Development of a Universal Control Unit and Advanced Calibration Methods for Repurposing Obsolete Robots

INOMECH Ltd. is implementing the project "Development of a Universal Control Unit and Advanced Calibration Methods for Repurposing Obsolete Robots" (CZ.01.1.02/0.0/0.0/20_321/0024631). This project is financially supported by the European Union under the Operational Programme Enterprise and Innovation for Competitiveness (OPPIK).

This research and development project, characterized by a high level of technology and innovation, is focused on the repurposing of outdated robots lacking control electronics or equipped with obsolete control systems, bringing them to a state where they can be used for new applications.

The main output of the project is a prototype of a Universal Robot Control Unit. It is built on an open hardware and software platform, using components with high computational performance to handle complex tasks such as robot error compensation. The hardware and software solution is low-cost and utilizes commonly available market components. The platform is open to modifications and research by third parties.

Another output is a prototype of a Refurbished Robot with Control System. The robot's mechanics were fully identified and restored – including gearboxes, cabling, feedback systems, drives, paintwork, etc.

Additional outputs include a validated Calibration and Correction Procedure. This involves mathematical and metrological methods for determining the precise dimensions of the robot using artifacts. It also includes a procedure for determining corrections to improve imperfections caused by gearbox kinematics, mechanical structure compliance, and assembly inaccuracies.

INNOBOT - Robotic Platform

A robotic platform for schools, enthusiasts, and control system developers. The platform is based on the open-source BCN3D MOVEO robot, which has been modified using our expertise in mechanical engineering. The geometry of the 3D-printed parts has been adjusted for improved printability, ease of assembly, and geometric accuracy of the rotational axes.

This platform is freely available for download, and we also offer it in a pre-assembled state at innobot.eu.

Obsolete Robot Refurbishment

As part of the project, an outdated KUKA KR15-2 robot in as-is condition without a control unit was revitalized. The robot underwent mechanical refurbishment. A key requirement for successful and cost-effective revitalization is the ability to eliminate dependence on proprietary and outdated servo drives.

A procedure was developed that allows the original servos to be replaced with any drive of choice (stepper motor, stepper motor with feedback, or servo drive). As part of this adaptation, external safety brakes were developed and implemented, serving as an interface between the robot’s gearbox and the new drive.

This revitalization also included a new electrical cabinet containing servo drives and additional hardware necessary for implementing the new control system.

Development of Control Unit

The control unit is based on two equally important and mutually dependent components: hardware architecture and software architecture. The hardware for the unit was selected with an emphasis on low cost and general availability. Similarly, the software relies on the use of open-source and continuously developed components and frameworks.

Robot Calibration

For robot calibration, the project built on previous collaboration with the Faculty of Mechanical Engineering at CTU in Prague. The goal is to utilize the RedCam measuring device, which has six degrees of freedom, along with a calibration process to improve the robot's positioning accuracy. RedCam enables the analysis of errors between the desired and actual robot movements, and the measured data is used in a calibration algorithm.