Fieldbus-linked drive system gives canal restoration project a lift

The combination of Control Techniques' drive and fieldbus technology and Qualter Hall's mechanical design is giving history a 'lift' at the recently opened Standedge Visitor Centre at Marsden, as part of a £30m restoration project on the Huddersfield Narrow Canal.

A CTNet-linked, 4 axis Unidrive system is providing pin-point levels of accuracy and control on a Qualter Hall-designed lift system for hoisting 16 tonne canal boats out of the water at the prestigious new centre. This enables passengers, including the disabled, to embark and disembark easily and safely.

The new visitor centre is adjacent to and serves the Standedge Tunnel; the highest (196m), longest (5,200m) and deepest (194m) canal tunnel in the UK. Running beneath the Pennines, the tunnel was originally built to serve England's booming textile industry in the 19th century. Over the last few decades it had fallen into disuse, as had a large section of the Huddersfield Narrow Canal of which it is part. Recently, British Waterways decided to do something about this situation and embarked on a £30m project, part funded by the Millennium Commission and English Partnerships, to restore the 190 year old tunnel and 20 miles of canal.

Located in what used to be the trans shipment warehouse, the visitor centre is unique as the canal actually enters its confines via a spur from the main channel. The spur allows approximately 15m narrow boats to be accommodated for boarding up to 30 passengers, who then travel into the tunnel.

Four-axis lifting system

Central to the boarding operation is a four axis lifting system that actually hoists the 16 tonne canal barge 1.6m out of the water, at a rate of 1m/min, to the level of the visitor centre floor.

The lifting system was designed, manufactured, installed and commissioned by Barnsley engineers Qualter Hall. At the heart of the lift system is a cradle upon which the boat rests, a ladder type structure linking between the two main crossbeams of the lifting device.

It is equipped with a number of rubber support pads to protect the bottom of the boat and allow its mass to be distributed more evenly.

Once manoeuvred into position upon the cradle, the boat is elevated to a raised position, precisely, by four screw jack actuator systems.

These are driven by individual motors and are electronically synchronised by a fieldbus-linked (CTNet) Unidrive inverter system, operating in flux vector mode to ensure the optimum torque for lifting.

The four-axis Unidrive system, including both hardware and software, was designed and built by Control Techniques Drive Centre, based in Telford. It consists of a master Unidrive and three slave Unidrives, each controlling individual screw jack motors. The Unidrives operate in closed loop flux vector control with position and speed calculated from an encoder mounted on each motor shaft.

• Control Techniques
  g121@industrialnetworking.co.uk