Haptic Guidance Needs to Be Intuitive Not Just Informative to Improve Human Motor Accuracy

Communication and Interaction With Semiautonomous Ground Vehicles by Force Control Steering

While full automation of road vehicles remains a future goal, shared-control and semiautonomous driving-involving transitions of control between the human and the machine-are more feasible objectives in the near term. These alternative driving modes will benefit from new research toward novel steering control devices, more suitably where machine intelligence only partially controls the vehicle. In this article, it is proposed that when the human shares the control of a vehicle with an autonomous or semiautonomous system, a force control, or nondisplacement steering wheel (i.e., a steering wheel which does not rotate but detects the applied torque by the human driver) can be advantageous under certain schemes: tight rein or loose rein modes according to the H -metaphor. We support this proposition with the first experiments to the best of our knowledge, in which human participants drove in a simulated road scene with a force control steering wheel (FCSW). The experiments exhibited that humans can adapt promptly to force control steering and are able to control the vehicle smoothly. Different transfer functions are tested, which translate the applied torque at the FCSW to the steering angle at the wheels of the vehicle; it is shown that fractional order transfer functions increment steering stability and control accuracy when using a force control device. The transition of control experiments is also performed with both: a conventional and an FCSW. This prototypical steering system can be realized via steer-by-wire controls, which are already incorporated in commercially available vehicles.

Minute hands of clocks indicating the same time are not perceived as haptically parallel

Many studies have already shown that a large idiosyncratic orientation difference is needed to perceive two bars that are far apart as haptically parallel. There exist also strong indications that if such bars are imagined to be minute hands of clocks, errors made in clock time estimates and clock time settings are much smaller. The current study investigated this seemingly discrepancy. Participants partook in three experiments: parallel setting, clock time estimate and clock time setting, in this order. As the individual parallel settings were used in the subsequent clock time estimate experiment, and the estimated clock times in the clock time setting experiment, the deviations could be compared directly. In all three experiments, the deviations were systematic and idiosyncratic, and consistent with a biasing influence of an egocentric reference frame. However, the deviations in the two clock time experiments were indeed much smaller than in the parallel setting experiment. Task instruction and strengthened focus on an allocentric reference frame are the most likely explanations. These findings provide fundamental insights in the processing of spatial information. Taking these findings into account when designing haptic devices may make these more intuitive.

Correcting for Visuo-Haptic Biases in 3D Haptic Guidance

Visuo-haptic biases are observed when bringing your unseen hand to a visual target. The biases are different between, but consistent within participants. We investigated the usefulness of adjusting haptic guidance to these user-specific biases in aligning haptic and visual perception. By adjusting haptic guidance according to the biases, we aimed to reduce the conflict between the modalities. We first measured the biases using an adaptive procedure. Next, we measured performance in a pointing task using three conditions: 1) visual images that were adjusted to user-specific biases, without haptic guidance, 2) veridical visual images combined with haptic guidance, and 3) shifted visual images combined with haptic guidance. Adding haptic guidance increased precision. Combining haptic guidance with user-specific visual information yielded the highest accuracy and the lowest level of conflict with the guidance at the end point. These results show the potential of correcting for user-specific perceptual biases when designing haptic guidance.