초록 ▼

The invention relates to non-destructive measurement of the firmness of fruits and vegetables, particularly to methods and equipment for measuring the firmness of such edible objects in order to establish their ripeness or maturity stage, not only after they have been harvested or stored, but also d

The invention relates to non-destructive measurement of the firmness of fruits and vegetables, particularly to methods and equipment for measuring the firmness of such edible objects in order to establish their ripeness or maturity stage, not only after they have been harvested or stored, but also during the growing process. The method comprises:- 1) gripping the object in two substantially diametrical points between two gripper bodies at a predetermined pressure, 2) applying a vibrational excitation onto one of the two points by means of a vibration actuator using a composite signal with predetermined frequency content, amplitude range and phase shift configuration, specialized for the kind of fruit to be tested, 3) measuring the input signal by means of a first acceleration transducer attached to a gripper body on the vibration actuator contacting one side of said object 4) measuring the output signal on the other side of said object by means of a second acceleration transducer attached to an opposite gripper body, 5) passing the signals through a difference amplifier and obtaining a relative acceleration signal by deducting the input signal from the output signal, 6) feeding the obtained signals to computer means and obtaining a firmness index by the quotient of the root mean square of the output acceleration signal divided by the root mean square of the relative acceleration signal. The equipment may comprise manually or automatically operated table-top or hand-held “FIRMNESS TESTERS”or “FIRMNESS SENSORS”that can be mounted as robotics end-effectors or incorporated in a cup-conveyor line for automatically sorting fruits and vegetables by firmness, in a packinghouse.

대표청구항 ▼

A method of measuring and testing the firmness of a fruit or a vegetable in order to determine its ripeness stage comprises the steps of: gripping said fruit or vegetable in two substantially opposite points between two bodies at a force or pressure not liable to cause damage to said fruit or vegeta

A method of measuring and testing the firmness of a fruit or a vegetable in order to determine its ripeness stage comprises the steps of: gripping said fruit or vegetable in two substantially opposite points between two bodies at a force or pressure not liable to cause damage to said fruit or vegetable; applying a vibrational excitation onto said fruit or vegetable at one of said two opposite points by means of a vibration actuator using a narrow band random signal or a composite signal with predetermined frequency content, composed of a sum of sinusoids with frequencies, amplitudes and phase shifts specialized for the kind of fruit or vegetable to be tested; measuring the input acceleration signal by means of a first acceleration transducer attached to said vibration actuator; measuring the output acceleration signal by means of a second acceleration transducer at the opposite point of said fruit or vegetable; passing the input and output acceleration signals through a difference amplifier to effect deduction of said output signal from said input signal to obtain a relative acceleration signal in real time; feeding the obtained relative acceleration signal as well as the output acceleration signal to analog or digital computer means programmed to compute, store, indicate or display a firmness index value by dividing the root mean square of the output acceleration signal by the root means square of the relative acceleration signal.