4.22. Torque Vectoring Control - TqVectCtl

• Overview

• Functions

• Ports

• Parameters

• Calibration

Id	TqVectCtl
Version	0.3.0.0
Title	Torque Vectoring Control
System	Drivetrain
Document Type	Application Software Component Specification Preview

4.22.1. Overview

The Torque Vectoring Controlller controls the distribution of driving torque between the left and right wheels to generate a yaw moment that improves vehicle handling and stability. It calculates a reference yaw moment based on driver inputs and vehicle states.

4.22.2. Functions

	Title	Description
1	Reference Yaw Moment Calculation	Calculates the reference yaw moment based on driver steering input, vehicle speed, and understeer/oversteer conditions. Uses feedforward and feedback control.
2	Torque Reduction	Reduces the total driving torque demand when TVC intervention is required to allow torque shifting between left and right wheels.
3	Torque Distribution	Determines the torque distribution ratio between left and right wheels to generate the desired yaw moment.
4	Activation Management	Determines if TVC should be active based on enable conditions, vehicle states, and driver mode selection.
5	Diagnostics and Fault Management	Monitors TVC inputs and outputs for out-of-range or invalid values. Sets diagnostic trouble codes and takes fault actions as needed.

4.22.3. Ports

	Id	Direction	Data Type	Dimensions	Unit	Description	Keywords
1	Ts	Incoming	single	[1]	s		Ts
2	RoadWhlAgDmd	Incoming	single	[1]	deg	Expected signal: Road wheel steering angle If signal is NA: Mandatory signal	Road Wheel Angle Demand
3	VehDrvTqDmd	Incoming	single	[1]	N*m	Expected signal: Total vehicle drive torque demand If signal is NA: Mandatory signal	Vehicle Drive Torque Demand
4	YawMomMaxAtTqDmd	Incoming	single	[1]	N*m	Expected signal: Maximum available yaw moment at the given drive torque demand If signal is NA: Mandatory signal	Yaw Moment Maximum At Torque Demand
5	YawMomMinAtTqDmd	Incoming	single	[1]	N*m	Expected signal: Minimum available yaw moment at the given drive torque demand If signal is NA: Mandatory signal	Yaw Moment Minimum At Torque Demand
6	VehYawRate	Incoming	single	[1]	deg/s	Expected signal: Vehicle yaw rate If signal is NA: Mandatory signal	Vehicle Yaw Rate
7	TyrSlipAgFrnt	Incoming	single	[1]	deg	Expected signal: Front tyre lateral slip angle If signal is NA: Mandatory signal	Tyre Slip Angle Front
8	TyrSlipAgRe	Incoming	single	[1]	deg	Expected signal: Rear tyre lateral slip angle If signal is NA: Mandatory signal	Tyre Slip Angle Rear
9	VehLgtSpd	Incoming	single	[1]	m/s	Expected signal: Vehicle longitudinal speed If signal is NA: Mandatory signal	Vehicle Longitudinal Speed
10	VehLatA	Incoming	single	[1]	m/s/s	Expected signal: Vehicle lateral acceleration If signal is NA: Mandatory signal	Vehicle Lateral Acceleration
11	VehStStsTvc	Incoming	boolean	[1]		Expected signal: Combined status flag for all signals required for Torque Vectoring If signal is NA: Mandatory. True	Vehicle State Status Tvc
12	TvcCtlStsReqd	Incoming	Enum: CmndrvHmiBtnReq	[1]		Expected signal: Activation request for Torque Vectoring If signal is NA: Set to true to activate Torque Vectoring, or false to disable it	Tvc Control Status Requested
13	GearPosnDrv	Incoming	Enum: CmnenaGearSt	[1]		Expected signal: Gear position If signal is NA: Mandatory signal	Gear Position Drive
14	TvcHmiCtlSts	Outgoing	Enum: CmndrvHmiBtnSts	[1]			Tvc Hmi Control Status
15	TvcEnadFlg	Outgoing	boolean	[1]			Tvc Enabled Flag
16	TvcOut1	Outgoing	Bus: CAN_TvcOut1_t	[-1]	inherit		Tvc Output1
17	TvcOut2	Outgoing	Bus: CAN_TvcOut2_t	[-1]	inherit		Tvc Output2
18	TvcOut1_send	Outgoing	boolean	[1]	inherit
19	TvcOut2_send	Outgoing	boolean	[1]	inherit
20	TvcAcv	Outgoing	boolean	[1]	inherit		Tvc Active
21	TvcRefYawMom	Outgoing	single	[1]	N*m		Tvc Reference Yaw Moment
22	TvcVehDrvgTqDmd	Outgoing	single	[1]	N*m		Tvc Vehicle Driving Torque Demand

4.22.4. Parameters

	Id	Data Type	Dimensions	Range	Unit	Description	Keywords
1	TvcCorrnFacSlipAgDifLut	single	[1,3]	Min: -90, Max: 90	deg	Slip angle activation vector for combined front/rear slip based correction factor LUT	Tvc Correction Factor Slip Angle Difference Lut
2	TvcCorrnFacSlipAgFilFrq	single	[1,1]	Min: 0, Max: 100	Hz	Cutoff frequency for low pass filter for CorrnFacSlipAg signal	Tvc Correction Factor Slip Angle Filter Frequency
3	TvcCorrnFacSlipAgLutDry	single	[1,3]	Min: 0, Max: 90	deg	Slip angle vector for LUT of correction factor in dry conditions	Tvc Correction Factor Slip Angle Lut Dry
4	TvcCorrnFacSlipAgLutSeln	int8	[1,1]	Min: 0, Max: 10	1	Selector type of slip angle based correction factor LUT: 1 - rear slip dry, 2 - rear slip wet, 3 - combined front and rear slip dry	Tvc Correction Factor Slip Angle Lut Selection
5	TvcCorrnFacSlipAgLutWet	single	[1,3]	Min: 0, Max: 90	deg	Slip angle vector for LUT of correction factor in wet conditions	Tvc Correction Factor Slip Angle Lut Wet
6	TvcAcvnLut	single	[1,5]	Min: , Max:		Tvc activation vector	Tvc Activation Lut
7	TvcAcvnLutVehLgtSpd	single	[1,5]	Min: , Max:		Speed activation vector	Tvc Activation Lut Vehicle Longitudinal Speed
8	TvcAcvnManOvrd	boolean	[1,1]	Min: , Max:		Manual override for Tvc Hmi activation request (true)	Tvc Activation Manual Override
9	TvcDrvTqDmdModAcvn	boolean	[1,1]	Min: , Max:		Enable Tvc torque reduction logic	Tvc Drive Torque Demand Mode Activation
10	TvcEnad	boolean	[1,1]	Min: , Max:		Enable Tvc	Tvc Enabled
11	TvcFfwCorrnFacLowrLim	single	[1,1]	Min: , Max:		Lower limit saturation of for correction factor for reference yaw moment feedforward	Tvc Feedforward Correction Factor Lower Limit
12	TvcFfwLutMod	single	[1,1]	Min: 1, Max: 10		Feedforward mode selection (1 - normal, 2 - eco, 3 - sport)	Tvc Feedforward Lut Mode
13	TvcRefYawMomFfwDbndSteer	single	[1,5]	Min: , Max:	deg	Road wheel angle dead band values for LUT based on speed	Tvc Reference Yaw Moment Feedforward Deadband Steering
14	TvcRefYawMomFfwDbndSteerLgtV	single	[1,5]	Min: , Max:	km/h	LUT speed breakpoints for road wheel angle dead band values	Tvc Reference Yaw Moment Feedforward Deadband Steering Longitudinal Velocity
15	TvcRefYawMomFfwFilFrq	single	[1,1]	Min: , Max:	Hz	Cut off frequency for low pass filter	Tvc Reference Yaw Moment Feedforward Filter Frequency
16	TvcRefYawMomFfwGainEco	single	[1,1]	Min: 0, Max: 10		Gain on feedforward TVC yaw moment for eco mode	Tvc Reference Yaw Moment Feedforward Gain Economy
17	TvcRefYawMomFfwGainNorm	single	[1,1]	Min: 0, Max: 10		Gain on feedforward TVC yaw moment for normal mode	Tvc Reference Yaw Moment Feedforward Gain Normal
18	TvcRefYawMomFfwGainSprt	single	[1,1]	Min: 0, Max: 10		Gain on feedforward TVC yaw moment for sport mode	Tvc Reference Yaw Moment Feedforward Gain Sprint
19	TvcSndTvcOut	boolean	[1,1]	Min: , Max:		Send Tvc CAN messages	Tvc Send Tvc Output
20	TvcTqRednFacOverSteer	single	[1,5]	Min: 0, Max: 1		Driving torque reduction factor in oversteer	Tvc Torque Reduction Factor Over Steering
21	TvcTqRednFacUndrSteer	single	[1,5]	Min: 0, Max: 1		Driving torque reduction factor in understeer	Tvc Torque Reduction Factor Under Steering
22	TvcTqRednFild	single	[1,1]	Min: 0, Max: 100		Torque reduction filter cutoff frequency	Tvc Torque Reduction Filtered
23	TvcTqRednYawMom	single	[1,5]	Min: 0, Max: 10000		Reference yaw moment breakpoints for LUTs	Tvc Torque Reduction Yaw Moment
24	TvcTqvTyrSlipAgFrntThd	single	[1,1]	Min: 0, Max: 90	deg	Front slip angle activation threshold for feedback component of TVC	Tvc Tqv Tyre Slip Angle Front Threshold
25	TvcTyrSlipAgReThd	single	[1,1]	Min: 0, Max: 90	deg	Rear slip angle activation threshold for feedback component of TVC	Tvc Tyre Slip Angle Rear Threshold
26	TvcYawMomOverSteerGainProp	single	[1,11]	Min: 0, Max: 10000		Proportional gain for PID controller of TVC yaw moment in oversteer	Tvc Yaw Moment Over Steering Gain Proportional
27	TvcYawMomUndrSteerGainProp	single	[1,11]	Min: 0, Max: 10000		Proportional gain for PID controller of TVC yaw moment in understeer	Tvc Yaw Moment Under Steering Gain Proportional
28	TvcYawRateErrOverSteerOffThd	single	[1,1]	Min: 0, Max: 100	deg/s	Deactivation threshold of equivalent lateral acceleration error for detection of oversteer	Tvc Yaw Rate Error Over Steering Off Threshold
29	TvcYawRateErrOverSteerOnThd	single	[1,1]	Min: 0, Max: 100	deg/s	Activation threshold of equivalent lateral acceleration error for detection of oversteer	Tvc Yaw Rate Error Over Steering On Threshold
30	TvcYawRateErrUndrSteerOffThd	single	[1,1]	Min: 0, Max: 100	deg/s	Deactivation threshold of equivalent lateral acceleration error for detection of understeer	Tvc Yaw Rate Error Under Steering Off Threshold
31	TvcYawRateErrUndrSteerOnThd	single	[1,1]	Min: 0, Max: 100	deg/s	Activation threshold of equivalent lateral acceleration error for detection of understeer	Tvc Yaw Rate Error Under Steering On Threshold
32	TvcLgtVVect	single	[1,11]	Min: 0, Max: 200		Vehicle speed breakpoints for LUTs	Tvc Longitudinal Velocity Vector
33	TvcFbAcv	boolean	[1,1]	Min: , Max:		Enable Yaw Moment feedback	Tvc Feedback Active
34	TvcFfwAcv	boolean	[1,1]	Min: , Max:		Enable Yaw Moment feedforward	Tvc Feedforward Active
35	TvcYawRateErrVehLgtVAcvn	single	[1,4]	Min: 0, Max: 100		Yaw Rate Error activation based on Vehicle speed	Tvc Yaw Rate Error Vehicle Longitudinal Velocity Activation
36	TvcYawRateErrVehLgtVVect	single	[1,4]	Min: 0, Max: 10000		Vehicle speed breakpoints for Yaw Rate Error activation	Tvc Yaw Rate Error Vehicle Longitudinal Velocity Vector
37	TvcRefYawMomFfwGainWithTqDmd	single	[1,1]	Min: , Max:		Gain on feedforward TVC yaw moment	Tvc Reference Yaw Moment Feedforward Gain With Torque Demand
38	TvcTqRednAcv	boolean	[1,1]	Min: , Max:		Vehicle speed breakpoints for Eco mode	Tvc Torque Reduction Active

4.22.5. Calibration

TqVectCtl software component must be set up and tuned in order to achieve the desired tracking performance of a feedback + feedforward controller providing the required vehicle performace. This calibration procedure assumes that the vehicle parameters have already been set according to the specific target vehicle.

4.22.5.1. Step 1 - Enable/Disable Torque Vectoring control

Set TvcEnad to true to enable Torque Vectoring control.

4.22.5.2. Step 1.1 - Provide Torque Vectoring activation tresholds based on vehicle longitudinal speed in km/h

TvcAcvnLut TVC activation vector
TvcAcvnLutVehLgtSpd Speed activation breakpoints

4.22.5.3. Step 2 - Set the reference yaw rate correction factor

In order to blend the reference handling and stability yaw rates, a correction factor is used. It is set based on the lateral slip angle of the tyres, and can be adjusted to allow for more or less TVC contribution depending on the tyre slip angles. Typically, higher slip angles can be allowed in dry conditions compared to wet conditions. Select the strategy to be applied via the TvcCorrnFacSlipAgLutSeln parameter:
1 Rear slip dry LUT. This case uses a vector of [1 1 0] as table data and the breakpoints specified in TvcCorrnFacSlipAgLutDry.
2 Rear slip wet LUT. This case uses a vector of [1 1 0] as table data and the breakpoints specified in TvcCorrnFacSlipAgLutWet.
3 Combined front and rear slip dry LUT. This case uses an array of [1 1 1;1 1 1;0 0 1] as table data and the breakpoints specified in TvcCorrnFacSlipAgLutDry and TvcCorrnFacSlipAgDifLut.
Dafault value is 3

4.22.5.4. Step 2.1 - Tuning of the breakpoints of the LUTs is possible via the following parameters:

TvcCorrnFacSlipAgLutDry Slip angle LUT breakpoints for correction factor in dry conditions. Vector size [1x3].
TvcCorrnFacSlipAgLutWet Slip angle LUT breakpoints for correction factor in wet conditions. Vector size [1x3].
TvcCorrnFacSlipAgDifLut Slip angle LUT breakpoints for correction factor in combined front/rear slip-based correction. Vector size [1x3].

4.22.5.5. Step 2.2 - Filtering of the correction factor

Because the correction factor is computed based on slips, it can vary quickly and potentially result in unnecessary variations of the yaw moment under highly dynamic conditions.Therefore, a low-pass filter can be tuned using TvcCorrnFacSlipAgFilFrq (in Hz) to smooth the value of the correction factor.

4.22.5.6. Step 3 - Reference Yaw Moment Feedforward contribution

Set TvcFfwAcv to true to enable the feedforward contribution

Tune, if necessary, the following parameters:
TvcRefYawMomFfwGainNorm
TvcRefYawMomFfwGainEco
TvcRefYawMomFfwGainSprt
to scale the FeedForward yaw moment maps for Normal Mode, Eco Mode and Sport Mode respectively. Default value is 1 for all of them.

4.22.5.7. Step 3.1 - Provide a dead-band interval for FeedForward contribution based on vehicle speed

A one-dimensional lookup table is used to set the dead-band intervall on the feedforward contribution of TVC. TvcRefYawMomFfwDbndSteer Road wheel angle dead-band values.
TvcRefYawMomFfwDbndSteerLgtV Vehicle speed breakpoints for road wheel angle dead-band values

4.22.5.8. Step 3.2 - Tune the FeedForward contribution low-pass filter

Tune, if necessary, the cut-off frequency (in Hz) of the low-pass filer on the feedforward yaw moment via TvcRefYawMomFfwFilFrq.

4.22.5.9. Step 4 - Reference Yaw Moment Feedback contribution

Set TvcFbAcv to true to activate the feedback contribution

4.22.5.10. Step 4.1 - Error activation for Feedback contribution

Tune, if necessary, the following parameters:
TvcYawRateErrUndrSteerOnThd Activation threshold of equivalent lateral acceleration error for the detection of understeer in deg/s
TvcYawRateErrUndrSteerOffThd Deactivation threshold of equivalent lateral acceleration error for the detection of understeer in deg/s
TvcYawRateErrOverSteerOnThd Activation threshold of equivalent lateral acceleration error for the detection of oversteer in deg/s
TvcYawRateErrOverSteerOffThd Deactivation threshold of equivalent lateral acceleration error for the detection of oversteer in deg/s

4.22.5.11. Step 4.2 - Provide tyre slip angle activation thresholds

Use TvcTqvTyrSlipAgFrntThd to set front slip angle activation threshold for feedback component of TVC (in deg)
Use TvcTyrSlipAgReThd to set rear slip angle activation threshold for feedback component of TVC (in deg)

4.22.5.12. Step 4.3 - Tune the Feedback controller

Adjust according to target performance the following parameters to modify the tracking performance of the feedback controller:

TvcYawMomOverSteerGainProp Proportional gain for PID controller of TVC yaw moment in oversteer, given as a vector corresponding to the longitudinal vehicle speed breakpoints below.
TvcYawMomUndrSteerGainProp Proportional gain for PID controller of TVC yaw moment in understeergiven as a vector corresponding to the longitudinal vehicle speed breakpoints below.
TvcLgtVVect vehicle speed breakpoints

Customise, if necessary, the cut-off frequency (in Hz) of the low-pass filter on the yaw moment output via TvcRefYawMomCtlAllcnFilFrq.

4.22.5.13. Step 4.4 - Tune the torque reduction factor

In case of dynamic driving under high total torque demand, the achievable yaw moment of TVC becomes significantly lowered due to the motor torques being close to the motor’s physical limits. Therefore, the corrective yaw moment cannot be applied by TVC to fully stabilise the vehicle. In such cases, a torque reduction factor can be activated by setting TvcTqRednAcv to true, which will reduce to total torque demand and allow for a higher yaw moment contribution instead. The reduction factor is defined as a lookup table using the following parameters for data and breakpoints:
TvcTqRednFacOverSteer Total driving torque reduction factor in oversteer
TvcTqRednFacUndrSteer Ttotal driving torque reduction factor in understeer
TvcTqRednYawMom Reference TVC feedback yaw moment breakpoints

4.22.5.14. Notes

Set TvcSndTvcOut to true to send TvcOut1 and TvcOut2 debug CAN messages