Ungrounded haptic rendering device for torque simulation in virtual tennis

We present an ungrounded haptic device to render a variety of tennis ball impact accelerations and torques in an interactive virtual tennis system. Impact forces are common in real life, particularly in sports. Our daily experiences shows that our sensory system can discern the variations in these resulting strong vibrations. Common eccentric mass vibration motor-based haptics cannot create the magnitudes of the force and torque, or the variations in frequencies and waveforms, or the immediacy of such impacts[Yao and Hayward 2010]. Our device overcomes the above deficiencies and increases the richness of user experience in virtual reality.