Modular mechanical engineering made easy: Rexroth Motion Controls for electro-hydraulic axes

Cost pressure and the shortest possible development periods drive the trend towards modularization of machinery and plants. Constructional engineers are looking for solutions in which they can freely combine electro-mechanical and electro-hydraulic axes and scale them in accordance with the requirements of the respective application without the need for major software interventions.

Rexroth simplifies this modularization with a finely graded range of motion controls for electro-hydraulic axes. With the same open programming standards and engineering tools, they include a broad spectrum ranging from single-axis controllers without control cabinets to the control cabinet versions up to a multi-axis controller for a number of electro-hydraulic and electro-mechanical axes. 

Multi-Ethernet interfaces and standards, such as OPC UA, guarantee the seamless horizontal and vertical networking of the electrified hydraulics. Thus, they can be integrated independently of the control unit into different automation architectures up to industry 4.0 environments. 

The single- and multi-axis controls for hydraulic actuators close the control loop in a decentralized manner and unburden the higher-level control system. Rexroth is the only manufacturer using identical control hardware platforms as well as integrated software standards based on IEC 611331-3 and identical engineering tools for all intelligent drives. This provides the machine manufacturers with large degrees of freedom, with minimum cross-technology software interventions, and the option to provide varying numbers of drives in their concepts in accordance with customer-specific requirements. Program parts which have been written once can be simply transferred to all motion controls. 

Digital twins shorten time to market 

Rexroth software automatically considers the non-linearity of fluid technology and compensates it. With respect to the higher-level control system, hydraulic drives thus show the same behavior as electro-mechanical drives. For this purpose, Rexroth has relocated previously purely hydromechanical functions into the software. Pre-defined, best-in-class hydraulic controllers integrated there assume the regulation of position, speed, path/force, various synchronizations of several cylinders or the path-dependent braking. The Wizard-supported commissioning does not require any deeper knowledge in hydraulics. 

For the design and configuration of electro-hydraulic axes, Rexroth provides virtual images of the motion controls and their hydraulic actuators. With them, machine and system manufacturers can validate their concepts on the computer and avoid under- or overdimensioning without having to build a prototype first. Additionally, the control simulation enables the programming and validation of movements before or during the machine assembly. This reduces the time to market and the engineering costs significantly.

Intelligent, connectible hydraulics by Rexroth offer all physical advantages of fluid technology, with the same automation-technical degrees of freedom and the same comfort as offered by their electro-mechanical counterparts.