Force-Controlled Robotic Gripper for Unknown Object Positions
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Solution Overview
Problem
Existing robotic end-effectors with articulated linkages lack sufficient degrees of freedom for independent control of position and orientation, limiting their range of behaviors when interacting with objects, and require precise object location for manipulation.
Innovation Solution
A robotic gripping device with motorized linkages and rotary joints that are force and torque controllable, allowing for software-controlled manipulation of objects without knowing their precise location, using the Jacobian transpose to determine interaction behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If under-actuated linkages are used in robotic end-effectors, then device complexity is reduced, but the range of behaviors when interacting with objects is limited
Solution Approach 1:
The patent implements force/torque controlled rotary joints that dynamically adjust their mechanical impedance during interaction with objects. This allows the linkage to transition between compliant and rigid states, enabling a broader range of manipulation behaviors while maintaining simpler under-actuated mechanics. The dynamic control of joint stiffness compensates for the reduced degrees of freedom.
Solution Approach 2:
The invention changes the control parameter from position control to force/torque control at the rotary joints. This parameter transformation allows the same mechanical structure to exhibit diverse behaviors by varying the applied forces and torques, effectively increasing the range of behaviors without adding mechanical complexity.
2Measurement precision
If precise object location is required for manipulation, then manipulation accuracy is improved, but the system cannot handle unknown object positions
Solution Approach 1:
The force/torque controlled linkage performs self-positioning through compliant interaction with the object. Instead of requiring precise prior knowledge of object location, the system allows the object's physical properties and the applied forces to guide the linkage to the correct manipulation position automatically.
Solution Approach 2:
The patent employs force/torque sensing feedback from the rotary joints to continuously adjust the linkage configuration during interaction. This real-time feedback enables the system to adapt to unknown object positions and achieve accurate manipulation without requiring pre-known object location data.
3Adaptability or versatility
If multiple grippers are used to handle diverse objects, then adaptability is improved, but device complexity increases
Solution Approach 1:
The force/torque controlled linkage serves multiple manipulation functions (grasping, pushing, rolling, lifting) through a single unified mechanical structure. By controlling the forces and torques at the rotary joints, the same linkage can adapt its behavior to handle diverse objects and perform various manipulation tasks, eliminating the need for multiple specialized grippers.
Data Source
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AI summary
A robotic gripping device, system and method is described. The robotic device comprises an end effector having at least one finger, the fingers being capable of manipulating objects in the vicinity of the device under computer control. The device is capable of manipulating objects of varying sizes, dimensions and positions with reference to the device, without requiring information as to the precise location of the object with reference to the device.