System and method for picking and placing items and contact pressure sensing assembly for item picking systems

A contact pressure sensing assembly comprising:

• an electronic skin for digits of an end effector of a robotic arm, wherein the electronic skin comprises:
• a plurality of piezoresistive sensors each configured to obtain piezoresistive signals;
• a plurality of piezoelectric sensors each configured to obtain piezoelectric signals;
• a control unit coupled to the electronic skin to receive the piezoresistive and piezoelectric signals therefrom;
• wherein the control unit is configured to process the piezoresistive signals to identify one or more piezoresistive parameters associated therewith, and to process the piezoelectric signals to identify one or more piezoelectric parameters associated therewith;
• wherein the control unit is operable to identify that an item held by the digits of the end effector is moving relative to the electronic skin based on a difference in magnitude and/or phase between:
• (i) one or more of the piezoelectric parameters in piezoelectric signals from one piezoelectric sensor, and (ii) one or more of the piezoelectric parameters in piezoelectric signals from another piezoelectric sensor;
• and
• wherein the control unit is configured to determine a contact pressure between the item and a first digit associated with said one piezoelectric sensor based on one or more of the piezoresistive parameters from piezoresistive signals associated with the first digit.

An item picking system configured to pick items from a collection region for placing said items into an item container, the system comprising:

• a robotic arm;
• and
• an end effector coupled to the robotic arm comprising at least two digits for holding and manipulating an item therebetween, wherein the end effector comprises a contact pressure sensing assembly;
• wherein the contact pressure sensing assembly comprises an electronic skin arranged to at least partially cover the digits of the end effector, the electronic skin comprising:
• (i) a plurality of piezoresistive sensors each configured to obtain piezoresistive signals;
• and (ii) a plurality of piezoelectric sensors each configured to obtain piezoelectric signals;
• wherein the system comprises a control unit configured to control operation of the digits based on piezoelectric signals and piezoresistive signals received from the electronic skin.