HBM Sensors and Software Enable Tenth-of-a-Percent Precision in Geisi Robot
Geisenheim University has developed a new concept for mechanized work on steep slopes: the viticulture robot "Geisi". Geisi shall have the capability to work on slopes of up to 70 percent - remote controlled and without ropes.
Viticulture on steep slopes has shaped the landscape in Germany's wine growing regions. However, the proportion of cultivated steep slopes is steadily decreasing. In 2010, it was down to only 9 percent of the overall area under cultivation. One of the reasons for this is that working these steep slopes is completely done by hand - work that is dangerous, physically demanding and costly. The Institute for Technology at Geisenheim University, however, intends to remedy this situation by substantially facilitating the landscape-shaping viticulture on steep slopes. A team headed by Professor Schwarz set out to develop a new concept for mechanized work on steep slopes: Geisi.
Unlike earlier equipment for mechanized cultivation, Geisi is designed to work remotely and without ropes on slopes with grades up to 70 percent. This leads to significant savings in labor cost and at the same a valuable plus in work safety. A fleet of never-tiring, mechanized steep-slope viticulture robots can offer long-term advantages as well with their ability to autonomously perform typical tasks such as crop protection, mulching or foliage work. Geisi is designedto be available at a substantially lower price than earlier mechanized systems built to work on steep slopes.
To make these goals a reality, the project managers got HBM on board. Strain gauges and the rugged, mobile Somat eDAQ data acquisition system from the test and measurement expert make an important contribution to enabling Geisi to autonomously and reliably move on steep slopes.
Spiked rollers, commonly used in alpine slope mowers, form the basis for the multifunctional transport and drive system that supports persons working on steep slopes. The rollers have an integrated drive train. This guarantees an extremely low center of gravity of the vehicle, which, besides the excellent interlocking of the spiked rollers with the underground, is an important prerequisite to Geisi's rope-less operation on extremely steep slopes. Pairs of rollers each arranged one behind the other allow the innovative tool to safely and optimally move on slopes. For this purpose, the development team first had to modify the drives of the spiked rollers to enable the two- or three-axle Geisi to maneuver as desired.
The steering system of the all-wheel driven work platform on spiked wheels posed a special challenge to the Geisi development team. A skid steer system with rollers running at different rotational speeds on the left and right hand side proved unsuitable because of the spiked rollers' strong interlocking with the underground.
The prototypes were fitted with comprehensive test and measurement equipment for documentation and analysis of the material loading during use. Strain gauges from HBM were installed on the axles used as drive roller suspensions to allow three-dimensional acquisition of the occurring forces and moments. Additional data that was recorded included geographic coordinates (via GPS) as well as CANbus communication and inclination. The rugged, mobile Somat eDAQ amplifier system from HBM was used for data acquisition. The collected information enabled both speed and slip to be computed and resulting in improved programming for precise steering including safe negotiating of curves.
The forces resulting from maneuvering during the test runs were too great, material loading was too high. A passive, articulated steering system without hydraulic cylinders with two crossover stationary and two moving rollers proved to be the ideal solution. It provides a high degree of mobility and reliably prevents slipping of the rollers not used for steering.