Method for decomposing contact forces and haptic device applying the same

Contact Force Decomposition Technology for Separating Shear Force via Resultant Normal Force Calculation Using Multiple Pressure Sensors

This technology is a contact force decomposition method and haptic device that measures contact pressure from multiple micro-contact surfaces arranged at different angles on the surface of an external force application unit, and calculates the shear force component by vectorially subtracting the resultant normal force from the total measured contact force.

Existing haptic devices can only measure the total resultant force generated during object contact, leading to low accuracy in reaction force estimation because they cannot precisely decompose changes in contact surface geometry due to object deformation or changes in the direction of normal and shear forces.

This technology proposes a method that derives the resultant normal force using the geometric normal information of the sensors and then extracts the shear force through vector calculation with the contact force sensor values. It can be applied to surgical robots and teleoperated haptic interfaces to precisely decompose contact states into normal and tangential components, enabling realistic force feedback.

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Key Features:

• Measuring contact pressure from multiple micro-contact surfaces positioned at different angles between the target object and the external force application unit
• Measuring the total contact force acting on the external force application unit by the target object using sensors
• Determining the resultant normal force, which is the force in the normal direction of the multiple micro-contact surfaces, from the measured contact pressure
• Calculating the shear force, which is the planar force acting on each micro-contact surface, based on the resultant normal force and the total contact force

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This invention was developed with support from the Ministry of Science, ICT and Future Planning's Research Center for Local Projection Imaging and Haptic-based Surgical Robot Technology.