Project 2 Adaptive Cruise Control

AIM: To develop the vehicle Adaptive Cruise Control feature using MATLAB Simulink.

OBJECTIVE:

• Develop an Adaptive Cruise Control feature as per the Requirement Document available using MATLAB & Simulink.
• To Follow all the MBD related processes: Requirement Tagging & Traceability, SLDD creation, Configuration Parameter changes, Model Advisor check & Code Generation using Embedded Coder.

Software/Tool Used: MATLAB R2021a

GENERAL OVERVIEW:

Adaptive Cruise Control Feature for passenger cars allows the host vehicle to adapt to the speed in line with the flow of traffic. Driving in heavy traffic or keeping a safe distance to the preceding vehicle calls for a high level of concentration. The Adaptive Cruise Control feature can reduce the stress on the driver by automatically controlling the vehicle speed & maintaining a predefined minimum distance to the preceding vehicle. As a consequence, the driver enjoys more comfort & can concentrate on the road little better.

A radar sensor is usually at the core of the Adaptive Cruise Control. Installed at the front of the vehicle, the system permanently monitors the road ahead. As long as the road ahead is clear, cruise control feature maintains the speed set by the driver. If the system spots a slower vehicle within its detection range, it gently reduces speed by releasing the accelerator or actively engaging the brake control system. If the vehicle ahead speeds up or changes lanes, the cruise control automatically accelerates to the driver’s desired speed.

Standard Adaptive Cruise Control can be activated from speeds of around 30 km/h (20 mph) upwards and supports the driver, primarily on cross-country journeys or on freeways. The cruise control stop & go variant is also active at speeds below 30 km/h (20 mph). It can maintain the set distance to the preceding vehicle even at very low speeds and can decelerate to a complete standstill. When the vehicle remains stopped longer, the driver needs only to reactivate the system, for example by briefly stepping on the gas pedal to return to cruise control mode. In this way, cruise control stop & go supports the driver even in heavy traffic and traffic jams.

Since Adaptive Cruise Control is a comfort and convenience system, brake interventions and vehicle acceleration only take place within defined limits. Even with Adaptive Cruise Control switched on, it remains the driver’s responsibility to monitor the speed and distance from the vehicle in front.

ACC systems use onboard computers and sophisticated sensors, such as radar or laser systems, to monitor the other vehicles on the road. Because of this, adaptive cruise control is also called radar cruise control or autonomous cruise control.

Once the driver locks his or her preferred speed into the ACC system, the vehicle will monitor its surroundings. The system runs a signal from its radar headway system through a digital signal processor to determine the distance to the nearest car, and it then uses a longitudinal controller to determine a safe following distance.

If the driver’s vehicle has too little following distance, the ACC system sends a signal to the engine or brakes, slowing the vehicle down. Once the path is clear, the ACC system will accelerate the vehicle back to the driver’s preferred speed. By restricting airflow to the engine when the vehicle is close to its speed setting and increasing airflow when the vehicle is below its speed setting, the cruise control system helps the car maintain a near-constant speed.

Signals & Calibration Data List:

Simulink Model:    

Inside Adaptive_Cruise_Control subsystem:

PROCEDURE:

Requirement 1– Lead Vehicle:

• Lead Vehicle is a vehicle which is driving in the road ahead of our drive vehicle. Two input signals (Signal Name: CameraInput_LeadVehicle & RadarInput_LeadVehicle).
• Ideally sensor fusion techniques will be deployed to process & analyze data from camera & radar. For complexity reasons, let’s not adapt to any such algorithms.
• We can simply add both the radar & camera inputs & the corresponding output is read as Speed profile output (Signal Name: LeadVehicle_Speed).
• Speed data of the lead vehicle is critical in implementing the Adaptive Cruise Control algorithm.

Requirement 2 – Drive Vehicle:

• Drive Vehicle is the vehicle driven by the user & this is the vehicle which has ACC algorithm in it.
• Like the Lead Vehicle, Drive Vehicle algorithm also has 2 input signals (Signal Name: CameraInput_DriveVehicle, RadarInput_DriveVehicle) & one signal coming as an Input to this subsystem (Signal Name: Acceleration_Mode) – three inputs into this requirement in total.
• Like the above requirement, sensor fusion techniques will also be deployed here, for complexity reasons we are ignoring them.
• Two output signals come from this subsystem (Signal Name: DriveVehicle_Speed & LeadVehicle_Detected).
• Signal DriveVehicle_Speed is summation of three input signals mentioned above & LeadVehicle_Detected is renamed from Input Signal RadarInput_DriveVehicle by mere use of Signal Conversion block.

Requirement 3 – Adaptive Cruise Control Algorithm:

• Adaptive Cruise Control feature has 3 major modes of operation: OFF Mode, STANDBY Mode & ON Mode. This particular requirement has to be implemented as state machine logic in Simulink.
• The input signals to this state machine system are (Signal Name: Time_Gap, Set_Speed, Set_Gap, CruiseSwitch, SetSwitch).
• Also, the output signals (Signal Name: DriveVehicle_Speed & LeadVehicle_Detected) from requirement-2 is fed back as an input signal into this state machine block.
• Additionally, output signal (Signal Name: LeadVehicle_Speed) from requirement-1 is given as an input signal to this state machine block as well.
• Output from this subsystem is a signal (Signal Name: Acceleration_Mode) which governs the vehicular speed of the drive vehicle which automatically adjusts its speed & velocity to match the lead vehicle.

Requirement 3a – ACC OFF MODE state logic:

• This is the default state inside state machine logic. Output signal Acceleration_Mode is at value 0 in this state.
• This state is governed by input signal CruiseSwitch.
• If CruiseSwitch is equal to 1, state ACC STANDBY mode will get activated. If CruiseSwitch is equal to 0, state ACC OFF mode will get activated, from either ACC ON mode or ACC STANDBY mode

Requirement 3b – ACC STANDBY MODE state logic:

• This is the second activated state inside state machine logic. Output signal Acceleration_Mode is at value 1 in this state.
• This state is governed by both input signals CruiseSwitch & SetSwitch.
• If CruiseSwitch is equal to 1, state ACC STANDBY mode will get activated. If CruiseSwitch is equal to 0, state ACC OFF mode will get activated, from either ACC ON mode or ACC STANDBY mode
• If SetSwitch is equal to 1, state ACC ON mode will get activated. If SetSwitch is equal to 0, state ACC STANDBY mode will get activated.

Requirement 3c – ACC ON MODE state logic:

This state will be activated when input signal SetSwitch is equal to 1. There are 6 sub states to this state logic: They are:

• LeadVehicle_Detected_Follow (Default)
• LeadVehicle_Not_Detected
• LeadVehicle_Detected_Resume
• LeadVehicle_Not_Detected_Resume
• LeadVehicle_Speed_lessthan_Set_Speed
• LeadVehicle_Speed_equal_Set_Speed

Requirement 3c (i) – LeadVehicle_Detected_Follow (ACC ON MODE):

• This is the default sub state inside ACC ON MODE state. Output signal Acceleration_Mode is equal to 2.
• Condition to transit from LeadVehicle_Detected_Follow to LeadVehicle_Not_Detected; Input signal condition LeadVehicle_Detected == 0.
• Condition to transit from LeadVehicle_Detected_Follow to LeadVehicle_Speed_lessthan_Set_Speed; Input Signals condition (LeadVehicle_Detected == 1) && (LeadVehicle_Speed < Set_Speed) || (Time_Gap < Set_Gap).

Requirement 3c (ii) – LeadVehicle_Not_Detected (ACC ON MODE):

• Output signal Acceleration_Mode is equal to 1.
• Condition to transit from LeadVehicle_Not_Detected to LeadVehicle_Detected_Follow; Input signals condition [(LeadVehicle_Detected==1) && (DriveVehicle_Speed == Set_Speed) && (LeadVehicle_Speed >= Set_Speed) && (Time_Gap >= Set_Gap)]
• Condition to transit from LeadVehicle_Not_Detected to LeadVehicle_Speed_lessthan_Set_Speed; Input signals condition [(LeadVehicle_Detected == 1) && (LeadVehicle_Speed < Set_Speed) || (Time_Gap < Set_Gap)]

Requirement 3c (iii) – LeadVehicle_Detected_Resume (ACC ON MODE):

• Output signal Acceleration_Mode is equal to 3.
• Condition to transit from LeadVehicle_Detected_Resume to LeadVehicle_Detected_Follow; Input signals condition [(DriveVehicle_Speed == Set_Speed) && (LeadVehicle_Speed >= Set_Speed) && (Time_Gap >= Set_Gap)]
• Condition to transit from LeadVehicle_Detected_Resume to LeadVehicle_Not_Detected_Resume; Input signal condition LeadVehicle_Detected==0.
• Condition to transit from LeadVehicle_Detected_Resume to LeadVehicle_Speed_equal_Set_Speed; Input Signal condition [(DriveVehicle_Speed < Set_Speed) && (LeadVehicle_Speed > DriveVehicle_Speed) && (Time_Gap >= Set_Gap)]

Requirement 3c (iv) - LeadVehicle_Not_Detected_Resume (ACC ON MODE):

• Output signal Acceleration_Mode is equal to 1.

Requirement 3c (v) - LeadVehicle_Speed_lessthan_Set_Speed (ACC ON MODE):

• Output signal Acceleration_Mode is equal to 4.
• Condition to transit from LeadVehicle_Speed_lessthan_Set_Speed to LeadVehicle_Not_Detected; Input signal condition [(LeadVehicle_Detected == 0) && (DriveVehicle_Speed == Set_Speed)]
• Condition to transit from LeadVehicle_Speed_lessthan_Set_Speed to LeadVehicle_Speed_equal_Set_Speed; Input signals condition [((LeadVehicle_Speed*1.25>=DriveVehicle_Speed) && (LeadVehicle_Speed * 0.75<=DriveVehicle_Speed)) && (DriveVehicle_Speed < Set_Speed) && ((Time_Gap<=1.25*Set_Gap) && (Time_Gap >=0.75*Set_Gap))]

Requirement 3c (vi) - LeadVehicle_Speed_equal_Set_Speed (ACC ON MODE):

• Output signal Acceleration_Mode is equal to 5.
• Condition to transit from LeadVehicle_Speed_equal_Set_Speed to LeadVehicle_Not_Detected_Resume; Input signal conditions is [(LeadVehicle_Detected == 0) || (DriveVehicle_Speed <= Set_Speed)]
• Condition to transit from LeadVehicle_Speed_equal_Set_Speed to LeadVehicle_Detected_Resume; Input signal conditions [(DriveVehicle_Speed < Set_Speed) && (LeadVehicle_Speed > DriveVehicle_Speed) || (Time_Gap >= Set_Gap)]
• Condition to transit from LeadVehicle_Speed_equal_Set_Speed to LeadVehicle_Speed_lessthan_Set_Speed; Input signals conditions [(LeadVehicle_Speed<Set_Speed) && (LeadVehicle_Speed<DriveVehicle_Speed) || (Time_Gap==0.75*Set_Gap)] 

Simulink Data Dictionary:

After creating the model, each signal, calibration parameters & variables are configured and stored in the Simulink Data Dictionary by the name ACC_SLDD.sldd

Configuration Parameter Changes:

Under code generation setting of configuration parameters, Embedded coder is used for code generation using code language as 'c' where system target file is selected as ert.tlc 

Model Advisor Check & Model Report:

Model advisor checks are performed to ensure the warnings & errors present in the model & model setting should get minimized. And these errors & warnings are rectified/optimized accordingly on each Model Advisor run.

Model advisor checks are performed on Modeling Standards for MISRA C:2012 and eliminated all errors & warnings. After doing this model advisor report is obtained. 

Model Advisor Report:

Code Generation:

After getting zero errors & warnings in model advisor report we proceed for code generation by selecting Apps>>Embedded Coder>>Build>>Generate Code and Build Model or else we can simply do Ctrl D (for updating model) and Ctrl B option for code generation.

Generated code files are attached for reference.

/*
 * Trial License - for use to evaluate programs for possible purchase as
 * an end-user only.
 *
 * File: Adaptive_Cruise_Control.c
 *
 * Code generated for Simulink model 'Adaptive_Cruise_Control'.
 *
 * Model version                  : 1.34
 * Simulink Coder version         : 9.5 (R2021a) 14-Nov-2020
 * C/C++ source code generated on : Tue Dec  7 19:44:34 2021
 *
 * Target selection: ert.tlc
 * Embedded hardware selection: Intel->x86-64 (Windows64)
 * Code generation objectives: Unspecified
 * Validation result: Not run
 */

#include "Adaptive_Cruise_Control.h"
#include "Adaptive_Cruise_Control_private.h"
#include "rt_roundd_snf.h"

/* Named constants for Chart: '<S4>/Adaptive Cruise Control Algorithm' */
#define Ada_IN_LeadVehicle_Not_Detected ((uint8_T)4U)
#define Adaptive_Cr_IN_ACC_STANDBY_MODE ((uint8_T)3U)
#define Adaptive_Cru_IN_NO_ACTIVE_CHILD ((uint8_T)0U)
#define Adaptive_Cruise_IN_ACC_OFF_MODE ((uint8_T)1U)
#define Adaptive_Cruise__IN_ACC_ON_MODE ((uint8_T)2U)
#define IN_LeadVehicle_Detected_Follow ((uint8_T)1U)
#define IN_LeadVehicle_Detected_Not_Res ((uint8_T)2U)
#define IN_LeadVehicle_Detected_Resume ((uint8_T)3U)
#define IN_LeadVehicle_Speed_equal_Set_ ((uint8_T)5U)
#define IN_LeadVehicle_Speed_lessthan_S ((uint8_T)6U)

/* Exported data definition */

/* Definition for custom storage class: ExportToFile */
uint8_T Acceleration_Mode;        /* '<S4>/Adaptive Cruise Control Algorithm' */

/* Definition for custom storage class: Localizable */
uint8_T DriveVehicle_Speed;            /* '<S3>/Add' */
uint8_T LeadVehicle_Detected;          /* '<S3>/Signal Conversion' */
uint8_T LeadVehicle_Speed;             /* '<S2>/Add' */

/* Block states (default storage) */
DW_Adaptive_Cruise_Control_T Adaptive_Cruise_Control_DW;

/* Real-time model */
static RT_MODEL_Adaptive_Cruise_Cont_T Adaptive_Cruise_Control_M_;
RT_MODEL_Adaptive_Cruise_Cont_T *const Adaptive_Cruise_Control_M =
  &Adaptive_Cruise_Control_M_;

/* Model step function */
void Adaptive_Cruise_Control_step(void)
{
  int32_T tmp;
  int32_T tmp_0;
  uint8_T tmp_1;
  uint8_T tmp_2;

  /* Outputs for Atomic SubSystem: '<Root>/Adaptive_Cruise_Control' */
  /* Sum: '<S3>/Add' incorporates:
   *  Delay: '<S1>/Delay'
   *  Inport: '<Root>/CameraInput_DriveVehicle'
   *  Inport: '<Root>/RadarInput_DriveVehicle'
   */
  DriveVehicle_Speed = (uint8_T)(((uint32_T)((uint8_T)(((uint32_T)
    RadarInput_DriveVehicle) + ((uint32_T)CameraInput_DriveVehicle)))) +
    ((uint32_T)Adaptive_Cruise_Control_DW.Delay_DSTATE[0]));

  /* Sum: '<S2>/Add' incorporates:
   *  Inport: '<Root>/CameraInput_LeadVehicle'
   *  Inport: '<Root>/RadarInput_LeadVehicle'
   */
  LeadVehicle_Speed = (uint8_T)(((uint32_T)CameraInput_LeadVehicle) + ((uint32_T)
    RadarInput_LeadVehicle));

  /* SignalConversion: '<S3>/Signal Conversion' incorporates:
   *  Inport: '<Root>/RadarInput_DriveVehicle'
   */
  LeadVehicle_Detected = RadarInput_DriveVehicle;

  /* Chart: '<S4>/Adaptive Cruise Control Algorithm' incorporates:
   *  Inport: '<Root>/CruiseSwitch'
   *  Inport: '<Root>/SetSwitch'
   *  Inport: '<Root>/Set_Gap'
   *  Inport: '<Root>/Set_Speed'
   *  Inport: '<Root>/Time_Gap'
   */
  if (((uint32_T)Adaptive_Cruise_Control_DW.is_active_c3_Adaptive_Cruise_Co) ==
      0U) {
    Adaptive_Cruise_Control_DW.is_active_c3_Adaptive_Cruise_Co = 1U;
    Adaptive_Cruise_Control_DW.is_c3_Adaptive_Cruise_Control =
      Adaptive_Cruise_IN_ACC_OFF_MODE;
    Acceleration_Mode = 0U;
  } else {
    switch (Adaptive_Cruise_Control_DW.is_c3_Adaptive_Cruise_Control) {
     case Adaptive_Cruise_IN_ACC_OFF_MODE:
      Acceleration_Mode = 0U;
      if (CruiseSwitch) {
        Adaptive_Cruise_Control_DW.is_c3_Adaptive_Cruise_Control =
          Adaptive_Cr_IN_ACC_STANDBY_MODE;
        Acceleration_Mode = 1U;
      }
      break;

     case Adaptive_Cruise__IN_ACC_ON_MODE:
      if (!SetSwitch) {
        Adaptive_Cruise_Control_DW.is_ACC_ON_MODE =
          Adaptive_Cru_IN_NO_ACTIVE_CHILD;
        Adaptive_Cruise_Control_DW.is_c3_Adaptive_Cruise_Control =
          Adaptive_Cr_IN_ACC_STANDBY_MODE;
        Acceleration_Mode = 1U;
      } else {
        switch (Adaptive_Cruise_Control_DW.is_ACC_ON_MODE) {
         case IN_LeadVehicle_Detected_Follow:
          Acceleration_Mode = 2U;
          if (((int32_T)LeadVehicle_Detected) == 0) {
            Adaptive_Cruise_Control_DW.is_ACC_ON_MODE =
              Ada_IN_LeadVehicle_Not_Detected;
            Acceleration_Mode = 1U;
          } else if (((((int32_T)LeadVehicle_Detected) == 1) &&
                      (LeadVehicle_Speed < Set_Speed)) || (Time_Gap < Set_Gap))
          {
            Adaptive_Cruise_Control_DW.is_ACC_ON_MODE =
              IN_LeadVehicle_Speed_lessthan_S;
          } else {
            /* no actions */
          }
          break;

         case IN_LeadVehicle_Detected_Not_Res:
          Acceleration_Mode = 1U;
          break;

         case IN_LeadVehicle_Detected_Resume:
          Acceleration_Mode = 3U;
          if (((DriveVehicle_Speed == Set_Speed) && (LeadVehicle_Speed >=
                Set_Speed)) && (Time_Gap >= Set_Gap)) {
            Adaptive_Cruise_Control_DW.is_ACC_ON_MODE =
              IN_LeadVehicle_Detected_Follow;
            Acceleration_Mode = 2U;
          } else if (((int32_T)LeadVehicle_Detected) == 0) {
            Adaptive_Cruise_Control_DW.is_ACC_ON_MODE =
              IN_LeadVehicle_Detected_Not_Res;
            Acceleration_Mode = 1U;
          } else if (((DriveVehicle_Speed < Set_Speed) && (LeadVehicle_Speed >
                       DriveVehicle_Speed)) && (Time_Gap >= Set_Gap)) {
            Adaptive_Cruise_Control_DW.is_ACC_ON_MODE =
              IN_LeadVehicle_Speed_equal_Set_;
          } else {
            /* no actions */
          }
          break;

         case Ada_IN_LeadVehicle_Not_Detected:
          Acceleration_Mode = 1U;
          if (((((int32_T)LeadVehicle_Detected) == 1) && (LeadVehicle_Speed <
                Set_Speed)) || (Time_Gap < Set_Gap)) {
            Adaptive_Cruise_Control_DW.is_ACC_ON_MODE =
              IN_LeadVehicle_Speed_lessthan_S;
          } else if ((((((int32_T)LeadVehicle_Detected) == 1) &&
                       (DriveVehicle_Speed == Set_Speed)) && (LeadVehicle_Speed >=
            Set_Speed)) && (Time_Gap >= Set_Gap)) {
            Adaptive_Cruise_Control_DW.is_ACC_ON_MODE =
              IN_LeadVehicle_Detected_Follow;
            Acceleration_Mode = 2U;
          } else {
            /* no actions */
          }
          break;

         case IN_LeadVehicle_Speed_equal_Set_:
          if ((((int32_T)LeadVehicle_Detected) == 0) || (DriveVehicle_Speed <=
               Set_Speed)) {
            Adaptive_Cruise_Control_DW.is_ACC_ON_MODE =
              IN_LeadVehicle_Detected_Not_Res;
            Acceleration_Mode = 1U;
          } else if (((DriveVehicle_Speed < Set_Speed) && (LeadVehicle_Speed >
                       DriveVehicle_Speed)) || (Time_Gap >= Set_Gap)) {
            Adaptive_Cruise_Control_DW.is_ACC_ON_MODE =
              IN_LeadVehicle_Detected_Resume;
            Acceleration_Mode = 3U;
          } else if (((LeadVehicle_Speed < Set_Speed) && (LeadVehicle_Speed <
                       DriveVehicle_Speed)) || (((int32_T)rt_roundd_snf(0.75 *
                        ((real_T)Set_Gap))) == ((int32_T)Time_Gap))) {
            Adaptive_Cruise_Control_DW.is_ACC_ON_MODE =
              IN_LeadVehicle_Speed_lessthan_S;
          } else {
            /* no actions */
          }
          break;

         default:
          /* case IN_LeadVehicle_Speed_lessthan_Set_Speed: */
          if ((((int32_T)LeadVehicle_Detected) == 0) && (DriveVehicle_Speed ==
               Set_Speed)) {
            Adaptive_Cruise_Control_DW.is_ACC_ON_MODE =
              Ada_IN_LeadVehicle_Not_Detected;
            Acceleration_Mode = 1U;
          } else {
            tmp = (int32_T)rt_roundd_snf(((real_T)LeadVehicle_Speed) * 1.25);
            tmp_0 = (int32_T)rt_roundd_snf(1.25 * ((real_T)Set_Gap));
            if (tmp < 256) {
              tmp_1 = (uint8_T)tmp;
            } else {
              tmp_1 = MAX_uint8_T;
            }

            if (tmp_0 < 256) {
              tmp_2 = (uint8_T)tmp_0;
            } else {
              tmp_2 = MAX_uint8_T;
            }

            if (((((tmp_1 >= DriveVehicle_Speed) && (((int32_T)rt_roundd_snf
                     (((real_T)LeadVehicle_Speed) * 0.75)) <= ((int32_T)
                     DriveVehicle_Speed))) && (DriveVehicle_Speed < Set_Speed)) &&
                 (Time_Gap <= tmp_2)) && (((int32_T)Time_Gap) >= ((int32_T)
                  rt_roundd_snf(0.75 * ((real_T)Set_Gap))))) {
              Adaptive_Cruise_Control_DW.is_ACC_ON_MODE =
                IN_LeadVehicle_Speed_equal_Set_;
            }
          }
          break;
        }
      }
      break;

     default:
      /* case IN_ACC_STANDBY_MODE: */
      Acceleration_Mode = 1U;
      if (!CruiseSwitch) {
        Adaptive_Cruise_Control_DW.is_c3_Adaptive_Cruise_Control =
          Adaptive_Cruise_IN_ACC_OFF_MODE;
        Acceleration_Mode = 0U;
      } else if (SetSwitch) {
        Adaptive_Cruise_Control_DW.is_c3_Adaptive_Cruise_Control =
          Adaptive_Cruise__IN_ACC_ON_MODE;
        Adaptive_Cruise_Control_DW.is_ACC_ON_MODE =
          IN_LeadVehicle_Detected_Follow;
        Acceleration_Mode = 2U;
      } else {
        /* no actions */
      }
      break;
    }
  }

  /* End of Chart: '<S4>/Adaptive Cruise Control Algorithm' */

  /* Update for Delay: '<S1>/Delay' */
  Adaptive_Cruise_Control_DW.Delay_DSTATE[0] =
    Adaptive_Cruise_Control_DW.Delay_DSTATE[1];
  Adaptive_Cruise_Control_DW.Delay_DSTATE[1] = Acceleration_Mode;

  /* End of Outputs for SubSystem: '<Root>/Adaptive_Cruise_Control' */
}

/* Model initialize function */
void Adaptive_Cruise_Control_initialize(void)
{
  /* (no initialization code required) */
}

/* Model terminate function */
void Adaptive_Cruise_Control_terminate(void)
{
  /* (no terminate code required) */
}

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