Development of a Multi-Purpose Mobile Robot for Concrete Surface Processing

This paper reports on the design and evaluation of an autonomous multipurpose mobile robot for concrete finishing, grinding, and cleaning at construction sites.

The common characteristics of those three applications are rotating tools in contact with the floor. Combined in one machine, they can perform recurrent tasks on a construction site.

In Phase 1, an experimental vehicle was built for tests of navigational concepts including Path planning, Location Measurement, and Path Following.

Steering and locomotion of the experimental vehicle was provided by two independently steered and powered wheels, enabling the vehicle to perform complex manoeuvres as required by the application selected.

Two navigational methods have been tested: A novel detector for locating rebars embedded in the concrete floor to serve as possible references. A scanning laser sensor, LADAR, providing a digitalized image of surroundings, used for locating reference walls, columns, and obstacles.

In Phase 2, a full-scale robot prototype equipped with tools was developed. The navigational concept used is LADAR and dead-reckoning.

Different vehicle/tool configurations have been modelled and simulated in order to find the optimal solution for mobility and surface coverage. Steering and locomotion of the full-scale robot is based on a steered and powered multiple wheel roller either pushing or pulling the vehicle, depending on the type of application. This design, together with specific rotating tools, gives a well-balanced vehicle in all three applications.

The tool unit consists of two counter rotating and overlapping rotors. Depending on application, the rotors can be fitted with different tool blades/discs. The robot is powered via an electric cable, automatically handled by the machine itself. The robot controls position and pull of the cable to avoid running over it or generating undesirable patterns in the concrete.