Distributed Lift Vehicle Control for Cooperative Payload Handling
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Solution Overview
Problem
Existing autonomous lift vehicle systems are vulnerable to communication losses and the loss of individual vehicles during cooperative lifting, leading to limited range and application, as well as instability in load adjustments.
Innovation Solution
A control system for lift vehicles that calculates control commands independently using positional states, including a separation cost function to avoid collisions, allowing each vehicle to control the payload as if it were the sole controller, without relying on external communication, and maintaining stability even with partial vehicle failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If centralized control is used to coordinate movements of lift vehicles, then cooperative lifting can be achieved, but the system becomes highly sensitive to communication losses and vehicle losses
Solution Approach 1:
The centralized control system is segmented into distributed autonomous control units, where each lift vehicle independently calculates its own control commands based on local sensor data and a cost function, eliminating reliance on continuous inter-vehicle communication
Solution Approach 2:
Each lift vehicle autonomously determines its positional state, calculates separation costs, and generates control commands independently without requiring service from other vehicles or external control systems, making the system self-sufficient and robust against communication failures
2Reliability
If centralized control is used to coordinate movements of lift vehicles, then cooperative lifting can be achieved, but the system becomes highly sensitive to the loss of individual vehicles
Solution Approach 1:
The control system dynamically adapts to changing conditions by continuously recalculating positional states and cost functions for each vehicle based on real-time sensor data, allowing automatic adjustment when vehicles are added or lost without requiring external reconfiguration
Solution Approach 2:
Each vehicle uses local sensor feedback to continuously determine its positional state relative to the payload and other vehicles, automatically adjusting its control commands in response to changes in the cooperative lifting configuration
3Quantity of substance
If lift vehicles operate in close proximity for cooperative lifting, then payload capacity is increased, but the risk of collision between vehicles increases
Solution Approach 1:
The control system proactively prevents collisions by incorporating a separation cost function that penalizes trajectories leading to close proximity between vehicles, calculating and adjusting control commands before collisions can occur
Solution Approach 2:
A cost function acts as an intermediary between the payload lifting objective and collision avoidance, mediating the trade-off by quantifying separation requirements and integrating them into the overall control command calculation
Data Source
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AI summary
Methods and apparatus to cooperatively lift a payload (110) are disclosed. An example method to control a lift vehicle (102) includes determining (704) a first positional state of the lift vehicle (102) with respect to a payload (110) controlled by a plurality of lift vehicles (102, 104, ...) including the lift vehicle (102), determining (706) a second positional state of the lift vehicle (102) with respect to a goal location, detecting distances (708) to the other ones of the plurality of lift vehicles (102, 104, ...), determining (710) a third positional state of the lift vehicle (102) based on the distances to the other ones of the plurality of lift vehicles (102, 104, ...), and calculating (712-720) a control command to control the lift vehicle (102) based on the first positional state, the second positional state, and the third positional state.