Active Braking Circuit for Autonomous Mobile Devices
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Solution Overview
Problem
Existing autonomous mobile devices (AMDs) lack an effective and independent mechanism for rapid stopping, which is crucial for safety in case of unexpected collisions or system failures, relying on primary braking systems that may be inadequate or unavailable.
Innovation Solution
An active braking circuit using a complex programmable logic device (CPLD) that selectively commutates the motor to reverse its direction, providing a rapid stop mechanism independent of other systems, triggered by stop conditions such as expected or actual collisions, or component failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an active braking circuit is added to provide rapid stopping capability, then safety and reliability are improved, but device complexity increases
Solution Approach 1:
The patent introduces a dedicated active braking circuit as an intermediary system that operates independently from the primary motor control circuitry. This separate braking circuit receives stop signals and directly controls the motor to provide rapid deceleration, acting as a mediator between safety requirements and motor control without complicating the primary control system.
Solution Approach 2:
The braking function is segmented from the primary motor control system into a separate active braking circuit. This segmentation allows the braking function to be implemented independently with its own dedicated components (resistors, switches, control logic), improving reliability while keeping the overall system architecture modular and manageable.
2Speed
If the motor is commutated to reverse direction for rapid stopping, then stopping speed is improved, but stability deteriorates due to potential toppling or skidding
Solution Approach 1:
The active braking circuit applies partial braking force by controlling the duration and intensity of the reverse commutation. Rather than immediately applying full reverse power that would cause toppling, the system applies controlled partial action that provides sufficient deceleration while maintaining stability, adjusting the braking intensity based on the stopping requirements.
Solution Approach 2:
The system prepares for potential instability by implementing controlled commutation that cushions the transition during rapid stopping. The active braking circuit manages the reversal process to prevent sudden shifts that could cause toppling or skidding, effectively cushioning the mechanical transition.
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 active braking circuit ensures low latency and effective rapid stopping of the AMD without causing toppling or skidding, enhancing overall safety by providing an alternative and redundant braking mechanism.
Implementation Method 1
selectively commutates the motor to reverse its direction
Data Source
AI summary
An autonomous mobile device (AMD) includes an active braking circuit able to quickly stop the movement of the AMD. For example, the device may stop to avoid an obstacle, upon determining a failure of an internal component, upon receipt of a command, and so forth. Responsive to a signal to stop, an active braking circuit uses sensor data from a driving motor moving with a first rotation to actively commutate that motor to an opposite rotation, bringing the AMD quickly to a stop. In some implementations, the active braking circuit may include an independent power source and motor drivers and operate as a backup to a primary braking system.