Robot Arm Surface Gesture Input Using Joint Force Sensing
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Solution Overview
Problem
Existing methods for operating robot arms require complex input devices and procedures, making it difficult to simplify the process of entering input commands.
Innovation Solution
A method that uses force and/or torque sensors in the robot arm's joints to detect user inputs applied as symbols on the robot's surface, converting these inputs into two-dimensional trajectories, and then deriving symbols and commands from them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If separate input devices or haptic input devices are provided on the robot structure, then input command generation capability is improved, but device complexity increases
Solution Approach 1:
The patent merges the input device functionality with the robot arm structure itself. Force and torque sensors that are already present in the robot joints are utilized to detect user inputs directly applied to the robot arm, eliminating the need for separate input devices. The robot arm structure serves dual purposes: as the operational tool and as the input interface.
Solution Approach 2:
The robot arm serves itself as the input device. By using the force and torque sensors already integrated into its joints, the robot can detect gestures and commands applied directly to its structure without requiring external or separate input mechanisms. The system uses its own structural components for both operation and input reception.
2Measurement precision
If a flat input surface is required for gesture input, then symbol recognition accuracy is improved, but adaptability to different robot structures is reduced
Solution Approach 1:
The patent transitions from requiring two-dimensional flat input surfaces to accepting three-dimensional curved surfaces. By mapping the contact point trajectory on the three-dimensional robot surface to a two-dimensional representation, the system enables gesture recognition on convex and curved surfaces while maintaining recognition accuracy.
Solution Approach 2:
The system changes the geometric parameters of the input surface from flat to curved/convex. By detecting forces and torques at multiple joints and calculating contact point positions on three-dimensional surfaces, the system adapts to various robot geometries including convex surfaces, eliminating the restriction to flat input surfaces.
3Device complexity
If force and torque sensors in robot joints are used to detect user inputs, then device complexity is reduced, but measurement precision of contact point position may worsen
Solution Approach 1:
The patent introduces mathematical calculations and coordinate transformations as intermediaries between the force/torque sensor measurements and the contact point position determination. By using the robot's kinematic model and transforming forces from multiple joints into contact point coordinates on the three-dimensional surface, the system achieves precise contact point localization using only the existing joint sensors.
Solution Approach 2:
The system segments the measurement process into multiple components: detecting forces at different joints, calculating individual contact point contributions, and combining these segments to determine the overall contact point trajectory. This segmentation allows precise position determination by analyzing force distributions across multiple sensor locations.
Data Source
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AI summary
The invention relates to a method for operating a robot arm comprising the following process steps: Capturing a user input, which the user applies to the surface of the robot arm in the form of a symbol, by the following steps: Capturing a force and/or torque in at least one joint, wherein the force and/or torque is caused by the user input; Deriving a trajectory of the point of contact on the three-dimensional surface of the robot arm; Converting the three-dimensional trajectory of the point of contact into a two-dimensional trajectory; Deriving a symbol from the two-dimensional trajectory; Deriving an input command for the robot arm from one or more symbols.