Robot Tip Position Estimation Using IMU and Encoder Fusion
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Solution Overview
Problem
Current surgical robots suffer from inaccuracies in tip position estimation due to errors from backlash, compliance, component wear, friction, mechanical tolerances, and actuator encoding, which are not accounted for in the robot's control models, especially in automated procedures and image-guided surgeries.
Innovation Solution
Incorporating Inertial Measurement Units (IMUs) at various locations along the robotic instrument, such as the tip, to fuse encoder values with IMU data using recursive estimation algorithms, enabling real-time, statistically optimized tip position estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional encoder-based control models are used, then the robot system is simple and easy to operate, but tip position accuracy deteriorates due to backlash, compliance, and mechanical errors
Solution Approach 1:
The patent combines encoder-based position data with IMU-based inertial measurement data into a unified tip position estimation system. The controller fuses these two independent measurement sources to compensate for mechanical errors, achieving higher accuracy without completely redesigning the control architecture.
Solution Approach 2:
The IMU acts as an intermediary measurement device that provides independent verification of tip position. Rather than directly controlling position through the flawed mechanical chain, the IMU provides an alternative measurement path that compensates for mechanical inaccuracies in the encoder readings.
2Measurement precision
If IMU data fusion is implemented, then tip position accuracy improves, but computational complexity and processing requirements increase
Solution Approach 1:
The system continuously fuses encoder and IMU data in real-time, creating a feedback loop that constantly updates the tip position estimate. This ongoing fusion process allows the system to maintain accuracy while managing computational load through iterative refinement rather than complex batch processing.
3Productivity
If automated procedures are used, then productivity increases, but accuracy deteriorates because robot errors cannot be compensated without human input
Solution Approach 1:
The robotic system performs self-correction by using the IMU to independently verify and compensate for its own positioning errors. This self-service capability allows automated procedures to maintain accuracy without requiring continuous human intervention or compensation, enabling both automation and precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves the accuracy of tip position estimation, enhances image-guided surgical procedures, and facilitates fast and accurate robot calibration and fault detection without external equipment.
Implementation Method 1
An inertial measurement unit (IMU) is configured to sense physical movements and to provide IMU data to the robot controller indicative of the sensed physical movements
Data Source
AI summary
An Inertial Measurement Unit (IMU) is placed on a robot and outputs inertial information such as angular velocity and linear acceleration of the tip to which it is attached. A robot controller implements a recursive estimation algorithm to fuse robot encoder values with IMU data to determine a statistically optimized estimated position of the robot tip.