Improving user comfort in haptic virtual environments through gravity compensation

Our experience with a Haptic Workstation/spl trade/ has shown that this device is uncomfortable to use during long sessions. The main reason is the uncomfortable posture of the arms, which must be kept outstretched horizontally while supporting the weight of an exoskeleton. We describe Zero-G, a real-time weight compensation system aimed at improving user comfort by compensating for the weight of both the exoskeleton and arms (zero gravity illusion). We present experimental results complemented with electro myography measures (EMG) as an indicator of muscular activity/fatigue. Our tests show how Zero-G exerts a positive influence on the reduction of muscular fatigue when using a Haptic Workstation/spl trade/.