Master-Slave Robot Control for Contact Feedback and Overload Protection
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Solution Overview
Problem
Conventional master-slave manipulators face issues where the slave arm can apply excessive load to the master arm when interacting with hard objects, potentially damaging the force sensor or master arm, and fail to notify operators of contact with workpieces, making it difficult to distinguish between contact with the workpiece and the position regulating member.
Innovation Solution
A robot system with a slave unit, master unit, and system controller that generates operating commands to notify operators of operational limits, detects reaction and operating forces, and adjusts the operating mode to prevent overload and inform the operator of contact through perceivable sense information, thereby guiding the operator to adjust their force and prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the slave arm contacts a hard work object and the operator forcibly moves the master arm, then the slave arm can be moved against resistance, but excessive load is applied to the master arm and force sensor may be damaged
Solution Approach 1:
The system applies preliminary protective action by detecting when the slave arm contacts a work object and generating a master arm operating command that prevents excessive force application. The control system anticipates potential overload by monitoring contact status and preemptively adjusting the master arm's operational characteristics to stay within safe force limits, thereby preventing damage to the force sensor and master arm.
2Productivity
If the slave arm contacts a workpiece, then the slave arm can perform work, but the operator cannot perceive the contact and cannot distinguish between contact with workpiece and position regulating member
Solution Approach 1:
The system implements feedback by detecting when the slave arm contacts a work object and transmitting this information back to the operator through the master arm interface. The control system monitors the contact status and provides perceptible feedback to the operator, enabling them to distinguish between contact with the workpiece and contact with position regulating members, thereby maintaining awareness during operation.
3Ease of operation
If the master arm is designed to be lightweight for ease of operation, then the operator can manipulate it easily, but it cannot withstand excessive force without damage
Solution Approach 1:
The system applies beforehand cushioning by implementing control mechanisms that prevent excessive force from being applied to the lightweight master arm. The control system monitors operating conditions and limits the force transmission to protect the master arm and force sensor from damage, while still allowing the master arm to remain lightweight for ease of operation during normal use.
Data Source
AI summary
A robot system includes a slave unit including a slave arm having a working end, a slave arm actuator configured to drive the slave arm, and a slave-side controller configured to control the slave arm actuator based on a slave operating command for defining a target position of the working end, a master unit including a master arm having a manipulation end into which the content of manipulation is inputted by an operator, and a system controller configured to generate the slave operating command based on the content of manipulation inputted into the manipulation end. When a command corresponding to the content of manipulation is a command corresponding to a limit equivalent range corresponding to a limit of operation of at least one of the slave arm and the master arm, the system controller performs processing to give perception to the operator.