- Mobile Robots
- Safe Motion Control
Safely steered to the destination: Powerful controllers and safety solutions for mobile robots
Detailed view of motion control products
Safety is paramount when mobile robots interact with their human counterparts. As the central command unit, the controller has a special role to play here: It must ensure that the mobile robot is reliably brought into a safe operating state in the event of an emergency. To do this, the controller must faithfully process the information from the safety sensors and issue appropriate commands to the safety actuators. Relevant safety sensors include, for example, safety encoders that continuously monitor the rotational speed of the mobile robot’s wheels or the position and speed of movement of the forklift tines.
Safety controllers ensure that these safety-relevant actions are carried out and that the mobile robot does not leave the safe state until the hazardous situation has been resolved. In order to ensure the long-term reliability of the interaction of all devices involved in personnel safety, increased effort is often required during the integration phase to program the control software. Depending on national regulations, the safety behaviour of this software must also be tested and confirmed by external experts.
Implementation of a safety-related robot control system
Problem
Programming control software from a safety perspective is much more complex than non safety-related software, and the development costs increase enormously.
Solution
With the compact ecomatBasic controller, ifm offers a solution especially for mobile robots that combines a standard PLC and a safety controller in one device. The safety-related control software can be programmed using a library of function blocks prepared by ifm. This reduces the programming time considerably. As this library is already TÜV-certified, it may, under certain conditions, then be possible to dispense with another inspection by an external expert.
Problem
In addition to the safety controller, a standard controller needs to be integrated into the mobile robot to ensure that all processes run efficiently and safely. This adds cost and requires additional installation space.
Solution
ifm’s safety controllers have both a safety controller and an independently operating standard controller. This means that all processes of a mobile robot can be mapped via one control unit. The result is a reduction in costs and required installation space.
Problem
Integrating safety sensors from different manufacturers is usually only possible with additional software interfaces, which adds to the programming effort, code size and complexity.
Solution
The certified CIP Safety Interface software is integrated in our compact ecomatBasic controller. This allows, for example, the integration of certain safety lidar sensors with full functionality without third-party software. As a result, the programming effort and code size are significantly reduced.
Problem
In order to safely monitor the rotation of wheels or moving superstructures, redundant systems had to be used in the past, which then had to be tested and certified.
Solution
ifm’s safety encoders have an internal redundant system. What is more, they are already certified as safe. This reduces the user’s design time, the required installation space and the costs for certification.
Problem
If the position of a mobile robot is monitored via the rotational movement of the wheels, slip, for example, can lead to inaccuracies in the position monitoring.
Solution
An additional RFID antenna can be used, for example via RFID tags embedded in the floor, to synchronise the position without interrupting operation, in a so-called "preset on the fly” process. The safety encoders accept the corrected data and positioning inaccuracies are eliminated.
Benefits of the ifm safety controllers
- Simple spatial integration
The ecomatBasic safety controller is designed for use in confined spaces. It is robust and insensitive to vibrations. This makes the ecomatBasic ideal for mobile robots.
- Easy to use and versatile
A large memory, freely configurable inputs and outputs as well as CAN and Ethernet interfaces maximise performance and flexibility.
