Abstract

The paper describes the application of a non-contact, high bandwidth, low cost, SAW-based torque
measuring system for improving the dynamic performance
of industrial process motor-drive systems. Background to
the SAW technology and its motor integration is discussed
and a resonance ratio control (RRC) technique for the
coordinated motion control of multi-inertia mechanical
systems, based on the measurement of shaft torque via a
SAW-based torque sensor is proposed. Furthermore, a
new controller structure, RRC plus disturbance feedback
is proposed, which enables the controller to be designed to
independently satisfy tracking and regulation
performance. A tuning method for the RRC structure is
given based on the ITAE index, normalized as a function of
the mechanical parameters enabling a direct performance
comparison between a basic proportional and integral (PI)
controller. The use of a reduced-order state observer is
presented to provide a dynamic estimate of the load-side
disturbance torque for a multi-inertia mechanical system,
with an appraisal of the composite closed-loop dynamics.
The control structures are experimentally validated and
demonstrate significant improvement in dynamic tracking
performance, whilst additionally rejecting periodic load
side disturbances, a feature previously unrealisable except
by other, high-gain control schemes that impose small
stability margins.