Object detection and position determination in 2D

Object detection and position determination in 2D

• Jonas Ledergerber, Product Manager for LiDAR sensors, SICK AG, Reute

Is a surface empty or is a shelf occupied? Where is a specific object and how far away is an obstacle? The 2D LiDAR sensors from SICK’s TiM product range can provide answers to questions like these which often arise in the context of industrial and intralogistics automation systems. There are three product families available, each designed and equipped for different detection and measurement tasks. The innovative HDDM scanning technology that they use guarantees the highest levels of detection reliability and functional safety for every type of application.

Each of the three LiDAR product families – TiM1xx, TiM3xx and TiM5xx – (LiDAR stands for Light Detection And Ranging) has its own specific strengths in surface monitoring. They are compact in size. For example, the maximum housing height of the TiM5xx is only 86 millimeters. They are also light in weight. For example, the TiM100 weighs just 90 grams. Both of these features, combined with their easily assembled and highly functional mounting system and simple setup process, highlight the quality of their industry-standard design. As a result, the TiM sensors can be easily integrated into stationary and mobile applications and into robots and moving machine components.

Innovative HDDM scanning technology for high precision and availability

The 2D LiDAR sensors of the TiM product families all use infrared light from laser class 1, which causes no damage to eyesight, and the innovative HDDM technology (High Definition Distance Measurement) developed and patented by SICK. This is a high-resolution digital process for measuring time and distance which sends out more than 100 times as many laser pulses as other time-of-flight measurement systems. The distance to the object is calculated on the basis of the time-of-flight measurement and an evaluation of the signal strength. The time between a laser pulse being sent out and the reflections being received is proportional to the distance between the TiM sensor and the object in question. The short sequence of pulses and the low angular resolution in the scan plane of up to 0.33° provided by the TiM3xx and TiM5xx guarantee an uninterrupted scan and reliable detection and measurement functions. The future-proof HDDM measuring process also offers significantly improved optical reliability, for example a high level of ambient light immunity. As a result, it is almost impossible for the TiM sensors to be dazzled either by bright daylight or by high-frequency artificial ambient lighting. The measurement process can also compensate for the effects of dust, dirt and moisture in the environment. The more advanced HDDM+ process used in the TiM100 offers even more reliable and precise measurements. The LiDAR technology of the different TiM series is almost identical, so the question is: which TiM sensor should be used for which type of application?

TiM1xx: the entry-level sensor family for efficient 2D detection

Modest energy consumption of only 2.2 watts, low operating costs, a highly compact design and a weight of just 90 grams make the TiM1xx with HDDM+ the ideal entry-level range for 2D detection. With a aperture angle of 200° and a maximum operating range of three meters, the LiDAR sensor can monitor a surface up to 15.7 square meters in size. One field set is available and the detection zone can be designed and configured to suit the application in question, using either teach-in or software. The field evaluation function is integrated into the sensor. In addition, TiM1xx sensors can be networked using IO-Link. This not only allows them to be set up quickly and easily, but also makes it possible to access status and diagnostics data and to clone the configuration in order to save time if a sensor needs to be replaced. The rotating connector on the already highly compact housing of the TiM1xx offers additional freedom when installing the sensor. The connector not only enables the sensor to be fitted and aligned in different positions, but also ensures that the connecting cable is perfectly positioned within the machine. Machine manufacturers, system integrators and users can carry out complex presence detection tasks with the TiM1xx, which only performs a switching function. These tasks include empty bay detection in pallet and container warehouses, protrusion monitoring for mesh boxes and counting parts as they are removed from a conveyor and placed in containers. Another possible application is monitoring exhibits in a museum. The sensor is an ideal solution in this respect because it can be installed in an unobtrusive location where it is protected from manipulation.

TiM3xx: more functionality, more flexibility and more versatility

The TiM3xx is also designed for mobile and stationary applications, but is fitted with a housing suitable for outdoor use that has an enclosure rating up to IP 67. Its integrated Ethernet interface makes it a high-performance solution for object detection and collision avoidance in logistics and factory automation systems. Within an operating range of up to 10 meters, a variety of different monitoring scenarios can be used over an area of a maximum of 235 square meters as a result of the increase in the aperture angle to 270°. All the sensors in the range have 16 pre-configured field triples in the form of message, warning and stopping fields that cover the most common monitoring applications. The triple field sets can be selected via the inputs which makes installation much easier. One of the triple field sets in the TiM3xx can be configured directly in the sensor to allow for special customized configurations. The micro-USB port used for this purpose is always accessible, even when the sensor has been installed. The individual field shapes can be rectangular, radial or user-defined. The size of the field shapes can be selected quickly and easily by the press of a button using the automated “Touch and Teach” teach-in program. It takes less than two minutes to prepare the TiM3xx for operation. The sensor can also be configured on a PC using the SOPAS software supplied by SICK. The field evaluation function with intelligent software algorithms is integrated into the TiM3xx. Two versions of this LiDAR sensor have “contour as reference” functionality which allows them to monitor themselves for possible misalignment or manipulation attempts. The tried-and-tested HDDM process guarantees high levels of measurement accuracy and ambient light immunity when the system is in operation. The TiM3xx is used, among other things, for distancing and queue control in electrical overhead conveyors and for protrusion monitoring and empty bay detection in storage and retrieval systems. As the power consumption of this SICK LiDAR sensor is low, in mobile applications, such as collision avoidance and reversing protection in driverless industrial trucks or autonomous platforms, it has only a negligible impact on the vehicle’s battery life.

TiM5xx: measurement data output via USB or Ethernet direct to the application

The TiM5xx sensors, which have rugged metal housings with an enclosure rating up to IP 67 for indoor and outdoor use, are the pure measurement devices in SICK’s 2D LiDAR portfolio. They have an even larger monitoring zone covering an area of up to 1,470 square meters with maximum measurement distances of 25 meters. With a possible resolution of 0.33° within a scanning field of 270°, the TiM5xx provides highly accurate measurement data from the scanned surface. This makes it possible to obtain additional information about the size and shape of objects. The sensors in the TiM5xx family do not have an internal measurement evaluation function. Instead they send the data for each individual angle directly to the application in the form of a machine-readable string. Information about the distance of the object, the coordinates and the energy content of the return signal can be sent via the USB port or the Ethernet interface and used for measurement applications such as distancing, object detection or contour detection. The Ethernet interface also supports the implementation process of the TiM5xx, together with diagnostics and remote maintenance functions, while the machine is in operation. An important consideration for mobile applications is that the TiM5xx is one of the most energy-efficient 2D LiDAR sensors on the market, with a power consumption of just four watts.

The 2D LiDAR sensors in the TiM range can be used for a variety of different complex surface monitoring tasks, including reliable object detection and accurate position determination. Their most impressive features include their specialized functionality, ease of integration and energy efficiency.