A View from Above - Have you ever watched inspection footage taken by a camera hanging from a cable?

If motion sickness doesn’t stop you from watching, the poor quality of video captured due to camera movement will leave you no more aware of the asset condition than before you played the video file! The Zenith system, developed by Interactive Aerial, combats the issues of unwanted camera movement using a combination of advanced sensors and stabilisation technology.

The Zenith system comprises three pieces of equipment: the Zenith unit, the winch and the controller. Each item of equipment communicates wirelessly with the next, and onboard microcontrollers manage the sensor inputs and motion control. The Zenith unit is lowered by the winch into an asset, and video footage is sent wirelessly to the controller. An operator can move the Zenith unit in a similar way to a pan and tilt camera, but with the ability to lower the Zenith vertically by up to 150m. This makes the Zenith system ideal for inspecting shafts, vessels, tanks or over the side of structures, such as bridges.

At the core of the Zenith unit is a patented coaxial drive, which allows the Zenith unit to hold a heading, and to be rotated through 360 degrees by the operator using a portable control console. A stabilised two-axis gimbal system ensures that the camera head is always level, and a built-in LIDAR rangefinder records the distance to an object of interest so that post inspection measurements can be made using customised software.

The keys to accurate positioning of the Zenith unit are the Inertial Measurement Units (IMUs), which measure acceleration in the x/y/z directions. The acceleration information is used to calculate movement of the Zenith, and to counteract movement with the coaxial drive and gimbal system.

The coaxial drive system uses independently driven counter rotating paddles to generate torque, which is applied to the vertical axis. Varying the speed and acceleration of the paddles allows the torque to be applied bi-directionally, which counteracts the spinning motion usually experienced when lowering a camera on a cable. The gimbal allows the camera head movement to be compensated relative to the body of the Zenith unit, and to allow tilting of the head up and down.

The stabilised camera head can take 18 megapixel still photos, and up to 4K video. A 30x optical zoom allows close-up shots to be taken, and the entire system can be operated autonomously to take consecutive 360 degree panoramas of the inspection environment, lowering the Zenith unit incrementally between panoramas.

The most recent inspection involved lowering the Zenith down a 100m deep tunnel ventilation shaft, built in the Victorian era. The shaft was part brick lined, part bare rock, and approximately 4m in diameter. The Zenith system performed admirably, and the bottom of the shaft could be reached in under 5 minutes. Automated inspection captured areas of interest in spectacular detail, and the rope access team assisting the deployment did not need to descend into the shaft, which greatly increased the overall safety of the operation.

Read the latest issue of the OGV Energy magazine HERE.