Mechanism Design And Human-Machine Motion Space Analysis Of The Horizontal Traction Lower Limb Rehabilitation Robot

In the context of aging population in China,the number of patients with lower limb dysfunction caused by stroke is increasing rapidly.The lower limb rehabilitation robot which can efficiently provide rehabilitation training for patients has become a research hotspot.In this paper,a lower limb rehabilitation robot which can provide multi joint training for patients is proposed,and a method of measuring joint range of motion based on RGB-D camera is proposed,which provides an important basis for setting the safety training range of lower limb rehabilitation robot.First of all,this paper analyzes the structure of human lower limb,and puts forward the specific design requirements of lower limb rehabilitation robot.Then the mechanism of the lower limb rehabilitation robot is designed,which can realize the motion of the hip joint in the sagittal plane and coronal plane,the motion of the knee joint in the sagittal plane and the following motion of the ankle joint.Secondly,the forward and inverse kinematics of the lower limb rehabilitation robot is calculated,the velocity Jacobian of the mechanism is solved,and the linear path and circular path are designed for the robot.The two designed trajectories are planned to ensure their smoothness in time.In order to improve the accuracy of robot trajectory following in the operating space,a PD cross coupling controller is designed,and its superiority over PD controller is verified by simulation.Thirdly,the principle of RGB-D camera is analyzed,and the transformation relationship between camera coordinate system and pixel coordinate system is established.Then the human body and rehabilitation robot are marked,and the RGB-D camera is used for image acquisition.The threshold segmentation method and Hough transform principle are used to process the image.After that,the range of motion of hip joint,knee joint in sagittal plane and hip joint in coronal plane were obtained by analyzing the image data.Combined with the range of motion of each joint,the range of motion of the rehabilitation robot is determined.Finally,the validity of joint motion measurement method based on RGB-D camera is verified,and the prototype of lower limb rehabilitation robot is built.The electrical control system of the prototype is designed,and the software control logic of the prototype is analyzed.Combined with the prototype,the tracking experiment is carried out to verify the tracking performance of the designed rehabilitation robot.