PCB DESIGN OF A SERVO MOTOR CONTROLLER UNDER STRICT COST CONSTRAINS – PI AWARE DESIGN

Abstract

This work comes within the scope of developing an automated linear axis that will be used in a novel production machine. The axis needs precise control over the linear movement, calling for a servo-controlled motor. There are many types of motors that can be used, starting from inexpensive stepper motors, up to expensive and performant multi pole permanent magnet synchronous motors. The project calls for a servo drive that will be able to deliver a power output within 200 to 600 Watts, with an efficiency of over 80%. Brushless DC motors offer many possibilities within this range of powers with outstanding price/performance ratios. Open source projects like TinyMovr, Vesc and ODrive propose highly performant software stacks that are used extensively within robotics communities. These open software solutions need adequate hardware platforms to perform. The scope of this work is the description of the steps taken to design the printed circuit boardon which the ODrive servo motor control firmware can be implemented, from the point of view of the power integrity of its energy supply means. Under normal cost constrains, the PCB would have been implemented using a minimum of four copper layers. It is the aim of this design to fulfil a stricter cost constrain that only allows for a two layer board to be used.