Passive Controller Tracking for Constrained Robotic Instruments
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Solution Overview
Problem
Existing remotely controlled robotic systems, particularly surgical robotics, are hindered by the need for expensive and bulky active controllers with servo motors, leading to high manufacturing costs and user discomfort due to unnatural movement biases, and passive controllers lack precise tracking in constrained environments.
Innovation Solution
A passive controller system using an inverse kinematics algorithm to determine optimal joint parameters for a robotic instrument, allowing it to mimic a desired pose closely within constraints, without active torque variation, and incorporating an unlock mechanism for interrupted tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active controllers with servo motors are used to actively vary torque in joints, then the controller can hold the handle in the last position and orientation, but the controller becomes expensive and bulky
Solution Approach 1:
The patent removes the active torque variation mechanism (servo motors) from the controller, extracting only the essential function of position tracking. The controller becomes a passive device that freely follows user movements without active compensation, eliminating bulky components while maintaining core functionality.
Solution Approach 2:
The patent replaces expensive active controllers with a simple passive controller structure. The focus shifts from maintaining controller stability through active components to achieving accurate tracking through software-based inverse kinematics algorithms, significantly reducing hardware costs and complexity.
2Reliability
If active torque variation is used in controller joints, then the handle can be held in position, but user discomfort and unnatural movement biases occur
Solution Approach 1:
The passive controller allows the user's own movements to directly determine the controller's position without active intervention. The system serves itself by using the user's natural movements as the input signal, eliminating the need for torque compensation that causes discomfort and unnatural biases.
3Ease of manufacture
If a passive controller is used without active torque variation, then manufacturing costs are reduced, but precise tracking in constrained environments becomes difficult
Solution Approach 1:
The patent replaces the mechanical active torque variation system with a computational solution. Inverse kinematics algorithms process the passive controller's position data and calculate the appropriate robotic instrument movements, achieving precise tracking through software rather than complex mechanical actuation.
Solution Approach 2:
The system changes from active physical parameter control (torque variation) to computational parameter processing (inverse kinematics calculations). By transforming the control problem into a mathematical optimization problem, the system achieves precise tracking in constrained environments without requiring active mechanical components.
Data Source
AI summary
An apparatus including computer program code configured to cause the apparatus to: receive a command defining a desired pose of an end effector of a robotic instrument; determine, based on the command, joint parameters for each joint of the robotic instrument using an inverse kinematics algorithm to enable the end effector to mimic the desired pose as closely as possible, wherein the algorithm is configured to reiteratively calculate a pose of the end effector and identify the calculated pose with the smallest tracking error as a global solution if the tracking error is smaller than that associated with a current pose of the end effector, otherwise identify the current pose as the global solution; and wherein the apparatus is configured to generate a motor command to reconfigure the joints according to the global solution if the calculated pose with the smallest tracking error is identified as the global solution.