Robot Hand Control Using Motor Current Error Compensation
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Solution Overview
Problem
Industrial and intelligent service robots face challenges in stable grasping due to position errors caused by optical information errors or abrupt object movements, leading to increased grasping time and inefficiency.
Innovation Solution
A robot control method that uses a combination of motor drive current sensors, force sensors, and tactile sensors at the robot hand, along with optical sensors, to estimate and compensate for position and shape errors, allowing for precise control of the thumb and fingers to grasp objects accurately on the first attempt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If F/T sensor and touch sensor are mounted at robot hand to sense position error, then grasping stability is improved, but grasping time increases due to repeated operations
Solution Approach 1:
The patent applies preliminary action by performing error estimation using motor drive current information before the grasping operation. The controller estimates position and shape errors of the object based on motor current data obtained during the approach phase, and pre-calculates compensation values. This allows the robot to grasp the object correctly on the first attempt without requiring repeated operations with F/T sensors and touch sensors, thereby reducing grasping time while maintaining stability.
2Measurement precision
If optical sensor is used to measure object position, then grasping precision is improved, but position error occurs due to optical information error or abrupt object movement
Solution Approach 1:
The patent implements feedback by using motor drive current information as a feedback signal to estimate position and shape errors of the object. The controller continuously monitors motor current during the approach and grasping phases, compares it with expected values, and uses the deviation to estimate errors in object position and shape. This feedback mechanism compensates for optical sensor limitations and abrupt object movements, improving position accuracy while maintaining measurement precision.
Data Source
AI summary
A robot control method and apparatus estimates an error based on information of an object obtained using a motor drive current sensor, a force sensor or a tactile sensor mounted at a robot hand and information of the object obtained using an optical sensor and compensates for the error. The robot control method and apparatus includes measuring information of an object using an optical sensor or calculating information of the object input by a user, moving a robot hand to the object based on the information of the object, controlling the thumb and fingers of the robot hand to contact the object based on the information of the object, determining whether the thumb and fingers have contacted the object through a motor drive current sensor, a force sensor or a tactile sensor, and grasping the object depending upon whether the thumb and the fingers have contacted the object.