Project 1- Traffic Jam Assistant Feature

Aim: - Development of a single feature of Traffic Jam Model using MATLAB & Simulink.

Objective: -

To develop one specific requirement of Traffic Jam Assistant algorithm which would predominantly feature in the IPC algorithm. (Please note that the whole Traffic Jam Assistant is a very huge algorithm & only one small part of the logic is implemented here. Idea is to familiarize with concepts of Model Based Development in MATLAB Environment. )

• This model must be developed in MATLAB Simulink as per MBD guidelines.
• Code Generation Profile must be in Embedded Coder.
• Simulink Data Dictionary must be created for the model & must be linked to the model.
• Model Advisor Report is mandatory & this will be followed by Code Generation.

Traffic Jam Assistant Feature

Introduction to the Feature:

Traffic Jam Assistant is one of the most common feature in Advanced Driver Assistance System. Traffic Jam Assistant helps the driver arrive more relaxed at their destination, even in dense traffic or in traffic jams. As a partially automated comfort function, the system takes over the longitudinal & lateral guidance of the vehicle. This means that the car can drive off, accelerate & brake automatically, as well as steer the vehicle within certain constraints. The driver has to permanently supervise the system & be ready to take over the complete control of the vehicle at any time.

Traffic Jam Assistant system helps to avoid rear end collisions in dense traffic conditions & traffic jams. In Traffic jams, the vehicle takes over driving off, acceleration, braking and steering within same lane.

Basic Working Principle:

Traffic Jam Assistant is based on the sensors and the functionality of the Adaptive Cruise Control (ACC) with stop & go and Lane Keeping Support (LKS). When ACC ‘Stop & Go’ is turned ON, the Traffic Jam Assistant continuously analyses the speed of the surrounding vehicles and compares it with the own driving speed. If the system detects dense traffic or a traffic jam at speeds less than 60 kmph, the driver can activate the functionality by press of a button. The vehicle will now automatically follow the vehicle in front, takes over driving off, acceleration, braking and steering within same lane.

Information regarding the Traffic Jam Assistant will be available to be displayed to the driver in the Instrument Panel Cluster (IPC). The Algorithm which the students need to implement here in this project is predominantly based on IPC units.

Given Data: -

Input Signals: -

Name of the Signal	Data Type	Range
Input_Voltage	uint8	0 - 255
Input_Switch	boolean	0 – 1
Enable_Display	uint8	0 - 255

Output Signal:

Name of the Signal	Data Type	Range
Output_Display	uint8	0 - 255

Calibration Signals:

Name of the Signal	Data Type	Range	Initial Value
VOLTAGE_MINIMUM_RANGE	uint8	0 – 255	30
VOLTAGE_MAXIMUM_RANGE	uint8	0 – 255	50
OFF_MODE	uint8	0 – 255	2
ON_MODE	uint8	0 – 255	1
STANDBY_MODE	uint8	0 – 255	3
INTERRUPT_1	boolean	0 – 1	1
INTERRUPT_2	boolean	0 - 1	1
NO_DISPLAY	uint8	0 – 255	0

Local Signal:

Name of the Signal	Data Type	Range
Optimum_Voltage	boolean	0 - 1

Requirement No 1:

• Input Signal “Input_Voltage” is compared against voltage values “VOLTAGE_MINIMUM_RANGE” & “VOLTAGE_MAXIMUM_RANGE”.
• Incoming input signal “Input_Voltage” must be greater than – equal to “VOLTAGE_MINIMUM_RANGE” and less than – equal to “VOLTAGE_MAXIMUM_RANGE”.
• Output signal from here is “Optimum_Voltage” which will be one of the inputs to the subsystem “DisplayUnit”.

Requirement No 2 (DisplayUnit Subsystem):

• Input Signals are “Optimum_Voltage”, “Input_Switch”,“Enable_Display”. Signal “Enable_Display” must be saturated between the range 0 – 7. Output signal from the subsystem is “Output_Display”.
• Input Signal “Enable_Display” is compared against pre – defined set of values in a multiport switch. Total data ports in the multiport switch is 5.
• Multiport switch inputs 1 & 2 is connected to calibration signal “ON_MODE”, Multiport switch inputs 3 & 4 is connected to calibration signal “OFF_MODE” while Multiport switch input 5 is connected to calibration signal “STANDBY_MODE”.
• The output from Multiport switch is connected to the first input port of the Switch block. The third input port of the Switch block is connected to the calibration signal “NO_DISPLAY”.
• Meanwhile NOT value of input signal “Input_Switch” is compared in an AND gate against input signal “Optimum_Voltage” and the output from comparing if calibration signals “INTERRUPT_1” & “INTERRUPT_2” are equal. The output of the AND gate is the second input of the switch block.
• The output from the switch block is “Output_Display”.

Discription: -

Traffic Jam model was created in MATLAB Simulink as per MBD guidelines with Main Subsystem called as ' Traffic_jam_assistance_feature' is shown below.

The main Subsystem consist of two sub systems they are

a) Requirement_1

b) Requirement_2

a) Requirement_1 :-

The simulink Blocks of simulink model in Requirement_1 were created as per the given data Requirement 1. Here, the Input Signal “Input_Voltage” is compared against voltage values “VOLTAGE_MINIMUM_RANGE” & “VOLTAGE_MAXIMUM_RANGE” and Output signal from here is “Optimum_Voltage” which will be one of the inputs to the subsystem “Requirement_2 (DisplayUnit) ”.

b) Requirement_2

The Requirement_2 is also called as Display Unit. The simulink blocks inside the simulink model are created as per the given data in Requirement 2. I have used a Saturation Block for Signal “Enable_Display” for the signal saturation between the range 0 – 7. Output signal from the subsystem is “Output_Display”.

Creating a Simulink Data Dictionary (sldd file): -

After creating the simulink model go to Modeling then click on the down arrow of DESIGN and select Link to data dictionary.Now a new page will open then click on new, after that click on Apply & OK. So that, it will automatically have linked to our required Simulink model

In Order to add signals in Sldd file we have to add signals and calibration data in these Simulink signals for input signals

To add signals, we have to select Simulink signals in Add option also for input signals select storage class as 'Import External'.

For Output signal Select Storage Class as 'Export to file' in same output signal we have to give header file name and definition file name

For local signals select Storage class as 'localizable'. In order to add Calibration data, we have to select Simulink parameters in in same Add option

Basic modeling settings:-

selecting Solver Type as 'Fixed step'.

In Code generation we have to select System Target file as 'ert.tlc'.

Generated C code for the Simulink Model : -

/*
 * File: ert_main.c
 *
 * Code generated for Simulink model 'traffic_jam_assistance'.
 *
 * Model version                  : 1.13
 * Simulink Coder version         : 9.5 (R2021a) 14-Nov-2020
 * C/C++ source code generated on : Sat Jul  2 22:30:04 2022
 *
 * Target selection: ert.tlc
 * Embedded hardware selection: Intel->x86-64 (Windows64)
 * Code generation objectives: Unspecified
 * Validation result: Not run
 */

#include <stddef.h>
#include <stdio.h>              /* This ert_main.c example uses printf/fflush */
#include "traffic_jam_assistance.h"    /* Model's header file */
#include "rtwtypes.h"

/*
 * Associating rt_OneStep with a real-time clock or interrupt service routine
 * is what makes the generated code "real-time".  The function rt_OneStep is
 * always associated with the base rate of the model.  Subrates are managed
 * by the base rate from inside the generated code.  Enabling/disabling
 * interrupts and floating point context switches are target specific.  This
 * example code indicates where these should take place relative to executing
 * the generated code step function.  Overrun behavior should be tailored to
 * your application needs.  This example simply sets an error status in the
 * real-time model and returns from rt_OneStep.
 */
void rt_OneStep(void);
void rt_OneStep(void)
{
  static boolean_T OverrunFlag = false;

  /* Disable interrupts here */

  /* Check for overrun */
  if (OverrunFlag) {
    rtmSetErrorStatus(traffic_jam_assistance_M, "Overrun");
    return;
  }

  OverrunFlag = true;

  /* Save FPU context here (if necessary) */
  /* Re-enable timer or interrupt here */
  /* Set model inputs here */

  /* Step the model */
  traffic_jam_assistance_step();

  /* Get model outputs here */

  /* Indicate task complete */
  OverrunFlag = false;

  /* Disable interrupts here */
  /* Restore FPU context here (if necessary) */
  /* Enable interrupts here */
}

/*
 * The example "main" function illustrates what is required by your
 * application code to initialize, execute, and terminate the generated code.
 * Attaching rt_OneStep to a real-time clock is target specific.  This example
 * illustrates how you do this relative to initializing the model.
 */
int_T main(int_T argc, const char *argv[])
{
  /* Unused arguments */
  (void)(argc);
  (void)(argv);

  /* Initialize model */
  traffic_jam_assistance_initialize();

  /* Attach rt_OneStep to a timer or interrupt service routine with
   * period 0.2 seconds (the model's base sample time) here.  The
   * call syntax for rt_OneStep is
   *
   *  rt_OneStep();
   */
  printf("Warning: The simulation will run forever. "
         "Generated ERT main won't simulate model step behavior. "
         "To change this behavior select the 'MAT-file logging' option.\n");
  fflush((NULL));
  while (rtmGetErrorStatus(traffic_jam_assistance_M) == (NULL)) {
    /*  Perform other application tasks here */
  }

  /* Disable rt_OneStep() here */

  /* Terminate model */
  traffic_jam_assistance_terminate();
  return 0;
}

/*
 * File trailer for generated code.
 *
 * [EOF]
 */

Generating Model Advisor Report: -

go to modeling and select model Advisor. Now a page will open, Here go Task and select Modeling Standards for MAB & JMAAB.Then filnally select 'Run Selected Checks'.

MA report

we can reduce the warning by changing the certain parameters in MA report. here I have reduced the warning from 16 to 13.

Conclusion: -

⦁ Fully developed a Simulink model of single feature of traffic Jam Assistance as per the MAAB guidelines.

⦁ Created Simulink Data Dictionary file with detailed description.

⦁ Generated a C Code using the Embedded Coder as well as MA Report.