4.27. Vehicle Speed Limit Controller - VehSpdLimCtl

• Overview

• Functions

• Ports

• Parameters

• Configuration Steps

Id	VehSpdLimCtl
Version	0.4.0.0
Title	Vehicle Speed Limit Controller
System	Drivetrain
Document Type	Application Software Component Specification Preview

4.27.1. Overview

The Vehicle Speed Limit Control component determines the desired vehicle speed limit based on inputs from various sources such as safety systems, driver settings, ADAS, etc. It arbitrates between the different speed limit requests and selects the minimum speed limit to be applied. The component also controls the vehicle torque to maintain the selected speed limit.

4.27.2. Functions

Title	Description
Speed Limit Source Selection	Selects the minimum speed limit from the various input sources - safety speed limit, HMI speed limit, ADAS speed limit, limp mode speed limit, reverse gear speed limit. Enables the selected speed limit if it is valid.
Speed Limit Torque Control	Controls the vehicle torque to maintain the selected speed limit. Calculates the desired acceleration/deceleration based on the difference between current vehicle speed and the selected speed limit. Limits the torque demand accordingly.

4.27.3. Ports

	Id	Direction	Data Type	Dimensions	Unit	Description	Keywords
1	Ts	Incoming	single	[1]	s	Expected signal: Vehicle longitudinal speed If signal si NA: mandatory.	Ts
2	VehSpd	Incoming	single	[1]	km/h	Expected signal: Vehicle longitudinal speed If signal si NA: mandatory.	Vehicle Speed
3	VehSpdVld	Incoming	boolean	[1]	inherit	Expected signal: Vehicle speed signal validity If signal si NA: mandatory. True	Vehicle Speed Valid
4	VehTqDmd	Incoming	single	[1]	N*m	Expected signal: Vehicle torque demand If signal si NA: mandatory.	Vehicle Torque Demand
5	AccPedlPosn	Incoming	single	[1]	%	Expected signal: Accelerator pedal position If signal si NA: mandatory.	Acc Pedal Position
6	SftySpdLim	Incoming	uint16	[1]	km/h	Expected signal: Safety speed limit If signal si NA: mandatory. Any reasonable low enough positive value	Safety Speed Limit
7	HmiSpdLim	Incoming	uint16	[1]	km/h	Expected signal: Safety speed limit if hmi is not operative If signal si NA: mandatory. Any reasonable low enough positive value	Hmi Speed Limit
8	AdSpdLim	Incoming	uint16	[1]	km/h	Expected signal: Safety speed limit as per Automated driving request If signal si NA: mandatory. Any reasonable low enough positive value	Ad Speed Limit
9	LimpModSpdLim	Incoming	uint16	[1]	km/h	Expected signal: Vehicle speed set by limp mode If signal si NA: mandatory.	Limp Mode Speed Limit
10	SftySpdLimVld	Incoming	boolean	[1]	inherit	Expected signal: Safety speed limit validity signal If signal si NA: true If request must be considered	Safety Speed Limit Valid
11	HmiSpdLimVld	Incoming	boolean	[1]	inherit	Expected signal: Safety speed limit if hmi is not operative If signal si NA: true If request must be considered	Hmi Speed Limit Valid
12	AdSpdLimVld	Incoming	boolean	[1]	inherit	Expected signal: Safety speed limit as per Automated driving request If signal si NA: true If request must be considered	Ad Speed Limit Valid
13	LimpModSpdVld	Incoming	boolean	[1]	inherit	Expected signal: Limp mode speed selected? If signal si NA: true If request must be considered	Limp Mode Speed Valid
14	RevGearSeld	Incoming	boolean	[1]	inherit	Expected signal: Reverse gear engaged? If signal si NA: true If reverse gear is engaged	Revolution Gear Selected
15	VsplimctlVehTqLim	Outgoing	single	[1]	N*m		Vsplimctl Vehicle Torque Limit
16	VsplimctlVehTqThr	Outgoing	single	[1]	N*m		Vsplimctl Vehicle Torque Throttle
17	VsplimctlSpdLimEngd	Outgoing	boolean	[1]	inherit		Vsplimctl Speed Limit Engaged
18	VsplimctlSpdLimIntglEngd	Outgoing	boolean	[1]	inherit		Vsplimctl Speed Limit Integral Engaged
19	VsplimctlSpdLimSeld	Outgoing	uint16	[1]	km/h		Vsplimctl Speed Limit Selected
20	VsplimctlSpdLimSrc	Outgoing	Enum: CmndrvSpdLimSrc	[1]	inherit		Vsplimctl Speed Limit Source
21	VsplimctlSpdLimEna	Outgoing	boolean	[5]	inherit		Vsplimctl Speed Limit Enable

4.27.4. Parameters

	Id	Data Type	Dimensions	Range	Unit	Description	Keywords
1	VsplimctlKickdwAccrPosn	single	[1,1]	Min: 0, Max: 100	%	Pedal position for kickdown activation	Vsplimctl Kickdown Accelerator Position
2	VsplimctlSpdLimRevVal	uint16	[1,1]	Min: 0, Max: 50	km/h	Vehicle Speed Limit for Reverse Gear	Vsplimctl Speed Limit Revolution Value
3	VsplimctlLowrThdSpdLim	uint8	[1,1]	Min: 0, Max: 255	km/h	Minimum Vehicle Speed Limit Threshold for input range monitoring	Vsplimctl Lower Threshold Speed Limit
4	VsplimctlAdSpdLimEna	boolean	[1,1]	Min: 0, Max: 1		Enable ADAS speed limit	Vsplimctl Ad Speed Limit Enable
5	VsplimctlHmiSpdLimEna	boolean	[1,1]	Min: 0, Max: 1		Enable HMI speed lim	Vsplimctl Hmi Speed Limit Enable
6	VsplimctlLimpSpdLimEna	boolean	[1,1]	Min: 0, Max: 1		Enable Limp Mode speed limit	Vsplimctl Limp Speed Limit Enable
7	VsplimctlRevGearSpdLimEna	boolean	[1,1]	Min: 0, Max: 1		Enable Reverse limit	Vsplimctl Revolution Gear Speed Limit Enable
8	VsplimctlSftySpdLimEna	boolean	[1,1]	Min: 0, Max: 1		Enable safety speed lim	Vsplimctl Safety Speed Limit Enable
9	VsplimctlSpdLimKickdwEna	boolean	[1,2]	Min: 0, Max: 1		Enable KickDown for HMI, ADAS	Vsplimctl Speed Limit Kickdown Enable
10	VsplimctlSpdLimValNotAvl	uint16	[1,1]	Min: 0, Max: 500	km/h	Vehicle Speed Limit NotAvailable value	Vsplimctl Speed Limit Value Not Available
11	VsplimctlTqCtlMaxDrvVehTq	single	[1,1]	Min: 0, Max: 10000	N*m	Maximum vehicle drive torque	Vsplimctl Torque Control Maximum Drive Vehicle Torque

4.27.5. Configuration Steps

The VehSpdLimCtl shall be configured according to the vehicle architecture and the desired speed limit hold performance.

4.27.5.1. Step 1 - Configure Speed Limit Sources

Enable/Disable the various speed limit sources that will provide the speed constraints for the vehicle.
These sources include HMI, ADAS, safety systems, limp mode, and reverse gear limits.

Enable or disable the following speed limit sources based on the specific system’s requirements:
HMI Speed Limit (VsplimctlHmiSpdLimEna)

• Description: Enable the HMI speed limit. This allows the system to apply a speed limit as defined by the Human-Machine Interface (HMI).
  ADAS Speed Limit (VsplimctlAdSpdLimEna)
  Description: Enable the ADAS (Advanced Driver Assistance Systems) speed limit.
  Safety Speed Limit (VsplimctlSftySpdLimEna)
  Description: Enable the safety speed limit, which ensures the vehicle doesn’t exceed a certain speed for safety purposes.
  Limp Mode Speed Limit (VsplimctlLlimpSpdLimEna)
  Description: Enable the limp mode speed limit, which activates when the system is in a degraded state.
  Reverse Gear Speed Limit (VsplimctlRevGearSpdLimEna)
  Description: Enable the speed limit when the vehicle is in reverse gear.
  

4.27.5.2. Step 2 - Configure Speed Control Function

Configure the desired speed hold performance and acceleration/deceleration limits.

Set the following parameters to adjust vehicle speed stabilization performance:
Desired Acceleration Limit (VsplimctlAccLimDes)
Specifies the desired acceleration limit (in m/s²). This defines how quickly the vehicle can increase its speed.

Desired Deceleration Limit (VsplimctlDeceLimDes)
Specifies the desired deceleration limit (in m/s²). This defines how quickly the vehicle can decrease its speed.

Speed Frequency Band Desired (VsplimctlSpdFrqBndDes)
Specifies the desired frequency band for the vehicle speed to ensure smooth control.

Speed Frequency Integral Band Desired (VsplimctlSpdFrqIntglBndDes)
Specifies the desired integral frequency band for vehicle speed control to account for cumulative variations.

4.27.5.3. Step 3 - Configure Speed Limit Kickdown Logic

Kickdown logic provides a temporary manual override of the speed limit when driver deems necessary.

Set the following parameters to define the conditions under which speed limit kickdown is triggered:

Kickdown Accelerator Position (VsplimctlKickdwAccrPosn)
Defines the accelerator position threshold that triggers the kickdown logic. If the accelerator position exceeds this threshold, the speed limit is temporarily overridden.

Enable Speed Limit Kickdown (VsplimctlSpdLimKickdwEna)
Enable or disable the kickdown logic. When enabled, the vehicle can temporarily exceed the speed limit based on the kickdown condition.

4.27.5.4. Step 4 - Configure Speed Limit Fault Monitors

Speed limit fault monitoring ensures that the system can detect unstable signal faults at the inputs from speed limit sources.

Set the following parameters to configure fault detection:
Speed Limit Value Not Available Flag (VsplimctlSpdLimValNotAvl)
Sets the flag indicating that the speed limit value is unavailable. This could occur due to sensor failure or invalid inputs.

Speed Limit Switch Time (VsplimctlSpdLimSwtTi)
Defines the time threshold for detecting a speed limit switch. This is used to detect if the speed limit has been changed within a specified time window.

Speed Limit Switch Filter Reset Time (VsplimctlSpdLimSwtFlRstTi)
Defines the reset time for the speed limit switch filter, which helps prevent frequent or unnecessary speed limit switches.