基于独立运动分流标记法的多环耦合机构自由度分析方法

Method of Mobility Calculation for a Coupled Mechanism Based on Independent Motion Shunting Measurement

基于运动分流法,提出一种改进的多环耦合机构的自由度分析方法,可将复杂的多环耦合机构拆分成多个运动独立的链.应用螺旋理论分析独立运动链所含耦合节点相对于机架的独立运动,并用广义运动副等效代替,整个机构就可以等效为一个并联机构.通过分析等效并联机构的运动和约束螺旋系,即可确定多环耦合机构动平台的自由度数目和性质.将提出的方法应用于一种Hoberman Switch-Pitch魔球机构的自由度分析,验证了该方法的有效性及简单性.

An improved method based on screw theory for constraint and mobility analysis of complex coupled multi-loop mechanisms is proposed. The innovation is the proposition of motion shunting measure,by which the complex multi-loop coupled mechanisms can be split into several independent elements. The relative motion of the coupled-nod link in each element was analyzed and replaced by a generalized kinematic chain. The coupled mechanism was ultimately regarded as a common parallel mechanism. Limb twist systems and limb constraint systems of the equivalent parallel mechanism were analyzed and the characteristic of the output mobility was identified. With the proposed method,a typical Hoberman Switch-Pitch ball was analyzed,which shows the validity and simplification of the new method.