MintDrive enhances sports action camerawork

Innovative motion control technology incorporated in Camera Tracking Company's latest mobile camera system is providing the first close-up filming of vertical sports action.

Innovative motion control technology incorporated in Camera Tracking Company's latest mobile camera system is providing the first close-up filming of vertical sports action such as pole vaulting without track-side operators or cranes.

Housed inside a 14cm-high case with a vertical slide for the video camera, the system is controlled remotely over a network from a terminal which can be sited up to half a kilometre away.

Used for the first time at the Sydney Olympics to cover pole vault, shotput and football goalmouth action, the system sets new standards for compactness and remote controllability.

At the heart of the unit is the 'smart' MintDrive from Baldor which integrates the usually separate motion controller and electric motor drive into one compact box, and provides a fieldbus interface for communicating with it via a network.

These attributes allowed Camera Tracking Company (CTC) to construct the single-axis mobile camera controller in a little over half the space normally needed, and control it via a single cable - typically utilising standard microphone cabling which is often already in place at locations, or easily prerigged via contractors.

The complete system is packaged in a box which stands 14cm high, with folding support legs.

"The space saved by using the all-in-one MintDrive has allowed us to create an automated mobile camera that can be located right next to the action", says Sam Heaphy, Director of CTC, part of the Aerial Camera Systems group.

"The technology gives broadcasting companies the means to provide unforgettable close-ups of a new class of sports events including pole vault, discus and shotput".

The motion control system consists of a MintDrive with a matched performance brushless servomotor - which Baldor provides with a special shaft to fit an existing gearbox design - connected to a belt-driven linear slide to carry the camera.

The slide is mounted on an aluminium extrusion which CTC provides in lengths of four or seven metres according to the event being covered.

MintDrive's integral CAN fieldbus interfaces were key to CTC's selection of the product, allowing it to send camera movement commands using the standard CANopen protocol, and to exploit CAN's versatile network sizing mechanism which allows data communications speed to be traded off against distance.

In this instance, CAN is typically providing a 100Kbit/s datalink over distances up to 500m.

At the remote terminal end of the system, the operator uses a joystick and switches to manipulate the camera.

"Normally, the CAN network is used to link to I/O or other drives which might be up to a few metres distant around a machine", adds Baldor's Eliza Rawlings.

"In this instance the versatility of the bus is really being exploited, allowing a man-machine interface to be positioned at extreme range - in a truck compound outside the stadium - to ensure unimpeded visibility in the sports arena".

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