The use of servomotors in AGVs

Automated guided vehicles (AGVs) are increasingly used in internal logistics applications to digitize, automate and streamline various processes. Battery-powered vehicles require energy-efficient drives that can be built into a compact space. They must also meet high requirements in terms of performance and dynamics. When developing suitable drive solutions for such applications, Groschopp's specialists continuously push the boundaries of what is physically possible.

AGVs can transport goods or materials within production, storage or logistics processes without human intervention. Indeed, they are controlled using intelligent network technologies. "In internal transport, such battery-powered vehicles are mainly used to increase efficiency," says Aleksandar Andric, head of the electronics R&D department at Groschopp. The available installation space in such vehicles is often limited and high demands are made in terms of dynamics and performance. This presents challenges for manufacturers of low-voltage servomotors. Andric continues, "The use of batteries also raises the importance of energy efficiency. The longer a transport robot can operate in a production environment without recharging, the better." They must also be equipped with safety brakes so that the AGVs can stop reliably if obstacles or people suddenly get in the way.

Decades of experience in low voltage systems

Groschopp has been developing and manufacturing compact and robust low voltage servomotors from 24 V to a maximum of 60 V for more than 30 years. The German manufacturer with exclusive Benelux representation in Hardinxveld-Giessendam can safely be considered one of the pioneers in this market segment. "In servomotors for the pharmaceutical and food industry, we were already applying a very low safety voltage," indicates Aleksander Andric. "That allowed us to gain the necessary experience to develop and produce energy-efficient low voltage servomotors." Thanks to this expertise, today the manufacturer manages to develop solutions for the most diverse sectors, including for applications with AGVs where very high requirements are required.

Despite their compact design and high energy efficiency, low-voltage EGK servo motors are extremely powerful and dynamic. "Actually, these are contradictory design goals," Andric explains. "To still meet these, we pursue a very high standard and always push the limits of what is physically possible when developing our drive solutions." The EGK series from the Black Panther family includes the third generation of servomotors with electric commutation. The performance and efficiency of these servomotors have been significantly increased by the continuous optimization of the active core components stator, rotor and magnets and the use of a very modern winding technique, called "Einzelzahnwicklung" or "single tooth winding. In this technique, the motor's coils are not wound on the entire circumference of the stator, but on individual teeth of the rotor. Thus, each coil concentrates on one tooth of the rotor, providing high accuracy, high power density and more efficient energy transfer. Compared to block commutation, the optionally realizable sine commutation provides higher efficiency, very good synchronization characteristics, especially at low speeds, and less noise and heat generation.

Energy efficiency is one aspect, but safety also plays a very important role in these AGVs to prevent incidents and damage. For this purpose, the manufacturer offers servomotors with low voltage and electrical commutation as well as corresponding safety brakes. "For example, there are redundant encoder systems with two separate encoders that control each other and meet high performance levels," explains Andric. "We are compatible with systems from different manufacturers and also offer our own solutions." Groschopp's smart servomotors come standard with a CAN interface for data transfer. Optionally, they are also available with Profinet or Ethercat.

Modular construction

With the EGK series, the drive specialist can provide a comprehensive, modular product portfolio of servomotors in different sizes with and without inverters and with different types of gearboxes, which can be tailored precisely to the requirements of each application. "Our low-voltage servomotors are ideal for use in battery-powered transport robots," says Andric. "We are constantly investing in the further development of our products so that we always offer the latest in terms of technology." The in-house R&D department is the cornerstone for success in the field of drive solutions. It has state-of-the-art equipment, a specially equipped prototyping center and its own laboratory. To create new products or customized concepts, a team of highly qualified employees from different disciplines work closely together: from development and design to production, product management and sales. Groschopp also collaborates with universities and partner companies on projects to promote the development of innovative and economical drives in the field of electromobility and AGVs. Thus, the specialists also know which research projects are ongoing.

For example, a project in which students at the Technical University of Novi Sad in Serbia developed an autonomous robot that recognizes waste and also disposes of it automatically. This intelligent robot is powered by Groschopp's EGK 48-60 low-voltage servo motors combined with a worm gearbox and integrated servo controller. This enables smooth movements and precise positioning. Moreover, the drive solution can be adapted to any application thanks to the freely programmable software and the many options in terms of electronics and design.

Custom drive solution

Groschopp produces motors in small and medium quantities as well as in larger series. The specialists from Viersen also realize special designs or use special materials to provide solutions specifically tailored to customer requirements. For the production of the components of these drives, the manufacturer uses state-of-the-art machinery and automated production lines. For motors with electric commutation, production includes a fully automated winding line, for all other motors fully automated production lines for pole coils and armature winding. This ensures efficient and fast production and a high degree of flexibility for special requirements. "We offer customized solutions that implement the maximum technically and economically feasible from the application," concludes Aleksander Andric. "Moreover, the motors are precisely tailored to the particular application in terms of speed and efficiency." Durability also plays an important role at Groschopp: the drives are characterized by high quality and are extremely wear-resistant and durable even at high loads.