Transformation of driver assistance systems – communication in future commercial vehicles
Assistance systems and its influence in today’s trucks
Truck driver decades ago had the full responsibility for their vehicle. Every traffic situation had to be controlled by the driver. Technical parameters had to be monitored and issues solved today’s driver would sometimes not anymore know how. Nobody really talked about driver assistance systems in a commercial vehicle.
This changed end of the 1970’s when first electronic devices were developed. The first driver assistance system in commercial trucks was WABCO’s ABS introduced for DB LKW in 1980. At that time such system was an exotic feature. But many more followed. Today many of these assistant systems are so common we do not really recognizing them. Most drivers would not expect a vehicle without ABS anymore. There are many other well-known systems like ECAS or ACC but also still very special systems like city assist, … Nobody would even talk about navigation systems anymore.
And the number of systems will increase furthermore walking the path to automated or au-tonomous driving. The idea of automated driving comes with the replacement of human capabilities. This requires many more and even more sufficient and integrated assistance systems and sensors. The exchange, selection and presentation of information will in-crease and being more important. With the number of assistance systems the role of to-day’s driver changes from former "manual" driver to the supervisor of all the systems con-trolling traffic, vehicle and … even the driver himself.
The role of driver
In today’s modern trucks the driver has still the most important role. He is supposed to ob-serve traffic and environment and controls the vehicle accordingly. The driver uses control systems; controls vehicle functions and is responsible for passengers and load.
To perform his tasks efficiently and safe every driver in modern vehicles is supported by many little helpers. Most of these systems require the attention, control and interaction of the driver for efficient usage. It moves the driver into the role of a coordinator integrating the efficient usage of different helpers. He becomes the communicator providing correct input to allow the usage and to interpret the information the helpers provide. The driver has become the role of the communication centre between all these systems which are sup-posed to support him and the vehicle usage.
Are these systems really supporting?
The increasing information flow on several displays with different interfaces and control concepts requires attention distracting the driver from his major task, from driving a vehicle safe and efficiently during challenging traffic situations. The historical role of a truck driver is changing and will require increasing capabilities, knowledge how to use the helpers and the information they create. Many of these helpers require interaction and training. Some-times concepts to operate the helpers demonstrates the technical capabilities and interests of development engineers but are not focussed on driver demands. Most of today’s sup-porting helper systems are not well integrated or provide comprehensive connection be-tween each other. On the other hand drivers face periods of with very few tasks and chal-lenges where the helpers control the driving and partial traffic conditions.
Do we really trust our helpers?
Many assistance systems are made to support the driver especially during critical or an-noying traffic, driving or system conditions. This could e.g. be an instable driving condition during curves or simply braking on slippery surfaces. It could also be a special system condition e.g. monitoring tire pressure or the proper function of the cooling system. But it could also be a situation where the route goes just straight for miles and miles. It can be a great support reducing overstressing situations but it also leads to situations with very low task load causing distraction of the driver. Even though most helpers are not allowed to operate fully autonomous according to legal requirements the driver has always to be able to take control of the vehicle and its systems.
The situation raises questions about the influence of common helpers. Does the situation lead to overstraining or under challenge of the driver? How to keep the driver at an opti-mum level of attraction performing his changed role as system supervisor and communica-tor?
Supporting the driver
Looking at the field of commercial vehicles it usually comes with one aspect which touches the passenger car world just peripherally, the interaction between truck and trailer. The purpose of trucking is carrying goods safe and efficient. Trucks are first hand investments to perform business. Cost of ownership is one of the KPIs. There is not much room for gimmick. The appropriate operation of the whole vehicle is mature for the fleet.
One basic task for the driver is the interaction and communication between truck and trailer systems. In the role of interpreter, controller and driver he has to combine truck and trailer operations. Also trailers provide today many additional helpers to support the driver in this role.
Since truck and trailer OEM develop independently finally the fleets and there drivers face a vehicle combination with somehow identical but separated systems. One great example is the separated air suspension systems in truck and trailer. Another example is the sepa-rated tire pressure monitoring. This situation leads to a significant increase of information, displays, interfaces the truck driver has to observe and to operate. Even with newer wire-less access systems the driver has to switch access between truck and trailer all the time.
Looking at all these facts does it make sense to leave all the communication and decision making between these helpers to the driver? Or are these systems developed enough to take the right decision? What chance has a driver to judge and overrule system decisions in the future? The driver who had become more unexperienced with each new helper on his side?
One first step to really support the truck driver in this situation could be the integration of truck and trailer systems information. Another option would be the consequent develop-ment of integrated controls and communications right from factory.
Such scenario requires extended options for communication and information exchange.
Truck – trailer communication
Communication on technical system level in modern commercial vehicles is a complex and in the area of communication between truck and trailer neglected area. While the local data communication in trucks as well as in the trailers is very sophisticated based on CAN data busses the communication between the parts of a vehicle combination is very limited. ISO 11992 is the common standard in Europe describing the communication standards be-tween truck and trailer. But ISO11992 is limited to specific control systems. The protocol includes few information about the brake or climate control system or limited loading infor-mation. There are a couple more proprietary solutions for single applications but nothing comprehensive, neither on bandwidth, protocol or even security.
The external access to the CAN data bus of European trucks is limited by the FMS (Fleet Management Service) Interface. But even with FMS as a standard not all trucks especially older trucks have the interface available. Is it available does not mean all the data stand-ardized in FMS protocol will be provided. It depends on the OEM what will be delivered.
The situation to access trailer information is not much better. External access to the trailer system depends on the manufacturer of the ABS/EBS system as provider of the basic ve-hicle controller and proprietary CAN Data bus protocols. Other systems usually use their proprietary frequencies to transfer information to the driver. Newer concepts provide al-most unsecured access using single WLAN connections to the trailer. Such solutions are usually copying consumer network applications (or even using such devices directly). This is basically a promising approach but many do neither meet any vehicle manufacturer reli-ability standard nor barely the security standards of the network industry.
LVN - Local Vehicle Network
The approach to do a first step in the direction of supporting the driver by removing unnec-essary "communication" tasks requires the development of an in-vehicle communication network for vehicle combinations of two or more units. Since this is usually a situation in commercial trucking the stakeholders should be found in that business. In reality truck and trailer manufacturer are not much talking about communication between their products. On one hand there is just knowledge about the other party missing. On the other hand the run for vehicle data has been started and nobody wants to give anything away too early even not knowing what to do with the upcoming new information flood.
One first step to support the truck driver in this situation could be the integration of truck and trailer systems information. There is reliable, secure and efficient communication channel required, a Local Vehicle Network (LVN) as the network for vehicle combinations.
Since vehicle combinations consist of two or more legally and logistically separated vehicle units there are some basic parameters and functionalities such LVN should provide.
Important parameter is the network technique with frequency and protocol. The easiest and today most promising foundation for LVN seems to be a WLAN network. WLAN net-work solutions are reliable and come with established protocols and techniques. The ac-cessibility of a LVN via consumer standards following the WLAN protocol 802.11 at 2.4 GHz will be important to connect easily to available devices like smartphones or common computers and hotspots. It will also be extendable to other frequencies using the same protocols on 5.4GHz. This allows the further extension for future vehicle to vehicle or to environment communication (V2X) using e.g. protocol variations like 802.11 p on 5.4 GHz.
An important functionality and security aspect to support the usage of such LVN will be an automated pairing process protected by physical handshake and secured access. Because of the diversity in the market the definition and agreement of a common communication protocol, frequency and pairing process will be the greatest challenge on the path to LVN. This requires knowledge in both fields, trucks and trailers and OEMs from both worlds does not seem prepared today. Establishing such network generates also extended data exchange requiring advanced solutions for data exchange, storage and access security. Providing one source of information for the whole vehicle combination allows centralizing the access of all data and sensor information of the two connected vehicles.
Last but not least LVN will be an important prerequisite for automated or autonomous driv-ing. Nobody can really believe that any autonomous driving vehicle combination will further consist of two separated units just driving the same path. The main target to provide effi-cient transport and logistic solutions leads to further automation of transport possibly hap-pening before area-wide implementation in passenger cars. Transport efficiency calls for comprehensive use of the vehicle combination something many fleets still dream of when truck OEM understand trailers as some necessary evil behind the main product. Future upcoming automation scenarios replacing the driver step by step will not be possible with-out central data access and exchange.
But even before the driver of commercial trucks may totally disappear he could be sup-ported by reducing the innumerable situations where he is just the communicator between two vehicle units forced to make decisions he is not qualified enough or even not required. Controlling the drive height of a vehicle combination makes only sense if the whole combi-nation will be controlled at the same time. Nobody would expect driver’s intervention during critical stability situations of the vehicle except of steering the right path. Interval braking during ABS is usually counterproductive.
All this demonstrates that many of today’s driver assistance systems focus often on the driver than on operating the vehicle. On one hand it is a heritage converting passenger car systems into commercial truck/trailer systems on the other side it is just because the driver is available. Support for the driver should reduce the endless number of interfaces and re-quirements for interaction saving money and equipment focussing on transportation effi-ciency.
The main communicational requirements will be
- Automated pairing process of truck & trailer without driver involvement
- One common network for the whole combination (WDS concept)
- Multi stage safety concept
- Data layer with access to all signals for whole vehicle combination
Benefit from Local Vehicle Network
Finally established an LVN will provide the foundation for many new system functions and information by connecting existing control systems in truck and trailer. Extended system access will support legal, diagnostic and logistical demands.
Assistant and control systems can certainly be the first group among many scenarios and functions already waiting for improvements. There are applications just improving or ex-tending today’s available information for the driver.
- Displaying a rear view camera image wireless directly in the cabin
- Controlled ramp approach
- Ability to deliver 360° information on vehicle combination
- Direct information on o cooling temperature
- load securing devices
- door status
Interesting are trailer data not transmitted to the truck today. The reefer temperature moni-toring is important to ensure the cooling chain and in growing amount of cases it is even required to document this value. Separated from the truck and hardly accessible for truck telematics system it requires separated an additional telematics solution for the trailer. In a similar way also other information can be used like the door status (anti-theft) and load se-curing measures.
A future stability control system on the truck may react to the trailer if one of the tension belts got loose. Stability system can improve their function with having all individual wheel speeds available or knowing the articulation angle. Future trailers will have additional sen-sors or cameras to allow automated maneuvering function like a docking pilot. All these sensor information needs to be available in the leading truck. Examples reach from ultra-sonic sensors to rearview cameras.
Benefits can be generated using information from all included vehicle units to improve al-ready available functionalities.
- Accessibility of Total Vehicle Mass during loading for personal
- Control functions like ESC & RSC are improved
- Automated pre-trip inspection
- Reduced number of telematics systems
It will also provide information for new functionalities and services.
- online Axle Load Monitoring for legal authorities
- Dynamic Drive Height Control
- availability of low cost telematics on Hotspots and with Smartphone
- online logistics at distribution centres
- Anticipatory maintenance strategies
Today’s drivers are challenged by the increasing flood of information and decisions they have to make not receiving enough information at the time. Most of the tasks require in-creased knowledge about the subjects but for many decisions the driver is not needed.
LVN between truck & trailer will be a necessary enabler for new functionalities in trucking and logistics in the future. It will be an important prerequisite for automated or driverless scenarios and base layer for V2X and extended telematic services.
A future LVN for commercial vehicles requires access to already available network solu-tions and should provide secured and automated pairing & data access. This foundation would allow to reduce the information flow to the driver changing today’s driver assistant systems into future driving assistant systems.
Author of the article
Dipl.-Ing. Thomas Wolf , Dr.-Ing. Thomas Dieckmann
WABCO Technological Innovation