ARRIpede: A stick-slip micro crawler/conveyor robot constructed via 2 ½D MEMS assembly
ABSTRACT Recent advances in 2frac12D and 3D hybrid microassembly using MEMS snap fasteners and die-level bonding for interconnects, makes possible the miniaturization of exciting new small robots configured for various functions, such as flying, crawling, or jumping. ARRIpede is one example of a ldquodie-sizerdquo crawling microrobot constructed by assembly and die stacking. It consists of a MEMS die ldquobodyrdquo, in-plane electrothermal actuators, vertically assembled legs, and an electronic ldquobackpackrdquo to generate the necessary gait sequence. The robot has been designed using a stick-slip simulation model for a target volume of 1.5 cm times 1.5 cm times 0.5 cm, a 3.8 g mass, and velocities up to 3 mm/s. Even though work remains to be completed in packaging the robot, we demonstrated that the robot design is sound by experimentally evaluating the leg actuation force, the payload carrying capacity, the power consumption, and the manipulation ability of an inverted ARRIpede prototype. A configuration that carries a payload approximately equal to its own weight shows excellent steering ability. A reasonable match between simulations and experiments is noted, for example, when the legs are actuated at 45 Hz and 10 V, the crawling velocity of the microrobot was experimentally measured to be 0.84 mm/s or 18.7 mum per step, while the simulated leg displacement was 18.5 mum per step. The prototyped ldquoconveyorrdquo mode had a maximum measured linear velocity in excess of 1.5 mm/s, while consuming approximately 500 mW of power. We expect that for achieving lower speeds, such as 0.15 mm/s, the power consumption can be reduced to a few mW, enabling untethered operation.
Conference Paper: A four degree of freedom microrobot with large work volume.[Show abstract] [Hide abstract]
ABSTRACT: This paper presents a unique four-axis articulated MEMS robot, constructed by microassembly, targeting micro and nano scale manipulation and probing applications. The first version of this microrobot has a 2P2R (Prismatic Prismatic Revolute Revolute) kinematic configuration, occupies a total volume of 3mm × 2mm × 1mm, and operates within a workspace envelope of 50µm × 50µm × 75µm. This is by far the largest operating envelope of any independent micropositioner with non-planar dexterity. As a result, it can be classified as a new type of dimensional miniaturized top-down assembly robot with dimensions smaller than 1 cm. The robot incorporates a combination of miniature flexures and cables to drive its joints from high force MEMS actuators. Actuation is accomplished via two banks of in-plane electrothermal actuators, one coupled through an out of plane compliant socket, and the other one coupled remotely via a 30 µm diameter Cu wire. In this paper, we decouple the motion of the robot joints by identifying the robot Jacobian, and we offer preliminary experimental characterization of the microrobot repeatability. Results show that the robot is repeatable to under 0.5 µm along XY and 0.015 degrees along pitch and yaw degrees of freedom.2009 IEEE International Conference on Robotics and Automation, ICRA 2009, Kobe, Japan, May 12-17, 2009; 01/2009
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ABSTRACT: The design of a robotic manipulator, including the type of joints, actuators, and other geometric parameters significantly affects its precision (or positioning uncertainty) at the end-effector. Furthermore, sensor and actuator resolution and choice of control scheme will also contribute to the manipulator's precision. Modeling and simulation of these uncertainties can provide useful insight and serve as design guidelines for precision manipulators used in micro and nanomanufacturing. Of particular interest are assembly scenarios where the tolerance budgets are stringent and precision requirements are high, but there is little space for extensive sensor feedback due to a small work volume. In this paper, we investigate the effect of parametric uncertainties in a serial robot chain composed of prismatic or rotary “modules” on the overall positioning uncertainty at the end-effector. Two types of errors are considered: static errors due to misalignment and link parameter uncertainties, and dynamic errors due to inaccurate motion of individual links. Using common uncertainty metrics, we compare the precision of six different robot kinematic chain configurations and select the best suited ones for a generic Peg-in-Hole microassembly task.Intelligent Robots and Systems (IROS), 2011 IEEE/RSJ International Conference on; 01/2011