Multi-Force Sensing at Robot Finger Bases for Haptic Feedback
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Solution Overview
Problem
Existing robotic grasping devices lack the ability to accurately sense the direction of forces applied by robot fingers, leading to incomplete haptic feedback and potential control issues in dangerous or unpleasant environments.
Innovation Solution
The implementation of multi-axis force-sensing systems on the base of robot fingers, allowing for the measurement of forces in three spatial directions, which are then communicated to a data processing system to generate precise haptic feedback control signals, eliminating the need for actuator effort sensing and reducing noise from vibrations and heavy grasping devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If actuator effort sensing is used to estimate forces applied by robot fingers, then force measurement is achieved, but the direction of applied forces cannot be sensed
Solution Approach 1:
The force sensing function is segmented from the actuator and distributed to individual tactile pads on each robot finger. Each tactile pad independently measures force components at its location, enabling both magnitude and direction detection. This segmentation allows the system to capture spatial distribution of forces and their directions, which would be lost in a centralized actuator effort measurement approach.
2Loss of information
If tactile pads are placed on robot fingers to measure applied forces, then force direction can be sensed, but noise from vibrations and heavy grasping devices increases
Solution Approach 1:
The force sensing function is extracted from the actuator and implemented as separate tactile pad sensors mounted on the robot fingers. This extraction allows the sensing elements to be positioned close to the interaction points with objects, enabling direct measurement of contact forces while isolating the sensing function from the heavy actuator components that generate vibrations.
3Measurement precision
If multiple force sensors are placed on each finger to measure forces in three spatial directions, then complete force information is obtained, but device complexity increases
Solution Approach 1:
Each tactile pad is designed as a multi-functional sensor element that measures multiple force components (Fx, Fy, Fz) simultaneously. This multi-functionality allows a single sensor unit to provide complete three-dimensional force information, eliminating the need for multiple separate sensors and reducing overall system complexity while maintaining full spatial measurement capability.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A robotic grasping device (10) has a first finger (20), a second finger (30) and an actuator (40). The first finger has a first fingertip (22), a first base (24) and a first actuator engagement end (26). A first gripping surface (21) of the first finger lies between the first fingertip and the first base. Similarly, the second finger has a second fingertip (32), a second base (34), a second actuator engagement end (36). A second gripping surface (31) of the second finger is between the second fingertip and the second base. The actuator (40) mechanically engages with the first actuator engagement end and the second actuator engagement end to open and close the fingers. A first force sensor (28) is disposed on the base of the first finger to measure a first operative force on the first finger, and a second force sensor (38) is disposed on the base of the second finger to measure a second operative force on the second finger.