Machine control developments from Leica Geosystems, Topcon, Trimble and Wirtgen in the slipforming sector

Machine control technologies were pioneered in the concrete paving sector with systems having been used for over 10 years. Leica Geosystems was the first of the machine control technology suppliers to offer these systems on concrete slipforming machines and has developed a strong position in this segment. However the company met resistance from some quarters in the construction market and specialist Karl Soar said that some contractors were very reluctant to give up using conventional stringlines. He said, “We provide tools so they can stay in the comfort zone.”

The introduction of machine control systems to paving has changed the way operations work, as well as the duties of those on-site and for example, Soar said that the surveyor has now become a data manager as this is effectively a quality management operation. Machine control systems have brought benefits and Soar said, “It’s all about performance contracts these days.”

He added that squeezed time schedules place pressure on either finish or completion times, which is why the machine control technologies are important for achieving the necessary smoothness within project deadlines.

342 Topcon was next to enter the market for machine control technologies in concrete slipforming. It introduced its package a few years ago and its systems are now offered by a number of the paver manufacturers as an alternative. 307 Power Curbers for example says that its machines can be equipped with either 265 Leica Geosystems or Topcon control packages, as the manufacturer is keen to allow the customer to choose the preferred system rather than dictating which can be used.

Most recently 2122 Trimble has entered this sector with its sophisticated PCS900 system, which can now be used on slipform pavers (as well as milling machines), in addition to the asphalt pavers for which it was originally developed. The system now features extra technology that will increase its accuracy such as a gyroscope that measures lateral movement in the three axes as well as rotational movements, and provides accurate slope sensing capabilities. For wide paving applications, two gyroscopes can be fitted to provide accurate slope sensing from either side of the slipformer. Rugged and compact, the gyroscope is a tough and durable industrial unit that is also comparatively inexpensive. Another feature that will help boost productivity and efficiency is its total universal station capability. With the previous system users had to change channels when moving from one total station to another but now all the stations are connected on the same radio channel. This allows the machine to be run continuously, without needing to reset the control unit and allowing considerable productivity gains across a working shift, as well as helping with continuity with regard to finish.

In addition, 2395 Wirtgen has developed its own AutoPilot Field Rover system, which allows fully automatic paving, boosting productivity. The 3D control system comprises a computer integrated into the machine and a control panel. Two GPS receivers mounted on the machine communicate with a GPS reference station on the job site. There is no need for a digital terrain model as surveying and programming can be carried out on-site. The system is said to be simpler to use than conventional stringline-free 3D systems and allows minor changes to be made quickly on-site.

The software calculates the optimum course on the basis of the measured points, creating a virtual stringline and data is saved on a USB stick for use on the machine. The paver then follows the file on the stick, moves to the start point and then follows the files created. The system bases its calculations on the actual job site measurements and does not require construction drawings and is said to be less costly than conventional 3D technology.