The K-1207i, pictured above, is a 7-axis, kinematically-redundant manipulator. RRC manipulators are the lightest electric-drive articulated robot arms available for a given reach and payload. For instance, this K-1207i model, offering a 50 inch reach and a 35lb. continuous-duty payload, weighs only 155lbs. "Continuous-duty payload" represents the maximum load that the system can handle in any arm pose, indefinitely. The useable payload capacity increases considerably as the payload is manipulated closer to the 'heart' of the work envelope or when leverage and torque distribution algorithms are employed. The company currently offers a line of highly dexterous, force/position-controlled, modular, electric manipulators in use by U.S. federal agencies, government contractors, industrial corporations and universities working on man-equivalent robotic and telerobotic applications. RRC kinematically-redundant, electric robots offer high bandwidth force control, unprecedented 'human-like' dexterity with a very high degree of precision in a compact lightweight package. The standard seven degree-of-freedom manipulator configurations are built from a family of modular actuators covering a wide range of torque capacities. Manipulators of varying size, capacity and redundancy can be built from the family of modules having output torques from 25 in-lbs to 43,000 in-lbs. Units with 7 axes in series and 17 axes in branching topologies, all operating under real-time coordinated control, have been built.
Key features of this technology include: Dexterity RRC manipulators are kinematically redundant, incorporating seven or more degrees of freedom disposed in a roll-pitch-roll configuration. In combination, this 7-DOF geometry displays the highest level of dexterity available today. This type of arm can position and orient an end effector throughout a complete sphere, with an infinite range of arm poses. In addition, this topology allows the arm to fold compactly, a valuable feature in operations requiring manipulation through risers or small portholes, as well as minimizing the stowage requirements when safed. While manipulators with fewer degrees of freedom can be produced using the same standard set of modules, the increase in dexterity of redundant manipulators is extremely beneficial in increasing part accessibility, avoiding obstacles in the workspace, and greatly simplifying programming. Torque-Loop Servo Control RRC manipulators utilize a patented torque-loop servo control system. The innermost servo control loop is a torque loop. A semiconductor strain gauge array incorporated in each joint actuator is employed to measure and control the joint output torque. Torque loop bandwidths vary depending upon actuator size, but range from 40 to 60Hz. In addition to controlling actuator dynamics and eliminating apparent joint friction, these torque loops can be utilized with impedance control algorithms to achieve extremely high bandwidth force control at the tool without the need for additional hardware. Modular Arm Construction
This modular construction allows for manipulator configurations covering a broad range of sizes, payloads, and kinematic configurations for different applications, using all standard components. All modules of a particular size are internally identical. The difference between a roll module and a pitch module, for example, is simply the attachments between their adjacent joints. In addition, by selecting different drive ratios and motor windings, the torque and speed of an actuator package can be tailored to the application. Precision With a fixed payload, RRC manipulators afford positioning repeatability of better than 0.05mm, standard deviation, once the system has achieved thermal equilibrium. The K-2107HR, a 2 meter 7-DOF model optimized for positioning resolution, provides measuring repeatability of 0.013mm. Arm Mounted Servo Electronics Our i-Type manipulators incorporate an advanced, fully digital distributed servo control system in which miniature DSP-based servo modules, each containing all necessary servo electronics (communication, data acquisition, PWM amplifier, computing, etc.), are co-located with the actuators in the manipulator. This distributed hardware architecture eliminates the complex internal arm harness previously required, reducing it to a single power bus and one triax cable for communications between the on-board servo modules and the remotely-located 'high-level' controller (plus user tooling and safety circuitry). This on-board electronics system is particularly valuable for mobile vehicle installations, since the size of the control cabinet is dramatically reduced.
The R2 Control SoftwareTM provides the most advanced robotic control capabilities in the industry. It supports an open architecture at each level of control to facilitate third party application and control development and integration. The R2 Control Software has been packaged as an industrial turnkey controller, which executes under the Windows NT 4.0®, Windows Embedded NT®, Windows 2000®, and Windows XP®, operating systems in conjunction with the INtime®, real-time extension. The robot controller consists of two primary components of operation; the INtime real-time component (R2 RTC) and the NT client-server upper control level component. The R2 RTC provides deterministic, hard real-time control with typical loop times of 1 to 4 milliseconds. This component performs trajectory planning, Cartesian compliance and impedence force control, forward kinematics, inverse kinematics, and advanced heavy deposition welding. A customer can interface
with any level of the controller. The controller can accept commands
in the form of high level Cartesian goal points down to low level servo
commands of joint position, torque or current. An off-line/on-line
programming and simulation environment is available, which allows the controller
to use a sophisticated world model database in a real-time fashion.
Robotics Research's
dexterous manipulators have been adopted as primary testbeds for research
in man-equivalent telerobotics by NASA Johnson Space Center and NASA Jet
Propulsion Laboratory, the U.S. National Institute of Technology and Standards,
Oak Ridge National Laboratory, and Ford Motor Company's Advanced Manufacturing
Technology Department.
In parallel with
its commercial product manufacturing operations, Robotics Research has
worked under contract with industrial customers and government agencies
to adapt its proprietary mechanical design and control technology to new
applications. For example, the company has demonstrated the assembly
of complex gear trains utilizing its manipulator products and joint torque
based impedance control algorithms.
Control of robot
force with an end-point force/torque sensor involves modifying the robot
position commands based on the sensed forces. This provides very
low bandwidth force control, typically less than one cycle per second.
Since the parts are rigid, excessive forces are encountered before the
system can respond. Compliant tools, with enough compliance to perform
the task, limit positioning capability beyond acceptable levels.
By utilizing the high bandwidth force control embodied in Robotics Research's
manipulator technology, excessive forces do not occur and the capability
for accurate positioning is retained.
There is a broad
range of similar assembly and contact process applications that cannot
be performed with current industrial robot control technology. Robotics
Research's open architecture controller and library of software control
capabilities, along with the advanced features of RRC's manipulators, provide
the tools required for the successful automation of these applications.
Standard Manipulator
Configurations: I K-707i
I K-807i I K-1207i
I K-1607i I
K-1807i
I Photo K-807i
I Module Family
I Servo-Gripper
I 21 DOF Testbed
I Servicing
Aid Tool I Smart
Crane Ammunition Transfer System I Quad Track UGV I
RRC
Technology Description (.PDF)
If you are interested
in receiving more information about our company and products, please contact
us.
P.O.
Box 62298
Cincinnati,
OH 45262-0298
513.831.9570;
FX. 586.816.0841
kakowalski@aol.com Keith
A. Kowalski
peismann@aol.com Paul
H. Eismann
Copyright © 1998-2012 Robotics Research Corporation
All
rights reserved
|
RRC
manipulator mechanisms are modular. In this patented design, each
joint module contains a DC brushless motor component set, harmonic drive
gear reducer, power-off brake, sealed axis bearings, drive output position
and torque transducers, and wiring harness segment integrated into a lightweight
aluminum structure. Each self-contained joint module is joined to
its adjacent modules by quick-disconnect band clamps. Two adjacent
modules can be decoupled in seconds facilitating maintenance or retrofit.
R2
Control Software
