MOTOR Magazine

A MOTOR Magazine Newsletter
August 22, 2018

Contributed by Bob Chabot
Sensing Drives Automated Mobility

Automated vehicles must be able to sense, think and act

In order to drive autonomously and safely, self-driving cars need to be focused on their surroundings with the aid of their various surround sensors. Comprised of cameras, radar, lidar, ultrasonic and others, these sensors are the eyes and ears of an automated car and supply all the information required by the vehicle to perceive its environment.

Taken together, Bosch says the vehicle will then be able to provide a solid basis of information for the smart vehicle computer, which it uses for exact calculations. In addition, because automated vehicles can detect monotonous situations like traffic jams and take over repetitive driving tasks, drivers reach their destination more relaxed. Bosch Mobility recently shared with MOTOR what it views as the key sensing tenets to enable automated driving to be fully implemented.

Here’s an overview of the various sensor technologies that will survey and analyze the vehicle’s surroundings. (All images — Bosch Mobility)

Sensing Surroundings and Situations
Automated cars must be aware of even more than their immediate surroundings: using up-to-date, high-resolution digital maps and connected real-time data from the cloud, the vehicle can also access external information such as traffic or weather data.

Also, some sensors are aligned inward into the passenger compartment, enabling the system to make autonomous decisions as to whether the driver is capable of taking control of the vehicle again if necessary. As the vehicle moves autonomously in real traffic situations, it must be able to detect and localize all relevant road users within the entire vehicle environment (360 degrees). To improve the reliability and stability of information, several other sensors (e.g. pressure, accelerometer) are required that apply various surveying principles to monitor each area of the vehicle’s surroundings.

Most of the sensors required for these tasks are already in volume production today. For example, partially automated systems which support drivers in difficult situations are already available. These include remote park assist, garage park assist, home zone park assist, traffic jam assist or highway assist.

In certain cases, lidar, radar, video and ultrasonic sensors are not sufficient to constantly deliver plausible data of two sensors. This is why Bosch is working on new sensor technologies to meet the high demands on surroundings perception. The data provided by these new individual sensors will be combined and processed to form a comprehensive environmental model representing all static and dynamic objects. Entirely new hardware and software technologies and new algorithms are used for this calculation.

Various sensor technologies cover the entire vehicle surroundings in three distinct layers:

  • A localization layer, which determines the position of the vehicle in the lane and contains the road signature based on radar and video sensors.
  • A planning layer that forms the basis for calculating individual driving maneuvers and contains information on lanes, traffic signs, speed limits, curve radii and gradients.
  • A dynamic layer that contains information on all fast-changing conditions such as traffic jams, road work and hazard zones, available parking spaces and even the weather (e.g. current road conditions such as rain, ice and snow).

Accurate Mapping is Essential
A matrix of sensors, digital maps and connectivity heighten the car’s sense of orientation. For instance, high-definition digital maps point automated vehicles in the right direction. For highly and fully automated driving to be realized, the mapping that provides vehicle localization and awareness must be both exact and constantly available.

The high-definition digital maps used for this purpose contain far more layers of information than the maps for standard satellite navigation devices. They also support the automated vehicle in planning individual driving maneuvers (e.g. whether the vehicle should change lanes or not).

A single sensor is unable to fulfill these requirements, which is why a combination of surround sensors (for detecting landmarks such as lane markings and buildings) with satellite navigation and correction service as well as inertial sensors and a digital map is used. Through connectivity with the cloud, the data contained in the maps is constantly updated, enabling inclusion of dynamic factors such as temporary closed lanes in travel plans. For the so-called road signature, Bosch has developed a pioneering solution for creating and updating key parts of high-definition maps using vehicles’ radar, video and other sensors, literally as they drive by.

The first levels of automated driving are already a reality and are paving the way for mobility of the future. As vehicles become more connected in real time to each other and their surrounding driving environment, mobility will be enhanced.

Connected Road Condition Services Enable Automated Cars to Drive Even Better
Information on current road conditions is also required by automated vehicles to detect potential dangers at an early stage and to ensure safety during driving. For these innovative road condition services, Bosch uses weather data supplied by its partner, Foreca, in a first expansion stage, to draw conclusions about possible hazards such as aquaplaning, ice or snow. Automated cars can then adapt their driving behavior to the respective conditions, choose a different route or ask the driver to take control if a safe onward journey cannot be guaranteed in automated mode.

In the future, Bosch says it will begin supplementing its predictive road condition services to include data from the vehicle. What inside and outside temperatures are measured by the car? Are the wipers activated? Connectivity means that such information does not stay unused in the vehicle but reaches the cloud through the respective manufacturer’s backend. Bosch also evaluates the control interventions by its antilock ESP skid protection system to determine the friction value and condition of the road surface. All data combined and evaluated intelligently results in a feeling of safe automated driving.

Self-driving vehicles will constantly monitor whether the driver is capable of taking back control when necessary. If not, the vehicle has built-in redundancy algorithms to keep control and safely bring the vehicle to a stop.

Sensors Monitoring Drivers Will Optimize Vehicle Control and Occupant Safety
Highly and fully automated functions need to monitor the driver as well as the vehicle’s surroundings in case the driver does not take control when necessary. Drivers won’t be obliged to monitor the system when these functions are in operation. They can pass full control to the system, at least for a certain period of time or for a defined situation, after which the driver is requested to take control of the driving task – and the vehicle must be able to detect if the driver is capable of doing so. Bosch has already developed systems such as driver drowsiness detection, which constantly monitors the driver and issue warnings in dangerous situations such as fatigue or microsleep.

The system passing driving responsibility to the driver remains a challenge for engineers. How is the driver informed, how long does the driver need to take over? What happens if the driver does not take control? One possible scenario: If the driver fails to take over, even after multiple alerts, as the car approaches a freeway exit, the automated vehicle would stop autonomously on the hard shoulder.

Self-driving vehicles will constantly monitor whether the driver is capable of taking back control when necessary. If not, the vehicle has built-in redundancy algorithms to keep control and safely bring the vehicle to a stop. For example, a schematic of the redundant steering system already on some Bosch-equipped vehicles is shown above.

Redundant Systems that Protect Automated Vehicles from Failures
For highly and fully automated driving, drivers no longer need to monitor the system. When automated vehicles assume the driving responsibility, there is also the question of safety that needs to be addressed. Although the risk of failure by the system and individual components can be reduced to a minimum – it cannot be entirely eliminated. In the event of a system failure, it must therefore be possible for the vehicle to achieve a safe state even without intervention by the driver.

For this reason, Bosch has developed solutions which safeguard the automated system against malfunctions. Safety-critical sub-systems such as steering, braking, onboard power supply system and data processing have a redundant design and are controlled independently. This means that when one system fails, another independent system is always capable of assuming the respective task and bringing the vehicle to a safe standstill in a critical situation.

For example, Bosch already offers a redundant solution for safeguarding the braking system: independently of each other, the iBooster, an electromechanical brake booster, and the ESP® brake control system can decelerate the vehicle to a standstill without requiring intervention by the driver. The steering system is also a key technology for automated driving. With its Servolectric electric power steering, Bosch has developed a steering solution, which meets all the safety requirements associated with highly automated driving.

To be viable, automated vehicles must have three fundamental capabilities:

  • They need to perceive and interpret (i.e. sense) their surroundings.
  • They need to use this information to make forecasts and derive a suitable driving strategy (i.e. think).
  • They must be able implement the data reliably and safely (i.e. act).

The Three Steps to Safe Automated Driving are Sense, Think and Act
Sensing the immediate environment is the task of the surround sensors which combines camera, radar and ultrasonic. Vehicle intelligence enabling it to interpret its surroundings and find the optimal driving strategy is made possible by software and algorithms, which use the information gleaned from sensors as well as data from other connected systems.

Systems such as the powertrain, steering and brakes ensure that the respective driving strategy is then implemented on the road. This process of sensing, thinking and acting takes place during the entire journey. When applied to human beings, this process is similar to constant interactions in the body during which the sensory organs pick up stimuli, which are processed by the brain before the nerve pathways, muscles and limbs implement the brain’s control signals as actions.

Bosch Mobility says its intention is to enable a safe and relaxing drive in a self-driving automobile. Using sensory data of the car’s surroundings, fully automated vehicles will provide more efficient mobility, detect critical situations faster and avoid them better than human drivers, resulting in fewer accidents.

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