Search Results (2)

In recent years, consumer-level virtual-reality (VR) devices and content have become widely available. Notably, establishing a sense of presence is a key objective of VR and an immersive interface with haptic feedback for VR applications has long been in development. Despite the state-of-the-art force feedback research being conducted, a study on directional feedback, based on force concentration, has not yet been reported. Therefore, we developed directional force feedback (DFF), a device that generates directional sensations for virtual-reality (VR) applications via mechanical force concentrations. DFF uses the rotation of motors to concentrate force and deliver directional sensations to the user. To achieve this, we developed a novel method of force concentration for directional sensation; by considering both rotational rebound and gravity, the optimum rotational motor speeds and rotation angles were identified. Additionally, we validated the impact of DFF in a virtual environment, showing that the users’ presence and immersion within VR were higher with DFF than without. The result of the user studies demonstrated that the device significantly improves immersivity of virtual applications. Full article

We present a novel design of a single-cylinder free piston engine linear generator (FPELG) incorporating a linear motor as a rebound device. A systematic simulation model of this FPELG system was built containing a kinematic and dynamic model of the piston and mover, a magneto-electric model of the linear generator, a thermodynamic model of the single-cylinder engine, and a friction model between the piston ring and cylinder liner. Simulations were performed to understand the relationships between pre-set motor parameters and the running performance of the FPELG. From the simulation results, it was found that a motor rebound force with a parabolic profile had clear advantages over a force with a triangular profile, such as a higher running frequency and peak cylinder pressure, faster piston motion, etc. The rebound position and the amplitude of rebound force were also determined by simulations. The energy conversion characteristics of the generator were obtained from our FPELG test rig. The parameters of intake pressure, motor frequency, and load resistance were varied over certain ranges, and relationships among these three parameters were obtained. The electricity-generating characteristic parameters include output power and system efficiency, which can measure the quality of matching the controllable parameters. The output power can reach 25.9 W and the system efficiency can reach 13.7%. The results in terms of matching parameters and electricity-generating characteristics should be useful to future research in adapting these engines to various operating modes. Full article