Sensors put the smart into safer materials handling

It is also requiring new ways of thinking across all aspects of materials handling, especially when it comes to reducing accidents in the workplace. This in turn, is presenting a new challenge to sensing and control manufacturers to ‘design-in’ safety.

Sensors and encoders feature throughout an AGV design, one of the
most important being to control steering. Essentially there are three different types:

1. The three-wheel steering control configuration is the most common solution for lift truck AGVs. They are relatively easy to implement and provide very accurate control. Frequently, this design relies on encoders to monitor and measure the speed and direction
of one master wheel that determines the vehicle’s movement. 

2. The differential configuration is a popular solution for unit load carrier and tow-vehicle AGVs since it is possible to rotate around the centre of the vehicle, although with some turning limitations. The steering control is achieved using different speeds in either
forwards or backwards directions on the two controlled wheels, where a single motor and an encoder are used on each wheel. 

3. A quad wheel configuration provides the most manoeuvrability as it permits 360° of movement in any direction, making it the ideal solution for unit load carriers. The ability to steer
the vehicle in a sideways or crabbing motion allows for better and more accurate navigation in tighter and more challenging spaces. As there are more wheels that require steering controls and accompanying motion control components such as encoders and sensors, this type of configuration is the most complex. 

Read the full article in the October issue of DPA