Load-flow based design of compliant mechanisms with embedded soft actuators

Transmission members such as gears and linkages are ubiquitously used in mechatronic systems to tailor the performance of actuators. However, in most bio-inspired soft systems the actuation and transmission members are closely integrated, and sometimes indistinguishable. Embedded actuation is greatly advantageous for attaining high stroke and transferring large output forces. This paper attempts at a systematic synthesis of compliant systems with embedded contractile actuators and passive members to achieve a particular kinematic objective. The paper builds on recent understanding of a compliant mechanism topology where the constituent members can be functionally classified as load transferring transmitters and strain energy storing constraints. The functional equivalence between the transmitter members and actuators are used to replace transmitters in tension with contractile actuators, thus realizing a compliant embedded system. Once a single-input single-output compliant mechanism is designed, and its load flow behavior mapped, systematic guidelines and best practices are established for embedding actuators within the topology to increase performance without altering the kinematic behavior. Several examples, including a prototype that used soft pneumatic artificial muscles is presented to validate the synthesis framework. The initial results will form the basis for designing fully autonomous compliant systems with embedded actuators and sensors without the use of computationally expensive techniques.