Kinematic Linkage System for Bridge Crane Payload Control
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Solution Overview
Problem
Overhead bridge cranes face inefficiencies due to significant inertia added by balancing systems, particularly counterweights, which hinder horizontal motion and increase energy consumption, and existing motorized systems require powerful actuators for vertical motion, leading to friction and oscillation issues.
Innovation Solution
A movement system incorporating a bridge crane, trolley, and a movement device with four-bar mechanisms and sensors that allow precise angular displacement measurement and control, enabling smooth movement along X and Y axes while minimizing inertia and oscillations through controlled kinematic link rotation and force application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If counterweights are used to balance the payload vertically, then the vertical motion is eased, but significant inertia is added to the system which hinders horizontal motion
Solution Approach 1:
The patent uses a counterweight mechanism where a counterweight assembly is suspended from the bridge crane structure to balance the payload weight. The counterweight is connected through a cable system that allows it to rise and fall with the payload, providing gravitational balance without adding significant horizontal inertia to the moving components.
Solution Approach 2:
The system separates the vertical balancing function from the horizontal motion system. The counterweight mechanism is structurally decoupled from the trolley and bridge horizontal drive systems, allowing independent optimization of vertical support and horizontal movement without coupled inertia penalties.
2Power
If powerful actuators are used for vertical motion to support payload weight, then vertical lifting capability is improved, but friction and oscillation issues increase
Solution Approach 1:
The counterweight assembly provides gravitational balancing that significantly reduces the force required from the vertical actuator. The actuator only needs to overcome imbalances, friction, and acceleration forces rather than supporting the entire payload weight, thereby reducing friction and oscillation in the vertical drive system.
Solution Approach 2:
The system incorporates sensors that detect the position and motion state of the payload and provide feedback to the control system. This enables real-time adjustment of actuator commands to minimize oscillations and maintain smooth motion, particularly during acceleration and deceleration phases.
3Ease of operation
If compressed air systems are used for balancing, then vertical support is achieved, but significant power is required to maintain pressure
Solution Approach 1:
The patent employs a gravitational counterweight system that uses the natural force of gravity to balance the payload, eliminating the need for continuous power input. The counterweight passesively balances the load throughout its range of motion, requiring energy only for initial positioning and overcoming minor friction losses.
Solution Approach 2:
The counterweight mechanism is self-regulating and automatically adjusts to payload position changes without external power input. As the payload moves vertically, the counterweight automatically follows, maintaining balance through gravitational forces alone, thereby achieving energy-free operation during normal movement cycles.
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
The system reduces the force required for payload movement, minimizes inertia, and suppresses high-frequency oscillations, resulting in more efficient and controlled payload transport with reduced operator effort and energy consumption.
Implementation Method 1
The movement device includes a first four-bar mechanism, a second four-bar mechanism, and a sensor. The second four-bar mechanism is operatively connected to, and suspended from, the first four-bar mechanism. Each four-bar mechanism has a pair of kinematic links and a pair of base links.
Implementation Method 2
The sensor is operatively attached to one of the joints of one of the first and second four-bar mechanisms. The sensor is configured to measure an angle of rotation of the respective kinematic link about the respective axis.
Implementation Method 3
The pair of kinematic links and the corresponding pair of base links form a parallelogram. The first, second, third, and fourth axis extend in parallel relationship to one another.
Data Source
AI summary
A movement device is moved along an X axis and a Y axis by providing a sensor configured to measure angle of rotation of at least one of a first and a second kinematic link about a respective axis of rotation. A force is imparted on the first and second kinematic links such that an angular displacement of the first and second kinematic links about the respective axis of rotation is achieved. The angular displacement of the first and second kinematic links about the respective axis of rotation is determined. The movement device is moved along the X axis and/or the Y axis in response to the determination of the angle of rotation of the first and second kinematic links about the respective axis of rotation until first and second kinematic links are vertical.