Brake System Plausibility Device

The Brake System Plausibility Device (BSPD) is a safety device which is used to indicate and shutdown the power of vehicle when hard braking, over speeding, pedals break or when too much power is delivered from the vehicle’s motor.

COMPONENTS REQUIRED:

· Diode(1N4001)

· Transistor(2N2222,TIP122)

· Supply Voltage:12V

· Capacitor

· PCB mount-to-wire connectors

· Relay(DPDT-12V)

· MOSFET(IRF540)

· LEDs

· Operational Amplifier(LM358)

· Potentiometers

· Resistors

· Thyristor(BT-151)

· Brake Pressure Sensor(PX3AG1GH010BXAAX)

· Haul Effect Sensor(L06400S05)

HOW DOES IT WORK?

BSPD is powered by 12V battery. The potentiometer is used to indicate the position of the brake pedal and a current sensor is used to sense the power delivered from motor. These sensor values are fed to the comparators (LM358). Whenever the brake sensor value and current sensor value are both above the limit that is set by the user using the potentiometer, the transistor Q1 and Q2 gets shorted.

An AND gate of transistors (Q1 and Q2) is made and whenever hard braking and over deliverance of power from motor occurs at the same time, it will provide signal to capacitor (C2) and after delay of 0.5 seconds it will turn on the thyristor which will latch the error signal, and error LED will light up. It will also send an error signal to shutdown, which would cutoff power from the motor.

The error will remain there until the erroneous situation is no longer there and someone has reset the circuitry.

In a similar way whenever the value of any of the sensor is below the lower limit set by the user, the error signal will be sent to the thyristor which will latch the error protocol again.

The error will also get latched if power to any of the sensor get shorted or cuts down.

When a fault is detected by BSPD, the cockpit reset button must be pressed to restore the supply to the rest of the system after removing the implausibility.

LED D3 is turned on when a fault is detected by the BSPD, otherwise LED D2 is turned on, indicating power supply to shutdown circuit, as shown on PCB.

ORDERING PCB:

Once the PCB design is ready, the user can now order the PCB’s.

For that, the user just has to go to JLCPCB.com, and click on the “QUOTE NOW” button.

JLCPCB has sponsored this project.

JLCPCB (Shenzhen JLC Electronics Co., Ltd.) is the largest PCB prototype enterprise in China and a high-tech manufacturer specializing in quick PCB prototype and small-batch PCB production. One can order a minimum of 5 PCBs for just $2.

1. To get the PCB manufactured, extract the Gerber file from the PCB design software.

2. Upload the Gerber files on the JLCPCB website.

3. After uploading the zip file, a success message would be seen at the bottom if the file is successfully uploaded.

4. The PCB can be reviewed in the Gerber viewer to make sure everything is good.

5. Both the top and bottom of the PCB can be viewed.

6. After making sure the PCB looks good, order can be placed at a reasonable price.

7. One can order 5 PCBs for just $2 but if it’s the 1st order then you can get 10 PCBs for $2.

8. To place the order, click on the “SAVE TO CART” button.

My PCBs took 2 days to get manufactured and arrived within a week using the DHL delivery option. PCBs were well packed, and the quality was really good.

REFERENCES: Formula Student Rules 2020

EV6.1.2

The shutdown circuit is defined as a series connection of at least two master switches, three shutdown buttons, the BOTS, see T6.2, the IMD, the inertia switch, see T11.5, the BSPD, see T11.6, all required interlocks and the AMS.

T11.6.1

A standalone non-programmable circuit, the BSPD, must open the shutdown circuit, see
EV6.1 and CV4.1, when hard braking occurs, whilst
• [EV ONLY] _5kW power is delivered to the motors.
• [CV ONLY] the throttle position is more than 25% over idle position.
The shutdown circuit must remain open until power cycling the LVMS or the BSPD may reset itself if the opening condition is no longer present for more than 10 s.

T11.6.2

The action of opening the shutdown circuit must occur if the implausibility is persistent for more than 500 ms.

T11.6.3

The BSPD must be directly supplied from the LVMS.

T11.6.5

To detect hard braking, a brake system pressure sensor must be used. The threshold must be chosen such that there are no locked wheels and the brake pressure is 30bar.

T11.6.6

[EV ONLY] To measure power delivery, a DC circuit current sensor only must be used. The threshold must be chosen to an equivalent of 5kW for maximum TS voltage.