Abstract:

ESDU 06004 contains examples illustrating the application of Dwell-Rise-Fall- Dwell (DRFD) and Dwell-Fall-Rise-Dwell (DFRD) cam motions, including blended motions and those having a constant velocity component interposed between components controlling the acceleration and retardation of the follower. Motions having equal rise and fall periods are analysed in a companion Data Item ESDU 06002 and motions whose rise and fall segments are asymmetric are analysed in a further Data Item ESDU 06003. The examples are confined to the establishment of the dimensions needed to define the motion, together with the provision of curves illustrating the follower displacement, velocity, acceleration and jerk relative to the cam angle for that motion segment. The equations of Dwell-Rise-Dwell (DRD) cam laws, some of which are suitable only for the component of blended motions adjoining the dwell, are given in ESDU 82006. The use of an associated computer program, described in ESDU 06005 (to be issued), is recommended for all calculations, including sensitivity analyses, to optimise the motion. Examples 1 go 6 apply to follower motions having equal rise and fall periods, whereas Example 7 illustrates procedures for analysing an asymmetric output motion having unequal rise and fall periods.