Research On The Modular Manipulator For The Handicapped And The Elderly

With the growing problem of global aging and the increasing numbers of thedisabled, more and more aged and disabled people not only cause tremendousburden on their families but also put an enormous stress on national health andsocial security system. For another thing, the robotics has seen a rapid developmentunder the impetus of the science and technology, the robot gradually penetrates intoareas of family life and service from the traditional industry, as a result, the structureof the robot changes from one user, one redesign to the direction ofstandardization and modularization. Combined with the National High-TechnologyProject (863) in key technology of modular robot, this thesis develops a modularmanipulator system which can be installed in intelligent wheelchairs aimed atassisting the aged or disabled to complete daily activities, such as fetchingsomething or opening doors.Firstly, this paper develops a modular manipulator. A rotary joint modulecharacterized with compact module structure, light weight and large output torque isdesigned, which has a standard mechanical and electrical interface and mainlyconsists of driving, controlling and communication modules. The motor, encoderand brake in the joint are arranged parallel to each other. The manipulators withdifferent DOF and configurations can be assembled according to the user sdemand benefiting from their standard mechanical and electrical interface.Secondly, the modularization kinematics of the modular manipulators isanalyzed. Based on unified mathematical expressions of various modules,kinematics models of manipulators with different configurations are gained. Usingthe configuration plane matching method, spatial configuration of the manipulator istransformed into plane geometry relation and inverse kinematics problem of themanipulators is solved through the matching of position and posture. Besides, amanipulator kinematics simulation platform is designed to verify the correctness ofthe modular kinematics algorithm with the example of a6-DOF manipulator. TheJacobian matrix and the workspace of the manipulator is derived and analyzedrespectively, which lay a foundation for manipulator controlling.Thirdly, the modular manipulator control system based on Industrial Ethernetand CAN bus is established, which consists of an upper computer, a controller andseveral drivers etc. A man-machine interactive platform which can realize operationcommand interaction between operators and manipulators as well as virtualenvironment simulation is developed. Motion control of the manipulator is conducted through path planning and kinematics solution. Communication betweendifferent control layers is realized by establishing the communication protocol. Thecontrol system can adapt to manipulators with various configurations benefitingfrom the modular structure of the manipulator.Finally, research on the control strategy and prototype experiment is carried out.Using inner speed loop and outer position loop to realize trajectory control of themanipulator. The experiments of straight line and curved line trajectory trackingmeet the control requirements. An impedance controller is designed for the action ofpulling drawer, which can realize force control based on position loop. Simulationof the impedance parameters and experiment are carried out, which validated thatthe proposed compliance control method is effective. Using a laser tracker toachieve calibration and compensation for the kinematics parameters of themanipulator, the positional accuracy of the manipulator is tested as well; the resultsmeet the design requirements. An experiment in which the manipulator pours waterand assists people to drink is designed to verify its operation ability.