JP2005241632A - Detector of load on seat - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely determine a load in case that a wrong incorporation occurs at the time of incorporating a plurality of load sensors to a seat. <P>SOLUTION: This detector comprises a plurality of load sensors 21, 22, 23 and 24 generating output signals according to the load acting on the seat 1, signal processing circuits 31, 32, 33 and 34 adding unique IDs to the output signals to output load signals, and a control device 25 performing seating determination of the seat 1 based on the load signals. The control circuit 25 determines and stores port alignments corresponding to the signal processing circuits based on the unique IDs, and performs the seating determination by the load value outputted by each signal processing circuit. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a load detection device on a seat, and in particular, a port between a load detection device including a plurality of load sensors and a control device that performs seating determination based on loads detected by the load sensors. This relates to an on-seat load detection device that performs initial setting.

  2. Description of the Related Art Conventionally, an air bag apparatus has been widely used in order to reliably protect a seated person sitting on a seat at the time of a car collision. From the viewpoint of safety, it is determined whether the seated person is an adult or a child, and the operation of the airbag is restricted or the amount of inflation of the airbag is changed according to the result. That is, accurate determination of a seated person (whether an adult or a child) is very important.

  Therefore, conventionally, a load sensor is provided between the seat and the seat support member that supports the seat with respect to the vehicle interior floor, and the weight (load) of the seated person is detected. In order to accurately detect the weight of the seated person, four load sensors are provided on the front and rear of the seating surface of the seat (for example, Patent Document 1).

In general, inexpensive pressure film sensors and strain gauges are often used as load sensors. The signal (load signal) output by these is relatively small. For this reason, in order to transmit a load signal, which is a small output, to a control device disposed at a position away from the load sensor, for example, under the seat, the load signal must be amplified. Therefore, a signal processing circuit is provided in the vicinity of the load sensor to amplify the load signal and to suppress and remove signal noise and transmit it to the control device.
Japanese Patent Laid-Open No. 2002-240613 (see FIG. 4)

  Usually, the load acting on the seat by the seated person is not uniform, and therefore the load received by the load sensor is not uniform. In order to reduce costs, considering the load distribution on the front and back of the seating surface of the seat, load sensors for high loads are used on the left and right rear sides of the seating surface where a relatively large load is applied, and a small load is applied. A load sensor for low load is used on the left and right front sides of the seating surface of the seat. As described above, different load sensor characteristics are used before and after, but it is preferable that the shape of the load sensor itself be the same in terms of cost.

  In the sheet production line, an operator is performing a flow operation, and load sensors having the same shape but different sensor characteristics are attached to predetermined positions of the sheet. Therefore, an operator may assemble the load sensor at an incorrect position instead of a regular position. As a result, an incorrect load signal from the load sensor is input to the control device, and the control device cannot accurately determine the seated person.

  In general, a connector is provided between a control device and a signal processing circuit electrically connected. If ribs are individually provided for each connector, erroneous assembly of the load sensor by an operator can be prevented. However, if the connector is provided with ribs, an increase in cost is inevitable.

  Therefore, the present invention has been made in view of the above problems, and when assembling a plurality of load sensors on a seat, it is possible to accurately determine a seated person even if there is an erroneous assembly. , Is the issue.

  The technical means taken to solve the above-described problems each generate an output signal corresponding to the load acting on the seat, and are provided in each of the load sensors having different characteristics and the load sensors, A signal processing circuit that outputs a load signal by adding a unique ID corresponding to the load sensor to the output signal, and a port for inputting the load signal, and performs seating determination based on the load signal In the on-seat load detection apparatus including the control unit, the control unit determines a port arrangement for the signal processing circuit corresponding to the unique ID.

  Preferably, at the time of initial setting of the control means, there is provided a setting device that is electrically connected to the control means and determines the port arrangement.

  The control means may include a memory for storing the port arrangement, and the port arrangement stored in the memory at the time of initial setting may be rewritten.

  According to the first aspect of the present invention, each signal processing circuit of the load sensor adds a unique ID to the output signal of the load sensor and transmits it as a load signal to the control means. The control means can determine which signal processing circuit the port of the control means is connected to based on the unique ID included in the load signal. Therefore, even when the load sensor and the signal processing circuit are erroneously assembled to the control unit, the control unit can change the port arrangement based on the unique ID and perform accurate seating determination.

  According to the second aspect of the present invention, when the control means is initially set, the port arrangement can be determined by electrically connecting the setting device to the control means and issuing an initial setting request from the setting device. Since the setting device only needs to be connected to the control means at the time of initial setting, it can be a general-purpose device that can be detached from the control means. This can be reused in factories and the like.

  According to the invention of claim 3, the control means can store the port array corresponding to the unique ID in the memory, and the port array can be rewritten at the initial setting. Even when the load sensor is incorrectly assembled, the seating can be accurately determined by the control means.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing a seat body (hereinafter referred to as a seat) 1 of a vehicle seat, and FIG. 2 is a diagram in which load sensors 21, 22, 23, 24 of a seat load detection device 20 are attached to the seat 1. Indicates the state.

  In the seat 1, a pair of left and right support frames 2 with respect to the floor surface 11 are installed in the vehicle front-rear direction (x direction). A pair of front and rear brackets 3 are fixed to the upper surfaces of the left and right support frames 2, and a lower rail 4 is fixed to the pair of front and rear brackets 3 along the support frame 2. The pair of left and right lower rails 4 has a U-shaped cross section and opens upward, and the opening forms a slide groove 5 extending in the x direction.

  In the slide groove 5, a pair of left and right upper rails 6 are respectively slidable along the slide groove 5 in the x direction. As shown in FIG. 2, the upper rail 6 has a lower arm 16 that supports a seat cushion 9 and a seat back 10 at a predetermined interval via a pair of left and right front sensor brackets 7 and a rear sensor bracket 8. It is connected.

  As shown in FIG. 3A, the front sensor bracket 7 has an upper fastening portion 7a and a lower fastening portion 7b at both upper and lower ends, and the upper and lower fastening portions 7a, 7b are pressed by press working. It bends and the bending part 7c is formed in the meantime. In the front sensor bracket 7, upper and lower fastening portions 7 a and 7 b are connected by fastening members in front of the lower arm 16 and the upper rail 6, respectively. A front right load sensor (FR load sensor) 21 and a front left load sensor (FL load sensor) 22 that constitute a load sensor are provided in the bent portions 7c of the right and left front sensor brackets 7. The FR load sensor 21 and the FL load sensor 22 include an inexpensive strain detection element such as a thick film sensor or a strain gauge, for example, and the bending portion 7c bends due to deformation according to the load acting on the seat cushion 9. The bending amount can be electrically detected by the bending portion 7c.

  On the other hand, as shown in FIG. 3B, the rear sensor bracket 8 has an upper fastening portion 8a and a lower fastening portion 8b at both upper and lower ends, and between the upper and lower fastening portions 8a and 8b. Are bent by press working, and a bent portion 8c is formed therebetween. The rear sensor bracket 8 is connected to the rear side of the lower arm 16 and the upper rail 6 at the upper and lower fastening portions 8a and 8b, respectively. A rear right load sensor (RR load sensor) 23 and a rear left load sensor (RL load sensor) 24 constituting load sensors are provided in the flexure portions 8c of the right and left rear sensor brackets 8, respectively. The RR load sensor 23 and the RL load sensor 24 are provided with an inexpensive strain detection element such as a thick film sensor and a strain gauge, for example, like the above-described FR load sensor 21 and FL load sensor 22. The bending portion 8c bends according to the load acting on, and the bending amount of the bending portion 8c can be electrically detected.

  Next, the configuration of the on-sheet load detection device 20 that detects the load acting on the seat 1 will be described with reference to FIG. Four load sensors 21 to 24 described above are arranged on the front, rear, left and right of the seating surface of the seat 1. The load sensors 21 to 24 detect loads acting on the seating surface of the seat 1 and output analog sensor signals. In the vicinity of the load sensors 21 to 24, signal processing circuits 31 to 34 are integrally provided. The signal processing circuits 31 to 34 form a digital output by adding a noise filter function for suppressing or preventing noise on the load signal, an amplification function for amplifying the amplitude of the load signal, and a unique ID set for each load sensor. An analog-digital conversion function is provided.

  When an occupant sits on the seat 1, the load acting on the seat 1 is not uniform, and the loads received by the load sensors 21 to 24 are not uniform. Considering the load distribution in the front and rear with respect to the seating surface of the seat 1, load sensors 21 and 22 for low loads are used on the left and right front sides of the seating surface on which a relatively small load acts, and a large load acts. Load sensors 23 and 24 for high loads are used on the left and right rear sides of the seating surface of the seat 1. As described above, the load sensors 21 to 24 have different characteristics before and after, but it is preferable that the shapes of the load sensors 21 to 24 are all the same in terms of cost.

  The control device 25 is driven by a battery 35 (for example, 12V) that supplies power to the vehicle, and includes a communication circuit 19 that performs bidirectional communication with the signal processing circuits 31 to 34, a CPU 26, and a constant voltage power source. A power supply circuit 27 that generates (for example, 5 V), an output circuit 28 that provides a signal for restricting the operation to the airbag controller 30, and a communication circuit 29 that performs bidirectional communication with an inspection device 40 described later. Yes. Digital load signals output from the signal processing circuits 31, 33, 34, and 32 are input to the four ports P1, P2, P3, and P4 of the CPU 26 via the communication circuit 19. The constant voltage generated by the power supply circuit 27 is supplied to the CPU 26. The CPU 26 includes a memory (for example, a ROM that stores a program, a RAM that temporarily stores information that is necessary data when the program is executed) and a timer.

  When initializing the control device 25, the tester 40 is electrically connected to the communication circuit 29 of the control device 25. The tester 40 outputs an initial setting request to the CPU 26 of the control device 25 via the communication circuit 29, and rewrites the storage contents preset in the CPU 26 (for example, the arrangement of the ports P1 to P4 of the CPU 26). The initial setting is performed when, for example, the battery 35 is connected to the control device 25 and the power supply to the control device 25 is started, when the initial setting at the time of factory shipment is performed, or when the control device is malfunctioning at a maintenance shop or the like. Or it is performed when the load sensor is replaced.

  On the other hand, the output circuit 28 is connected to an airbag controller 30 that controls the airbag that protects the occupant in the event of a vehicle collision. The CPU 26 determines a seated person on the seat based on the result of the seating determination, and sends the determined information to the airbag controller 30 as a seated person signal. The airbag controller 30 that receives the seated person signal restricts the operation of the airbag depending on whether the seated person is an adult or a child (for example, when an adult is seated, the airbag controller 30 operates the airbag, The operation is prohibited when seated) and the amount of operation of the airbag is variable.

  Next, program processing executed by the CPU 26 will be described with reference to FIG.

  When the key is turned on as the automobile engine starts, the CPU 26 performs an initial process in step S1. In the initial process, memory such as ROM and RAM provided in the CPU is checked, and it is confirmed whether there is any abnormality in the external device connected to the control device 25. Subsequently, in step S2, the presence or absence of a sensor initial setting request is confirmed. That is, it is confirmed whether the tester 40 is connected to the control device 25 within a predetermined period of program execution and an initial setting request is output to the CPU 26. If there is no initial setting request, the process proceeds to step S6, and if there is an initial setting request, the process proceeds to step S3.

  In step S3, the CPU 26 requests the signal processing circuits 31 to 34 to output a load signal including the unique ID. The output load signal is stored in a predetermined memory area in the CPU 26 with the unique ID as a pointer. Ports P1 to P4 of the CPU 26 are assigned to signal processing circuits 31 to 34 corresponding to the load sensors 21 to 24, for example, as shown in FIG.

  That is, the load signal of the signal processing circuit 31 (FR load sensor 21) is provided to the port P1 of the CPU 26, the load signal of the signal processing circuit 33 (RR load sensor 23) is provided to the port P2, and the signal processing circuit 34 (RL load) is provided to the port P3. The load signal of the sensor 24) and the load signal of the signal processing circuit 32 (FL load sensor 22) are input to the port P4. The load signal is composed of 15 bits, one start bit for one frame, two unique ID bits, ten load data bits, one parity bit, and one stop bit.

  Next, in step S4, the CPU 26 acquires a unique ID from each load signal, and confirms the unique ID of the load signal input to each port P1 to P4. In advance, the signal processing circuit 31 corresponding to the FR load sensor 21 corresponds to “unique ID = 1”, the signal processing circuit 32 corresponding to the FL load sensor 22 corresponds to “unique ID = 4”, and corresponds to the RR load sensor 23. The signal processing circuit 33 is assigned “unique ID = 2”, and the signal processing circuit 34 corresponding to the RL load sensor 24 is assigned “unique ID = 3”.

  In step S5, the arrangement of the ports P1 to P4 connected to the signal processing circuits 31 to 34 is determined corresponding to the unique ID included in the load signal. That is, the port connected to the signal processing circuit 31 that outputs the load signal with “unique ID = 1” is connected to the port P1 and the signal processing circuit 33 that outputs the load signal with “unique ID = 2”. A port connected to the port P2 and a signal processing circuit 34 that outputs a load signal with "unique ID = 3" is connected to the port P3, and a signal processing circuit that outputs a load signal with "unique ID = 4" 32 is assigned as port 4. Such port assignment is performed by storing a port array corresponding to the unique ID in advance in the memory of the CPU 26 as shown in FIG.

  After the assignment of the ports P1 to P4 is completed as described above, the CPU 26 requests the signal processing circuits 31 to 34 to output a load signal including a unique ID in step S6. The output load signal is stored in a predetermined memory area in the CPU 26 with the unique ID as a pointer. Thereafter, the total load value is calculated in step S7. That is, the total load value is obtained from the sum of the load data included in each load signal corresponding to each of the four load values detected by the load sensors 21 to 24. Thereafter, in step S8, occupant determination is performed based on the size of the total load value. Note that a filter process is performed in order to exclude load values that deviate greatly. In step S8, if the total load value is equal to or greater than a preset occupant determination threshold value, the seated person on the seat is determined to be “adult” in step S9. On the other hand, if the total load value is less than the preset occupant determination threshold value, the seated person on the seat is determined to be “child” in step S10. After steps S9 and S10, the process returns to step S2, and the CPU 26 repeats the occupant determination process of steps S2 to S10 at a predetermined cycle.

  When the connector between the signal processing circuits 31 to 34 and the control device 25 is not correctly assembled, a port is assigned as shown below in step S5. For example, assume that the connector of the signal processing circuit 31 is connected to the connector of the port P2 shown in FIG. 5, and the connector of the signal processing circuit 33 is connected to the connector of the port P1 shown in FIG. Even in this case, as described above, the CPU 26 assigns ports according to the unique ID. Therefore, the CPU 26 rewrites the port array stored therein as shown in FIG. 6B, and the signal processing circuit 31 (FR load). The load signal from the sensor 21) can be correctly input to the port P1, and the load signal from the signal processing circuit 33 (RR load sensor 23) can be correctly input to the port P2. Thereafter, when the total load value is calculated in step S7, the CPU 26 performs correction according to erroneous assembly of the load sensors 21, 23 related to the signal processing circuits 31, 33.

  As described above, in the present embodiment, the description has been made with the configuration using four load sensors 21 to 24. However, the configuration is not limited to this. It may be done. When the output signals of the load sensors 21 to 24 are large to some extent or noise is difficult to be placed, the noise filter function and the amplification function of the signal processing circuits 31 to 34 are omitted, or the signal processing circuits 31 to 34 are connected to the load sensor 21. It is not necessary to provide it integrally with -24.

  Further, each time the battery 35 is connected to the control device 25 and power is supplied without using the tester 40, an initial setting request is generated and the assignment of the ports P1 to P4 of the CPU 26 is automatically executed. it can.

It is a perspective view of a vehicle seat. It is a block diagram at the time of applying a seat load detection apparatus to the vehicle seat shown in FIG. It is explanatory drawing which showed the shape of the sensor bracket shown in FIG. 2, (a) It is a perspective view of a front side sensor bracket, (b) is a perspective view of a rear side sensor bracket. It is a lineblock diagram of the load detecting device on a sheet in one embodiment of the present invention. It is a flowchart which shows the process which CPU shown in FIG. 4 performs. It is explanatory drawing explaining the matching setting of each port shown in FIG.

Explanation of symbols

1 Sheet body (sheet)
11 Floors 21, 22, 23, 24 Load sensor (load detection device)
25 Control device (control means)
31, 32, 33, 34 Signal processing circuit (load detection device)
40 Inspection device (setting device)
P1, P2, P3, P4 ports

Claims (3)

A plurality of load sensors having different characteristics, each generating an output signal corresponding to the load acting on the seat,
A signal processing circuit that is provided in each of the load sensors and outputs a load signal by adding a unique ID corresponding to the load sensor to the output signal;
In the on-seat load detection device having a port for inputting the load signal, and a control means for performing seating determination of the seat based on the load signal,
The on-seat load detection apparatus according to claim 1, wherein the control means determines a port arrangement for the signal processing circuit in correspondence with the unique ID. The on-seat load detection device according to claim 1, further comprising a setting device that is electrically connected to the control unit and determines the port arrangement when the control unit is initially set. The on-seat load detection device according to claim 1, wherein the control unit has a memory for storing the port arrangement, and rewrites the port arrangement stored in the memory at the time of initial setting.

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