Forklift Pedestrian Mode Double-Actuation Control
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Solution Overview
Problem
Industrial trucks with traction drives are not safely or simply operable when the operator is not on the driver's platform, particularly during pedestrian operations, as existing systems lack intuitive control mechanisms and safety features to prevent operating errors.
Innovation Solution
Implementing a method where the traction drive is actuated only by double activations of the accelerator within a predetermined time period when the operator is not on the platform, with a return to neutral position after the first actuation, and using a sensor device to detect the operator's presence or absence to switch between passenger and pedestrian modes, reducing maximum speed and steering angle in pedestrian mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the accelerator is made operable in pedestrian mode without additional control elements, then ease of operation is improved, but safety deteriorates due to risk of operating errors
Solution Approach 1:
The system requires a preliminary double actuation of the accelerator pedal before the traction drive becomes active in pedestrian mode. This preliminary action (first actuation) prepares the system by releasing the brake, while the second actuation within a predetermined time window actually activates the drive, preventing accidental activation while maintaining ease of operation
Solution Approach 2:
The control device monitors the actuation of the accelerator pedal and provides feedback by detecting whether a second actuation occurs within a predetermined time period after the first actuation. This feedback mechanism determines whether to activate the traction drive, creating a safe yet simple control system without additional control elements
2Reliability
If the maximum speed is reduced in pedestrian mode, then safety is improved, but productivity deteriorates
Solution Approach 1:
The system dynamically adjusts the maximum speed of the traction drive based on the operating mode detected by the sensor device. In pedestrian mode, the maximum speed is limited to a lower value to ensure safety, while in passenger mode the full speed range is available, optimizing both safety and productivity for each operational context
3Reliability
If the accelerator requires double actuation within a predetermined time period, then safety is improved, but device complexity increases
Solution Approach 1:
The existing accelerator pedal is given multiple functions: it serves as both the primary control for activating the traction drive and as a release mechanism for the brake system. The control device evaluates the actuation pattern to determine whether to activate the drive or release the brake, eliminating the need for separate control elements and keeping the device complexity low while maintaining safety
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a method for operating a forklift truck (1) with a drive system, a driver's workstation (7) formed by a driver's platform (8) for a standing operator (P), and a steering device (11) on which at least one drive transmitter (B1; B2) is arranged, the drive system being actuated when actuated by the operator (P), wherein the drive transmitter (B1; B2) has a first movement option (M1) for forward travel of the forklift truck (1), a second movement option (M2) for reverse travel of the forklift truck (1), and a neutral position. In an operating state in which the operator (P) is not on the driver's platform (8), the drive system is actuated by means of the drive transmitter (B1; B2) only if at least two actuations of the drive transmitter (B1; B2) in one of the movement options (M1; M2) are carried out within a predetermined period.