Master-Slave Robot Force Feedback Correction for Inertia Mismatch
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Solution Overview
Problem
In master-slave robot systems, when the slave and master mechanisms have different inertia forces, feeding back force from the slave to the master can result in large movements of the master due to inertia forces, potentially causing harm, especially when handling delicate or living tissues. Existing methods either fail to prevent large movements of the master or diminish the feedback force, making it difficult for operators to feel the force accurately.
Innovation Solution
A control apparatus and method for a master-slave robot that includes a force information acquiring unit, a force correction determination unit, a force correction unit, and a force transmitting unit, which corrects the force feedback based on velocity information and determines a correction method to maintain or oscillate the force within a predetermined range, ensuring the master mechanism is not excessively moved while allowing the operator to feel the corrected force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If force acting on the slave is fed back to the master without correction, then force feedback function is achieved, but large movements of master occur due to inertia force difference
Solution Approach 1:
The patent changes the parameter of force feedback by introducing a correction amount that is added to the detected force. The correction amount is calculated based on the difference between the master's and slave's inertia forces, thereby adjusting the feedback force to compensate for inertia differences and prevent excessive master movement.
2Object-affected harmful factors
If correction is applied to prevent large movements of master, then safety is improved, but operator cannot easily feel the feedback force
Solution Approach 1:
The patent applies a counterweight principle by introducing a correction amount that offsets the harmful effect of inertia force difference. The correction amount is calculated to counterbalance the excessive force feedback caused by inertia differences, thereby preventing large master movements while maintaining the operator's ability to perceive the feedback force through the corrected value.
Data Source
AI summary
A master-slave device grips an object and performs a task while being in contact with a to-be-treated object. A force detection unit measures force information given to a slave mechanism. A force correction determination unit determines a force correction part serving as information from correction start to end times of force information transmitted to a master mechanism and, as a correcting method to perform correction, a first method determining a gain such that a reduction in absolute value of force information at the force correction part is maintained for a predetermined period of time or a second method determining a gain such that a reduction and an increase in the absolute value are repeated within a range that is not more than a value by reducing the absolute value. A force correction unit corrects information of a type of a force based on the force correction part and the gain.