27/10/2011

Gearhead design for delta robots by WITTENSTEIN

With its deep-rooted engineering know-how, acknowledged methodological and software expertise and impressive portfolio of high-performance products, WITTENSTEIN creates transmission and actuator solutions with unbeatable specifications. In virtually every instance, significant performance reserves that are not revealed simply by studying the technical data in the catalogue can be leveraged as a consequence of direct contact with customers and their applications.

Delta robots tend to be unique - with big implications for the drives

WITTENSTEIN has been designing transmission and actuator solutions for delta robots for almost a decade. Their diversity is enormous - hardly any two robots are alike. The handling tasks presented for evaluation call for robots with two, three or sometimes four axes, the products and product weights vary, the pick & place distances differ from one facility to the next and so on. The challenges almost invariably involve very high cycle numbers and short, highly dynamic motions in a high duty cycle. Account must also be taken of the place of installation and the mounting position of the gearheads and actuators, especially in food processing applications. The individual axis drives are subjected to manifold operating loads, and superimposed tilting moments and torques often act on the output. At the same time, absolute reliability is essential because the majority of delta robots are located at the end of a product's value chain, for example on a confectionery packaging line. WITTENSTEIN's engineering experience offers ample confirmation that the transmission and actuator solutions are as individual as the delta robots themselves.

From the point of view of the drive technology, in other words, there is no such thing as a standard application for delta robots. As a result, choosing a transmission or actuator solution "off the peg" is bound to be suboptimal in terms of the delta robot's performance, flexibility, stability and availability. On the other hand, by resorting to WITTENSTEIN's vast expertise and taking advantage of its know-how, customers acquire an effective guarantee that each delta robot will be pushed to its performance limits - a precondition of maximum efficiency in the end user's production environment.

The first step in designing a drive solution for delta robots is to analyze the task at hand in the context of any general conditions and constraints. Initial, theoretical calculations are performed on this basis in order to map the multidimensional motions in space and determine interactions with other moving components of the robot. Real torques, load data and potential dynamic effects, for instance if the drive system begins to vibrate, are then calculated in detail and optimized with the help of a so-called multibody simulation. It is also important at this stage to identify what are referred to as overload factors and exploit them to achieve extended design and application areas or greater energy efficiency as well as to downsize the delta robot's entire drive train. The technically controllable power reserves that are tapped in this way frequently go far beyond the product-specific data contained in the catalogue.

Source: WITTENSTEIN AG