John W. Suh

Telecubes: mechanical design of a module for self-reconfigurable robotics

A Telecube is a cubic module that has six prismatic degrees of freedom whose sides can expand more than twice its original length and has the ability to magnetically (de)attach to other modules. Many of these modules can be connected together to form a modular self-reconfigurable robot. The paper presents the intended functions, discusses the physical requirements of the modules and describes two key mechanical components: a compact telescoping linear actuator and a switching permanent magnet device.

CMOS integrated ciliary actuator array as a general-purpose micromanipulation tool for small objects

The first micromachined bimorph organic ciliary array with on-chip CMOS circuitry is presented. This ciliary array is composed of an 8/spl times/8 array of cells each having four orthogonally oriented actuators in an overall die size of 9.4/spl times/9.4 mm. The polyimide-based actuators were fabricated directly above the selection and drive circuitry, Selection and activation of actuators in this array shows that integration was successful. The array was programmed to do simple linear and diagonal translations and squeeze-, centering-, and rotating-field manipulations. All three tasks were demonstrated using silicon pieces of various shapes and either 0.55 mm or 0.10 mm thick.

A complete, local and parallel reconfiguration algorithm for cube style modular robots

We present a complete, local, and parallel reconfiguration algorithm for metamorphic robots made up of Telecubes, six degree of freedom cube shaped modules currently being developed at PARC. We show that by using 2 /spl times/ 2 /spl times/ 2 meta-modules we can achieve completeness of reconfiguration space using only local rules. Furthermore, this reconfiguration can be done in place and massively in parallel with many simultaneous module movements. Finally we present a loose quadratic upper bound on the total number of module movements required by the algorithm.

Computational methods for design and control of MEMS micromanipulator arrays

As improvements in fabrication technology for microelectromechanical systems, or MEMS, increase the availability and diversity of these micromachines, engineers are defining a growing number of tasks to which they can be put. The idea of carrying out tasks using large coordinated groups of MEMS units motivates the development of automated, algorithmic methods for designing and controlling these groups of devices. We report on progress towards computational MEMS, taking on the challenge of design and control of massively parallel arrays of microactuators. Arrays of MEMS devices can move and position tiny parts, such as integrated circuit chips, in flexible and predictable ways by oscillatory or ciliary action. The theory of programmable force fields can model this action, leading to algorithms for various types of micromanipulation that require no sensing of where the part is. Experiments support the theory.

Organic thermal and electrostatic ciliary microactuator array for object manipulation

Abstract An organic thin-film ciliary microactuator array using independent thermal and electrostatic actuation is described. A polyimide thermal bimorph structure provides for large angle deflection with high load capacity. Electrostatic electrodes provide low-power hold-down, capacitive sensing, and feedback control capabilities. Integrating four orthogonally oriented actuators into a unit cell and replicating this cell into an array allows for precise movement of small objects in arbitrary directions. The ciliary microactuator array has immediate applications for positioning, alignment, inspection, and assembly of small parts, such as IC dice, with micron-scale resolution.

On the general reconfiguration problem for expanding cube style modular robots

We discuss the theoretical limitations for reconfiguration of metamorphic robots made up of Telecubes, six degree of freedom cube shaped modules currently being developed at Xerox PARC. We show that by using meta-modules composed of 8 individual modules as a backbone for building the desired shape, we can establish completeness for the reconfiguration as well as time and space bounds for the process. Finally we present several open problems in the field of reconfiguration.

Thermally Actuated Omnidirectional Walking Microrobot

We describe a walking microrobot that is propelled by cilialike thermal bimorph actuator arrays. The robot consists of two actuator array chips, each having an 8 × 8 array of “motion pixels,” which are composed of four orthogonally oriented cilia. Each group of unidirectional cilia is controlled independently for each chip, which provides planar motion with three degrees of freedom (x, y, θ). The robot is approximately 3 cm in length, 1 cm in width, and 0.9 mm in height and has a mass of 0.5 g. By varying the actuation frequency and motion gait strategy, the direction and velocity of the motion can be controlled. In this paper, we present the system architecture, control mechanism, and modeling of the robot, as well as experimental results, during linear and rotary motion. The robot can carry loads up to seven times its own mass, and it can operate at speeds up to 250 μm/s with step sizes from 1 to 4 μm.

Fully programmable MEMS ciliary actuator arrays for micromanipulation tasks

The first micromachined bimorph organic ciliary array with on-chip CMOS circuitry is presented. This device is composed of an 8/spl times/8 array of cells each having four orthogonally oriented actuators in on overall die-size of 9.4 mm/spl times/9.4 mm. The polyimide based actuators were fabricated directly above the selection and drive circuitry. Selection and activation of actuators in this array shows that integration was successful. The integration of CMOS electronics and MEMS micromechanisms allows the implementation of new task-level micromanipulation strategies. New low-level control algorithms (actuator gaits) were also demonstrated. The array was programmed to perform several kinds of manipulation tasks, including linear translation, diagonal motion, as well as vector field operations such as squeeze field and radial field orienting and centering. Preliminary experiments were also performed using thin silicon dice of about 3 mm/spl times/3 mm/spl times/0.5 mm size as the object being moved.

Vector fields for task-level distributed manipulation: experiments with organic micro actuator arrays

Distributed manipulation experiments were performed using a massively-parallel, microfabricated actuator array. An organic ciliary array of thin-film polyimide bimorph microactuators exploiting combined thermal and electrostatic control was employed to implement task-level, sensorless manipulation strategies for macroscopic objects. The tasks of parts-translation, -rotation, -orientation, and -centering were demonstrated using small integrated circuit (IC) dice. Strategies were programmed in a fine-grained SIMD (single instruction, multiple data) fashion by specifying planar force vector fields. When a part is placed on the array, the programmed vector field induces a force and moment upon it. The parts equilibrium states may be predicted and cascaded (using a sequence of fields) to bring the part to a desired final state. Vector fields with and without potential were tested in experiments, and the behavior of parts in the fields was compared with the theory of programmable vector fields. These fields were implemented by actuating the organic cilia in a cyclic, gait-like fashion. Motion in non-principal (e.g. diagonal) directions was effected by a pairwise coupling of the cilia to implement virtual cilia. These experiments suggest that MEMS actuator arrays are useful for parts-orientation, -posing, -transfer, -singulation, and -sorting.

Ciliary microactuator array for scanning electron microscope positioning stage

The performance of a ciliary microactuator array as a positioning stage inside a scanning electron microscope is described. Such arrays are attractive because they can provide micron scale positioning resolution with direct electronic control within the sample chamber. The present array uses thermal actuation of a polyimide bimorph to produce long-travel deflection of each cilium and electrostatic actuation to provide a low-power hold-down mode. Each cell in the array consists of four orthogonally oriented cilia which, with proper drive signals, can produce object motion along any direction within the plane of the array. Adapting this array for use inside a scanning electron microscope (SEM) requires only a small mounting block and a modest multiconductor feedthrough. Improved thermal isolation within the vacuum chamber of the SEM drastically reduces the electrical input power requirements over those in air, while still allowing full positioning resolution. The addition of a gold ground plane coating to t...