Elevator Car Separation Assurance via Distributed Braking Control
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Solution Overview
Problem
In ropeless elevator systems, especially in high-rise buildings with multiple elevator cars, there is a need for reliable braking and separation assurance between cars to prevent collisions and ensure safe operation, as existing systems lack effective mechanisms for coordinated braking and separation control.
Innovation Solution
A method and system that includes a safety motion state estimator to determine the position and velocity of each car, a safety assurance module to create a separation map, and a recovery manager to initiate events such as Ustops or secondary brake actuation to ensure safe separation, with a controller and brake controller configured to actuate brakes and manage communication losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If mechanical braking is actuated from the car itself in ropeless elevator systems, then braking response time is improved, but system complexity increases due to the need for communication links between car and hoistway side for coordinated braking operations
Solution Approach 1:
The braking control system is segmented into distributed components: a brake controller carried by each elevator car that can independently actuate brakes, and a hoistway-side controller that coordinates braking operations. This segmentation allows local braking decisions at each car while maintaining overall system coordination, improving response time without proportionally increasing overall system complexity.
Solution Approach 2:
The brake controller on each car is pre-configured with braking logic and can independently initiate braking actions without waiting for hoistway-side commands. This preliminary action capability ensures immediate braking response while the communication link provides only coordination information, not mandatory control signals.
2Productivity
If multiple elevator cars operate in a single hoistway, then productivity is improved, but the risk of collision increases requiring complex separation assurance mechanisms
Solution Approach 1:
The safety assurance module continuously calculates separation maps in advance that define safe operating zones for each car. These pre-computed separation boundaries are used by the brake controller to automatically initiate braking actions before potential collisions could occur, enabling multiple cars to operate safely in the same hoistway without complex real-time intervention.
Solution Approach 2:
The system implements continuous feedback through the safety motion state estimator that monitors position and velocity of each car, feeds this information to the safety assurance module, which updates separation maps and communicates braking requirements to individual car controllers. This closed-loop feedback ensures collision prevention while maintaining high productivity.
3Ease of operation
If braking of one car is allowed to influence separation between cars, then ease of operation is improved, but control precision deteriorates making it difficult to maintain safe separation distances
Solution Approach 1:
The control system segments braking authority by assigning independent brake controllers to each car, with each controller receiving specific separation maintenance instructions from the hoistway-side controller. This segmentation allows each car to brake independently when needed while the hoistway controller coordinates to maintain precise separation, combining ease of independent operation with precise control.
Solution Approach 2:
The system dynamically changes control parameters by adjusting the separation map boundaries and braking force requirements based on real-time car positions and velocities. The safety assurance module modifies these parameters to maintain optimal separation distances, allowing flexible operation while preserving precise control through continuous parameter adjustment.
Data Source
AI summary
An elevator component separation assurance system includes a controller, and a brake controller. The controller includes an electronic processor, a computer readable storage medium, a safety motion state estimator, and a safety assurance module. The safety motion state estimator is configured to identify velocity and position of each one of a plurality of elevator components. The safety assurance module is configured to select a separation map from a plurality of pre-pre-programmed separation maps for each one of an adjacent component pair of the plurality of elevator components for initiating a Ustop that maintains elevator component separation. The brake controller is carried by each one of the plurality of elevator components, and is configured to actuate a secondary brake upon detection of a loss of communication with at least a portion of the controller.