Munich, Germany, July 16, 2021 – Alps Alpine has a developed an electronic control unit (ECU)1 for hands-off detection to support autonomous driving systems by distinguishing between variations in a driver’s grip on the steering wheel. Mass production began in spring 2021 and the plan is to gradually expand deployment to a range of vehicle models. To accommodate advancements in autonomous driving support and further contribute to safe and comfortable mobility, development for next-generation models is already underway.
Background to the Development
Technological innovation is gathering speed within the automotive
CASE domains of connected cars, autonomous driving, sharing and
services, and electrification. In the field of autonomous driving, we
see growing deployment of systems that enable a vehicle, under certain
conditions, to automatically follow the car in front while keeping to
the lane. One recently developed advanced autonomous driving system now
on the market performs all driving tasks under limited scenarios, such
as while traveling on an expressway or at low speeds.
Vehicles equipped with these features need to be able to detect and assess a driver’s driving status to allow safe and smooth switching between automated and manual driving. One aspect is hands-off detection, a function for determining the status of the driver’s grip on the steering wheel that interacts with other systems for assessing driving status to enable safe switching between driver-controlled and system-controlled modes. Safety features are necessary given the ongoing sophistication of autonomous driving assistance systems, and legislation is progressing. Provisions under the R79 international regulation are one example.
Determining the right time to switch between autonomous driving assistance and manual driving requires constant monitoring of the vehicle’s drive status and the driver’s driving posture to ensure safety. If the continuation of autonomous driving assistance is deemed inappropriate, the driver needs to be quickly warned that the assistance is to be disengaged and urged to immediately revert to manual driving. Safety assurances demand much more precise detection of diverse variations of the driver’s grip on the steering wheel.
Outline of the Development
1. System Configuration
Capacitive sensing
is the dominant technology used for steering wheel touch detection due
to its cost and functional performance. The ECU uses data obtained via a
special-purpose capacitive sensor, wrapped around the steering wheel, to
determine if the driver is touching it and conveys the assessment to an
advanced driver assistance system (ADAS). Whereas existing hands-off
detection systems are mono-zone setups, with a single electrode, Alps
Alpine has developed a multi-zone configuration with four electrodes
(see Fig. 1). Dividing the steering wheel and grip patterns into smaller
sections enables efficient system switching and enhanced touch
assessment reliability.
Fig.1
2. Product Outline
Resilience to physical stress is a
necessary consideration when employing capacitive control, as is the
need to maintain resistance to environmental factors – temperature,
humidity and electromagnetic noise – and the feel of the sensor itself.
It is also essential to have separate, optimal control for sensor
materials specific to the application. Alps Alpine started producing
touch panels for notebook PCs and game consoles in the 1990s and
automotive control panels for capacitive touch-type in-vehicle
infotainment (IVI) systems in the 2010s. The company has plenty of
experience applying capacitive control technology to a diverse range of
sensor materials and environments spanning product domains from consumer
electronics to automobiles. Utilizing this knowledge, we have developed
a hands-off detection ECU for use with a specialpurpose steering wheel
capacitive sensor. Deliveries to steering wheel manufacturers began in
spring 2021.
1)
Industry-first four-electrode sensor (see Fig. 1)
The sensor
electrode is divided into four sections to enable identification of
various grip states. This allows a more detailed assessment of driving
status than a basic touching/not touching determination reached using
an existing single-electrode sensor.
2)
Original capacitive control ASIC2
Alps Alpine has
developed an original capacitive control ASIC with improved durability
and versatility for conformance to strict automotive standards.
3)
Steering wheel design, sensor material, electromagnetic compatibility3…conditions vary from model to model, leading to variance in data obtained via the capacitive sensor. To accommodate the separate circumstances, Alps Alpine can supply an originally developed algorithm that seeks individual optimization, for example with parameter changes.
4)
Failure self-diagnosis function
Reliability is enhanced by an
original failure determination feature and the product conforms to ISO
26262, the international standard on the functional safety of
electrical and electronic systems in automobiles.
Outlook
By fiscal 2025, we can expect further advancements among autonomous driving assistance features and needs for hands-off detection are predicted to grow all over the world. The success of this product’s development forms a base on which to approach automobile and steering wheel manufacturers with product proposals and expand sales. Alps Alpine will also put forward product proposals, representing examples of applied capacitive technology, for a wide range of human-machine interfaces (HMI) both inside and outside the vehicle cabin, not just hands-off detection. This is part of our contribution to safe and comfortable automobile-based mobility.