"Connecting and disconnecting for chain
self-reconfiguration with PolyBot", M. Yim, Y. Zhang, K.
Roufas, D. Duff and C. Eldershaw, IEEE/ASME Transactions
on mechatronics, special issue on Information Technology in
Mechatronics, 2003
Abstract
Chain modular robots form systems with many degrees of freedom which are
capable of being reconfigured to form arbitrary chain-based topologies.
This reconfiguration requires the detaching of modules from one point in
the system and re-attaching at another. The internal errors in the
system (especially with large numbers of modules) are such that accurate
movement of chain ends, required for the attaching of modules, can be
extremely difficult. A three phase docking process is described that
utilizes both open- and closed-loop techniques.
This process has been shown to work with an early version. Issues raised
during this testing have been addressed in a later version. Discussion
of these issues, their solutions and preliminary results of the testing
the latest version are given.
"Modular Reconfigurable Robots in Space
Applications", M. Yim, K. Roufas, D. Duff, Y. Zhang, C.
Eldershaw and S. Homans, Autonomous Robot Journal, special issue for
Robots in Space, Springer Verlag, 2003
Abstract
Robots used for tasks in space have strict requirements. Modular
reconfigurable robots have a variety of attributes that are well suited
to for these conditions, including: the ability to serve as many
different tools at once (saving weight), packing into compressed forms
(saving space) and having high levels of redundancy (increasing
robustness). In addition, self-reconfigurable systems can self-repair
and adapt to changing or unanticipated conditions. This paper will
introduce such a self-reconfigurable modular robot: PolyBot. PolyBot has
significant potential in the space manipulation and surface mobility
class of applications for space.
"Modular self-reconfigurable
robots", C. Eldershaw, M. Yim, D. Duff, K. Roufas and Y.
Zhang, Robotics for future land warfare seminar and
workshop, Defence Science Technology Organisation, Adelaide,
Australia, 2002
Abstract
The face of modern land warfare is changing rapidly. Defence
organisations around the world must be constantly
adjusting and improving just to maintain a comparative advantage over
their opponents. Robotics is one
particular area attracting growing interest amongst a number of
countries. Most of their work is following along
the conventional lines of designing specialised robots to perform
specific tasks. Such robots work tend not to be
multi-purpose and their performance suffers when forced to deal with
different environments.
This paper proposes using a more versatile solution: modular
self-reconfigurable robots. These are capable of
adapting their very structure to match the task and environment at hand.
Their extreme modular construction enables
easy, in-the-field diagnosis and repair by untrained users. The massive
redundancy inherent in such systems
allows a remarkably sustained performance in the face of partial damage.
These three key benefits: flexibility, maintainability and robustness
are clearly attributes which are useful to
armed forces around the world. However Australia, with its unique
defence requirements (due to geography, size
of active forces and types of deployment), is particularly in a position
to enjoy the important strategic benefits.
This paper discusses some of the benefits of such modular systems and
one particular experimental implementation:
PolyBot.
"A General Constraint-Based Control Framework with
Examples in Modular Self-Reconfigurable Robots", Y. Zhang, M. Fromherz, L.
Crawford, Y. Shang, IEEE/RSJ Intl. Conf. on Intelligent Robots
and Systems, Lausanne, Switzerland, Oct. 2002
Abstract
In this paper, we advocate a general constraint-based control framework that is
highly promising for building control systems with complex dynamic structures,
such as modular self-reconfigurable robots. In this framework, a controller
consists of constraint solving components distributed in a network of embedded
processors. Constraint solvers are goal oriented deliberative agents that can be
used as control regulators or as information retrievers. The framework is built
on the Attribute/Service Model (ASM), a middleware for coordinating actuators,
sensors and tasks in distributed real-time embedded systems. The communications
and coordination among the services are realized via shared attributes. Examples
of controlling a modular self-reconfigurable robot are illustrated in the paper.
"Sensor
Computation in Modular Self-Reconfigurable Robots", Y. Zhang, K. Roufas, C. Eldershaw,
M. Yim, D. Duff, Experimental Robotics VIII, Advanced Robotics
Series, Ed.
Springer, 2003
Abstract
Sensors play important roles in automatic systems; smart systems have to be
equipped with smart sensors. PolyBot, a modular self-reconfigurable robot
developed at the Palo Alto Research Center, is designed with a rich set of
sensors in each of its 5cm-cubed modules. These include infrared (IR),
accelerometers, potentiometers, force, and touch sensors. These sensors are
used: to determine the current state of the system and its environment; to
obtain the six degree-of-freedom offset between two docking plates for automatic
reconfiguration; to select the right gait for locomotion; and to trigger
different behavior modes in response to different terrain conditions. Sensor
computations are computational methods that, given raw sensor data, extract or
deduce the state information about the system. In general, there are two types
of sensor computation, forward computation and inverse computation. Analogous to
forward and inverse kinematics, forward sensor computation obtains state
information directly from sensor data; inverse sensor computation obtains state
information by solving a constraint or optimization problem using either
closed-form or numerical methods. This paper focuses on two interesting sensor
computations in PolyBot: IR 6 DOF ranging and accelerometer 2 DOF orientation.
"Massively Distributed Control Nets for Modular
Self-Reconfigurable Robots",
Y. Zhang, M. Yim, K. Roufas, C. Eldershaw, AAAI 2002 Spring Symposium on
Intelligent Distributed and Embedded Systems
Abstract
Massively Distributed Control Nets (MDCN) is a CAN based high-level protocol
that has the following features: (1) Three types of communication: individual,
group and broadcast, with eight priority levels. (2) Addressing of up to 254 nodes
and groups in standard CAN format, and up to 100,000’s in extended CAN format.
(3) I/O (node-to-node) and port (point/process-to-point/process) communications,
where I/O is mostly reserved for system processes with high priorities and short
message sizes, and port is for user applications, with lower priorities and
possibly large message sizes. Compared to the existing widely used high-level
CAN protocols, MDCN can address more communication nodes, has simpler APIs,
is easier and more efficient to implement. Also the protocol is transparent
to either a single CAN bus or a networked CAN buses. MDCN is currently
implemented in C for MPC555 TouCAN controller on the Real-Time Operating
Systems vxWorks, and in Java on host PC. The API is designed and implemented
for multi-threaded environments. MDCN is a general protocol that not only
can be applied to modular robots, but also can be applied to any industry
control or automation using CAN bus network with hundreds of communication nodes.
"Attribute/Service Model: Design Patterns
for Efficient Coordination of Distributed Sensors, Actuators and Tasks in
Embedded Systems",
Y. Zhang, M. Yim, K. Roufas, C. Eldershaw, D. Duff, Workshop on Embedded System
Codesigns 2002
Abstract
This paper proposes the Attribute/Service Model (ASM) and associated design
patterns as a general and simple framework for applications that require
programming with multiple tasks on multiple processors. This model enables
the programming of complex tasks with multiple sensors and actuators on highly
distributed yet tightly coupled systems by: making transparent the location of
where services run, simplifying the synchronization of multiple processes
concurrently changing the shared data, protecting that shared data and using
a simple unified protocol for communication. Associated design patterns such as
the event/trigger mechanism for general event-driven control and phase automata
for modular robots’ gait control are developed on ASM. ASM is designed for
distributed coordination of sensors, actuators and tasks for modular
self-reconfigurable robots; however it can be used for any multi-threaded
distributed embedded control network. ASM has been implemented both in C on
top of VxWorks on the MPC555 embedded microprocessors, and in Java on a host PC,
using Controller Area Network (CAN) as the communication medium.
It could be equally implemented on any real-time operating system using
any communication media.
" Reconfiguration Planning
for Modular Self-Reconfigurable Robots
",
A. Casal, PhD Thesis, Stanford, 2002
Abstract
Modular Self-reconfigurable (MSR) robotics is a new technology
with the potential to significantly expand the domain of robot
applications. The key characteristic of MSR robots is their ability
to change configuration automatically, enabling them to adapt their
shape to suit multiple, changing tasks. The underlying design philosophy
is to build complicated systems from a varying number of basic units,
or modules. Modules have degrees of freedom and share standard
connection interfaces allowing them to attach and detach from one
another. This makes them capable of re-arranging their positions and
connections within the robot, to transform the overall configuration.
The ability to self-reconfigure translates into great versatility,
making MSR systems true general-purpose robots. However, self-reconfiguration
introduces a difficult planning problem as the number of modules
(and degrees of freedom) in a robot increases. A practical solution
would automatically generate a sequence of module operations necessary
to transform one configuration into another. This involves planning for
the connectivity changes and motion trajectories of every module, while
taking account of restrictive motion constraints. Adding to the difficulty
is the fact that even though all MSR robots share the same design and
operating principles, particular module hardware designs result in strikingly
different approaches to reconfiguration. To date, few solutions have been
proposed, and no practical algorithms exist yet for some categories of MSR robots.
This thesis presents a new planning architecture for reconfiguration
that allows a MSR robot to efficiently transform between two arbitrary
configurations. The solution is the first to address a category of MSR
robot reconfiguration known as Chain Reconfiguration. The proposed method
is based on the integration of two complimentary components: a Connectivity
Planner and a Motion Planner. The Connectivity planner operates in a purely
topological domain, generating an ordered sequence of module connectivity
changes necessary to achieve the transformation. This sequence is passed to
the Motion Planner, whose role is to compute feasible motion trajectories,
accounting for geometry and physics, for all the modules involved in each
of the connectivity steps. When the Connectivity planner is combined with the
Motion planner, a complete Reconfiguration Planner is obtained.
Chain Reconfiguration MSR robots are characterized by the fact that, in order to
reconfigure, modules must move in groups or ”chains” to improve their reachability.
This is in contrast to other MSR robots, where a single module can move on its own,
and reconfiguration happens as a series of individual module motions. The hardware
design effort per module in Chain MSR robots is relatively simple compared to other
categories. However, Chain reconfiguration introduces additional challenging planning
requirements: solving the kinematics (forward and inverse) of groups of inter-connected
modules, maintaining overall stability under gravity, and avoiding collisions as the
module chains move. The Reconfiguration Planner in this thesis is specifically suited
to Chain Reconfiguration MSR robots, being the first of its kind.
To evaluate the proposed strategy, simulation results are examined for various
reconfigurations of PolyBot, a MSR robot developed and built at the Xerox Palo
Alto Research Center. The examples presented span a range of useful manipulation
and locomotion configurations, complex enough to warrant the use of an automatic
planner. Graphical animations illustrate the results of the Connectivity and
Motion Planners. The resulting behavior shows various PolyBot robots completing
reconfiguration while avoiding external obstacles and self-collisions, and
maintaining stability. Performance issues and limitations are discussed, along
with recommendations for future research.
"Evolution of PolyBot: A Modular Reconfigurable Robot",
D. Duff, M. Yim, K. Roufas, Proc. of the Harmonic Drive International Symposium,
Nagano, Japan, Nov. 2001, and Proc. of
COE/Super-Mechano-Systems Workshop, Tokyo, Japan, Nov. 2001
Abstract
Modular, self-reconfigurable robots show the promise of great versatility,
robustness and low cost. This paper presents examples and issues in realizing
those promises. PolyBot is a modular, self-reconfigurable system that is being
used to explore the hardware reality of a robot with a large number of
interchangeable modules. Three generations of PolyBot have been built over
the last three years which include ever increasing levels of functionality
and integration. PolyBot has shown versatility, by demonstrating locomotion over
a variety of terrain and manipulating a variety of objects. PolyBot is the first robot
to demonstrate sequentially two topologically distinct locomotion modes by
self-reconfiguration. PolyBot has raised issues regarding software
scalability and hardware dependency and as the design evolves the issues of
low cost and robustness are being addressed while exploring the potential of modular,
self-reconfigurable robots.
"Closed Chain Motion with Large Mechanical Advantage", M.
Yim, D. Duff, Y. Zhang, IEEE/RSJ Intl. Conf. on Intelligent Robots
and Systems, Hawaii, USA, Oct. 2001
Abstract
One of the constraints that severely limit the capability of highly
redundant manipulator arms is the actuator torque limits. This paper
presents a way to achieve large effective forces from weak actuators
by exploiting large mechanical advantage that results from systems
near singularities. While large mechanical advantages have been
applied near singularities in many instances, this method allows the
application of this large force over a large distance. It is applied
specifically to closed chain mechanisms and demonstrated on the
PolyBot modular self-reconfigurable robot.
"Software Architecture for Modular Self-Reconfiguable Robots",
Y. Zhang, K. Roufas, M. Yim, IEEE/RSJ Intl. Conf. on Intelligent Robots
and Systems, Hawaii, USA, Oct. 2001
Abstract
Modular,
self-reconfigurable robots show the promise of great versatility, robustness
and low cost. However, programming such robots for specific tasks, with
hundreds of modules and each of which with multiple actuators and sensors,
can be tedious and error-prone. The extreme versatility of the modular
systems requires a new paradigm in programming. In this paper, we present
new software architecture for this type of robot, in particular PolyBot,
which has been developed through its third generation. The architecture,
based on the properties of the PolyBot electro-mechanical design, features a
multi-master/multi-slave structure in a multi-threaded environment, with
three layers of communication protocols. The architecture is currently being implemented for Motorola PowerPC
using vxWorks.
"Modular Reconfigurable Robots in Space Applications",
M. Yim, K. Roufas, D. Duff, Y. Zhang, S. Homans, 10th Intl. Conf. on Advanced Robotics
Budapest, Hungry, Aug. 2001
Abstract
Robots used for tasks in space have strict requirements.
Modular reconfigurable robots have a variety of attributes that
are advantageous for these conditions including the ability to serve
as many tools at once saving weight, packing into compressed forms saving
space and having large redundancy to increase robustness. Self-reconfigurable
systems can also self-repair as well as automatically adapt to changing conditions
or ones that were not anticipated. PolyBot may serve well in the space manipulation
and surface mobility class of space applications.
"Modular Robot Control and Continuous Constraint Satisfaction",
M. Fromherz, T. Hogg, Y. Shang, W. Jackson, IJCAI-01 Workshop on Modelling and Solving
Problems with Constraints, Aug. 2001
Abstract
Continuous constraint satisfaction is at the core
of many real-world applications. One example is
in the control of modular, hyper-redundant robots,
which are robots with many more degrees of freedom
than required for typical tasks. Casting
the control problem as a constraint problem is a
promising approach for robustly handling a variety
of non-standard constraints found in such robots.
However, before we can scale to the many degrees
of freedom and nonlinearities of this system and
deploy constraint solvers for embedded, real-time
control, we need to better understand the complexity
issues arising in these problems. In this paper,
we first present a parametric model for robotic control.
We then study the complexity of related but
simpler problems by analyzing two classes of artificial
constraint satisfaction problems inspired by
(discrete) 3-SAT problems, which have a strong relation
between structure and search cost. With this,
we also propose a generic benchmarking model for
continuous constraint satisfaction problems.
"Motion Planning of Legged Vehicles
in an Unstructured Environment",
C. Eldershaw and M. Yim, IEEE Intl. Conf. on Robotics and Automation
(ICRA), Seoul, Korea, May 2001
Abstract
A planner for statically-stable motion of a legged robotic vehicle over
an uneven terrain is presented that can plan the footplacement of
individual legs for highly cluttered terrain. A method for determining
the traversability over a generic discretised height map terrain is
presented. Planning is broken into two levels of refinement to reduce
the overall complexity and incorporates a number of heuristics. The
planner has successfully planned the motion of 6 and 8 legged
configurations of the Xerox PARC PolyBot modular reconfigurable robot as
well as the CMU Ambler in simulation over arbitrarily complex terrain. A
distributed implementation of the planner has also been shown on
PolyBot's distributed computational platform.
"Joint Solutions of Many Degrees-of-freedom Systems
Using Dextrous Workspaces",
S.K. Agrawal, L. Kissner, M. Yim, IEEE Intl. Conf. on Robotics and Automation
(ICRA), Seoul, Korea, May 2001
Abstract
In recent years, several studies have focussed on robotic systems with many degrees-of-freedom.
Such robots often have stringent joint limits. For motion planning, a key question is to find
feasible joint solutions of the system for a given position and orientation of the end-effector.
In the presense of joint limits, the solutions are found by searching the joint space
using heuristics. In this paper, we propose a simple algorithm to construct the joint solutions for
a robot chain with many degrees-of-freedom and joint limits, using dextrous workspaces. The
algorithm provides a set of sufficient conditions to quarantee feasible joint solutions in
the presence of limits. The procedures are illustrated by theory and experiments on PolyBot,
a modular robot developed at Xerox PARC.
"Climbing with Snake-like Robots",
M. Yim, S. Homans, K. Roufas, Proc. of IFAC Workshop on Mobile Robot Technology, Jejudo, Korea,
May 2001
Abstract
This paper presents an implementation of a long serial chain robot tha t
can climb stairs in a "snake-biting-its-tail" loop form, climb up ramps
using a travelling wave gait and by adding small spikes or cleats, can
also climb near vertical porous materials. The gaits are controlled with
a gait control table w hich is a simple but powerful way to coordinate
the motion of many degrees of fr eedom. The gaits are implemented on
PolyBot G1v4, a self-sufficient modular reco nfigurable robot with
onboard power, computation, sensors and actuators.
"
Heuristic Algorithms for Motion Planning ",
(3.7M pdf)
C. Eldershaw, PhD Thesis, Oxford, 2001
Abstract
Motion planning is an increasingly important field of research. Factory
automation is becoming more prevalent and at the same time, production
runs are shortening in the name of customisation. With computer
controlled equipment becoming cheaper and more modular, setting up
near-fully automated production lines is becoming fast and easy. This
means that the actual programming of the robots and assembly system is
becoming the rate determining step. Automated motion planning is a
possible solution to this - but only if it can run fast enough.
Many heuristic planners have been created in an attempt to achieve the
necessary speeds in off-line (or more ambitiously, on-line) processing.
This thesis aims to show that different types of heuristic planners can
be designed to take advantage of specialised environments or robot
characteristics. To show this, three distinct classes of heuristic
planners are put forward for discussion.
The first of these classes, addressed in Chapter 2, is of very generic
planners which will work in virtually all situations (ie. almost any
combination of robot and environment). This generality is obviously
useful when lacking more specific domain knowledge. However these
methods do suffer performance-wise in comparison with more specialised
planners when there are characteristics of the problem which can be
targeted.
Chapter 3 moves to planners which are designed to specifically address
certain peculiarities of the environment. Particular focus is given to
environments whose corresponding configuration-spaces contain narrow
gaps and passages.
Finally Chapter 4 addresses a third class of planners: those which are
designed for specific types of robots and movements. The particular
focus is on locomotion for legged vehicles.
For each of these three classes, some discussion is made of existing
planners which can be so characterised. In addition, a novel algorithm
is introduced in each as an example for particular consideration.
"Six Degree of Freedom Sensing for Docking Using IR RED Emitters
and Receivers", K. Roufas, Y. Zhang, D. Duff, M. Yim,
Experimental Robotics VII, Lecture Notes in Control and Information Sciences
271, Daniela Rus and Sanjiv Singh Eds. Springer, 2001
Abstract
Six
DOF offset sensing between two plates is important for automatic docking
mechanisms. This paper presents an easy and inexpensive implementation of such a
system using four commercial-off-the-shelf (COTS) infrared (IR) light
emitting diode (LED) emitters and two COTS IR receivers on each of two
docking plates. The angular intensity distribution of an emitter and the sensitivity
distribution of a receiver allow for estimation of the angle and distance
between them. Simple experiments have been conducted indicating that such a setup
is able to give positional offset in any of 6 degrees of error (x, y, z,
pitch, roll, and yaw) within a range. A theoretical framework is also established using least squares
minimization. The theoretical framework is general and applies to other
configurations of emitter and receiver parts and positioning.
"Connectivity Planning for Closed-Chain Reconfiguration",
M. Yim, D. Goldberg, A. Casal, Proc. of SPIE, Sensor Fusion and
Decentralized control in Robotic Systems III, Volume 4196, Nov. 2000
Abstract
Modular reconfigurable robots can change their connectivity from one ar
rangement to another. Performing this change involves a difficult
planning probl em. We study this problem by representing robot
configurations as graphs, and gi ving an algorithm that can transform
any configuration of a robot into any other in O(log n) steps. Here n is
the number of modules which can attach to more tha n two other modules.
We also show that O(log n) is best possible.
"Predictable Motion of Hyper-redundant Manipulators
Using Constrained Optimization Control",
M. Fromherz and W. Jackson, Int. Conf. on AI 2000 (IC-AI'2000), Las Vegas, NV, June
2000
Abstract
Hyper-redundant robotic manipulators are robots that
have many more degrees of freedom than required for a
typical task such as grasping an object in 3D space. The
large number of joints, which may range from dozens to
thousands, offers both opportunities and challenges for
the control of such robots. An opportunity is to use the
extra degrees of freedom to optimally control multiple
objectives. A challenge is to deliver predictable behavior
despite the large number of possible configurations. In
this paper, we propose to use a control approach based on
constrained optimization. We discuss a representative
example for an under-constrained task and suggest and
analyze possible solutions that ensure predictable
behavior.
"PolyBot: a Modular Reconfigurable Robot",
M. Yim, D. Duff, K. Roufas, IEEE Intl. Conf. on Robotics and Automation
(ICRA), San Francisco, CA, April 2000
Abstract
Modular, self-reconfigurable robots show the promise of great versatility, robustness and low cost.
This paper presents examples and issues in realizing those promises.
PolyBot is a modular, self-reconfigurable system that is being used to explore the hardware reality
of a robot with a large number of interchangeable modules. PolyBot has demonstrated
the versatility promise, by implementing locomotion over a variety of terrain and
manipulation versatility with a variety of objects. PolyBot is the first robot to
demonstrate sequentially two topologically distinct locomotion modes by self-reconfiguration.
PolyBot has raised issues regarding software scalability and hardware dependency and as
the design evolves the issues of low cost and robustness will be resolved while exploring
the potential of modular, self-reconfigurable robots.
"Two Approaches to Distributed Manipulation", M. Yim, J.
Reich, A. Berlin, Distributed Manipulation, ed.
by H. Choset and K. Bohringer, Kluwer Academic Publishing, 2000
Abstract
Two radically different approaches to distributed manipulation are reviewed.
They each address scalability and manufacturing issues while producing forces
sufficient to move macro-scale objects in different ways. The airjet system
achieves scalability and manufacturability through macro-scale planar batch
fabrication technology while PolyBot is modular, enabling mass production. Where
PolyBot is suited to couple to non-planar objects through variable out-of-plane
motion of the cilia, airjets are optimized for manipulation of planar objects
with delicate surface features. The designs of both systems are well suited to
hierarchical computation and communication to enable scalability without an
explosion in the resource requirements.
"Modular Reconfigurable Robots, An Approach To Urban Search and Rescue",
M. Yim, D. Duff, K. Roufas, 1st Intl. Workshop on
Human-friendly Welfare Robotics Systems, Taejon, Korea, Jan.
2000
Abstract
Modular, self-reconfigurable robots show the promise of great versatility, robustness
and low cost which are all elements for a successful urban search and rescue (USAR) system.
This paper presents examples and issues in realizing those promises. PolyBot is a modular,
self-reconfigurable system that is being used to explore the hardware reality of a robot with
a large number of interchangeable modules with applications to USAR. PolyBot has demonstrated
locomotion versatility over a variety of terrain and manipulation versatility with a variety of
objects. PolyBot is the first robot to demonstrate sequentially two topologically distinct
locomotion modes by self-reconfiguration. PolyBot has raised issues regarding software
scalability and hardware dependency and will continue to raise issues as the design evolves
to resolve preceding issues and explore the potential of modular, self-reconfigurable robots.
Finally this paper addresses the issues required to make robot systems useful for current
USAR applications.
"Self-Reconfiguration Planning for a Class of Modular Robots",
A. Casal and M. Yim, Proc. of SPIE, Volume 3839, 1999
Abstract
Modular self-reconfigurable robots consist of large numbers (hundreds or thousands) of
identical modules that possess the ability to reconfigure into different shapes as required
by the task at hand. For example, such a robot could start out as a snake to traverse a
narrow pipe, then re-assemble itself into a six-legged spider to move over uneven terrain,
growing a pair of arms to pick up and manipulate an object at the same time.
This paper examines the self-reconfiguration problem and presents a divide-and-conquer
strategy to solve reconfiguration for a class of problems referred to as closed-chain
reconfiguration. This class includes reconfigurable robots whose topologies are described
by one-dimensional combinatorial topology. A robot topology is first decomposed into a
hierarchy of small "substructures" (subgraphs of modules) belonging to a finite set.
Basic reconfiguration operations between the substructures in the set are
precomputed,
optimized and stored in a lookup table. The entire reconfiguration then consists of an
ordered series of simple, precomputed sub-reconfigurations happening locally among the
substructures.
"Towards Constraint-based Actuation Allocation
for Hyper-redundant Manipulators",
M. Fromherz, M. Hoeberechts, W. Jackson, CP'99 Workshop on Constraints in Control (CC'99),
Alexandria, VA, Oct. 1999
Abstract
Hyper-redundant robotic manipulators are robots that have many more degrees of freedom than
required for a task such as grasping an object in 3D space. The large number of joints,
possibly ranging from dozens to thousands, offers both challenges and opportunities for
control of such robots. A challenge is to develop algorithms that scale and adapt to different
configurations while taking into account a variety of robot constraints. An opportunity is to
use the extra degrees of freedom to optimally control multiple objectives. In this paper,
we propose to use a control approach based on constrained optimization. We present robot
and task models and discuss first results.
"A Comparison Between Contact And Non-Contact Distributed Manipulation",
M. Yim and A. Berlin,
IEEE Intl. Conf. on
Robotics and Automation (ICRA), 1999
Abstract
The manipulation of objects using an array of actuators and vector field control
has had growing interest. We will present two systems that represent a class of
actuators and styles of distributed manipulation. The first is a macroscale modular
reconfigurable robot that is used to examine arrays of 1 degree of freedom (DOF),
2 DOF and 3 DOF manipulators. The second is a non-contact platform has been that can
manipulate flat sheets of material using arrays of fixed air-jets. These two systems
are compared and contrasted with an analysis on the implications for control, design parameters,
and the application spaces that fit those parameters.
"New Locomotion Gaits", M. Yim, IEEE Intl. Conf. on
Robotics and Automation (ICRA), San Diego, CA, 1994
"Locomotion with a Unit Modular Reconfigurable Robot"M. Yim, PhD Thesis, Dept. of Mech. Eng. Stanford Univ. 1994
(1.4M pdf file)
"Locomotion Gaits with Polypod", M. Yim, Video Proc. of the IEEE
Intl. Conf. on Robotics and Automation, San Diego, CA. 1994.
"A Reconfigurable Modular Robot with Many Modes of Locomotion",
M. Yim, JSME Intl. Conf. on Advanced Mechatronics, Tokyo, Japan, 1993
