High force density actuators with inherent safety

Abstract:
Electrification is a huge trend nowadays which can be found in a lot of markets, e.g. automotive, aviation as well as automation. The motivation is to get rid of hydraulic and especially pneumatic actuators due to its low efficiency of about 19%. For power ranges from several hundred watts up to the kilowatt range, electromagnetic or electrohydraulic drives are well suited to fulfil these requirements. However, the electrification of drives for low power applications with high forces is a big challenge, especially when it has to fit in the same or even a smaller design space. For this reason, small electromagnetic actuators are combined with high ratio gears like spindles. However, these drives have a self-locking behaviour which causes troubles when customers need another safe condition in case of failure. Furthermore, such electromagnetic actuators need much more power and therefore energy to fulfil such requirements, when the maximum force and speed is not needed at the same time. Besides, small spindle drives are usually sensitive to greater overload, e.g. in the event of unintentional collisions.