions indicated in the drawings.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In addition, terms that are defined in commonly used dictionaries, such as terms, should be interpreted as having a meaning consistent with the meaning in the context of the relevant art, and are explicitly defined herein, unless interpreted in an idealized or overly formal sense.

It should be understood that the terms "include" or "have" are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, Fig. 1 is a drawing showing a four-point seat belt (10) applied to a fire truck.

As shown in Fig. 1, a four-point seat belt (10) is applied to the seat of a fire truck to which an active control system according to the present invention is applied.

A four-point seat belt (10) of this type includes a left belt portion (11a) that restrains the left shoulder of a passenger seated in a fire truck, a left drive motor (12a) that provides the driving force for pulling in and pulling out the left belt portion (11a), a right belt portion (11b) that restrains the right shoulder of a passenger seated in a fire truck, and a right drive motor (12b) that provides the driving force for pulling in and pulling out the right belt portion (11b).

That is, unlike the conventional 3-point seat belt (10), the 4-point seat belt (10) is designed so that the left belt portion (11a) and the right belt portion (11b) are symmetrical to each other so that both shoulders of the passenger can be restrained.

And FIG. 2 is a drawing conceptually illustrating each component of a four-point seat belt active control system for a fire truck according to one embodiment of the present invention.

As illustrated in FIG. 2, a four-point seat belt active control system for a fire truck according to one embodiment of the present invention includes a vehicle information collection unit (100), a data analysis unit (200), and a motor control unit (300).

The vehicle information collection unit (100) is configured to collect driving-related information generated from driving information monitoring means equipped in fire trucks.

At this time, the means for monitoring driving information may be various configurations that enable the identification of a specific state of the vehicle or assist in the operation of the vehicle.

FIG. 3 is a drawing exemplarily showing the types of driving information monitoring means in a four-point seat belt active control system for a fire truck according to one embodiment of the present invention.

As illustrated in FIG. 3, the driving information monitoring means may include measuring means for determining the vehicle status, such as a vehicle speed sensor for measuring the speed of the vehicle, a first pedal position sensor for measuring an accelerator pedal input value of the fire truck, and a second pedal position sensor for measuring a brake pedal input value of the fire truck.

In addition, the driving information monitoring means may include driving assistance means that assist the driving of the vehicle, such as a forward collision avoidance assistance device that detects a frontal collision of the fire truck and controls the brake pedal, a body attitude control device that detects skidding of the fire truck and controls the brake pedal and engine output, and a lane departure warning device that detects a fire truck departing from its lane.

It goes without saying that the means for monitoring operational information may include various other components provided in a fire truck in addition to the components exemplarily listed in Fig. 3.

Referring again to FIG. 2, the data analysis unit (200) is configured to analyze the posture of a fire truck based on the driving-related information collected by the vehicle information collection unit (100) and derive posture status information and a belt control command.

That is, the data analysis unit (200) can analyze operation-related information to derive posture status information regarding the posture of a fire truck while in operation, such as whether driving/stopping, speed, acceleration, three-axis inclination, turning status, collision, rollover, and sudden braking.

In addition, the data analysis unit (200) can analyze and derive a belt control command on how to control the 4-point seat belt (10) to safely secure the passenger's body based on such posture information.

And the belt control command derived accordingly is transmitted to the motor control unit (300).

The motor control unit (300) controls at least one of the left drive motor (12a) and the right drive motor (12b) of the four-point seat belt (10) based on the belt control command described above.

That is, the motor control unit (300) selects a drive motor to be driven and a drive speed among the left drive motor (12a) and the right drive motor (12b) according to the belt control command, and sets and controls the drive time interval, thereby enabling the introduction/withdrawal of at least one of the left belt part (11a) and the right belt part (11b).

Below, we will explain the algorithms performed in each of the components described above.

FIG. 4 is a drawing sequentially showing the process of collecting driving-related information by a vehicle information collection unit (100) in a four-point seat belt active control system for a fire truck according to one embodiment of the present invention.

As illustrated in Fig. 4, the process of collecting driving-related information by the vehicle information collection unit (100) may include multiple processes.

First, the vehicle information collection unit (100) collects monitoring data of fire trucks generated from driving information monitoring means through CAN communication.

Then, the vehicle information collection unit (100) verifies the reliability of the monitoring data collected in this manner, and then extracts and separates only the monitoring data that has passed the reliability verification among the monitoring data.

Afterwards, the vehicle information collection unit (100) passes the reliability verification and stores separately separated monitoring data in memory as driving-related information.

Through processes such as the above, operation-related information can be collected.

FIG. 5 is a drawing sequentially showing the process of deriving a belt control command by a data analysis unit (200) in a four-point seat belt active control system for a fire truck according to one embodiment of the present invention.

As illustrated in Fig. 5, the process of deriving a belt control command by the data analysis unit (200) may also include multiple processes.

First, the data analysis unit (200) receives driving-related information transmitted from the vehicle information collection unit (100).

And the data analysis unit (200) analyzes the posture of the fire truck in real time from the received operation-related information, and derives posture status information through the analyzed posture of the fire truck.

In addition, the data analysis unit (200) generates a belt control command based on the derived detailed state information.

Through processes such as the above, detailed state information and belt control commands can be generated.

FIG. 6 is a drawing sequentially showing the drive motor control process of the motor control unit (300) in a four-point seat belt active control system for a fire truck according to one embodiment of the present invention.

As illustrated in Fig. 6, the process of controlling at least one of the left drive motor (12a) and the right drive motor (12b) by the motor control unit (300) is performed as follows.

First, the motor control unit (300) receives a belt control command transmitted from the data analysis unit (200).

And, based on the received belt control command, the motor control unit (300) sets the target drive motor to be controlled among the left drive motor (12a) and the right drive motor (12b) and sets the driving speed thereof.

In addition, the motor control unit (300) sets the driving time interval of the target driving motor based on the received belt control command.

And according to the above settings, the motor control unit (300) controls the corresponding driving motor to perform the introduction/withdrawal of at least one of the left belt unit (11a) and the right belt unit (11b).

Meanwhile, according to the detailed state information derived by the data analysis unit (200), the belt control command derives the control logic of various motor control units (300), and the control logic of the belt control command derived according to the detailed state information will be described below.

First, if the data analysis unit (200) derives the state of the fire truck tilting to the left as detailed state information, there is a possibility that the passenger's right shoulder will come off the seat.

Accordingly, in such a case, the data analysis unit (200) can derive a belt control command that stops the left drive motor (12a) of the four-point seat belt (10) and controls the right drive motor (12b) in the forward direction so that the right belt part (11b) is drawn in.

Conversely, if the data analysis unit (200) derives the state of the fire truck tilting to the right as detailed state information, there is a possibility that the passenger's left shoulder will come off the seat.

Accordingly, in such a case, the data analysis unit (200) can derive a belt control command that stops the right drive motor (12b) of the four-point seat belt (10) and controls the left drive motor (12a) in the forward direction so that the left belt part (11a) is drawn in.

Meanwhile, the process in which the motor control unit (300) controls the left drive motor (12a) or the right drive motor (12b) to pull in the left belt section (11a) or the right belt section (11b) according to each belt control command derived from the tilted state of the fire truck as described above can be subdivided into a method in which the process of drive control - drive stop is alternately repeated n times in a short period of time.

This is to perform real-time control corresponding to real-time changes in the inclination of the fire truck, since the inclination of the fire truck can continuously change even during the process in which the motor control unit (300) introduces the left belt unit (11a) or the right belt unit (11b).

For example, the data analysis unit (200) can derive a sum vector by synthesizing the vectors of each of the three-axis tilt angles of the fire truck collected by the vehicle information collection unit (100).

And the data analysis unit (200) can determine which section of the multiple preset slope sections the result value of the sum vector belongs to, and derive a belt control command to control the left drive motor (12a) or the right drive motor (12b) at a driving speed corresponding to the corresponding slope section.

Accordingly, the motor control unit (300) can receive an updated belt control command from the data analysis unit (200) in real time during the process of alternately performing the drive control - drive stop process n times in a short period of time, and control the left drive motor (12a) or the right drive motor (12b) according to the corresponding belt control command during the drive control process immediately thereafter.

And by repeating this process, the motor control unit (300) can control the inlet speed of the left belt unit (11a) or the right belt unit (11b) in real time to correspond to the real-time inclination change of the fire truck.

Next, if the data analysis unit (200) derives the state of the fire truck overturning as detailed state information, there is a possibility that the entire body of the passenger may be separated from the seat.

Accordingly, in such a case, the data analysis unit (200) derives a belt control command that simultaneously controls the left drive motor (12a) and the right drive motor (!2b) in the forward direction so that the left belt portion (11a) and the right belt portion (11b) of the four-point seat belt (10) are pulled in and the state is continuously maintained.

In addition, if the data analysis unit (200) derives the emergency braking state of the fire truck as detailed state information, there is a possibility that the passenger's entire body may be removed from the seat.

In such a case, the data analysis unit (200) first derives a belt control command that simultaneously controls the left drive motor (12a) and the right drive motor (12b) in the forward direction so that the left belt part (11a) and the right belt part (11b) are introduced and then stopped.

However, if the left belt part (11a) and the right belt part (11b) are maintained in the retracted state even after the emergency braking state of the fire truck has ended, there is a possibility that strong pressure will be continuously applied to the passenger's body, resulting in injury.

Accordingly, when the data analysis unit (200) derives the stable state of the fire truck as the detailed state information after the emergency braking state of the fire truck, a belt control command is derived to simultaneously control the left drive motor (12a) and the right drive motor (12b) in the reverse direction so that the left belt part (11a) and the right belt part (11b) are pulled out, thereby relieving the pressure applied to the passenger's body.

In addition, when the data analysis unit (200) derives the stopped state of the fire truck as detailed state information, it is necessary to prevent a situation in which the left belt section (11a) and the right belt section (11b) are not properly inserted when the passenger releases the 4-point seat belt (10).

Accordingly, in such a case, the data analysis unit (200) can simultaneously control the left drive motor (12a) and the right drive motor (12b) in the forward direction so that the left belt part (11a) and the right belt part (12b) are drawn in for a preset duration after a preset elapsed time has elapsed from the time when the stopped state of the fire truck is derived.

In addition, the data analysis unit (200) can derive a belt control command that simultaneously controls the left drive motor (12a) and the right drive motor (12b) in reverse direction so that the left belt part (11a) and the right belt part (11b) are retracted by a preset reference length when the left belt part (11a) and the right belt part (11b) are fully retracted. This is to release the locking state of the left belt part (11a) and the right belt part (11b).

And then the data analysis unit (200) can enter power saving mode.

As described above, preferred embodiments according to the present invention have been examined, and it is obvious to those skilled in the art that the present invention can be embodied in other specific forms in addition to the embodiments described above without departing from the spirit or scope thereof. Therefore, the above-described embodiments should be considered as illustrative rather than restrictive, and accordingly, the present invention is not limited to the above description, but may be modified within the scope of the appended claims and their equivalents.

10: 4-point seat belt
11a: Left belt
11b: Right belt
12a: Left drive motor
12b: Right drive motor
100: Vehicle Information Collection Department
200: Data Analysis Department
300: Motor control unit

Claims (10)

A control system for controlling a four-point seat belt, comprising a left belt section for restraining the left shoulder of a passenger seated in a seat of a fire truck, a left drive motor for providing retraction and withdrawal driving force for the left belt section, a right belt section for restraining the right shoulder of a passenger seated in a seat of a fire truck, and a right drive motor for providing retraction and withdrawal driving force for the right belt section,
A vehicle information collection unit that collects operation-related information generated from operation information monitoring devices equipped on fire trucks;
A data analysis unit that analyzes the posture of a fire truck based on the driving-related information collected by the vehicle information collection unit and derives posture status information and belt control commands; and
A motor control unit that controls at least one of the left drive motor and the right drive motor based on the belt control command;
Including,

If the above data analysis unit derives a state in which the fire truck is tilted to the left based on the detailed state information,
With the left drive motor stopped, a belt control command is derived to control the right drive motor in the forward direction so that the right belt section is introduced.

If the above data analysis unit derives the state in which the fire truck is tilted to the right based on the detailed state information,
With the right drive motor stopped, a belt control command is generated to control the left drive motor in the forward direction so that the left belt section is introduced.

The process of controlling the left drive motor or the right drive motor to pull in the left belt section or the right belt section according to each belt control command derived from the state where the fire truck is tilted to the left or right is as follows:
The above data analysis unit synthesizes the vectors of each of the three-axis tilt angles of the fire truck collected by the vehicle information collection unit to derive a sum vector, and then determines which section of the multiple preset tilt sections the result value of the sum vector belongs to, and derives a belt control command to control the left drive motor or the right drive motor at a driving speed corresponding to the corresponding tilt section.
The above motor control unit alternately performs the process of drive control - drive stop for the target controlled by the belt control command among the left drive motor or the right drive motor, n times for a preset time.
During the driving stop state, the updated belt control command is transmitted in real time from the data analysis unit, and the left or right driving motor is controlled according to the belt control command during the driving control process immediately thereafter.
Controlling the inlet speed of the left belt section or the right belt section in real time to respond to real-time inclination changes of the fire truck.

Active control system for 4-point seat belts for fire trucks. In the first paragraph,
The above operation information monitoring means is,
A speed sensor that measures the speed of a vehicle;
A first pedal position sensor that measures the accelerator pedal input value of a fire truck;
A second pedal position sensor that measures the brake pedal input value of a fire truck;
Forward collision avoidance assist device that detects a frontal collision of a fire truck and controls the brake pedal;
A body attitude control device that detects skidding of a fire truck and controls the brake pedal and engine output; and
Lane departure warning system that detects when a fire truck departs its lane;
Containing at least one of the following:
Active control system for 4-point seat belts for fire trucks. In the first paragraph,
The above vehicle information collection unit,
A step of collecting monitoring data of a fire truck generated from the above-mentioned operation information monitoring means through CAN communication;
A step of verifying the reliability of the above monitoring data;
A step of separating monitoring data that has passed reliability verification from the above monitoring data; and
A step of storing separated monitoring data in memory as the above operation-related information;
Collecting the above operation-related information through
Active control system for 4-point seat belts for fire trucks. In the first paragraph,
The above data analysis department,
A step of receiving the driving-related information transmitted from the vehicle information collection unit;
A step of analyzing the posture of a fire truck from the above operation-related information;
A step of deriving the posture status information through the posture of the analyzed fire truck; and
A step of generating the belt control command based on the above detailed state information;
Deriving the above belt control command through,
Active control system for 4-point seat belts for fire trucks. In the first paragraph,
The above motor control unit,
A step of receiving the belt control command transmitted from the data analysis unit;
A step of setting a target drive motor and drive speed based on the above belt control command;
A step of setting a driving time interval based on the above belt control command; and
A step of controlling a driving motor corresponding to the setting;
Controlling at least one of the left driving motor and the right driving motor through
Active control system for 4-point seat belts for fire trucks. delete delete In the first paragraph,
If the above data analysis unit derives the state in which the fire truck has overturned based on the detailed status information,
A belt control command is derived to simultaneously control the left drive motor and the right drive motor in the forward direction so that the left belt part and the right belt part are stopped after being introduced.
Active control system for 4-point seat belts for fire trucks. In the first paragraph,
If the above data analysis unit derives the emergency braking status of the fire truck using the detailed status information,
A belt control command is derived to simultaneously control the left drive motor and the right drive motor in the forward direction so that the left belt part and the right belt part are stopped after being introduced.
Afterwards, if the data analysis unit derives the stabilization status of the fire truck using the detailed status information,
A belt control command is derived to simultaneously control the left drive motor and the right drive motor in reverse so that the left belt portion and the right belt portion are pulled out.
Active control system for 4-point seat belts for fire trucks. In the first paragraph,
If the above data analysis unit derives the stopped state of the fire truck using the detailed status information,
After the preset elapsed time has elapsed, the left drive motor and the right drive motor are simultaneously controlled in the forward direction so that the left belt part and the right belt part are introduced for the preset duration,
A belt control command is derived to simultaneously control the left drive motor and the right drive motor in reverse so that the left belt portion and the right belt portion are re-drawn by a preset standard length.
Active control system for 4-point seat belts for fire trucks.