Robot Control Device Threshold Adjustment for Collision Detection
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Solution Overview
Problem
Conventional robot control devices face challenges in accurately estimating disturbance torque during state transitions, leading to misjudgment of collisions when a robot grips or releases a workpiece, as the load transmission changes, making it difficult to set appropriate threshold values for collision detection.
Innovation Solution
A robot control device with a disturbance estimating part, transition recognizing part, region defining part, position judging part, and collision judging part that adjusts threshold values based on the robot's state and location within a defined region in the state space, using rotational speed and torque of servo motors, and acquired workpiece parameters to accurately assess collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single threshold value is used for collision judgment, then the device complexity is reduced, but measurement precision deteriorates during state transitions
Solution Approach 1:
The patent applies dynamics by making the threshold value adjustable based on the robot's operational state. The collision judging part dynamically switches between a first threshold value and a second threshold value according to whether the robot is in a state where workpiece load is transmitted or not. This dynamic adaptation resolves the contradiction by allowing high measurement precision during state transitions while maintaining manageable device complexity through automated state-based switching.
Solution Approach 2:
The patent changes the parameter of threshold value based on the robot's operational state. By identifying state transitions (when load transmission changes) and switching between different threshold values, the system achieves accurate collision detection during critical transitions without requiring complex manual intervention, thus resolving the contradiction between simplicity and precision.
2Measurement precision
If threshold values are adjusted during state transitions, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent implements feedback by continuously monitoring the robot's operational state (whether workpiece load is transmitted) and using this information to automatically adjust the threshold value. The collision judging part receives feedback about the current state and switches between threshold values accordingly. This feedback mechanism improves measurement precision during state transitions while keeping device complexity manageable through automated control.
3Ease of operation
If conventional collision judgment methods are used, then ease of operation is maintained, but reliability deteriorates during state transitions
Solution Approach 1:
The patent applies preliminary action by identifying state transitions in advance and preparing the appropriate threshold value for use during these transitions. The system proactively switches to the first threshold value when a state transition is detected, before misjudgment can occur. This preliminary preparation maintains ease of operation while significantly improving reliability during critical transition periods.
Data Source
AI summary
A robot control device is configured to recognize a state transition between a state where a load of a workpiece is not transmitted to a robot and a state where the entire load of the workpiece is transmitted through a hand to the robot, and define a region which encompasses the robot and hand at the start time of the state transition, within a status space which expresses the status of the robot and hand. The collision judging part of the robot control device compares a disturbance estimated value and a first threshold value when the robot and hand are located inside the defined region, and compares the disturbance value and a second threshold value which is different from the first threshold value when the robot and hand are located outside the defined region.