PDC sensor for collision protection
An ultrasonic sensor for collision protection is a non-contact device used to detect obstacles, people, or objects in the path of automated guided vehicles (AGVs), robots, and mobile equipment to prevent collisions. These sensors provide reliable detection regardless of surface structure, material, or environmental conditions, enabling automatic braking or evasive action. This guide covers the operating principles, safety standards, and applications of ultrasonic sensors for collision protection.
An ultrasonic sensor for collision protection is a non-contact device specifically designed to detect obstacles, people, or objects in the path of automated guided vehicles (AGVs), autonomous mobile robots (AMRs), and other mobile equipment to prevent collisions and ensure safe operation. When moving materials using AGVs, all directions of travel must be reliably protected to keep personnel and objects in the lane safe from collisions. The sensor used for collision protection must not only reliably detect obstacles but also output the corresponding signal quickly enough that the self-driving robot can brake or change direction in time. Ultrasonic sensors are ideal for this purpose because obstacle detection works independently of the obstacle's surface structure and is unaffected by dirt build-up or environmental and weather conditions. The USi-safety ultrasonic sensor system is the only safe ultrasonic sensor system according to EN ISO 13849 category 3 PL d, enabling reliable monitoring of three-dimensional spaces.
PDC Sensor
The operating principle of an ultrasonic collision protection sensor is based on the time-of-flight measurement of sound waves. The sensor emits high-frequency ultrasonic pulses toward the monitored area. When an obstacle, person, or object enters the detection zone, the sound waves reflect off the target and return to the sensor. The sensor measures the time taken for the echo to return and calculates the distance to the object. If an object is detected within the safety zone, the sensor sends a signal to the vehicle's control system, which initiates braking or evasive action. The USi-safety system features an elliptical sound field with an opening angle of ±17° and ±5°, optimized for monitoring a 3-D range. The sensor units are extremely small and can be freely positioned, even in the narrow space of fork arms. The detection range can be quickly and easily adapted to conditions via parameterization software.
Ultrasonic sensors offer significant advantages for collision protection applications. They are insensitive to weather conditions, visual irritation, and dirt. They detect objects regardless of the material or surface. Unlike laser scanners, ultrasonic sensors can detect obstacles that hang from above into the lane or are raised off the ground. The sensors are resistant to environmental influences such as dust, dirt, air currents, humidity, and similar factors. If multiple USi-safety systems are installed on several independent AGVs that cross each other's paths, mutual interference suppression prevents them from interfering with each other's function. The sensors feature a teach-in function for teaching in the complete detection area, suppressing vehicle contours that could cause disturbances. The sensors are also resistant to moisture and can be used in exposed areas without problems. This combination of robustness and reliability makes ultrasonic sensors ideal for collision protection in demanding industrial environments.
The applications of ultrasonic collision protection sensors are extensive across mobile equipment and automation. In AGVs and AMRs, the sensors provide reliable protection in all directions of travel. At least one protection measure to PL d is required in the main direction of travel (forward), and at least one to PL c in secondary directions (sideways and reverse). For load transfers with loaded pallets, protection to PL d is needed for automatic reverse travel. The USi-safety system can detect people and objects in the area around the sides of the vehicle. In robotics, ultrasonic sensors provide collision protection between robots and environmental objects. In port logistics, ultrasonic sensors on reach stackers ensure precise distance measurement between the picker and the container, automatically reducing speed to avoid collisions. The sensors are also used in aviation for collision protection between aircraft and baggage conveyor vehicles. The USi-industry sensor system is used for environment detection on material handling equipment as collision protection, area monitoring, and as an assistance system on warehouse picking devices.
The safety standards and certifications for ultrasonic collision protection sensors ensure reliable and fail-safe operation. The USi-safety system is certified according to EN ISO 13849 category 3 PL d. The control interface offers two safe OSSD outputs per channel for the adjustable protection field and one PNP switching output for the warning field. The sensor units comply with IP69K protection, and the control interface complies with IP65. The reaction time is typically 99 ms, ensuring rapid response to detected obstacles. The sensors operate in temperatures from -30°C to +50°C. The sensing range is up to 2,500 mm. High-resolution sensors with 1 mm precision are available for applications requiring very accurate distance measurement. These comprehensive safety features ensure that ultrasonic collision protection sensors provide reliable protection for personnel and equipment in the most demanding industrial and logistics environments, enabling the safe operation of automated guided vehicles, robots, and other mobile equipment.
