High-Performance Sensors for Industrial Robotics
Sensors play a key role in the use of robots in industrial processes. They enable robots to perceive their surroundings, position themselves accurately, and carry out work steps precisely.
Also read: OWR opens Europe's first robotics demonstration centre
Precision Sensor Technology for Robot Calibration
Micro-Epsilon sensors are already being used in the calibration of robot axes. To achieve fully automatic, independent calibration of robot cells, scanCONTROL laser scanners and optoNCDT laser triangulation sensors are utilised. These optical sensors enable continuous monitoring and restoration of the production process at the push of a button. The sensors are placed directly on the robot and measure onto a plate with reference targets. This system operates with special software from teconsult, allowing for the direct integration of various Micro-Epsilon sensors. Additionally, the solution can perform automated measurements, tests, or corrections of robot kinematics, robot grippers, and the periphery of the robot cell. The sensor technology is permanently integrated into the robot cell or used as a portable service tool.
3D Scanning Sensors for Laser Cladding in Robotics
In laser cladding, a melt pool is created on the surface of the component, and a new, pore-free layer is formed by adding a powdered filler material. The core task of the sensors is to detect free forms and shape deviations before laser processing. A laser scanner from Micro-Epsilon's scanCONTROL series scans the components, potentially from several directions depending on the component geometry. Regardless of the material's reflection properties, the sensor consistently provides reliable measurement values. The raw data is directly transferred to the customer’s software, merged into a 3D model, and used for the path planning of the laser welding head. This ensures that the nozzle is placed at the correct distance from the surface and guided accurately along the calculated path, resulting in a smooth and even surface. Compared to camera solutions, laser profile scanners are surface-independent in terms of contrast, offering higher precision and various integration possibilities, with significantly shorter cycle times for non-contact measurement.
Laser Scanners for Concrete Printing Process Control
Micro-Epsilon laser profile scanners are used for process control in concrete printing. These compact and lightweight scanners can be mounted directly on a robot to measure the concrete strand immediately after application. Thanks to large measuring ranges and integrated signal calculation and evaluation, the complete strand is measured quickly and precisely. The evaluated measurement signal is transmitted directly to the control system, ensuring accurate print head positioning and consistent concrete application.
Laser Line Sensors for Windshield Installation in Automotive Manufacturing
In the automotive industry, certain measurement tasks require simultaneous detection of several values or three-dimensional detection of objects within short cycle times. For instance, during vehicle windshield installation, a scanCONTROL laser line sensor detects detailed distance values across all axes. The sensor is mounted onto the robot that installs the windshield, detecting the complete profile and vicinity of the windshield in a single, quick run. This allows for immediate assessment of whether the windshield is placed straight, centred, and fits perfectly in every plane. The results, such as gap and flushness, are directly generated in the sensor head and output to the PLC.
Real-Time Quality Control with Laser Scanners for Adhesive Bead Inspection
Another critical task involves inspecting the adhesive applied before the windshield is fitted into the chassis. A laser scanner mounted onto the robot applies the adhesive beading and moves along the bead to create a 3D image. This inspection determines if the adhesive quantity is sufficient, evenly applied, and correctly placed. All detected measurement values are stored separately, allowing for later analysis if an error occurs during the process.
Blue Laser Technology for Challenging Industrial Materials
The strengths of the scanCONTROL laser scanners and optoNCDT laser triangulation sensors lie in their compact design, enabling easy integration into robot-based applications, even where space is limited. These sensors are equipped with robust cabling, making them suitable for the extreme rotational and torsional movements on a robot arm. The integrated, highly sensitive receiver matrix allows for measurements on almost all industrial materials, largely independent of surface reflection. Real-time quality control enables immediate intervention in production processes.
Micro-Epsilon offers sensors with red laser diodes and the patented Blue Laser Technology, which is used when red laser light reaches its limits. This is particularly useful for organic materials, wood, semi-transparent materials, or red-hot glowing metals, where blue laser light can be focused more sharply to achieve high precision measurements. For applications in harsh environments, Micro-Epsilon provides special accessories, such as protective housings with interchangeable screens and compressed-air purge systems to protect optical components from dust.
Understanding the Measuring Principles of Laser Sensors
Measuring Principle of Laser Profile Scanners
The laser profile scanner uses the triangulation principle for two-dimensional profile acquisition. It emits a laser beam that is expanded into a laser line, which then hits the measuring object. The laser light is reflected by the object's surface and projected onto a highly sensitive receiving matrix in the sensor. Besides distance information (z-axis), the controller also calculates the position along the laser line (x-axis) using this camera image. These measured values are then output in a two-dimensional coordinate system fixed with respect to the sensor. When dealing with moving objects or a traversing sensor, it's possible to obtain 3D measurement values.
Measuring Principle of Laser Triangulation Sensors
The laser triangulation principle is based on a simple geometric relationship. A laser diode transmits the laser beam onto the measuring object, and a lens focuses the reflected rays onto a CCD/CMOS array. The distance to the target object is determined using a triangular relationship between the laser diode, the measurement point on the object, and the image on the CCD line. The measurement resolution can reach a fraction of a micrometer.
