# An Overview of Industrial Robots Control and Programming Approaches
## 4 Innovative Control Approaches
### Open Controller  
Despite the positive outcomes achievable with the control solutions described in Sections 4.1 and 4.2, access to the lowest control layers remains restricted for most IRs. Therefore, some research works have proposed the replacement of the original equipment (Figure 2c) and the implementation of an open, fully programmable control system [51; 52]. Important contributions in this area were reached with the European project OSACA (Open System Architecture for Control within Automation Systems), in Japan with the OSEC (Open System Environment for Controllers), and in the US with the OMAC (Open Modular Architecture Control). Many of the proposed solutions utilize a PC-based architecture (see [53; 54; 55; 56; 57; 58]), the PC itself being an open, versatile, and highly customizable platform. For example, in [58], the authors proposed a low-cost control system capable of being implemented in obsolete IRs. The control architecture consisted of a standard PC and an interface based on FPGA (Field-programmable Gate Array). The PC is responsible for motion interpolation, kinematics computation, and transmitting the joint position reference and receiving the current position. The role of the FPGA is to decode feedback position data, compute the control output and commutation signals, and transmit such data to the actuators. With the same goal, in [59], the original robot controller is replaced by an embedded industrial CompactRIO controller programmed in LabVIEW.  
For industrial facilities where PLCs are already utilized in other machine control applications, moving to PLC-based robotic controls (as in [60]) would be particularly convenient by leveraging (i) internal know-how of engineers and technicians (i.e., simplified training), (ii) already installed hardware (cabinets, electronic modules, cables, etc.) and software (e.g., programming editors, simulation and debugging tools, interfaces) environments, and (iii) available documentation (i.e., simplified troubleshooting and maintenance). Other important benefits include the easy integration of multiple devices within the same production environment with efficient interfaces and communication protocols. As an example, let us consider a robotic cell for material handling, where infeed/discharge conveyors, pallet dispensers, and other system components must cooperate with the IR to achieve the desired functionality. In this case, the use of a reduced number of controllers (ideally one) and boards would greatly lower the complexity of the overall production system and ease its setup and commissioning phases by limiting the effort spent on programming and interfacing the installed mechatronic devices. The most widespread platforms for developing open solutions for logic and motion control in automation, already integrated within their related commercial PLCs, are Siemens Sinumerik, Bosch IndraMotion, and Beckhoff TwinCAT, the latter being particularly flexible as it potentially turns any standard PC into an effective PLC with real-time I/O exchanges.  
Naturally, the replacement of the original controllers, although interesting for the development of fully customized control algorithms aiming, e.g., at improving the performance of existing machines, may not be feasible in all industrial installations due to high costs and safety reasons. Indeed, on the one hand, substituting the original hardware requires significant expenses and time for establishing the new setup. On the other hand, it leads to the loss of safety requirements already established by the manufacturers, which are quite intricate to be reproduced in new controllers.