Multi-Joint Medical Arm Force Control
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Solution Overview
Problem
Current medical support arm devices with redundant degrees of freedom face challenges in controlling position and orientation, particularly in scenarios requiring physical interactions, as they either struggle with flexibility in position control or usability in force control.
Innovation Solution
A medical support arm device with a multi-joint arm configuration having a higher degree of freedom than necessary for spatial position and pointing direction control, utilizing a drive controller to manage the joints and employing force control to enhance user convenience and intuitive operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If position control is used to control the multi-joint arm, then the spatial position and pointing direction of the medical device can be controlled, but the device cannot flexibly respond to external forces
Solution Approach 1:
The patent changes the control parameter from position to force, allowing the multi-joint arm to respond flexibly to external forces while maintaining control. The force control unit adjusts the driving force based on operator input and external force detection, enabling natural interaction between the operator and the medical device.
2Adaptability or versatility
If the multi-joint arm has higher degree of freedom than necessary, then multiple tasks can be performed simultaneously, but the control complexity increases
Solution Approach 1:
The control system is segmented into distinct functional units: a force control unit that handles overall force control, and individual joint control units that manage specific joints. This segmentation allows the complex multi-joint arm to be controlled through modular, independent control units, reducing overall system complexity while maintaining multi-task capability.
Solution Approach 2:
The force control unit acts as an intermediary between the operator's input and the multiple joint control units. It processes the operator's force input and distributes appropriate control signals to each joint, simplifying the control architecture while enabling coordinated multi-joint operation for multiple tasks.
3Ease of operation
If force control is applied to the multi-joint arm, then soft control with higher usability is achieved, but the precision of position and orientation control may be affected
Solution Approach 1:
The system incorporates feedback mechanisms where the force control unit continuously monitors operator input and external forces acting on the medical device. This feedback allows the system to adjust the driving force in real-time, maintaining both the soft control characteristics for usability and the precision needed for accurate position and orientation control.
Data Source
AI summary
There is provided a medical support arm device including a multi-joint arm having a distal end configured to host a medical device, said multi-joint arm configured to have a higher degree of freedom than a degree of freedom necessary for controlling a spatial position and pointing direction of the medical device. The multi-joint arm is configured to controllably displace at least one of a plurality of joints of the multi-joint arm while the spatial position and the pointing direction of the medical device are controlled.