Motor Braking Switch Architecture With Redundant Fault Feedback
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Solution Overview
Problem
Existing braking systems for electric motors often have single points of failure that can fail without warning, posing safety concerns in mobile robots and automatic guided vehicles, as they may not reliably slow or stop the motor and its load in a timely manner.
Innovation Solution
A safety switching system with multiple independent switching units, including a multi-phase shorting system, an electromechanical brake system, and a feedback system, which monitors and reports operational readiness to ensure reliable braking by diverting power from motor windings and engaging an electromechanical brake, with progressive multi-stage braking stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single braking system is used, then the device complexity is reduced, but the reliability of braking is compromised due to single points of failure
Solution Approach 1:
The braking system is divided into multiple independent switching units (first switching unit with first solid state switch, second switching unit with second solid state switch) that can operate independently. Each unit has its own feedback unit for monitoring, creating redundant pathways that eliminate single points of failure while maintaining manageable system complexity through modular design.
Solution Approach 2:
The system implements feedback units that continuously monitor the operational status of each switching unit and solid state switch beforehand. When a fault is detected in one unit, the system proactively activates the other unit to compensate, cushioning against potential braking failure before it occurs.
2Reliability
If multiple independent switching units are implemented, then the reliability of braking is improved, but the device complexity increases
Solution Approach 1:
The system segments the braking function into multiple independent switching units, each with dedicated solid state switches and feedback units. This segmentation improves reliability through redundancy while the modular structure keeps each unit simple and manageable.
Solution Approach 2:
Each switching unit incorporates a feedback unit that continuously monitors the operational status of its solid state switches. This feedback mechanism enables the safety controller to detect faults early and activate redundant units, improving reliability while the automated feedback loop reduces the need for complex manual monitoring systems.
3Duration of action of stationary object
If solid state switches are used instead of mechanical switches, then the durability is improved, but the cost of the components increases
Solution Approach 1:
The system replaces mechanical switches with solid state switches in both switching units. This substitution eliminates mechanical wear and tear, significantly improving durability and lifespan. Although solid state switches have higher individual component costs, the increased reliability and reduced maintenance requirements provide long-term value.
4Difficulty of detecting and measuring
If feedback monitoring is implemented for all switches, then the fault detection capability is improved, but the device complexity increases
Solution Approach 1:
The feedback system is segmented into separate feedback units, with each feedback unit dedicated to monitoring a specific switching unit and its solid state switches. This segmentation improves fault detection capability by providing focused monitoring while keeping each feedback unit simple and manageable, reducing overall system complexity.
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
The system ensures timely and reliable braking of electric motors by diverting power, using multiple independent switching units and an electromechanical brake, thereby enhancing safety and minimizing the risk of damage, with features like adjustable delay periods and fault detection.
Implementation Method 1
Each of the switching units may include a plurality of normally-closed solid state switches configured to close and connect a respective motor winding of the plurality of motor windings to an electrical ground
Implementation Method 2
The electromechanical brake system may be configured to mechanically brake the motor, and may include an independent third switching unit connected to an electromechanical brake
Data Source
AI summary
A safety switching system and method for braking an electric motor in a mobile device. A multi-phase shorting system brakes the motor by diverting power from the motor windings. Multiple independent switching units each include a switch control unit controlling multiple normally-closed switches which, in response to a safety controller, close to connect a respective motor winding to electrical ground. An electromechanical brake system mechanically brakes the motor. An independent switching unit includes two normally-open switches which, in response to the safety controller, opens to activate an electromechanical brake. A feedback system communicates to the safety controller a switch failure of any of the switches either as a short circuit fault or an open circuit fault. The feedback system may include an analog and/or a digital feedback system. If a switch failure is detected, the safety controller may activate the multi-phase shorting system and the electromechanical brake system.