"We were looking for a suitable provider of planetary gearboxes that were exactly right for our system or can be adapted accordingly - and we also wanted them to be manufactured in Germany."
M. Eng. Manuel Frey | Head of Development | fruitcore robotics GmbH
An industrial robot that is easy to operate, powerful and also reasonably priced - German robot manufacturer fruitcore robotics is making things happen on the robotics market with this seemingly simple business idea. This extraordinary price/performance ratio is made possible by means of intelligent technical details. This also includes the new kind of drive concept of the robot, which combines four-unit linkages and planetary gearboxes from Neugart.
Constance-based fruitcore robotics GmbH specializes in the development, manufacture and marketing of technically excellent and easy to operate industrial robots. The focus is on having a self-developed system which makes automation easy for companies of any size. Established in 2017, the fledgling company now has about 50 employees, including highly specialized experts for construction, electronics and software development.
The modular portfolio includes the HORST (the name stands for Highly Optimized Robotic Systems Technology) industrial robot, the intuitively operated horstFX software, and also suitable accessories such as grippers and a mobile robot base. The 6-axis industrial robot with a reach of 905 mm, a payload of up to 5 kg and repeat accuracy of +/- 0.05 mm is based on a new type of drive concept with four-unit linkages which is completely new in the field of robotics. By dispensing with the cost-intensive shaft or cycloid gearboxes that are normally used, HORST provides an optimum ratio of reach and payload and a comparatively low price.
Four-unit linkages have a non-linear and therefore position-dependent transmission ratio. Manuel Frey, co-founder and development manager of fruitcore robotics, explains exactly what this means with regard to a robot arm: "because of the high transmission ratio of the four-unit linkage when the arm is extended, the torque peak which would be applied to accelerate this extended arm including the load is significantly less than with conventional robots."
The advantage of this is that smaller motors can be used, which reduces the price of the robot. However, during the course of the development work, it was discovered that the ratio of the 4-unit linkage alone was insufficient. For this reason, additional gearboxes are used on the axes as the solution. This combination is what makes HORST unique.
Single-stage planetary gearboxes proved to be the optimum gearbox type for this special application. In order to ensure that the optimum payload and reach are achieved with the highly dynamic robot movements, the entire drivetrain must be efficiently designed. The correct transmission ratio acts as a basis for this, and is largely determined by the planetary gearbox. "Without the four-unit linkages, in theory we would have had to use two-stage gearboxes, which have higher torsional backlash and would therefore be a disadvantage in articulated robots", says Manuel Frey, describing the less practicable alternative.
A suitable manufacturer was not easy to find for the people in charge at fruitcore robotics, as Manuel Frey recalls: "It took us a long time to find a suitable provider of planetary gearboxes that were exactly right for our system or can be adapted accordingly - and we also wanted them to be manufactured in Germany." Against this background, the company chose gearbox specialist Neugart from Kippenheim, in Baden-Württemberg.
The most important criterion for development manager Manuel Frey and his colleagues was having gearboxes with high precision and very low torsional backlash. The endurance strength of the gearboxes and a long robot service life are also ensured by operating within the nominal range.
Four Neugart planetary gearboxes of different sizes are used on the six robot axes. These are extremely light, powerful and also suitable for demanding, dynamic load cycles due to their low-friction bearing concept and optimized lubrication.
As well as the product characteristics, the fact that the collaboration ran smoothly also spoke in favor of Neugart: "The implementation of the gearboxes was absolutely problem-free", confirms Manuel Frey. "Neugart always reacted to our adaptation requests quickly during the development phase. The data and information in the catalogue and the TDF and NCP configuration tools which Neugart provided right from the start were also very useful, and so comprehensive that we were able to start immediately. Of course, technical issues cropped up occasionally, but these were always quickly and easily cleared up with close reciprocal coordination."
From the point of view of fruitcore robotics, the fact that the manufacturer is already prepared for future requirements with its extensive portfolio spoke in favor of Neugart as a supplier: "Other robot sizes are in the pipeline", says Manuel Frey, looking towards the future. "Because of the wide range of gearbox models that are available, nothing stands in the way of this plan - and the continuation of our successful collaboration with Neugart."