Advanced Position Control for CNC machines
PROBOT uses model predictive control to improve CNC machine precision. It was tested on a gantry-type laser cutting machine, demonstrating reduced maximum deviation between the tool and target geometry by 49% compared to normal machine performance. This gain was realized through a software upgrade alone, without requiring mechanical changes. The increased precision provided by PROBOT offers offers an option to increase the speed/productivity while keeping accuracy at the normal level. PROBOT is integrated into Beckhoff’s TwinCAT3 environment for this laser cutting machine application and can also be integrated into other open automation environments to enhance precision for a variety of machine tools and industries.
Source: Bystronic
PROBLEM
Recent advancements in mechanical design have pushed CNC machines close to their technological limits, limiting further improvements of actuators, sensors, and broad machine designs. Further performance gains must now come from specialized software and algorithms tailored for specific machine tools. Current state-of-the-art motion planning approaches still have potential for refinement, as evidenced in research on laser cutting tools. While many approaches to enhance contour tracking accuracy are in use today, more complex computational algorithms like model predictive control have yet to be fully industrialized. This has prevented many advanced machines from achieving their full capabilities in terms of precision, productivity, and motion optimization.
SOLUTION
PROBOT is configured as a reference tracking feedback controller for CNC machine axes. The trajectory evolution is largely deterministic as the required toolpath is predefined by the designed products that are produced. Readily available motion planners can therefore provide trajectory forecasts for each axis in advance. Model predictive control thus fully leverages modern CNC machines’ dynamic ranges while optimally compensating for disturbances through real-time dynamic models of relevant mechanical properties. Modern industrial computers readily handle increased computational loads from model predictive control algorithms as implemented by PROBOT. This approach has been implemented for a Bystronic ByStar Fiber gantry-type laser cutting machine, where three axes are controlled using PROBOT implemented on a high-performance control system (e.g. Beckhoff TwinCAT3).
RESULTS
A high precision cross grid measurement system was utilized to rigorously assess tool center point motion accuracy. This metrology equipment is capable of contour analysis with micrometer resolution, allowing for precise evaluation of machine tool contour tracking precision both with and without PROBOT engaged. A test workpiece incorporating an assortment of demanding contours, such as tight corners and small features, was machined to thoroughly test the controller’s performance. The results demonstrated PROBOT’s ability to deliver vastly improved tracking accuracy across all assessed tolerance thresholds. Most notably, the model predictive control approach, which is available by our PROBOT library, reduced the worst-case deviation between the tool center point and the target geometry by 49% compared to the machine’s baseline capabilities. This significant enhancement represents a major improvement poised for wider integration into additional CNC machine platforms through open automation environments like TwinCAT3 that facilitate third-party software integration. The quantitative performance evaluation signifies PROBOT’s potential to enhance precision and reduce dimensional variation for precision manufacturing applications requiring micrometer-level tolerances.
ADVANCED MOTION PLANNING FOR CNC machines: Redundant Axis
PROBLEM
CNC machines need to produce small lot sizes with increasingly higher demands on the speed while achieving very high quality for the produced part. For laser cutting machines for instance the realizable cycle time is a major KPI. PROBOT fully exploits the system capabilities to offer the best speed and quality for each individual part that is cut. CNC machines can be significantly improved by the application of PROBOT.
SOLUTION
In this use case, the PROBOT software has been successfully integrated into the CADCAM system of the laser cutting machine. The CNC machine features two redundant axes for the cutting movement. They differ in terms of speed and range of motion. The PROBOT software is used to split the cutting motion time-optimally on the two axes. As a result, the best cutting plan is generated for each individual part that is cut.
RESULTS
PROBOT significantly improves the cutting process. For typical cutting plans the cycle-time is reduced by 10%, while achieving same level of precision of the produced parts. At the same time, the maximum excitation, which corresponds to the vibrational load of the machine, is reduced by 50% for the heavy axis. PROBOT gives the CNC manufacturer a competitive advantage for their machines.
Industrial Robots
PROBLEM
The motion planning for industrial robots is a complex, time consuming task. This is especially true for applications with movements where several requirements must be fulfilled at the same time. Typical examples include grinding, polishing, and welding. In these cases, a collision-free movement needs to be found while there are requirements on the end-effector, e.g., constant speed of the tool movement.
SOLUTION
In the video shown, PROBOT has been successfully applied for automatic motion planning of an industrial robot. By using PROBOT, the brand-specific robot program can be generated with drastically reduced programming efforts. No expert knowledge is needed to develop complex applications. The entire scenario is set up offline with CAD files. Based on this scenario the optimal robot program is calculated by PROBOT.
RESULTS
In this demonstration PROBOT generates a Stäubli robot program. The generated movement tracks the linear path with constant end-effector velocity. At the same time the orientation of the robot is adjusted on-the-fly to avoid collisions with the obstacles. Due to the PROBOT-based workflow, the robot program can be instantaneously adjusted for modified scenarios
Autonomous Vehicle Charging
Solution Tech Features
- Vision based car pose estimation
- Force-feedback based plugging
- Multi-vehicle charging capability
- Opening/Closing of charging lid
High Adaptability
- No vehicle modifications required
- Supports all common connector standards *
- Car-model specific charging strategy
- Suitable for indoors/outdoors operation
Technical Readiness
- TRL 7 (System prototype demonstration in operational environment)
- Successfully deployed at BMW within autonomous valet parking demonstration including automated parking, charging, washing of cars
- Integrated into fleet management system to autonomously receive plug requests
- Easy to install and set up (only 15 mins of training required)
- Robust plugging of any vehicle type/configuration
Looking for more information?
If you’d like to find out more about PROBOT, let us know. Either use the webform on the right or book a meeting via the link below. Our team of experts will be happy to discuss more details with you.