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

An item picking system configured to pick items 132 from a collection region for placing said items 132 into an item container 142 comprises one or more end effectors 120 coupled to a robotic arm 110 for holding and manipulating an item, at least one of the end effectors 120 comprises a contact pressure sensing assembly 210 including a piezoresistive sensor 201, 202, 203, 204 to obtain signals indicative of contact pressure between the sensor 201, 202, 203, 204 and an item 132 held by the end effector 120. Signal processing circuitry 230 processes the piezoresistive signals, the signal processing circuitry comprising a differential amplifier 234 having a first input terminal coupled to the sensor 201, 202, 203, 204 to receive piezoresistive signals, a second input terminal arranged to receive a calibration signal such as from a calibration amplifier 239 and an output terminal providing a difference signal based on the two input signals. For each piezoresistive signal provided to the differential ...

System and Method for Picking and Placing Items and Contact Pressure Sensing Assembly for Item Picking Systems

A contact pressure sensing assembly 210 comprises an electronic skin for digits of an end effector of a robotic arm, wherein the electronic skin comprises a plurality of piezoresistive sensors, a plurality of piezoelectric sensors and a control unit 230 coupled to the electronic skin to receive piezoresistive and piezoelectric signals from the sensors. The control unit processes the piezoresistive signals to identify one or more piezoresistive parameters and processes the piezoelectric signals to identify one or more piezoelectric parameters in order 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. The control unit determines a contact pressure between the item ...

System and Method for Picking and Placing Items and Contact Pressure Sensing Assembly for Item Picking Systems

An item picking system configured to pick items from a collection region for placing the items into an item container comprises a robotic arm and an end effector coupled to the robotic arm comprising at least two digits for holding and manipulating an item and a contact pressure sensing assembly 210 comprising an electronic skin at least partially covering the digits and comprising a plurality of piezoresistive sensors and a plurality of piezoelectric sensors, the system further comprises a control unit 230 configured to control operation of the digits based on piezoelectric signals and piezoresistive signals received from the electronic skin. The control unit may identify that an item held by the digits is moving relative to the electronic skin based on a difference in magnitude and/or phase between one or more voltage parameters for piezoelectric signals from one piezoelectric sensor and one or more voltage parameters for piezoelectric signals from another piezoelectric sensor. The control ...

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