November 24th 2011

Tom Wellings Lead EngineerWMG, University of Warwick

Human Machine Interfaces in Low Carbon VehiclesFindings from the CABLED trial

Low Carbon Vehicle Technology Project: Workstream 13

Workstream members

WMG, The University of Warwick (project lead)

Tom WellingsProf. Mark WilliamsDr. Alex Attridge

Jaguar Land Rover Research Duncan RobertsonLee SkrypchukDr. Carl Pickering

Coventry University School of Art and Design

Dr. Jackie BinnersleyProf. Andree WoodcockProf. Mike Tovey

Tata Motors European Technology Centre

Tawhid Khan

What are Human Machine Interfaces?

• Any point at which a user interacts with the vehicle

• HMI enables control of the car itself, and of in-car technologies

• HMI also feeds back information about the vehicle's state to the driver

Why is HMI important?

• HMI design is a strategic differentiator for OEMs

• LCVs will introduce new technologies and issues for the user

• Safety implications

• The experience of interacting with the HMI needs to be positive to increase adoption of LCVs

• Consumers' desire for advanced telematics and connected services

• Customers are spending longer periods of time inside their cars

User centred approach

Agree research objectives based on partners’ requirementsTask 13.1

Identify sources of existing LCV user data specific to HMI. Analyse data, and prioritise main design issues that need addressing

Task 13.2

Select participants and trial methods for capturing user feedback from LCV users

Task 13.3

Collect primary data from LCV usersTask 13.4

Analyse primary data from LCV users. Identify key issues and possible solutions

Task 13.5

Build HMI driving simulator, and trial prototype HMI solutionsTask 13.6

Aim and objectives

Aim: To identify the key HMI concerns and appropriate solutions specific to users of Low Carbon Vehicles

• Conduct dedicated user-centred research to investigate owners’ experience of driving LCVs. The emphasis will be on HMI needs and driver behaviour.

• Build a driving simulator to conduct user trials on concept HMI. The focus will be on evaluating the user experience and acceptance of new technologies

Priority

Priority

Task 13.2 – Findings: User issues

Category Issue Design problems raised from the research findings

Range Anxiety Range anxiety due to fear of running out of charge

What HMI changes/new features can OEMs implement in order to reduce range anxiety?

Range anxiety reducing with experience

What HMI changes/new features can OEMs introduce to 'speed-up' this reduction in range anxiety?

Charging Problems with charging What is the optimal HMI design for vehicle charging feedback? Location on the vehicle? What charging states? Feedback time-out?

Frequency of charging What is the best way that the OEM can remind (but not nag) the user to charge the vehicle?

Location of charging point What is the best way for the OEM to inform the driver of the location of charging points in the near vicinity?

Feedback Unreliable information about range and charging

What are the 'HMI rules' that any range or charging information should abide by in order to promote confidence in the data?

Lack of engine noise What is the most appropriate method of compensating for the lack of engine noise as a form of driver feedback?

Adapting behaviour

Optimising range In what way can drivers be encouraged to safely adapt their driving style or chosen routes, such that efficiency is improved?

One-foot driving What are the implications (if any) of 'one-foot driving' on the design and engineering of the accelerator and braking pedals?

Task 13.2 - Deliverables

HMI 2.0 report

Data collection instruments for CABLED trial

Theme Research Questions

Range anxiety and lack of confidence in feedback

Is the occurrence of range anxiety related to familiarity with the vehicle?

In what way is battery charge information conveyed to the driver?Does the battery charge information meet the drivers expectation and needs

In what way is range information conveyed to the driver? Do they trust this information?Does the range information meet the drivers expectation and needs

The charging process

How long does it take customers to fully charge their vehicle, and do they think this is satisfactory?

Did customers forget to charge the vehicle at any time?

How often do customers use public charging stations, and does this change over time?

How can the act of plugging in and setting the vehicle to charge be improved for the customer?

User adaptation to eco-driving

What are the benefits of having an 'economy mode'? Note: economy mode is a feature which turns off the vehicle's systems/features in order to maximise the vehicle's range

How can driver behaviour (i.e. things the driver has control over) influence the economy of low carbon vehicles?

Other user-issues concerning vehicle

feedback

Are drivers aware of the vehicle's state, i.e. on and ready to be driven, or turned off.

When customers are not in their vehicle, what information about it do they want to know?

How useful is the information provided to the driver when using the vehicle

• Questionnaires, Interview and focus group - based on the themes identified in Task 13.2

Main research topics

User Issue to be investigated Description of data classified in this theme

Design problems from Task 1 research findings

1 Range anxiety and lack of confidence in estimated range, and state of charge feedback.

User issues where feedback of estimated range, or state of charge information to the driver was deemed unpredictable.

E.g. due to outside temperature, chosen route, use of ancillary systems, inaccurate calculation

What are the 'HMI rules' that any range or charging information should abide by in order to promote confidence in the data?

2 Problems with the process of charging, frequency of charging, and reminding users to recharge.

Issues related to vehicles failing to charge, low charge warnings, diagnosis of faults, location of the charging socket, and problems with plugging-in

What is the optimal design of HMI for vehicle charging feedback?

What's the best way that the OEM can remind the user to charge the vehicle?

Trial vehicles - Mitsubishi iMiEV

Power in/out gauge with eco-zone

Battery state of charge (SOC) dial with 16 segments

Estimated range display - calculated from consumption of electricity for the last 15 miles driven + air conditioning usage

A low energy warning indicator flashes when only 2 segments remain visible

Power down warning lamp - will light up when the battery energy level becomes zero

Trial vehicles - Smart fortwo Electric Drive

The primary HMI associated with the powertrain are two analogue dials on top of the instrument panel.

Battery state of charge (SOC)From 0-20% the dial is coloured red/orange

Power in/out gauge - the needle moves anticlockwise when energy is being recovered through regenerative braking, and clockwise when energy is being used (+10kW to -30kW)

LCD message display shows the proportion of the motor's maximum power (in KW) that is capable of being delivered

No specific feedback for estimated range

Trial vehicles - Tata Vista EV

The primary HMI associated with the powertrain are two analogue dials within the instrument cluster.

Power in/out gauge - the needle moves anticlockwise (past the 12 o'clock position) when energy is being recovered through regenerative braking, and clockwise when energy is being used

Battery state of charge (SOC)From 0-10% the dial is coloured red, from 10-20% the dial is coloured orange.

No specific feedback for estimated range

Methodology

• Data was collected using questionnaires and interviews.

> In collaboration with Oxford Brookes University

• Data collected at different points in time – pre-use, 1 week experience, 3+ months experience

Mitsubishii-MiEV

Smart fortwo

Tata vista Total

Pre-trial questionnaire 0 6 18 24

Interview 4 10 6 20

Post-trial questionnaire 17 9 15 41

Limitations in the data:

• Delays in vehicle availability for participants led to some missing data

• Some participants had completed trials before HMI questions could be incorporated

Findings: Range anxiety and lack of confidence in feedback

Not all the vehicles provided an estimated range - most drivers wanted this

• Trust in estimated range was split (61% trusted it, 32% didn’t trust it, 7% no opinion)

“The remaining range indicator is not accurate. It might read 60 and after half a mile it drops to 55 - this means you can never have confidence in it.”

‘Unreliable’ range and state of charge feedback actually due to:

• Extreme outside temperature (cited by 77% of respondents), Driving style, Using heaters and air conditioning.

“Range predicted does not properly account for driving style or use of heat/ fan/ lights. It tends to overestimate range left.

Recommendations:

• Investigate different ways to present information about range and state of charge to drivers

• EV drivers need dynamic information on factors that influence available range

• Range display should take account of external temperature, use of climate system, and route.

Findings: Range anxiety and lack of confidence in feedback

Guidance for maximising economy

• 78% of drivers said it was important to understand how their driving behaviour can maximise economy

Recommendations:

• Provide guidance/training on how to drive economically – in-car at the minimum

• Investigate different ways to present information about range and state of charge to drivers

Location of information

Participants who agreed

Participants who disagreed

Participants who did not express an opinion

Total

In-car 100% 0% 0% 100%

On the web 54% 17% 29% 100%

Driver`s manual 56% 12% 32% 100%

Smart phone 37% 29% 34% 100%

Where would be an effective location for displaying guidance on maximising economy?

Sample size = 41

Findings: Range anxiety and lack of confidence in feedback

Eco-feedback

• Eco-feedback interfaces which aim to encourage more efficient driving behaviour are likely to become more commonplace

• Fuel savings in the order of 6% to 15% can be achieved

• OEMs that implement these systems well, can differentiate their brand, and provide real benefits to users

• Combining goal-setting with feedback has proved to be a particularly effective strategy for encouraging behaviour change

• These principles have been most successfully applied in the Ford SmartGauge interface as found in the Fusion hybrid, and the LCD cluster in the Chevrolet Volt

> Drivers finding the SmartGauge rewarding, and useful for maximising fuel economy.

Findings: Range anxiety and lack of confidence in feedback

Remote access to vehicle information

How useful it would be to have access to certain types of information when away from the vehicle?

"I think there should be a little key fob or something that you carry with you […] that shows you how charged up your car is […] just to give you some sort of security and comfort that you’re not going to get back to your car and find that it’s not charged."

Recommendations

• Provide remote access to information about range, and charging progress

• Remind users to recharge

Sample size = 20

Type of information Participants who thought it would be useful

Participants who did not think it would be useful

Participants who did not express an opinion

Total

Range 85% 10% 5% 100%

Charging progress e.g. charging finished 75% 20% 5% 100%

Electricity cost of last charge 65% 35% 0% 100%

MPG data 60% 15% 25% 100%

Vehicle location 20% 80% 0% 100%

Findings: Problems with the process of charging

The physical charging process

• Frustration when car did not charge as expected; e.g. hardware malfunction

• Users wanted feedback indicating when charging was taking place, and the majority of drivers wanted the information to be available remotely.

• Users get frustrated if it is not easy to connect the plug to the charging socket (particularly in the dark)

"I just think it’s quite tricky to line up.…… it could be illuminated in some way. Either on the connector itself or within the fuel cap itself could be some kind of light“

• Externally visible lights showing charging progress draw attention and are seen as a security risk

Recommendations:

• Provide remote access to information on SoC and charging progress

Findings: Problems with the process of charging

Reminding users to recharge

• 27% of participants had forgotten to recharge their vehicle on at least one occasion

• Implications are greater than for IC engine cars

"It would be great if [the car] could tell you at night. 'Hey you forgot to plug me in'.”

Recommendations:

• Ensure vehicle reminds users to recharge – but without nagging

• Consider notifications in addition to in-car warning

Findings: Problems with the process of charging

Using public charging stations:

• Problems included: charging stopping for no reason, non-EV vehicles being parked in the charging bays, and people unplugging the vehicle.

“The first time I plugged in at a public charging point, some bloke or lads thought ‘oh get in’ and unplugged it”

• Not knowing where public charging stations were

Recommendations:

• Incorporate measures to prevent unauthorised unplugging when charging

• Provide drivers with in-car information about the location of charging points and their availability

• Provide remote access to information on charging progress

HMI simulator

• Industry leading Octal SCANeR Studio software – realistic 3D environment

• Jaguar XJ buck providing premium vehicle cockpit environment

• Reconfigurable instrument cluster for testing driver information concepts

• Force feedback steering system

Future work - Range display user-trial

• User Issue: Drivers say they cannot trust the vehicle feedback for range and SoC

“As I began my journey, the charge meter went down much faster than I expected it to”

“Although we had only travelled 27 miles the dial was showing we had used 34 miles.”

• Research question: Which variables governing the way the available range value is displayed are most important to instil confidence for EV drivers?

Benchmarking

HMI evaluation questionnaire

> Gather users’ opinions and feedback on the HMI in each vehicle after a drive

• Several drivers commented on the complexity and duplication of information across the instrument cluster and central display in both vehicles

Chevrolet Volt REEV Nissan Leaf EV

Benchmarking

Eco-feedback and range display

Movie describing unexpected behaviour of range display in Chevrolet Volt.

Should range value increase while you are driving?

Chevrolet Volt eco-feedback - ball moves under braking and acceleration

More sensitive to braking severity

Workstream 13 publications

Agree research objectives based on partners’ requirementsReport: WS 13 objectives + tasks_v3_TS gatewayTask 13.1

Identify sources of existing LCV user data specific to HMI. Prioritise main design issues that need addressingReports: • HMI 1.0 - LCV at Geneva motor show• HMI 2.1 - HMI in LCVs Market analysis and User issues_Public• HMI 3.0 - OEM research priorities 20110209

Task 13.2

Analyse primary data from LCV users. Identify key issues possible solutionsReport: HMI 4.1 - Task2 CABLED report 20111109Conferences: • A survey of HMI issues in electric vehicles (Transport Design and UX 2011)• HMI and the User Experience in Low Carbon Vehicles (Interact2011)• Supporting Sustainability In The Design Of Electric Vehicle Interfaces:

Lessons learnt from early adopters (Ergonomics & Human Factors 2012)

Task 13.5

Build HMI driving simulator, and trial prototype HMI solutionsReport: JRR-2011-0788 Chevrolet Volt (2011) Benchmark report Issue01

Bench-marking

OEM application of WS13 knowledge

Knowledge gathered in Workstream 13 has been used to:

• Develop the standards for HMI of Low Carbon Vehicles (JLR) :-

> ‘A’ surface – covering charging task, charging port location

> Touchscreen content - covering charging management & navigation.

> Instrument cluster content – covering new LCV elements, warning messages, content in different vehicle power modes, start-up sequence, menu content, EV mode.

> Switchgear – covering hybrid modes.

• Develop HMI concepts for EV driver information display (esp. estimated range calculation and display) [TMETC].

Questions?

Email: tom@emotivesystems.co.ukA.Attridge@warwick.ac.uk