Constrained RPR Chains

Constrained RPR Chains _ Mark Plecnik

Six-bar mechanisms that include a prismatic joint can be synthesized as constrained RPR chains. These single degree of freedom constrained RPR chains are capable of reaching five task positions. The synthesis process begins by first specifying a serial, open, 3 DOF chain. The inverse kinematics are solved to find five positions of the RPR that […]

Synthesis of Six-bars

synthesis of six bars

The six-bar linkage is the next simplest 1-DOF planar mechanism after the four-bar. However, designing these mechanisms presents a challenging set of synthesis equations. For example, a four-bar motion generator is determined by a polynomial system that has 4 isolated roots (of which one is the origin), where each root represents a potential design. On […]

Rotary Weaver

rotary weaver mark plecnik

A hydraulic hose manufacturer in the US approached UC Irvine in order to design a linkage for their rotary weaver equipment. They were trying to equip their machines so that they could change out the current 2 over 2 braid pattern into a 3 over 3 braid pattern. They wanted to avoid the use of […]

Wing Mechanism

wing mechanism mark plecnik asme award

A wing mechanism was designed to reproduce a complex accelerative flapping gait from a single constant RPM motor. The flapping gate was deciphered from data obtained by Tobalske and Dial, 1996, of black-billed magpies. The synthesis process begins by specifying a 4R spatial serial chain that resembles a magpie’s anatomy. Moving the spatial chain through […]