Robot Safety Control Modes for Power Interruption
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Solution Overview
Problem
Motor-based robots face unexpected stoppages due to unintentional power source interruptions, which can hinder their operational purposes and result in unsafe outcomes, especially in movable devices like walking robots.
Innovation Solution
A method is implemented to control robots with a main power source and a subsidiary power source, allowing the robot to switch to safety control modes such as coast, brake, hold position, or keep previous command modes based on the current state, ensuring stable operation even when the main power source is cut off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a motor-based robot uses a single main power source, then the device complexity is reduced, but the reliability deteriorates when power is unintentionally cut off
Solution Approach 1:
The power source system is segmented into a main power source and a subsidiary power source. The main power source serves as the primary power supply during normal operation, while the subsidiary power source serves as a backup. This segmentation allows the robot to maintain operational reliability during power interruptions without significantly increasing overall system complexity.
Solution Approach 2:
The subsidiary power source is prepared in advance as a backup power supply. Before a power interruption occurs, the system is configured to switch to the subsidiary power source if the main power source is cut off. This preliminary preparation ensures that the robot can continue operation or execute safety control modes without interruption, maintaining reliability.
2Reliability
If the robot switches to safety control modes upon power cutoff, then the reliability is improved, but the device complexity increases due to multiple control modes
Solution Approach 1:
The robot implements four different safety control modes (coast mode, brake mode, hold position mode, and keep previous command mode) that can be dynamically selected based on the current operational state. The controller determines the appropriate mode by evaluating real-time conditions such as motor voltage, current, and torque, allowing the system to adapt to different scenarios and maintain safety reliability.
Solution Approach 2:
The system changes operational parameters by selecting different safety control modes based on motor state parameters. When power is cut off, the controller evaluates motor voltage, current, and torque levels, and switches between different control modes (coast, brake, hold position, or keep previous command) to achieve safe operation. This parameter-based selection ensures reliability without requiring overly complex control logic.
3Object-affected harmful factors
If the robot rapidly stops in coast mode, then the safety is improved, but the productivity deteriorates due to operation interruption
Solution Approach 1:
The robot implements four different safety control modes (coast mode, brake mode, hold position mode, and keep previous command mode) that can be dynamically selected based on the current operational state. The controller determines the appropriate mode by evaluating real-time conditions such as motor voltage, current, and torque, allowing the system to adapt to different scenarios and maintain safety reliability.
Solution Approach 2:
The system changes operational parameters by selecting different safety control modes based on motor state parameters. When power is cut off, the controller evaluates motor voltage, current, and torque levels, and switches between different control modes (coast, brake, hold position, or keep previous command) to achieve safe operation. This parameter-based selection ensures reliability without requiring overly complex control logic.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the robot to safely and effectively complete operations by rapidly stopping, slowly braking, maintaining position, or continuing previous commands, thereby preventing unexpected results and ensuring safety during power source disruptions.
Implementation Method 1
The brake mode may enable the operation of the robot to slowly stop using back electromotive force of the motor
Data Source
AI summary
A robot which is able to complete all or a part of desired operations and take a safety countermeasure in order to prevent an unexpected result from being obtained, even when a power source of a motor-based robot is unintentionally and suddenly cut off. A method of controlling a robot, which includes a main power source, a subsidiary power source and a motor to receive power from at least one of the main power source and the subsidiary power source, includes driving the motor using power supplied from the subsidiary power source if power supplied from the main power source is cut off, selecting at least one of a plurality of safety control modes to stably control the robot in consideration of a current state of the robot, and controlling the robot to operate in the selected safety control mode.