Project 2 Adaptive Cruise Control

1.

A.Aim:

The project has the following four aims:

I. Developing Adaptive Cruise Control feature as per the Requirement Document using MATLAB Simulink.

II.Follow all the MBD related processes: Requirement Tagging & Traceability, SLDD creation, Configuration Parameter changes, Model Advisor check & Code Generation.

III.In Configuration Parameters: enable “Support Floating Numbers” under Code Generation settings.

IV.Using Embedded Coder to generate the code.

B.Scope of Project:

• 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 with less effort and ease.
• 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 primary responsibility to monitor the speed and distance from the vehicle in front.

Modeling:

Step1(Change in Model setting):

A. Before going to do modelling we have to change model setting

B. For the model based development needs to change the configuration parameters as per our requirement. For changing the model configuration parameters we need to go to the Modeling section, select model setting and a new configuration parameters window gets opened.

C. In the Solver we change the solver type as Fixed-step, in Solver we choose discrete (no continuous states) and Fixed step size is 0.01. Then for code generation we require some changes in the code generation section.

D. For code generation settings wego to the Code Generation section select system target file as ert.tlc (Embedded Coder) by click on browse. Also as per mention in the question enable support floating numbers. For that goto the code generation > > Interface and select support floating point numbers.

Step 2(Creating SLDD file):

SLDD file is created from the list of Signals and Calibration given in this project.

For creating the SLDD file we go to the Modeling section and then to Design section.We select >> link to the data dictionary then one window popup, in that type the name >> disable the ‘Enable model access to base workspace’ and click on new then this SLDD file >> save in the same folder where simulink model is present.

SLDD file so created can be edited.For that purpose we need to click on the left bottom corner sign, open the SLDD file and make changes as per our requirement.

Step 3(Creating Model as per the given requirement):

Requirement 1– Lead Vehicle:

Lead Vehicle is a vehicle which is driving in the road ahead of our Drive Vehicle. Two input signals are fed to this (Signal Name: CameraInput_LeadVehicle & RadarInput_LeadVehicle).

Ideally sensor fusion techniques will be deployed to process & analyze data from camera & radar. For complexity reasons, let us not adapt to any such algorithm.

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 two 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 three 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.

As per this reqirement there are altogether eight inputs (namely Time_Gap, Set_Speed, Set_Gap, CruiseSwitch, SetSwitch, DriveVehicle_Speed & LeadVehicle_Detected) to the chart and one output (Acceleration_Mode).

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 six sub states to this state logic.These 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)]

Above is ACC_ON_MODE Requirement logic with 6 sub states (LeadVehicle_Detected_Follow (Default); LeadVehicle_Not_Detected; LeadVehicle_Detected_Resume; LeadVehicle_Not_Detected_Resume; LeadVehicle_Speed_lessthan_Set_Speed; LeadVehicle_Speed_equal_Set_Speed) as per Reqirement in Requirement 3c

Step 4): Defining input/output values in symbol plane & also update in Model Explorer >> chart.

Step5) : Signal Resolution And Propagation:

To resolve the signal we need to right click on signal line and then select 'Properties'.When this is done Signal Properties block will open.Next we write name or select name of signal and tick mark the appropriate box.All signals must be resolved in the Simulink model object.

After resolving signal if this signal comes again in model then at that time we have to propagate that signal.For propogation the methodology is almost similar.But in that case no selection is required and another box is required to be ticked.

For Propagation, we can choose direct method by typing <> and press enter key the signal will automatically propagate OR repeated above signal resolution process but dont enter signal name and check on >> show propagated signal >> OK.

Step 6): Requirement Tagging

For requirement tagging and traceability at beginning we want write all requirement in the word file, then select those position which we want to link to the respective any one subsystem, then goto the model subsystem >> right click on the subsystem and click on >> the requirement and select the >> link to selection in word. Now our subsyste is tagged to our requirement.

Step 7): Model Advisor Check

For model advisor test click on modeling select model advisor then select our model>> now new model advisor window will open >> select the Modelling Standard for MAB >> click on the run selected check then automatically testing will start after completing minimize the warning by changing recommended change and generate report.The report has been attached as report_352.This displays the following output.

Pass:129, Fail:0,Warning:11,Total:140

Step 8): Code Generation:

For code generation we have already changed the model configuration parameters, so now we need to go to the Apps section select >> Embedded Coder then >> new section open >> C Code in that click on >> build and select the >>Generate Code. Now automatically code will be generated and displayed on the right hand side of the model.

The generated code has been attached as ACCcode.

All other files related to this project are also enclosed and these are as under.

ACC.slx

Proj2Req1.slx

Proj2Req2.slx

Proj3Req3.slx

acc.sldd

Proj2Req1.docx

Proj2Req2.docx

Proj2Req3.docx