Active Rollover Protection (ARP) : What is it?

[SS-Traveller]

A new (in India) acronym called ARP made a sudden appearance in a recently-launched affordable car in the Indian market.

Originally Posted by blackwasp

The Ford Freestyle is on sale in India...

What you'll like:
• Titanium+ variant gets 6 airbags, ESP, ARP & HSA

This, to me, was an exciting little string of letters, which however did not stir many souls. In fact, multiple professional reviews of the Ford Freestyle across India only mentioned the acronym in passing, and no one thought to test out the system and assess its advantages.

So what is Active Roll-over Protection (ARP)?

ARP (the specific name) is a system patented to Ford Technologies LLC, with modifications and changes to the various systems over the last 20+ years. ARP is designed to reduce the risk of on-road rollover situations in case of dynamic (e.g. lane change) and steady state manoeuvres (e.g. vehicle turns with constant radius and increasing vehicle velocity).

Multiple other patents filed by various other manufacturers of automobiles and automotive control systems utilize similar principles to reduce chances of vehicle roll-over, except that the specific sensors and control modules are designed a little differently.

(ARP) is a systerm and a method for mitigating vehicle rollovers; the method comprises monitoring a vehicular tilt and sensing a vehicular rollover in a particular direction, through a tilt sensor. Further, the system determines an occurrence of a rollover according to a calculated tilt threshold, through a central processing unit. Steering the vehicle in the sensed direction of the rollover, accelerating the vehicle in the same direction, and braking the vehicle upon sensing a decrease in the rollover, all being controlled through a controller, enables the vehicle to eventually stabilize and return to track.

How do rollover mitigation systems work?

A couple of videos to explain the process of how rollover mitigation works:

The easiest video to understand the concept is by Mazda, whose Roll Stability Control (RSC) is similar to Ford's ARP.

https://www.youtube.com/watch?v=6WjfRxtIMzo

Volvo was perhaps the first car manufacturer to incorporate rollover mitigation systems in its SUVs, and it's called Roll-Over Protection System (ROPS). This utilizes the Roll Stability Control (RSC) function and has been designed to help minimize the risk of a rollover in emergency maneuvers or if a skid should occur.

The system uses a gyroscopic sensor that registers the amount of change in the lateral angle at which the vehicle is leaning. Using this information, the controller unit calculates the likelihood of a rollover. If there is an imminent risk of a rollover, the stability system is activated, power to the engine is cut and the brakes are applied to one or more of the wheels until the vehicle regains stability.

https://www.youtube.com/watch?v=Mmja6bC03Yw

Bosch, among a plethora of automotive control systems, also designs and manufactures components as well as software for rollover mitigation systems.

https://www.youtube.com/watch?v=K1Zfgl3CLsE

https://www.youtube.com/watch?v=VwLP1dXVcpM

In fact, Mahindra's latest XUV5OO sold in India now comes equipped with Bosch's Rollover Mitigation System - and that costs ~3x the price of the cheapest car in India with such a system (the Ford Freestyle).

Earlier models of the XUV5OO sold in India probably did not have the rollover mitigation system (owners please correct me if I am wrong), though the models exported to Australia (and probably South Africa) did (Australian Vehicle Standards Rules and Australian Design Rules make it mandatory for all new vehicles on sale since 2011 to be equipped with rollover mitigation function - including the now-discontinued Suzuki A-Star, called the Alto there, and the Celerio that is being currently sold in Australia).

Here's a Bosch video about the XUV5OO with ESP and TCS, but no mention of rollover mitigation.

https://www.youtube.com/watch?v=1IT2oMIBMz4

What is different between ESP & ARP?

Both ESP and ARP (or other acronyms carrying out similar functions), as well as TCS (traction control system), ABS (anti-lock braking system), EBD (electronic brake-force distribution), BA (brake assistant) and HHC (hill hold control) / HSA (hill start assist) / HDC (hill descent control) are part of the active safety functions of a vehicle, using automatic brake-system operations through electronic control, using a variety of sensors to detect
• wheel speed at all the wheels
• brake pedal and the force applied to it
• steering angle
• accelerator pedal
• tilt / dive, yaw, lateral acceleration & roll
• torque to each driven wheel

Based on the inputs received by the different sensors, an electronic control module and its software is capable of braking one or more individual wheels as well as reducing engine power as required, thus making the act of driving a car by an average driver (or even an expert driver) much safer and more controlled.

To sum up, the confidence and speed of Gaurav Gill while driving the top-end Freestyle up Kolli Hills may not be as high as portrayed in Ford's advertorial video, without the active safety features of the car, including ARP & ESP - which means that the lower versions of the same car would not perform as safely around corners as the one equipped with ARP + ESP does.

However, Ford has just proved that the latest vehicle safety technologies need not make a car frighteningly expensive to buy. It is time that all other manufacturers follow suit, and equip ALL their cars with active safety functions.

[GTO]

Thread moved from the Assembly Line to the Safety Section. Thanks for sharing!

[ariesonu]

Interestingly they have used 1st gen (CHEETAH) style XUV model in the videos.

I believe that car manufacturers should also do some R&D into preventing tyre burst cases, where the vehicle may sense sudden deflating of tyre(s) and take corrective action.

Rgds-Sonu

[Holyghost]

Originally Posted by SS-Traveller

However, Ford has just proved that the latest vehicle safety technologies need not make a car frighteningly expensive to buy. It is time that all other manufacturers follow suit, and equip ALL their cars with active safety functions.

Even though the technology advancement is great, the fact that a car is being loaded with more and more electronic sensors is a matter of concern. Until now, the driving aids were passive in nature and the failure of its sensors did not intervene with the normal operation of the vehicle. for eg, a failed ABS sensor did not impact the braking and only reduced the braking efficiency. The user could still drive and stop the vehicle.

Now when it comes to Active Systems these are designed to interfere with the driver inputs. The vehicle will brake even if the driver do not intend to brake. The vehicle will increase or reduce engine power/speed irrespective of your throttle input and with even advanced systems, the vehicle will steer itself based on the inputs from the sensors. I do not know how the vehicle will behave when these sensors malfunctions. Till now, I have replaced ABS Speed Sensor, MAF Sensor and the Temperature Sensor of the Climate Control System. All these failure did cause some minor inconvenience. The failure/malfunction of critical sensors of the active safety system will definitely inconvenience you and a badly designed software logic could even put you in danger.

I just hope introduction of these systems to cheaper vehicles does not mean the system itself is of cheaper and inferior quality.

[Flyer]

Watch this crash test video where Tesla attempts to roll over a Model X (and fails).

https://m.facebook.com/story.php?sto...73678916107053

The video shows some awesome results. The test platform here is sand and I am not sure if the results will be same on tarmac.

[SS-Traveller]

Originally Posted by ariesonu

I believe that car manufacturers should also do some R&D into preventing tyre burst cases, where the vehicle may sense sudden deflating of tyre(s) and take corrective action.

Tyre Pressure Monitoring Systems do detect and warn of bursts as well as potential burst situations (high / low pressure, rising temperature). ESP and ARP are capable of reducing the effect of a sudden blowout by reacting in a fraction of a second, much faster than a human can. The final outcome of how the electronics handle the stability depends, of course, on the software program that developers write for the controller. For example, look at this link:

While the Jeep never rolled, it was very unstable and managed to blowout the tire on the left front six times.
....
In my estimate, the problem here is the ESC and roll-over mitigation system software. The roll-over mitigation would decrease the hydraulic pressure to the wheel that has the most weight loaded on it. In the case of the Jeep, it would be the right front and then the left front during the maneuver. The braking force is then transfered to the other wheels.

But, it appears the calibration for the Jeep is a little off. The good news is that this can be corrected with software and not mechanical parts.

So, a tyre burst (especially during an extreme test) did not roll the vehicle over (even though the test itself was the cause of the burst).
-------------

Originally Posted by Holyghost

...the fact that a car is being loaded with more and more electronic sensors is a matter of concern. Until now, the driving aids were passive in nature and the failure of its sensors did not intervene with the normal operation of the vehicle. for eg, a failed ABS sensor did not impact the braking and only reduced the braking efficiency. The user could still drive and stop the vehicle.

Now when it comes to Active Systems these are designed to interfere with the driver inputs. The vehicle will brake even if the driver do not intend to brake. The vehicle will increase or reduce engine power/speed irrespective of your throttle input and with even advanced systems, the vehicle will steer itself based on the inputs from the sensors. I do not know how the vehicle will behave when these sensors malfunctions.

I believe this is called logizomechanophobia or technophobia. The whole purpose and focus of Active Safety is to prevent a crash from occurring, by controlling the vehicle in a better and more effective manner for a very short period of time, reacting faster than any average human driver can. Once the driver regains control, Active Safety systems do not interfere with his driving.

When you say: a failed ABS sensor did not impact the braking and only reduced the braking efficiency, it does not make sense - if braking efficiency is reduced, how can it not impact the braking?

Originally Posted by Holyghost

Till now, I have replaced ABS Speed Sensor, MAF Sensor and the Temperature Sensor of the Climate Control System. All these failure did cause some minor inconvenience. The failure/malfunction of critical sensors of the active safety system will definitely inconvenience you and a badly designed software logic could even put you in danger.

I just hope introduction of these systems to cheaper vehicles does not mean the system itself is of cheaper and inferior quality.

So the focus of your anti-Active-Safety stance is India-specific, where 'cutting corners in terms of quality' and 'cheap Chinese replacements' are taken to be the norm, while this thread simply attempts to explain in simple terms what benefits a rollover mitigation system offers to the average low-skilled driver. Your experience with failure of multiple sensors in your vehicle is sad and unfortunate, but I believe that is not the norm, even in the multitude of electronics-laden vehicles sold in India.

[MihirB]

Originally Posted by Flyer

Watch this crash test video where Tesla attempts to roll over a Model X (and fails).

The centre of gravity in a Tesla must've super low due to the battery pack being at the bottom of the car. But this is still some crazy stuff.

[venkyhere]

well written article

However, with boatloads of acronyms flashed like trophies by the marketing teams, people think nothing will happen to the vehicle, no matter how rash or harsh it is driven. For example, one of my friends thinks he does not need to slow down when its rainy, because his polo has ABS and EBD. I fear whether knowledge about this ARP will encourage people to drive like morons around corners - every system has a limit, all that these systems are doing, is reduce probability - that does not mean laws of physics stop getting applied to these cars.
I wish such technical features (starting from ABS, all the way now to ARP) does not get advertised to the average car buyer who is not interested in technical specs. A bit like mp3 music format, for example - nobody needs to know their ears are being fooled even after throwing away more data than whats being retained. These systems should silently work without anybody's knowledge and if there is a diagnostic malfunction on any of these active safety systems, just flash a big orange light on the dashboard that says "unless this car is taken to service center and an issue corrected, an accident is very likely to happen" in full sentence. People should still drive the same car, like they did old ones without even ABS.

[Naveen_0181]

Originally Posted by Holyghost

I do not know how the vehicle will behave when these sensors malfunctions.

I believe all the automobile functions will have a fail safe design! for example even when the EPS unit/motor fails we still can be able to steer the car with a little more effort, similarly when the brake assist fails(engine lost power) the breaks will still work when pressed really hard.

I am sure all these active safety technologies are also designed taking into account of all possible worst case scenarios! all modern cars will do a complete system check every time the key is turned on to ensure all the critical senors are working as desired.

Even after all these precautions there will some inevitable situations where the technology may fail! Safe driving techniques with aid of safety systems will reduce the chance of occurrence of mishaps.

[ariesonu]

[quote=SS-Traveller;4408807]Tyre Pressure Monitoring Systems do detect and warn of bursts as well as potential burst situations (high / low pressure, rising temperature). ESP and ARP are capable of reducing the effect of a sudden blowout by reacting in a fraction of a second, much faster than a human can. The final outcome of how the electronics handle the stability depends, of course, on the software program that developers write for the controller.[/url]:

I agree with TPM systems but in most cases these are EXTERNAL systems that are fitted by car owners. Even if inbuilt, it would save more lives if the system can read or detect possible tyre dynamics & provide safe driving inputs to vehicle. But then as HOLYGHOST has mentioned, too many electronic sensors are becoming a bane in actual driving experience.

Back in mid-90's, I remember when ARPA (Automatic Radar Plotting Aid) was added to RADARs on ship; as young officers, we were very fascinated by it but our Captains use to keep reminding us that it is an AID-TO-NAVIGATION & that it should never substitute our watch-keeping. Now the ships are also loaded with so much gadgetry but I still keep reminding my officers to keep a fair watch.

Regards-Sonu

[Surprise]

Originally Posted by SS-Traveller

without the active safety features of the car, including ARP & ESP - which means that the lower versions of the same car would not perform as safely around corners as the one equipped with ARP + ESP does.

Thanks for this detailed thread.

Is there anyway that we get activation data's of ESP/ARP on real time to mobile devices synced via some hardware? That would be interesting to get to know how these advanced technologies has come to our rescue. Once I have to swerve quickly, to avoid a 2 wheeler, coming out from a bush straight onto the highway. SUV struggled a lot to get back to its position & I very much believe its the ESP that has saved from the accident. Also decided, any of the future purchases will not be without such ESP/ARP

Originally Posted by venkyhere

I fear whether knowledge about this ARP will encourage people to drive like morons around corners - every system has a limit, all that these systems are doing, is reduce probability - that does not mean laws of physics stop getting applied to these cars.
I wish such technical features (starting from ABS, all the way now to ARP) does not get advertised to the average car buyer who is not interested in technical specs

In one of the online reviews of a SUV, a reviewer was mentioning that no way that SUV could be rolled over - I understand it was to emphasis how the Company has built in that feature, but as you mentioned rightly, people should not take things for granted

[ghodlur]

The thread really got me interested, reason being recently I had done the Hazard analysis of road transport for our company cars and had deliberated the need of roll over protection to prevent any toppling. Wanted to use the ARP on the left hand side of the bow tie as a barrier but after much discussion had to drop it due to unavailability of any feasible & viable products available in the market which can independently provide the roll over protection.

After reading the thread about availability of Bosch unit in some SUV, was searching for the same on the Bosch website for further details but could not get any info. Any inputs regarding this would be very helpful. I am planning to enquire with Bosch if there is any such product available which can fit in our company cars to prevent the toppling scenario. The cars in question are Innovas.

[Holyghost]

Originally Posted by SS-Traveller

I believe this is called logizomechanophobia or technophobia.

That sounds really serious and something uncalled for. I think I should get myself diagnosed.
At the same time, please ensure you are qualified enough and have the proper diagnostics before painting someone with a random psychiatric disorder on a public forum. This would go a long way ensuring a mutual respect and a healthy discussion on this community.

Originally Posted by SS-Traveller

When you say: a failed ABS sensor did not impact the braking and only reduced the braking efficiency, it does not make sense - if braking efficiency is reduced, how can it not impact the braking?

Despite a malfunctioning ABS sensor, I could brake and stop the car. The issue was with the rear left wheel sensor which caused the ABS to kick in randomly when I brake at low speeds.
So did it impact the braking? Technically Yes, but practically the brakes were still functioning and I could stop the car but the efficiency was reduced and it might have taken longer to stop the car. Personally I did not feel the stopping distance to be longer since the issue was with the rear wheel.

Originally Posted by SS-Traveller

So the focus of your anti-Active-Safety stance is India-specific, where 'cutting corners in terms of quality' and 'cheap Chinese replacements' are taken to be the norm, while this thread simply attempts to explain in simple terms what benefits a rollover mitigation system offers to the average low-skilled driver.

Am I being branded anti-Active-Safety for writing one post about my concerns based on my experiences with failed sensors on my car?. Indeed we are living in strange times.

Originally Posted by Naveen_0181

I believe all the automobile functions will have a fail safe design! for example even when the EPS unit/motor fails we still can be able to steer the car with a little more effort, similarly when the brake assist fails(engine lost power) the breaks will still work when pressed really hard.

Those are passive systems. Those systems will not do anything on their own and acts only as a power assist when you brake or Steer. The active systems on the other hand are designed to perform actions without any user input and works with the inputs from the sensors. If the gyroscope provides a signal that the vehicle is about to topple, the car will brake itself. As I said earlier, with more and more active systems, the vehicle will brake, accelerate and steer itself relying completely on the sensors and at times even over riding the user input.
In Takata Airbag issue, no one thought about what the age will do to the system. The manufacturers should put in all their efforts to ensure the systems are fool proof and do not malfunction due to age, climate or other conditions. Even if everything above is completely taken care of, we even have to be more cautious about the Indian manufacturers who is known to reduce the Airbags size, and structural rigidity just for cost savings.

Originally Posted by Naveen_0181

I am sure all these active safety technologies are also designed taking into account of all possible worst case scenarios! all modern cars will do a complete system check every time the key is turned on to ensure all the critical sensors are working as desired..

There is a difference between a failed sensor and a malfunctioning sensor. A failed sensor can easily be diagnosed, but it is really difficult to design a fail safe system for a malfunctioning sensor.
In my Cruze, the wheel speed sensor was malfunctioning, so the Check ABS light never came on. At the same time, the ABS was kicking in randomly when I come to a stop.

[supertinu]

Originally Posted by SS-Traveller

Earlier models of the XUV5OO sold in India probably did not have the rollover mitigation system (owners please correct me if I am wrong), though the models exported to Australia (and probably South Africa) did (Australian Vehicle Standards Rules and Australian Design Rules make it mandatory for all new vehicles on sale since 2011 to be equipped with rollover mitigation function - including the now-discontinued Suzuki A-Star, called the Alto there, and the Celerio that is being currently sold in Australia).

I believe the 1st generation of XUV500 did have this feature. Its referred to as ROM (roll over mitigation) in the user manual.

[roby_dk]

Roll Stability Control
The system enhances your vehicle’s ability
to prevent rollovers by detecting your
vehicle’s roll motion and the rate at which
it changes by applying the brakes to one
or more wheels individually.

This was mentioned in my user manual of Ford 3.2 Titanium. Hope this is present in Indian model and this feature is not skipped by Ford India. Is this a type of ARP?