Motion Control of 3-DOF Under-actuated Cable-truss Robotic Hand

Abstract

：The cable-truss robotic hand is a novel type of under-actuated hand that is proposed by tendon-pulley transmission and parallel four-linkage mechanism. The joint movements are driven by cable driving force simultaneously and coupled with each other, and which directly changes the distribution of cable driving force in each phalange. Therefore, the cable-truss underactuated system has the characteristics of strong nonlinearity and motion coupling. Then, the finger driven by the TP transmission is translated to the equivalent joint driven mechanism, and a quasi-static kinematic model of a 3-DOF finger is established. On the basis of the constraints of maximum movement space of the finger, the distributions of joint springs are determined and the finger quasi-static movement space is analyzed. The general dynamic equation of the finger is established by using Lagrange's method, and the equivalent dynamic model in "A-P" form is obtained. On the basis of "A-P" dynamic model, research on motion control in the pre-bending stage is carried out. The effectiveness of the proposed analysis method and motion control strategy is verified by simulation analysis and prototype experiment.

Reliability Evaluation for Cable-Spring Folding Wing Considering Synchronization of Deployable Mechanism

“…Nevertheless, the reliability index of folding wing only concerns the deployment time, ignoring the asynchronous problem caused by the deployment time difference. Therefore, in view of the synchronization reliability problem, Yu et al proposed a novel synchronization reliability evaluation method by dividing the integral domain into several independent domains, which can more accurately evaluate the reliability of folding wings [19]. However, the structural details and loading condition of deployable mechanism were neglected; instead, an agent model was used in this approach.…”

“…Moreover, there is little publicly available literature on rigid-flexible coupling deployable mechanisms of folding wing, and these are not only old but also do not offer a detailed analysis. The cable-spring deployable mechanism of folding wing is a novel type of rigid-flexible coupling structure, using a wheel-rope transmission system and a parallel spring driving mechanism [19]. The application is related to national defense and security, and has the characteristics of simple structure, flexible controllability and high reliability.…”