Manipulator Calibration via Load Measurement and Friction Compensation
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Solution Overview
Problem
Conventional manipulator systems face challenges in accurately calibrating the joint portions of medical devices, particularly due to variations in load conditions and frictional forces during bending operations, which affect the precision and reliability of the driving force transmission.
Innovation Solution
A method involving a calibration process that includes arranging the manipulator in a usable state, measuring loads using a predetermined drive pattern, and setting control parameters based on measured loads to compensate for friction and ensure accurate joint operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration is performed without considering load conditions and frictional forces, then the calibration process is simple, but the precision and reliability of joint operations deteriorate
Solution Approach 1:
The patent applies preliminary action by performing calibration operations before actual use, during which the manipulator is driven through predetermined motion patterns to measure loads and frictional forces in advance. This allows the system to establish accurate control parameters prior to operational use, ensuring precision without adding complexity to the operational phase.
Solution Approach 2:
The patent implements feedback by measuring the actual load and frictional forces generated during calibration operations, then using these measured values to adjust and determine control parameters. This closed-loop approach ensures that the control parameters accurately reflect the real mechanical conditions, improving calibration precision while maintaining a systematic process.
2Reliability
If the manipulator is calibrated in a fixed state, then the calibration process is straightforward, but the reliability across various bending states deteriorates
Solution Approach 1:
The patent applies dynamics by performing calibration operations in multiple different bending states rather than a fixed state. The manipulator is sequentially positioned in various bending configurations, and load measurements are taken in each state. This dynamic approach ensures that the control parameters account for frictional force variations across all operational states, improving reliability while the systematic procedure maintains ease of operation.
Solution Approach 2:
The patent implements parameter changes by varying the bending state parameters during calibration. By changing the manipulator's configuration parameters (bending angles, joint positions) through predetermined patterns, the system captures frictional force characteristics across different operational conditions. This ensures the control parameters are valid throughout the full range of motion, enhancing operational reliability.
3Manufacturing precision
If frictional forces are not compensated during calibration, then the calibration process is simpler, but the precision of driving force transmission deteriorates
Solution Approach 1:
The patent implements feedback by measuring the actual frictional forces and loads generated during calibration operations, then using these measured values to determine control parameters that compensate for friction. The control parameters are specifically set based on the measured frictional force characteristics, ensuring accurate driving force transmission while systematically handling the compensation process.
Solution Approach 2:
The patent converts the harmful effect of frictional forces into a beneficial measurement parameter. By deliberately measuring the frictional forces during calibration operations and incorporating these measurements into the control parameter setting, the system transforms friction from an error source into useful information that improves driving force transmission precision.
Data Source
AI summary
A method of calibrating a manipulator including a joint portion, a drive unit that generates a driving force for driving the joint portion, and a driving force transmission member that is inserted into a tubular member and transmits the driving force generated from the drive unit to the joint portion includes: an arrangement step of arranging the manipulator in a usable state; a load-measuring step of issuing an operation command based on a predetermined calibrating drive pattern to the drive unit and measuring a load generated in the manipulator at that time; and a control parameter-setting step of setting a main-driving control parameter based on the load measured in the load-measuring step.