Harvesting and loading of products, such as beans, sugarcane and some horticultural ones require a precise ground contouring process. Lifting forks should neither get away from the ground surface nor penetrate into it in order to avoid losses in the first case or product contamination with silt or soil bacteria in the second case. Active or passive mechanisms can be used to follow the ground profile. Lifting or cutting devices can be mounted on linkages having instant rotation centers adequately located for optimum flotation performance. The reference point of the ground following process should be close enough to the lifting or cutting point to avoid position errors resulting from ground surface unevenness. The main limitations of the articulated fork of the combine sickle bar and the double disk base cutter of the Australian sugarcane harvesters are discussed and alternative solutions are proposed to improve ground following performance. Research results of passive mechanisms having low and high mass are discussed together with an active control system for a combine header.
harvesting; loading; ground sweeping; mechanisms; control
