Master-Slave Manipulator Control for Redundant Joint Motion
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Solution Overview
Problem
Master-slave manipulators face challenges in efficiently controlling redundant degrees of freedom, particularly in narrow body cavities, where existing systems struggle to intuitively operate with precision and avoid interference with surrounding tissues during procedures like suturing.
Innovation Solution
A master-slave manipulator system with a remote operation device and a slave manipulator featuring redundant joints, where a controller determines and adjusts drive ratios based on operation information from the remote device, allowing selective control of redundant degrees of freedom by calculating position and orientation change amounts to optimize joint movement and prevent unnecessary interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If redundant joints are added to the slave manipulator to enable precise positioning and orientation in narrow body cavities, then the positioning precision is improved, but the control complexity increases
Solution Approach 1:
The control system dynamically adjusts the drive ratios of redundant joints based on the operational state (whether work is being performed). This dynamic adaptation allows the system to optimize control complexity by switching between different control modes: during work operations, the distal end joint is prioritized for precision, while during non-work operations, the base joint is prioritized for stability, thereby managing control complexity adaptively
Solution Approach 2:
The invention changes the control parameters (drive ratios) of the redundant joints based on operational conditions. By modifying the drive ratio parameters dynamically - setting one ratio during work operations and another during non-work operations - the system achieves precise control without maintaining constant high complexity control mechanisms
2Object-affected harmful factors
If the slave manipulator operates with fixed drive ratios for redundant joints, then the control system is simple, but the ability to avoid interference with surrounding tissues during work operations is reduced
Solution Approach 1:
The control system transitions from fixed drive ratios to dynamic drive ratio adjustment based on operational state detection. When work operations are detected, the system dynamically switches to a drive ratio configuration that minimizes tissue interference. This dynamic approach enables the manipulator to adapt its control strategy in real-time, reducing harmful effects during critical work phases
Solution Approach 2:
The control system incorporates feedback about the operational state (whether work is being performed) to adjust drive ratios accordingly. This feedback mechanism allows the system to detect when work operations are occurring and automatically modify the control parameters to avoid tissue interference, creating a closed-loop control system that responds to operational conditions
3Productivity
If the drive ratios of redundant joints are continuously adjusted during operations, then the operational efficiency is improved, but the control computation time increases
Solution Approach 1:
The system implements dynamic drive ratio adjustment based on operational state rather than continuous adjustment. By detecting the operational state (work or non-work) and switching between predetermined drive ratio configurations, the system achieves operational efficiency improvements without requiring complex real-time computation for every control parameter adjustment
Solution Approach 2:
The control system pre-determines appropriate drive ratios for different operational states (work operations vs. non-work operations). By preparing these control parameters in advance based on the detected operational condition, the system avoids complex real-time computation during critical operations, thereby maintaining high operational efficiency while minimizing control computation time
Data Source
AI summary
A master-slave manipulator according to the present invention includes a remote operation device, serving as a master, that provides operation information corresponding to multiple degrees of freedom, a slave manipulator having a plurality of joints corresponding to multiple degrees of freedom and including a redundant joints among the joints, and a controller that controls the operation of the joints in accordance with the operation information, in which, when it is determined that a distal end of the slave manipulator operates, the controller determines, among the redundant joints, drive ratios α of a joint disposed on a base end side and a joint disposed on a distal end side within a range of 0<α<1, respectively, and drives the joints.