A novel linear actuator using a low cost BLDC motor with integrated stall detection

The use of stepper and brushless permanent magnet motors in a wide range of applications is constantly growing, thanks to great improvements in permanent magnets, as well as in power electronics. These improvements encompass increasing performance as well as steady cost reductions. There is an increasing need for linear actuation in a wide range of applications. Conventional solutions used are: stepper motors with a leadscrew; and solenoid with direct drive actuation. With respectively the following drawbacks: difficult fail safe operation (stepper); and a complicated closed loop control (solenoid). We present in this paper a BLDC motor design associated to a linear motion transformation, this BLDC motor can be used as a brushless DC motor with closed-loop control using low-cost Hall probes or by detection of the back-EMF. We also present a stall detection process for stepper motors.