Sharing Control With Haptics

Delft University of Technology, Kluyverweg 1, 2629 HS Delft, The Netherlands.
Human Factors The Journal of the Human Factors and Ergonomics Society (Impact Factor: 1.69). 10/2012; 54(5):786-98. DOI: 10.1177/0018720812443984
Source: PubMed


Haptic shared control was investigated as a human-machine interface that can intuitively share control between drivers and an automatic controller for curve negotiation.
As long as automation systems are not fully reliable, a role remains for the driver to be vigilant to the system and the environment to catch any automation errors. The conventional binary switches between supervisory and manual control has many known issues, and haptic shared control is a promising alternative.
A total of 42 respondents of varying age and driving experience participated in a driving experiment in a fixed-base simulator, in which curve negotiation behavior during shared control was compared to during manual control, as well as to three haptic tunings of an automatic controller without driver intervention.
Under the experimental conditions studied, the main beneficial effect of haptic shared control compared to manual control was that less control activity (16% in steering wheel reversal rate, 15% in standard deviation of steering wheel angle) was needed for realizing an improved safety performance (e.g., 11% in peak lateral error). Full automation removed the need for any human control activity and improved safety performance (e.g., 35% in peak lateral error) but put the human in a supervisory position.
Haptic shared control kept the driver in the loop, with enhanced performance at reduced control activity, mitigating the known issues that plague full automation.
Haptic support for vehicular control ultimately seeks to intuitively combine human intelligence and creativity with the benefits of automation systems.

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    • "Even when desired trajectories are similar but not identical between operator and shared controller [5], [24], repetitive small trajectory conflicts can occur between human operator and haptic shared controller. Such conflicts are reported to be annoying [5], and may lead to momentary increases in force [21], [24]– [27], discomfort or even deteriorated performance [4], [19], [21]. How to best mitigate or resolve these skillbased conflicts (e.g., in terms of trajectories) is still an open question. "
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    ABSTRACT: Haptic shared control can improve execution of teleoperation and driving tasks. However, shared control designs may suffer from conflicts between individual human operators and constant haptic assistance when their desired trajectories differ, leading to momentarily increased forces, discomfort or even deteriorated performance. This study investigates ways to reduce conflicts between individual human operators and a haptic shared controller by modifying supported trajectories. Subjects (n=12) performed a repetitive movement task in an abstract environment with varying spatio-temporal constraints, both during manual control and while supported by haptic shared control. Four types of haptic shared control were compared, combining two design properties: the initial supported trajectory (either the centerline of the environment or an individualized trajectory based on manual control trials), and trial-by-trial adaptation of guidance towards previously performed trajectories (either present or absent). Trial-by-trial adaptation of guidance reduced conflicts compared to non-adaptive guidance, whether the initial trajectory was individualized or not. Without trial-by-trial adaptation, individualized trajectories also reduced conflicts, but not completely: when guided, operators adapt their preferred trajectories. In conclusion, trial-by-trial adaptation is the most promising approach to mitigate conflicts during repetitive motion tasks.
    No preview · Article · Sep 2015
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    • "This action influences the vehicle's lateral position and, at the same time, provides continuous haptic guidance to the driver, who remains in the control loop. The advantages of shared control over manual control in terms of lane-keeping performance, reaction times, comfort and workload associated with a secondary task have been demonstrated repeatedly [4]– [7]. However, longitudinal studies of how drivers adapt to SC systems are still lacking. "
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    ABSTRACT: Although the benefits of haptic shared control of the steering wheel have been repeatedly demonstrated, longitudinal studies of how drivers adapt to this kind of system are still lacking. The present study addressed this question by comparing two groups of participants in a driving simulator for an extended time period; one group drove with a shared control system and the other drove without. After the practice, all participants drove a final trial with shared control during which a failure of the system occurred. The results show that the evolution of driving performance and the way in which drivers monitored their performance was similar for the two groups. This suggests that the drivers quickly updated their internal model of the steering system dynamics at the sensorimotor level, without further behavioural adaptation afterwards. However, it appears that the internal model was consolidated with repeated use of the system, which translated as a difficulty to compensate for the system's failure. In addition, it appears that drivers did not attempt to maintain a level of task difficulty when steering was facilitated.
    Full-text · Conference Paper · Oct 2014
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    • "Times of pressing and releasing the mouse buttons were recorded. Vehicle dynamics were identical to those used in earlier studies with this simulator (de Winter, Mulder, Van Paassen, Abbink, & Wieringa, 2008; Mulder et al., 2008, 2012). In all driving conditions, the steering wheel provided a mild centering torque, being a monotonic function of the steering wheel angle. "
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    ABSTRACT: The aim of this study was to compare continuous versus bandwidth haptic steering guidance in terms of lane-keeping behavior, aftereffects, and satisfaction. An important human factors question is whether operators should be supported continuously or only when tolerance limits are exceeded. We aimed to clarify this issue for haptic steering guidance by investigating costs and benefits of both approaches in a driving simulator. Thirty-two participants drove five trials, each with a different level of haptic support: no guidance (Manual); guidance outside a 0.5-m bandwidth (Band1); a hysteresis version of Band1, which guided back to the lane center once triggered (Band2); continuous guidance (Cont); and Cont with double feedback gain (ContS). Participants performed a reaction time task while driving. Toward the end of each trial, the guidance was unexpectedly disabled to investigate aftereffects. All four guidance systems prevented large lateral errors (>0.7 m). Cont and especially ContS yielded smaller lateral errors and higher time to line crossing than Manual, Band1, and Band2. Cont and ContS yielded short-lasting aftereffects, whereas Band1 and Band2 did not. Cont yielded higher self-reported satisfaction and faster reaction times than Band1. Continuous and bandwidth guidance both prevent large driver errors. Continuous guidance yields improved performance and satisfaction over bandwidth guidance at the cost of aftereffects and variability in driver torque (indicating human-automation conflicts). The presented results are useful for designers of haptic guidance systems and support critical thinking about the costs and benefits of automation support systems.
    Full-text · Article · Feb 2014 · Human Factors The Journal of the Human Factors and Ergonomics Society
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