Joseph
Rizk.

From CAD to an integrated mechanism

We began with the CAD design, then integrated a camera and actuators into the physical prototype. The gripper used one fixed finger and one moving finger, with a gear-driven mechanism providing lateral movement.

Detecting ripeness and size

The vision code analysed colour within an image region to distinguish ripe from unripe raspberries. It then detected each fruit’s contour and estimated its size from its pixel extent, classifying it as small or large. This combined colour-based ripeness detection with an image-based size estimate.

Harvesting and sorting

After release from the gripper, the raspberries dropped into a receiving basket. A separate actuator tipped or redirected this basket to discharge the fruit into the appropriate collection basket at the end of the sequence.

The project brought together mechanical design, camera-based perception, actuator integration and the coordination of gripping and sorting.

1. Extract the points in C

The C program read the image’s pixel data, identified the graph corners and coloured traces, and extracted the coordinates of the points belonging to each trace. It exported these coordinates for numerical processing.

2. Reconstruct the graph in MATLAB

MATLAB took the extracted points, ordered the four corners and computed a projective transformation to correct the tilted graph. It converted pixel coordinates into time and voltage, then reconstructed a clean plot.

The processing also fitted sinusoidal and cubic-polynomial models, selecting the model with the lower root-mean-square error.

3. Connect the workflow in LabVIEW

LabVIEW connected the stages: preparing the image data, running the C extraction, passing the results into MATLAB and producing the graph and output files. The result was one coordinated workflow from image input to numerical data and visualisation.

Starting from the specification

We were given a cahier des charges—the functional requirements and constraints—and had to develop the forest wrench from that starting point. The work covered the engineering calculations and the complete mechanical design.

Dimensioning the transmission

Calculated the gears and selected the transmission ratio to meet the required operation. Load analysis and material selection informed component sizing, while the weight restriction had to be considered throughout the design.

Integrating the complete system

Developed the components and their interfaces into a full CAD assembly, bringing the transmission and supporting structure together as a complete system. The project connected requirements, calculations and detailed mechanical design.