Developing kinesthetic haptic devices with advanced haptic rendering capabilities is challenging due to the limitations on driving mechanisms. In this study, we introduce a novel soft electrohydraulic actuator and develop a kinesthetic haptic device utilizing it as the driving unit. We established a mathematical model and conducted testing experiments to demonstrate the device's ability to stably output controllable feedback force. Our experiments also demonstrates that this device exhibits fast response characteristics. By utilizing the easily controllable nature of the soft electrohydraulic actuator, we were able to achieve high-resolution controllable feedback force output. Furthermore, by modulating the waveform of the driving high voltage, the device acquired the capability to render variable frequency haptic vibration without adding any extra vibration actuator. Using this kinesthetic haptic device, we built a teleoperated robotic system, showcasing the device's potential application as a haptic force feedback system in the field of robotics.

Haptic feedback can improve safety of teleoperated robots when situational awareness is limited or operators are inattentive. Standard potential field approaches increase haptic resistance as an obstacle is approached, which is desirable when the operator is unaware of the obstacle but undesirable when the movement is intentional, such as when the operator wishes to inspect or manipulate an object. This paper presents a novel haptic teleoperation framework that estimates the operator's attentiveness to dampen haptic feedback for intentional movement. A biologically-inspired attention model is developed based on computational working memory theories to integrate visual saliency estimation with spatial mapping. This model generates an attentiveness map in real-time, and the haptic rendering system generates lower haptic forces for obstacles that the operator is estimated to be aware of. Experimental results in simulation show that the proposed framework outperforms haptic teleoperation without attentiveness estimation in terms of task performance, robot safety, and user experience.