Palm-Mounted 3D Robotic Gripper for Precise Small-Object Handling
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Solution Overview
Problem
Current robotic grippers face challenges in achieving high-resolution 3D perception and precise manipulation of small objects due to limitations in optical systems, calibration errors, and stiffness variability, which hinder their ability to perform tasks like bin picking and peg-in-hole insertion efficiently.
Innovation Solution
A robotic gripper with a palm-mounted mechanical manipulation system, including multiple fingers, a light projector, and stereo camera sensors, which allows for real-time 3D perception and adaptive stiffness control, enabling precise object manipulation and grasping within a defined workspace.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical systems are mounted above the robot's workspace, then the robot can perceive objects, but the resolution is insufficient for small objects and the robot must move outside the work cell increasing cycle time
Solution Approach 1:
The patent merges the optical sensing system with the robot's end effector by mounting cameras directly on the gripper fingers. This integration allows the robot to maintain high-resolution perception of small objects while operating within the work cell, eliminating the need to move outside the workspace and reducing cycle time.
Solution Approach 2:
The patent introduces an intermediary optical system mounted on the gripper itself rather than above the workspace. This intermediary positioning provides a closer view of objects being manipulated, achieving millimeter or sub-millimeter resolution while allowing continuous operation within the work cell boundaries.
2Measurement precision
If optical systems are mounted on the robot's arm or wrist, then calibration errors can remain constant, but the workspace is reduced and collisions increase
Solution Approach 1:
The patent combines the optical sensing system with the gripper structure itself, mounting cameras on the fingers and palm. This merging eliminates the need for separate mounting on the arm or wrist, preserving the full workspace while maintaining constant calibration relationships between the sensors and the manipulation point.
Solution Approach 2:
The patent transitions from mounting sensors on the arm/wrist (higher up in the kinematic chain) to mounting them on the gripper fingers (at the end of the kinematic chain). This dimensional repositioning brings the sensors closer to the manipulation point without restricting the arm's range of motion or increasing collision risk.
3Force
If the robotic gripper is made stiff, then forces can be transduced to the wrist, but compliance is reduced for delicate manipulation
Solution Approach 1:
The patent implements dynamic stiffness control by equipping the gripper with force sensors and control systems that can adjust compliance in real-time. The gripper can be stiff when force transduction is needed and compliant when delicate manipulation is required, adapting to different task requirements throughout the operation cycle.
Solution Approach 2:
The patent incorporates force sensors in the gripper fingers and wrist-mounted load cells that provide feedback to the control system. This feedback enables the robot to sense contact forces and adjust gripper stiffness dynamically, maintaining both force transduction capability and compliance as needed for different manipulation tasks.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The gripper achieves improved perception and manipulation capabilities, allowing for accurate grasping and placement of small objects with submillimeter precision, reducing cycle time and energy consumption while accommodating varying task requirements.
Implementation Method 1
at least one light projector mounted to, on or in, or connected operably, to the palm and configured to illuminate at least partially with light having predetermined characteristics the one or more objects located within the workspace or target volume
Implementation Method 2
the at least two camera sensors mounted to, on or in, or connected operably to, the palm and configured and positioned to sense at least one of reflected and backscattered light having the predetermined characteristics and originating from the light projector
Data Source
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AI summary
Disclosed are various embodiments of a three-dimensional perception and object manipulation robot gripper configured for connection to and operation in conjunction with a robot arm. In some embodiments, the gripper comprises a palm, a plurality of motors or actuators operably connected to the palm, a mechanical manipulation system operably connected to the palm, a plurality of fingers operably connected to the motors or actuators and configured to manipulate one or more objects located within a workspace or target volume that can be accessed by the fingers. A depth camera system is also operably connected to the palm. One or more computing devices are operably connected to the depth camera and are configured and programmed to process images provided by the depth camera system to determine the location and orientation of the one or more objects within a workspace, and in accordance therewith, provide as outputs therefrom control signals or instructions configured to be employed by the motors or actuators to control movement and operation of the plurality of fingers so as to permit the fingers to manipulate the one or more objects located within the workspace or target volume. The gripper can also be configured to vary controllably at least one of a force, a torque, a stiffness, and a compliance applied by one or more of the plurality of fingers to the one or more objects.