HOW TO KEEP IT SAFE
To safely operate automated rigging systems , one must be well versed in the basics of entertainment rigging and the mechanics of motion .
It is easy to get carried away with the power of automation . With such bountiful opportunities and clients with eyes so wide , it ’ s easy to push limits . Understanding these limits is the key to safe operation .
Modern systems have many built-in failsafes to keep the operator well within the safe working capacity of their rigs ; however , if you don ’ t know the basic rigging principles , you ’ re at great risk of making a catastrophic mistake .
Design your rig and systems from the ground up , remembering that the entire show depends on your weakest link . All your safety precautions will be for nothing if you don ’ t correctly attach your automation to the truss or video wall and whatever supports it . You must know the safe limits of your venue and your equipment , so plan thoroughly . Getting it right the first time is essential .
Like all forms of entertainment rigging , your success starts at the top . Fully understanding what the capacity in a particular venue is , how to properly rig there , and how to correctly install your rigging , including bridling , is crucial . If your basket up top is incorrect , then anything you do below that will be incorrect . Whether you are attaching your automated hardware directly to the roof , via a mother grid system , on a fly rail , or any other variation , you must understand the working limits of your particular situation . Understanding and working within these limits is the best way to produce movements that are not only visually stunning , but also safe .
Let ’ s talk more about limits . Limits are ways to keep your rig within its safe working parameters . There are soft limits and hard limits .
Soft limits are programmed into the software and are dependent on your encoder . This is a value you program based on a zeroing of your rig to match your virtual space and the physical space . If your lower soft limit is programmed at a distance that is below your stage in physical space , and you write a cue to go to that position , you ’ re going to have a bad day . Conversely , if your upper soft limit is higher than an obstruction , you will drive your rig into whatever is in its way . These limits are crucial for working within a safe boundary .
On the other hand , rigging hardware like hoists , and winches , and trolleys will have hard limits . These are mechanical limits in the form of switches that can remove power from the contactor , restricting the available direction of travel at an electrical level . In a hoist , the hard ( or mechanical ) limit is just what you think it is – the same hard limit that you are used to with a conventional fixed speed hoist . This is typically a shaft attached to the hoist ’ s drive that has a travel plate . As the hoist moves up and down , the plate
U2 ’ S 360 TOUR “ VIDEO FUNNEL ,” MOTION CONTROLLED WITH VARIABLE SPEED WINCHES AND APPROX . 40 VARIABLE SPEED CHAIN HOISTS . spins to one side of the shaft or the other . When it reaches a certain point , it will make contact with the limit switch , cutting power to that direction of travel .
Hard limits usually won ’ t change , but your soft limits will . It is of great importance that as you build your automated system , you measure and program these soft limits to ensure you don ’ t try to program a cue that could cause a collision .
Other limitations to consider are speed clamps to limit the velocity of travel , load detection to limit the amount of force a system will exert , and safety precautions such as remote emergency stop switches , “ deadman handles ” to assure the move is being authorized by a spotter , etc .
Light switches and curtains can avoid unsafe movements just as an electric garage door can be stopped if a beam of light is interrupted in the doorway . Some control software systems even feature collision avoidance for constructs in a virtual 3D environment . There are CSA standards for industrial automation and the same principles apply here . If there is a risk or danger , the system must be designed to eliminate or mitigate it . This could be redundant components checking each other , secondary brakes , and higher safety design factors for life-safe critical elements .
Finally , let ’ s talk about dynamic loads . In conventional rigging , you are calculating a static load and compensating for shock loads as you start and stop travel . In automated rigging , you are dealing with potentially higher dynamic loads due to heavy objects that are in motion more frequently and at potentially higher speeds compared to standard machinery .
These loads are much more complicated to calculate as an object moves , and in the real world , this is something that is not easily done on paper . Because of this , higher end systems have introduced integrated load cell systems to provide feedback , and they combine that information with encoder feedback . These systems offer a higher level of safety if not just for the reason that you are able to monitor the applied loads , but many systems can use this data to automatically avoid overloads . There is a large gap between calculating dynamic loads the old-fashioned way and real-time accurate load monitoring .
Being as keen for safety as I am , I always suggest the consideration of load cells in automated rigging systems . There is a lot to be said about the difference between guesswork and hard facts .
IN CLOSING
The entertainment industry is known for pushing the boundaries of technology . Entertainment designers are often at the forefront of new audio and visual technology and automation is no exception . I am excited for the future of entertainment rigging , and I look forward to the opportunity to work with more automated rigging systems .
As a market for automation , Canada has had huge success with the export of largescale , high-budget automation shows , but the era of more accessible and mid-scale automation is just around the corner . It is no longer just Cirque du Soleil and arena-sized concert tours using this technology ; now , theatre productions , mid-market tours , and more can put this powerful and potentially spectacular technology to use .
Mark “ The Drifter ” Desloges is a freelance touring rigger . He has travelled across North America with acts like Johnny Reid and productions like Let It Be . He is also a climbing rigger for IATSE Local 680 and can be reached at markthedrifter @ gmail . com .
David Bond is Head of Sales , North America , for Kinesys USA .
PHOTO : COURTESY OF KINESYS
PROFESSIONAL LIGHTING & PRODUCTION • 25