Features & Interviews

Feature: Examining the ergonomics of cab design

12 May 2015 #Features & Interviews

How are manufacturers approaching cab design and what does this mean for drivers and operators? Transport News Brief spoke to the industry to find out more.

Gone are the days when the design of truck cab interiors was treated as an afterthought, with zero attention given to creature comforts. Aware that drivers have a major influence on purchasing decisions, manufacturers today take infinite pains to create a comfortable yet efficient working environment and are employing sophisticated virtual tools to do so.

Among those manufacturers is Daimler, which uses software called RAMSIS to simulate human models to provide useful insights into areas such as fields of vision and how much in-cab space drivers have available to them.

There is only one problem with RAMSIS says Daimler ergonomics researcher, Richard Sauerbier, it is too static. “Studies into the ergonomics of trucks cover a much wider spectrum than passenger cars,” he points out. “Replicating movements inside a truck cab such as lying down, standing up or opening stowage compartments represent a major challenge; and that’s before we start talking about the complex process of climbing in and out of the cab using several steps and grab handles.”

To address this challenge Daimler has involved itself in the Applied Reference Architecture for Virtual Services and Applications project with 22 partners including various German academic institutions and funding from the German Federal Ministry for Research and Industry. As part of its involvement Daimler appeared at the recent CeBIT show in Hanover – one of the world’s largest information technology trade fairs – with a Mercedes-Benz Actros and conducted an exercise entitled ‘climbing into the cab’.Daimler Trucks demonstriert auf der CeBIT 2015 an einem Mercedes

The individual was adorned with around 60 optical markers to supply data on every movement made which was recorded and evaluated by Daimler engineers.

Armed with this sort of information, designers can create 3D digital mock-ups of the way people move into, out of and around the cab and use them at the concept stage of a vehicle. Daimler aims to have this tool to hand by the end of 2016.

It is easier, cheaper and quicker than building full-size cab mock-ups and have up to 50 people of different shapes and sizes climb in and out of them, which is what happens at the moment.

The extent to which the detail of ergonomics matters is illustrated by the interior of Volvo’s FH and the way the steering wheel is designed. It comes with an optional adjustment, which allows it to be tilted rather than simply raised or lowered.

“When your arms drop down a bit your driving improves,” remarks design engineer, Peter Johansson.

Use all the adjustments available and the wheel can be angled by up to 40 degrees.

The steering wheel buttons are more ergonomic with a handy thumb wheel that can be used to control the instruments and scroll through menus. The buttons and stalks are given shapes and surfaces that make them easily identified with fingertips to ensure the driver’s eyes are on the road.T2013_0001

The driver’s seat can be slid back 4cm further than the previous FH, raised and lowered by up to 10cm and has been re-shaped with more leg support. Volvo is convinced it has got this right but it is a tricky area; too little leg support is no good, but too much makes it harder for the driver to get in and out of the seat.

Getting the position of the driver’s seat spot-on can be a challenge, says a senior MAN design engineer. “It depends on many other influences including the steering column position, the angle of the windscreen and the width of the bed,” he points out.

Use 3D software to juggle it all and life becomes easier and the driver will reap the benefits.

Successful cab interior design involves thinking carefully about the working lives of drivers. They have to climb in and out of the cab in all weathers and sometimes get soaked by heavy rain. And who wants to spend two or three days sharing a cab with a sopping-wet jumper? As a consequence FH is equipped with a foldaway drying cupboard.

“It’s a textile bag with a fan at the bottom,” explains Johansson. “When it’s not in use you simply fold it up and put it away. It’s perfect for a wet jacket; and for smaller wet items like hats and gloves.”

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