industrial//industrial automation//motion control

Motion control is the branch of automation that drives several axes so that they behave as one coordinated mechanical system rather than as independent motors A, B and C, and it is what CNC machines and multi-axis robots run on. For a tool to follow a curve, \(X(t)\), \(Y(t)\) and \(Z(t)\) must be synchronized with great precision.

Motion control is the branch of automation that drives several axes so that they behave as one coordinated mechanical system rather than as independent motors A, B and C, and it is what CNC machines and multi-axis robots run on. For a tool to follow a curve, X(t)X(t)X(t), Y(t)Y(t)Y(t) and Z(t)Z(t)Z(t) must be synchronized with great precision.

It is the most demanding timing regime in the plant: fast, and also synchronized to the microsecond across nodes. Discrete automation asks whether an event happened in time; motion control asks whether five axes were at the right place at the same microsecond, and needs a clock the first can ignore. That is why networks built for motion, above all EtherCAT, are described as hyper-deterministic, and why PLC scan cycles of milliseconds are not enough on their own.

Each axis is closed by a servo drive (drive); the motion controller distributes setpoints to all of them on a common clock. A robot controller is a motion controller specialized for an arm.