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Haptic guidance in a shared steering assistance system has drawn significant attention in intelligent vehicle fields, owing to its mutual communication ability for vehicle control. By exerting continuous torque on the steering wheel, both the driver and support system can share lateral control of the vehicle. However, current haptic guidance steering systems demonstrate some deficiencies in assisting lane changing. This study explored a new steering interaction method, including the design and evaluation of an intention-based haptic shared steering system. Such an intention-based method can support both lane keeping and lane changing assistance, by detecting a driver's lane change intention. By using a deep learning-based method to model a driver's decision timing regarding lane crossing, an adaptive gain control method was proposed for realizing a steering control system. An intention consistency method was proposed to detect whether the driver and the system were acting towards the same target trajectories and to accurately capture the driver's intention. A driving simulator experiment was conducted to test the system performance. Participants were required to perform six trials with assistive methods and one trial without assistance. The results demonstrated that the supporting system decreased the lane departure risk in the lane keeping tasks and could support a fast and stable lane changing maneuver.

The driver steering performance is strongly related to gaze behavior in natural driving. The investigation of gaze behavior is crucial for understanding driver response to driver–automation shared control, which was developed to reduce the workload of drivers while keeping them in the control loop. This study focused on driver gaze behavior and its relationship to the steering performance when driving with different levels of shared control. Shared control was achieved through a haptic guidance steering system, which provided active assistant torques on the steering wheel. A driving simulator experiment was conducted with 15 participants, who drove five trials, each with a different level of shared control: first, no haptic guidance, second, normal haptic guidance, third, strong haptic guidance, fourth, having a driver's hands hovering over the steering wheel as a standby during automated driving, and, fifth, having a driver's hands free for a long time during automated driving. The results show a tendency that the correlation between gaze and steering movements decreased when the automation authority of shared control increased. A reduction in the lead time of gaze over steering movement was found in the condition of strong haptic guidance compared to normal haptic guidance and manual driving. This study suggests the potential of using the relationship between gaze behavior and the steering performance to analyze driver interaction with automation.

Prolonged driving on monotonous roads often leads to a reduction in task load that causes drivers passive fatigue. Passive fatigue results in loss of driver alertness and is detrimental to driver safety. This paper focuses on the effect of a haptic guidance steering system on improving behaviors of passively fatigued drivers. By continuously exerting active torque on a steering wheel, the haptic system guides drivers to follow the centerline of a lane; meanwhile, the drivers sense the torque and interact with it while operating the steering wheel. An experiment was conducted with 12 healthy participants in a high-fidelity driving simulator. A monotonous driving course was designed, and vehicle speed was fixed in order to induce drivers’ passive fatigue. A treatment session was arranged with the haptic guidance steering system, and a control session was conducted as a comparison. Driving performance, assessed by standard deviation of lane position, mean absolute lateral error, and time-to-lane crossing, was significantly improved when haptic guidance was activated. Results of physiological measures, including heart rate variability and percentage of eye closure, revealed that passively fatigued drivers were aroused when they were aware of the active torque on the steering wheel. In conclusion, the activation of haptic guidance can be regarded as an effective countermeasure for the passively fatigued drivers who have performed a prolonged monotonous driving task.

This paper deals with active boundary control (ABC) of a rectangular plate using feedforward control. Conventionally, boundary conditions dominating the fundamental properties of a structure are obtained a priori. If it is possible to control the boundary conditions of a structure, its structural characteristics may be altered as wished. The ABC presented in this work enables one to generate the desired boundary conditions at a designated area on a target plate. Firstly, the principle of the ABC where the system is described using the transfer matrix method is presented. Then, the optimal feedforward control law for producing the desired boundary conditions on the plate is derived. It is found that, as a result of applying the ABC on an edge of the plate, global generation of a quiet zone around the edge can be achieved. Numerical simulations are conducted where the fundamental properties of the ABC system are investigated. In addition, implementation of the ABC using distributed parameter polyvinylidene fluoride film (PVDF) sensors introduced for modal filtering is discussed. Finally, experiments are carried out to demonstrate the validity of the ABC when generating a desired boundary condition at the target location, creating a global quiet zone within the target region of the plate.

Recently, different nonlinear energy harvesters were designed to harvest energy from various rotational motions, which aim to provide power to self-powered wireless sensors. In this paper, a quad-stable piezoelectric energy harvester, comprising of a piezoelectric beam and magnets, is designed to enhance energy harvesting efficiency in rotational motion. In addition, a theoretical model is derived to describe the dynamic performance and the output voltage of the harvester. Furthermore, experimental results demonstrate that the presented harvester in rotational motion exhibits a wider working frequency range compared with that of the bi-stable one. Most importantly, for the rotational speed range of 60 - 420 rpm (1 - 7 HZ), the inter-well oscillation for the harvester can be achieved and corresponding peak voltage is higher than 10 V, which can be used to power wireless sensors. Overall, the quad-stable piezoelectric energy harvester is experimentally verified to be suitable for the low-frequency rotational environment.

This letter investigates the benefits of an asymmetric tri-stable energy harvester in low-frequency rotational motion. A theoretical model framework is presented, which considers the effect of the rotational motion, to describe the dynamic characteristics and output voltage of the harvester. More importantly, the asymmetric tri-stable energy harvester is experimentally verified to be better than the symmetric one under various rotational speeds. The former exhibits a wide working rotational speed range of 140-460 rpm. The weight component of tip mass produces a periodic harmonic exciting force due to rotational motion, which can be designed to enhance energy harvesting.