In this paper a polymer sensorised microgripping tool for micromanipulation is presented. The gripper structure is made by moulding of polyurethane in silicon moulds by the technique of shape deposition manufacturing (SDM), in which the force sensing elements and part of the actuator (in this case, microstrain gauges and SMA (shape memory alloy) wire, respectively) are embedded into the microgripper in one process step. The actuation principle for the microgripper is an SMA wire. The advantages of the fabrication process are low cost and manufacture cycle time. This paper details the technique for fabrication of the microgripper to produce prototypes. These prototypes were then tested and characterised in terms of force output, hysteresis and repeatability. A further miniaturised unsensorised microgripper based on the same actuation principle and fabrication process (but less than half the size) was fabricated to demonstrate the possibility of further downscaling.

Remote manipulation tasks in the small scale can often not be performed autonomously, due to the unstructured nature of the environments and the limited capabilities of sensor and localization technologies. For these tasks, teleoperated systems are used, in which the human operator is integral part of the control. In time-delayed teleoperation, the operator gradually adopts discrete control strategies, such as 'move-and-wait'. In this paper, we present and compare three different control strategies for driving a nanomanipulation system with direct vision feedback. Two strategies are based on a fixed step size to move the manipulator, while the third uses a variable step size. The strategies are compared on a 2D fine positioning task. Experimental results are in agreement with Fitts' law and show that the third strategy, besides allowing movements of size ranging across several orders of magnitude, also allows to complete the fine positioning task in less time. The control strategies can be used in general to control vision-guided teleoperation systems affected by time delay.