Two-Channel Load Retention for Stored Potential Energy Safety
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing systems face challenges in providing a safe operating condition for industrial machines with stored potential energy, as a single failure in the motor brake or motor drive can lead to unintended release of stored energy, necessitating redundant systems that increase complexity and cost.
Innovation Solution
A two-channel system where a first safety channel controls the holding brake to prevent motion and a second safety channel independently monitors and controls torque production from the motor drive, ensuring that a single failure does not result in unexpected energy release, with each channel operating independently to maintain safe load retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single holding brake or motor drive is used to control load retention, then device complexity is reduced, but safety reliability deteriorates due to single-point failure risk
Solution Approach 1:
The control system is segmented into two independent safety channels (first safety channel for brake control, second safety channel for torque control) that operate autonomously. Each channel has separate processors and control logic, eliminating single-point failure while avoiding the complexity of fully redundant dual-brake systems.
Solution Approach 2:
The motor drive acts as an intermediary that receives commands from both safety channels and coordinates their actions. The drive integrates brake control signals from the first channel and torque control signals from the second channel, enabling cooperative safety control without requiring separate physical systems.
2Reliability
If redundant systems are implemented to prevent single failure, then safety reliability improves, but device complexity and cost increase
Solution Approach 1:
The motor drive performs multiple safety functions simultaneously: it controls the holding brake via the first safety channel and independently manages motor torque via the second safety channel. This multi-functionality provides redundant safety control without requiring separate dedicated systems for each function.
Solution Approach 2:
The patent merges brake control and torque control into a single integrated motor drive unit that processes both safety channels. This consolidation provides the reliability of redundant systems while reducing the overall device complexity compared to having separate independent brake and torque control systems.
3Use of energy by moving object
If the motor drive is disabled to conserve energy during idle periods, then energy efficiency improves, but safety reliability deteriorates as the system loses ability to control potential energy release
Solution Approach 1:
The holding brake is activated in advance before the motor drive is disabled. By setting the brake while the motor is still controlled, the system ensures that potential energy is secured before entering the energy-saving idle state, maintaining safety reliability while enabling energy conservation.
Solution Approach 2:
The system dynamically transitions between active control mode and energy-saving idle mode. During idle periods, the brake remains engaged to maintain safety while the motor drive operates in a low-power state, allowing the system to adapt its energy consumption based on operational requirements without compromising safety.
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
An improved system and method for providing safety-rated operation of a motor and motor drive controlling operation of a load with stored potential energy includes a two-channel method of monitoring and retaining control of the load. A first safety channel is configured to control operation of a holding brake, which provides sufficient holding force to retain the stored potential energy in the load. A second safety channel is configured to independently enable and disable torque production from the motor drive controlling operation of the motor. When torque production from the motor drive is enabled, the motor drive and motor are able to provide sufficient torque to retain the stored potential energy in the load. Monitoring and subsequent control of each safety channel is provided to ensure that a single failure in either channel will not cause the unexpected release of the stored potential energy from the load.