Project 1- Traffic Jam Assistant Feature

Introduction to Automotive Embedded Systems and AUTOSAR

PROJECT 1:  Traffic Jam Assistant Feature

Overview:

Traffic Jam Assistant is one of the most common features in the 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 the same lane.

Traffic jam assistance represents a significant investment in development and research. Prototypes were tested with consumers for more than a year and evolved to meet customer demand. The traffic jam assistance system seems to be framed like a safety device that has potential to reduce fender-bender type crashes in heavy driving -- Volvo, after all, is known for coming up with the latest and greatest automotive safety solutions. Volvo freely admits, though, that development of the traffic jam assistance system was motivated by customer demand -- in other words, it's as much of a luxury feature as it is a safety one. It just happens to be comprised of safety-based technology. But there's more  the name of the system, combined with its capabilities, seems to imply that it could perhaps reduce traffic jams by attacking the problem, rather than the symptoms.

Aim: To create a Simulink Data Dictionary, develop an algorithm for one of the features of Traffic Jam Assistance and generate a C code for it using Simulink.

Objective:

• Model Development as per MBD guidelines.
• Creation of Simulink Data Dictionary.
• Code Generation using Embedded Coder.
• Generating Model Advisor Report.

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 the press of a button. The vehicle will now automatically follow the vehicle in front, takes over driving off, acceleration, braking, and steering within the 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.

Signals & Calibration Data list:

Input Signals:

Output Signal:

Calibration Signals:

Local Signal:

Procedure:

The following figure shows the created Simulink Data Dictionary file according to the given input signals and calibration data.

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”.
• The 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. The output signal from the subsystem is “Output_Display”.
• Input Signal “Enable_Display” is compared against a pre-defined set of values in a multiport switch. The total data ports in the multiport switch are 5.
• Multiport switch inputs 1 & 2 are connected to calibration signal “ON_MODE”, Multiport switch inputs 3 & 4 are connected to calibration signal “OFF_MODE” while Multiport switch input 5 is connected to calibration signal “STANDBY_MODE”.
• The output from the 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 the value of the input signal “Input_Switch” is compared in an AND gate against the 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”.

The following figure shows the created Traffic Jam Assistance feature algorithm as per the requirement

The following figure shows the whole model created for the Traffic Jam Assistance feature with all input and output ports using Simulink

Model Advisor Report:

After running Modeling Standards for MAAB checks, we can see that there are 0 failures and hence, we can now proceed with the Code generation.

Code Generation:

.h file:

/*
 * File: traffic_jam_assistant.h
 *
 * Code generated for Simulink model 'traffic_jam_assistant'.
 *
 * Model version                  : 1.4
 * Simulink Coder version         : 9.5 (R2021a) 14-Nov-2020
 * C/C++ source code generated on : Tue Jul 27 13:31:49 2021
 *
 * Target selection: ert.tlc
 * Embedded hardware selection: Intel->x86-64 (Windows64)
 * Code generation objectives: Unspecified
 * Validation result: Not run
 */

#ifndef RTW_HEADER_traffic_jam_assistant_h_
#define RTW_HEADER_traffic_jam_assistant_h_
#ifndef traffic_jam_assistant_COMMON_INCLUDES_
#define traffic_jam_assistant_COMMON_INCLUDES_
#include "rtwtypes.h"
#endif                              /* traffic_jam_assistant_COMMON_INCLUDES_ */

#include "traffic_jam_assistant_types.h"

/* Macros for accessing real-time model data structure */
#ifndef rtmGetErrorStatus
#define rtmGetErrorStatus(rtm)         ((rtm)->errorStatus)
#endif

#ifndef rtmSetErrorStatus
#define rtmSetErrorStatus(rtm, val)    ((rtm)->errorStatus = (val))
#endif

/* Real-time Model Data Structure */
struct tag_RTM_traffic_jam_assistant_T {
  const char_T * volatile errorStatus;
};

/*
 * Exported Global Signals
 *
 * Note: Exported global signals are block signals with an exported global
 * storage class designation.  Code generation will declare the memory for
 * these signals and export their symbols.
 *
 */
extern uint8_T Output_Display;         /* '/Switch' */

/* Model entry point functions */
extern void traffic_jam_assistant_initialize(void);
extern void traffic_jam_assistant_step(void);
extern void traffic_jam_assistant_terminate(void);

/* Exported data declaration */

/* ConstVolatile memory section */
/* Declaration for custom storage class: ConstVolatile */
extern const volatile boolean_T Interrupt_1;/* Referenced by: '/Constant4' */
extern const volatile boolean_T Interrupt_2;/* Referenced by: '/Constant5' */
extern const volatile uint8_T No_Display;/* Referenced by: '/Constant3' */
extern const volatile uint8_T Off_Mode;/* Referenced by: '/Constant1' */
extern const volatile uint8_T On_Mode; /* Referenced by: '/Constant' */
extern const volatile uint8_T Standby_Mode;/* Referenced by: '/Constant2' */
extern const volatile uint8_T Voltage_Maximum_Range;/* Referenced by: '/Constant' */
extern const volatile uint8_T Voltage_Minimum_Range;/* Referenced by: '/Constant' */

/* Real-time Model object */
extern RT_MODEL_traffic_jam_assistan_T *const traffic_jam_assistant_M;

/*-
 * The generated code includes comments that allow you to trace directly
 * back to the appropriate location in the model.  The basic format
 * is /block_name, where system is the system number (uniquely
 * assigned by Simulink) and block_name is the name of the block.
 *
 * Use the MATLAB hilite_system command to trace the generated code back
 * to the model.  For example,
 *
 * hilite_system('')    - opens system 3
 * hilite_system('/Kp') - opens and selects block Kp which resides in S3
 *
 * Here is the system hierarchy for this model
 *
 * '' : 'traffic_jam_assistant'
 * ''   : 'traffic_jam_assistant/Traffic_Jam_Assistance_feature'
 * ''   : 'traffic_jam_assistant/Traffic_Jam_Assistance_feature/Requirement_1'
 * ''   : 'traffic_jam_assistant/Traffic_Jam_Assistance_feature/Requirement_2'
 * ''   : 'traffic_jam_assistant/Traffic_Jam_Assistance_feature/Requirement_1/Compare To Constant'
 * ''   : 'traffic_jam_assistant/Traffic_Jam_Assistance_feature/Requirement_1/Compare To Constant1'
 */
#endif                                 /* RTW_HEADER_traffic_jam_assistant_h_ */

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

.c file:

/*

 * File: traffic_jam_assistant.c

 *

 * Code generated for Simulink model 'traffic_jam_assistant'.

 *

 * Model version                  : 1.4

 * Simulink Coder version         : 9.5 (R2021a) 14-Nov-2020

 * C/C++ source code generated on : Tue Jul 27 13:31:49 2021

 *

 * Target selection: ert.tlc

 * Embedded hardware selection: Intel->x86-64 (Windows64)

 * Code generation objectives: Unspecified

 * Validation result: Not run

 */

 

#include "traffic_jam_assistant.h"

#include "traffic_jam_assistant_private.h"

 

/* Exported block signals */

uint8_T Output_Display;                /* '/Switch' */

 

/* Exported data definition */

 

/* ConstVolatile memory section */

/* Definition for custom storage class: ConstVolatile */

const volatile boolean_T Interrupt_1 = 1;/* Referenced by: '/Constant4' */

const volatile boolean_T Interrupt_2 = 1;/* Referenced by: '/Constant5' */

const volatile uint8_T No_Display = 0U;/* Referenced by: '/Constant3' */

const volatile uint8_T Off_Mode = 2U;  /* Referenced by: '/Constant1' */

const volatile uint8_T On_Mode = 1U;   /* Referenced by: '/Constant' */

const volatile uint8_T Standby_Mode = 3U;/* Referenced by: '/Constant2' */

const volatile uint8_T Voltage_Maximum_Range = 50U;/* Referenced by: '/Constant' */

const volatile uint8_T Voltage_Minimum_Range = 30U;/* Referenced by: '/Constant' */

 

/* Real-time model */

static RT_MODEL_traffic_jam_assistan_T traffic_jam_assistant_M_;

RT_MODEL_traffic_jam_assistan_T *const traffic_jam_assistant_M =

  &traffic_jam_assistant_M_;

 

/* Model step function */

void traffic_jam_assistant_step(void)

{

  /* local block i/o variables */

  boolean_T Optimum_Voltage;

  uint8_T tmp;

 

  /* Outputs for Atomic SubSystem: '/Traffic_Jam_Assistance_feature' */

  /* Logic: '/OR' incorporates:

   *  Constant: '/Constant'

   *  Constant: '/Constant'

   *  Inport: '/Input_Voltage'

   *  RelationalOperator: '/Compare'

   *  RelationalOperator: '/Compare'

   */

  Optimum_Voltage = ((Input_Voltage >= Voltage_Minimum_Range) || (Input_Voltage <=

    Voltage_Maximum_Range));

 

  /* Switch: '/Switch' incorporates:

   *  Constant: '/Constant4'

   *  Constant: '/Constant5'

   *  Inport: '/Input_Switch'

   *  Logic: '/NOT'

   *  Logic: '/NOT1'

   *  RelationalOperator: '/Relational Operator'

   */

  if (Optimum_Voltage && (!Input_Switch) && (Interrupt_1 == Interrupt_2)) {

    /* Saturate: '/Saturation' incorporates:

     *  Inport: '/Enable_Display'

     */

    if (Enable_Display < 7) {

      tmp = Enable_Display;

    } else {

      tmp = 7U;

    }

 

    /* End of Saturate: '/Saturation' */

 

    /* MultiPortSwitch: '/Multiport_Switch' */

    switch (tmp) {

     case 1:

      /* Switch: '/Switch' incorporates:

       *  Constant: '/Constant'

       */

      Output_Display = On_Mode;

      break;

 

     case 2:

      /* Switch: '/Switch' incorporates:

       *  Constant: '/Constant'

       */

      Output_Display = On_Mode;

      break;

 

     case 3:

      /* Switch: '/Switch' incorporates:

       *  Constant: '/Constant1'

       */

      Output_Display = Off_Mode;

      break;

 

     case 4:

      /* Switch: '/Switch' incorporates:

       *  Constant: '/Constant1'

       */

      Output_Display = Off_Mode;

      break;

 

     default:

      /* Switch: '/Switch' incorporates:

       *  Constant: '/Constant2'

       */

      Output_Display = Standby_Mode;

      break;

    }

 

    /* End of MultiPortSwitch: '/Multiport_Switch' */

  } else {

    /* Switch: '/Switch' incorporates:

     *  Constant: '/Constant3'

     */

    Output_Display = No_Display;

  }

 

  /* End of Switch: '/Switch' */

  /* End of Outputs for SubSystem: '/Traffic_Jam_Assistance_feature' */

}

 

/* Model initialize function */

void traffic_jam_assistant_initialize(void)

{

  /* (no initialization code required) */

}

 

/* Model terminate function */

void traffic_jam_assistant_terminate(void)

{

  /* (no terminate code required) */

}

 

/*

 * File trailer for generated code.

 *

 * [EOF]

 */

Software-In-Loop verification for the generated code using Simulation Data Inspector:

As we can see, the output display shows 3 and the tolerance is 0, we can conclude that the generated code has successfully passed the Software-In-Loop test.

Conclusion:

Thus, a Simulink Data Dictionary file has been created for the given signals and calibration data, an algorithm has been developed for one of the features of Traffic Jam Assistance, a Model Advisor report has been generated as per the MAAB guidelines, and a C code has been generated and verified for the required feature using Simulink. 

Google drive link of model and data dictionary files: https://drive.google.com/drive/folders/19cDTV-xUkKtkQv3jWmO6uF31R93nk6AV?usp=sharing