This paper presents an up-to-date survey of graphical tactile displays. These devices provide information through the sense of touch. At best, they should display both text and graphics (text may be considered a type of graphic). Graphs made with shapeable sheets result in bulky items awkward to store and transport; their production is expensive and time-consuming and they deteriorate quickly. Research is ongoing for a refreshable tactile display that acts as an output device for a computer or other information source and can present the information in text and graphics. The work in this field has branched into diverse areas, from physiological studies to technological aspects and challenges. Moreover, interest in these devices is now being shown by other fields such as virtual reality, minimally invasive surgery and teleoperation. It is attracting more and more people, research and money. Many proposals have been put forward, several of them succeeding in the task of presenting tactile information. However, most are research prototypes and very expensive to produce commercially. Thus the goal of an efficient low-cost tactile display for visually-impaired people has not yet been reached.

This paper reports on the development of a lightweight hyper-redundant manipulator driven by embedded dielectric polymer actuators. This manipulator uses binary actuation and belongs to a class of digital mechanisms that are able to perform precise discrete motions without the need for sensing and feedback control. The system is built from an assembly of modular parallel stages and has potential to be miniaturized for applications ranging from biomedical devices to space system components. The polymer actuators can make such devices feasible. This paper presents the design of a modular polymer actuator that can work under both tension and compression. The actuators achieve improved performance by incorporating an elastic passive element to maintain uniform force-displacement characteristic and bi-stable action. A flexible frame also insures nearly optimal pre-strain required by dielectric film based actuators.

Compliant bistable mechanisms are a class of mechanical systems that benefit from both compliance, allowing easy manufacturing on a small scale, and bistability, which provides two passive and stable positions. These properties make them first-class candidates not only for microswitches but also several other robotic appliances. This paper investigates the actuation of a simple bistable mechanism, the bistable buckled beam. It is pointed out that the position of the actuation has a significant impact on the behavior of the system. A new model is proposed and discussed, with experimental validations to compare central and offset loading, highlighting the strengths of each.