Development of an ionic polymer-metal composite stepper motor using a novel actuator model

A novel ionic polymer–metal composite(IPMC)actuated stepper motor was developed in order to demonstrate an innovative design process for complete IPMC systems.The motor was developed by utilizing a novel model for IPMC actuators integrated with the complete mechanical model of the motor.The dynamic,nonlinear IPMC model can accurately predict the displacement and force actuation in air for a large range of input voltages as well as accounting for interactions with mechanical systems and external loads.By integrating this geometrically scalable IPMC model with a mechanical model of the motor mechanism an appropriate size IPMC strip has been chosen to achieve the required motor specifications.The entire integrated system has been simulated and its performance verified.The system has been built and the experimental results validated to show that the motor works as simulated and can indeed achieve continuous 360
rotation,similar to conventional motors.This has proven that the model is an indispensable design tool for integrated IPMC actuators into real systems.This newly developed system has demonstrated the complete design process for smart material actuator systems,representing a large step forward and aiding in the progression of IPMCs towards wide acceptance as replacements for traditional actuators.

A compliant surgical robotic instrument with integrated IPMC sensing and actuation

Robotic assisted surgery is becoming widely adopted by surgeons for a number of reasons,which include improved instrumentation control and dexterity as well as faster patient recovery times and cosmetic advantages.Robotic assisted surgery is currently one of the fastest growing applications in robotics.Although the traditional robotic actuators which are currently used have advanced performance which can,in some aspects,surpass that of humans,they simply do not have the capabilities and diversity required to meet the demand for new applications in robotic surgery.Novel transducers which have advanced capabilities and which allow safe operation in delicate environments are needed.Ionic polymer-metal composites(IPMCs)have extensive desirable characteristics when compared with traditional actuators and as their transduction mechanisms can mimic biological muscle they have much potential for future advanced biomedical and surgical robotics.In this research,a complete two degree-of-freedom(2DOF)surgical robotic instrument has been developed,which with the attachment of surgical tools(scalpel,etc.)has the ability to undertake surgical procedures.The system integrates an IPMC sensor and actuator at each joint.A gain scheduled(GS)controller,which is tuned with an iterative feedback tuning(IFT)algorithm,has been developed to ensure an accurate and adaptive response.The main advantages of this device over traditional devices are the improved safety through a natural compliance of the joints as well as the mechanical simplicity which ensures ease of miniaturisation for minimally invasive surgery(MIS).The components of the system have been tested and shown to have the capabilities required to operate the device for certain surgical procedures,specifically a device work envelope of 1600 mm^(2),compliance of 0.0668 m/N while still maintaining enough force to cut tissue,IPMC sensor accuracy between 3-22%and a control system which has shown to guarantee zero steady state error.