Joystick Overload Detection for Aerial Work Platform Safety
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Solution Overview
Problem
Aerial work platforms pose a risk of operator entrapment when the telescopic arm is extended, leading to joystick overload and loss of control, as the operator becomes trapped between the basket and a building, causing frantic and ineffective joystick movement, which existing safety mechanisms fail to address effectively.
Innovation Solution
An operating device with a manual control transmitter equipped with a Hall sensor for movement detection and strain gauges as force sensors, which output signals to an evaluation unit to detect joystick overload, triggering a counter-movement to free the operator and prevent further damage, integrated into the joystick module for enhanced safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the operator controls the aerial work platform from the basket, then the operator can directly control the platform position, but the operator risks being trapped between the basket and a building
Solution Approach 1:
The control device detects joystick overload conditions before complete entrapment occurs. The evaluation unit continuously monitors force sensor signals and initiates protective counter-movements of the telescopic arm when overload thresholds are exceeded, preventing the operator from being fully trapped between the basket and building structure
Solution Approach 2:
The system implements continuous feedback through force sensors that measure loads on the joystick. The evaluation unit processes these signals in real-time and automatically responds by controlling the telescopic arm to move away from the overloaded position, creating a closed-loop safety mechanism that prevents entrapment while maintaining operator control capability
2Ease of operation
If the operator is trapped and tries to move the joystick frantically, then the operator attempts to free themselves, but the joystick mechanism may suffer permanent damage
Solution Approach 1:
The evaluation unit detects joystick overload conditions before permanent damage can occur. By monitoring force sensor signals and comparing them against predefined thresholds, the system initiates protective counter-movements of the telescopic arm that free the operator while limiting the duration and magnitude of forces applied to the joystick mechanism, preventing permanent damage
Solution Approach 2:
The control device implements protective measures by detecting overload conditions and automatically initiating counter-movements that reduce excessive forces on the joystick. This cushioning effect protects the mechanical components from damage while still allowing the operator to attempt self-rescue movements within safe force limits
3Productivity
If the telescopic arm continues to extend during operator entrapment, then the platform reaches the desired position, but the operator becomes increasingly trapped and injured
Solution Approach 1:
The force sensors continuously monitor loads on the joystick and provide real-time feedback to the evaluation unit. When the operator becomes trapped and excessive forces are detected, the system automatically interrupts normal operation and initiates protective counter-movements of the telescopic arm, stopping the extension process and preventing further operator injury while maintaining the ability to resume positioning operations
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 solution effectively prevents operator entrapment by detecting joystick overload and initiating a counter-movement to release the operator, ensuring safe operation and reducing the risk of permanent damage to the joystick mechanism.
Implementation Method 1
The manual control transmitter (300) has a movement sensor (400), for example a Hall sensor
Implementation Method 2
At least one strain gauge sensor (41, 42) is provided on the circuit board (43)
Data Source
Figure 1
Figure 2a
Figure 2b~2c
AI summary
An operating device for a construction machine comprises a base plate, a hand-held remote control, a motion sensor, and a force sensor. The hand-held remote control is arranged at an angle to the base plate and is movable at least one-dimensionally relative to the base plate. The motion sensor is configured to determine the position and/or movement of the hand-held remote control relative to the base plate and to output a movement signal depending on the determined position and/or movement. The force sensor is configured to determine a force acting on the hand-held remote control and to output a force signal depending on the determined force.