SMART - Faster, Easier, Less Expensive Robot System Integration & Control

Telerobotic systems are designed to allow an operator to control a remote vehicle in a hazardous environment. In designing a system for remote operation, the developer has numerous off-the-shelf hardware components that can be utilized in the deployed system, such as manipulator arms, base platforms, camera systems, sensor systems, and a variety of possible input devices, such as driving wheels, toggle switches, spaceballs, and force feedback masters. Integrating these components into a useful, functional system, without overwhelming the end-user is a daunting task.

The Intelligent Systems and Robotics Center (ISRC) of Sandia National Laboratories has developed and patented an inherently stable, modular software architecture for telerobotics, called SMART: Sandia's Modular Architecture for Robotics and Teleoperation. SMART is a software tool for building telerobotic systems from commercial hardware that achieves maximum utility from the hardware, and minimum complexity for the end-user.

SMART:

• Enables faster and easier control software development
• Sets specifications for re-usable modules for each system component
• Offers a GUI (graphical user interface) to assemble components on-screen
• Checks the chosen combination of system components for completeness
• Assembles and compiles separate control code for each chosen system behavior
• Guarantees stability of the software control system (when modules meet SMART individual stability criteria)

SMART consists of three components:

1. The SMART Editor is a tool for the system developer to define, develop, and generate telerobotic behaviors. It consists of a graphical user interface, whereby the developer can place icons representing SMART modules onto layered grids. The Editor then will verify the proposed behaviors, determine the optimal distribution of modules onto the available real-time computing resources, and generate the source code defining the behaviors. This source code is then linked with the available module libraries to create the run-time executables. The Editor also generates the prototype scripts needed to build a SMART Supervisor for a given application.
2. The SMART Supervisor is a graphical front-end to the SMART Real-Time Engine. It allows the operator to quickly switch behaviors, change module settings, and display results.
3. The SMART Real-Time Engine represents the primary component of the SMART environment, and consists of all of the algorithms, device drivers, state engines, and servo-loops needed to implement a telerobotic control system.

Using the SMART approach, a telerobotic system is built up as a series of capabilities called behaviors. Each behavior is built from a series of modules, where each module represents a component of the system (i.e., input device, connection, filter, sensor, constraint, or robot mechanism). To conduct a telerobotic task, the operator will select the appropriate behavior for each subtask by pushing a "button" on the control panel that represents each behavior. This causes all of the modules involved to continuously process inputs and sensor data and generate outputs until a new task is chosen.

FEATURES

Useful behaviors that can be created using SMART include the following:

• Multi-arm telemanipulation enables two arm modules to work together in a coordinated fashion.
• Prescribed motion paths allow simultaneous, articulated joint movement using a kinematic module for each arm, critical to converting a manipulator to a robot.
• Because it can be very confusing understanding which direction to move a robot using only the camera, a SMART module enables the robot to move in a camera coordinate frame. The input is intuitive, allowing movement on the screen to correlate with the camera, no matter what orientation the camera is in.
• Collision avoidance with obstacles the robot may encounter is possible using sensors such as capacitive sensors located in plates, collars, and skins. Trajectory planning and "soft" joint limits enable close proximity movement, allowing the robot to complete tool changes and stowing of equipment without banging into itself.
• Joint-locking enhances gross positioning and anti-collision, allowing the operator to specify certain arm joints that can be locked in place, while allowing others to remain mobile. For example, if the arm reaches through a car window, a portion of the arm can be held in place so it doesn't touch the car frame, while the rest of the arm is free to move about inside the vehicle.

SMART has been used to implement sophisticated telerobotic controllers with capabilities such as generic force reflection, graphical monitoring and reviewing, multi-sensor fusion, impedance control, multi-robot control, autonomous robot control, and kinesthetic virtual reality.

SMART's modular concept ensures that software control modules for each component are interchangeable. Using SMART makes it easier, faster, and less expensive for the designer to develop controls for new system configurations. It allows the coordinated motion of multiple arms mounted on a variety of bases, permitting the rapid synthesis of any vendor's hardware, software (within a particular module), or sensors with real-time robot control systems. Approximately 200 modules are currently available. These can be exchanged rapidly, enabling designers to customize the system to suit their preferences.