Rack Storage Control Unit Adaptive Acceleration
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Solution Overview
Problem
Rack storage systems consume excessive electrical energy due to maximum acceleration of all movement axes, leading to peak power consumption and inefficient energy use, despite being optimized to process orders quickly.
Innovation Solution
The control unit calculates multiple sets of coordinated movement sequences, optimizing for both high-speed and energy-efficient modes, allowing selection based on available time for a movement, enabling motors to consume less energy and reduce wear by delaying non-time-critical axes' acceleration and utilizing regenerative braking energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If maximum acceleration is applied to all movement axes, then the movement from starting point to target point is completed as quickly as possible, but electrical energy consumption increases to maximum levels with peak power demand
Solution Approach 1:
The patent applies dynamics by making the acceleration profile adaptive rather than static. The control unit dynamically adjusts the acceleration of non-time-critical movement axes based on real-time conditions, switching between maximum acceleration (when time is critical) and reduced acceleration (when energy efficiency is prioritized), thereby resolving the contradiction between speed and energy consumption
Solution Approach 2:
The patent changes the acceleration parameter of non-time-critical movement axes from a fixed maximum value to a variable value that can be adjusted between 0 and maximum acceleration. This parameter change allows the system to optimize between movement speed and energy consumption by selecting appropriate acceleration levels based on operational priorities
2Productivity
If maximum acceleration is applied to all movement axes, then the rack storage system processes orders quickly, but peak power consumption occurs due to simultaneous maximum acceleration of all motors
Solution Approach 1:
The system dynamically adjusts the acceleration profile of non-time-critical movement axes, allowing the control unit to coordinate acceleration timing across multiple motors. This dynamic coordination smooths out peak power demands while maintaining overall productivity by ensuring that time-critical axes still operate at maximum performance
3Speed
If all movement axes are accelerated at maximum speed, then the storage and retrieval device reaches the target point quickly, but wear on motors increases
Solution Approach 1:
The patent applies local quality by differentiating the acceleration treatment between time-critical and non-time-critical movement axes. Time-critical axes receive maximum acceleration to maintain speed, while non-time-critical axes receive reduced acceleration to minimize wear, thereby locally optimizing the balance between speed and reliability for each axis based on its specific role
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
This approach reduces electrical energy consumption without compromising the efficiency of the rack storage system, offering significant energy savings and lower wear on motors, while maintaining operational efficiency.
Implementation Method 1
the electrical energy which is fed back during braking of a movement axis by a generator-operating mode of the corresponding motor to be made available for consumption to the other motors
Data Source
AI summary
A rack storage system 1 and a method for controlling the movement path of a storage and retrieval device in a rack storage system, including at least one storage and retrieval device with at least two movement axes x, y which can be controlled independently of one another and are operated by electric motors, to carry out a movement from a starting point to a target point 4 to transfer stored goods within the rack storage system and/or into or out of the rack storage system, having a control unit for controlling the motors of the movement axes x, y and an electric intermediate circuit for exchanging fed-back electrical energy between the motors. The control unit pre-calculates the movement sequences, necessary for a movement from the starting point to the target point, of the individual movement axes x, y and coordinates them with one another, and actuates the motors of the movement axes x, y so the storage and retrieval device carries out the movement on a pre-calculated movement path which is based on a set of movement sequences, coordinated with one another, of the individual movement axes x, y. The control unit calculates a quantity with a plurality of sets of movement sequences which are coordinated with one another, which contains at least a first set with movement sequences which are optimized with respect to the speed of the movement, for a high-speed operating mode, and a second set with movement sequences which are optimized with respect to the consumption of electrical energy, for an economical operating mode. The control unit selects a set with movement sequences from the calculated quantity on the basis of operation parameters of the rack storage system in order to actuate the motors of the movement axes in order to carry out a movement path.