A VR navigation of a 6-DOF gait rehabilitation robot with upper and lower limbs connections

This paper explains a 6-DOF gait rehabilitation robot, which may allow a patient to navigate in virtual reality (VR) by upper and lower limbs interactions. The suggested robot is composed of an upper limb device, a sliding device, two footpad devices, and a partial body support system. The footpad device on the sliding device will generate 3-DOF spatial motions on sagittal plane for each foot. The upper limb device will allow arm of a user to swing naturally with a simple pendulum link with a passive prismatic joint. It is possible to use this robot inside normal home for the purpose of telerehabilitation since its size is compact and its power consumption is small. Synchronized gait patterns for this robot are designed to represent natural gait with the upper and lower limbs connections. In gait rehabilitation robots, one of the important concerns is not only to follow the robot motions passively, but also to allow the patient to walk by his/her intention. Thus, this robot allows automatic walking velocity update by estimating interaction torques between the human and the upper limb device, and synchronizing the upper limb device to the lower limb device. In addition, the upper limb device acts as user-friendly input device for navigating in virtual reality. By pushing the switches located at the right and left handles of the upper limb device, a patient is able to do turning motions during navigation in virtual reality. Through experimental results of a healthy subject, we showed that rehabilitation training can be more effectively combined to virtual environments with upper and lower limb connections, which will allow various rehabilitation training modes.