A 6-DOF Gait Rehabilitation Robot With Upper and Lower Limb Connections That Allows Walking Velocity Updates on Various Terrains

This paper presents a 6-DOF gait rehabilitation robot that allows patients to update their walking velocity on various terrain types and navigate in virtual environments (VEs) through upper and lower limb connections. This robot is composed of an upper limb device, a sliding device, two footpad devices, and a body support system. The footpad device on the sliding device generates 3-DOF spatial motions on the sagittal plane for each foot. This allows the generation of various terrain types for diverse walking training. The upper limb device allows users to swing their arms naturally through the use of a simple pendulum link with a passive prismatic joint. Synchronized gait patterns for this robot are designed to represent a normal gait with upper and lower limb connections. To permit patients to walk at will, this robot allows walking velocity updates for various terrain types by estimating the interaction torques between the human and the upper limb device, and synchronizing the lower limb device with the upper limb device. In addition, the patient is able to navigate in VEs by generating turning commands with switches located in the handles of the upper limb device. Experimental results using a healthy subject show that the user can update the walking velocity on level ground, slopes, and stairs through upper and lower limb connections. In addition, the user could navigate in the VEs with walking velocity updates and turning input command allowing various rehabilitation training modes. During a pilot clinical test, a hemiplegic patient could use the suggested gait rehabilitation robot with a slow walking speed. The rehabilitation plan was also suggested for the patient and the possible therapeutic effects of the suggested rehabilitation robot system are discussed.