Industrial Robot Restart Control After Power Interruption
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Solution Overview
Problem
Industrial robots face challenges in quickly and reliably restarting after sudden power failures due to loss of synchrony between control technology state models and actual states, requiring manual calibration or homing runs, which are time-consuming and prone to errors.
Innovation Solution
A method involving continuous storage and processing of position data, speed, and braking states in non-volatile memory, allowing the industrial robot to resume operation based on pre-interruption states if all axes were stationary and braked, thereby avoiding recalibration in safe conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual calibration or homing runs are performed after power failure, then reliability of position data is improved, but loss of time increases due to time-consuming recalibration
Solution Approach 1:
The patent continuously records position data, speed, and braking state in non-volatile memory before power failure occurs. This preliminary recording of operational state allows the robot to resume without recalibration after power restoration, eliminating the time-consuming homing runs while maintaining position accuracy through the stored pre-interruption state information.
Solution Approach 2:
The patent creates a digital copy of the robot's operational state (position data, speed, braking state) and stores it in non-volatile memory. This copied state information serves as a backup that can be restored after power failure, replacing the need for physical recalibration or homing runs and significantly reducing restart time while preserving position reliability.
2Measurement precision
If safe absolute position encoders with multi-turn capability are used, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex safe absolute position encoders with a simpler approach using incremental encoders combined with continuous digital recording of position data, speed, and braking state in non-volatile memory. This substitution eliminates the need for complex multi-turn absolute encoders while achieving equivalent position recovery capability through software-based state management and braking state monitoring.
Solution Approach 2:
The patent introduces an intermediary layer of control logic that monitors braking states and manages the recording/restoration of operational parameters. This intermediary control system bridges the gap between simple incremental encoders and the need for reliable position recovery, eliminating the requirement for expensive safe absolute encoders while maintaining measurement precision through coordinated control of braking and data recording.
3Reliability
If battery-buffered designs or UPS systems are implemented, then reliability during power interruption is improved, but device complexity, cost, and maintenance requirements increase
Solution Approach 1:
The patent extracts the essential function of power backup by selectively powering only the non-volatile memory and control logic during power interruptions, rather than maintaining full system power through batteries or UPS. This extraction approach achieves the necessary reliability for position data preservation without the complexity and cost of complete system power backup solutions.
Solution Approach 2:
The patent uses inexpensive non-volatile memory components that can retain data through power interruptions without requiring expensive battery-buffered designs or UPS systems. The control logic leverages the characteristics of non-volatile memory to maintain position and operational state information during brief power failures, achieving reliability through cost-effective, maintenance-free storage solutions rather than complex power backup infrastructure.
Data Source
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AI summary
The invention relates to a method and a control device (3, 3', 3'') for the safe operation and/or safe and rapid resumption of operations of an industrial robot (2) after a power failure or power interruption. According to the invention, while the industrial robot (2) is operating speed or standstill states of all relevant movement drives (9) or movement axes (10) are stored continuously as speed characteristics in at least one non-volatile storage unit (21). In addition, the respective drive states or braking states of the brake devices (13) of all movement drives (9) or movement axes (10) are continuously stored as brake characteristics in the at least one non-volatile storage unit (21). When operations are resumed after a sudden power interruption, the most recently stored states are evaluated and, on the basis of the evaluation, a decision is taken whether it is possible to resume operations without referencing or recalibration of the industrial robot (2), or whether referencing or recalibration should be recommended or is necessary.