Conveyor Velocity Synchronization for Robot Pick-and-Place Flow
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Solution Overview
Problem
In industrial robot picking and placing systems with parallel conveyors, achieving a balance between item pickup and empty place filling is challenging, especially when conveyor velocities differ due to varying densities, leading to potential overflow and reduced efficiency.
Innovation Solution
A method to control the velocity of the empty place conveyor by creating pairs of items and empty places based on position data, adjusting the conveyor speed to ensure simultaneous arrival at the border of the working area, thereby reducing overflow and increasing the chances of matching items and empty places being available for the robot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the velocity of the empty place conveyor is fixed and predetermined, then the system structure is simple, but items and empty places cannot be synchronized, causing overflow and reduced productivity
Solution Approach 1:
The empty place conveyor velocity is changed from fixed to dynamically adjustable. The control system continuously monitors the positions of items and empty places, and adjusts the conveyor velocity in real-time to synchronize the arrival of items and empty places at the robot working area, thereby improving picking efficiency without requiring complex mechanical structures
Solution Approach 2:
A feedback control mechanism is implemented where the control system receives continuous position data from sensors tracking items on the item conveyor and empty places on the empty place conveyor. Based on this feedback, the system calculates the required velocity adjustment to achieve synchronization, creating a closed-loop control system that maintains optimal operation
2Reliability
If a buffer of stationary empty places is introduced to prevent overflow, then overflow is reduced, but system efficiency decreases due to extra movement time
Solution Approach 1:
The buffer zone is eliminated entirely by directly synchronizing the empty place conveyor velocity with the item conveyor velocity. The control system calculates the exact velocity needed for empty places to arrive at the robot simultaneously with items, removing the intermediate buffer storage and its associated time delays
Solution Approach 2:
The control system performs preliminary calculation of the required conveyor velocity based on current positions and distances. By pre-computing the optimal velocity before items reach the working area, the system ensures synchronized arrival without needing buffer zones or last-minute speed adjustments
3Productivity
If the velocities of item conveyor and empty place conveyor are made similar, then items and empty places can be synchronized, but the system cannot adapt to different densities of items and empty places
Solution Approach 1:
The system dynamically changes the velocity parameter of the empty place conveyor based on real-time conditions. Instead of using a fixed velocity or simple averaging, the control system continuously adjusts the velocity parameter to match the actual density and spacing of items and empty places, enabling both synchronization and adaptability
Data Source
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AI summary
A method for controlling a velocity of a conveyance path of a system (1 1 ) including an industrial robot (2), a first conveyance path (4) configured to transfer items (5) within a working area (b2) of the robot (2) with a velocity vi, and a second conveyance path (6) configured to transfer empty places (7) within the working area (b2) of the robot (2) with a velocity V2. The method includes: obtaining position data for a plurality of items (5) and for a plurality of empty places (7); creating one or more pairs including one of the empty places (7) of the plurality of empty places (7) and a respective item (5) of the plurality of items (5); calculating, for one of the one or more pairs, a time tAs for the empty place (7) of the one pair and a time tBk for the item (5) of the one pair to reach a border (16, 17) of the working area (b2) based on position data for the one pair and the velocities vi and V2; and controlling the velocity V2 of the second conveyance path (6) based on a difference between the time tAs and a time (tBk+At), where At is a predetermined time difference.