For autonomous vehicles

An important requirement in vehicles is the safe detection of angles and speeds - for example in autonomous industrial trucks. This is made possible by functionally safe and certified encoders with a suitable safety interface on rotary axes or drive motors. With the safe data 'position and speed', the autonomously moving vehicles can quickly approach their target positions. Monitoring with compact encoders serves to protect the environment, people and machines.

Certified safety sensor technology in a small design is particularly required in the autonomous driving vehicle sector. In particular, 'Automated Guided Vehicles' (AGV) and 'Autonomous Mobile Robots' (AMR) should be mentioned here. AMRs are more adaptable to the current work situation due to their more flexible navigation without lane and route specifications and further infrastructure. They can adapt their routes according to the situation and often realise more efficient logistics. It is precisely here that powerful sensor technology is important in order to achieve safe operation. The steering angle, the wheel speed and the position of any implements must be reliably available at all times.

Since space and weight have to be saved in the agile and compact systems, small and lightweight safety sensors are in demand. For this application, TWK provides a portfolio of certified sensors in compact design with different safety interfaces: For example, single-turn encoders with a housing diameter and length of only 38 mm with a Fail-Safe-over-EtherCAT (FSoE) interface (TRK38) or devices with a housing depth of only 30 mm and CANopen safety interface with a diameter of 55 mm (TBN55). These and other safety interfaces, such as PROFIsafe via PROFINET, are available in various enclosure designs. Versions with the proven multiturn gearbox are available from 42 mm diameter.

The miniature encoders can be placed directly on the wheels of automated guided vehicles to detect the travel speed. Or they can be placed on the drive motor. For this purpose, there are versions in housings made of magnetically shielding stainless steel. They can process speeds of up to 15,000 rpm and have a typical position resolution of 16 bits/360°.

Small versions of encoders are also used to detect the steering angle of the vehicle. Here, too, measurements can be taken at the wheels or, after an intermediate transmission gear, at the servomotor. In the latter case, TWK offers devices with SIL2-certified software - called turntable software - which reliably converts the position of the motor/sensor shaft position to the position of the wheels (steering angle) - even if the vehicle is turned as far as desired in one direction and the measuring range is thus completely traversed. Even when the encoder is switched off, the shaft can complete at least 1024 revolutions. After switching on again, the wheel position is output reliably and correctly. During commissioning, the user transmits the transmission ratio of the gearbox and the desired resolution as parameters via the encoder's interface and can start.

All units are certified according to IEC 61508 and/or ISO 13849 - with level SIL2 or PLd. Further units are available with SIL3 certification. In addition, TWK offers certificates for UL, E1 type approval, ATEX/IECEx and fully redundant sensors (R2).