A. J. McDaid 1 e-mail: amcd039@aucklanduni.ac.nz E. Haemmerle S. Q. Xie K. C. Aw Department of Mechanical Engineering, The University of Auckland, Private Bag 92019, Auckland, 1010, New Zealand Design, Analysis, and Control of a Novel Safe Cell Micromanipulation System With IPMC Actuators This paper presents the design, analysis, and control of a novel micromanipulation sys- tem to facilitate the safe handling/probing of biological cells. The robotic manipulator has a modular design, where each module provides two degrees-of-freedom (2DOF) and the overall system can be made up of a number of modules depending on the desired level of dexterity. The module design has been optimized in simulation using an integrated ionic polymer-metal composite (IPMC) model and mechanical mechanism model to ensure the best system performance from the available IPMC material. The optimal sys- tem consists of two modules with each DOF actuated by a 27.5 mm long by 10 mm wide actuator. A 1DOF control structure has been developed, which is adaptively tuned using a model-free iterative feedback tuning (IFT) algorithm to adjust the controller parame- ters to optimize the system tracking performance. Experimental results are presented which show the tuning of the system improves the performance by 24% and 64% for the horizontal and vertical motion, respectively. Experimental characterization has also been undertaken to show the system can accurately achieve outputs of up to 7 deg and results for position tracking in both axes are also presented. [DOI: 10.1115/1.4024226] Keywords: ionic polymer-metal composites (IPMC), micromanipulation, iterative feedback tuning (IFT), design, control, actuator 1 Introduction Rapid advances in the bioscience and medical fields rely heav- ily on the availability of state-of-the-art tools and equipment to facilitate the scientific research. In these fields, the demand for manipulation of biological materials at the microscale and nano- scale is becoming huge for applications such as DNA injection and single cell cloning [1]. This research has the potential to have a large impact on a variety of diseases such as cancer, diabetes, and neuro-degeneration as well as diseases of the cardiovascular system, lungs, blood, and skeleton. As this research advances more emphasis is being placed on single cell manipulation, which demands manipulation systems that are more accurate and dexter- ous as well as safer, causing less damage to the cells themselves. In order to facilitate this scientific research, novel intelligent microdevice and nanodevice must be designed, which are capable of operating in biological environments for safe cell handling and manipulation [1–3]. Current techniques of cell manipulation commonly damage cell walls and membranes making them inadequate for many tasks involving “soft” biological materials like human cells, for exam- ple heating when using laser trapping or the rigidity and lack of force compliance of piezo-grippers, microtweezers, and stiff mechanical stages [1,2]. This has a major effect on the progres- sion of scientific knowledge resulting in significant loss of research time, money, and resources in addition to raising ethical issues [3]. IPMCs have intrinsic properties which make them desirable sensors and actuators for micromanipulation, including very low mass, custom geometries, scalability for miniaturization, ability to operate in cellular environments, flexibility and compliance, low power consumption and the ability to accurately achieve both microdeflection and macrodeflection without any gearing or other complex mechanisms [4,5]. IPMCs present a unique and smart system for cell manipulation due to their ability to work well in fluid and cellular environments as well as their natural compliance giving them a “soft touch” when interacting with sensitive materi- als and/or in sensitive environments. Unfortunately, IPMCs also have some disadvantages, including low blocking force, dehydra- tion (or electrolysis when operating in water), back relaxation, and poor repeatability and as such clever mechanical design and advanced control schemes must be developed to overcome these issues. Employing IPMC actuators as cell and micro-organism manipulators will present a unique solution for safe handling and manipulation of biological cells through their inherent compliance coupled with precise control. IPMCs produce a bending deformation when a voltage is applied across them in a cantilever configuration (as depicted in Fig. 1), and conversely produce an electrical potential when they are deformed. IPMC material is made up of a perfluorinated ionic membrane sandwiched between two thin metal electrodes, typi- cally Au or Pt. When a voltage bias is applied across the material the hydrated mobile cations are attracted to cathode which causes an accumulation of mass, and hence a swelling on one side of the IPMC and a resulting bending actuation. The opposite effect causes the sensing phenomena, although the sensing voltage is typically 1–2 orders of magnitude smaller than that required for actuation. Because of IPMCs inherent compliance and the recent advances in IPMC control, IPMCs are showing major promise as cell manipulators with the unique ability to act as a precise and reli- able manipulation system which is superior to current devices [1,7,8]. IPMCs have previously shown promise for other biomedical applications including active catheters, an artificial heart 1 Corresponding author. Contributed by the Design Innovation and Devices of ASME for publication in the JOURNAL OF MECHANICAL DESIGN. Manuscript received February 8, 2012; final manuscript received March 27, 2013; published online May 9, 2013. Assoc. Editor: Diann Brei. Journal of Mechanical Design JUNE 2013, Vol. 135 / 061003-1 Copyright V C 2013 by ASME Downloaded From: http://mechanicaldesign.asmedigitalcollection.asme.org/ on 06/03/2013 Terms of Use: http://asme.org/terms