Research On Kinematic Control Of 3-RRRU Parallel Manipulator

This dissertation deals with kinematic control of a 3-RRRU parallel manipulator with three translational degrees of freedom, and the main contents are as follows:Firstly, the inverse kinematics problems, including inverse position and angular velocity solutions, is achieved by solving inverse kinematic equations of the 3-RRRU parallel manipulator with the help of D-H matrix and geometric vector method respectively. Each of limbs has 4 inverse solutions at most and thereby the manipulator has 64 inverse solutions at most.Secondly, a study is carried out to detail the hardware architecture of an eight-axis PMAC-PC motion control card and a dual-ported RAM card. It is explained the function of hardware units and operating principles of both cards. An analysis is made of the communication methods between the host and either of them. Also discussed is the operating mechanism between the dual-ported RAM and PMAC-PC.Thirdly, a kind of two-step interpolation strategy is proposed in operation space and joint space and an exponential acceleration and deceleration algorithm is introduced to the former motion acceleration and deceleration planning period, which is the base of four sorts of smooth transfer models for continuous segment trajectory.Finally, the motion control system of the 3-RRRU parallel manipulator is developed on the basis of hardware platform of"IPC+PMAC"architecture and software platform of Windows 2000 Operating System. A real time communication mechanism is established between them and every task in a multitask operation of the system is divided into a functional module. Then the basic control functions of the system can be realized by adopting the schedule mechanisms of the multitask operation.