Author: Prof. Lahsen HAMMADA –
Department of Agricultural Machinery, The national agricultural school in Meknes
Mobile: 00212 6 643 70 50 94
Email: [email protected]
Find all the contributions from Professor Lahsen HAMMADA here
Development of an intelligent load cell for animals on the farm by Pr Lahsen HAMMADA.
A livestock cell has been developed on the farm (Fig.1 : 3D model). It consists of four dynamometers, the test body of which is of elongated hexagonal shape interposed between a load-bearing platform (Fig.2) and a lower frame (Fig.3). A rubber seal is located between the upper platform and the lower frame for optimal protection of the sensors and connection circuits. Each of the sensors is equipped with a bridge with four active strain gauges to compensate for the effect of the ambient temperature (fig. 4; Fig.5 and Fig.6) and ensure measurement of a portion of the total weight of the animal in a stable position on the upper platform.
The partial load is transferred from the latter to the dynamometer via a ball (Fig.7) equipped with a localized lubrication system that ensures a reduction of friction, a concentration of the insert on a small surface at the bottom of the ball and a perfect vertical adjustment at all times of the weighing process for a quasi-integral transmission of the partial load of the animal.
The four dynamometers are attached to the lower frame itself, equipped with four adjustable feet (Fig.8) and a double bubble indicator to ensure perfect horizontality of the load cell in two perpendicular directions. The actual load cell is very thin (Fig.9) and of very low height given the minimum size of the elongated shape of the dynamometers. This thinness is advantageous for a discreet installation in a shallow pit and aligns with the floor of a corridor to channel the animals to be weighed.
Weighing data can be viewed using a display or sent directly to a computer and integrated into a global crew management tool. The animal can be identified by means of cameras mounted on the animal’s reception and stabilization cage. The data can then be used for individual rationing of the animals according to their needs and the average daily growth targeted in case of fattening and constitute a sales decision support tool by closely following the growth and weight gain curves.
The data are also useful for monitoring the health status of the herd and possibly for a selection target within the herd.
The innovative nature of our load cell lies in the following:
- The dynamometers are of elongated hexagonal shape for better stability of the load cell and for a minimum size;
- Weighing cell at very low height given the minimum size of the elongated shape of the dynamometers. It can be placed directly on the ground or ingested discreetly at ground level in a small pit that matches the shape of the floor in the corridor dedicated to weighing animals. It can also be mounted on wheels to form a mobile weighing unit.
- The partial load, derived from the weight of the animal, is transferred from the upper platform to the dynamometer via a ball equipped with a localized lubrication system that ensures a reduction of lateral friction (elimination of parasitic horizontal braking forces of the animal’s hooves)a concentration of the force on a small surface at the bottom of the ball and a perfect vertical adjustment at all times of the weighing process for a quasi-integral transmission of the animal’s partial load;
- The four strain gauges on the measuring bridges are fully active for thermal compensation, canceling out the effect of the ambient temperature on the weighing results;
- The sum of the four sub-loads derived from the weight of the animal is at any time during the weighing process equal to the total weight of the animal regardless of the location of its four feet on the load-bearing platform. The effect of the eccentricity of the load, with respect to the four dynamometers, on the results of the weighings is negligible.
- Options for mounting and customizing additional devices, such as animal identification cameras, data storage on a computer to be integrated into a global herd management tool, and remote data transfer for remote decision making.
Fig.1. 3D model of the load cell
Fig.2. Load receiving platform for load cells
Fig.3. Load cell lower frame
Fig.4. Elongated hexagonal dynamometer test body
Fig.5. Dynamometer with a bridge with four active meters
Fig.6. Testing the strain gauge bridge unit
Fig.7. Load transmission ball equipped with a localized lubrication system
Fig.8. Adjustable feet (four) attached to the bottom frame of the load cell
Fig.9. Very thin and very low height real load cell