Forklift Speed Limiting Based on Expected Reverse Trajectory

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Solution Overview

Problem

Operators of industrial vehicles face reduced operability due to frequent adjustments in accelerator operation when navigating through environments with multiple objects, such as people and obstacles, as they need to constantly adjust speed to avoid collisions.

Innovation Solution

An industrial vehicle equipped with an object detector, expected trajectory derivation unit, and vehicle speed upper limit setting unit that automatically adjusts speed limits based on detected objects within the expected trajectory, allowing the vehicle to maintain a safe speed without operator intervention, with different speed limits for people and obstacles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the operator manually adjusts the accelerator operation amount to lower vehicle speed when approaching objects, then collision avoidance is achieved, but operability is reduced due to frequent adjustments

Engineering Contradiction:
Improvecollision avoidanceVSAvoidoperability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The vehicle speed control system automatically detects objects and adjusts vehicle speed without operator intervention. The control unit monitors object detection results and autonomously controls the vehicle speed to maintain safety distances, eliminating the need for manual accelerator adjustments by the operator.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system continuously receives feedback from object detection units and automatically adjusts vehicle speed based on detected object positions. The control unit processes real-time detection data and modulates vehicle speed accordingly, creating a closed-loop control system that maintains safe operation without manual input.

Inventive Principle:
Principle #23Feedback

2Reliability

If the vehicle speed is automatically limited when objects are detected within the expected trajectory, then safety is improved, but the device complexity increases due to additional control units

Engineering Contradiction:
ImprovesafetyVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control unit performs multiple functions including receiving object detection results, deriving expected trajectories, determining object positions relative to trajectories, and controlling vehicle speed. By consolidating these functions in a single multi-functional control unit, the system achieves enhanced safety without proportionally increasing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the object detection processing, trajectory calculation, position determination, and speed control functions into an integrated control system. This merging of previously separate functions into a unified control unit reduces the number of discrete components and simplifies the overall system architecture.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4071102B1Industrial vehicle
Publication Date: 2024.08.28 TOYOTA INDUSTRIES CORP
  • EP4071102B1 patent drawingFigure 1~2
  • EP4071102B1 patent drawingFigure 3~4
  • EP4071102B1 patent drawingFigure 5~8

AI summary

A forklift (10) comprises a main control device (31), a travel motor (41), a travel control device (43), and an object detection unit (51). The travel control device (43) controls the travel motor (41). The object detection unit (51) detects the position of an object being present in the backward direction of the forklift (10). The main control device (31) derives the expected trajectory (T) of the forklift (10). The main control device (31) imposes a speed limit on the forklift (10) by setting a vehicle speed upper limit (VS, AS1, AS2, DS1, DS2) when the object detected by the object detection unit (51) is located within the expected trajectory (T) and the forklift (10) is traveling in the direction of approaching the object. The main control device (31) gives commands to the travel control device (43) to prevent the vehicle speed of the forklift (10) from exceeding the vehicle speed upper limit (VS, AS1, AS2, DS1, DS2).