Traction Control - Revision history

SpookySimon: /* Rationale */ not passing vibe check

2024-03-21T18:48:43Z

Rationale: not passing vibe check

Satiric: Add to drivetrain category, remove from other categories, minor formatting

2023-02-03T04:20:00Z

Add to drivetrain category, remove from other categories, minor formatting

SpookySimon at 13:14, 30 March 2022

2022-03-30T13:14:47Z

SpookySimon: adding words to launch control/mid corner

2022-03-29T18:30:30Z

adding words to launch control/mid corner

SpookySimon: image of tc algo

2022-03-29T18:05:51Z

image of tc algo

SpookySimon: fixing weird image thing again

2022-03-29T17:54:40Z

fixing weird image thing again

SpookySimon: fixing weird image repetition

2022-03-29T17:53:10Z

fixing weird image repetition

Satiric: /* EV Motor Control */

2022-03-07T04:21:59Z

EV Motor Control

Yessamgerg at 00:54, 6 March 2022

2022-03-06T00:54:02Z

Yessamgerg: WIP vel est, slip est, slip target, failure modes summaries

2022-03-06T00:50:02Z

WIP vel est, slip est, slip target, failure modes summaries

@@ Line 8: / Line 8: @@
 <youtube>https://youtu.be/1-zUmZH7WDA</youtube>
-This should not be confused with lateral traction which is controlled by the dark wizards in the fourth dimension who demand virginal sacrifices. Depending on the driver's skill, how much lateral load is carried by the tires, the surface conditions, the setup of the chassis etc. the targeted slip will differ.
+This should not be confused with lateral traction which is controlled by the dark wizards in the fourth dimension who demand sacrifices. Depending on the driver's skill, how much lateral load is carried by the tires, the surface conditions, the setup of the chassis etc. the targeted slip will differ.
 ==Basic Principles<br />==

@@ Line 1: / Line 1: @@
 [[Engine Control]]
 ==Rationale==
 [[File:Tire slip and grip.PNG|none|middle|thumb|Grip Coefficient vs Slip]]
 Tire generates most longitudinal grip (good stuff) when slightly slipping (see pic). Need complex system of electronics and mind tricks to enable this condition at all possible times. This will enable go fast more. A demonstration of slip ratio is shown in the video below.
 <youtube>https://youtu.be/1-zUmZH7WDA</youtube>
 This should not be confused with lateral traction which is controlled by the dark wizards in the fourth dimension who demand virginal sacrifices. Depending on the driver's skill, how much lateral load is carried by the tires, the surface conditions, the setup of the chassis etc. the targeted slip will differ.
 ==Basic Principles<br />==
@@ Line 20: / Line 14: @@
 ===Velocity Estimate===
 In a rear wheel drive vehicle, a reasonable first pass would be to take the average of the two front wheels speeds. Because these wheels are un-driven, they are generally going to be traveling the same speed as the ground. Further considerations need to be taken for an AWD vehicle sense the lack of un-driven wheels means that wheel speeds alone can't be used to determine how fast the vehicle is going. In these cases a variety of solutions such as integrating the longitudinal acceleration can be used to fill in periods where the wheels are slipping.
 The same AWD considerations apply in the case of an RWD EV with regen since while braking the front wheels will be in slip.
 ===Slip Estimation===
 Once the vehicle velocity is determined, it is possible to determine the amount of slip that the tire is experiencing.
 It is important to also consider the effects of the different corner radii that the inside vs outside and front vs rear wheels travel while the vehicle is turning.
@@ Line 49: / Line 41: @@
 [[File:Traction_control_cornering_diagram.png|none|middle|thumb|Mid Corner Forces Modulated by Traction Control]]
 =References=
-[[Category:Electric Vehicle]]
+[[Category:Drivetrain]]

@@ Line 7: / Line 7: @@
-Tire generates most longitudinal grip (good stuff) when slightly slipping (see pic). Need complex system of electronics and mind tricks to enable this condition at all possible times. This will enable go fast more.
+Tire generates most longitudinal grip (good stuff) when slightly slipping (see pic). Need complex system of electronics and mind tricks to enable this condition at all possible times. This will enable go fast more. A demonstration of slip ratio is shown in the video below.
@@ Line 29: / Line 31: @@
 In a basic system, the slip target can be set to the slip at which the tire produces it's peak torque. If the velocity estimate is robust and the traction control regulation is well tuned, this will provide good acceleration performance in a straight line while aiding stability in a corner. Further improvements can be made by modifying the slip targets when the vehicle is turning, since with increasing slip angle the slip ratio for peak longitudinal force tends to reduce.
 ===Combustion Engine Control===
-The spin of the wheels is managed by speeding them up or slowing them down. This can either be done by the engine, clutch, or brakes. Dont do brakes because thats insane [citation needed]. Clutch modulation is often present/inherent in motorcycle clutches, but do not trasnlate well to this application.
+The spin of the wheels is managed by speeding them up or slowing them down. This can either be done by the engine, clutch, or brakes. FSAE rules don't allow electronic brake actuation. Clutch modulation is often present/inherent in motorcycle clutches, but do not translate well to this application. The most consistent and quickest mode of control is spark retard <ref> Fedullo, T. and Delagrammatikas, G., "The Traction Control System of the 2011 Cooper Union FSAE Vehicle," SAE Technical Paper 2011-01-1108, 2011, https://doi.org/10.4271/2011-01-1108.</ref>.
 ===EV Motor Control===
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 ==Mid Corner Traction Control==
 Since the cars are largely RWD, traction control can lower the rear wheel torque in a corner when an oversteer condition is detected, ensuring the driver remains in control at all times. This is often done by gyroscopic measurements taken on the front and rear ends of the vehicle. BETTER EXPLAINED IN PICS METHINKS
+[[File:Traction_control_cornering_diagram.png|none|middle|thumb|Mid Corner Forces Modulated by Traction Control]]
+=References=
 [[Category:Electric Vehicle]]
 [[Category:Internal Combustion]]

@@ Line 47: / Line 47: @@
 Since traction control is able to reduce (or completely eliminate) motor torque, it is important to consider the failure modes of the system. This can be as simple as providing the driver a switch to disable traction control, or more complex where either through electrical or model based checks of the plausibility of sensor values. In either case its possible that the driver may not realize that a loss of torque is caused by traction control, so some feedback mechanism to tell the driver when traction control is active is worth considering.
 ==Launch Control==
-launch control stops burnouts which is more faster but less cool
+Lunch control or other longitudinal acceleration applications for traction control hold the wheel slip ratio close to optimum for straight line acceleration without going over.<br />[[File:Traction control algo example.png|none|middle|thumb|Example of Traction Control Algorithm]]
-[[File:Traction control algo example.png|none|middle|thumb|Example of Traction Control Algorithm]]
+==Mid Corner Traction Control==
 [[Category:Electric Vehicle]]

@@ Line 48: / Line 48: @@
 ==Launch Control==
 launch control stops burnouts which is more faster but less cool
-* algo
+[[File:Traction control algo example.png|none|middle|thumb|Example of Traction Control Algorithm]]
 ==Mid Corner Traction Control==

← Older revision		Revision as of 17:54, 29 March 2022
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	[[Engine Control]]		[[Engine Control]]
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−	<a class="image"><img alt="" src="/images/d/da/Tire_slip_and_grip.PNG" decoding="async" width="300" height="273" class="thumbimage"></a> <a class="internal" title="Enlarge"></a>Grip Coefficient vs Slip
	Tire generates most longitudinal grip (good stuff) when slightly slipping (see pic). Need complex system of electronics and mind tricks to enable this condition at all possible times. This will enable go fast more.		Tire generates most longitudinal grip (good stuff) when slightly slipping (see pic). Need complex system of electronics and mind tricks to enable this condition at all possible times. This will enable go fast more.

@@ Line 1: / Line 1: @@
 [[Engine Control]]
@@ Line 8: / Line 12: @@
-<a class="image"><img alt="" src="/images/d/da/Tire_slip_and_grip.PNG" decoding="async" class="thumbimage" width="300" height="273"></a>  <a class="internal" title="Enlarge"></a>Grip Coefficient vs Slip
+<a class="image"><img alt="" src="/images/d/da/Tire_slip_and_grip.PNG" decoding="async" width="300" height="273" class="thumbimage"></a>  <a class="internal" title="Enlarge"></a>Grip Coefficient vs Slip
 Tire generates most longitudinal grip (good stuff) when slightly slipping (see pic). Need complex system of electronics and mind tricks to enable this condition at all possible times. This will enable go fast more.
 This should not be confused with lateral traction which is controlled by the dark wizards in the fourth dimension who demand virginal sacrifices. Depending on the driver's skill, how much lateral load is carried by the tires, the surface conditions, the setup of the chassis etc. the targeted slip will differ.
@@ Line 55: / Line 50: @@
 In lieu of a computed traction control based on degrees of slip, there are simpler solutions. Different throttle maps can be used, to make the car more driveable. This might be nice for events like skidpad, where fine control of the throttle is more important than raw power. A simple RC filter could be inserted into the circuit, so that a fast on-throttle event results in a gradual increase to max throttle. A PID controller could also accomplish this. These solutions would need to be bypassed on off-throttle events, as the traction control algorithm cannot increase the requested torque (at least in FSAE).
 ==Failure Modes==
 Since traction control is able to reduce (or completely eliminate) motor torque, it is important to consider the failure modes of the system. This can be as simple as providing the driver a switch to disable traction control, or more complex where either through electrical or model based checks of the plausibility of sensor values. In either case its possible that the driver may not realize that a loss of torque is caused by traction control, so some feedback mechanism to tell the driver when traction control is active is worth considering.
@@ Line 66: / Line 60: @@
 * algo
 [[Category:Electric Vehicle]]