Page 130 - Welding Robots Technology, System Issues, and Applications

Robotic Welding: System Issues 117

1. Be able to represent the robot manipulator motion based on the kinematic
and dynamic models, but also based on real-time data coming from the real
robot. That can be done using available mathematical and graphical
®
software packages, like Matlab for example. This latest objective clearly
indicates the need to access robot motion and status information in real-
time from the mathematical package.
2. Be able to develop applications to explore remotely the entire installation
(robot and welding application, for example) using standard programming
languages (C, C++, C#, Visual Basic, etc.).
3. Be able to integrate and explore intelligent sensors used to obtain
information from the process under control.
4. Enable users to explore the advanced programming capabilities of actual
robot controllers, namely the local programming capabilities, based on a
dedicated programming language complemented by extensive libraries of
functions, and the optimized manipulation capabilities based on trajectory
planning software that takes advantages of optimized kinematic and
dynamic models.
5. Enable users to build flexible manufacturing cells, which leads to the
possibility to explore the available industrial data network, the possibility
to distribute software to the various components of the system, and the
capacity to build remote software applications to control and monitor
industrial manufacturing cells;
6. Develop advanced Human Machine Interface (HMI) solutions to operate
with industrial systems, hiding from the users all the tricky details about
implementation, allowing them to focus on the operational details, i.e., to
focus on how systems work and how they can be explored efficiently.
7. Provide ways that could allow developers to focus on the important things
about the application they are building: the control algorithm, program
functionality and HMI. All the details related with communications, sensor
integration, etc., should be hidden from the user.

Taking into consideration these objectives the following programming models are
required:

1. Client-server model: there should be server code running on each cell
equipment, namely on the robot controllers and coordinating PLCs, that
could receive calls from the remote client computers, execute the
commands and return the results;
2. Remote Procedure Calls: this is the most usual method used to implement
communications between a client and a server on a distributed
environment. The client makes a call to a non-local function and the
selected RPC mechanism configures the call so that the proper computer,
server program and function are addressed, adding the necessary network
headers. The server program, running on the server machine, receives the
call, executes the selected function and returns the results obtained to the
client computer.