Automated Lifting Cart Cam Synchronization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Automated storage and retrieval systems (AS/RS) face instability and inefficiency in lifting loads due to small support areas, leading to tilting and uneven stress on central lifting cams, and existing mechanical linkages are complex, energy-inefficient, and difficult to maintain.
Innovation Solution
The use of a lifting cart with a lifting surface connected to first and second pairs of cams with asymmetric bean-shaped profiles, where the rotation of one pair opposes the other, and an electronic controller synchronizes their rotation using encoders to stabilize the load and reduce mechanical complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a central cam is used to lift the load, then the lifting mechanism is simple, but the load becomes unstable and tilts during acceleration
Solution Approach 1:
The single central cam is divided into multiple cams (at least two) distributed across the lifting surface. Each cam independently supports a portion of the load through its own cam follower, segmenting the lifting function to improve stability during acceleration and deceleration.
Solution Approach 2:
The cam profiles are designed with asymmetric bean-shaped geometry rather than symmetric circular or simple lobed shapes. This asymmetric profile optimizes the lifting and lowering motion characteristics, providing better load control and stability during dynamic operations.
2Stability of the object's composition
If the cam rotates slowly to minimize load imbalance, then load stability improves, but productivity decreases
Solution Approach 1:
Multiple cams operate in parallel to distribute the lifting load, allowing the system to achieve stable load support at higher rotation speeds than a single cam could manage. The segmented support points prevent load tilting even during faster acceleration cycles.
Solution Approach 2:
The cam profile geometry is optimized with asymmetric bean-shaped design that allows faster rotation while maintaining load balance. The specific profile parameters enable controlled acceleration and deceleration rates that improve productivity without sacrificing load stability.
3Stability of the object's composition
If mechanical linkages like chain and sprocket are used to synchronize cams, then synchronization is achieved, but device complexity and maintenance requirements increase
Solution Approach 1:
Mechanical linkages (chains, sprockets, belts) are replaced with independent motor drivers for each cam. Electronic controllers with encoders synchronize cam rotation through electronic control signals rather than mechanical coupling, eliminating the need for complex mechanical synchronization systems and reducing maintenance requirements.
Solution Approach 2:
Each cam is equipped with its own motor and encoder, making the system self-synchronizing through electronic feedback. The independent motors automatically coordinate their operation through controller communication, eliminating the need for external mechanical synchronization mechanisms.
4Stability of the object's composition
If mechanical linkages are used for cam synchronization, then cam coordination is achieved, but energy efficiency decreases due to transmission losses
Solution Approach 1:
Mechanical power transmission through chains and sprockets is replaced with direct electric motor驱动 of each cam. This eliminates mechanical transmission losses and improves energy efficiency while maintaining precise cam coordination through electronic control.
Solution Approach 2:
The intermediate mechanical transmission components (chains, sprockets, belts) are extracted and removed from the system. Each cam is directly driven by its own motor, eliminating the energy losses associated with mechanical power transmission through intermediate linkages.
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 solution enhances load stability and efficiency by minimizing lateral movement and stress, reducing maintenance needs, and optimizing energy use through synchronized cam rotation and independent motor control.
Implementation Method 1
a first and a second pair of cams that are positioned underneath the lifting surface and that have cam profiles shaped to lift the lifting surface upon rotation
Data Source
Figure 1A~1D
Figure 1E
Figure 1F
AI summary
An apparatus for lifting a load on an automated lifting cart, including a lifting surface vertically movable relative to the lifting cart, two pairs of cams positioned underneath the lifting surface having cam profiles shaped to lift the lifting surface upon rotation of the cams, a pair of encoders reading a rotation property of each pair of cams, and a controller configured to control movement of the pairs of cams by synchronizing the rotation properties of the pairs of cams by matching output from the encoders. Additionally, methods of lifting a load using an automated lifting cart including cams with a movement profile and a load profile, and methods of synchronizing drive shafts in a lifting cart using torque current measurements sent from a lead motor to a lag motor.