Research On Mechanism Optimization Design Of A Transfer Robot For Nursing Care

With the aggravation of the aging population and the increasing demand for the nursing staff,in order to improve the current situation of the shortage of nursing professionals,developing a new type of nursing robot to assist or replace the nursing staff to complete the nursing task has become the urgent need of society.In this paper,a transfer robot for nursing care is developed,which can safely and comfortably carry,move and transfer the aged people,and provide transfer and mobility services for the elders with lower extremity disability or power degradation.In this paper,the robot motion planning,workspace analysis,structure design,motion simulation and experimental verification are studied.(1)In this paper,the back carrying motion mechanism of human is studied,and the motion colletion experiment is carried out by using optical motion capture method.The "Vicon" motion capture software is used to obtain the action characteristics of the carrying motion.Based on the experimental data,the trajectory of the back carrying motion is planned,and the angle of the motion is analyzed by using the gravity method.The suitable angle is chosen to ensure the comfort of the carrying process.According to the results of the analysis,the working mode of the mechanism is determined.(2)The configuration of the robot is studied,and the advantages and disadvantages of all kinds of robot structures are analyzed and compared.Combined with the specific working process of nursing robot,the multi-joint tandem robot is selected as the mechanism configuration in this paper.Based on the idea of modularization,the primary design of each component is carried out,and the main mechanism parameters are determined.Based on the mechanism design diagram,the kinematics analysis of the mechanism is carried out by using D-H parameter method,and the relationship between the electric cylinder driving motion and the workspace is established.The Monte Carlo method is used to solve the workspace.(3)Analysing the workspace of the robot.Because of the different body parameters,the most significant difference is the difference of height,it should be ensured that the robot can carry the objects of different height on the back.On the premise of satisfying the required workspace,the length of the robot arm rod is optimized to make the mechanism more compact.Based on the optimization results,the mechanism is designed in detail and finite element analysis is carried out to ensure its reliability.On the premise of satisfying the workspace and aiming at the concrete structure,the robot trajectory is adjusted to make the working process more stable.(4)The kane method is selected to analyse the dynamics of the mechanism,the dynamic equation is derived,and the relationship between the driving force and the external load is established,which provides the basis for the dynamic performance analysis and dynamic simulation.By using ADAMS software to simulate the mechanism and simulating the actual working process in planned working mode,the kinematic parameters of the end of the mechanism,the driving force of the electric cylinder and the change of the force at the hinge of the mechanism can be obtained.These parameters provide a theoretical basis for the manufacture and commissioning of the physical prototype.Based on the simulation results,the prototype is made and tested to verify the rationality of the mechanism design and motion planning.