Flexible Robot End Effector Pose Sensing From Curvature and Tactile Data
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Solution Overview
Problem
Flexible robotic end effectors face challenges in precisely determining the pose of objects due to their compliance, which makes it difficult to achieve precise placement, especially in pick-and-drop scenarios like bin picking, where the uncertainty in object orientation complicates the computation of contact points on continuously deforming surfaces.
Innovation Solution
The integration of multiple discrete curvature measurements along the flexible surface using tactile and curvature sensors to develop a curvature kinematics model, allowing for the computation of forward kinematics of contact points and generating a 'point cloud' in space, effectively transforming the flexible surface into a dense-geometry sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If flexible end effectors are used to grasp oddly shaped objects, then adaptability is improved, but measurement precision deteriorates due to continuous deformation making pose determination difficult
Solution Approach 1:
The flexible end effector is divided into multiple discrete segments along its length, with each segment equipped with curvature sensors. This segmentation transforms the continuous flexible surface into discrete measurement points, enabling pose determination while maintaining flexibility for grasping various object shapes.
Solution Approach 2:
The patent replaces traditional mechanical pose determination methods with sensor-based measurement systems. Curvature sensors and tactile sensors substitute for mechanical encoders, providing continuous feedback on the flexible end effector's configuration and contact points without requiring rigid mechanical structures.
2Measurement precision
If curvature sensors and tactile sensors are integrated along the flexible surface, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The flexible end effector structure serves multiple functions: it acts as both the grasping mechanism and the sensor substrate. The same flexible material that enables adaptation to various object shapes also serves as the mounting surface for curvature and tactile sensors, eliminating the need for separate sensor platforms or complex mounting structures.
Solution Approach 2:
The patent merges the structural components with sensing components by integrating sensors directly into the flexible end effector. The flexible material itself becomes part of the sensing system, combining mechanical function and sensing function in a single integrated structure rather than separate components.
3Manufacturing precision
If discrete curvature measurements are taken along the flexible surface, then manufacturing precision is improved, but loss of information increases due to gaps between discrete measurement points
Solution Approach 1:
The patent achieves continuous measurement capability through dense placement of discrete curvature sensors along the flexible end effector. By positioning sensors at multiple points throughout the length of each segment, the system continuously captures deformation information across the entire flexible surface, eliminating information gaps between measurement points.
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
This approach enables accurate determination of the object's pose, allowing for precise robot movement and placement by localizing sensor data and generating continuous data for pose estimation algorithms, thereby improving the precision of object placement in robotic systems.
Implementation Method 1
one or more curvature sensors positioned to sense a curvature of each one of the one or more flexible fingers and generate curvature data corresponding to the curvature
Implementation Method 2
one or more tactile sensors positioned adjacent to each one of the one or more flexible fingers, the one or more tactile sensors configured to sense a location of one or more deformations of the flexible internal side member caused by a contact between the flexible end effector and the object held by the flexible end effector
Data Source
AI summary
Systems and methods for determining a pose of an object held by a flexible end effector of a robot are disclosed. A method of determining a pose of the object includes receiving tactile data from tactile sensors, receiving curvature data from curvature sensors, determining a plurality of segments of the flexible end effector from the curvature data, assigning a frame to each segment, determining a location of each point of contact between the object and the flexible end effector from the tactile data, calculating a set of relative transformations and determining a location of each point relative to one of the frames, generating continuous data from the determined location of each point, and providing the continuous data to a pose determination algorithm that uses the continuous data to determine the pose of the object.