Project 1- Traffic Jam Assistant Feature

Traffic Jam Assistant :

Problem Statement:

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. The Project must be done keeping in mind the following processes & steps.

• 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.

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”.

ANSWER :

AIM :

To develop a Simulink model to develop one specific requirement of Traffic Jam Assistant algorithm which would predominantly feature in the IPC algorithm as per MBD guidelines.

Objective of Main Project :

The Project must be done keeping in mind the following processes & steps.

• 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.

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”.

THEORY :

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 km / h, the driver can activate the functionality with the press of a button. The vehicle will now automatically follow the vehicle in front, takes over driving off, accelerating, 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. 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.
• The 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 Assist is pretty much an extension of Traffic Jam Assistant. Traffic Jam Assist works when you approach to traffic and slow to a crawl. With the system on, you can take your foot off the pedals. Traffic Jam Assist brakes and accelerates the car for you while maintaining a safe distance from the vehicle in front. This is essentially a low-speed version of Adaptive Cruise Control.
• Adaptive Cruise Control tries to maintain your set speed but takes other vehicles into account. Let's say you set your cruising speed to 90km/h, but the vehicle in front of your car is only doing 80km/h due to traffic. Adaptive Cruise Control will maintain a safe distance from the vehicle in front. Your car will not travel at 90km/h.
• Traffic Jam Assist works when the driver has his or her hands on the wheel. Most systems are designed to disengage if the driver's hands leave the wheel for too long. This is done to help ensure that the driver can take over in case of an emergency. Like Adaptive Cruise Control, Traffic Jam Assist systems err on the side of caution and leave big gaps to the vehicle in front. In places like Singapore, expect cars to filter into your lane. Impatient drivers behind you may even honk and/or flash their headlights. Traffic Jam Assist isn't very reactive either.
• An attentive driver who is situationally aware will be able to start accelerating the car faster, too. Also, when we are stationary for too long, the system won't move the car when traffic starts to move. We need to tap the accelerator pedal to 'activate' Traffic Jam Assist.

Simulation :

There are some steps to be followed to develop the model of Traffic Jam Assistant feature. They are mainly as follows;

Step-1 - Develop the Simulink data library for the model from the given data :

Under modelling, Link to data dictionary enables us to create a new SLDD for our model. Otherwise, in the modelling tab select the model properties option, where a pop up appears. Then, select new and give the name of the SLDD. After providing its name deselect the enable model access to base workspace option and click apply and OK and open the SLDD file.

The SLDD is designed based on the data given below:

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

The following Simulink data dictionary is created based on the data of the input, local, calibration and output signals given above in the design data option.

Step-2 - Change the model settings to MBD compliance changes :

There are some steps to be followed to develop the model of Traffic Jam Assistant feature. First, changed the model settings to MBD compliance changes. MBD compliance settings includes solver type to be changed to Fixed-step discrete (no continuous states) and fixed step size to 0.01s. Under the code generation the target file is changed to Embedded Coder. For changing the settings to MBD compliance changes, first click on the modelling tab and go to model configuration parameters and do the following changes.

Step-3 - Develop the Simulink model :

Here, the Simulink model is created based on the given requirements along with the given data of the input, local, calibration and output signals, by taking into consideration of MBD guidelines. Based on the given requirements, separate subsystems are made for requirement 1 and requirement 2.

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”.

Here, the input signal “Input_Voltage” from the inport is given to the two relational operator blocks which compares this input signal “Input_Voltage” against the calibrated constant voltage values “VOLTAGE_MINIMUM_RANGE” & “VOLTAGE_MAXIMUM_RANGE”. The calibration constant “VOLTAGE_MAXIMUM_RANGE” is given as the first input to the first ">=" relational operator block, while the “Input_Voltage” signal is given as the second input to the same, which implements the logic “VOLTAGE_MAXIMUM_RANGE” is greater than or equal to “Input_Voltage”. Then, the input signal “Input_Voltage” is given as the first input to the next ">=" relational operator block, while the “VOLTAGE_MINIMUM_RANGE” calibration constant is given as the second input to the same, which implements the logic “Input_Voltage” is greater than or equal to “VOLTAGE_MINIMUM_RANGE”. The outputs from the two relational operator blocks are given to the logical operator block "AND". The output signal from the AND block is “Optimum_Voltage”, which is the output signal of the first subsystem is given to the outport.

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”.

Here, the first input signal from the inport “Enable_Display” is given to a saturation block which is saturated between the range 0 – 7 (ie, upper limit = 7 and lower limit = 0). The output from the saturation block is compared against pre – defined set of values in a multiport switch, where the total data ports in the multiport switch is 5. The calibration constant “ON_MODE” is given as the inputs to the ports 1 and 2 of the multi-port switch, the calibration constant “OFF_MODE” is given as the inputs to the ports 3 and 4 of the multi-port switch and the calibration constant “STANDBY_MODE” is given as the input to the port 5 of the multi-port switch. The output from the the multi-port switch is given as the first input to a switch block.

The second input signal "Optimum_Voltage:" which is the output signal from the first subsystem is given as the first input to the first AND block with the third input signal “Input_Switch” which is given to a "NOT" relational operator block and given as the second input to the first AND block and the output of this AND block is given as the first input of the second AND block. Also, two calibration constant blocks “INTERRUPT_1” and “INTERRUPT_2” are compared with a relational operator block. ie, the “INTERRUPT_1” is given as the first input to an "==" relational operator block with the “INTERRUPT_2” given as the second input to the same. It activates the logic “INTERRUPT_1”==“INTERRUPT_2”. The output from the == relational operator block is given as the second input to the second AND block and the output of the second AND block is given as the second input of the switch block.

The third input of the switch block is the calibration constant “NO_DISPLAY”. The output signal of the switch block is the “Output_Display”, which is the output signal of the second subsystem is given to an outport.

Determine resolved signals and propagate signals in the model :

Step-4 - Model Advisory Check for MAB standards :

In the modelling tab, first select the Model Advisor window. Under Model Advisor window, choose by task and select modeling standards for MAB and select run selected checks option on the right.

After the checks a report will be developed showing the pass, fail and warnings for the model. The report shown below indicates that 131 checks has been passed, 0 had failed failed and there are 13 warnings present in the model. So, the model is now ready, taking into considerations the MBD and MAAB guidelines. The model advisory report is given below;

Step-5 :

Then, code generation is performed by clicking on the Embedded C code option in the apps tab. After its selection, click on build code to generate the auto codes along with the code generation report.

Step-6 - Requirement tagging :

The subsystems are tagged to the respective requirements provided in a word file.

Requirement 1 subsystem is tagged to the heading requirement 1 using the link to selection in word option.

Similarly Requirement 2 subsystem is tagged to the heading requirement 2 using the link to selection in word option.

CONCLUSION :

A Simulink model for the Traffic Jam Assistant feature was developed with the given requirements and the model advisory check for the model was done and the results showed zero failed conditions and less than 15 warnings for MAB standards. The model advisory report and code generated as .c and .h files for the model are attached with this report.