Manipulator Joint Trajectory Optimization for Endoscopic Surgery
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Solution Overview
Problem
Existing miniature manipulators used in endoscopic surgery face challenges in achieving both high accuracy and efficiency due to the compounding of errors in inverse kinematic calculations, especially when dealing with a large number of joints, which affects the operability and invasiveness of the treatment.
Innovation Solution
A manipulator apparatus with a compact design featuring multiple joints, including straight-line, roll, yaw, and pitch driving joints, utilizes angle wires for simple and reliable operation, and incorporates load and position sensors to optimize joint angle trajectories for efficient movement, minimizing the number of driven joints while ensuring high accuracy and force generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of joints to be driven is large, then the capabilities and degrees of freedom of the treatment instrument are improved, but overall driving error increases due to compounding errors at each joint
Solution Approach 1:
The patent applies partial action by selectively driving only the minimum necessary number of joints required to achieve the target position and attitude of the manipulator distal end. The control apparatus calculates which specific joints need to be actuated based on the task requirements, rather than driving all available joints. This reduces the compounding of errors while still achieving the necessary degrees of freedom for the treatment instrument.
2Volume of moving object
If a miniature manipulator is designed to be compact, then it can be inserted through the forceps channel of the endoscope, but it becomes difficult to achieve both high accuracy and high efficiency
Solution Approach 1:
The patent applies dynamics by making the manipulator structure adaptable and reconfigurable. The manipulator can change its configuration and degrees of freedom depending on the specific treatment task. The control apparatus dynamically determines which joints to drive based on real-time requirements, allowing the compact manipulator to achieve high accuracy and efficiency by optimizing its operational configuration for each specific task rather than maintaining a fixed complex structure.
3Measurement precision
If inverse kinematic calculations are used to calculate joint angle trajectories, then target values for attitude and position can be found, but the number of calculated trajectories increases and processing time increases
Solution Approach 1:
The patent extracts and calculates only the essential joint angle trajectories needed to achieve the target position and attitude, rather than calculating all possible trajectories. The control apparatus identifies and computes merely the minimum necessary joint movements, removing unnecessary calculation steps. This reduces processing time while maintaining accurate target positioning by focusing computational resources on the critical degree of freedom changes required for the specific treatment task.
Data Source
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AI summary
A medical device system includes a manipulator (200) including a plurality of joints (211-219), a parameter storing portion (46) for storing joint parameters, including a largest available force, of each joint of the plurality of joints (211-219), a trajectory inputting portion (43) for inputting, as a trajectory plan, trajectories for moving a distal end of the manipulator (200) from a current position and attitude to a target position and attitude, a trajectory setting portion (45) for setting a joint angle trajectory for each joint providing a largest available force from among joint angle trajectories which allow movement to the target position and attitude with a minimum number of driven joints based on a largest available force parameter for the each joint stored in the parameter storing portion and the trajectory plan.