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.
Engineers torque technology to medics
Medical experts and sports scientists are becoming increasingly reliant on engineers as their disciplines become more and more technical. Mark Ingham looks at some of the projects his company, Sensor Technology, has helped behind the scenes.Like most rugby players I took my knees for granted until the day a twisting fall resulted in a torn anterior cruciate ligament. Fortunately these days it can be fixed with surgery and nine months of physiotherapy, but I took some comfort in the fact that Sensor Technology has...
Providing the Key to Learning
The electrical machines laboratory at the Dublin Institute of Technology (DIT) has greatly increased in its effectiveness as a teaching resource since TorqSense non-contact torque sensors from Sensor Technology have been fitted to five machine sets. The new sensors replace an existing system of machine monitoring that had proved inaccurate.
Torque about improving handling accuracy
Dry bulk handling is en route to becoming a precision science with a level of control previously undreamt of, thanks to 20 years of research and development into digital non-contact torque monitoring. Dry bulk handling is following many other industrial processes that have been redeveloped from a ‘black art’ to a highly accurate and controlled procedure. A generation ago much of industry was in the hands of time-served artisans who relied on their many years experience to tweak and tease operations to ensure a...
Dynamic rotary torque measurement using surface acoustic waves
The subject of torque measurement has previously been addressed extensively. Most of the existing transducers either rely on low voltage analogue systems (e.g. conventional resistive strain gauge) or complicated mechanical assemblies by physically assessing displacement, i.e. optical systems. This paper identifies a new, potentially low cost, non-contact, frequency domain strain torque sensor1 utilising SAW (Surface Acoustic Wave) Technology for surface strain measurement. The sensor has a short axial length...
Case study - REDWAVE XRF - State-of-the-art technology for ore mining
Here, ore mining began in the fourth century - a date which is supported by remains of melting furnaces found in the small Styrian town called Eisenerz (the German word for iron ore). The name could not be more characteristic. The reddish terraces of the Erzberg, the largest open cast mine of Central Europe and, at the same time, the largest siderite deposit worldwide, are widely visible.It is estimated that since the beginning of the records, about 255 million tons of iron ore have been mined. The annual hewing...