Medical Robot Arm Force Control for Stable Compact Positioning
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Solution Overview
Problem
Existing medical robot arms face challenges in achieving high stability, operability, and freedom of movement, particularly when performing medical procedures that require interaction with a patient, due to their large size and limited degrees of freedom, which hinder efficient operation and increase user burden.
Innovation Solution
A medical robot arm system utilizing whole body cooperative control with generalized inverse dynamics and ideal joint control to manage disturbances, enabling high-accuracy positioning and torque detection, allowing for intuitive and stable operation with a small form factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a counter balance weight is equipped in the balance arm to maintain force balance, then the arm unit can be moved smoothly, but the device size increases
Solution Approach 1:
The patent replaces the mechanical counter balance weight system with an active force control system. The force control unit calculates and applies compensatory forces through the actuator to balance gravity and external forces, eliminating the need for physical counter weights and reducing device volume while maintaining smooth arm movement.
Solution Approach 2:
The patent changes the control parameter from passive mechanical balancing to active force control. By dynamically adjusting the generated torque based on real-time arm position and external force measurements, the system achieves force balance without fixed mechanical counterweights, enabling compact device design.
2Device complexity
If position control is used for driving the robot arm, then the system configuration is simple, but the robot cannot easily deal with external force flexibly
Solution Approach 1:
The patent transitions from static position control to dynamic force control. The control system continuously measures external forces and adjusts the actuator output in real-time, enabling the robot arm to adapt flexibly to varying external conditions while maintaining a relatively simple system architecture through integrated force sensing and control.
3Ease of operation
If force control is used for driving the robot arm, then the robot can implement soft control with excellent usability, but the system configuration becomes complicated
Solution Approach 1:
The patent merges the force control functionality into the existing position control system. By integrating force sensors and a force control unit that works alongside the position control unit, the system achieves soft control capabilities without creating a completely separate complex system, thereby improving usability while controlling overall system complexity.
4Device complexity
If only biaxial electric driving is implemented in the balance arm, then the system remains simple, but manual positioning is necessary and stability is reduced
Solution Approach 1:
The patent implements force feedback control where external forces measured by sensors are fed back to the force control unit. This closed-loop control automatically adjusts the actuator output to compensate for external disturbances, eliminating the need for manual positioning and improving positioning stability while adding only minimal system complexity.
Data Source
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AI summary
Provided is a medical robot arm apparatus including a plurality of joint units configured to connect a plurality of links and implement at least 6 or more degrees of freedom in driving of a multi-link structure configured with the plurality of links, and a drive control unit configured to control driving of the joint units based on states of the joint units. A front edge unit attached to a front edge of the multi-link structure is at least one medical apparatus.