Multi-material compliant mechanism design and haptic evaluation

Abstract

Compliant mechanism design has been applied to more and more areas and has attracted increasing research interest in recent years. Its relative flexibility instead of rigid joints excels in simplicity of manufacturing and assembly, as well as reduction in cost, backlash, noise, lubrication and so on. Most compliant linkages are made by sole material, resulting in thin and small joints. To improve the endurance of compliant mechanisms, multi-material design is employed. Multi-material design is developed with the advantages of improved function and appearance of a product. In TPE (thermoplastic elastomer) molding process, multi-shots or over molding provides variances in geometry and topology for multi-material combination. However, it is difficult to define the geometry and topology, and the users' preferences vary a lot, a typical design example is illustrated in this paper. Also, compliant product modelling and a real-time haptic function evaluation are presented. The intuitive experience of hatpic evaluation gives the designer or user a quick impression of the stiffness of the mechanism in order to evaluate the product function. The proposed methodology is illustrated by a case study: the redesign of a daily-used gripper and its haptic evaluation.