| Recently, because of stroke sequelae and the lesions of spinal cord, muscles, nervesand brain, as well as natural and man-made disasters, the number of the patients disabled inthe hand increases year by year. In order to solve the diet care problem of the patients withhand disability, the research on meal-assistance robot has been done in the paper. On onehand, the robot enhances the self-confidence of the disabled to have meal on their own; onthe other hand, it can reduce the workload of the nursing staff and liberate the socialproductive forces. And it has great practical significance for improving the independentdining level of the disabled and promoting social harmony and progress.With the funding of the National SME Innovation Fund (08C26212301760) andHarbin Innovation Fund (2009RFKXG009), in order to develop a meal assistance robotwhich is practical, smart, safe, simple and flexible, theoretical analysis and experimentalresearch of the meal assistance robot, in terms of the mechanical structure, man-machineinteractive mode, motion planning, dynamics analysis, control strategies and the visualsystem, have been carried out deeply.Through the symptoms analysis of the application objects of meal assistance robot, andaccording to the needs of patients with different degree of disability, a kind of mealassistance robot was designed in the paper, which consists of a rotary table and amanipulator with spoon-chopsticks style tableware. A general research on the robot’smechanical structure, control scheme and man-machine interactive mode has been done.Kinematic analysis, path planning and work space analysis of the robot have been donein the paper, and then the link parameters of the robot and the position and orientationparameters of the robot’s spoon at each track identification point have been decided. Theplate zoning design of the robot has been done, so that the food in four dishes is planned tothree different locations of the meal assistance manipulator. The motion planning in whichthe curves of velocity are smooth has been done, which lays the foundation for the controlstudy of the robot.The dynamic model of the robot has been established based on Lagrange equations,and the dynamics analysis of the robot has been carried out using MATLAB software. Theoctahedral food model based on spherical rigid body constrained by spring-damper wasestablished using ADAMS software. Dynamics characteristics analysis and scoopingefficiency issues of spoon-chopsticks style tableware and a common spoon are analyzed,which verifies that spoon-chopsticks style tableware is better in getting food. In order to improve control accuracy, in addition to the conventional PID control, the fuzzy self-tuningPID control of the entire meal assistance task was carried out. In the meal assistance sectionof contacting environment operations, the study of impedance control was carried out andthe impedance parameter adjustment law was deduced. By adjusting the impedancecontroller parameters, meal assistance robot can meet specific flexibility. So the robot canavoid damage, as well as the plates and meal, through the process of taking meal.The visual system research of the robot, including food recognition system and headidentify system has been done. Food recognition system imitates the human visual systemto identify the distribution of food in the plates, and then transmits the information into thehost computer, so as to control the robot to accomplish the meal assistance task. Headidentify visual system can collect the information of head movement, which is thehuman-computer interaction of aphasia patients with severe limb disabilities.The robot prototypes is developed, and the trajectory tracking experiment is studied bydSPACE semi-physical simulation experimental platform. The reasonableness of the robotmechanical structure and the feasibility of the control strategy are verified. Thus, the mealassistance robot studied in the paper can achieve the diet care of the disabled in the hand. |
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