LECTURE4-12(9.26)课件.ppt

Review The tasks of kinematic analysis of mechanisms? to find angular positions, angular velocities and angular accelerations of driven links and/or positions , linear velocities and linear accelerations on driven links, according to input parameters of driving link(s) and the dimensions of all links. Methods of kinematic analysis of mechanisms? (1)Graphical method (2)Analytical method Assur group method * (3)Experimental method The procedures of the kinematic analysis in multi-bar linkage mechanism by Assur-group method? (1) dividing the mechanism into Assur groups. Some commonly used kinematic analysis subroutines? The LINK subroutine The RRR subroutine The RPR subroutine Main program The emphasis contents: Characteristics of planar linkage mechanisms The basic form of four-bar mechanism (3)Variation of revolute four-bar mechanisms (4)Conditions for having a crank of four-bar mechanism (5)Kinematic and dynamic Characteristics of four-bar mechanism (pressure angle /transmission angle /toggle position /dead-point/quick return Characteristics ) A planar four-bar(杆) mechanism is the simplest planar linkage mechanism with one degree of freedom. 4.2 The Types of Four-bar Mechanisms In a revolute four-bar mechanism, the links connected to the frame are called side links(连架杆). Usually, one of the side links is an input link, and the other side link is an output link. In a revolute four-bar mechanism, the links connected to the frame are called side links(连架杆). Usually, one of the side links is an input link, and the other side link is an output link. If a side link can rotate continuously(连续地) through 360o relative to the frame, it is called a crank(曲柄); otherwise, a rocker(摇杆). Crank-rocker mechanism(曲柄摇杆机构):  AB is a crank while DC is a rocker. This mechanism is called a crank-rocker mechanism. Applications of crank-rocker mechanism: Applications of crank-rocker mechanism: Applications of crank-rocker mechanism: Applica